Figure 5.
Effect of HLA on MAP kinase-dependent signaling in melan-a cells. (A) Cells (5 × 105 cells/mL) were cultured for 24 h, and the medium was replaced with fresh medium containing various concentrations of test compounds or arbutin for the indicated times. Phosphorylation of JNK, ERK, and p38 MAPK was analyzed using phospho-specific JNK, ERK, and p38 MAPK antibodies. Equal protein loading was checked using β-actin antibodies. Numbers (each phospho-antibody) mean the relative band intensity. (B) OISEA was cotreated with selective inhibitors of p38 (SB239063), ERK (U0126), and JNK (SP600125) signaling molecules in melan-a cells. Melanin content was determined. Each determination was made in triplicate, and the data represent the means ± SD. # p < 0.05, ** p < 0.01, versus the control group.