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Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 Cancer Research Therapeutics, Targets, and Chemical Biology High Phosphoantigen Levels in Bisphosphonate-Treated Human Breast Tumors Promote Vg9Vd2 T-Cell Chemotaxis and Cytotoxicity In Vivo ne Benzaïd1,2, Hannu Mo € nkko € nen1,2, Verena Stresing1,2, Edith Bonnelye1,2, Jonathan Green4, Ismahe 4 zardin1,2 € nkko € nen , Jean-Louis Touraine3, and Philippe Cle Jukka Mo Abstract The nitrogen-containing bisphosphonate zoledronic acid (ZOL), a potent inhibitor of farnesyl pyrophosphate synthase, blocks the mevalonate pathway, leading to intracellular accumulation of isopentenyl pyrophosphate/ triphosphoric acid I-adenosin-50 -yl ester 3-(3-methylbut-3-enyl) ester (IPP/ApppI) mevalonate metabolites. IPP/ ApppI accumulation in ZOL-treated cancer cells may be recognized by Vg9Vd2 T cells as tumor phosphoantigens in vitro. However, the significance of these findings in vivo remains largely unknown. In this study, we investigated the correlation between the anticancer activities of Vg9Vd2 T cells and the intracellular IPP/ApppI levels in ZOL-treated breast cancer cells in vitro and in vivo. We found marked differences in IPP/ApppI production among different human breast cancer cell lines post-ZOL treatment. Coculture with purified human Vg9Vd2 T cells led to IPP/ApppI-dependent near-complete killing of ZOL-treated breast cancer cells. In ZOLtreated mice bearing subcutaneous breast cancer xenografts, Vg9Vd2 T cells infiltrated and inhibited growth of tumors that produced high IPP/ApppI levels, but not those expressing low IPP/ApppI levels. Moreover, IPP/ ApppI not only accumulated in cancer cells but it was also secreted, promoting Vg9Vd2 T-cell chemotaxis to the tumor. Without Vg9Vd2 T-cell expansion, ZOL did not inhibit tumor growth. These findings suggest that cancers-producing high IPP/ApppI levels after ZOL treatment are most likely to benefit from Vg9Vd2 T-cell– mediated immunotherapy. Cancer Res; 71(13); 4562–72. 2011 AACR. Introduction Nitrogen-containing bisphosphonates (NBP) are potent inhibitors of osteoclast-mediated bone resorption and can treat bone-loss disorders such as postmenopausal osteoporosis (1), aromatase inhibitor–associated bone loss, and cancer treatment–induced bone loss (2). In preclinical models, NBPs have direct and indirect antitumor properties (3). NBPs inhibit farnesyl pyrophosphate synthase (FPPS), thus blocking the mevalonate pathway and preventing prenylation of G-proteins (e.g., Ras and Rho). In addition to effects on bone, this can Authors' Affiliations: 1INSERM, UMR 1033, F-69372 Lyon; 2University of Lyon, F-69008 Lyon; 3Laboratory of Immunology and Transplantation, Edouard Herriot Hospital, Lyon, France; 4Novartis Pharma AG, Basel, Switzerland; and 5School of Pharmacy, University of Eastern Finland, Kuopio, Finland € nkko € nen have contributed equally to this work. Note: I. Benzaïd and H. Mo Note: Supplementary data for this article are available at Cancer Research Online (http://cancerres.aacrjournals.org/). zardin INSERM, UMR1033, UFR de Corresponding Author: Philippe Cle decine Lyon-Est (domaine Lae €nnec) Rue G. Paradin, 69372 Lyon cedex Me 08, France. Phone: 33-4-78-78-57-37; Fax: 33-4-78-77-87-72; E-mail: [email protected] doi: 10.1158/0008-5472.CAN-10-3862 2011 American Association for Cancer Research. 4562 inhibit tumor-cell invasion, proliferation, and adhesion (3). Additional studies suggest that NBPs may also inhibit angiogenesis (3). Importantly, there is now clinical evidence that adding the NBP zoledronic acid (ZOL) to endocrine therapy improves disease-free survival in estrogen-responsive early breast cancer (4,5) and that adding ZOL to neoadjuvant chemotherapy reduces residual invasive breast cancer tumor size (6). How ZOL mediates this activity is not understood. Emerging data suggest that NBPs have immunomodulatory properties (7,8), which may have therapeutic applications. Some NBPs can induce expansion of human Vg9Vd2 T cells, the dominant subset of gd T cells (8–10). NBP internalization by peripheral blood mononuclear cells (PBMC) inhibits FPPS, leading to intracellular accumulation of isopentenyl pyrophosphate (IPP) that, in turn, stimulates Vg9Vd2 T-cell proliferation in a Vg9Vd2 T-cell receptor (TCR)-dependent manner (11,12). The ATP analogue ApppI [triphosphoric acid I-adenosin-50 -yl ester 3-(3-methylbut-3-enyl) ester], which results from covalent binding of IPP and AMP (13), can also act as a phosphoantigen, stimulating the expansion of Vg9Vd2 T cells from PBMCs (14). In preclinical models, Vg9Vd2 T cells activated by NBPs have potent antitumor effects in vitro (7, 15–18), and Vg9Vd2 T cells expanded in vitro maintain antitumor activity upon adoptive transfer into immunodeficient mice inoculated with melanoma or pancreatic adenocarcinoma cells (15). Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 IPP/ApppI Mediates Vg9Vd2 T-cell Migration and Cytotoxicity ZOL also enhances Vg9Vd2 T-cell cytotoxicity in experimental models of chronic myelogenous leukemia and lung, colon, or bladder cancer (18–21). In addition, clinical evidence suggests anticancer effects of the Vg9Vd2 T cells in patients with lymphoid malignancies treated with the NBP pamidronate þ interleukin-2 (IL-2; refs. 7, 22), and in patients with castration-resistant prostate cancer or advanced metastatic breast cancer treated with ZOL þ IL-2 (23,24). A single dose of ZOL has also been shown to durably activate gd T cells in patients with breast cancer (25). Cancer cells may be especially vulnerable to Vg9Vd2 T cells (10, 11), even though the antitumor activity of Vg9Vd2 T cells against different tumor cells treated with NBPs varies (26). Interestingly, IPP/ApppI production after NBP treatment in different cell lines also varies (27), and these mevalonate metabolites could be recognized by Vg9Vd2 T cells as tumor phosphoantigens (10, 14), suggesting that the anticancer potency of Vg9Vd2 T cells might depend on intracellular IPP/ApppI levels in NBP-treated tumors. However, there is no in vivo evidence that a NBP can induce IPP/ApppI accumulation in tumors. In addition, the reasons why IPP/ApppIproducing