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Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 Subject Review p57KIP2: “Kip”ing the Cell under Control Ioannis S. Pateras, Kalliopi Apostolopoulou, Katerina Niforou, Athanassios Kotsinas, and Vassilis G. Gorgoulis Molecular Carcinogenesis Group, Laboratory of Histology-Embryology, Medical School, University of Athens, Greece Abstract p57KIP2 is an imprinted gene located at the chromosomal locus 11p15.5. It is a cyclin-dependent kinase inhibitor belonging to the CIP/KIP family, which includes additionally p21CIP1/WAF1 and p27KIP1. It is the least studied CIP/KIP member and has a unique role in embryogenesis. p57KIP2 regulates the cell cycle, although novel functions have been attributed to this protein including cytoskeletal organization. Molecular analysis of animal models and patients with Beckwith-Wiedemann Syndrome have shown its nodal implication in the pathogenesis of this syndrome. p57KIP2 is frequently down-regulated in many common human malignancies through several mechanisms, denoting its anti-oncogenic function. This review is a thorough analysis of data available on p57KIP2, in relation to p21CIP1/WAF1 and p27KIP1, on gene and protein structure, its transcriptional and translational regulation, and its role in human physiology and pathology, focusing on cancer development. (Mol Cancer Res 2009;7(12):1902–19) Introduction Throughout the evolutionary process, cells have developed sophisticated molecular machinery in order to elicit, at any moment, the proper decision with respect to cell fate. For this reason, external and internal signals are continuously monitored, assimilated, processed, and/or integrated, via complex biochemical-signaling networks (1). At the heart of this complex, decision-making molecular machinery, lies a cell nucleus-located core that resembles, in its operation, a clock apparatus (1). The determination of the cell's fate toward proliferation, arrest, differentiation, quiescence, or apoptosis relies upon this cell clock (1). The decision for cell cycle progression to occur, which is synonymous with proliferation, requires timely activation, followed by subsequent ordered inactivation of cyclin-dependent kinases (CDK; ref. 1). CDKs are activated through the formation of heterodimers with cyclins, whose concentration alters periodically Received 7/20/09; revised 9/14/09; accepted 9/16/09; published OnlineFirst 11/24/09. Grant support: European Social Fund and National Resources-(EPEAEK-II), PYTHAGORAS II (grant number 7953), the European Commission funded FP7-projects GENICA and INFLA-CARE and the SARG-NKUA grant numbers: 70/3/1703, 70/4/9913, 70/4/4281. Request for reprints Vassilis G. Gorgoulis, Antaiou 53 Str. Lamprini, Ano Patissia, GR-11146 Athens, Greece. Phone: 30-210-7462352; Fax: 30-210-6535894. E-mail: [email protected] Copyright © 2009 American Association for Cancer Research. doi:10.1158/1541-7786.MCR-09-0317 1902 during the cell cycle. Sequentially coordinated stimulation of different CDK-cyclin complexes ensures proper cell cycle progression (1). On the other hand, inhibitory effects over the activity of CDK-cyclin complexes may lead to cell cycle arrest (temporary or permanent), differentiation, senescence, quiescence, or apoptosis (1). Important negative regulators of CDKs are the CDK inhibitors (CKI). There are two families of CKIs, the INK4 and the CIP/KIP family. The INK4 family includes p16INK4a (2), p15INK4b (3), p18INK4c (4), and p19INK4d (5, 6). The INK4 members are structurally related, having four ankyrin repeats. They cause G1 arrest through competition with cyclin D, thus preventing formation of active complexes of CDK4/6-cyclin D. The CIP/KIP family includes p21CIP1/WAF1/CDKN1A (7, 8), p27KIP2/CDKN1B (9, 10), and p57 KIP2/CDKN1C (11, 12). The CIP/KIP family has a broader specificity for CDKs than the INK4 members. At low levels they bind to the CDK-cyclin heterodimer and promote their assembly, whereas at high levels they abrogate CDK activity. In this review we focus on the younger and least studied member of the CIP/KIP family, p57KIP2, presenting up-to-date evidence about the regulation of p57KIP2, its physiologic functions, and its impact in human pathology, focusing on carcinogenesis, in comparison with p21CIP1/WAF1 and p27KIP1. Structure of the CDKN1C Gene and mRNA The human CDKN1C gene resides in the telomeric end of chromosome 11, at the 11p15.5 locus (Fig. 1A; ref. 12). Mouse and rat p57KIP2 reside in the distal region of chromosomes 7 and 1, respectively (13, 14). The coding region of CDKN1C consists of four exons separated by three introns (Fig. 1A; ref. 15). p57KIP2 is rich in CpG islands both upstream and downstream of the putative transcriptional start site (16). Analysis of the CDKN1C promoter revealed the following consensus binding sites: (i) several Sp-1 (Stimulatory protein-1), (ii) ETS (erythroblastosis virus E26 oncogene), (iii) a TATA box [TBP (TATA box binding protein)], (iv) EGR1 (early growth response 1), (v) OCT1 (octamer-binding transcription factor 1), (vi) NF1 (neurofibromin 1), (vii) two CAT elements, (viii) a GRE (glucocorticoid response element), (ix) a binding site for the p63 isoform ΔNp63α, and (x) binding sites for the Hes1 (hairy and enhancer of split 1) and Herp2 (hes-related repressor protein 2) notch effectors (Fig. 1A; refs. 15, 17-21). Alternative splicing of p57KIP2 intron 1 at different 3′ splice acceptor sites produces three transcripts (Fig. 1A). The major transcript corresponds to the one with the whole intron 1 spliced out (15). The splicing and expression pattern is conserved among humans and rodents (14). Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review FIGURE 1. Structure of p57KIP2 gene and p57KIP2 protein; comparison with p27KIP1 and p21CIP1/WAF1 proteins. Ai. Ideogram of human chromosome 11. Aii. Schematic of the 11p15.5 subchromosomal region. The human p57KIP2 gene is located in the centromeric region of 11p15.5. It is transcribed from the maternal allele (large arrow), because of imprinting of the paternal allele. However, there is a leaky expression from the paternal allele (small arrow). Aiii. Structure of the human p57KIP2 gene. Transcribed regions (exons, Ex) are denoted in green boxes, with the coding regions hatched. Introns are depicted with red boxes. The human promoter encompasses several consensus binding sites for a series of transcription factors. Owing to a space limitation in the figure, see text for a full description of the transcription factors binding to the p57KIP2 gene promoter. Aiv. Splicing pattern of p57KIP2 mRNA. Three transcripts are produced because of alternative splicing of intron 1 at 3′ different acceptor sites. A3 is the major transcript produced from whole intron-1 splicing out. B. Mouse and human p57KIP2 proteins are conserved in the amino- and carboxy-terminal domains. The internal regions in mouse have been substituted in human with the PAPA domain, which is unique among the CIP/KIP members. The amino-terminal region is highly homologous between all human CIP/KIP members encompassing the CDK inhibitory domain. The CDK inhibitory domain possesses the cyclin-binding domain, the CDK-binding domain, and the 310 helix (orange boxes). The carboxy-terminal domain of human p57KIP2 has similarities with both p21CIP1/WAF1 (PCNA-binding domain) and p27KIP1 (QT box). The PCNA-binding domain is not depicted in the mouse p57KIP2 carboxy-terminal domain, because, according to Watanabe et al. (28), mouse p57KIP2 exhibits a much weaker PCNA binding activity than human p57KIP2. p57KIP2 Protein Structure of p57KIP2 Protein Human and mouse p57KIP2 encode a 316- and a 335-amino acid protein, respectively, both migrating as 57 kD by SDSPAGE electrophoresis (12). Mouse p57KIP2 protein consists of four distinct domains: (i) domain I (located in the amino- terminal region), a CDK inhibitory domain, sharing significant homology with the respective CDK inhibitory domain of p21CIP1/WAF1 and p27KIP1; (ii) domain II, a proline rich region; (iii) domain III, comprising an exceptional acidic repeat, in which every fourth amino acid is glutamic or aspartic acid; and (iv) domain IV (located in the carboxy-terminal region), Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1903 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1904 Pateras et al. containing a conserved motif, named QT box (Fig. 1B). The QT box domain is significantly homologous with the carboxyterminal domain of p27KIP1. The human and mouse p57KIP2 amino- and carboxy-terminal domains are conserved, whereas the internal domains in the mouse p57KIP2 have been substituted in human p57KIP2 with a distinct domain rich in prolinealanine repeats, named the PAPA region (Fig. 1B; ref. 12). A putative nuclear localization signal (NLS) has been recognized in the QT box domain of the mouse p57KIP2, similar to the NLS in the carboxy-terminal of mouse p21CIP1/WAF1 and mouse p27KIP1 (11). Spectroscopic and hydrodynamic analysis indicate that human p57KIP2 lacks a stable helical and β-sheet structure, although the formation of a secondary structure cannot be precluded (22). p57 KIP2 as well as p21 CIP and p27 KIP1 are considered to be highly unfolded molecules (23, 24). Proteins that are fully or partially unfolded show a binding plasticity at the expense of thermodynamic stability, are degraded faster, and have an increased rate of evolution compared with folded proteins (25-27). CIP/KIP family members have a broad specificity for CDKs and are short-lived proteins that may be attributed to their internal regional structure. The p57 KIP2 Protein Interactions: Comparison with p21CIP1/WAF1 and p27KIP1 p57KIP2 binds with CDKs in a cyclin-dependent manner (12). Association of p57KIP2, with cyclins only, is very weak. p57KIP2 inhibits in vitro the activity of the following CDKcyclin complexes: CDK2-cyclin E, CDK2-cyclin A, CDK3cyclin E, CDK4-cyclin D1, CDK4-cyclin D2, and to a lesser extent CDK1(CDC2)-cyclin B and CDK6-cyclin D2 (11, 12, 28). At low concentrations p57KIP2 can form active complexes with CDK2-cyclin A, enhancing their assembly, whereas at higher levels p57KIP2 inhibits the kinase activity of CDK2 (29). Similarly, CDK4-cyclin D1-heterodimer formation and activity is regulated in a p57 KIP2 dose-dependent manner (28). This property is in accordance with the ability of both p21CIP1/WAF1 and p27KIP1, at low concentrations, to promote FIGURE 2. Imprinting control regions of 11p15.5. The human chromosomal region 11p15.5 encompasses the H19-ICR (ICR-1) and the KCNQ1/KvDMRICR (ICR-2). H19-ICR is responsible for the imprinting status of several genes located in the telomeric end of 11p15.5 including H19 and IGF2. It is imprinted in the paternal allele (orange-dotted box), leading to the activation of the paternal IGF2 and to the suppression of the maternal H19. KCNQ1/KvDMR-ICR is located within intron 10 of the KCNQ1 gene in the promoter region of a noncoding antisense transcript named KCNQ1OT1/KvLQT1AS/LIT1. KCNQ1/KvDMRICR affects the imprinting status of the centromeric region of 11p15.5. The imprinting of the maternal ICR-2 (orange-dotted box) is associated with the suppression of the maternal LIT1 and the expression of the maternal genes p57KIP2 and KCNQ1. The arrows and the green boxes depict the active alleles, whereas the red boxes show the silent alleles. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review FIGURE 3. Methylation analysis of p57KIP2 promoter in normal and tumor human lung specimens. A. Methylation-specific PCR analysis shows promoter methylation in both normal (N) and tumor (T) lung tissue in a representative case. M+ and M- denote the methylation-specific PCR analysis with primers designed to bind specifically to methylated and nonmethylated CpG islands, correspondingly. B. Pyrosequencing analysis of the same representative case (depicted in A), showing decreased promoter methylation [assayed as methylation index (MtI)] in the tumor (T) versus the corresponding normal (N) tissue. Note the different scale in the y-axis of the pyrosequencing diagram. the assembly of CDK4-cyclin D complex, whereas at higher levels to abrogate the kinase activity of the CDK-cyclin heterodimers (30-32). The amino-terminal region of CIP/KIP members is necessary and sufficient for the inhibition of CDK-cyclin activity. It consists of three sites that are involved in the suppression of CDK-cyclin activity, a cyclin binding region, a CDK binding site, and a 310 helix (Fig. 1B). The 310 helix contains a phenylalanine-tyrosine pair of amino acids that is bound to the aminoterminal of CDK2, inside the catalytic cleft, mimicking the purine base of adenosine triphosphate (24). The 310 helix is indispensable for the in vivo inhibition of CDK2-cyclin A and CDK2-cyclin E by p57KIP2, but not for p21CIP1/WAF1 and p27KIP1 (29). It has been proposed that the central region of p57KIP2 may serve as an important domain for protein interactions implicated in functions other than the CDK-inhibitory role (15). Indeed, the central region of mouse p57KIP2 interacts with the N-terminal of LIMK-1, a downstream effector of Rho (analyzed in the Cytoskeletal Organization section; ref. 33). The carboxy-terminus of p57KIP2 binds in vitro with proliferating cell nuclear antigen (PCNA) with a much lower affinity than p21CIP1/WAF1 (34). In addition, p57KIP2 interacts with and inhibits the kinase activity of c-Jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) through its QT domain (35). Interestingly, p27KIP1 does not inhibit JNK/SAPK activity, although it contains a QT domain (35). p21CIP1/WAF1 also has the ability to bind and suppress the activity of