Effect of berbamine on apoptosis in human pulmonary carcinoma cell A549 and its mechanism

Objective To investigate the effect of berbamine(BBM) on the induction of apoptosis in human lung cancer cell A549 cells and the activity of TNF-α-JNK signaling pathway.Methods After the A549 cells being treated with BBM at different concentration,the inhibitory effect of BBM on proliferation was detected by MTT assay.Cell morphological changes were detected by light microscope.Alteration of apoptosis rate of A549 cells was determined by Annexin V/PI double staining.Western blotting was used to detect the activity of apoptosis-related proteins,including Bcl-x,Caspase-3,and PAPR.The expressions of c-jun N-terminal kinase(JNK) and p-JNK were determined by Western blotting.Changes of tumor necrosis factor-alpha(TNF-α) were detected by fluorescent quantitative PCR and ELISA,respectively.Finally,the impacts of BBM on the proliferation and apoptosis of A549 cells were detected in the absence or presence of a JNK inhibitor.Results BBM significantly inhibited the growth of A549 cells in a dose-dependent manner.The IC50of 24 h was 9.01 μmol/L.Cells treated with BBM showed the typically morphological characteristics of apoptotic cells.Annexin V/PI double staining test indicated that BBM could induce the apoptosis of A549 cells in a dose-dependent manner.The early apoptotic population of cells treated with 10 μmol/L BBM was 13.8%,which was 5.6 times higher than that of the control.BBM decreased the expression of anti-apoptotic protein Bcl-x and increased the activity of proapoptotic proteins of caspase-3 and PARP.The mRNA and the protein expression levels of TNF-α were significantly increased by BBM treatment.The p-JNK expression was also dramatically up-regulated after BBM treatment.The effects of BBM on the proliferation and apoptosis in A549 cells were significantly reduced when JNK pathway was blocked.Conclusion BBM could inhibit the growth and induce the apoptosis of A549 cells,and its mechanism may be related to the activated TNF-α-JNK signaling pathway.