tumors may become vulnerable to Vg9Vd2 T cells in vivo remain unexplored. In the present study, the correlation between the potency of Vg9Vd2 T cells to kill cancer cells and intracellular IPP/ApppI levels in ZOL-treated breast cancer cells was investigated in vitro and in vivo. Materials and Methods Drugs, cell culture, and animals Unlabeled and carbon 14 (14C)–labeled ZOL was provided by Novartis Pharma AG. Recombinant IL-2 was provided by Novartis Pharmaceuticals Ltd. Sterile stock bisphosphonate solutions were prepared in PBS (pH 7.4; Invitrogen). Five-week-old female nonobese diabetic severe combined immunodeficient (NOD/SCID) mice were purchased from Charles River Laboratories. All procedures involving animals, including their housing and care, the method by which they were killed, and experimental protocols, were conducted in accordance with a code of practice established by the local ethical committee (CREEA: Comite Regional d’Etique pour l’Experimentation Animale). Blood was donated by healthy volunteers or obtained from the Blood Transfusion Center (Etablissement Français du Sang). Human PBMCs were isolated after Ficoll–Paque (Amersham Biosciences) density gradient centrifugation. The Vg9Vd2 T cells were expanded by exposing PBMCs to 10mmol/L ZOL plus 100-U IL-2 for 14 days. Populations of Vg9Vd2 T cells were purified by positive selection of TCR gd cells using immunomagnetic cell sorting (AutoMACS Pro Separator, Miltenyi Biotec). Human breast cancer cell lines (T47D, MCF-7, BT-474, ZR75–1, MDA-MB-231, MDA-MB-435, MDA-MB-435s) were obtained from the American Type Culture Collection (ATCC)-LGC Promochem and used within 6 months. All cell lines were authenticated using short tandem repeat analysis. The human estrogen-receptor (ER)-negative B02 breast cancer cell line, a subpopulation of MDA-MB-231, was prepared as www.aacrjournals.org previously described (28). PBMCs and ZR-75–1 breast cancer cells were cultured in RPMI-1640 medium (ATCC) supplemented with 10% fetal bovine serum (Invitrogen) and penicillin/streptomycin (Invitrogen). BT-474 breast cancer cells were cultured in Hybri-Care medium (ATCC) supplemented with 1.5 g/L NaHCO3, 10% fetal bovine serum and penicillin/ streptomycin (Invitrogen). Other breast cancer cell lines were cultured in Dulbecco's modified Eagle's medium (DMEM) medium (Invitrogen) supplemented with 10% fetal bovine serum and penicillin/streptomycin. In vitro and in vivo Vg9Vd2 T-cell expansion and IFN-g measurement PBMCs were seeded in 24-well plates (1 106 cells/well) and then treated with vehicle (PBS) or ZOL (1, 10, or 100 mmol/L) IL-2 100 U/mL for 7, 14, 21, and 28 days. IL-2 was renewed at day 4 and then every 3 days. In vivo expansion of Vg9Vd2 T cells was carried out in NOD/SCID mice. PBMCs (3.5 107) were inoculated intraperitoneally (i.p.), and mice were treated with vehicle or ZOL (3, 10, or 30 mg/kg), i.p., and 10,000-U IL-2. Mice then received IL-2 plus vehicle or ZOL every 2 days for 14 days. On day 14, mice were sacrificed and peritoneal cells collected for analysis of Vg9Vd2 T cells. Percentages of Vg9Vd2 T cells in PBMCs and peritoneal cells were determined by flow cytometry (FACScan, Becton Dickinson) after immunostaining with anti–CD3-PE (BD Pharmingen) and anti–Vd2-TCR-FITC antibodies (Beckman Coulter). Human IFN-g in the serum from mice was measured using a commercial ELISA kit (Biosource). IPP/ApppI analysis ZOL-induced IPP/ApppI production was measured in PBMCs and breast cancer cells in vitro and in s.c. tumors in vivo. PBMCs (3 106) were exposed to PBS or ZOL (1, 10, or, 100 mmol/L) plus 100 U/mL IL-2, then cultured on 6-well plates for 1, 2, 4, 7, 11, and 14 days. T47D, MCF-7, and B02 breast cancer cells were seeded in 6-well plates at 1 106 cells/well overnight. Cells were pulse-treated with 25-mmol/L ZOL for 1 hour, then incubated without drug for 0 to 42 hours. Cells were then scraped and washed in PBS and extracted using ice-cold acetonitrile (300 mL) and water (200 mL) containing 0.25-mmol/L NaF and Na3VO4 to prevent degradation of IPP and ApppI. Tumor xenografts were collected from mice after sacrifice and snap-frozen in liquid nitrogen, pulverized, and extracted using ice-cold acetonitrile. IPP and ApppI in cell extracts were quantified by high-performance liquid chromatography negative ion electrospray ionization mass spectrometry (HPLC-ESI-MS; ref. 13). Cellular uptake assay for ZOL T47D, MCF-7, and B02 cells were seeded overnight to 10-cm Petri dishes at 4 106 cells/dish and then treated with 14 C-labeled ZOL for 1 hour. Cells were then rinsed with PBS, scraped, and extracted with acetonitrile and water. Extracts were separated by centrifugation (14,000g, 2 minutes). Precipitates were analyzed for total protein content by a modified Bradford procedure. The soluble acetonitrile/water extracts were evaporated and redissolved in 120-mL Milli-Q Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research 4563 Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 Benzaïd et al. water, then mixed with OptiPhase HiSafe3 scintillation cocktail (PerkinElmer Wallac) and evaluated by liquid scintillation (TriLux Microbeta, PerkinElmer Wallac). TV ¼ (m12m2)/2. At the end of the protocols, mice were sacrificed and tumors collected for immunohistochemistry and real-time PCR. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase analysis by Western blotting T47D, MCF-7, and B02 cells were treated with vehicle (0.5% DMSO) or 0.3-mmol/L lovastatin for 24 hours and then lysed in 100-mL cell lysis buffer [1% (vol/vol) Nonidet P-40 in 0.05M Tris-HCL containing 0.15-M NaCl, 1-mM EDTA, 0.05-M NaF and a cocktail of protease inhibitors (1-mM PMSF, 1-mg/ml aprotinin, 1-mg/mL leupeptin and 1-mmol/L NA3VO4)]. For each sample, 50-mg protein was used for SDS-polyacrylamide gel electrophoresis, and transferred onto a polyvinylidene difluoride (PVDF) membrane (Invitrogen), which was then washed with PBS/0.1% Tween and incubated overnight at 4 C with a rabbit polyclonal anti–3-hydroxy-3-methylglutarylcoenzyme A (HMG-CoA) reductase Ab (1/500 in 5% nonfat milk; Upstate). After washing, membranes were incubated with HRP-conjugated antirabbit Ab (GE Healthcare) and developed using Western Lightning Chemiluminescence (PerkinElmer LAS Inc.). As a control, washed membranes were incubated with horseradish peroxidase (HRP)-conjugated antimouse Ab (GE Healthcare) and then developed as before. Densitometric analysis of blots was carried out using Quantity One software (Bio-Rad Laboratories). Immunohistochemistry Tumors were embedded in Tissue-Tek (Sakura), snap-frozen in liquid nitrogen-cooled isopentane, and stored at–70 C. Frozen 7-mm sections were cut in a cryostat, air-dried, and fixed in cold acetone. After washing in PBS, tissue sections were preincubated with 1% goat serum. For detection of Vg9Vd2 T cells, tumor sections were incubated with a fluorescein isothiocyanate (FITC)-conjugated antihuman TCR d2 monoclonal Ab, diluted 1:20 in PBS/1% BSA/0.3% Triton X-100. Cell nuclei were stained with 40 ,6-diamidino2-phenylindole (DAPI; Roche). Tissue sections were rewashed and visualized by fluorescence microscopy (Axioskop 40; Zeiss). To measure tumor-cell proliferation, tumor sections were incubated with a rabbit polyclonal anti–Ki-67 Ab (Abcam). Experiments were carried out as previously described (28). The mitotic index was expressed as percentage of Ki-67–positive nuclei. Cytotoxicity assay T47D, MCF-7, and B02 breast cancer cells had different growth rates in culture. For cytotoxicity assessments, it was therefore necessary to adjust the cell number at the beginning of the experiment in order to have cell monolayers at a similar confluence at the time of the coculture with Vg9Vd2 T cells. In this respect, T47D (2 104 cells/well), MCF-7 (2 104 cells/ well), and B02 (7 103 cells/well) breast cancer cells were incubated overnight, then treated for 1 hour with vehicle (PBS) or ZOL (1–25 mmol/L). Cell monolayers were then washed; 18 hours later, breast cancer cells were cocultured with or without purified Vg9Vd2 T cells (cancer cell:Vg9Vd2 T-cell ratio was 1:12.5 or 1:25) for 4 hours or 24 hours. Viability was assessed by MTT assay. Experimental tumorigenesis Five-week-old female NOD/SCID mice were injected s.c. in the flank with 5 106 B02 or T47D cells in 100-mL PBS. For the ER-positive T47D cells, host mice were implanted with s.c. 60day–release pellets containing 1.7-mg 17b-estradiol (Innovative Research of America) 4 days before tumor-cell inoculation. Four weeks later, when B02 and T47D tumors had reached a volume of 50 mL, mice were randomly assigned to 4 treatment groups (n ¼ 6–7 mice/group): placebo (PBS); ZOL at 30 mg/kg body weight; human PBMCs (3.5 107) injected i.p. plus 10,000-U IL-2 administered alone or with 30mg/kg ZOL. In the relevant groups, IL-2 and ZOL in 0.5-mL PBS were administered i.p. every 2 days for 14 days. Tumor size was calculated by external measurement of the width (m1) and length (m2) of s.c. tumor xenografts using a Vernier caliper. Tumor volume (TV) was calculated using the equation 4564 Real-time PCR Total RNA was extracted from T47D and B02 tumors and infiltrating Vg9Vd2 T cells. Tumors were homogenized with a Polytron device (Kinematica). RNA was extracted using the nucleospin RNA II kit (Macherey–Nagel) followed by DNase digestion (Macherey-Nagel). Samples of total RNA (1.5–5 mg) were reverse-transcribed using Superscript II (Invitrogen). real-time PCR was carried out (IQ SYBR Green, Bio-Rad) with primers specific for the human housekeeping gene L32 (100 bp), a ribosomal protein used as an internal standard: 50 caaggagctggaagtgctgt; 30 cagctctttccacgatggc, and human TCR Vd2 (162 bp): 50 caaaccatccgtttttgtc; 30 cttgacag cattgtacttcc. We confirmed the linear range of amplification for all primers and products. Real-time reverse transcriptase (RT)-PCR was carried out using the Mastercycler EP system (SYBR Green; Realplex2). Amplimers were quantified in triplicate samples in the pool of 3 independent tumors for each gene and normalized to corresponding L32 values. Transwell migration assay T47D, MCF-7, and B02 breast cancer cells were seeded overnight to 6-well plates at 106 cells/well. The cells were then treated for 1 hour with PBS or 25-mmol/L ZOL 10-mmol/L lovastatin. Cells were then washed twice with PBS and cultured for 18 hours in DMEM þ 0.25% BSA. The conditioned medium from treated or untreated breast cancer cell lines was collected and centrifuged for use in migration assays. Migration assays were carried out in 24-well Transwell plates (Corning Costar) with 5-mm pore polycarbonate membrane. Before migration assays, Vg9Vd2 T cells were enriched by PBMC culture with 10-mmol/L ZOL plus 100 U IL-2 for 10 to 14 days. Purified populations of Vg9Vd2 T cells obtained by positive selection of TCR gd were resuspended at 3 106 cells/ 100 mL in assay buffer. A cell suspension (100 mL) was placed in the upper chamber of the Transwell inserts, and 600 mL of conditioned medium from breast cancer cell lines, plus Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research Cancer Research Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 IPP/ApppI Mediates Vg9Vd2 T-cell Migration and Cytotoxicity 1 mmol/L ApppI or 0.5 mmol/L IPP, were placed in the lower chamber. After incubation for 4 or 24 hours at 37 C, cells from the lower chamber were counted. Basal cell-culture medium was used as a control to measure random migration of Vg9Vd2 T cells in the absence of chemoattractant. The control was set to 100%, and the results obtained in the presence of a chemoattractant were expressed as a percentage of the control. Human cytokines released from vehicle- and ZOL-treated T47D and B02 cells were detected using RayBio Human Cytokine Ab Array C series 1000, designed to detect 120 cytokines (Ray Biotech). The array membranes were incubated overnight with conditioned medium (1.2 mL/1.2 mg protein) from cultured T47D and B02 cells treated or untreated with ZOL. Detection of immunoreactive spots was carried out using an enhanced chemiluminescence detection system. Human chemokines IL-8, IL-6, and monocyte chemoattractant protein-1 (MCP-1; eBioscience) released from vehicleand ZOL-treated T47D, MCF-7, and B02 cells were measured by ELISA. A Statistical analysis All data were analyzed using StatView software (version 5.0; SAS Institute Inc.). Pairwise comparisons were carried out by conducting