ABSTRACT
Objective To investigate the effect of DDX46 gene on the radiosensitivity of colorectal cancer cells and underlying mechanism.Methods SW480 cells transfected with DDX46 RNAi or its empty plasmid by lentivirus were set as experimental group and control group,respectively.After 72 h of transfection,the cells were irradiated with 4 Gy X rays.The cell viabilities of these two groups were detected by CCK-8 assay.The number of γ-H2AX foci and the expressions of some key proteins related to DNA damage repair were detected by immunofluorescence technique and Western blot at 24 h after irradiation.Results At 24 h after 4 Gy irradiation,the cell vitality of experimental group was decreased to (15.02±3.92)％(t=-4.696,P ＜ 0.05) of control and(17.43 ±1.83)％(t=4.844,P＜0.01) of nonirradiated cells,but there was no significant difference between 4 Gy irradiated control cells and nonirradiated cells.Meanwhile,compared with the control group,the ATM protein expression level (t =7.530,P ＜0.01) and the number of γ-H2AX foci (t =-3.108,P ＜0.05) were significantly increased in the experimental SW480 cells,while the expression levels of p-ATM and Rad50 were significantly reduced (t =4.260,4.260,P ＜ 0.05),and the protein levels of DNA-PK in these two groups had tiny difference.Conclusions DDX46 RNA silence increases the radiation sensitivity of SW480 cells by inhibiting ATM activation and DNA repair.