Abstract POSTER-THER-1427: Epidermal growth factor receptor mediated alterations in DNA methylation associated with the development of platinum resistance in ovarian cancer cells

Abstract

Abstract Acquisition of platinum resistance following first line platinum-taxane therapy occurs in a large portion of ovarian cancer patients and continues to be a major challenge in clinical effectiveness. To date, there are limited interventions available to prevent or reverse platinum resistance; however, there has been some advances in the use of demethylating agents in the resensitization of patients to platinum based therapy. This highlights epigenetic alterations, in particular DNA methylation, as critical contributors to the acquisition of drug resistance in ovarian cancer. The Epidermal Growth Factor Receptor (EGFR) has also been linked to chemoresistance and is known to be activated by cisplatin treatment. We previously published that activation of the EGFR can increase DNA methyltransferase (DMNT) activity and, over extended activation, can significantly increase global DNA methylation in ovarian cancer cells. We hypothesized that cisplatin induced activation of the EGFR could mediate changes in DNA methylation associated with the development of platinum resistance. To investigate this, we used an in vitro model of platinum resistance and evaluated EGFR signaling and DNMT activity after acute cisplatin and in platinum resistant cells. We found that cisplatin treatment activates the EGFR and downstream signaling pathways JAK and AKT. Cisplatin also increased DNMT activity and this increase was dependent on EGFR activation. Over repeated sequential treatments of cisplatin, we successfully developed platinum resistant cells that possessed significant increases in DNMT activity and had moderate, but significant, increases in global DNA methylation. Preliminary data using the EGFR inhibitor Erlotinib during the development of platinum resistant cells suggest that the EGFR plays an integral role in the acquisition of platinum resistance. This work implicates EGFR driven alterations to DNMT activity and DNA methylation as a novel mechanism for development of platinum resistance. Further studies are currently being done to evaluate potential alterations in activation of downstream signaling pathways, levels of DNA methyltransferases and other changes in expression associated with platinum resistance. Citation Format: Sabrina L. Samudio-Ruiz, Michaela L. Granados, Laurie G. Hudson. Epidermal growth factor receptor mediated alterations in DNA methylation associated with the development of platinum resistance in ovarian cancer cells [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1427.