Objective: The study was undertaken to investigate the effects of polyethyleneimine (PEI)-mediated adenovirus 5 early region 1A (E1A) on radiosensitivity of human hepatic carcinoma cell in vitro and to disclosure the underlying mechanism.
Materials and methods: Human hepatic carcinoma SMMC-7721 cell line was transfected with E1A gene using PEI vector. Untransfected cells (SMMC-7721 group), cells transfected with blank-vector (SMMC-7721-vect group), and cells transfected with E1A gene (SMMC-7721-E1A group) were treated with 6 MV X-ray irradiation at doses of 0, 1, 2, 4, 8 and Gy, respectively. Radiosensitivity was determined by MTT assay and quantified by calculating the cell survival rate. Cell-cycle distribution and apotosis rate were monitored by flow cytometry.
Results: The survival rate of SMMC-7721-E1A was significantly lower than that of SMMC-7721 cell. Apoptosis rate of SMMC-7721-E1A group was significantly higher than that of SMMC-7721group (P<0.01).The ratio of S stage in cell cycle of SMMC-7721-E1A was significantly lower than that in SMMC-7721 cell. The ratio of G2/M stage in cell cycle of SMMC-7721-E1A was significantly higher than that in SMMC-7721 cell (P<0.01).
Conclusion: PEI could transfect E1A gene into hepatic carcinoma cells PEI-mediated E1A could effectively enhance radiosensitivity of hepatic carcinoma cells which may be related to its effects on apoptosis promoting leading to S phase suppression and G2/M phase arrest.<br />.
Keywords: Human hepatic carcinoma cell; adenovirus 5 early region 1A; polyethyleneimine; radio-sensitivity.