Download Breast Cancer Pathways 101

11/11/11 Molecular pathways in breast cancer Elgene Lim. M.D., Ph.D. Women’s Cancers Program Dana-­‐Farber Cancer InsCtute This is not what this talk is about 1 11/11/11 Overview • 
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Common themes in intracellular signalling in cancer HER2+ -­‐ HER2/PI3K/AKT signaling ER+ -­‐ Hormone signaling Triple NegaCve ! BRCA 1 & 2 mutant – DNA repair pathway •  Others ! Stromal pathways: VEGF and HIF signaling ! Apoptosis pathways ! Tumor IniCaCng cells and Epithelial Mesenchymal TransiCon IntroducCon and Themes 2 11/11/11 LimitaCons of current approaches to cancer therapy •  Empiric approach to choice of chemotherapy •  Toxicity due to relaCvely non-­‐selecCve targeCng •  Recent paradigm shi0 !  TargeCng oncogenic pathways and idenCfying predicCve biomarkers !  Altering the tumor niche !  ShiZing the balance between apoptosis and survival !  TargeCng the cancer stem cell •  Key hurdles !  OZen ineffecCve alone !  Obtaining effecCve in vivo doses, isoform specificity !  IdenCficaCon of appropriate biomarkers/ appropriate subgroups !  AcquisiCon of therapeuCc resistance and relapse 3 11/11/11 Acquired CapabiliCes of Cancer RaConal targets for therapy Hanahan & Weinberg. Cell 2011
Intracellular networks in cancer cells Hanahan & Weinberg. Cell 2011
4 11/11/11 Signalling: systems or discrete pathways? Cross Talk Func.onal redundancy Oncogenic AddicCon Feedback loops • 
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Majority of cancers Require targeCng of mulCple pathways • 
Minority of cancer • 
TargeCng the archilles heel Basis of resistance Response to targeted tx is modest unless they are administered concomitantly with other modali8es TargeCng the hallmarks of cancer Hanahan & Weinberg. Cell 2011 5 11/11/11 Intracellular signalling pathways HER2 signalling Signalling Cascade Ligand
RTKs
Dimerization
Intracellular
SIgnaling
Gene activation
Effector mechanisms
Outcomes
EGF
ARG
EGFR
Ras/
Raf/
MEK
Cyclin
D1/2
HER
Wnt
IGF1-R
IRS/
SHC
PI3K/
AKT/
mTOR
E2
Frizzled/
LRP5/6
GSK/
β-Cat/
APC
ER
MYC
Bcl 2
VEGF
Metabolism Cell growth Ins/
IGF1
NRG
β-Cat/
TCF
ERE
HIF
Survival/ Apoptosis ProliferaCon DifferenCaCon Angiogenesis MigraCon 6 11/11/11 HER2 and inter-­‐related signalling pathways Overexpression DimerizaCon Morrow et al. Breast Can Res 2009 TargeCng the EGFR family Monoclonal anCbodies Ab-­‐cytotoxic conjugate Tyrosine Kinase Inhibitors Alvarez et al. JCO 2010 7 11/11/11 UpregulaCon of HER3 and resistance to anC-­‐HER2 therapies HER2 blockade Feedback loop HER3 upregulaCon = + Cross talk Resistance Abramson & Arteaga. Clin Cancer Res 2011 PI3K/mTOR/Akt pathway Ras/Raf/MAPK pathway 8 11/11/11 MulCple aberraCons lead to PI3K pathway acCvaCon S6K-­‐IRS1 Feedback loop ê Sites of muta8on/dele8on that result in aberrant ac8va8on PI3KCA ac*va*ng muta*on Uterus 30% Breast 25% Colon 15% Bladder 15% Di Cosimo & Baselga. Clin Can Res 2009 mTOR regulates cell proliferaCon and metabolism in response to environmental factors Alvarez et al. JCO 2010 9 11/11/11 Subtype specific PI3K pathway aberraCon PIK3CA
