Involvement of p38 MAPK- and JNK-modulated expression of Bcl-2 and Bax in Naja nigricollis CMS-9-induced apoptosis of human leukemia K562 cells.
CMS-9, a phospholipase A(2) (PLA(2)) isolated from Naja nigricollis venom, induced apoptosis of human leukemia K562 cells, characterized by mitochondrial depolarization, modulation of Bcl-2 family members, cytochrome c release and activation of caspases 9 and 3. Moreover, an increase in intracellular Ca2+ concentration and the production of reactive oxygen species (ROS) was noted. Pretreatment with BAPTA-AM (Ca2+ chelator) and N-acetylcysteine (NAC, ROS scavenger) proved that Ca2+ was an upstream event in inducing ROS generation. Upon exposure to CMS-9, activation of p38 MAPK and JNK was observed in K562 cells. BAPTA-AM or NAC abrogated CMS-9-elicited p38 MAPK and JNK activation, and rescued viability of CMS-9-treated K562 cells. SB202190 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor) suppressed CMS-9-induced dissipation of mitochondrial membrane potential, Bcl-2 down-regulation, Bax up-regulation and increased mitochondrial translocation of Bax. Inactivation of PLA(2) activity reduced drastically the cytotoxicity of CMS-9, and a combination of lysophosphatidylcholine and stearic acid mimicked the cytotoxic effects of CMS-9. Taken together, our data suggest that CMS-9-induced apoptosis of K562 cells is catalytic activity-dependent and is mediated through mitochondria-mediated death pathway triggered by Ca2+/ROS-evoked p38 MAPK and JNK activation.
Chen
Ying-Jung
YJ
Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Liu
Wen-Hsin
WH
Kao
Pei-Hsiu
PH
Wang
Jeh-Jeng
JJ
Chang
Long-Sen
LS
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis / Q000235:genetics; D015153:Blotting, Western; D020169:Caspases / Q000096:biosynthesis; D002470:Cell Survival / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004546:Elapid Venoms / Q000633:toxicity*; D005227:Fatty Acids / Q000633:toxicity; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D020014:K562 Cells; D048670:MAP Kinase Kinase 4 / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D054467:Phospholipases A2 / Q000633:toxicity*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D017382:Reactive Oxygen Species / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
D051017:Apoptosis Regulatory Proteins; C550860:CMS-9 protein, Naja nigricollis; D002614:Chelating Agents; D004546:Elapid Venoms; D005227:Fatty Acids; D016166:Free Radical Scavengers; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D054467:Phospholipases A2; D020169:Caspases