Comprehensive anti-tumor effect of Brusatol through inhibition of cell viability and promotion of apoptosis caused by autophagy via the PI3K/Akt/mTOR pathway in hepatocellular carcinoma

Brusatol, a natural quassinoid isolated from a traditional Chinese herbal medicine known as Bruceae Fructus, has recently been reported to possess powerful cytotoxic effects against various cancer cell lines, highlighting its potential as an anti-cancer drug. However, the precise molecular mechanisms by which Brusatol exerts its anti-cancer effects remain poorly understood in hepatocellular carcinoma (HCC). In this study, we demonstrated that Brusatol inhibited cell viability, proliferation and induced apoptosis in liver cancer lines. Furthermore, Brusatol could activate autophagy in diverse liver cell lines, and the autophagy inhibitor chloroquine (CQ) reversed Brusatol-induced apoptosis in Bel7404 cells. In addition, we found that Brusatol inhibited PI3K/Akt/mTOR. Brusatol may also inhibit invasion, migration and the epithelial-mesenchymal transition (EMT). In a human liver xenograft tumor model in nude mice, immunohistochemistry showed that Brusatol significantly inhibited tumor invasion and proliferation. Taken together, these results revealed that Brusatol effectively inhibited proliferation and induced apoptosis in HCC through autophagy induction, probably via the PI3K/Akt/mTOR pathway, and inhibited tumor invasion and migration in vivo and in vitro. All above indicated that Brusatol is an encouraging anti-tumor drug candidate or a supplement to the current chemotherapeutic systematic plan.