DSGOST regulates resistance via activation of autophagy in gastric cancer.

Danggui-Sayuk-Ga-Osuyu-Saenggang-Tang (DSGOST in Korean, Danggui-Sini-Jia-Wuzhuyu-Shengian-Tang in Chinese, and Tokishigyakukagoshuyushokyoto (TJ-38) in Japanese), a well-known traditional Korean/Chinese/Japanese medicine, has long been used to treat vascular diseases such as Raynaud's phenomenon (RP). However, anticancer effect of DSGOST remains elusive. In this study, we checked if DSGOST has an anticancer effect against gastric cancer cells, and investigated the mechanisms underlying DSGOST resistance. Moreover, DSGOST regulates chemoresistance in cisplatin-treated gastric cancer cells. Interestingly, DSGOST treatment induced the accumulation of GFP-LC3 puncta and increased the level of autophagy markers, such as LC3-II, ATG5, and Beclin-1, indicating activated autophagy. Furthermore, DSGOST could activate epithelial-to-mesenchymal transition (EMT) and exosomes via induction of autophagy. DSGOST in combination with TGFβ also induced autophagy and EMT. However, autophagy inhibition induces DSGOST-mediated cell death in gastric cancer cells. In addition, autophagy inhibition blocks the activation of DSGOST-mediated EMT markers including N-cadherin, Snail, Slug, vimentin, β-catenin, p-Smad2, and p-Smad3. Taken together, these findings indicated that prosurvival autophagy was one of the mechanisms involved in the resistance of gastric cancer to DSGOST. Targeting the inhibition of autophagy could be an effective therapeutic approach to overcome resistance to DSGOST in gastric cancer.