AKT1
PDK1
PTEN
PTEN
INPP4B
RAS/RAF
P53
mut
mut
amp
mut
protein loss
del
mut
mut
Breast
339/1261
27/1008
27/129
46/121
(26.9%)
(2.6%)
(20.9%)
6/209
(2.3%)
2/406
(total)
(22.7%)
Breast
101/305
6/232
16/79
4/131
10/69
HR+
(33.1%)
(2.6%)
(23.2%)
(3.4%)
(14.5%)
Breast
24/98
HER2+
(24.5%)
Breast
21/262
TNBC
(8%)
Ovarian
Endometrial
0/75
0/111
2/332
2/332
(0.6%)
(0.6%)
73/246
3/150
(30%)
(2%)
Concept of pathway aberraCon Highlighted > 20% Not included: PIK3CA amp 5/19
(26.3%)
2/15
(13.3%)
Rare
Rare
0/33
0/41
4/132
(3%)
20/76
(26%)
25/110
2/18
(11%)
11/21
(52%)
≈ 40%
≈ 50%
≈ 20%
(0.5%)
Rare
(24.6%)
14/23
Rare
(60.9%)
12/22
≈ 60%
≈ 20%
≈ 8%
(38%)
18/73
(63.6%)
12/428
90/132
(2.8%)
(68%)
44/206
9/96
(21%)
(9%)
Unpublished data, SU2C collaborators TargeCng the PI3K pathway PotenCally overcomes feedback acCvaCon of PI3K with mTOR inhibiCon alone PKI 587
Current agents target primarily p110α isoform 10 11/11/11 Feedback Loops Feedback activation following
Pi3K inhibition
Reciprocal activation of MEK and PI3K pathways following
inhibition
PI3K inhibitor + MEK inhibitor trials underway in SU2C
O Brien et al. Clin Can Res 2010 Rexer et al. Clin Can Res 2009 Current PI3K pathway inhibitors in clinical trials Hernandez-­‐Aya & Gonzalez-­‐Angulo.. Oncologist 2011 11 11/11/11 Ras/Raf/MAPK pathway Roberts & Der. Oncogene 2008 Ras mutaCons in human cancer Ac8va8ng muta8ons: impair intrinsic GTPase ac8vity, RAS accumulate in ac8ve GTP bound form. Approx 30% human cancers. Cell context and level of expression determine func8onal consequence. Schubbert S et al. NRC 2007 12 11/11/11 IGF1 signalling in human cancer Breast Prostate Colon Liver Melanoma GBM Mesothelioma Myeloma Sachdev & Yee. Mol Ther 2007 Hormone receptor pathway 13 11/11/11 Growth pathways in ER+ cells Aromatase Inhibitors Tamoxifen Fulvestrant Co-­‐targe.ng pathways Hormonal Tx + EGFR inhibitor HER2 inhibitor PI3K inhibitor IGF-­‐1R inhibitor Survival ProliferaCon DifferenCaCon Johnston. Clin Breast Can 2009 Regulatory network in ER-­‐HER2+AR+ breast cancer AR
Androgen metabolism
SRD5A1, UGT2B28, etc
Wnt7b
PI3K
Nuclear
!-catenin
AR AR
ERBB3/2
p-Akt
p27Kip
p21Cip
Targets
Ni et al, Cancer Cell 2011 14 11/11/11 DNA repair pathway BRCA1 mutaCon and cancer •  220 kDa nuclear protein •  Tumour suppressor gene •  Loss of funcCon mutaCons predispose to cancer !  Majority truncaCng nonsense + frameshiZ mutaCons !  Asso genomic instability Lifetime risk
BRCA1
General
Population
•  Basal/Triple negaCve Phenotype Breast Ca
65%
10%
