Arsenic trioxide sensitizes promonocytic leukemia cells to TNFalpha-induced apoptosis via p38-MAPK-regulated activation of both receptor-mediated and mitochondrial pathways.
Treatment with the anti-leukemic drug arsenic trioxide (As(2)O(3), 1-4 microM) sensitizes U937 promonocytes and other human myeloid leukemia cell lines (HL60, NB4) to apoptosis induction by TNFalpha. As(2)O(3) plus TNFalpha increases TNF receptor type 1 (TNF-R1) expression, decreases c-FLIP(L) expression, and causes caspase-8 and Bid activation, and apoptosis is reduced by anti-TNF-R1 neutralizing antibody and caspase-8 inhibitor. The treatment also causes Bax translocation to mitochondria, cytochrome c and Omi/HtrA2 release from mitochondria, XIAP down-regulation, and caspase-9 and caspase-3 activation. Bcl-2 over-expression inhibits cytochrome c release and apoptosis, and also prevents c-FLIP(L) down-regulation and caspase-8 activation, but not TNF-R1 over-expression. As(2)O(3) does not affect Akt phosphorylation/activation or intracellular GSH content, nor prevents the TNFalpha-provoked stimulation of p65-NF-kappaB translocation to the nucleus and the increase in NF-kappaB binding activity. Treatments with TNFalpha alone or with As(2)O(3) plus TNFalpha cause TNF-R1-mediated p38-MAPK phosphorylation/activation. P38-MAPK-specific inhibitors attenuate the As(2)O(3) plus TNFalpha-provoked activation of caspase-8/Bid, Bax translocation, cytochrome c release, and apoptosis induction. In conclusion, the sensitization by As(2)O(3) to TNFalpha-induced apoptosis in promonocytic leukemia cells is an Akt/NF-kappaB-independent, p38-MAPK-regulated process, which involves the interplay of both the receptor-mediated and mitochondrial executioner pathways.
Amrán
Donna
D
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.
Sánchez
Yolanda
Y
Fernández
Carlos
C
Ramos
Adrián M
AM
de Blas
Elena
E
Bréard
Jacqueline
J
Calle
Consuelo
C
Aller
Patricio
P
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D045744:Cell Line, Tumor; D016207:Cytokines / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007938:Leukemia / Q000201:enzymology* / Q000473:pathology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D022423:Myeloid Cells / Q000187:drug effects / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism; D010087:Oxides / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D000970:Antineoplastic Agents; D001152:Arsenicals; D016207:Cytokines; D004791:Enzyme Inhibitors; D016328:NF-kappa B; D010087:Oxides; D019253:Proto-Oncogene Proteins c-bcl-2; D011956:Receptors, Cell Surface; D014409:Tumor Necrosis Factor-alpha; D051057:Proto-Oncogene Proteins c-akt; D048051:p38 Mitogen-Activated Protein Kinases; D005978:Glutathione; D000077237:Arsenic Trioxide