JNK/SAPK via the amino-terminal domain (36). p57KIP2, but not p21CIP1/WAF1 or p27KIP1, interacts both in vivo and in vitro through its amino-terminal domain with the transcription factor B-Myb (37). B-Myb competes with Cyclin A2 for the association with p57KIP2. Overexpression of B-Myb partially overwhelms the G1 cell cycle arrest induced by p57KIP2 in Saos-2 cells. Expression and Tissue Distribution Pattern of p57KIP2 A highly cell-specific, temporal and spatial p57KIP2 expression profile has been found during the fetal, the postnatal, up to puberty, and the adult life cycle. Most of the data have been obtained from rodents (14, 38-44) and only sporadically in humans (11, 12, 44, 45). Specifically, the highest levels and most widespread tissue localization were observed during organogenesis. p57KIP2 is present in all major organs during embryonic development, and its levels of expression peaks at key stages of differentiation for each specific organ (14, 39, 41). Afterward, its expression declines to low or undetectable levels in several tissues (14, 39, 41), and only organs that mature after birth, such as testis (44), exhibit strong p57KIP2 staining in Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1905 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1906 Pateras et al. certain tissue compartments. Comparatively to prenatal tissues, fewer adult tissues continue to abundantly express p57KIP2 (11, 12). Nevertheless, an age-dependent p57KIP2 decline in some of these tissues has also been reported (42). Human adult tissues expressing significant p57KIP2 mRNA levels are mainly skeletal muscle, brain, heart, lung, kidney, pancreas, testis, and placenta (11, 12); this is in contrast with the wider tissue distribution of higher levels of human p21 CIP1/WAF1 and p27 KI P1 mRNA (11, 12). In rodents, p57KIP2 expression correlates, on average, with the human distribution pattern (12, 14, 39, 41), but a few species-specific exceptions do exist (14, 39, 41, 44). Regulation of p57KIP2 Transcriptional Regulation of p57KIP2 Epigenetic control has emerged as an important mechanism for the transcriptional regulation of p57KIP2. The genetic locus of human p57KIP2, 11p15.5, harbors several imprinted genes (Fig. 2). Genomic imprinting refers to the differential epigenetic modulation of a gene leading to a parent-of-origin specific expression. This term means that the maternal and paternal allele of an imprinted gene display different properties, despite the fact that they have identical sequences. Epigenetic mechanisms include modulations of DNA methylation within CpG islands, chromatin remodeling (covalent modifications of histones), and silencing from various types of noncoding RNA transcripts (46). Methylation of DNA within CpG doublets, as well as methylation and deacetylation, in the aminoterminal tails of histones H3 and H4 are related with an inactive gene state, whereas the opposite is associated with gene activation. The cluster of imprinted genes in specific chromosomal regions, suggests that they share a common regulatory mechanism. The imprinting of such clusters is regulated by specific sequences acting in cis, known as imprinted control regions (ICR). ICRs encompass the following features: (i) a differentially methylated region (DMR) and chromatin conformation status between the maternal and the paternal genome and (ii) the establishment of the imprinting marks during gametogenesis, because this is the only developmental period in which the maternal and paternal genome are separated (47, 48). The linkage of genes within the 11p15.5 region and the mouse homolog on distal chromosome 7 is conserved, showing the significance of the integrity of this region for the proper imprinting of the genes located therein (49-51). The regulation of imprinted genes in 11p15.5 is controlled by two ICRs, H19-ICR (ICR1) and KCNQ1/KvDMR-ICR (ICR2; Fig. 2). H19-ICR is located in the telomeric end of 11p15.5 and influences the imprinting of H19 and IGF2 by functioning as a chromatin insulator, restricting the access to shared enhancers (52). H19 is maternally expressed, whereas IGF2 is paternally transcribed. The KCNQ1-ICR coordinates the imprinting status of the more centromeric domain of 11p15.5 encompassing p57KIP2 and KCNQ1/KvLQT1 (53-56). p57KIP2 is maternally expressed, however there is a leaky expression from the paternal allele in most human tissues (57). The imprinted status of p57KIP2 is conserved between mice and human (13). p57KIP2 is hypomethylated in normal human kidneys (58), whereas we showed promoter methylation in normal human bronchial tissue (Fig. 3; ref. 59), suggesting the involvement of tissue-specific FIGURE 4. Multiple roles of p57KIP2 in cell biology. A. Positive p57KIP2 immunostaining in mitosis (arrowhead) and in the nucleus (arrows) in the cancerous region of a representative case. B. Positive cytoplasmic p57 KIP2 immunostaining of a cancer cell (arrowhead) from a representative case. C. Putative role of p57KIP2 in apoptosis and senescence. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review FIGURE 5. p57KIP2 has a vital role in development. p57KIP2−/− mice have increased postnatal lethality and exhibit severe developmental defects in comparison with p21CIP1/WAF1−/− and p27KIP1−/− mice. mechanisms in the imprinting control of p57KIP2. Treatment with 5′-azacytidine, a demethylating agent, and/or trichostatin, a histone deacetylase inhibitor, activates p57KIP2 expression in mouse embryo fibroblasts, showing that both CpG methylation and histone deacetylase activities are involved in p57KIP2 imprinting (60). KCNQ1 is maternally expressed and harbors in intron 10 an antisense orientated nontranslated transcript named KCNQ1OT1/KvLQT1AS/LIT1 (long QT intronic transcript 1), which is paternally expressed (53-55). The KCNQ1-ICR coincides with the promoter of LIT1 in both human and mice (Fig. 2; refs. 53, 55, 61). The KCNQ1-ICR encompasses the typical characteristics of an ICR; it carries DNA methylation and acquires a repressive chromatin structure on the maternal allele, and the imprinting marking is established from the female germline (53-55, 62-64). The imprinting status of KCNQ1-ICR is associated with the expression pattern of the centromeric genes of 11p15.5, including p57 KIP2 . Specific regulatory elements within or in the flanking region of the KCNQ1 gene possibly act at a distance and regulate the expression of p57KIP2 according to the imprinting status of KCNQ1-ICR (6570). The disruption of p57KIP2 imprinting in p57KIP2 transgenic lines supports the significance of cis-elements that are important for p57KIP2 expression lying at distance from the gene (71, 72). A functional role for LIT1 is also supported, participating in the establishment of the imprinting status of p57KIP2 (73-75), similar to the function of Xist on X chromosome inactivation (76) and of the noncoding Air on the IGF2R locus (77). In marsupials LIT1 is expressed in the absence of p57KIP2 imprinting, suggesting a step-by-step evolutionary accumulation of these epigenetic mechanisms within the p57KIP2 region (78, 79). Recently, a series of micro-RNAs (miR) have been reported to down-regulate the expression of p57KIP2, either specifically or along with other CIP/KIP members. Particularly, miR-221 and miR-222, which belong to the same cluster, are known from bioinformatic analyses to target both p57KIP2 and p57KIP2 (80-82). This effect has been validated in various human cell lines and in vivo in human hepatocellular and gastric carcinomas (80-83). In gastric cancer, p57KIP2 expression is also regulated by miR-25 (81), whereas in human embryonic stem cells it is specifically targeted by miR-92b (84). Functional analyses have shown that miR-dependent CIP/KIP silencing results in a shift in the number of cells from G1 to S-phase (80-82, 84). In murine embryonic stem cells and neural stem cells derived from embryonic stem cells, miR-106b and miR-17-92 suppress p57KIP2 and p21CIP1/WAF1 and promote renewal of these stem cells (85). Numerous other pathways control the expression of p57KIP2, possibly through activation of epigenetic mechanisms. In this context, the proteins SMARCB1 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily b, member 1) and CITP2 (chicken ovalbumin upstream promoter transcription factor interacting protein 2) up-regulate and correspondingly suppress p57KIP2 expression through chromatin remodeling (86, 87). Histone methyltransferase EZH2 can suppress p57KIP2 through histone H3 lysine 27 trimethylation (H3K27me3; ref. 88). Histone deacetylase inhibitors enhance the recruitment of Sp1 transcription factor in the promoter of p57KIP2, inducing its expression (89). The p53-related family member p73β induces the expression of p57KIP2 by activating the transcription of the nonsilent maternal allele (90). Interestingly, it was found that p73β isoform up-regulates the expression of both p57KIP2 and KCNQ1 without affecting the status of LIT1. p53 failed to induce p57KIP2, although it transcriptionally activates p21CIP1/WAF1 (12, 90, 91). The fact that p57KIP2−/− mice share a similar phenotype with p63−/− mice prompted Beretta and colleagues (17) to examine the possibility of a link between these two proteins. Indeed, the p63 isoform ΔNp63α binds to p57KIP2 promoter and induces its activation (17). The CDK inhibitor BMS-387032 up-regulates p57KIP2 through the transcriptional factor E2F1 in a direct manner (92). Induction of p57KIP2 after drug treatment, in turn, restrains E2F1 activity, Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1907 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1908 Pateras et al. serving as a negative feedback loop. Transforming growth factor β1 (TGFβ1) induces p57KIP2 in human hematopoietic cells, leading to cell cycle arrest (93). Silencing of p57KIP2 abrogates the TGFβ1- induced decrease in proliferation of primary human limbal epithelial cells (94). TGFβ induces p27KIP1 and p21CIP1/WAF1 as well (95, 96). Insulin-like growth factor 2 (IGF2) down-regulates p57KIP2 in vivo in a dose-dependent manner (97). The Notch effectors Hes1 and Herp2 bind to and suppress the expression of p57KIP2 (18, 19). Hes1 also directly suppresses the expression of p27KIP1 (98). p57KIP2, but not p21CIP1/WAF1 or p27KIP1, is induced by the transcription factor E47 that participates in human development, consistent with the unique role of this member of CIP/KIP family in embryogenesis (analyzed below; ref. 99). Interestingly, inhibitor of differentiation 2 (Id2), a natural inhibitor of E47, suppresses p57KIP2. The chimeric protein PAX3-FOXO1, often present in rhabdomyosarcoma, reduces p57KIP2 expression via the repression of the GC box-binding factor EGR1 (100). PLAG1/ZAC1 is an imprinted gene selectively expressed from the paternal allele from chromosomal region 6q24 (101). It has been shown that ZAC1 affects the expression of p57KIP2 (101, 102). Human and mouse p57KIP2 promoter contains a functional glucocorticoid response element (20). The induction of p57KIP2 upon glucocorticoid treatment may be responsible for the antiproliferative effects of glucocorticoids (103). The antigrowth effect of atrial natriuretic peptide may be partially mediated by the fact that it induces p57KIP2 and p27KIP1 as well (104). The vitamin D3 analog EB1089 inhibits the proliferation of the human laryngeal squamous cell carcinoma (Hep-2) through the induction of p57KIP2 (105). Kido and colleagues (106) have shown that exon-2 of p57KIP2 encompasses a functional Bel1 response element, activated by the Bel1 transactivator of the human foamy virus. Post-translational Regulation of p57KIP2 Ubiquitylation and subsequent proteasomal degradation play a significant role in the regulation of p57KIP2 protein levels. The SKP1-CUL1-F-box (SCF) complex is part of the ubiquitin-proteasome pathway and mediates ubiquitylation of target proteins from late G1 to early M phase. It consists of three constant subunits, named SKP1, CUL1, and RBX1, and a variable FIGURE 6. Multiple epigenetic and genetic defects in the 11p15.5 chromosomal region are responsible for the phenotypic heterogeneity of Beckwith-Wiedemann Syndrome. Loss of imprinting of ICR-2 leading to the silencing of the p57KIP2 gene accounts for the majority of cases with BWS. Uniparental disomy 11 (UPD11) represents a genetic abnormality because of abnormal chromosomal recombination leading to double dose of IGF2 and suppression of p57KIP2. Loss of imprinting of ICR-1 causing double dose of IGF2 is a less frequent event in comparison with loss of imprinting of ICR-2 in BWS. Mutations in p57KIP2, located mainly in the CDKinhibitory or in the QT box/PCNA-binding domain, are implicated in the pathogenesis of BWS. In this figure we present the four most frequent mechanisms related to the pathogenesis of BWS. The sum of all above percentages is less than 100%, as other mechanisms (most of them are still unknown) are also responsible for the pathogenesis of BWS. The arrows and the green boxes denote active genes, whereas the red boxes show inactive genes. