Involvement of Caspase-3 Activity and Survivin Downregulation in Cinobufocini-Induced Apoptosis in A 549 Cells

Abstract

Cinobufocini injection is a preparation containing water-soluble components of the toad skin. The aim of the present study was to investigate the apoptosis of human lung adenocarcinoma cell line A 549 induced by cinobufocini. A 549 or HLF-1(human lung fibroblast) cells were treated with cinobufocini at different concentrations for 24 and 48 h, respectively. The proliferation of cells was detected with the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Morphology of cells was carried out with scanning electronic microscopy (SEM) and Hoechst 33258 staining. The apoptosis rate was examined by flow cytometry. The expression of survivin was examined with RT-PCR and Western blot assay. The caspase-3 and caspase-7 activities were detected with caspase colorimetric protease assay. We found that cinobufocini significantly inhibited tumor growth of A 549 cells in a dose- and time-dependent manner without damaging non-cancerous cells (HLF-1) and induced granular apoptotic bodies of A 549 cells. Next, cinobufocini increased the percentage of cells in G1 phase and decreased the percentage of cells in S phase in A 549 cells. Furthermore, cinobufocini downregulated the expression of survivin mRNA and protein. Finally, cinobufocini upregulated caspase-3 activity. We concluded that cinobufocini induces apoptosis of A 549 cells, which is associated with the decreasing expression of survivin mRNA and protein, increasing caspase-3 activity of A 549 cells.