a nonparametric Mann–Whitney U test. P values < 0.05 were considered statistically significant. All statistical tests were two-sided. Results and Discussion ZOL induces human Vg9Vd2 T-cell expansion in vitro and in vivo ZOL stimulated, in a time- and dose-dependent manner, expansion of Vg9Vd2 T cells from human PBMCs, peaking at day 14 with a 10-mmol/L ZOL concentration (Fig. 1A). These results are in accordance with previous reports showing that NBPs stimulate proliferation of Vg9Vd2 T cells in vitro (29). In addition, mass spectrometry revealed rapid IPP accumulation in PBMCs after 1–2 days of ZOL treatment (Fig. 1B), whereas ApppI was detected after 2–4 days (Fig. 1C). B C 90 80 10 μmol/L ZOL+IL-2 70 100 μmol/L ZOL+IL-2 40 20 10 μmol/L ZOL 100 μmol/L ZOL 60 50 40 30 20 10 14 21 28 2 nd 4 104 E 100 μmol/L ZOL 12 10 8 6 4 ndnd 7 11 ndnd nd 14 0 ndnd 1 nd nd 2 4 7 ndnd nd nd 11 14 Time, days 102 16% Vγ9Vδ2 T 101 102 103 2.7% Vγ9Vδ2 T 101 Tlymphocytes 10 μmol/L ZOL 14 Time, days Time, days D 16 104 7 1 nd 103 0 1 μmol/L ZOL 18 2 nd 0 0 20 1 μmol/L ZOL 6 60 1 μmol/L ZOL+IL-2 Apppl, pmol/106 cells IL-2 IPP, pmol/10 cells Proportion of Vγ9Vδ2T cells, % 80 101 102 103 104 101 102 103 104 Vγ9Vδ2 T cells Figure 1. ZOL-induced Vg9Vd2 T-cell expansion in vitro and in vivo and IPP/ApppI production in human PBMCs. A, PBMCs were treated with 1, 10, or 100 µmol/L of ZOL plus 100 U/mL of IL-2, or with IL-2 alone. Vg9Vd2 T-cell proliferation was analyzed by flow cytometry after 0- to 28-day culture. Data are expressed as mean SD of triplicate cultures from a representative donor. B and C, accumulation of IPP (B) and ApppI (C) in PBMCs after 1- to 14-day culture, detection limit 1 pmol/mg protein. Data are mean SD of duplicate cultures (representative donor). D and E, dot plot of flow cytometry from peritoneal cells of NOD/SCID mice receiving PBMCs and 10,000 U of IL-2 alone (D) or with 30 µg/kg of ZOL (E), both every 2 days for 14 days. Plots are representative of 5 mice. nd, not detected. www.aacrjournals.org Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research 4565 Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 Benzaïd et al. No reactivity of murine gd T cells to phosphoantigens such as IPP or ApppI has yet been shown, and human gd T cells do not recognize cells from animals other than humans (11, 30). Thus, murine PBMCs treated with an amino-bisphosphonate do not activate murine or human gd T cells. The effect of ZOL on Vg9Vd2 T-cell expansion was therefore studied in vivo after i.p. injection of human PBMCs into NOD/SCID mice and ZOL þ IL-2 treatment. ZOL stimulated expansion of Vg9Vd2 T cells such that they comprised up to 16% of T lymphocytes, versus 2.7% for IL-2 alone (Fig. 1D and E). This is explained by the fact that ZOL is internalized by antigen-presenting cells from human PBMCs where it induces the intracellular accumulation of IPP/ApppI and subsequent activation of Vg9Vd2 T-cell expansion (12), making our animal model most suitable for studying the role of ZOL in cancer immunotherapy in vivo. Moreover, although ZOL was administered more frequently in our model than the current clinical dosing regimen in humans, the dose given (30 mg/kg) was lower than the dosing in humans (100 mg/kg), supporting the clinical relevance of our findings. luminal breast cancer cell lines studied (T47D, MCF-7, BT-474, ZR-75–1) produced IPP/ApppI, whereas none (0/4) of the basal breast cancer cell lines tested (MDA-MB-231, B02, MDA-MB-435, and MDA-MB-435s) produced these phosphoantigens. In addition, we found that IPP/ApppI accumulation in ZOL-treated T47D cells was time-dependent, with IPP reaching a maximum concentration at 12 hours (1,052 pmol/ mg protein) and ApppI peaking at 24 hours (1,302 pmol/mg protein) (Fig. 2B). These results were in line with our previous findings showing that the basal MCF-10A and MDA-MB-436 breast cell lines produced low levels of IPP/ApppI after ZOL treatment (27). The higher IPP/ApppI production in luminal versus basal breast cancer cell lines is, to our knowledge, a novel observation. Three breast cancer cell lines having a high (T47D), medium (MCF-7), or low (B02) production of phosphoantigens were then selected for subsequent experiments. Fluid-phase endocytosis is the major route by which NBPs are internalized in macrophages and osteoclasts (31). Variations in endocytosis between the cancer cell lines might explain differences in IPP/ ApppI production induced by ZOL. Uptake of 14C-labeled ZOL was therefore measured in T47D, MCF-7, and B02 cells. Uptake was similar in T47D and MCF-7 cells, but 3-fold lower in B02 cells (Fig. 2C). In addition, we found a strong correlation between HMG-CoA reductase expression, a mevalonate pathway enzyme upstream of FPP synthase, and ZOL-induced IPP/ ApppI accumulation (Fig. 2D). As shown by Western blotting, lovastatin (an HMG-CoA reductase inhibitor) substantially increased HMG-CoA reductase protein levels in ER-positive T47D and MCF-7 cells (Fig. 2D). By contrast, HMG-CoA reductase was undetectable, and only a faint protein band was observed in lovastatin-treated ER-negative B02 cells ZOL induces IPP/ApppI production in human breast cancer cells in vitro Prior studies showed the intracellular accumulation of IPP and ApppI in NBP-treated cancer cell lines in vitro (10, 27). In our study, ZOL-induced IPP/ApppI production was quantified in a series of human breast cancer cell lines having a luminal [ER-positive and/or progesterone receptor (PR)-positive and Ki-67-positive] or basal (ER-, PR-, and HER2-negative) molecular subtype. Mass spectrometry analysis showed that IPP/ ApppI levels varied substantially among breast cancer cell lines after ZOL treatment (Fig. 2A). Specifically, 3 of the 4 B IPP Apppl 1,400 1,200 1,000 800 600 400 200 C <1 <1 0 nd nd 1,500 T47D, pmol/mg protein 1,600 IPP Apppl 1,200 900 600 300 0 T4 7D M C FBT 7 -4 7 ZR 4 M DA -75 M -MB 1 DA -4 -M 35 M B-4 DA 35 s M MB DA -2 3 -M 1 BBO 2 Accumulation, pmol/mg protein A 0 4 8 12 16 20 24 28 32 36 40 44 Time, h D Cellular uptake, pmol/mg protein 40 30 18 15 0 97 100 8 HMG-CoAR 20 Tubulin 10 0 4566 Band density T47D MCF-7 T47D MCF-7 BO2 Basal BO2 T47D MCF-7 Lovastatin BO2 Figure 2. IPP/ApppI accumulation induced by ZOL depends on activity of the mevalonate pathway and cellular uptake of ZOL. A, breast cancer cells were treated with 25-mmol/L ZOL for 1 hour, then cultured without drug for 18 hours (mean SD, n ¼ 12– 21); detection limit was 1 pmol/mg protein. B, T47D cells were treated with 25-mmol/L ZOL for 1 hour and samples collected 0 to 42 hours after drug removal (mean SD, n ¼ 3). C, cellular uptake of 14 C-labeled ZOL 1 hour after 25-mmol/L ZOL treatment (mean SD, n ¼ 3). D, bands of HMGCoA reductase (HMG-CoAR) and tubulin by Western blotting in cancer cell lines after treatment with 0.5% DMSO (basal) or 0.3mmol/L lovastatin for 24 hours. Band density of HMG-CoAR is normalized by tubulin. Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research Cancer Research Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 IPP/ApppI Mediates Vg9Vd2 T-cell Migration and Cytotoxicity addition, Vg9Vd2 T cells caused ZOL-treated MCF-7 cell death; concentrations of ZOL 10 mmol/L were required to prime MCF-7 cells for Vg9Vd2 T-cell–mediated cytotoxicity (Fig. 3D). In sharp contrast, Vg9Vd2 T cells were not cytotoxic against ZOL-treated B02 cells (Fig. 3F). Although human cancer cell lines exhibit susceptibility to Vg9Vd2 T-cell–mediated cytotoxicity upon NBP treatment, the in vitro antitumor activity of Vg9Vd2 T cells against tumor cells treated with NBPs varies greatly (10, 11, 15). For example, Vg9Vd2 T cells fail to efficiently kill a variety of human renal (ACHN, Caki-2, A-704) and gastric (MKN45, MKN74) cancer cell lines after NBP pretreatment (11). Here, our results strongly suggest that ZOL-induced IPP/ApppI accumulation in breast cancer cells was responsible for Vg9Vd2 T-cell– mediated cytotoxicity. In this respect, cotreatment of T47D cells with ZOL þ lovastatin almost completely eliminated IPP/ApppI phosphoantigen production by these cells and substantially reduced Vg9Vd2 T-cell cytotoxicity (Supplementary Fig. S1). It is therefore most conceivable that the lack of cytotoxicity of Vg9Vd2 T cells against some cancer cell lines is attributable to a low intracellular accumulation of phosphoantigens upon NBP treatment of cancer cells, likely because of the low activity level of the mevalonate pathway. (Fig. 2D). These results agree with data reported by Borgquist and colleagues (32) who showed that high HMG-CoA reductase expression correlated positively with ER expression in tumor tissue from patients with breast cancer. Altogether, these results show that IPP/ApppI production in breast cancer cells depends on cellular uptake of NBP and on the activity of the mevalonate pathway. Moreover, we suggest that luminal neoplastic mammary epithelial cells might be more sensitive to bisphosphonate therapy than basal neoplastic mammary epithelial cells. Vg9Vd2 T-cell cytotoxicity correlates with ZOL–induced IPP/ApppI accumulation in breast cancer cells in vitro and in vivo The antitumor potency of human Vg9Vd2 T cells against ZOL-treated breast cancer cell lines was first examined in vitro (Figs. 3A–3F). Incubation for 1h with ZOL (1–25 mmol/L) did not affect survival of T47D, MCF-7, and B02 cells (Figs. 3A, 3C, and 3E, respectively), whereas these bisphosphonate concentrations did induce intracellular IPP/ApppI accumulation in T47D and MCF-7 cells (Figs. 2A-B). Coculture of ZOL-treated T47D cells with purified Vg9Vd2 T cells led to dose-dependent cancer-cell death, which was statistically significant with ZOL at concentrations as low as 1 mmol/L for 1 hour (Fig. 3B). In – γδ T cells + γδ T cells B A 140 120 80 60 40 0 CTR 1 5 10 15 120 100 80 60 40 CTR 1 3 5 10 15 25 * 80 ** ** 60 40 20 CTR 1 3 5 10 15 ZOL, μmol/L E 0 25 CTR 1 120 100 100 Viability, % 125 75 50 3 5 10 15 25 15 25 ZOL, μmol/L F 25 80 60 40 20 CTR 1 3 5 10 ZOL, μmol/L www.aacrjournals.org ** ZOL, μmol/L 100 0 ** ** D 20 BO2 ** 40 120 0 ** 60 0 25 Viability, % Viability, % 3 ZOL, μmol/L C MCF-7 ** 80 20 20 Viability, % Figure 3. ZOL-induced IPP/ApppI accumulation in breast cancer cells correlates with Vg9Vd2 Tcell–mediated cancer-cell death. T47D, MCF-7, and B02 cells were pretreated with control (CTR; PBS) or ZOL 1 to 25 mmol/L for 1 hour, then cultured without drug for 18 hours. After incubation, cells were cocultured without (A, C, E) or with (B, D,F) purified Vg9Vd2 T cells for 24 hours. The ratio of cancer cells to Vg9Vd2 T cells was 1:12.5. A—F are representative of 3 independent experiments (mean SD; *, P < 0.05; **, P < 0.01). 100 100 Viability, % T47D Viability, % 120 15 25 0 CTR 1 3 5 10 ZOL, μmol/L Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research 4567 Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 Benzaïd et al. We next conducted in vivo experiments to examine the contribution of IPP/ApppI accumulation in breast tumors to Vg9Vd2 T-cell cytotoxicity. Earlier experimental in vivo studies used human Vg9Vd2 T cells expanded in vitro and then purified before inoculation (15, 18, 19, 20). Here, we showed that ZOL þ IL-2 treatment induced Vg9Vd2 T-cell expansion from human PBMCs injected i.p. into NOD/SCID mice (Fig. 1E). In the clinic, it has been recently shown that the treatment of patients with advanced breast cancer with ZOL and low-dose IL-2 triggers Vg9Vd2 T-cell amplification in vivo (24). We therefore chose to use this therapeutic strategy to treat tumor-bearing animals. NOD/SCID mice bearing sub- cutaneous breast cancer xenografts were inoculated with human PBMCs, with expansion of Vg9Vd2 T cells in vivo (Fig. 4). Treatment with ZOL alone or PBMCþIL-2 did not inhibit s.c. tumor growth (Fig. 4A and B). In contrast, PBMC þ IL-2 þ ZOL completely blocked growth progression of T47D tumors, compared with that observed in placebo-treated animals (P < 0.01; Fig. 4A). In addition, in situ immunodetection of the proliferation marker Ki-67 nuclear antigen in T47D tumors from mice treated with PBMC þ IL-2 þ ZOL showed drastic reduction in proliferative index versus tumors from placebo-treated mice (Fig. 4C). However, this treatment did not inhibit growth or proliferative index of B02 s.c. tumors RT-PCR Human PBMCs Tumor cells IHC 2 Weeks 4 Weeks ZOL ± IL-2 A B T47D tumors ns 100 ** 50 W4 W6 Placebo W4 W6 ZOL W4 W6 PBMC +IL-2 Ki67 