Radiosensitization by inhibiting survivin in human hepatoma HepG2 cells to high-LET radiation

In this study,whether survivin plays a direct role in mediating high-let radiation resistance in human hepatoma cells was investigated. small interfering rna (sirna) targeting survivin mrna was designed and transfected into human hepatoma hepg2 cells. real-time pcr and western blotting analyses revealed that survivin expression in hepg2 cells decreased at both transcriptional and post-transcriptional levels after treatment with survivin-specific sirna. caspase-3 activity was determined with a microplate reader assay as well. following exposure to high-let carbon ions,a reduced clonogenic survival effect,increased apoptotic rates and caspase-3 activity were observed in the cells treated with the sirna compared to those untreated with the sirna. the cells with transfection of the survivin-specific sirna also increased the level of g 2/m arrest. these results suggest that survivin definitely plays a role in mediating the resistance of hepg2 cells to high-let radiation and depressing survivin expression might be useful to improve the therapeutic efficacy of heavy ions for radioresistant solid tumors.