Objective To investigate the effect and mechanism of recombinant human CC16 protein (rhCC16) on cigarette smoke extract (CSE)-induced senescence of human bronchial epithelial cells (HBECs). Methods CCK-8 assay was used to evaluate the cell viability in HBECs after treated with 0%, 1%, 2.5%, 5%, 7.5% and 10% CSE and/or 0, 10, 100, 250 and 500 ng/mL rhCC16.β-galactosidase staining was used to observe the activity of the enzyme in control, CSE, and CSE+rhCC16 treated HBECs.The mRNA levels of P16 and P21 in above cell groups were detected by real-time fluorescence quantitative PCR (qPCR), and the protein levels of P16, P21, p-P53, P38, p-P38, ERK1/2 and p-ERK1/2 were detected with Western blot in control group, CSE and CSE+rhCC16 groups. Results Compared with the control group, 5% CSE stimulation for 72 h or the treatment of 500 ng/mL or lower dose of rhCC16 had no significant effect on cell viability of HBECs.Stimulation 5% CSE for 72 h resulted in significantly higher positive rate to β-galactosidase staining (P < 0.05), elevated mRNA and protein levels of P16 and P21(P < 0.05), and enhanced protein levels of p-P53, p-P38 and p-ERK1/2(P < 0.05) when compared with the control group.Compared with the simple CSE stimulation, 250 ng/mL rhCC16 treatment decreased positive rate to β-galactosidase staining (P < 0.05), reduced mRNA and protein levels of P16 and P21(P < 0.05) and protein levels of p-P53, p-P38 and p-ERK1/2(P < 0.05). Conclusion rhCC16 inhibits CSE-induced cellular senescence of HBECs, which may due to its suppression in P38 MAPK and ERK1/2 signaling pathway.
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