Figure 6
miR-106a/b suppresses both STAT3 and HIF-1α expression in breast cancer cells.
(A) The 3′-UTR of the STAT3 and HIF-1α genes contains binding sites for miR-106a/b according to bioinformatic analysis. (B,C) miR-106a/b suppressed the expression of a luciferase reporter gene harbouring the 3′-UTR of STAT3 or HIF-1α. The pGL3 plasmid was modified by adding the human 3′-UTR or the 3′-UTR with mutations in regions complementary to miR-106a/b seed regions behind the firefly luciferase gene. BT474 cells were transiently co-transfected with miR-control or miR-106a or miR-106b together with the indicated luciferase constructs and luciferase activity was analysed 48 h later. (D,E) miR-106a or miR-106b restoration down-regulated STAT3 mRNA in BT474 and SUM102 cells. Cells were transfected with miR-106a, miR-106b or miR-control for 48 hours, then collected for real-time PCR. (F,G) miR-106a or miR-106b restoration down-regulated HIF-1α mRNA in BT474 and SUM102 cells. Cells were transfected with miR-106a, miR-106b or miR-control for 48 hours, then collected for real-time PCR. (H) miR-106a or miR-106b restoration down-regulated STAT3 and HIF-1α in breast cancer cells. Cells were transfected with miR-106a or miR-control for 48 hours, then collected for western blot analysis. The data presented are shown as means ± s.d. collected from three independent experiments. *p < 0.05, **p < 0.01.
