Inhibition of p38 significantly abolished the inhibitory effect of MBL on cellular proliferation.
Monocytes were pretreated with 0.2% DMSO vehicle or inhibitors against PI3K (LY294002, 5 μM), ERK (U0126, 5 μM), p38 (SB203580, 10 μM), and JNK (SP600125, 5 μM) at 37°C for 0.5 h, and then treated with MBL at 20 μg/ml for 24 h, 48 h and 72 h. Cell proliferation rates were determined by CCK-8 assay (A). The expression levels of p21 (B), cyclinD1 (C), and Cdk4 (D) were measured by real-time RT-PCR. Each bar represents the mean ± S.D. of three independent experiments. Indicated levels of statistical significance were; * p<0.05, ** p<0.01, *** p<0.001 as compared with the control or DMSO cultures.