Lethal effect of RI-1 on MSH2-deficient colorectal cancer cells / 基础医学与临床

ABSTRACT

Objective To explore the lethal action and possible mechanism of RI-1, a RAD51 inhibitor, on MSH2 deficient colorectal cancer cells.Methods The expression of MSH2 protein level was assessed by Western blot, and the sensibility of human colorectal cancer cells to RI-1 (10, 20, 30, 40 and 50 μmol/L)was measured by MTT method.Lentivirus vectors MSH2-shRNA and Neg-shRNA (negative control) were constructed and transfected into HT29 cell.Apoptosis and DNA damage of cells treated with RI-1(40 μmol/L)were detected by flow cytometry and Single cell gel electrophoresis respectively.In addition, the formation of γ-H2AX foci was analyzed by immunofluorescence.Results Compared with control, MSH2-deficient HCT8 cells had obviously apoptosis(P<0.01);in HCT8 and HT29 Shmsh2 cells, tail DNA%, tail length, tail moment and olive tail moment were markedly increased(P<0.05),and the number of γ-H2AX focus were increased(P<0.01).Conclusions RAD51 inhibitor RI-1 selectively kills MSH2 deficient colorectal cancer cells by increasing DNA damage.