Inhibiting EMT, sternness and cell cycle involved in baicalin-induced growth inhibition and apoptosis in colorectal cancer cells

Although baicalin, a flavonoid derived from Scutellaria baicalensis Georgi, has been reported to have anti-tumor activity in various cancers, the molecular mechanism remains imperfect. Here, we show that baicalin inhibits cell growth, migration and invasion and induces cell apoptosis by inhibiting cell cycle, viability, the epithelial-mesenchymal transition (EMT) and cellular stemness in colorectal cancer (CRC) cells. In detail, baicalin treatment in CRC cells induces cell cycle arrest in G1 phase and promotes p53-independent cell apoptosis, inhibits both endogenous and exogenous TGF beta 1-induced EMT of colorectal cancer cells by inhibiting TGF beta/Smad pathway. Cell sphere-formation experiments show that baicalin has a strong inhibitory efficacy on the stemness of CRC cells by decreasing the marker proteins of cancer stem cell (CSC) and inhibits the formation of CSC-like cell spheres in CRC cells. In vivo experiments also identify that baicalin has an anti-tumor effect by down-regulating the levels of marker proteins of cell cycle, EMT and stemness in the orthotopic transplantation tumors of CRC cells in BALB/c nude mice. Collectively, our in vitro and in vivo results indicate that multiple inhibition of cell cycle, EMT and stemness is the real molecular mechanism of baicalin in effectively inducing cell growth inhibition and apoptosis in CRC cells.