index, (%) C 21 18 15 12 9 6 3 0 W4 W6 PBMC +IL-2 +ZOL Tumor volume (mm3) ns 150 0 BO2 Tumors 250 ns ** Placebo ZOL E PBMC +IL-2 PBMC +IL-2 +ZOL 150 100 50 40 35 30 25 20 15 10 5 0 4 3 2 ns 1 Placebo ZOL ns PBMC +IL-2 PBMC +IL-2 +ZOL x40 Relative Vγ9Vδ2 expression Relative Vγ9Vδ2 expression W4 W6 PBMC +IL-2 W4 W6 PBMC +IL-2 +ZOL * Placebo ns ns ZOL PBMC +IL-2 PBMC +IL-2 +ZOL ns ns ns ZOL PBMC +IL-2 PBMC +IL-2 +ZOL 6 ** 5 G 4568 W4 W6 ZOL F 6 0 W4 W6 Placebo D ns ns ns ns 200 0 Ki67 index, (%) Tumor volume (mm3) 200 5 4 3 2 1 0 Placebo Figure 4. Cytotoxic effect of Vg9Vd2 T cells against T47D and B02 breast cancer s.c. tumor xenografts. Mice were inoculated s.c. with T47D or B02 cells. Four weeks after tumor cell inoculation, when tumors became palpable, mice were engrafted with PBMCs from healthy human adult blood donors. In addition, mice were treated with IL-2 ZOL (30 mg/kg) every 2 days for 2 weeks. T47D (A) and B02 (B) tumor growth was determined at weeks 4 and 6 after tumor cell inoculation, by measurement of the tumor volume with a Vernier caliper. T47D (C) and B02 (D) Ki-67 indices were assessed by immunohistochemistry. The relative expression of Vg9Vd2 T cells in T47D (E) and B02 (F) tumors was assessed by RT-PCR. G, presence of Vg9Vd2 T cells in T47D tumors from the placebo and PBMCþIL-2þZOL groups. Tumor sections were stained with TCR Vd2 (green) and DAPI (nuclei, blue). Results are mean SD of 6 to 7 mice per group. ns, not significant; *, P < 0.05; **, P < 0.01 compared with placebo. x40 Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research Cancer Research Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 IPP/ApppI Mediates Vg9Vd2 T-cell Migration and Cytotoxicity Human PBMCs MS 2 Weeks ZOL ± IL-2 T47D Tumors Tumor volume (mm3) after 2-week treatment 200 ns 150 ns ** 50 0 Placebo ZOL PBMC +IL-2 100 Standards Apppl IPP PBMC +IL-2 +ZOL NH2 22 80 O 40 20 O OH O OH O O OH OH O O O O O 60 OH O CH2 O OH H H 4x 159 A H H OH OH Placebo 100 80 60 40 20 B 100 Relative abundance (%) 4 Weeks Relative abundance (%) Tumor cells Relative abundance (%) Relative abundance (%) 48 hours after the last ZOL dose in PBMC þ IL-2 þ ZOLtreated mice (0.7 pmol; 16 nmol/L), whereas ApppI levels were measured (0.11 pmol; 2.5 nmol/L; Fig. 5C). Of note, IPP and ApppI were also detected in T47D tumor extracts from mice treated with ZOL alone. In contrast, ZOL-induced IPP/ApppI was not detected in B02 tumor xenografts (not shown). These data, to the best of our knowledge, show for the first time that s.c. tumors can produce IPP/ApppI after ZOL administration, showing the uptake of the NBP into tumor cells in vivo. If IPP/ApppI had been produced by tumorinfiltrating cells (e.g., macrophages), we would have expected IPP/ApppI also to be produced in B02 tumors, contrary to what we observed in vivo. It is interesting that Guenther and colleagues (33) recently reported, based on their use of a mouse xenograft model for plasmacytoma, that the treatment of animals with ZOL leads to accumulation of unprenylated Rap1A (a surrogate marker of the inhibitory effect of NBP on the mevalonate pathway) in plasma cell tumors ex vivo. These findings (33), along with our present data, provide evidence for (Fig. 4B and D). Of note, Vg9Vd2 T-cell infiltrates were detected in T47D but not B02 tumors from mice treated with PBMC þ IL-2 þ ZOL (Fig. 4E–G), as judged by both RT–PCR and immunohistochemistry. Moreover, serum levels of human IFN-g were high in T47D-tumor-bearing mice treated with PBMCs þ IL-2 þ ZOL (942 240 pg/mL, n ¼ 5) and moderate in animals treated with PBMCs þ IL-2 (563 370 pg/mL, n ¼ 5), whereas the cytokine was not detected in animals treated with placebo or ZOL alone, showing that Vg9Vd2 T cells were activated in vivo. Because Vg9Vd2 T cells infiltrated s.c. T47D tumor xenografts in mice treated with PBMC þ IL-2 þ ZOL (Fig. 4E and 4G), IPP/ApppI was measured in tumor extracts by mass spectrometry. As expected, IPP and ApppI were barely detectable in T47D tumors from placebo-treated mice (Fig. 5A), whereas IPP levels were substantial 24 hours after the last ZOL dose in mice treated with PBMC þ IL-2þ ZOL (3.7 pmol; 82 nmol/L) (Fig. 5B). By contrast, ApppI remained undetectable at 24 hours. Conversely, lower IPP levels were detected at ZOL, 24 h 100 80 60 40 20 C ZOL, 48 h 100 80 60 40 20 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Time (min) Time (min) IPP, m/z 245 → 159 Apppl, m/z 574 → 408 Figure 5. Mass spectrometry analysis of IPP and ApppI in T47D breast cancer s.c. tumor xenografts. Identification of IPP and ApppI in T47D tumors of placebo- and ZOL-treated mice was carried out by high-performance liquid chromatography negative ion electrospray-ionization mass spectrometry. Selected reaction monitoring chromatograms are shown. They correspond to tumor extracts obtained from placebo-treated mice (A) and animals that received PBMC þ IL-2 þ ZOL whose tumors were collected 24 hours (B) and 48 hours (C) after the last ZOL injection. Similar chromatograms were obtained with tumor extracts from mice treated with ZOL alone. Tumor extracts were spiked with 1.35-pmol IPP and 0.11-pmol ApppI. IPP and ApppI chromatograms are drawn on the same scale (standards). www.aacrjournals.org Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research 4569 Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 Benzaïd et al. medium from T47D cells treated with ZOL þ lovastatin resulted in less migration of Vg9Vd2 T cells (Fig. 6C). To clarify whether IPP/ApppI acted as migration factors for Vg9Vd2 T cells, we used mass spectrometry to measure IPP levels in conditioned medium from ZOL-treated breast cancer cell lines (T47D, MCF-7, B02). We found substantial IPP levels in conditioned medium from ZOL-treated T47D and MCF-7 cells, but not B02 cells (data not shown). Moreover, 0.5-mmol/L IPP or 1-mmol/L ApppI significantly stimulated gd T-cell migration (Fig. 6C). Because ApppI can be converted into IPP on hydrolysis by nucleotide pyrophosphatases (14), it also may be processed into IPP for subsequent recognition by the Vg9Vd2 TCR. The cytokines IL-6, IL-8, and MCP-1 are also gd T-cell chemoattractants (30). However, we found no differences in these or