STAT3 knockdown increase the level of PCAT29 expression.
(A, B) DU145 and LNCaP cells were transfected with either scramble siRNA sequence or siSTAT3 (10 nM) for 24 h then treated with IL-6 (10 ng/ml) for another 24 h. Cells were then used to determine PCAT29 level by real-time RT-PCR. IL-6 suppressed PCAT29 expression in both DU145 and LNCaP cells which were pretreated with scrambled siRNA but not following transfection with siSTAT3. (C, D) DU145 and LNCaP cells were transfected with either scramble or siSTAT3 (10 nM) for 24 h, then treated with IL-6 (10 ng/ml) for 24 h, and used to determine miR-21 levels by TaqMan® real-time PCR. The levels of miR-21 were increased by IL-6 in the cells treated with scrambled siRNAs but not after transfection with siSTAT3. In fact, siSTAT3 reduced both basal and IL-6 stimulated miR-21 expression. (E, F) DU145 and LNCaP cells were transfected with a scrambled sequence (anti-miR-scr) or anti-miR-21 (30ng/ml) for 24 h and then treated with IL6 (10 ng/ml) for 24 h. The expression of miR-21 was the determined by TaqMan® real-time PCR. IL-6 increased miR-21 in the group treated with the scrambled sequence but its effects were significantly reduced by anti-miR-21 in DU145 cells and completely reversed in LNCaP cells. Data represent the mean ± SEM of at least 3 independent experiments. Asterisks (*), (**), and (***) indicate statistically significantly difference (p < 0.05) from scramble, from scramble +IL-6 and from anti-miR-21, respectively.