UHRF1 expression inhibition by RNA interference enhances the radiosensitivity of esophageal cancer cells / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the effect of UHRF1 expression inhibition by RNA interference on the radiosensitivity of esophageal cancer cell line TE-1 and its mechanism.Methods Short hairpin RNA (shRNA) targeting UHRF1 gene was introduced into TE-1 cells by lentivector-mediated transfer.The cells were divided into three groupsnon-transfected group,negative control (NC)-shRNA-transfected group,and UHRF1-shRNA-transfected group.The mRNA and protein expression levels of UHRF1 in TE-1 cells were measured by RT-PCR and Western blot before and after transfection.After transfection and X-ray radiation,the radiosensitivity of TE-1 cells was evaluated by colony formation assay; the cell cycle and cell apoptosis were determined by flow cytometry; the γ-H2AX (as a marker of DNA damage) level was measured by Western blot.Results After transfection with UHRF1-shRNA,the mRNA and protein expression levels of UHRF1 were significantly decreased in TE-1 cells,as compared with those in the NC-shRNA-transfected group and non-transfected group (0.11 vs 0.96 and 0.98,F =124.21,P =0.000;0.10 vs 0.89 and 0.94,F =125.25,P =0.000).The UHRF1-shRNA-transfected group had sensitization enhancement ratios of 1.53 (D0 ratio) and 1.95 (Dq ratio).X-ray radiation could cause G2/M arrest and increase apoptotic rate and γ-H2AX expression in TE-1 cells.Compared with the two control groups,the UHRF1-shRNA-transfected group showed significantly less G2/M arrest (F =500.15,P =0.000),a significantly higher apoptotic rate (F =100.10,P =0.000),and significantly higher residual γ-H2AX expression (F =61.00,P =0.000) at 24 hours after X-ray radiation.Conclusions RNA interference can effectively inhibit the UHRF1 expression and enhance the radiosensitivity of TE-1 cells.The mechanism may be related to cell cycle regulation,cell apoptosis,and DNA damage repair.