Abstract: Objective To investigate the effects of PM_2.5 on oncogene expression via p38MAPK signaling pathway in human bronchial epithelial （HBE） cells. Methods Control group, PM_2.5 group, SB203580 group and PM_2.5+ SB203580 group were established. HBE cells were treated with 10 µmol/L p38MAPK inhibitor SB203580 for 30 min, then cultured in serum-free DMEM medium for 24 h as SB203580 group; HBE cells were treated with 50 μg/mL PM_2.5 for 24 h as PM_2.5 group; HBE cells were treated with10 µmol/L SB203580 for 30 min, then exposed to 50 μg/mL of PM_2.5 for 24 h as the PM_2.5+SB203580 group. The mRNA and protein expression levels of C-MYC, C-FOS, K-RAS, P53 and p38MAPK were detected by real-time PCR and Western blot. Results PCR results showed that compared with the control group, the mRNA expression of C-MYC, C-FOS, K-RAS, p38MAPK in the PM2.5 group increased by 54.0%, 49.2%, 96.1%, 74.1%, and P53 decreased by 49.1%. Compared with the PM_2.5 group, the mRNA expression of C-MYC, C-FOS, K-RAS and p38MAPK in the PM_2.5+SB203580 group decreased by 21.4%, 20.8%, 39.3%, 21.4%, and P53 increased by 43.1% （P<0.01 or P<0.05）. Western blot results showed that compared with the control group, the protein expression levels of C-MYC, C-FOS, K-RAS, p38MAPK in the PM_2.5 group increased by 110.6%, 46.7%, 35.5%, 82.8%, and P53 decreased by 42.7% （all P<0.01）. Compared with the PM_2.5 group, the protein expression levels of C-MYC, C-FOS, K-RAS, p38MAPK in the PM2.5+SB203580 group decreased by 37.7%, 16.2%, 19.6%, 25.9%, and P53 increased by 43.5% （P<0.01 or P<0.05）. Conclusion The p38MAPK inhibitor obviously influenced the effects of PM_2.5 on oncogene expression, indicating that p38MAPK signaling pathway plays an important role in PM_2.5-induced oncogene expression.

Key words: PM_2.5, Mitogen-activated protein kinase, p38MAPK, Signal pathway, Human bronchial epithelial cells, Oncogene