Ovarian Ca
40%
1-2%
•  MutaCons are rare in sporadic tumours •  PreventaCve strategies: ProphylacCc mastectomy and ovariectomy 15 11/11/11 BRCA and DNA repair BRCA1 •  Broad cellular role •  Signaling of DNA damage !  Phosphorylated by kinases central to DNA damage response, ATM/ATR and CHK •  DNA repair !  homologous recombina8on !  nucleoCde-­‐excision repair BRCA2 •  Restricted to DNA recombinaCon and repair processes !  homologous recombina8on; RegulaCon of RAD51 acCvity SyntheCc lethality: targeCng a weakness in DNA repair 16 11/11/11 Resistance to carboplaCn through BRCA2 reversion mutaCon Ashworth. Cancer Res 2008 Stromal signaling pathways Angiogenesis/VEGF signaling 17 11/11/11 TargeCng the tumor micro-­‐enviroment Hanahan & Weinberg. Cell 2011 AnC-­‐angiogenic strategies 18 11/11/11 TargeCng the HIF pathway Kaelin W. Cancer 2009 Apoptosis pathway 19 11/11/11 ApoptoCc Pathways Intrinsic pathway Extrinsic pathway Cytokines Death ligand Microenvironment GlucocorCcoids Cell surface receptors Death receptor
Bcl-­‐2 family proteins MOMP Cyt C APAF-­‐1 Caspases
Signaling complex
Cellular stress Hypoxia DNA damage Cell demoliCon zymogens
Substrate deprivaCon Cleavage of DNA, cellular proteins Phagocytosis RegulaCon of apoptosis BH3-­‐
mimeCc BH3-­‐only proteins More potent killers Pro-­‐
survival proteins BH3-­‐only proteins More restricted killers Cragg et al, Nat Rev Can 2009 20 11/11/11 Bcl-­‐2 (B-­‐cell Lymphoma-­‐2) Family Pro-­‐
apoptoCc (BH3-­‐only) Pro-­‐survival Bad
Bcl-­‐2
Bim
Bcl-­‐xL
Pro-­‐apoptoCc (mulC-­‐domain) Puma
Noxa
Bcl-­‐w
Mcl-­‐1
A1
Bax/Bak Bax and Bak are restrained in healthy cells Pro-­‐
apoptoCc (BH3-­‐only) Pro-­‐survival Pro-­‐apoptoCc (mulC-­‐domain) Bad
Bcl-­‐2
Bim
Bcl-­‐xL
Puma
Bcl-­‐w
Noxa
Mcl-­‐1
A1
Bax/Bak 21 11/11/11 BH3-­‐only proteins are acCvated by discrete cues Cytokine withdrawal Pro-­‐
apoptoCc (BH3-­‐only) Pro-­‐survival Steroid
p53
Bad
Bim
Bcl-­‐2
DNA damage hypoxia
Ca2+ flux, Taxol, UV
Pro-­‐apoptoCc (mulC-­‐domain) Puma
Bcl-­‐xL
Noxa
Bcl-­‐w
Mcl-­‐1
A1
Bax/Bak NeutralisaCon of anC-­‐apoptoCc proteins releases Bax/Bak Cytokine withdrawal Pro-­‐
apoptoCc (BH3-­‐only) Pro-­‐survival Pro-­‐apoptoCc (mulC-­‐domain) Steroid
p53
Bad
Bcl-­‐2
DNA damage hypoxia
Ca2+ flux, Taxol, UV
Bim
Bcl-­‐xL
Puma
Bcl-­‐w
Noxa
Mcl-­‐1
A1
Bax/Bak Apoptosis 22 11/11/11 Tumour cells acquire lesions at mulCple levels Cytokine withdrawal Pro-­‐
apoptoCc (BH3-­‐only) Pro-­‐survival Steroid
p53
Bad
Bim
Bcl-­‐2
DNA damage hypoxia
Ca2+ flux, Taxol, UV
Pro-­‐apoptoCc (mulC-­‐domain) Puma
Bcl-­‐xL
Noxa
Bcl-­‐w
Mcl-­‐1
A1
Bax/Bak TargeCng prosurvival proteins to overcome chemoresistance Cytokine withdrawal Pro-­‐
apoptoCc (BH3-­‐only) Pro-­‐survival Pro-­‐apoptoCc (mulC-­‐domain) DNA damage hypoxia
Ca2+ flux, Taxol, UV
Steroid
p53
Bad
Bim
Puma
Bcl-­‐w Noxa