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review Table 1. Summary of the Results from the In vivo Studies of p57KIP2 Aberrations in Several Types of Cancer Type of Cancer Alterations in p57KIP2 References KIP2 No mutations, frequent LOH in 11p15.5 (with a maternal bias) associated with decreased p57 mRNA; reactivation of the paternal p57KIP2 (LOI) in tumors with LOH; p57KIP2 expression varies Soft tissue sarcomas No mutations Hepatoblastoma No mutations; LOH with a maternal bias; increased mRNA expression of p57KIP2 ALL, LMB ALL: Downregulation of p57KIP2 (increased methylation of p57KIP2 promoter is partially associated with its decreased expression); AML: increased methylation of p57KIP2 promoter; LMB: no mutations, increased methylation of p57KIP2 promoter AC and GBM AC: no mutations; GBM: decreased expression of p57KIP2 Oral squamous cell carcinoma No mutations; LOH with no parental bias; increased mRNA expression in cases with LOI; decreased positive immunostaining of p57KIP2 protein Laryngeal squamous cell carcinoma Decreased positive immunostaining of p57KIP2 protein Lung carcinomas No mutations; frequent LOH with a maternal allele bias; increased methylation of p57KIP2 promoter (non-small cell lung carcinomas) (and in a few cases upregulation of LIT1) related with decreased expression of p57KIP2; faint p57KIP2 positive immunostaining in tumor versus normal tissues; diminished p57KIP2 protein status associated with increased SKP2 Esophageal squamous carcinoma p57KIP2-positive immunostaining at relatively high frequency in tumors Gastric carcinoma No mutations; increased levels of miR-25, miR-221, and miR-222 (target p57KIP2) PC and IPMN PC: p57KIP2-positive immunostaining decreases in cases with high biologic aggressiveness; IPMN: Decreased transcriptional and translational levels of p57KIP2 associated with promoter hypermethylation. A subset of specimens exhibited LIT1 hypomethylation because of deletion of the methylated LIT1 allele. HC and EIC HC: no mutations; downregulation of p57KIP2 related to loss of LIT1-ICR methylation; reduced positive immunostaining of p57KIP2 in cases with high biological aggressiveness; downregulation of p57KIP2 protein associated with upregulation of miR-221; EIC: Decreased expression of p57KIP2 in cases with biological aggressive phenotype; Colorectal carcinoma Decreased positive immunostaining of p57KIP2 in colorectal carcinomas Bladder carcinoma No mutations; diminished expression of p57KIP2 mRNA correlated in some cases with LOH; decreased expression of p57KIP2 positive immunostaining Breast carcinoma No mutations; Increased methylation of p57KIP2 promoter; decreased transcriptional levels and diminished positive immunostaining of p57KIP2 Ovarian carcinoma Intense positive immunostaining of p57KIP2; decreased positive immunostaining in cases with high biological aggressive phenotype Malignant adrenocortical tumors Reduced mRNA expression of p57KIP2 Thyroid carcinomas Decreased p57KIP2 positive immunostaining in cases with biological aggressive phenotype Wilms' tumor 58, 212-217 213 218 ALL: 219-222; AML: 16; LMB: 223 126, 211 224, 225 226 59, 227, 228 246 81, 229 PC: 231, 230; IPMN: 247 HC: 15, 80, 232-236; EIC: 237 248 15, 238, 239, 249 15, 88, 227, 240 241, 242 243, 244 245 Abbreviations: AC, astrocytoma; ALL, acute lymphocytic leukemia; AML, acute myelogenous leukemia; EIC, extrahepatic bile duct carcinoma and intrahepatic cholangiocellular carcinoma; GBM, glioblastoma; HC, hepatocellular carcinoma; IPMN, intraductal papillary mucinous neoplasm; LMB, lymphoid malignancies of B-cell origin; LOH, loss of heterozygosity; LOI, loss of imprinting; PC, pancreatic carcinoma. component, an F-box protein that determines the target protein (107). The S-phase kinase-associated protein 2 (SKP2) belongs to F-box proteins. SKP2 interacts with p57KIP2 and promotes its degradation in a phosphorylation-dependent manner (108). SKP2 also mediates the degradation of p21 CIP1/WAF1 and p27KIP1 (107). TGFβ1 stimulation induces p57KIP2 degradation via Smad-mediated transcription in serum-starved mouse osteoblasts (109, 110). TGFβ1 up-regulates the expression of a novel F-box protein, called FBL12, responsible for the mediation of p57KIP2 degradation in a SKP2-independent manner in osteoblast cells and 293T cells originating from human kidney (111). The fact that TGFβ1 induces p57KIP2 in human hematopoietic and limbal epithelial cells may reflect tissue-specific regulation of p57KIP2 or alternatively reveal different regulatory mechanisms between mice and humans (93, 94). A recent study showed that p57KIP2 participates in the TGFβ-compensatory tubular hypertrophy in unilaterally nephrectomized male Sprague-Dawley rats, suggesting a positive correlation between TGFβ and p57KIP2 in this type of tissue (112). Functions of p57KIP2 Cell Cycle Control The role of the CDK inhibitors p21CIP1/WAF1 and p27KIP1 in cell cycle arrest is well established (96, 113). In accordance with the other CIP/KIP family members, induction of p57KIP2 causes cell cycle arrest in G1 phase (11, 12). Transfection of SAOS-2 (sarcoma osteogenic, p53−/−, and Rb−/−) cells with the full-length p57KIP2 and a truncated p57KIP2, in which the carboxy-terminal is omitted, led to G1 arrest (12). This finding is in agreement with the fact that the amino-terminal of p57KIP2 is indispensable for cell cycle arrest, through the inhibition of activity of the Cyclin-CDK complexes. In accordance with the above, induction of p57KIP2 in R-1B/L17 (subclone of the Mv1Lu mink lung epithelial cell line) caused cell cycle arrest in G1 phase (12). Endoreduplications are successive oscillations of G and S phases in the absence of mitosis and cytokinesis (114). The protein levels of p57KIP2 alter periodically during subsequent endoreduplications of trophoblast giant cells, diminishing before S-entry and reappearing after the completion of S phase (115). Introduction of a stable form of p57KIP2 into trophoblast giant cells blocks G1- to S-phase transition (115). A role of p57KIP2 in endoreduplication is reinforced by the fact that p57KIP2 triggers endoreduplication in mouse trophoblast stem cells by suppression of CDK1 activity (116). In the same study, p21CIP1/WAF1 and p27KIP1 could not compensate p57KIP2 for its role in endoreduplication in trophoblast stem cells. Moreover, p57KIP2 participates in the M-to-G1 transition through activation by p73 (100). Abrogation of p73 or its downstream effector p57 KIP2 perturbs mitotic progression and transition to G1 phase (Fig. 4A; ref. 117). Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1909 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1910 Pateras et al. Cytoskeletal Organization p57KIP2 has a nuclear distribution, consistent with its antiproliferative capacity (11). However, it has been shown that p57KIP2 may accumulate in the cytoplasm participating in the regulation of the cytoskeletal dynamics (33). Mouse p57KIP2 binds, through its central domain, to LIM-kinase-1 and translocates it from the cytoplasm to the nucleus, without abrogating its kinase activity. LIM-kinase-1 is a serine-threonine kinase that phosphorylates and inactivates an actin depolymerization factor cofilin, leading to the stabilization of actin stress fibers (118). Our laboratory provided evidence for the specificity of human cytoplasmic p57KIP2 localization in normal and cancerous material from lung (Fig. 4B; ref. 59). p21CIP1/WAF1 and p27KIP1 also have a distinct function in the cytoplasm, different form the cyclin-CDK inhibitory role. They have the ability to regulate the Rho signaling pathway, therefore interfering with cytoskeletal organization (119). Altogether it seems that the CIP/KIP members participate in the interconnection between cell cycle control and cytoskeletal organization. Putative Role of p57KIP2 in Apoptosis and Senescence p57 KIP2 enhances staurosporine-induced apoptosis in human cervical adenocarcinoma cell line (HeLa) cells in a CDK-inhibitory independent manner (120). p57KIP2 translocates to mitochondria and activates the intrinsic apoptotic pathway (121). Targeted silencing of p57KIP2 suppresses the p73β-mediated apoptosis in the lung cancer cell line H1299 and in the colorectal carcinoma cell line HCT116 caused by cisplatin treatment (122). Upregulation of p73β in postmitotic hNT neurons induces p57KIP2 and BAX leading to apoptosis (123). In contrast, p57KIP2 suppresses JNK/SAPK mediated apoptosis in the human embryonic kidney cell line HEK293 after exposure to UV light, demonstrating an anti-apoptotic role of p57KIP2 (35). Similarly, induction of p57KIP2 by BMS387032 has a strong antiapoptotic effect on the MDAMB-231 cell line (92). A dual role in apoptosis has been documented for p27 KIP1 and p21CIP1/WAF1, although most reports confer, especially for p21CIP1/WAF1, an anti-apoptotic role (95, 119, 124). We have not found an association of p57KIP2 or p27KIP1 with apoptosis neither in vivo in non-small cell lung cancer specimens nor in vitro in the A549 lung cancer cell line (59, 125). The role of CIP/KIP members in apoptosis may be tissue specific, dependent on the intracellular localization and the pathway they target (Fig. 4C). CIP/KIP members also play a role in cellular senescence. The induction of p57KIP2 in human astrocytoma cell lines restrains their proliferation and induces a senescent phenotype (126). Similarly, upregulation of p57KIP2 in the PPC-1 prostate cancer cell line induces a senescence-like phenotype (127). However, more studies are required to clarify the relation of p57KIP2 with cellular senescence (Fig. 4C), in contrast to the well-established role of p21CIP1/WAF1 (96). Lessons from Mice Mice lacking p57KIP2 (p57KIP2−/−) display increased postnatal mortality accompanied by severe developmental abnormalities (Fig. 5; refs. 128-130). Mice with targeted disruption of p57KIP2 exhibit limb shortening owing to abnormal endochondral ossification, cleft palate, omphalocoele, gastrointestinal tract defects, adrenal cortex enlargement, renal medullary dysplasia, abnormalities in lens fiber cells, and increased body weight (128-131). Surviving mice exhibited severe growth retardation, immaturity of testes and uterus, and vaginal atresia (130). Mice with targeted deletion of the maternal p57KIP2 allele showed similar phenotypic abnormalities with p57KIP2−/− mice (128, 129). The observed developmental defects occur possibly because of delayed differentiation and increased apoptosis. Excess p57KIP2 in mice leads to increased embryonic lethality and to decreased body size, suggesting that embryonic growth is sensitive to p57KIP2 dosage (131). Endochondral bone formation is compromised in null mice for either parathyroid hormone-related peptide (PTHrP) or p57 KIP2 , in an opposite manner (128, 129, 132, 133). In PTHrP/p57KIP2-null mice, the absence of p57KIP2 partially normalizes the PTHrP-null phenotype (133). Mutant mice lacking either both p57KIP2 alleles or only the maternal one, with the paternal allele intact, display severe placental abnormalities including trophoblastic dysplasia (134). Diminution of p57KIP2 expression in mouse placenta did not alter the activity of both CDK2 and CDK4, providing evidence for a biological role of p57KIP2 in placenta, different from the inhibition of the CDK activity. p21CIP1/WAF1 knockout mice (135, 136) and p27KIP1 null mice (137-139) do not exhibit gross developmental abnormalities, revealing the importance of p57KIP2 in embryonic development in relation with the other CIP/KIP members (Fig. 5). Interestingly, mice lacking both p21CIP1/WAF1 and p57KIP2 exhibit all the phenotypic alterations caused by p57KIP2 null mice alone, but also express novel abnormalities in lung, skeleton, and skeletal muscles, demonstrating the cooperation between these proteins in mouse development (38). The frequency of embryonic lethality increases in p57 KIP2 and p27 KIP1 double null mice compared with p27 KIP1−/+ p57 KIP2P+/M− (140). Moreover, p27 KIP1−/− and p57KIP2−/− mice exhibit more severe developmental defects in placenta and lenses than p27KIP1−/− mice alone, showing the significance of p57KIP2 in development. Immunohistochemical analysis of p57KIP2 and p27KIP1 in certain tissues from mice revealed a mutual pattern of expression, suggesting the importance of both KIPs for proper development (39). Susaki and colleagues (141) created a knock-in mouse model in which the p57KIP2 gene was replaced with p27KIP1 gene. In this model the mice are viable and phenotypically healthy, revealing the partial functional redundancy between the KIP members. The Role of p57KIP2 in Cooperation with p21CIP1/WAF1 and p27KIP1 in Development The fact that p57KIP2 is expressed during mouse embryogenesis in several anatomical structures underlies its role in embryonic development (128, 129). Specifically, p57KIP2 is found in derivatives of all three germ layers, the ectoderm, mesoderm, and endoderm, and in all major organs of the developing fetus (14, 39, 41). The earliest expression in rodents is between E9.0 and E10.5 in the heart (14, 39, 41). As mentioned above in the Expression and Tissue Distribution Pattern of p57KIP2 section, the highest p57KIP2 expression coincides with the stage of differentiation for each specific organ (14, 39, 41). Importantly, the strongest p57KIP2 expression appears at the interface of developing tissues with different embryonic origin, as in the direct contact between epithelial and mesenchymal Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review tissues (41). Comparative analyses of all three CIP/KIP family members during rodent prenatal development have revealed a complex spatial and temporal pattern of expression (38-40, 43, 140). Of note, cyclin D3, a p57KIP2 inhibition target, also exhibits a specific temporal and spatial expression pattern in differentiating mammalian tissues, as well as in relation to the other cyclin D members (142). Yet, with a few exceptions, no systematic correlation has been done with the corresponding p57KIP2 temporal and spatial pattern of expression. p57KIP2 cooperates with negative (p27KIP1) and positive (CDK2, CDK4, cyclin D, and cyclin E) cell cycle regulators to promote lens fiber differentiation (140, 143, 144). Particularly, it has an opposite effect on the proliferating