Tetrandrine Enhances Radiosensitization in Human Hepatocellular Carcinoma Cell Lines

The goal of this study was to determine whether tetrandrine enhanced radiosensitization in different hepatocellular carcinoma cell lines and to elucidate the potential mechanism. We also tested whether PA28γ was regulated by tetrandrine. The human hepatocellular carcinoma cell lines HepG2 and LM3 were divided into six groups: control; low-dosage (0.5 or 5 μg/ml) tetrandrine alone; high-dosage (1.0 or 10 μg/ml) tetrandrine alone; irradiation alone; irradiation with low-dosage (0.5 μg/ml or 5 μg/ml) tetrandrine; and irradiation with high-dosage (1.0 μg/ml or 10 μg/ml) tetrandrine. Colony-forming assays were performed. Expression of cyclin and apoptosis-related proteins, including cyclin B1, phosphorylated cyclin-dependent kinase 1 [phospho-CDC2 (Tyr15)], Bax and caspase-3, as well as PA28γ expression, were evaluated using Western blot analysis. Apoptosis rate and cell cycle distribution were examined using flow cytometry analysis. Tetrandrine enhanced radiosensitivity in HepG2 and LM3 cells, as characterize...