any other cytokines in a human cytokine antibody array of conditioned medium from untreated or ZOL-treated T47D, MCF-7, and B02 cells (Fig. 6D). Although B02 cells produced a greater range of cytokines than T47D cells, cytokine profiles were similar for ZOL-treated or a direct uptake of ZOL in tumor cells in vivo. However, in our breast cancer model, ZOL treatment without PBMC þ IL-2 (i.e., without Vg9Vd2 T-cell expansion) did not inhibit tumor growth, showing the important role of human Vg9Vd2 T cells in the antitumor activity of NBPs. IPP and ApppI released by breast cancer cells are chemotactic factors for Vg9Vd2 T cells In our model, ZOL was able to induce recruitment of Vg9Vd2 T cells to T47D tumors. We therefore investigated the ability of breast cancer cells treated in vitro with ZOL to promote Vg9Vd2 T-cell migration. Using conditioned medium from untreated breast cancer cell lines (T47D, MCF-7, B02) in Transwell migration assays, we observed significantly enhanced migration of Vg9Vd2 T cells after 4 hours (not shown) and 24 hours (Fig. 6A; P < 0.05 and P < 0.01) versus assay buffer. Migration of Vg9Vd2 T cells was much higher with conditioned medium from ZOL-treated T47D and MCF-7 breast cancer cells (Fig. 6B and C). In addition, conditioned B 180 ** 200 * Cell migration (%) 250 * 150 100 50 *** ns 140 120 100 80 60 40 Control D T47D, MCF-7, CM CM – + – T47D CM T47D CTR * ZOL + – MCF-7 CM 100 Angiogenin + Control –ZOL +ZOL +ZOL +LOV BO2 CM – 1 1 Angiogenin GDNF, GM-CSF IGFBP-1 – + 2 2 MCP-1 – 2 + 2 GRO, GRO-α IL-8 sTNF-R1 GRO, GRO-α + + – IL-6 + MCP-1 TIMP-1, TIMP-2 – Apppl T47D, CM IGFBP-4 + IPP E + – ns 0 + ZOL CTR 1 * 150 B02 1 ** 200 50 0 ZOL BO2 CM ** 250 20 0 – 300 *** 160 10,000 Secreted cytokine (pg/mL) 300 Cell migration (% of control) C Cell migration (% of control) A IL-6 IL-8 1,000 MCP-1 100 10 1 nd T47D, CM nd MCF-7, CM BO2, CM uPAR, VEGF TIMP-1, TIMP-2 Figure 6. IPP and ApppI induce chemotactic migration of Vg9Vd2 T cells. Purified Vg9Vd2 T cells isolated from ZOL-stimulated PBMCs by positive selection of TCR-gd cells were tested in a Transwell assay for their capacity to migrate (A) toward conditioned medium (CM) from T47D, MCF-7, and B02 cell lines compared with assay medium alone; (B) toward CM from ZOL-treated T47D, MCF-7, and B02 cells versus CM from untreated cells; or (C) toward CM from ZOL-treated T47D cells lovastatin and 0.5-mmol/L IPP or 1-mmol/L ApppI added in the medium, or compared with assay medium alone. Data represent mean percentage migration from 2 independent experiments SD. *, P < 0.05; **, P < 0.01; and ***, P < 0.001 using pairwise comparisons with the assay medium or CM from untreated cells. ns, not significant. D, detection of cytokines produced in the supernatant by cultured, untreated (control; CTR), and ZOL-treated T47D and B02 cells using 2 human cytokine antibody array membranes (1 and 2) designed to detect altogether 120 human cytokines. E, IL-6, IL-8, and MCP-1 secretion in CM of T47D, MCF-7, and B02 cells, using ELISA. 4570 Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research Cancer Research Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 IPP/ApppI Mediates Vg9Vd2 T-cell Migration and Cytotoxicity untreated cells (Fig. 6D). By ELISA, untreated B02 cells (control) produced more IL-8 and MCP-1 compared with T47D or MCF-7 control cells (Fig. 6E); IL-6 was detected only in B02 cells. In conclusion, our study shows for the first time that ZOL induces the production of IPP/ApppI phosphoantigens by breast tumors in vivo, which, in turn, promote chemotaxis and cytotoxicity of Vg9Vd2 T cells. These results provide some support for an adjuvant role of NBPs in breast cancer. There is now clinical evidence that adding ZOL to endocrine therapy improves disease-free survival in ER-responsive early breast cancer (4,5). ZOL has also been shown to durably activate gd T cells in patients with breast cancer (25). The immunomodulating role of NBPs on human gd T cells might explain, at least in part, the anticancer effects of ZOL observed in these adjuvant clinical trials. Overall, our findings suggest that cancers producing high IPP/ApppI levels after ZOL treatment are most likely to benefit from Vg9Vd2 T-cell–mediated immunotherapy. Disclosure of Potential Conflicts of Interest P. Clezardin has served on advisory boards for Novartis and Amgen. J. Green is a consultant for Novartis and holds stock in the company. Acknowledgments The authors thank Catherine Browning, PhD, ProEd Communications, Inc., Beachwood, Ohio, for her editorial assistance with this manuscript and Novartis Pharmaceuticals Corporation for financial support. We also thank the nurses from Edouard Herriot Hospital for their valuable help. Grant Support P. Clezardin has received lecture fees and a research grant from Novartis; and is supported by INSERM, the University of Lyon, and the Ligue Regionale contre le Cancer. H. M€ onkk€ onen is supported by Inserm (Poste Vert). J. M€ onkk€ onen is supported by the Academy of Finland. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Received October 26, 2010; revised April 27, 2011; accepted May 4, 2011; published OnlineFirst June 6, 2011. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Delmas PD. Treatment of postmenopausal osteoporosis. Lancet 2002;359:2018–26. Coleman RE, McCloskey EV. Bisphosphonates in oncology. Bone In press 2011. zardin P. Bishosphonates’ antitumor activity: an unravelled side of Cle a multifaceted drug class. Bone 2011;48:71–9. Gnant M, Mlineritsch B, Schippinger W, Luschin-Ebengreuth G, € stlberger S, Menzel C, et al. Endocrine therapy plus zoledronic Po acid in premenopausal breast cancer. N Engl J Med 2009;360:679–91. Eidtmann H, de Boer R, Bundred N, Llombart-Cussac A, Davidson N, Neven P, et al. Efficacy of zoledronic acid in postmenopausal women with early breast cancer receiving letrozole: 36 months results of the ZO-FAST study. Ann Oncol 2010;21:2188–94. Coleman RE, Winter MC, Cameron D, Bell R, Dodwell D, Keane MM, et al. The effects of adding zoledronic acid to neoadjuvant chemotherapy on tumour response: exploratory evidence for direct anti-tumour activity in breast cancer. Br J Cancer 2010;102:1099–105. Kunzmann V, Bauer