High-efficiency transfer and expression of AdCMV-p53 in human hepatocellular carcinoma cells induced by low-dose carbon-ion radiation

Objective To investigate whether the irradiation with C-beam could enhance adenovirus-mediated transfer and expression of p53 in human hepatocellular carcinoma. Materials and methods HepG2 cells were exposed to C-beam or gamma-ray and then infected with replicationdeficient adenovirus recombinant vectors containing human wild-type p53 or green fluorescent protein, respectively. The transfer efficiency and expression level of the exogenous gene were detected by flow cytometric analysis. Cell survival fraction was detected by clonogenic assay. Results The transfer frequency in C-beam or gamma-irradiated groups increased by 50-83% and 5.7-38.0% compared with the control, respectively (P < 0.05). Compared with C-beam alone, p53 alone, and gamma-ray with p53, the percentages of p53 positive cells for 1 Gy C-beam with p53 increased by 56.0-72.0%, 63.5-82.0%, and 31.3-72.5% on first and third day after the treatments, respectively (P < 0.05). The survival fractions for the 2Gy C-bearn and AdCMV-p53 infection groups decreased to similar to 2%. Conclusion C-beam irradiation could significantly promote AdCMV-green fluorescent protein transfer and expression of p53.