Taiwan cobra cardiotoxins induce apoptotic death of human neuroblastoma SK-N-SH cells mediated by reactive oxygen species generation and mitochondrial depolarization.
Although Naja naja atra cardiotoxin 3 (CTX3) and cardiotoxin 4 (CTX4) showed different cytotoxicity toward human neuroblastoma SK-N-SH cells, the two toxins induced apoptotic death on SK-N-SH cells. The apoptosis signals of CTX3 and CTX3 included ROS generation, increase in mitochondrial permeability transition, cytochrome c release to the cytosol and activation of caspase-9 and -3. However, CTX3 quickly induced the effects with higher magnitude compared with CTX4. ROS production and subsequent apoptotic cell death in CTX-treated cells were partly blocked by the antioxidant 2,3-dihydroxybenzoic acid. Nevertheless, mitochondria alteration and cytosolic cytochrome c release were not significantly attenuated by the antioxidant. Cell death was not completely inhibited by caspase-3 inhibitor. Moreover, cyclosporine A, an inhibitor of mitochondrial permeability transition, slightly decreased CTX-induced ROS generation by approximately 15%. Taken together, our data indicate that N. naja atra CTXs induce ROS generation that is not wholly dependent on mitochondrial dysfunction, and that the cytotoxic potency of CTX3 and CTX4 on SK-N-SH cells is, at least in part, correlated with their capability in inducing ROS generation and mitochondrial alterations.
Chen
Ku-Chung
KC
Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Chiou
Yi-Ling
YL
Kao
Pei-Hsiu
PH
Lin
Shinne-Ren
SR
Chang
Long-Sen
LS
D000818:Animals; D054715:Cardiotoxins / Q000737:chemistry / Q000633:toxicity*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004546:Elapid Venoms / Q000737:chemistry; D017815:Elapidae / Q000378:metabolism*; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D008928:Mitochondria / Q000187:drug effects; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*
D054715:Cardiotoxins; D004546:Elapid Venoms; D017382:Reactive Oxygen Species