function of cyclin D3 (144). p57KIP2 and p27KIP1 participate in mouse retina development through the induction of cell cycle exit in the retinal progenitor cells, but in mutually different subpopulations (145). Downregulation of p57KIP2 and p27KIP1, through Notch signaling, inhibits mouse lens epithelia differentiation (19, 146). p57KIP2 has two distinct roles in mouse retina, it controls proliferation of progenitor cells and promotes the development of amacrine interneurons (147). In addition, p57KIP2 promotes cell cycle exit of precursor cells in zebrafish retina through its activation by the Sonic hedgehog (Shh; ref. 148). p57KIP2 participates in the development of the nervous system (149). It collaborates with p27KIP1 on the regulation of neuronal migration of mouse cortex (150) and rat neurogenesis (151); it promotes oligodendrocyte differentiation (152, 153); and is required for the maturation of dopamine neurons (154). Downregulation of p57KIP2 mediates in vitro myelination by Schwann cells (155). p57KIP2 participates in myogenesis (38). It stabilizes MyoD, a muscle-specific transcription factor involved in myogenic differentiation, through the inhibition of the phosphorylationdependent degradation by cyclin E-CDK2 complex and by direct association of the amino-terminal domain of p57KIP2 with the basic helix-loop-helix domain of MyoD (156-158). In turn, MyoD up-regulates p57KIP2 in a p73-dependent manner (159). MyoD induces p21CIP1/WAF1 in a direct manner (158). Notably, cyclin D3 also participates in striated muscle cell differentiation (142), but no link has been established with p57KIP2. Interestingly, as podocytes progress to terminal differentiation they are characterized by an increase in both p57KIP2 and cyclin D3, along with a decrease in the levels of cyclin D1 (160). Differential immunohistochemical staining of p57KIP2 in human placenta cells suggests a role of p57KIP2 in human placenta development (161). The coordinated expression of the CIP/KIP members promotes keratinocyte differentiation (162, 163). During pancreatic development p57KIP2 controls both self-renewal and cell cycle exit of pancreatic progenitors (18). p57KIP2 and p27KIP1 cooperate in a temporal manner for pituitary development; p57KIP2 promotes cell cycle exit of progenitors, whereas p27KIP1 prevents cell cycle reentry (164). p57KIP2 is also implicated in hepatocyte maturation (40), T-lymphocyte cell development (165), spermatogenesis and Leydig cell development (45), hematopoiesis and hematopoietic stem cell cycle arrest (93, 166), chondrocyte differentiation (133, 167), and in adrenal cortex development (168). Overall, CIP/KIP members possibly share partial overlapping roles in embryogenesis, although p57KIP2 seems to have the upper hand over p21CIP1/WAF1 and p27KIP1 in development. The strong impact of p57KIP2 on embryo survival and development, along with its more complex internal structure relative to its counterparts, which seems to keep differentiated organs under control postnatally and in adulthood, implies that p57KIP2 may have preceded the appearance of the other CIP/KIP members evolutionarily. p57KIP2 in Pathology We analyze here the impact of p57KIP2 on human pathology, apart from its role in carcinogenesis, which is examined separately below in the Role of p57KIP2 in Carcinogenesis section. Several studies have shown the role of p57KIP2 in the pathogenesis of Beckwith-Wiedemann Syndrome (BWS; ref. 169). BWS is a clinically heterogeneous disease, with most patients exhibiting macrosomia, macroglossia, omphalocoele, and a predisposition to pediatric tumors, including Wilms' tumor, hepatoblastoma, adrenocortical carcinoma, and rhabdomyosarcoma (170). The phenotypic heterogeneity of BWS reflects the different epigenetic and genetic defects affecting the 11p15.5 domain (Fig. 6; refs. 171-174). The most frequent alteration is loss of imprinting of the maternal LIT1 locus (ICR-2), leading to biallelic expression of LIT1, which is associated with reduced levels of p57KIP2 (53-55, 62, 173, 175, 176). Epigenetic alterations in H19-ICR, related with upregulation of IGF2, is a less frequent event (177). Patients with BWS exhibit mutations of p57KIP2, more frequently seen in familial BWS (30–50%), than in sporadic BWS (5–10%; ref. 177). p57KIP2 mutations are mainly detected in the CDK-inhibitory domain and in the QT box domain (172, 173, 178-182). Mutations in the CDKinhibitory domain abrogate the CDK2-inhibitory activity, whereas mutations in the QT box domain retain the capability of CDK2 suppression, but exclude the protein from the nucleus, therefore in both cases the cell cycle inhibitory activity is compromised (181, 182). Mosaicism of paternal isodisomy of 11p15.5 [paternal uniparental disomy 11 (pUPD11)], accounts for almost 20% of BWS cases (177). Uniparental disomy results from chromosomal rearrangements owing to abnormal recombinations occurring in meiosis, mitosis, or successive meiosis and mitosis (183). Tissues employing pUPD11, have two paternal but no maternal copies of 11p15.5, exhibiting double dose of the growth-promoting paternally expressed IGF2 and diminished expression of the growth-inhibiting maternally expressed gene p57KIP2 (46, 184). The existence of a predominant pUPD11 distribution in the abdominal organs of two fetuses with BWS exhibiting omphalocoele (185) is reminiscent of the p57KIP2−/− phenotype in mice (129). Double mutant mice with loss of function of p57KIP2 and with gain of function of IGF2, mimicking pUPD11, display several similarities with BWS phenotype (186). Mutant mice, defective only for the maternal p57KIP2 allele (p57KIP2-M/+P), display the whole spectrum of the clinical manifestations of pre-eclampsia including proteinuria and elevated blood pressure (134, 187). The observed trophoblastic hyperplasia may be the leading cause (188). Further studies, failed to recapitulate pre-eclampsia manifestations in the particular Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1911 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1912 Pateras et al. mouse model, although they invariably exhibited placenta abnormalities, suggesting the significance of environmental factors in the development of this disease (188, 189). Recently, Romanelli and colleagues (190) reported the existence of three women with haemolysis, elevated liver enzymes, and low platelets (HELLP)-preeclampsia who gave birth to children with BWS possessing mutations in p57KIP2. Therefore, a possible role of the imprinted gene p57KIP2 in the pathogenesis of preeclampsia is suspected, although further studies are needed to clarify this issue. p57KIP2 is absent in androgenetic complete hydatidiform moles, an abnormality of the trophoblast proliferation, in which the total genome of the fetus is paternally derived (161). Therefore, p57KIP2 has been shown to be a highly sensitive marker for the differential diagnosis of complete from partial hydatidiform mole (191-197). Evidence supports a role for p57KIP2 in cardiovascular pathology. The expression of p57 KIP2 is increased, whereas p21CIP1/WAF1 and p27KIP1 decline in both acute and end-stage heart failure, reversing to the fetal pattern of expression (198). A microsatellite polymorphism, GTn repeat, positioned in the promoter region of p57KIP2 is related with atherosclerosis and myocardial infarction (199). The presence of the lower repeats was significantly more frequent among healthy individuals. Longer GTn repeats may lead to decreased transcription of p57KIP2, conferring increased susceptibility to atherosclerosis. Forced expression of p57KIP2 in cardiomyocytes from transgenic mice exerts a protective role from ischemia-reperfusion injury, possibly via the suppression of the JNK/SAPK pathway (200). p57KIP2 and p27KIP1 are decreased in damaged podocytes from patients with focal segmental glomerulosclerosis in comparison with controls (201). This finding is in agreement with previous studies in experimental models in mice and rat showing that p57KIP2 is suppressed in glomerular diseases (160). Of note, p57KIP2 downregulation is accompanied by a similar decrease in cyclin D3 and increase of cyclin D1 (160, 202). p57KIP2 seems to be involved in the pathogenesis of autosomal dominant polycystic kidney disease (203). Focal hyperinsulinism is caused by the absence of the maternal 11p chromosome (204). The fact that p57KIP2 is lost, whereas IGF2 is up-regulated in tissue specimens from patients with focal hyperinsulinism compared with controls, may explain the increased β-cell proliferation in focal hyperinsulinism (205). Role of p57KIP2 in Carcinogenesis Studies in Mice and Cell Lines Takahashi and colleagues (130) did not detect the development of spontaneous tumors during a 5-month observation period of p57KIP2 null mice. However, in p57KIP2−/− mice, 6 months postgrafting, the prostate grafted under the kidney capsule of athymic mice developed prostatic intraepithelial neoplasia, a precursor to prostatic cancer (206). Similarly, p21CIP1/WAF1−/− mice did not develop tumors until the 7th month of age, whereas after 16 months they were malignant prone (207). p27 KIP1−/− mice exhibit an increased risk of pituitary tumorigenesis (137-139). p57 KIP2 is down-regulated during immortalization of cultured human mammary epithelial cells (HMEC; ref. 208). The HMECs undergoing the immortal conversion initially lost the p57KIP2 maternal allele, associated with the upregulation of the previously silent allele; however, after adoption of the fully immortal phenotype, the remaining allele was also downregulated, but not lost. Ectopic expression of p57KIP2 in Ewing cells induces G1 arrest (21). p57KIP2−/− P-mouse embryo fibroblasts (P signifies parthenogenetic, exclusively comprising the maternal genome) exhibit increased proliferation in comparison with P-mouse embryo fibroblasts, where p57KIP2 is intact (209). We showed that restoration of p57KIP2 levels in A549 restrains cell cycle proliferation, without any significant effect on apoptosis (59). Similarly, exogenous expression of p57KIP2 in leukemia cells suppresses cell growth (210). Moreover, p57KIP2 induces apoptosis only in leukemia cell lines with methylated p57KIP2. p57KIP2-induced expression leads to the adoption of the senescence phenotype in astrocytoma cell lines and PPC-1 as mentioned earlier (126, 127). Overexpression of p57KIP2 reduces the invasiveness of U373 human malignant glioma cells independent of the extracellular matrix (211). p57KIP2 Is Frequently Down-regulated in Human Cancers through Several Mechanisms p57KIP2 is frequently down-regulated both transcriptionally and translationally in many human cancers, and its decreased expression is correlated with aggressiveness in several malignancies (Table 1; refs. 15, 16, 58, 59, 80, 81, 88, 126, 212-249). Two studies examining the p57KIP2 status in Wilms' tumor, show that p57KIP2 loss of heterozygosity was associated with reactivation of the silent allele (loss of imprinting), possibly reflecting the activation of a homeostatic feedback mechanism to prevent cell growth, similar with the p57 K I P2 expression pattern in the immortalization of HMECs (208, 215, 216). Similarly, the increased immunostaining of p57KIP2 in esophageal squamous cell carcinoma and its positive association with cyclin E and Ki-67 may reflect the activation of a feedback mechanism to limit the increased proliferation (246). In the same manner, in colorectal carcinogenesis p57KIP2 levels increase significantly from normal mucosa to adenomas and ultimately decrease in primary carcinoma (248). Downregulation of p57KIP2 is inversely correlated with proliferation in non-small cell lung carcinoma (59), in pancreatic adenocarcinoma (230), in hepatocellular carcinoma (234), in extrahepatic bile duct carcinoma, and intrahepatic cholangiocellular carcinoma (237). Diminished expression of p57KIP2 predicts poor prognosis in oral squamous cell carcinoma (225), in laryngeal squamous cell carcinoma (226), in hepatocellular carcinoma (234, 235), and in malignant ovarian tumors (242). Recently, Yang and colleagues (88) provided evidence that decreased p57KIP2 expression is related with poor outcome in breast cancer. The fact that we have not observed any association between p57KIP2 or p27KIP1 immunostaining status, respectively, and patient stage in non-small cell lung carcinoma suggests a relatively early inactivation of both KIP members in the development of this type of cancer (59). The above data, showing that p57KIP2 is increased in the initial stages of cancer followed by a gradual decrease as malignancy progresses, imply that a selective pressure leading to its loss takes place (59, 208, 246, 248). As we have previously shown, the DNA damage response (DDR) pathway, which is also activated from the earliest stages of cancer (250, 251), Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review seems to follow the same fate (252). Having in mind that p57 KIP2 is a target of p73β (90) and that DDR regulates p73β, as we have recently shown (253), it is tempting to speculate that p57KIP2 could represent an additional downstream DDR effector. Such a scenario should be further validated. No mutations of p57KIP2 have been found in all cancer specimens analyzed so far (Table 1). In accordance with p57KIP2, p21CIP1/WAF1 and p27KIP1 are rarely mutated in human cancers (96, 113). Therefore, other mechanisms are implicated in p57KIP2 downregulation in human cancers (Table 1). Our analysis on 70 matched normal tumor specimens from patients with non-small cell lung carcinoma revealed that multiple mechanisms lead to p57KIP2 downregulation in lung cancer (59). The majority of cases had decreased