Involvement of both endoplasmic reticulum- and mitochondria-dependent pathways in cardiotoxin III-induced apoptosis in HL-60 cells.
Cardiotoxin (CTX) III, a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. In the present study, we investigated the mechanisms underlying the anticancer activity of CTX III in human leukaemia (HL-60 cells). Cardiotoxin III activated the endoplasmic reticulum (ER) pathway of apoptosis in HL-60 cells, as indicated by increased levels of calcium and glucose-related protein 78 (Grp78), and triggered the subsequent activation of micro-calpain and caspase 12. In addition, CTX III initiated the mitochondrial apoptotic pathway in HL-60 cells, as evidenced by an increased Bax/Bcl-2 ratio, the release of cytochrome c and activation of caspase 9. In the presence of 50 micromol/L Z-ATAD-FMK (a caspase 12 inhibitor) and 100 micromol/L Z-LEHD-FMK (a caspase 9 inhibitor), the CTX III-mediated activation of caspase 9 and caspase 3 was significantly reduced. There was no significant effect of the caspase 12 inhibitor Z-ATAD-FMK on mitochondrial cytochrome c release. Cardiotoxin III-mediated activation of caspase 12 was not abrogated in the presence of the caspase 9 inhibitor Z-LEHD-FMK, indicating that caspase 12 activation was not downstream of caspase 9. These results indicate that CTX III induces cell apoptosis via both ER stress and a mitochondrial death pathway.
Chien
Ching-Ming
CM
Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan.
Yang
Sheng-Huei
SH
Chang
Long-Sen
LS
Lin
Shinne-Ren
SR
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism; D053454:Caspase 12 / Q000378:metabolism; D004179:Cobra Cardiotoxin Proteins / Q000494:pharmacology*; D045304:Cytochromes c / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000502:physiology*; D000091342:Endoplasmic Reticulum Chaperone BiP; D018922:HL-60 Cells; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology*; D018832:Molecular Chaperones / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects
D004179:Cobra Cardiotoxin Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C082202:cardiotoxin III, Naja naja atra; D045304:Cytochromes c; C506444:CASP12 protein, human; D002154:Calpain; D053454:Caspase 12; C449002:mu-calpain; D002118:Calcium