Abstract 4498: Afatinib, an irreversible ErbB family inhibitor, demonstrates activity against HER2 mutated cervical cancer in vitro

Abstract

Abstract Uterine cervical cancer (UCC) is the second leading cause of cancer deaths among women worldwide and results in 275,000 deaths annually. Functional characterization of cancer-associated genetic alterations may lead to new therapeutic approaches using molecularly targeted therapies which have the potential to improve patient outcomes. Consistent with this view, whole exome sequencing studies in a variety of human tumors including cervical cancer have recently identified somatic mutations in genes that encode for the ErbB family receptors. Importantly, some of these mutations have been shown to be “drivers” and to correlate with tumor sensitivity to the exposure to ErbB tyrosine kinase inhibitors in vitro as well as in vivo. In this study we have evaluated whether genetic alterations in the c-erbB2 gene determine the sensitivity of UCC primary cell lines to Afatinib, an EGFR, HER2, and HER4 irreversible tyrosine kinase inhibitor. Ten primary UCC cell lines, (two harboring c-erbB2 gene mutations in the extracellular HER2/neu domain [i.e., the S280F and E375D mutations-ref genome hg18] and eight harboring wild type c-erbB2), established as long term cultures in vitro, were analyzed in our study. The effect of Afatinib on cell growth, cell-cycle distribution and signaling were assessed using flow cytometry and western blot analysis following incubation of primary UCC cell lines with scalar concentrations of Afatinib for 72 hours in vitro. We found that despite similar ErbB2 mRNA expression levels by qRT-PCR in the mutated versus the wild type c-erbB2 groups, IC50 values in response to Afatinib were significantly lower in the group of mutated cell lines than in the non-mutated control UCC (MEAN±SEM = 0.55±0.11 vs. 1.64±0.09 μM, P<0.05). Furthermore, Afatinib growth-inhibition was associated with a significant and dose-dependent increase in the percentage of cells blocked in the G1 cell cycle phase as well as a dose-dependent dephosphorylation of HER2, S6, AKT and ERK in both c-erbB2 mutated and wild type UCC cell lines. Our data suggests that Afatinib, a recently FDA approved drug, is highly effective against c-erbB2 mutated UCC in vitro and could represent a valid therapeutic option for patients harboring c-erbB2 mutated advanced/recurrent cervical cancers unresponsive to radiation and/or chemotherapy. Citation Format: Salvatore Lopez, Emiliano Cocco, Bellone Stefania, Ileana Bortolomai, Elena Bonazzoli, Roberta Nicoletti, Carlton Schwab, Diana P. English, Corrado Terranova, Roberto Angioli, Alessandro D. Santin. Afatinib, an irreversible ErbB family inhibitor, demonstrates activity against HER2 mutated cervical cancer in vitro. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4498. doi:10.1158/1538-7445.AM2014-4498