expression of p57KIP2, which was strongly associated with increased SKP2 levels and reduced transcriptional levels of p57KIP2. Increased methylation of p57KIP2 promoter and loss of heterozygosity were correlated with p57KIP2 mRNA downregulation. Aberrant methylation and histone modifications in the p57KIP2 locus seem to be a crucial mechanism for the inactivation of p57KIP2 in common malignancies (16). The reactivation of the p57KIP2 gene after treatment with demethylating agents and histone deacetylase inhibitor in many cancer cell lines denotes the significance of the epigenetic mechanisms in p57KIP2-downregulation in several human cancers (16, 59, 86, 89, 210, 223, 241, 249, 254-256). We showed that treatment of the A549 cell line with 5′-azacytidine, a demethylating agent, up-regulates p57KIP2 mRNA levels significantly, whereas the protein levels do not increase in a significant manner (59). Only demethylation along with SKP2 siRNA-silencing restored p57KIP2 protein levels in A549 cells. Interestingly, in our study, a subset of cases with increased p57KIP2 mRNA exhibited decreased p57KIP2 protein levels possibly because of the increased SKP2 levels. Therefore, it is essential to examine the p57KIP2 mRNA levels along with its protein status in order to clarify cumulatively the end effect from the demethylating agents on gene transcription and from p57KIP2 protein degradation in human cancer. It is possible that increased p57KIP2 mRNA expression, observed in some malignancies, may be counterbalanced by elevated p57KIP2 protein degradation (Table 1). In view of emerging molecular therapeutic approaches, aiming to restore the CIP/KIP activity in various malignancies, such collective information is crucial for their success (257). According to the imprinting pattern of LIT1 and p57KIP2, the expression status of these genes is inversely correlated. However, we did not observe a strong inverse relation between LIT1 and p57KIP2 expression, which is in accordance with the findings of Hoffmann and colleagues (249) in bladder carcinoma, Sato and colleagues (247) in pancreatic ductal neoplasms, and Nakano and colleagues (258) in several colorectal cancer cell lines. It is possible that LIT1 cooperates with several elements lying in the 11p15.5 region, in order to promote the proper imprinting of p57KIP2. The absence of a significant relationship between p57KIP2 and LIT1 expressional status may be due to the disruption of the integrity of the 11p15.5 region due to loss of heterozygosity, which is a frequent event in this chromosomal region in many cancers (259). Alternatively, this mechanism may be tissue specific. Soejima and colleagues (260) found that diminution of p57KIP2 in several human esophageal cancer cell lines was associated with the epigenetic status of LIT1 locus and not of its own promoter. A functional link between miRNA-25, miRNA-221 and miRNA-222, and p57KIP2 mRNA levels, mediating suppression of the latter, has been recently shown in HeLa; in MCF7 (human breast cancer cell line); in the human gastric cancer cell lines SNU-638, AGS, and MKN-28 (81); in K562 (human leukemic cell line); and in the T98G (human glioblastoma) cell line (82), as well as in vivo in human gastric and hepatocellular carcinomas (80, 81). It seems that p57KIP2 has a more clear-cut oncosuppressor activity in comparison with the other members of CIP/KIP family so far. p57KIP2 is frequently targeted in most cancers supporting its tumor-suppressor activity, however deductions about p57KIP2 function can be made only in the tissue context examined. Indeed, p21CIP1/WAF1 has both an oncogenic and a tumor-suppressor activity dependent on the tissue studied (96). Moreover, p27KIP1 harbors an oncogenic function when it is localized in the cytoplasm of many common tumors (119). The cytoplasmic localization of p57KIP2 in some cancers may introduce an oncogene-like behavior. However, the fact that cytoplasmic mouse p57KIP2 translocates LIMK1 from the cytoplasm to the nucleus, and that the elevated cytoplasmic LIMK1 promotes cancer invasion (261), supports a tumor-suppressor activity for cytoplasmic p57KIP2, although more studies are needed to clarify this issue. The examination of the unique central domain of p57KIP2, PAPA region, by Tokino and colleagues (15) resulted in an association of specific PAPA polymorphisms with breast cancer risk. However, in a subsequent analysis in a larger cohort by Li and colleagues (262), this correlation was not confirmed. Therefore, this issue remains unresolved and requires further investigation. Conclusion p57KIP2 has a distinct role in embryogenesis among CIP/KIP members. The increased mortality of p57KIP2 knockout mice denotes its impact on tissue development. The absence of mutations of p57KIP2 in all cancers studied so far implies the importance of the integrity of this gene for cell viability. The participation of p57KIP2 in cell cycle arrest and the identification of putative novel functions in endoreduplication, mitotic exit, apoptosis, senescence, and cytoskeletal organization highlight its significance in the context of its frequent downregulation in many human cancers. The effort to unravel the biology of p57KIP2 has already provided a useful diagnostic marker in the differential diagnosis of complete from partial hydatidiform moles. In the future, the putative antitumor functions of p57KIP2 may be exploited to design novel therapeutic agents for BWS and several common malignancies. Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed. Notes Added in Proof The following publications have come to our attention since the review entered the proof preparation. 1. Vlachos and Joseph reported that human p57KIP2 interacts in the cytoplasm with LIMK-1 enhancing its kinase activity, Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1913 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1914 Pateras et al. resulting in the inactivation of cofilin. They showed that the cytoplasmic localization of p57KIP2 negatively affects cell mobility, reinforcing the oncosuppressor activity of p57KIP2 in the cytoplasm (263). 2. Mascarenhas and colleagues depicted the involvement of p57KIP2 in hematopoietic development (264). 24. Russo AA, Jeffrey PD, Patten AK, Massague J, Pavletich NP. Crystal structure of the p27Kip1 cyclin-dependent-kinase inhibitor bound to the cyclin ACdk2 complex. Nature 1996;382:325–31. 25. Wright PE, Dyson HJ. Intrinsically unstructured proteins: re-assessing the protein structure-function paradigm. J Mol Biol 1999;293:321–31. 26. Brown CJ, Takayama S, Campen AM, et al. Evolutionary rate heterogeneity in proteins with long disordered regions. J Mol Evol 2002;55:104–10. 27. Dunker AK, Brown CJ, Lawson JD, Iakoucheva LM, Obradovic Z. Intrinsic disorder and protein function. Biochemistry 2002;41:6573–82. References 1. Lundberg AS, Weinberg RA. Control of the cell cycle and apoptosis. Eur J Cancer 1999;35:1886–94. 2. Serrano M, Hannon GJ, Beach D. A new regulatory motif in cell-cycle control causing specific inhibition of cyclin D/CDK4. Nature 1993;366:704–7. 3. Hannon GJ, Beach D. p15INK4B is a potential effector of TGF-β-induced cell cycle arrest. Nature 1994;371:257–61. 4. Guan KL, Jenkins CW, Li Y, et al. Growth suppression by p18, a p16INK4/ MTS1- and p14INK4B/MTS2-related CDK6 inhibitor, correlates with wild-type pRb function. Genes Dev 1994;8:2939–52. 5. Chan FK, Zhang J, Cheng L, Shapiro DN, Winoto A. Identification of human and mouse p19, a novel CDK4 and CDK6 inhibitor with homology to p16ink4. Mol Cell Biol 1995;15:2682–8. 6. Hirai H, Roussel MF, Kato JY, Ashmun RA, Sherr CJ. Novel INK4 proteins, p19 and p18, are specific inhibitors of the cyclin D-dependent kinases CDK4 and CDK6. Mol Cell Biol 1995;15:2672–81. 7. Harper JW, Adami GR, Wei N, Keyomarsi K, Elledge SJ. The p21 Cdkinteracting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases. Cell 1993;75:805–16. 8. Xiong Y, Hannon GJ, Zhang H, Casso D, Kobayashi R, Beach D. p21 is a universal inhibitor of cyclin kinases. Nature 1993;366:701–4. 9. Polyak K, Lee MH, Erdjument-Bromage H, et al. Cloning of p27Kip1, a cyclin-dependent kinase inhibitor and a potential mediator of extracellular antimitogenic signals. Cell 1994;78:59–66. 10. Toyoshima H, Hunter T. p27, a novel inhibitor of G1 cyclin-Cdk protein kinase activity, is related to p21. Cell 1994;78:67–74. 11. Lee MH, Reynisdottir I, Massague J. Cloning of p57KIP2, a cyclin-dependent kinase inhibitor with unique domain structure and tissue distribution. Genes Dev 1995;9:639–49. 12. Matsuoka S, Edwards MC, Bai C, et al. p57KIP2, a structurally distinct member of the p21CIP1 Cdk inhibitor family, is a candidate tumor suppressor gene. Genes Dev 1995;9:650–62. 13. Hatada I, Mukai T. Genomic imprinting of p57KIP2, a cyclin-dependent kinase inhibitor, in mouse. Nat Genet 1995;11:204–6. 14. Potikha T, Kassem S, Haber EP, Ariel I, Glaser B. p57Kip2 (cdkn1c): sequence, splice variants and unique temporal and spatial expression pattern in the rat pancreas. Lab Invest 2005;85:364–75. 15. Tokino T, Urano T, Furuhata T, et al. Characterization of the human p57KIP2 gene: alternative splicing, insertion/deletion polymorphisms in VNTR sequences in the coding region, and mutational analysis. Hum Genet 1996;97:625–31. 16. Kikuchi T, Toyota M, Itoh F, et al. Inactivation of p57KIP2 by regional promoter hypermethylation and histone deacetylation in human tumors. Oncogene 2002;21:2741–9. 17. Beretta C, Chiarelli A, Testoni B, Mantovani R, Guerrini L. Regulation of the cyclin-dependent kinase inhibitor p57Kip2 expression by p63. Cell Cycle 2005;4: 1625–31. 18. Georgia S, Soliz R, Li M, Zhang P, Bhushan A. p57 and Hes1 coordinate cell cycle exit with self-renewal of pancreatic progenitors. Dev Biol 2006;298:22–31. 19. Jia J, Lin M, Zhang L, York JP, Zhang P. The Notch signaling pathway controls the size of the ocular lens by directly suppressing p57Kip2 expression. Mol Cell Biol 2007;27:7236–47. 20. Alheim K, Corness J, Samuelsson MK, et al. Identification of a functional glucocorticoid response element in the promoter of the cyclin-dependent kinase inhibitor p57Kip2. J Mol Endocrinol 2003;30:359–68. 21. Dauphinot L, De Oliveira C, Melot T, et al. Analysis of the expression of cell cycle regulators in Ewing cell lines: EWS-FLI-1 modulates p57KIP2and c-Myc expression. Oncogene 2001;20:3258–65. 22. Adkins JN, Lumb KJ. Intrinsic structural disorder and sequence features of the cell cycle inhibitor p57Kip2. Proteins 2002;46:1–7. 23. Kriwacki RW, Hengst L, Tennant L, Reed SI, Wright PE. Structural studies of p21Waf1/Cip1/Sdi1 in the free and Cdk2-bound state: conformational disorder mediates binding diversity. Proc Natl Acad Sci U S A 1996;93:11504–9. 28. Reynaud EG, Guillier M, Leibovitch MP, Leibovitch SA. Dimerization of the amino terminal domain of p57Kip2 inhibits cyclin D1–4 kinase activity. Oncogene 2000;19:1147–52. 29. Hashimoto Y, Kohri K, Kaneko Y, et al. Critical role for the 310 helix region of p57(Kip2) in cyclin-dependent kinase 2 inhibition and growth suppression. J Biol Chem 1998;273:16544–50. 30. Blain SW, Montalvo E, Massague J. Differential interaction of the cyclindependent kinase (Cdk) inhibitor p27Kip1 with cyclin A-Cdk2 and cyclin D2– 4. J Biol Chem 1997;272:25863–72. 31. LaBaer J, Garrett MD, Stevenson LF, et al. New functional activities for the p21 family of CDK inhibitors. Genes Dev 1997;11:847–62. 32. Cheng M, Olivier P, Diehl JA, et al. The p21(Cip1) and p27(Kip1) CDK ‘inhibitors’ are essential activators of cyclin D-dependent kinases in murine fibroblasts. EMBO J 1999;18:1571–83. 33. Yokoo T, Toyoshima H, Miura M, et al. p57Kip2 regulates actin dynamics by binding and translocating LIM-kinase 1 to the nucleus. J Biol Chem 2003;278: 52919–23. 34. Watanabe H, Pan ZQ, Schreiber-Agus N, DePinho RA, Hurwitz J, Xiong Y. Suppression of cell transformation by the cyclin-dependent kinase inhibitor p57KIP2 requires binding to proliferating cell nuclear antigen. Proc Natl Acad Sci U S A 1998;95:1392–7. 35. Chang TS, Kim MJ, Ryoo K, et al. p57KIP2 modulates stress-activated signaling by inhibiting c-Jun NH2-terminal kinase/stress-activated protein Kinase. J Biol Chem 2003;278:48092–8. 36. Shim J, Lee H, Park J, Kim H, Choi EJ. A non-enzymatic p21 protein inhibitor of stress-activated protein kinases. Nature 1996;381:804–6. 37. Joaquin M, Watson RJ. The cell cycle-regulated B-Myb transcription factor overcomes cyclin-dependent kinase inhibitory activity of p57(KIP2) by interacting with its cyclin-binding domain. J Biol Chem 2003;278:44255–64. 38. Zhang P, Wong C, Liu D, Finegold M, Harper JW, Elledge SJ. p21(CIP1) and p57(KIP2) control muscle differentiation at the myogenin step. Genes Dev 1999; 13:213–24. 39. Nagahama H, Hatakeyama S, Nakayama K, Nagata M, Tomita K. Spatial and temporal expression patterns of the cyclin-dependent kinase (CDK) inhibitors p27Kip1 and p57Kip2 during mouse development. Anat Embryol (Berl) 2001; 203:77–87. 40. Awad MM, Sanders JA, Gruppuso PA. A potential role for p15(Ink4b) and p57(Kip2) in liver development. FEBS Lett 2000;483:160–4. 41. Westbury J, Watkins M, Ferguson-Smith AC, Smith J. Dynamic temporal and spatial regulation of the cdk inhibitor p57Kip2 during embryo morphogenesis. Mech Dev 2001;109:83–9. 42. Park CW, Chung JH. Age-dependent changes of p57Kip2 and p21Cip1/Waf1 expression in skeletal muscle and lung of mice. Biochim Biophys Acta 2001; 1520:163–8. 43. Ikoma T, Ito T, Okudela K, Hayashi H, Yazawa T, Kitamura H. Modulation of the expression of the Cip/Kip family of cyclin-dependent kinase inhibitors in foetal developing lungs of hamsters. Cell Prolif 2001;34:233–41. 