title: Arsenic trioxide selectively induces early and extensive apoptosis via the APO2/caspase-8 pathway engaging the mitochondrial pathway in myeloma cells with mutant p53.
abstract: Arsenic trioxide (ATO) is effective in the treatment of acute promyelocytic leukemia (APL) and induces apoptosis in APL cells and in a great variety of other cancer cells. We have previously shown that ATO induces apoptosis in myeloma cells in two different modes depending on p53 status in the cells. In cells expressing mutated p53, ATO induced, G2/M arrest and activation caspase 8 and 3 and rapid and extensive apoptosis. Myeloma cells expressing w.t. p53, ATO induced G1 arrest and delayed apoptosis with activation of caspase 9 and 3. APO2/TRAIL receptor expression was induced in both cell types and APO2/TRAIL synergized with ATO in the induction of apoptosis. Here we tested the effect of ATO on mitochondrial membrane potential (MMP) in myeloma cells expressing mutated or w.t. p53. In myeloma cells expressing mutated p53, depolarization of MMP occurred early, concomitant with induction of APO2/TRAIL, activation of BID and release of AIF, preceding apoptosis. However, in cells expressing w.t. p53, APO2/TRAIL is not induced, BID is not cleaved and depolarization of MMP occurs concurrently with cytochrome c release and apoptosis. These results explain the greater sensitivity to ATO of cells with mutated p53 and suggest perhaps a general mechanism for ATO-induced apoptosis.
authors.affiliation: Department of Medicine/Hematology, University of Texas Health Science Center, San Antonio, Texas 78284, USA.
authors.forename: Cagla
authors.initials: C
authors.lastname: Akay
authors.forename: Yair
authors.initials: Y
authors.lastname: Gazitt
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D051033:Apoptosis Inducing Factor; D051017:Apoptosis Regulatory Proteins; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000378:metabolism / Q000494:pharmacology*; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000378:metabolism; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D005420:Flavoproteins / Q000378:metabolism; D005434:Flow Cytometry; D016158:Genes, p53 / Q000502:physiology*; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D010087:Oxides / Q000378:metabolism / Q000494:pharmacology*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C494829:AIFM1 protein, human; D017304:Annexin A5; D051033:Apoptosis Inducing Factor; D051017:Apoptosis Regulatory Proteins; D001152:Arsenicals; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D005420:Flavoproteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D010087:Oxides; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; C505530:CASP8 protein, human; D053181:Caspase 8; D020169:Caspases; D000077237:Arsenic Trioxide