Effect of cigarette smoke extract on JNK, p38MAPK expressions in MIN6 cells

Objective To investigate the effect of cigarette smoke extract (CSE) on expressions of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) in MIN6 cells.Methods MIN6 cells in logarithmic growth period were cultured in vitro and then treated with different concentrations of CSE (20,50,100,200 μg/mL) and a vehicle (control) group was also established.After 48 hours' treatment of CSE,the change in morphology of the cells was observed with inverted microscope and cholecystokinin (CCK-8) was used to assess CSE-mediated anti-proliferative effect on MIN6 cells.Meanwhile,Western blot analysis was applied to determine cellular protein expressions of extracellular-signal-regulated kinase (ERK),JNK,p38MAPK,and corresponding phosphorylation level.Results Compared with the control group,obvious abnormal morphology was found in the cells under the treatment of 100 μg/mL and 200 μg/mL CSE,including nuclear condensation and spindle like change.Compared with the control group,CSE at different dosages significantly inhibited the viability of MIN6 cells,with the cell viabilities of 97.32±2.67%,94.67±5.33%,87.71±12% (all P<0.05),and 74.23±25.80%(P<0.01) for the cells treated with 20,50,100,and 200 μg/mL CSE,respectively.In addition,CSE effectively activated the JNK and p38MAPK signaling pathway.With the increment of CSE concentration,the phosphorylation level significantly increased when compared to that of the control group (P<0.05).Conclusion Cigarette smoke extract could decrease the cell viability of MIN6 cells and the effect may due to the increased expressions of p-JNK and p-p38MAPK.