44. Kim ST, Gye MC. Expression of p57Kip2 in mouse and human testis. Dev Growth Differ 2004;46:495–502. 45. Kim ST, Park NC, Yi LS, Gye MC. Expression of p57kip2 in germ cells and Leydig cells in human testis. Arch Androl 2006;52:463–9. 46. Smith AC, Choufani S, Ferreira JC, Weksberg R. Growth regulation, imprinted genes, and chromosome 11p15.5. Pediatr Res 2007;61:43–7R. 47. Ben-Porath I, Cedar H. Imprinting: focusing on the center. Curr Opin Genet Dev 2000;10:550–4. 48. Obata Y, Kono T. Maternal primary imprinting is established at a specific time for each gene throughout oocyte growth. J Biol Chem 2002;277:5285–9. 49. Reid LH, Davies C, Cooper PR, et al. A 1-Mb physical map and PAC contig of the imprinted domain in 11p15.5 that contains TAPA1 and the BWSCR1/WT2 region. Genomics 1997;43:366–75. 50. Caspary T, Cleary MA, Baker CC, Guan XJ, Tilghman SM. Multiple mechanisms regulate imprinting of the mouse distal chromosome 7 gene cluster. Mol Cell Biol 1998;18:3466–74. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review 51. Onyango P, Miller W, Lehoczky J, et al. Sequence and comparative analysis of the mouse 1-megabase region orthologous to the human 11p15 imprinted domain. Genome Res 2000;10:1697–710. 52. Hark AT, Schoenherr CJ, Katz DJ, Ingram RS, Levorse JM, Tilghman SM. CTCF mediates methylation-sensitive enhancer-blocking activity at the H19/Igf2 locus. Nature 2000;405:486–9. 53. Lee MP, DeBaun MR, Mitsuya K, et al. Loss of imprinting of a paternally expressed transcript, with antisense orientation to KVLQT1, occurs frequently in Beckwith-Wiedemann syndrome and is independent of insulin-like growth factor II imprinting. Proc Natl Acad Sci U S A 1999;96:5203–8. 54. Mitsuya K, Meguro M, Lee MP, et al. LIT1, an imprinted antisense RNA in the human KvLQT1 locus identified by screening for differentially expressed transcripts using monochromosomal hybrids. Hum Mol Genet 1999; 8:1209–17. 55. Smilinich NJ, Day CD, Fitzpatrick GV, et al. A maternally methylated CpG island in KvLQT1 is associated with an antisense paternal transcript and loss of imprinting in Beckwith-Wiedemann syndrome. Proc Natl Acad Sci U S A 1999; 96:8064–9. 56. Engemann S, Strödicke M, Paulsen M, et al. Sequence and functional comparison in the Beckwith-Wiedemann region: implications for a novel imprinting centre and extended imprinting. Hum Mol Genet 2000;9:2691–706. 57. Matsuoka S, Thompson JS, Edwards MC, et al. Imprinting of the gene encoding a human cyclin-dependent kinase inhibitor, p57KIP2, on chromosome 11p15. Proc Natl Acad Sci U S A 1996;93:3026–30. 58. Chung WY, Yuan L, Feng L, Hensle T, Tycko B. Chromosome 11p15.5 regional imprinting: comparative analysis of KIP2 and H19 in human tissues and Wilms' tumors. Hum Mol Genet 1996;5:1101–8. 59. Pateras IS, Apostolopoulou K, Koutsami M, et al. Downregulation of the KIP family members p27(KIP1) and p57(KIP2) by SKP2 and the role of methylation in p57(KIP2) inactivation in nonsmall cell lung cancer. Int J Cancer 2006; 119:2546–56. bidirectional silencing property of the Kcnq1 imprinting control region. Mol Cell Biol 2004;24:7855–62. 74. Mancini-Dinardo D, Steele SJ, Levorse JM, Ingram RS, Tilghman SM. Elongation of the Kcnq1ot1 transcript is required for genomic imprinting of neighboring genes. Genes Dev 2006;20:1268–82. 75. Murakami K, Oshimura M, Kugoh H. Suggestive evidence for chromosomal localization of non-coding RNA from imprinted LIT1. J Hum Genet 2007;52: 926–33. 76. Penny GD, Kay GF, Sheardown SA, Rastan S, Brockdorff N. Requirement for Xist in X chromosome inactivation. Nature 1996;379:131–7. 77. Sleutels F, Zwart R, Barlow DP. The non-coding Air RNA is required for silencing autosomal imprinted genes. Nature 2002;415:810–3. 78. Georgiades P, Watkins M, Burton GJ, Ferguson-Smith AC. Roles for genomic imprinting and the zygotic genome in placental development. Proc Natl Acad Sci U S A 2001;98:4522–7. 79. Ager EI, Pask AJ, Gehring HM, Shaw G, Renfree MB. Evolution of the CDKN1C-KCNQ1 imprinted domain. BMC Evol Biol 2008;8:163. 80. Fornari F, Gramantieri L, Ferracin M, et al. MiR-221 controls CDKN1C/p57 and CDKN1B/p27 expression in human hepatocellular carcinoma. Oncogene 2008;27:5651–61. 81. Kim YK, Yu J, Han TS, et al. Functional links between clustered microRNAs: suppression of cell-cycle inhibitors by microRNA clusters in gastric cancer. Nucleic Acids Res 2009;37:1672–81. 82. Medina R, Zaidi SK, Liu CG, et al. MicroRNAs 221 and 222 bypass quiescence and compromise cell survival. Cancer Res 2008;68:2773–80. 83. Qian K, Hu L, Chen H, et al. Has-miR-222 is involved in differentiation of endometrial stromal cells in vitro. Endocrinology 2009;150:4734–43. 84. Sengupta S, Nie J, Wagner RJ, Yang C, Stewart R, Thomson JA. MicroRNA 92b controls the G1/S checkpoint gene p57 in human embryonic stem cells. Stem Cells 2009;27:1524–8. 60. El Kharroubi A, Piras G, Stewart CL. DNA demethylation reactivates a subset of imprinted genes in uniparental mouse embryonic fibroblasts. J Biol Chem 2001;276:8674–80. 85. Chen H, Qian K, Tang ZP, et al. Bioinformatics and microarray analysis of microRNA expression profiles of murine embryonic stem cells, neural stem cells induced from ESCs and isolated from E8.5 mouse neural tube. Neurol Res, Epub 2009 Aug 5. 61. Yatsuki H, Joh K, Higashimoto K, et al. Domain regulation of imprinting cluster in Kip2/Lit1 subdomain on mouse chromosome 7F4/F5: large-scale DNA methylation analysis reveals that DMR-Lit1 is a putative imprinting control region. Genome Res 2002;12:1860–70. 86. Algar EM, Muscat A, Dagar V, et al. Imprinted CDKN1C is a tumor suppressor in rhabdoid tumor and activated by restoration of SMARCB1 and histone deacetylase inhibitors. PLoS One 2009;4:e4482. 62. Higashimoto K, Urano T, Sugiura K, et al. Loss of CpG methylation is strongly correlated with loss of histone H3 lysine 9 methylation at DMR-LIT1 in patients with Beckwith-Wiedemann syndrome. Am J Hum Genet 2003;73:948–56. 63. Lewis A, Mitsuya K, Umlauf D, et al. Imprinting on distal chromosome 7 in the placenta involves repressive histone methylation independent of DNA methylation. Nat Genet 2004;36:1291–5. 64. Umlauf D, Goto Y, Cao R, et al. Imprinting along the Kcnq1 domain on mouse chromosome 7 involves repressive histone methylation and recruitment of Polycomb group complexes. Nat Genet 2004;36:1296–300. 65. Horike S, Mitsuya K, Meguro M, et al. Targeted disruption of the human LIT1 locus defines a putative imprinting control element playing an essential role in Beckwith-Wiedemann syndrome. Hum Mol Genet 2000;9:2075–83. 66. Cleary MA, van Raamsdonk CD, Levorse J, Zheng B, Bradley A, Tilghman SM. Disruption of an imprinted gene cluster by a targeted chromosomal translocation in mice. Nat Genet 2001;29:78–82. 67. Fitzpatrick GV, Soloway PD, Higgins MJ. Regional loss of imprinting and growth deficiency in mice with a targeted deletion of KvDMR1. Nat Genet 2002; 32:426–31. 68. Kanduri C, Fitzpatrick G, Mukhopadhyay R, et al. A differentially methylated imprinting control region within the Kcnq1 locus harbors a methylation-sensitive chromatin insulator. J Biol Chem 2002;277:18106–10. 69. Du M, Beatty LG, Zhou W, et al. Insulator and silencer sequences in the imprinted region of human chromosome 11p15.5. Hum Mol Genet 2003;12: 1927–39. 70. Niemitz EL, DeBaun MR, Fallon J, et al. Microdeletion of LIT1 in familial Beckwith-Wiedemann syndrome. Am J Hum Genet 2004;75:844–9. 71. John RM, Hodges M, Little P, Barton SC, Surani MA. A human p57(KIP2) transgene is not activated by passage through the maternal mouse germline. Hum Mol Genet 1999;8:2211–9. 72. John RM, Ainscough JF, Barton SC, Surani MA. Distant cis-elements regulate imprinted expression of the mouse p57(Kip2) (Cdkn1c) gene: implications for the human disorder, Beckwith-Wiedemann syndrome. Hum Mol Genet 2001;10:1601–9. 73. Thakur N, Tiwari VK, Thomassin H, et al. An antisense RNA regulates the 87. Topark-Ngarm A, Golonzhka O, Peterson VJ, et al. CTIP2 associates with the NuRD complex on the promoter of p57KIP2, a newly identified CTIP2 target gene. J Biol Chem 2006;281:32272–83. 88. Yang X, Karaturi RK, Sun F, et al. CDKN1C (p57KIP2) is adirect target of EZH2 and suppressed by multiple epigenetic mechanisms in breast cancer cells. PLoS One 2009;4:e5011. 89. Cucciolla V, Borriello A, Criscuolo M, et al. Histone deacetylase inhibitors upregulate p57Kip2 level by enhancing its expression through Sp1 transcription factor. Carcinogenesis 2008;29:560–7. 90. Blint E, Phillips AC, Kozlov S, Stewart CL, Vousden KH. Induction of p57 (KIP2) expression by p73β. Proc Natl Acad Sci U S A 2002;99:3529–34. 91. el-Deiry WS, Tokino T, Velculescu VE, et al. WAF1, a potential mediator of p53 tumor suppression. Cell 1993;75:817–25. 92. Ma Y, Cress WD. Transcriptional upregulation of p57 (Kip2) by the cyclindependent kinase inhibitor BMS-387032 is E2F dependent and serves as a negative feedback loop limiting cytotoxicity. Oncogene 2007;26:3532–40. 93. Scandura JM, Boccuni P, Massague J, Nimer SD. Transforming growth factor β-induced cell cycle arrest of human hematopoietic cells requires p57KIP2 upregulation. Proc Natl Acad Sci U S A 2004;101:15231–6. 94. Chen Z, Li DQ, Tong L, Stewart P, Chu C, Pflugfelder SC. Targeted inhibition of p57 and p15 blocks transforming growth factor β-inhibited proliferation of primary cultured human limbal epithelial cells. Mol Vis 2006;12:983–94. 95. Lloyd RV, Erickson LA, Jin L, et al. p27kip1: a multifunctional cyclin-dependent kinase inhibitor with prognostic significance in human cancers. Am J Pathol 1999;154:313–23. 96. Roninson IB. Oncogenic functions of tumour suppressor p21(Waf1/Cip1/ Sdi1): association with cell senescence and tumour-promoting activities of stromal fibroblasts. Cancer Lett 2002;179:1–14. 97. Grandjean V, Smith J, Schofield PN, Ferguson-Smith AC. Increased IGF-II protein affects p57kip2 expression in vivo and in vitro: implications for BeckwithWiedemann syndrome. Proc Natl Acad Sci U S A 2000;97:5279–84. 98. Riccio O, van Gijn ME, Bezdek AC, et al. Loss of intestinal crypt progenitor cells owing to inactivation of both Notch1 and Notch2 is accompanied by derepression of CDK inhibitors p27Kip1 and p57Kip2. EMBO Rep 2008;9:377–83. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1915 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1916 Pateras et al. 99. Rothschild G, Zhao X, Iavarone A, Lasorella A. E Proteins and Id2 converge on p57Kip2 to regulate cell cycle in neural cells. Mol Cell Biol 2006;26:4351–61. chromosomal instability in non-small cell lung carcinomas. Mol Med 2001;7: 418–29. 100. Roeb W, Boyer A, Cavenee WK, Arden KC. PAX3–1 controls expression of the p57Kip2 cell-cycle regulator through degradation of EGR1. Proc Natl Acad Sci U S A 2007;104:18085–90. 126. Tsugu A, Sakai K, Dirks PB, et al. Expression of p57(KIP2) potently blocks the growth of human astrocytomas and induces cell senescence. Am J Pathol 2000;157:919–32. 101. Arima T, Kamikihara T, Hayashida T, et al. ZAC, LIT1 (KCNQ1OT1) and p57KIP2 (CDKN1C) are in an imprinted gene network that may play a role in Beckwith-Wiedemann syndrome. Nucleic Acids Res 2005;33:2650–60. 127. Schwarze SR, Shi Y, Fu VX, Watson PA, Jarrard DF. Role of cyclin-dependent kinase inhibitors in the growth arrest at senescence in human prostate epithelial and uroepithelial cells. Oncogene 2001;20:8184–92. 102. Varrault A, Gueydan C, Delalbre A, et al. Zac1 regulates an imprinted gene network critically involved in the control of embryonic growth. Dev Cell 2006;11:711–22. 128. Yan Y, Frisen J, Lee MH, Massague J, Barbacid M. Ablation of the CDK inhibitor p57Kip2 results in increased apoptosis and delayed differentiation during mouse development. Genes Dev 1997;11:973–83. 103. Samuelsson MK, Pazirandeh A, Davani B, Okret S. p57Kip2, a glucocorticoidinduced inhibitor of cell cycle progression in HeLa cells. Mol Endocrinol 1999;13: 1811–22. 104. Pedram A, Razandi M, Hu RM, Levin ER. Astrocyte progression from G1 to S phase of the cell cycle depends upon multiple protein interaction. J Biol Chem 1998;273:13966–72. 105. Lu L, Qiu J, Liu S, Luo W. Vitamin D3 analogue EB1089 inhibits the proliferation of human laryngeal squamous carcinoma cells via p57. Mol Cancer Ther 2008;7:1268–74. 106. Kido K, Doerks A, Lochelt M, Flugel RM. Identification and functional characterization of an intragenic DNA binding site for the spumaretroviral trans-activator in the human p57Kip2 gene. J Biol Chem 2002;277:12032–9. 107. Nakayama KI, Nakayama K. Ubiquitin ligases: cell-cycle control and cancer. Nat Rev Cancer 2006;6:369–81. 108. Kamura T, Hara T, Kotoshiba S, et al. Degradation of p57Kip2 mediated by SCFSkp2-dependent ubiquitylation. Proc Natl Acad Sci U S A 2003;100:10231–6. 109. Urano T, Yashiroda H, Muraoka M, et al. p57(Kip2) is degraded through the proteasome in osteoblasts stimulated to proliferation by transforming growth factor β1. J Biol Chem 1999;274:12197–200. 110. Nishimori S, Tanaka Y, Chiba T, et al. Smad-mediated transcription is required for transforming growth factor-β 1-induced p57(Kip2) proteolysis in osteoblastic cells. J Biol Chem 2001;276:10700–5. 111. Kim M, Nakamoto T, Nishimori S, Tanaka K, Chiba T. A new ubiquitin ligase involved in p57KIP2 proteolysis regulates osteoblast cell differentiation. EMBO Rep 2008;9:878–84. 112. Sinuani I, Weissgarten J, Beberashvili I, et al. The cyclin kinase inhibitor p57kip2 regulates TGF-{β}-induced compensatory tubular hypertrophy: effect of the immunomodulator AS101. Nephrol Dial Transplant 2009;24:2328–38. 113. Chu IM, Hengst L, Slingerland JM. The Cdk inhibitor p27 in human cancer: prognostic potential and relevance to anticancer therapy. Nat Rev Cancer 2008;8: 253–67. 