TPA-induced miR-101 in HepG2 is mediated by ERK signaling pathway. (A) HepG2 cells were cultured serum-free medium for 24 hrs, pre-treatment of specific MAPK signaling inhibitors U0126 10 μM for 0.5 h, and treated with TPA 100 nM for 8 hrs. Total RNAs were isolated from indicated samples with standard procedures. The expression level of miR-101 was normalized to miR-16 and expressed as fold change using control sample as baseline. Results shown are averages of three independent experiments performed in triplicates. (B) Protein levels of p-ERK, ERK, p21 and β-actin after TPA and ERK inhibitor treatment.