Anti-miRNA-221 sensitizes human colorectal carcinoma cells to radiation by upregulating PTEN

Figure 6 Ectopic expression of miR-221 affects the radiosensitivity of colorectal carcinoma cells by targeting phosphatase and tensin homolog deleted on chromosome 10. A: miR-221 regulates the phosphatase and tensin homolog deleted on chromosome 10 (PTEN)/AKT pathway. Caco2 cells transfected with negative control or anti-miR-221 were mock treated or irradiated (4 Gy). Total cell lysates were obtained for Western blotting using the indicated antibodies. Caco2 cells were pretreated with or without anti-PTEN-siRNA (80 nmol/L) for 24 h prior to the addition of pre-miR-221 (50 nmol/L) or anti-miR-221 (50 nmol/L); B, C: Real-time RT-PCR and Western blotting showing PTEN mRNA and protein reduced markedly after transfection with anti-PTEN-siRNA (^bP < 0.01 vs blank control and negative control group); D: The status of cell radiosensitivity was determined by colony formation assay. The suppression of Caco2 cell survival fraction at 4 Gy by anti-miR-221 was partially, but not completely, abrogated by anti-PTEN-siRNA (SF₄ from 29.77% to 47.88%). n = 3, mean ± SD; ^bP < 0.01 vs negative control group; ^dP < 0.01 vs sole anti-miR-221 group.