129. Zhang P, Liegeois NJ, Wong C, et al. Altered cell differentiation and proliferation in mice lacking p57KIP2 indicates a role in Beckwith-Wiedemann syndrome. Nature 1997;387:151–8. 130. Takahashi K, Nakayama K, Nakayama K. Mice lacking a CDK inhibitor, p57Kip2, exhibit skeletal abnormalities and growth retardation. J Biochem 2000; 127:73–83. 131. Andrews SC, Wood MD, Tunster SJ, Barton SC, Surani MA, John RM. Cdkn1c (p57Kip2) is the major regulator of embryonic growth within its imprinted domain on mouse distal chromosome 7. BMC Dev Biol 2007;7:53. 132. Karaplis AC, Luz A, Glowacki J, et al. Lethal skeletal dysplasia from targeted disruption of the parathyroid hormone-related peptide gene. Genes Dev 1994;8:277–89. 133. MacLean HE, Guo J, Knight MC, Zhang P, Cobrinik D, Kronenberg HM. The cyclin-dependent kinase inhibitor p57(Kip2) mediates proliferative actions of PTHrP in chondrocytes. J Clin Invest 2004;113:1334–43. 134. Takahashi K, Kobayashi T, Kanayama N. p57(Kip2) regulates the proper development of labyrinthine and spongiotrophoblasts. Mol Hum Reprod 2000; 6:1019–25. 135. Brugarolas J, Chandrasekaran C, Gordon JI, Beach D, Jacks T, Hannon GJ. Radiation-induced cell cycle arrest compromised by p21 deficiency. Nature 1995; 377:552–7. 136. Deng C, Zhang P, Harper JW, Elledge SJ, Leder P. Mice lacking p21CIP1/ WAF1 undergo normal development, but are defective in G1 checkpoint control. Cell 1995;82:675–84. 137. Fero ML, Rivkin M, Tasch M, et al. A syndrome of multiorgan hyperplasia with features of gigantism, tumorigenesis, and female sterility in p27(Kip1)deficient mice. Cell 1996;85:733–44. 138. Kiyokawa H, Kineman RD, Manova-Todorova KO, et al. Enhanced growth of mice lacking the cyclin-dependent kinase inhibitor function of p27(Kip1). Cell 1996;85:721–32. 114. Ullah Z, Lee CY, Depamphilis ML. Cip/Kip cyclin-dependent protein kinase inhibitors and the road to polyploidy. Cell Div 2009;4:10. 139. Nakayama K, Ishida N, Shirane M, et al. Mice lacking p27(Kip1) display increased body size, multiple organ hyperplasia, retinal dysplasia, and pituitary tumors. Cell 1996;85:707–20. 115. Hattori N, Davies TC, Anson-Cartwright L, Cross JC. Periodic expression of the cyclin-dependent kinase inhibitor p57(Kip2) in trophoblast giant cells defines a G2-like gap phase of the endocycle. Mol Biol Cell 2000;11:1037–45. 140. Zhang P, Wong C, DePinho RA, Harper JW, Elledge SJ. Cooperation between the Cdk inhibitors p27(KIP1) and p57(KIP2) in the control of tissue growth and development. Genes Dev 1998;12:3162–7. 116. Ullah Z, Kohn MJ, Yagi R, Vassilev LT, DePamphilis ML. Differentiation of trophoblast stem cells into giant cells is triggered by p57/Kip2 inhibition of CDK1 activity. Genes Dev 2008;22:3024–36. 141. Susaki E, Nakayama K, Yamasaki L, Nakayama KI. Common and specific roles of the related CDK inhibitors p27 and p57 revealed by a knock-in mouse model. Proc Natl Acad Sci U S A 2009;106:5192–7. 117. Merlo P, Fulco M, Costanzo A, et al. A role of p73 in mitotic exit. J Biol Chem 2005;280:30354–60. 142. Bartkova J, Lukas J, Strauss M, Bartek J. Cyclin D3: requirement for G1/S transition and high abundance in quiescent tissues suggest a dual role in proliferation and differentiation. Oncogene 1998;17:1027–37. 118. Burridge K, Wennerberg K. Rho and Rac take center stage. Cell 2004;116: 167–79. 119. Besson A, Dowdy SF, Roberts JM. CDK inhibitors: cell cycle regulators and beyond. Dev Cell 2008;14:159–69. 143. Gao CY, Rampalli AM, Cai HC, He HY, Zelenka PS. Changes in cyclin dependent kinase expression and activity accompanying lens fiber cell differentiation. Exp Eye Res 1999;69:695–703. 120. Samuelsson MK, Pazirandeh A, Okret S. A pro-apoptotic effect of the CDK inhibitor p57(Kip2) on staurosporine-induced apoptosis in HeLa cells. Biochem Biophys Res Commun 2002;296:702–9. 144. Gomez Lahoz E, Liegeois NJ, Zhang P, et al. Cyclin D- and E-dependent kinases and the p57(KIP2) inhibitor: cooperative interactions in vivo. Mol Cell Biol 1999;19:353–63. 121. Vlachos P, Nyman U, Hajji N, Joseph B. The cell cycle inhibitor p57(Kip2) promotes cell death via the mitochondrial apoptotic pathway. Cell Death Differ 2007;14:1497–507. 145. Dyer MA, Cepko CL. p27Kip1 and p57Kip2 regulate proliferation in distinct retinal progenitor cell populations. J Neurosci 2001;21:4259–71. 122. Gonzalez S, Perez-Perez MM, Hernando E, Serrano M, Cordon-Cardo C. p73β-Mediated apoptosis requires p57kip2 induction and IEX-1 inhibition. Cancer Res 2005;65:2186–92. 123. Jiang Y, Lo W, Akhmametyeva EM, Chang LS. Over-expression of p73β results in apoptotic death of post-mitotic hNT neurons. J Neurol Sci 2006;240:1–6. 124. Gartel AL, Tyner AL. The role of the cyclin-dependent kinase inhibitor p21 in apoptosis. Mol Cancer Ther 2002;1:639–49. 125. Tsoli E, Gorgoulis VG, Zacharatos P, et al. Low levels of p27 in association with deregulated p53-pRb protein status enhance tumor proliferation and 146. Murata K, Hattori M, Hirai N, et al. Hes1 directly controls cell proliferation through the transcriptional repression of p27Kip1. Mol Cell Biol 2005;25: 4262–71. 147. Dyer MA, Cepko CL. p57(Kip2) regulates progenitor cell proliferation and amacrine interneuron development in the mouse retina. Development 2000;127: 3593–605. 148. Shkumatava A, Neumann CJ. Shh directs cell-cycle exit by activating p57Kip2 in the zebrafish retina. EMBO Rep 2005;6:563–9. 149. Cunningham JJ, Roussel MF. Cyclin-dependent kinase inhibitors in the development of the central nervous system. Cell Growth Differ 2001;12: 387–96. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review 150. Itoh Y, Masuyama N, Nakayama K, Nakayama KI, Gotoh Y. The cyclindependent kinase inhibitors p57 and p27 regulate neuronal migration in the developing mouse neocortex. J Biol Chem 2007;282:390–6. 174. Cooper WN, Luharia A, Evans GA, et al. Molecular subtypes and phenotypic expression of Beckwith-Wiedemann syndrome. Eur J Hum Genet 2005;13: 1025–32. 151. Ye W, Mairet-Coello G, Pasoreck E, Dicicco-Bloom E. Patterns of p57Kip2 expression in embryonic rat brain suggest roles in progenitor cell cycle exit and neuronal differentiation. Dev Neurobiol 2009;69:1–21. 175. Diaz-Meyer N, Day CD, Khatod K, et al. Silencing of CDKN1C (p57KIP2) is associated with hypomethylation at KvDMR1 in Beckwith-Wiedemann syndrome. J Med Genet 2003;40:797–801. 152. Dugas JC, Ibrahim A, Barres BA. A crucial role for p57(Kip2) in the intracellular timer that controls oligodendrocyte differentiation. J Neurosci 2007;27: 6185–96. 153. Kremer D, Heinen A, Jadasz J, et al. p57kip2 is dynamically regulated in experimental autoimmune encephalomyelitis and interferes with oligodendroglial maturation. Proc Natl Acad Sci U S A 2009;106:9087–92. 154. Joseph B, Wallen-Mackenzie A, Benoit G, et al. p57(Kip2) cooperates with Nurr1 in developing dopamine cells. Proc Natl Acad Sci U S A 2003; 100:15619–24. 176. Cerrato F, Vernucci M, Pedone PV, et al. The 5′ end of the KCNQ1OT1 gene is hypomethylated in the Beckwith-Wiedemann syndrome. Hum Genet 2002;111:105–7. 155. Heinen A, Kremer D, Gottle P, et al. The cyclin-dependent kinase inhibitor p57kip2 is a negative regulator of Schwann cell differentiation and in vitro myelination. Proc Natl Acad Sci U S A 2008;105:8748–53. 156. Reynaud EG, Pelpel K, Guillier M, Leibovitch MP, Leibovitch SA. p57 (Kip2) stabilizes the MyoD protein by inhibiting cyclin E-Cdk2 kinase activity in growing myoblasts. Mol Cell Biol 1999;19:7621–9. 157. Reynaud EG, Leibovitch MP, Tintignac LA, Pelpel K, Guillier M, Leibovitch SA. Stabilization of MyoD by direct binding to p57(Kip2). J Biol Chem 2000;275:18767–76. 158. Kitzmann M, Fernandez A. Crosstalk between cell cycle regulators and the myogenic factor MyoD in skeletal myoblasts. Cell Mol Life Sci 2001;58:571–9. 159. Vaccarello G, Figliola R, Cramerotti S, Novelli F, Maione R. p57Kip2 is induced by MyoD through a p73-dependent pathway. J Mol Biol 2006;356: 578–88. 177. Weksberg R, Shuman C, Smith AC. Beckwith-Wiedemann syndrome. Am J Med Genet C Semin Med Genet 2005;137C:12–23. 178. Hatada I, Ohashi H, Fukushima Y, et al. An imprinted gene p57KIP2 is mutated in Beckwith-Wiedemann syndrome. Nat Genet 1996;14:171–3. 179. Hatada I, Nabetani A, Morisaki H, et al. New p57KIP2 mutations in Beckwith-Wiedemann syndrome. Hum Genet 1997;100:681–3. 180. Lee MP, DeBaun M, Randhawa G, Reichard BA, Elledge SJ, Feinberg AP. Low frequency of p57KIP2 mutation in Beckwith-Wiedemann syndrome. Am J Hum Genet 1997;61:304–9. 181. O'Keefe D, Dao D, Zhao L, et al. Coding mutations in p57KIP2 are present in some cases of Beckwith-Wiedemann syndrome but are rare or absent in Wilms tumors. Am J Hum Genet 1997;61:295–303. 182. Bhuiyan ZA, Yatsuki H, Sasaguri T, et al. Functional analysis of the p57KIP2 gene mutation in Beckwith-Wiedemann syndrome. Hum Genet 1999; 104:205–10. 183. Kotzot D. Complex and segmental uniparental disomy (UPD): review and lessons from rare chromosomal complements. J Med Genet 2001;38:497–507. 184. Algar EM, Deeble GJ, Smith PJ. CDKN1C expression in BeckwithWiedemann syndrome patients with allele imbalance. J Med Genet 1999;36:524–31. 160. Hiromura K, Haseley LA, Zhang P, et al. Podocyte expression of the CDK-inhibitor p57 during development and disease. Kidney Int 2001;60: 2235–46. 185. Grati FR, Turolla L, D'Ajello P, et al. Chromosome 11 segmental paternal isodisomy in amniocytes from two fetuses with omphalocoele: new highlights on phenotype-genotype correlations in Beckwith-Wiedemann syndrome. J Med Genet 2007;44:257–63. 161. Chilosi M, Piazzola E, Lestani M, et al. Differential expression of p57kip2, a maternally imprinted cdk inhibitor, in normal human placenta and gestational trophoblastic disease. Lab Invest 1998;78:269–76. 186. Caspary T, Cleary MA, Perlman EJ, Zhang P, Elledge SJ, Tilghman SM. Oppositely imprinted genes p57(Kip2) and igf2 interact in a mouse model for Beckwith-Wiedemann syndrome. Genes Dev 1999;13:3115–24. 162. Martinez LA, Chen Y, Fischer SM, Conti CJ. Coordinated changes in cell cycle machinery occur during keratinocyte terminal differentiation. Oncogene 1999;18:397–406. 187. Kanayama N, Takahashi K, Matsuura T, et al. Deficiency in p57Kip2 expression induces preeclampsia-like symptoms in mice. Mol Hum Reprod 2002;8: 1129–35. 163. Gosselet FP, Magnaldo T, Culerrier RM, Sarasin A, Ehrhart JC. BMP2 and BMP6 control p57(Kip2) expression and cell growth arrest/terminal differentiation in normal primary human epidermal keratinocytes. Cell Signal 2007; 19:731–9. 188. Knox KS, Baker JC. Genome-wide expression profiling of placentas in the p57Kip2 model of pre-eclampsia. Mol Hum Reprod 2007;13:251–63. 164. Bilodeau S, Roussel-Gervais A, Drouin J. Distinct developmental roles of cell cycle inhibitors p57Kip2 and p27Kip1 distinguish pituitary progenitor cell cycle exit from cell cycle reentry of differentiated cells. Mol Cell Biol 2009; 29:1895–908. 165. Li G, Domenico J, Lucas JJ, Gelfand EW. Identification of multiple cell cycle regulatory functions of p57Kip2 in human T lymphocytes. J Immunol 2004;173:2383–91. 166. Umemoto T, Yamato M, Nishida K, Yang J, Tano Y, Okano T. p57Kip2 is expressed in quiescent mouse bone marrow side population cells. Biochem Biophys Res Commun 2005;337:14–21. 167. Stewart MC, Kadlcek RM, Robbins PD, MacLeod JN, Ballock RT. Expression and activity of the CDK inhibitor p57Kip2 in chondrocytes undergoing hypertrophic differentiation. J Bone Miner Res 2004;19:123–32. 168. Kobayashi H, Kambe F, Imai T, et al. Differential expression of cyclindependent kinase inhibitors, p27Kip1 and p57Kip2, by corticotropin in rat adrenal cortex. J Endocrinol 2006;189:671–9. 169. Swanger WJ, Roberts JM. p57KIP2 targeted disruption and BeckwithWiedemann syndrome: is the inhibitor just a contributor? Bioessays 1997;19: 839–42. 170. Wiedemann HR. Tumors and hemihypertrophy associated with Wiedemann-Beckwith syndrome. Eur J Pediatr 1983;141:129–34. 171. Catchpoole D, Lam WW, Valler D, et al. Epigenetic modification and uniparental inheritance of H19 in Beckwith-Wiedemann syndrome. J Med Genet 1997;34:353–9. 172. Lam WW, Hatada I, Ohishi S, et al. Analysis of germline CDKN1C (p57KIP2) mutations in familial and sporadic Beckwith-Wiedemann syndrome (BWS) provides a novel genotype-phenotype correlation. J Med Genet 1999; 36:518–23. 173. Engel JR, Smallwood A, Harper A, et al. Epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome. J Med Genet 2000;37:921–6. 189. Falcao S, Solomon C, Monat C, Berube J, Gutkowska J, Lavoie JL. Impact of diet and stress on the development of preeclampsia-like symptoms in p57kip2 mice. Am J Physiol Heart Circ Physiol 2009;296:H119–26. 190. Romanelli V, Belinchon A, Campos-Barros A, et al. CDKN1C mutations in HELLP/preeclamptic mothers of Beckwith-Wiedemann Syndrome (BWS) patients. Placenta 2009;30:551–4. 191. Castrillon DH, Sun D, Weremowicz S, Fisher RA, Crum CP, Genest DR. Discrimination of complete hydatidiform mole from its mimics by immunohistochemistry of the paternally imprinted gene product p57KIP2. Am J Surg Pathol 2001;25:1225–30. 192. Jun SY, Ro JY, Kim KR. p57kip2 is useful in the classification and differential diagnosis of complete and partial hydatidiform moles. Histopathology 2003;43:17–25. 193. Kihara M, Matsui H, Seki K, Nagai Y, Wake N, Sekiya S. Genetic origin and imprinting in hydatidiform moles. Comparison between DNA polymorphism analysis and immunoreactivity of p57KIP2. J Reprod Med 2005;50:307–12. 194. Merchant SH, Amin MB, Viswanatha DS, Malhotra RK, Moehlenkamp C, Joste NE. p57KIP2 immunohistochemistry in early molar pregnancies: emphasis on its complementary role in the differential diagnosis of hydropic abortuses. Hum Pathol 2005;36:180–6. 