Fig. 5.

miR-143 inhibits ERK signaling via IGF-IR/IRS1 in long-term Cr (VI)–treated BEAS-2B. (A) BEAS-Cr cells were transfected with 50nM of an siRNA scramble control or an siRNA SMARTpool against IGF-IR or IRS1 for 72 h. The IGF-IR, IRS1, p-AKT, AKT, p-ERK, and ERK protein levels were assessed by Western blotting. (B) The expression levels of IGF-IR, IRS1, p-AKT, AKT, p-ERK, and ERK in eight BEAS-Cr clones were assessed by Western blotting. The representative protein bands were shown in the top panel, and relative protein expression levels from three independent experiments were shown in the lower panel. (C) BEAS-Cr cells were transiently transfected with 25nM miR-143 or negative miR control precursor and harvested 70h later to analyze p-ERK and ERK expression levels.