Translational studies within the TAMRAD randomized GINECO trial: evidence for mTORC1 activation marker as a predictive factor for everolimus efficacy in advanced breast cancer.

BACKGROUND Everolimus is an agent frequently associated with specific toxicities. Predictive markers of efficacy are needed to help define which patients could benefit from it. The goal of this exploratory study was to identify potential predictive biomarkers in the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) activation pathway using primary tumor samples collected during the phase II tamoxifen plus everolimus (TAMRAD) trial. PATIENTS AND METHODS Tumor tissues were collected retrospectively from the TAMRAD trial. Immunohistochemistry was carried out using specific antibodies directed toward proteins that result in mTORC1 activation [canonical phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mTOR or alternative pathways]. DNA was extracted from the tumor tissue; mutation screening in the PIK3CA gene (exons 9 and 20) and the KRAS gene (exons 2 and 3) was first carried out using Sanger direct sequencing, and then completed by next-generation sequencing for PIK3CA. An exploratory analysis of everolimus efficacy in terms of a time-to-progression (TTP) increase was carried out in each biomarker subgroup (high versus low expression referring to the median percentage of marked cells). RESULTS A total of 55 primary tumor samples from the TAMRAD trial—25 from the tamoxifen-alone group and 30 from the tamoxifen/everolimus group—were evaluated for biomarkers. The subgroups most likely to have an improvement in TTP with tamoxifen/everolimus therapy, compared with tamoxifen alone, were patients with high p4EBP1, low 4EBP1, low liver kinase B1, low pAkt, and low PI3K. Among the 45 samples screened for mutation status, nine samples (20%; 95% CI 9.6-34.6) had a PIK3CA mutation. KRAS mutation was observed in one patient. CONCLUSIONS A positive correlation between late effectors of mTORC1 activation, a positive correlation between Akt-independent mTORC1 activation, and an inverse correlation between canonical PI3K/Akt/mTOR pathway and everolimus efficacy were observed in this exploratory analysis. However, these correlations need to be validated in larger studies before applying the findings to routine clinical practice.

[1]  S. Mader,et al.  LKB1 when associated with methylatedERα is a marker of bad prognosis in breast cancer , 2014, International journal of cancer.

[2]  C. Lefebvre,et al.  Abstract S6-07: Genomic characterisation of metastatic samples from breast cancer patients using next generation sequencing , 2013 .

[3]  T. Petit,et al.  Predicting everolimus treatment efficacy in patients with advanced endometrial carcinoma: a GINECO group study , 2013, Targeted Oncology.

[4]  I. Treilleux,et al.  Molecular characterization of anastrozole resistance in breast cancer: Pivotal role of the Akt/mTOR pathway in the emergence of de novo or acquired resistance and importance of combining the allosteric Akt inhibitor MK‐2206 with an aromatase inhibitor , 2013, International journal of cancer.

[5]  I. Treilleux,et al.  Activation of rapid oestrogen signalling in aggressive human breast cancers , 2012, EMBO molecular medicine.

[6]  I. Ray-Coquard,et al.  Randomized phase II trial of everolimus in combination with tamoxifen in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer with prior exposure to aromatase inhibitors: a GINECO study. , 2012, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[7]  Steven J. M. Jones,et al.  Comprehensive molecular portraits of human breast tumors , 2012, Nature.

[8]  R. Kurzrock,et al.  PI3K/AKT/mTOR inhibitors in patients with breast and gynecologic malignancies harboring PIK3CA mutations. , 2012, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[9]  M. Piccart,et al.  Everolimus in postmenopausal hormone-receptor-positive advanced breast cancer. , 2012, The New England journal of medicine.

[10]  R. Naumann.  The role of the phosphatidylinositol 3-kinase (PI3K) pathway in the development and treatment of uterine cancer. , 2011, Gynecologic oncology.

[11]  Sean E. Egan,et al.  Elevated PI3K signaling drives multiple Breast Cancer subtypes , 2011, Oncotarget.

[12]  B. Hennessy,et al.  Next-generation mTOR inhibitors in clinical oncology: how pathway complexity informs therapeutic strategy. , 2011, The Journal of clinical investigation.

[13]  G. Mills,et al.  Hyperactivation of phosphatidylinositol-3 kinase promotes escape from hormone dependence in estrogen receptor-positive human breast cancer. , 2010, The Journal of clinical investigation.

[14]  Paul Ellis,et al.  PIK3CA mutations associated with gene signature of low mTORC1 signaling and better outcomes in estrogen receptor–positive breast cancer , 2010, Proceedings of the National Academy of Sciences.

[15]  T. O'reilly,et al.  Biomarker Development for the Clinical Activity of the mTOR Inhibitor Everolimus (RAD001): Processes, Limitations, and Further Proposals. , 2010, Translational oncology.

[16]  Robert L. Sutherland,et al.  Biological determinants of endocrine resistance in breast cancer , 2009, Nature Reviews Cancer.

[17]  W. Gerald,et al.  PIK3CA Mutation Associates with Improved Outcome in Breast Cancer , 2009, Clinical Cancer Research.

[18]  Jeffrey A. Engelman,et al.  Targeting PI3K signalling in cancer: opportunities, challenges and limitations , 2009, Nature Reviews Cancer.

[19]  R. Memmott,et al.  Akt-dependent and -independent mechanisms of mTOR regulation in cancer. , 2009, Cellular signalling.

[20]  P. Pandolfi,et al.  Inhibition of mTORC1 leads to MAPK pathway activation through a PI3K-dependent feedback loop in human cancer. , 2008, The Journal of clinical investigation.

[21]  M. Sanchez-Cespedes.  A role for LKB1 gene in human cancer beyond the Peutz–Jeghers syndrome , 2007, Oncogene.

[22]  A. Marchetti,et al.  Different Prognostic Roles of Mutations in the Helical and Kinase Domains of the PIK3CA Gene in Breast Carcinomas , 2007, Clinical Cancer Research.

[23]  M. Hall,et al.  TOR Signaling in Growth and Metabolism , 2006, Cell.

[24]  Paul Tempst,et al.  Phosphorylation and Functional Inactivation of TSC2 by Erk Implications for Tuberous Sclerosisand Cancer Pathogenesis , 2005, Cell.

[25]  Hanina Hibshoosh,et al.  PIK3CA mutations correlate with hormone receptors, node metastasis, and ERBB2, and are mutually exclusive with PTEN loss in human breast carcinoma. , 2005, Cancer research.

[26]  K. Inoki,et al.  TSC2 Mediates Cellular Energy Response to Control Cell Growth and Survival , 2003, Cell.

[27]  K. Inoki,et al.  TSC2 is phosphorylated and inhibited by Akt and suppresses mTOR signalling , 2002, Nature Cell Biology.

[28]  M. Guo,et al.  The effect of prolonged cold ischemia time on estrogen receptor immunohistochemistry in breast cancer , 2013, Modern Pathology.

[29]  L. Liotta,et al.  Phosphoprotein stability in clinical tissue and its relevance for reverse phase protein microarray technology. , 2011, Methods in molecular biology.

[30]  J. Olson,et al.  Phosphatidyl-inositol-3-kinase alpha catalytic subunit mutation and response to neoadjuvant endocrine therapy for estrogen receptor positive breast cancer , 2009, Breast Cancer Research and Treatment.