Drug
Bcl-­‐2
Bcl-­‐xL
Mcl-­‐1
A1
Bax/Bak Apoptosis 23 11/11/11 Expression of pro-­‐survival proteins in breast cancer •  HER2+ BC is correlated with high levels of Mcl-­‐1 !  Mcl-­‐1 is downstream target of acCvated EGFR and PI3K signaling !  HercepCn sensiCzes cells to apoptosis by reducing Mcl-­‐1 expression !  Mcl-­‐1 overexpression confers resistance to drug induced apoptosis •  Estradiol induces !  Bcl-­‐2 (pro-­‐survival) expression in MCF7 cells via 2 EREs located with its coding region (Perillo, MCB 00) !  Puma (pro-­‐apoptoCc) downregulaCon in ER+ cell lines (Bur, Onc 11) Establishment of orthotopic breast cancer xenograZs Bcl-­‐2 IHC TNBC TNBC HER2+ 24 11/11/11 CombinaCon therapy results in tumor response and increased survival in triple negaCve xenograZs High Bcl-­‐2 Mid Mcl-­‐1 Low Puma High Noxa High Bcl-­‐2 Mid Mcl-­‐1 Mid Puma Mid Noxa High Bcl-­‐2 Mid Mcl-­‐1 High Puma Low Noxa Oakes et al, PNAS 2011 CombinaCon therapy has no effect on tumor xenograZs with low BCL-­‐2 25 11/11/11 Pathways in Tumor IniCaCng Cells Epithelial Mesenchymal TransiCon Mammary development meets cancer genomics Old paradigm New model Basal-­‐like Claudin-­‐low BRCA1 Normal-­‐like Gene signature Others? HER2 Luminal B Basal-­‐like Luminal A (BRCA1) HER2 Luminal B Luminal A Lim E et al. Nature Med 2009 26 11/11/11 Models of heterogeneity in solid cancers Clonal selec.on model CSC model Reya et al. Nature 2001 Breast cancer tumor iniCaCng cells Minimum no of cells to produce cancer >100,000 200 Al-­‐Hajj et al. PNAS 2003 27 11/11/11 ImplicaCons of the cancer stem cell hypothesis on cancer therapy Cure Clinical recurrence Failure of primary therapy CSC targeCng strategies DifferenCaCon therapy (APML) Reya et al. Nature 2001 Wnt/β-­‐Catenin Signalling Pathway IncassaC et al. Breast Cancer Research 2010 28 11/11/11 Paracrine sCmulaCon of Wnt/β-­‐Catenin Pathway in stem cells EMT and Tumor iniCaCng cell phenotype •  EMT is a process by which cells acquire molecular alteraCons that facilitate dysfuncConal cell–cell adhesive interacCons and juncCons, as well as a more spindle-­‐shaped morphology. •  Claudin-­‐low subtype is characterized by high expression of EMT markers •  EMT promotes cancer cell progression and invasion into the surrounding microenvironment, and •  EMT promotes the expression of stem cell and TIC markers, and promotes self-­‐renewal capability. •  Developmental signaling pathways that play a role in mammary carcinogenesis and stem cell biology include Notch, PI3-­‐AKT, Wnt, Hedgehog and p53. 29 11/11/11 Epithelial-­‐Mesenchymal transiCon Foubert et al. Breast Cancer Research 2010 Pathways & inhibitors in TICs and EMT Stem cells and TICs •  Notch •  Wnt/β-­‐Catenin γ Secretase inhibtors Wnt inhibitors EMT •  TGF-­‐β •  Snail, Slug and Twist 30 11/11/11 QuesCons 31