Effect of chemotherapeutic agents on DNA damage and apoptosis in HCT116, HCT116+3 and HCT116+3+5 cells.

<p>A, B, Analysis of pH2AX and pChk2 expression and PARP cleavage in HCT116, HCT116+3, and HCT116+3+5 cells treated with 5-FU, SN-38 or oxaliplatin for 48 h and compared to untreated control cells. C, Analysis of caspase-3/7 activity in HCT116, HCT116+3 and HCT116+3+5 cells treated with 5-FU, SN-38 or oxaliplatin (48 h). Data are shown as mean ± standard errors from 3 independent experiments. Statistical significance was determined by a two-sided Student's t test (* P<0.05; † P<0.01).