[c-Jun NH2-terminal kinase and extracellular signal-regulated protein kinase signaling pathways in regulation of benzo(a)pyrene-induced c-Jun activation in human embryo lung fibroblasts]

Abstract

Objective: To investigate the role of mitogen activated protein kinases (MAPKs) signaling pathways in the regulation of benzo(a)pyrene (B(a)P)-induced c-Jun activation in human embryo lung fibroblasts (HELFs).

Methods: HELFs were cultured with 2.0 micromol/L B(a)P for various time (0, 3, 6, 12, 24 h) or with various concentration of B(a)P (0.0, 0.5, 1.0, 2.0 micromol/L) for 12 h. Western blot was performed to examine the effect of B(a)P on c-Jun activation. The dominant negative mutants of p38, c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated protein kinase (ERK) were applied to establish stable transfectant, and to detect the relationship of MAPK signal molecules and c-Jun activation in B (a) P-treated cells.

Results: B(a)P treatment resulted in a marked activation of c-Jun in time-dependent manner with a peak at 12 h (the densitometric ratios of phosphorylated c-Jun Ser63, Ser73 to actin were 20.1, 15.2 times for control respectively) and in dose-dependent manner. However, there was no evident change on total c-Jun expression in B(a)P-treated HELFs. Moreover, B(a)P-induced activation of c-Jun was inhibited by stable expression of dominant negative mutants of JNK or ERK, but not by dominant negative mutant of p38.

Conclusion: JNK and ERK signaling pathways, but not p38 pathway regulate B(a)P-induced c-Jun activation in HELFs.