A flavone, Wogonin from Scutellaria baicalensis inhibits the proliferation of human colorectal cancer cells by inducing of autophagy, apoptosis and G2/M cell cycle arrest via modulating the PI3K/AKT and STAT3 signalling pathways.

Abstract

PURPOSE: The purpose of this study was to examine the anticancer effects of a flavone from Scutellaria baicalensis wogonin against a panel of colorectal cancer cells. METHODS: The SW1417, SW48, DLD-1, HCT-15, LS-180 and CCD-18Co cell lines were used for the evaluation of the anticancer effects of wogonin. WST-1 and colony formation assays were used for cell viability assessment. Cell cycle analysis was assessed by flow cytometry. Autophagy was detected by electron microscopy. Apoptosis was detected by acridine orange (AO)/ethidium bromide (EB) staining. Cell protein expression was checked by western blotting. RESULTS: The cytotoxic effects of wogonin were comparatively negligible against the normal CCD-18Co cells with an IC50 of >100 µM. Investigation of the mechanism of action revealed that wogonin exerts growth inhibitory effects on the SW48 colorectal cancer cells by autophagic and apoptotic cell death. This was also accompanied with upregulation of autophagic proteins such as LC3II and Beclin 1 as well as the apoptotic proteins such as caspase 3, 8 and 9 and Bax expressions. Wogonin also induced arrest of the SW48 cells at the G2/M check point of the cell cycle. In addition, wogonin could also inhibit the PI3K/AKT and STAT3 signal transduction pathways. CONCLUSION: These results suggest that wogonin exerts potent anticancer effects on colorectal cancer cells and may prove essential in the management of colorectal cancer.