Abstract 4769: Gene expression profiling of response to short- and long-term treatment of LSZ102 in MCF7 cells

Abstract

Abstract Breast cancer is the most common cancer in women worldwide, and the second most common cause of cancer death in woman in the US. Close to 80% of breast cancer are estrogen receptor (ER) positive and can benefit from antiestrogen treatment. LSZ102 is a novel oral selective estrogen receptor degrader (SERD) in clinical development, which exhibits potent activity in inducing ER degradation, modulating ER-target genes transcription and inhibits the proliferation of breast cancer cells both in-vitro and in-vivo. In this study, we have investigated the effects of short term and prolonged LSZ102 treatment on global gene expression in ER positive MCF-7 breast cancer cells. MCF-7 cells were treated with LSZ102 for 24 hours, 8 weeks and 14 weeks, followed by transcriptome profiling by RNA sequencing. Our findings show LSZ102 effectively inhibited ER transcriptional activity and lead to a sustained suppression of estrogen responsive genes expression in LSZ102-treated cells of all time points. We also observed a cumulative up-regulation of EPAS1, a hypoxia-inducible transcription factor. In addition, we found up-regulation of EGFR and ERBB2 genes and regulated genes in cells with prolonged treatment of LSZ102. In summary, our results suggest a possible role of EPAS1 in eliciting a compensatory growth promoting signals in breast cancer cells adapted to ER inhibition. Citation Format: Choi Lai Tiong Yip, Joshua Korn, David Ruddy, Daniel Rakiec, Darrin Stuart, Alex Gaither. Gene expression profiling of response to short- and long-term treatment of LSZ102 in MCF7 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4769.