Effect of insulin-like growth factor-I receptor on radiosensitivity of HepG2 cells

Abstract

Objective To explore the effect of insulin-like growth factor-Ⅰ (IGF-Ⅰ) receptor on radiosensitivity of HepG2 cells and the underlying mechanism. Methods HepG2 cells were divided into the following groups: negative control group, siRNA group, irradiation group and combined group. HepG2 cells were transfected with IGF-Ⅰ receptor siRNA combined with irradiation therapy to investigate the effect on cell proliferation by methyl thiazolyl tetrazolium and cell cycle using flow cytometry. Expression of IGF-Ⅰ receptor, proliferating cell nuclear antigen (PCNA), cyclin-dependent kinases 1(CDK1) and Survivin were detected using Western blotting and Q-PCR. Results The expression of IGF-Ⅰ receptor in HepG2 cells was decreased significantly after siRNA transfection compared with the control group. After the combinational therapy, cell viability was decreased significantly according with control group [(1.02±0.08) vs. (1.08± 0.10) vs. (0.60±0.07)]; In addition, cell cycle was arrested in G2/M[(20.3±0.3)% vs. (22.6±0.4)% vs. (34.7±0.5)%] and CDK1 expression was reduced significantly. The relative expression of Survivin in siRNA group was lower than negative control group, the difference was statistically significant (P<0.05). Conclusion Inhibition of IGF-Ⅰ receptor can enhance the radiosensitivity of HepG2 cells through cell cycle arrest. Key words: Carcinoma, hepatocellular; Radiation tolerance; Cell cycle; Insulin-like growth factor-Ⅰ receptor; Survivin