Expression of PDK4 is positively correlated with the resistance to 5-FU-induced apoptosis in colon cancer cells.
A, RKO, HCT116, FET, and CBS cells were treated with different concentrations of 5-FU for 72 h. DNA fragmentation assays were performed. B, Annexin V/PI staining was performed after 2.5 μg/ml of 5-FU treatment for 72 h. Ctr, control. C, Western blotting analysis of cleaved PARP was performed after 5.0 μg/ml 5-FU treatment for 72 h. D, quantitative PCR assays show PDK4 expression in human colon epithelial cells and colon cancer cells (left panel). RT-PCR assays were performed to examine the expression of PDK1–3 in colon cancer cells (right panel). E, Western blotting analysis of PDK4 expression was performed in colon cancer cells. F, quantitative PCR assays of PDK4 expression were performed in colon cancer cells treated with 5.0 μg/ml 5-FU for 72 h (left panel). RT-PCR assays were performed to examine the expression of PDK1–3 in colon cancer cells treated with 5.0 μg/ml of 5-FU for 72 h (right panel). G, Western blotting analysis of PDK4 expression was performed in colon cancer cells treated with 5.0 μg/ml 5-FU for 72 h. The data are presented as the mean ± S.D. of triplicate experiments. ***, p < 0.001.