Abstract 3512: Cyclopamine enhances TRAIL-induced apoptosis by induction of DR5 via ER stress in gastric cancer cells

Abstract

Abstract Activation of sonic hedgehog (Shh) signaling has been involved in progression of various cancers. Cyclopamine uses as effective treatment for cancers in which hedgehog signaling is overexpressed. In this study, we elucidated that cyclopamine sensitizes to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in gastric cancer cells. Single treatment with cyclopamine or TRAIL could not induce significant cytotoxicity in gastric cancer cells. However, combination treatment of TRAIL with cyclopamine effectively led to caspase dependent apoptosis. We found that cyclopamine increased ER (Endoplasmic Reticulum) stress level in gastric cancer cells, and using ER stress inhibitor attenuated the cell death by cyclopamine. As further underlying mechanism, induction of ER stress by cyclopamine caused upregulation of JNK (c-Jun N-terminal kinases) protein, and then accumulation of p53 protein. We conducted experiment using p53 wild-type and p53-mutated gastric cancer cells, and this of particular importance since p53 wild-type gastric cancer cells had more significant efficacy than p53-mutated cells by cyclopamine. Accumulation of p53 increased DR5 protein. Taken together, we showed that cyclopamine sensitizes to TRAIL-induced apoptosis in gastric cancer cells. Citation Format: Yoo Jin Na, Dae-Hee Lee, Jung Lim Kim, Bo Ram Kim, Seong Hye Park, Byung-Wook Min, Sun Il Lee, SangHee Kang, Sung Yup Joung, Suk Young Lee, Hong-Jun Kim, Sang Cheul Oh. Cyclopamine enhances TRAIL-induced apoptosis by induction of DR5 via ER stress in gastric cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3512.