Radix Angelicae Sinensis and Radix Hedysari enhance radiosensitivity of 12C6+ radiation in human liver cancer cells by modulating apoptosis protein.

OBJECTIVES To investigate the radiosensitizing effects of Radix Angelicae Sinensis-Radix Hedysari (RAS-RH [an ultra-filtration extract]) and its underlying mechanisms in human liver cancer cells H22. METHODS This study was conducted between September 2010 and August 2012 in the Gansu University of Traditional Chinese Medicine, Lanzhou, China. The groups were assigned as the control group, drug (RAS-RH) group, 12C6+ radiation group, and combination group. The cell counting kit-8 assay, colony formation assay, cell cycle changes, and apoptosis analysis were carried out, and survivin and casepase-9 were evaluated by reverse transcription polymerase chain reaction and Western blot analyses in the 4 groups. RESULTS The inhibitory effect of RAS-RH on H22 cells was dependent on both concentration and time, RAS-RH was able to enhance the radiosensitivity of H22 cells by increasing cell survival fraction and radiosensitization parameters. Apoptosis and the gap2/mitosis (G2/M) phase transition induced by 12C6+ heavy ion radiation was enhanced by RAS-RH treatment. Irradiation, combined with RAS-RH, decreased survivin expression while increasing casepase-9 expression in H22 cells. CONCLUSION The RAS-RH increased the radiosensitivity of H22 cells of 12C6+ heavy ion radiation significantly, and its possible mechanism of radiosensitization is to enhance caspase-dependent apoptosis through the down-regulation of survivin, thus, it can be used as an effective radiosensitizer.