Effect and mechanism of down-regulating REV7 expression on the radiosensitivity of human colon cancer cell HCT116

Objective: To evaluate the effect and mechanism of down-regulating the expression of REV7 on the radiosensitivity of human colon cancer cell HCT116. Methods: HCT116 cells were cultured and the expression of REV7 was down-regulated by RNA interference technique. HCT116 cells were divided into the blank group, negative control transfected with negative RNA oligo group and REV7 expression down-regulation transfected with REV7 RNA oligo group, respectively. The cell proliferation was determined by colony formation assay. The expression levels of the proteins of relevant genes were detected by Western blot. The level of cell apoptosis and non-homologous end joining was evaluated. Results: The colony formation rate was significantly reduced in THE REV7 siRNA group after 6 Gy irradiation (P < 0.05). The down-regulating efficiency rate of REV7 gene was > 60% in the REV7 siRNA group. The expression levels of γ H₂AX and Caspase 9 were significantly up-regulated, whereas those of KU80 and XRCC4 were remarkably down-regulated in the REV7 siRNA group (all P < 0.05). Conclusions: The radiosensitivity of human colon cancer cell HCT116 can be increased by down-regulating the expression of REV7. The underlying mechanism may be related to the lower incidence rate of non-homologous end joining. (authors)