Sinularin Exerts Anti-cancer Effects by Inducing Oxidative Stress-mediated Ferroptosis, Apoptosis, and Autophagy in Prostate Cancer Cells

Prostate cancer is the second-leading cause of cancer death in men. Sinularin is a soft coralsderived natural compound that has anticancer activity in many cancer cells. However, the pharmacological action of sinularin in prostate cancer is unclear.The aim of the study is to examine the anticancer effects of sinularin in prostate cancer cells.We explored the anticancer effects of sinularin on the prostate cancer cell lines, PC3, DU145, and LNCaP, by MTT, Transwell assay, wound healing, flow cytometry, and western blotting.Sinularin inhibited the cell viability and colony formation of these cancer cells. Furthermore, sinularin inhibited testosterone-induced cell growth in LNCaP cells by downregulating the protein expression levels of androgen receptor (AR), type Ⅱ 5α-reductase, and prostate-specific antigen (PSA). Sinularin significantly attenuated the invasion and migration ability of PC3 and DU145 cells, with or without TGF-β1 treatment. Sinularin inhibited epithelialmesenchymal transition (EMT) in DU145 cells after 48 h of treatment by regulating the protein expression levels of Ecadherin, N-cadherin, and vimentin. Sinularin induced apoptosis, autophagy, and ferroptosis by regulating the protein expression levels of Beclin-1, LC3B, NRF2, GPX4, PARP, caspase-3, caspase-7, caspase-9, cleaved-PARP, Bcl-2, and Bax. Moreover, intracellular reactive oxygen species (ROS) were increased but glutathione was decreased after sinularin treatment in PC3, DU145 and LNCaP cells.Sinularin regulated the androgen receptor signaling pathway and triggered apoptosis, autophagy, and ferroptosis in prostate cancer cells. In conclusion, the results indicated that sinularin may be a candidate agent for human prostate cancer and need further study for being applied to human.