E, Feurle J, Weissinger F, Tony HP, Wilhelm M. Stimulation of gammadelta T cells by aminobisphosphonates and induction of antiplasma cell activity in multiple myeloma. Blood 2000;96:384–92. Miyagawa F, Tanaka Y, Yamashita S, Minato N. Essential requirement of antigen presentation by monocyte lineage cells for the activation of primary human gamma delta T cells by aminobisphosphonate antigen. J Immunol 2001;166:5508–14. Dieli F, Gebbia N, Poccia F, Caccamo N, Montesano C, Fulfaro F, et al. Induction of gammadelta T-lymphocyte effector functions by bisphosphonate zoledronic acid in cancer patients in vivo. Blood 2003;102: 2310–1. Gober HJ, Kistowska M, Angman L, Jeno P, Mori L, De Libero G. Human T cell receptor gammadelta cells recognize endogenous mevalonate metabolites in tumor cells. J Exp Med 2003;197:163–8. Tanaka Y. Human g T cells and tumor immunotherapy. J Clin Exp Hematopathol 2006;46:11–23. Roelofs AJ, Jauhiainen M, Monkkonen H, Rogers MJ, Monkkonen J, Thompson K. Peripheral blood monocytes are responsible for gammadelta T cell activation induced by zoledronic acid through accumulation of IPP/DMAPP. Br J Haematol 2009;144:245–50. Monkkonen H, Auriola S, Lehenkari P, Kellinsalmi M, Hassinen IE, €la €inen J, et al. A new endogenous ATP analog (ApppI) inhibits Vepsa the mitochondrial adenine nucleotide translocase (ANT) and is responsible for the apoptosis induced by nitrogen-containing bisphosphonates. Br J Pharmacol 2006;147:437–45. www.aacrjournals.org 14. Vantourout P, Mookerjee-Basu J, Rolland C, Pont F, Martin H, Davrinche C, et al. Specific requirements for Vgamma9Vdelta2 T cell stimulation by a natural adenylated phosphoantigen. J Immunol 2009;183:3848–57. € ller M. Characterization of tumor 15. Kabelitz D, Wesch D, Pitters E, Zo reactivity of human V gamma 9V delta 2 gamma delta T cells in vitro and in SCID mice in vivo. J Immunol 2004;173:6767–76. 16. Marten A, Lilienfeld-Toal M, Buchler MW, Schmidt J. Zoledronic acid has direct antiproliferative and antimetastatic effect on pancreatic carcinoma cells and acts as an antigen for delta2 gamma/delta T cells. J. Immunother 2007;30:370–7. 17. Mattarollo SR, Kenna T, Nieda M, Nicol AJ. Chemotherapy and zoledronate sensitize solid tumour cells to Vgamma9Vdelta2 T cell cytotoxicity. Cancer Immunol Immunother 2007;56:1285–97. 18. Sato K, Kimura S, Segawa H, Yokota A, Matsumoto S, Kuroda J, et al. Cytotoxic effects of gammadelta T cells expanded ex vivo by a third generation bisphosphonate for cancer immunotherapy. Int J Cancer 2005;116:94–9. 19. Todaro M, D'Asaro M, Caccamo N, Iovino F, Francipane MG, Meraviglia S, et al. Efficient killing of human colon cancer stem cells by g T lymphocytes. J Immunol 2009;182:7287–96. 20. Yuasa T, Sato K, Ashihara E, Takeuchi M, Maita S, Tsuchiya N, et al. Intravesical administration of gamma delta T cells successfully prevents the growth of bladder cancer in the murine model. Cancer Imunol Immunother 2009;58:493–502. 21. D'Asaro M, La Mendola C, Di Liberto D, Orlando V, Todaro M, Spina M, et al. Vgamma9Vdelta2 T lymphocytes efficiently recognize and kill zoledronate-sensitized, imatinib-sensitive, and imatinib-resistant chronic myelogenous leukemia cells. J Immunol 2010;184: 3260–8. 22. Wilhelm M, Kunzmann V, Eckstein S, Reimer P, Weissinger F, Ruediger T, et al. Gammadelta T cells for immune therapy of patients with lymphoid malignancies. Blood 2003;102:200–6. 23. Dieli F, Vermijlen D, Fulfaro F, Caccamo N, Meraviglia S, Cicero G, et al. Targeting human {gamma}delta} T cells with zoledronate and interleukin-2 for immunotherapy of hormone-refractory prostate cancer. Cancer Res 2007;67:7450–7. 24. Meraviglia S, Eberl M, Vermijlen D, Todaro M, Buccheri S, Cicero G, et al. In vivo manipulation of Vgamma9Vdelta2 T cells with zoledronate and low-dose interleukin-2 for immunotherapy of advanced breast cancer patients. Clin Exp Immunol 2010;161:290–7. 25. Santini D, Martini F, Fratto ME, Galluzzo S, Vincenzi B, Agrati C, et al. In vivo effects of zoledronic acid on peripheral gammadelta Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research 4571 Published OnlineFirst June 6, 2011; DOI:10.1158/0008-5472.CAN-10-3862 Benzaïd et al. T lymphocytes in early breast cancer patients. Cancer Immunol Immunother 2009;58:31–8. 26. Morita CT, Jin C, Sarikonda G, Wang H. Nonpeptide antigens, presentation mechanisms, and immunological memory of human Vgamma2Vdelta2T cells: discreminating friend from foe through the recognition of prenyl pyrophosphate antigens. Immunol Rev 2007;215:59–76. € nkko € nen H, Kuokkanen J, Holen I, Evans A, Lefley DV, Jauhiainen 27. Mo M, et al. 2008. Bisphosphonate-induced ATP analog formation and its effect on inhibition of cancer cell growth. Anticancer. Drugs 19: 391–399. 28. Peyruchaud O, Winding B, Pecheur I, Serre CM, Delmas P, Clezardin P. Early detection of bone metastases in a murine model using fluorescent human breast cancer cells: application to the use of the bisphosphonate zoledronic acid in the treatment of osteolytic lesions. J Bone Miner Res 2001;16:2027–34. 4572 29. Sanders JM, Ghosh S, Chan JM, Meints G, Wang H, Raker AM, et al. Quantitative structure-activity relationships for gammadelta T cell activation by bisphosphonates. J Med Chem 2004;47:375–84. 30. Bonneville M, O’Brien RL, Born WK. g T cell effector functions: a blend of innate programming and acquired plasticity. Nat Rev Immunol 2010;10:467–78. 31. Thompson K, Rogers MJ, Coxon FP, Crockett JC. Cytosolic entry of bisphosphonate drugs requires acidification of vesicles after fluidphase endocytosis. Mol Pharmacol 2006;69:1624–32. n F, Anagnostaki L, Goldman M, Gaber A, 32. Borgquist S, Djerbi S, Ponte et al. HMG-CoA reductase expression in breast cancer is associated with a less aggressive phenotype and influenced by anthropometric factors. Int J Cancer 2008;123:1146–53. 33. Guenther A, Gordon S, Tiemann M, Burger R, Bakker F, Green JR, et al. The bisphosphonate zoledronic acid has antimyeloma activity in vivo by inhibition of protein prenylation. Int J Cancer 2010;126:239–46. Cancer Res; 71(13) July 1, 2011 Downloaded from cancerres.aacrjournals.org on August 30, 2011 Copyright © 2011 American Association for Cancer Research Cancer Research