Abstract 2641: Transactivation of EGFR and mTOR pathway by H2Sin cancer cells

Abstract

Abstract Hydrogen sulfide regulates a variety of physiological and pathological processes. Previous studies have suggested that H2S plays a significant role as a secondary messenger in cellular signaling. Interestingly, it has been found that this unique gaseous molecule, or gasotransmitter, is capable of producing both pro- and anti- apoptotic activity in cultured cells. It has been speculated that these gasotransmitters are endogenously generated in mammalian systems through enzymatic catalysis. Our pursuits focus on comparing the effects of H2S on various lines of cancer cells (CaOV3-ovarian cancer cells, A375-melanoma cells, HeLa-cervical cancer cells, and WM 266-4-melanoma cells). Using a water-soluble, slow-releasing H2S donor, GYY4137 (200 μM), we studied how both concentration and time affect cell viability and investigated further whether H2S causes pro- or anti- apoptotic activity. Existing data have indicated that GYY4137 may activate molecular targets, including EGFR, ERK and JNK. We hypothesize that GYY4137 activates mTOR (mammalian target of rapamycin) with result of phosphorylation of S6, leading to either cell death or cell proliferation. By monitoring various proteins through Western blot analysis and confocal microscopy we studied the activation of EGFR/mTOR pathway in response to GYY4137 treatment. Our data showed that the longer the treatment the more prevalent phosphor S6 and phosphor-EGFR are. Noticeably, we observed a significant difference between 15 minutes and 30 minutes, suggesting that GYY4137 has the largest effect after 30 minutes of treatment. We further studied cell growth and viability using MTT assay to investigate the effects of various concentrations of GYY4137 on the cells. Our data indicated that the stronger the concentration is, the lower the cell viability. Similarly, we used Mitotracker ® Red dye to stain for mitochondrial activity in CaOV3 and WM 266-4 cells treated at various time points. Overall, mitochondrial activity increased when cells were exposed to GYY4137, suggesting that H2S may cause anti-apoptotic activity, and instead favor cell growth at the concentration we used. Collectively, our data suggests that the H2S donor, GYY4137 has a significant effect on cell proliferation and survival in several cancerous cells likely mediated by transactivation of EGFR and mTOR pathways. Note: This abstract was not presented at the meeting. Citation Format: Jillian L. Higgins, Aileen K. Kraus, Dominic T. Arruda, Hao Guo, Mattew Lautato, Christopher Lautato, Eliana DaCunha, Ashley Chen, Ricky Yao, Dongqin Yang, Yinsheng Wan. Transactivation of EGFR and mTOR pathway by H2Sin cancer 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 2641.