miR-202 expression blocks the activation of Raf-1/MEK/ERK signaling by suppressing K-Ras. ESCs were transfected with miR-202 mimics and pcDNA-k-Ras or co-transfected with both miR-202 mimics and pcDNA-K-Ras for 24 h before the cells were harvested for subsequent experiments. (A) Representative western blotting images of p-Raf1, Raf1, MEK, p-MEK, ERK1/2 and p-ERK1/2 protein levels. (B) The bands were semi-quantitatively analyzed using the Image J software, which were normalized to β-actin density. Data represent the mean ± SD from three independent experiments. *P<0.05 and **P<0.01 vs. Control, non-treated ESCs. ##P<0.01 vs. miR-202 mimics. p, phosphorylated; ESCs, endometrial stromal cells isolated from ectopic endometriosis tissues; miR, microRNA; NC, negative control.