The effect of ~(60) CO gamma ray on the expression of cyclin B1 and proliferating cell nuclear antigen in nasopharygeal carcinoma cell line CNE-2

Objective To investigate the effects of~(60) Co gamma ray on CNE-2 cell cycle distribution, the expression of cyclin B1 and proliferating cell nuclear antigen(PCNA).Methods Propidium iodide(PI) simple staining and flow cytometry(FC) were used to test the cell cycle. The expression of cyclin B1 and PCNA mRNA were detected by combining RT-PCR with semi-quantitative analysis.Results The cells of G_1, S or G_2-phase fraction increased at different time after CNE-2 cells exposed to the fractionation of the~(60) Co gamma ray dose(4.0,6.0 or 8.0 Gy).The expression of PCNA was suppressed after radiation on first day with fractionated doses of 4.0,6.0 or 8.0 Gy(P0.05),there was not significant difference in the expression of PCNA after radiation on third and fifth day with fractionated doses of 4.0,6.0 or 8.0Gy(P0.05).The expression of cyclin B1 mRNA was suppressed after radiation(P0.05), but there was not significant difference in the expression of cyclin B1 among irradiated groups(P0.05).Conclusion G_1,S and G_2 phase delay were observed after CNE-2 cells exposed to the fractionation of the~(60)Co gamma ray . CNE-2 cell cyclin B1 and PCNA expression are suppressed by~(60)Co gamma ray radiation,but the inhibition of gamma ray on PCNA and cyclin B1 were not dose-dependent.