195. Soma H, Osawa H, Oguro T, et al. P57kip2 immunohistochemical expression and ultrastructural findings of gestational trophoblastic disease and related disorders. Med Mol Morphol 2007;40:95–102. 196. Hoffner L, Dunn J, Esposito N, Macpherson T, Surti U. P57KIP2 immunostaining and molecular cytogenetics: combined approach aids in diagnosis of morphologically challenging cases with molar phenotype and in detecting androgenetic cell lines in mosaic/chimeric conceptions. Hum Pathol 2008;39:63–72. 197. Wells M. The pathology of gestational trophoblastic disease: recent advances. Pathology 2007;39:88–96. 198. Burton PB, Yacoub MH, Barton PJ. Cyclin-dependent kinase inhibitor expression in human heart failure. A comparison with fetal development. Eur Heart J 1999;20:604–11. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1917 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 1918 Pateras et al. 199. Rodriguez I, Coto E, Reguero JR, et al. Role of the CDKN1A/p21, CDKN1C/p57, and CDKN2A/p16 genes in the risk of atherosclerosis and myocardial infarction. Cell Cycle 2007;6:620–5. 224. Lai S, Goepfert H, Gillenwater AM, Luna MA, El-Naggar AK. Loss of imprinting and genetic alterations of the cyclin-dependent kinase inhibitor p57KIP2 gene in head and neck squamous cell carcinoma. Clin Cancer Res 2000;6:3172–6. 200. Haley SA, Zhao T, Zou L, Klysik JE, Padbury JF, Kochilas LK. Forced expression of the cell cycle inhibitor p57Kip2 in cardiomyocytes attenuates ischemia-reperfusion injury in the mouse heart. BMC Physiol 2008;8:4. 201. Wang S, Kim JH, Moon KC, Hong HK, Lee HS. Cell-cycle mechanisms involved in podocyte proliferation in cellular lesion of focal segmental glomerulosclerosis. Am J Kidney Dis 2004;43:19–27. 202. Petermann A, Hiromura K, Pippin J, et al. Differential expression of D-type cyclins in podocytes in vitro and in vivo. Am J Pathol 2004;164:1417–24. 203. Felekkis KN, Koupepidou P, Kastanos E, et al. Mutant polycystin-2 induces proliferation in primary rat tubular epithelial cells in a STAT-1/p21-independent fashion accompanied instead by alterations in expression of p57KIP2 and Cdk2. BMC Nephrol 2008;9:10. 204. Ryan F, Devaney D, Joyce C, et al. Hyperinsulinism: molecular aetiology of focal disease. Arch Dis Child 1998;79:445–7. 205. Kassem SA, Ariel I, Thornton PS, et al. p57(KIP2) expression in normal islet cells and in hyperinsulinism of infancy. Diabetes 2001;50:2763–9. 229. Shin JY, Kim HS, Lee KS, et al. Mutation and expression of the p27KIP1 and p57KIP2 genes in human gastric cancer. Exp Mol Med 2000;32:79–83. 206. Jin RJ, Lho Y, Wang Y, et al. Downregulation of p57Kip2 induces prostate cancer in the mouse. Cancer Res 2008;68:3601–8. 230. Ito Y, Takeda T, Wakasa K, Tsujimoto M, Matsuura N. Expression of p57/ Kip2 protein in pancreatic adenocarcinoma. Pancreas 2001;23:246–50. 207. Martin-Caballero J, Flores JM, Garcia-Palencia P, Serrano M. Tumor susceptibility of p21(Waf1/Cip1)-deficient mice. Cancer Res 2001;61:6234–8. 231. Yue H, Na YL, Feng XL, Ma SR, Song FL, Yang B. Expression of p57kip2, Rb protein and PCNA and their relationships with clinicopathology in human pancreatic cancer. World J Gastroenterol 2003;9:377–80. 208. Nijjar T, Wigington D, Garbe JC, Waha A, Stampfer MR, Yaswen P. p57KIP2 expression and loss of heterozygosity during immortal conversion of cultured human mammary epithelial cells. Cancer Res 1999;59:5112–8. 209. Hernandez L, Kozlov S, Piras G, Stewart CL. Paternal and maternal genomes confer opposite effects on proliferation, cell-cycle length, senescence, and tumor formation. Proc Natl Acad Sci U S A 2003;100:13344–9. 210. Kuang SQ, Ling X, Sanchez-Gonzalez B, Yang H, Andreeff M, Garcia-Manero G. Differential tumor suppressor properties and transforming growth factor-β responsiveness of p57KIP2 in leukemia cells with aberrant p57KIP2 promoter DNA methylation. Oncogene 2007;26:1439–48. 211. Sakai K, Peraud A, Mainprize T, et al. Inducible expression of p57KIP2 inhibits glioma cell motility and invasion. J Neurooncol 2004;68:217–23. 212. Hatada I, Inazawa J, Abe T, et al. Genomic imprinting of human p57KIP2 and its reduced expression in Wilms' tumors. Hum Mol Genet 1996;5:783–8. 213. Orlow I, Iavarone A, Crider-Miller SJ, et al. Cyclin-dependent kinase inhibitor p57KIP2 in soft tissue sarcomas and Wilms'tumors. Cancer Res 1996;56: 1219–21. 214. Thompson JS, Reese KJ, DeBaun MR, Perlman EJ, Feinberg AP. Reduced expression of the cyclin-dependent kinase inhibitor gene p57KIP2 in Wilms' tumor. Cancer Res 1996;56:5723–7. 225. Fan GK, Chen J, Ping F, Geng Y. Immunohistochemical analysis of P57 (kip2), p53 and hsp60 expressions in premalignant and malignant oral tissues. Oral Oncol 2006;42:147–53. 226. Fan GK, Xu F, Yang B, Fujieda S. p57(kip2) expression is related to carcinogenesis and tumor progression in laryngeal tissues. Acta Otolaryngol 2006; 126:301–5. 227. Kobatake T, Yano M, Toyooka S, et al. Aberrant methylation of p57KIP2 gene in lung and breast cancers and malignant mesotheliomas. Oncol Rep 2004; 12:1087–92. 228. Kondo M, Matsuoka S, Uchida K, et al. Selective maternal-allele loss in human lung cancers of the maternally expressed p57KIP2 gene at 11p15.5. Oncogene 1996;12:1365–8. 232. Bonilla F, Orlow I, Cordon-Cardo C. Mutational study of p16CDKN2/ MTS1/INK4A and p57KIP2 genes in hepatocellular carcinoma. Int J Oncol 1998;12:583–8. 233. Schwienbacher C, Gramantieri L, Scelfo R, et al. Gain of imprinting at chromosome 11p15: A pathogenetic mechanism identified in human hepatocarcinomas. Proc Natl Acad Sci U S A 2000;97:5445–9. 234. Ito Y, Takeda T, Sakon M, Tsujimoto M, Monden M, Matsuura N. Expression of p57/Kip2 protein in hepatocellular carcinoma. Oncology 2001;61:221–5. 235. Nakai S, Masaki T, Shiratori Y, et al. Expression of p57(KIP2) in hepatocellular carcinoma: relationship between tumor differentiation and patient survival. Int J Oncol 2002;20:769–75. 236. Nan KJ, Guo H, Ruan ZP, Jing Z, Liu SX. Expression of p57(kip2) and its relationship with clinicopathology, PCNA and p53 in primary hepatocellular carcinoma. World J Gastroenterol 2005;11:1237–40. 237. Ito Y, Takeda T, Sasaki Y, et al. Expression of p57/Kip2 protein in extrahepatic bile duct carcinoma and intrahepatic cholangiocellular carcinoma. Liver 2002;22:145–9. 238. Oya M, Schulz WA. Decreased expression of p57(KIP2)mRNA in human bladder cancer. Br J Cancer 2000;83:626–31. 215. Overall ML, Spencer J, Bakker M, Dziadek M, Smith PJ. p57K1P2 is expressed in Wilms' tumor with LOH of 11p15.5. Genes Chromosomes Cancer 1996;17:56–9. 239. Bozdogan O, Atasoy P, Batislam E, Basar MM, Basar H. Significance of p57(Kip2) downregulation in oncogenesis of bladder carcinoma: an immunohistochemical study. Tumori 2008;94:556–62. 216. Taniguchi T, Okamoto K, Reeve AE. Human p57(KIP2) defines a new imprinted domain on chromosome 11p but is not a tumour suppressor gene in Wilms tumour. Oncogene 1997;14:1201–6. 240. Larson PS, Schlechter BL, King CL, et al. CDKN1C/p57kip2 is a candidate tumor suppressor gene in human breast cancer. BMC Cancer 2008;8:68. 217. Satoh Y, Nakadate H, Nakagawachi T, et al. Genetic and epigenetic alterations on the short arm of chromosome 11 are involved in a majority of sporadic Wilms' tumours. Br J Cancer 2006;95:541–7. 218. Hartmann W, Waha A, Koch A, et al. p57(KIP2) is not mutated in hepatoblastoma but shows increased transcriptional activity in a comparative analysis of the three imprinted genes p57(KIP2), IGF2, and H19. Am J Pathol 2000;157: 1393–403. 219. Shen L, Toyota M, Kondo Y, et al. Aberrant DNA methylation of p57KIP2 identifies a cell-cycle regulatory pathway with prognostic impact in adult acute lymphocytic leukemia. Blood 2003;101:4131–6. 220. Bueso-Ramos C, Xu Y, McDonnell TJ, et al. Protein expression of a triad of frequently methylated genes, p73, p57Kip2, and p15, has prognostic value in adult acute lymphocytic leukemia independently of its methylation status. J Clin Oncol 2005;23:3932–9. 221. Canalli AA, Yang H, Jeha S, et al. Aberrant DNA methylation of a cell cycle regulatory pathway composed of P73, P15 and P57KIP2 is a rare event in children with acute lymphocytic leukemia. Leuk Res 2005;29:881–5. 222. Gutierrez MI, Siraj AK, Ibrahim MM, Hussain A, Bhatia K. Childhood and adult ALL: differences in epigenetic lesions associated with cell cycle genes. Am J Hematol 2005;80:158–60. 223. Li Y, Nagai H, Ohno T, et al. Aberrant DNA methylation of p57(KIP2) gene in the promoter region in lymphoid malignancies of B-cell phenotype. Blood 2002;100:2572–7. 241. Rosenberg E, Demopoulos RI, Zeleniuch-Jacquotte A, et al. Expression of cell cycle regulators p57(KIP2), cyclin D1, and cyclin E in epithelial ovarian tumors and survival. Hum Pathol 2001;32:808–13. 242. Sui L, Dong Y, Ohno M, Watanabe Y, Sugimoto K, Tokuda M. Expression of p57kip2 and its clinical relevance in epithelial ovarian tumors. Anticancer Res 2002;22:3191–6. 243. Liu J, Kahri AI, Heikkila P, Voutilainen R. Ribonucleic acid expression of the clustered imprinted genes, p57KIP2, insulin-like growth factor II, and H19, in adrenal tumors and cultured adrenal cells. J Clin Endocrinol Metab 1997;82: 1766–71. 244. Bourcigaux N, Gaston V, Logie A, Bertagna X, Le Bouc Y, Gicquel C. High expression of cyclin E and G1 CDK and loss of function of p57KIP2 are involved in proliferation of malignant sporadic adrenocortical tumors. J Clin Endocrinol Metab 2000;85:322–30. 245. Ito Y, Yoshida H, Nakano K, et al. Expression of p57/Kip2 protein in normal and neoplastic thyroid tissues. Int J Mol Med 2002;9:373–6. 246. Matsumoto M, Furihata M, Ohtsuki Y, Sasaguri S, Ogoshi S. Immunohistochemical characterization of p57KIP2 expression in human esophageal squamous cell carcinoma. Anticancer Res 2000;20:1947–52. 247. Sato N, Matsubayashi H, Abe T, Fukushima N, Goggins M. Epigenetic downregulation of CDKN1C/p57KIP2 in pancreatic ductal neoplasms identified by gene expression profiling. Clin Cancer Res 2005;11:4681–8. 248. Li JQ, Wu F, Usuki H, et al. Loss of p57KIP2 is associated with colorectal carcinogenesis. Int J Oncol 2003;23:1537–43. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 A p57KIP2 Review 249. Hoffmann MJ, Florl AR, Seifert HH, Schulz WA. Multiple mechanisms downregulate CDKN1C in human bladder cancer. Int J Cancer 2005;114:406–13. 257. Koutsami M, Velimezi G, Kotsinas A, et al. Is exclusive Skp2 targeting always in cancer therapy? Blood 2008;112:4777–9. 250. Bartkova J, Rezaei N, Liontos M, et al. Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints. Nature 2006;444:633–7. 258. Nakano S, Murakami K, Meguro M, et al. Expression profile of LIT1/ KCNQ1OT1 and epigenetic status at the KvDMR1 in colorectal cancers. Cancer Sci 2006;97:1147–54. 251. Gorgoulis VG, Vassiliou LV, Karakaidos P, et al. Activation of the DNA damage checkpoint and genomic instability in human precancerous lesions. Nature 2005;434:907–13. 259. Seizinger BR, Klinger HP, Junien C, et al. Report of the committee on chromosome and gene loss in human neoplasia. Cytogenet Cell Genet 1991; 58:1080–96. 252. Halazonetis TD, Gorgoulis VG, Bartek J. An oncogene-induced DNA damage model for cancer development. Science 2008;319:1352–5. 260. Soejima H, Nakagawachi T, Zhao W, et al. Silencing of imprinted CDKN1C gene expression is associated with loss of CpG and histone H3 lysine 9 methylation at DMR-LIT1 in esophageal cancer. Oncogene 2004;23:4380–8. 253. Liontos M, Niforou K, Velimezi G, et al. Modulation of the E2F1-driven cancer cell fate by the DNA damage response machinery and potential novel E2F1 targets in osteosarcomas. Am J Pathol 2009;175:376–91. 254. Gray SG, Ekstrom TJ. Effects of cell density and trichostatin A on the expression of HDAC1 and p57Kip2 in Hep 3B cells. Biochem Biophys Res Commun 1998;245:423–7. 255. Shin JY, Kim HS, Park J, Park JB, Lee JY. Mechanism for inactivation of the KIP family cyclin-dependent kinase inhibitor genes in gastric cancer cells. Cancer Res 2000;60:262–5. 256. Lemaire M, Chabot GG, Raynal NJ, et al. Importance of dose-schedule of 5-aza-2′-deoxycytidine for epigenetic therapy of cancer. BMC Cancer 2008;8:128. 261. Yoshioka K, Foletta V, Bernard O, Itoh K. A role for LIM kinase in cancer invasion. Proc Natl Acad Sci U S A 2003;100:7247–52. 262. Li Y, Millikan RC, Newman B, Conway K, Tse CK, Liu ET. P57 (KIP2) polymorphisms and breast cancer risk. Hum Genet 1999;104:83–8. 263. Vlachos P, Joseph B. The Cdk inhibitor p57(Kip2) controls LIM-kinase 1 activity and regulates actin cytoskeleton dymanics. Oncogene 2009 Sep 7. [Epub ahead of print]. 264. Mascarenhas MI, Parker A, Dzierzak E, Ottersbach K. Identification of novel regulators of hematopoietic stem cell development through refinement of stem cell localization and expression profiling. Blood 2009 Sep 30. [Epub ahead of print]. Mol Cancer Res 2009;7(12). December 2009 Downloaded from mcr.aacrjournals.org on June 15, 2017. © 2009 American Association for Cancer Research. 1919 Published OnlineFirst November 24, 2009; DOI: 10.1158/1541-7786.MCR-09-0317 p57KIP2: ''Kip''ing the Cell under Control Ioannis S. Pateras, Kalliopi Apostolopoulou, Katerina Niforou, et al. Mol Cancer Res 2009;7:1902-1919. Published OnlineFirst November 24, 2009. Updated version Cited articles Citing articles E-mail alerts Reprints and Subscriptions Permissions Access the most recent version of this article at: doi:10.1158/1541-7786.MCR-09-0317 This article cites 261 articles, 110 of which you can access for free at: http://mcr.aacrjournals.org/content/7/12/1902.full.html#ref-list-1 This article has been cited by 23 HighWire-hosted articles. Access the articles at: /content/7/12/1902.full.html#related-urls Sign up to receive free email-alerts related to this article or journal. 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