Susceptibility to apoptosis is restored in human leukemia HCW-2 cells following induction and stabilization of the apoptotic effector Bak.
We demonstrate that treatment of HCW-2 cells, an apoptotic resistant variant of the human HL-60 promyelocytic leukemia cell line with phorbol-12-myristate acetate (PMA), induced differentiation along the monocytic lineage. During this process there was a dramatic increase in the mitochondrial levels of the apoptosis effector, Bak, due to the stabilization of bak mRNA, which was correlated with the sensitization of HCW-2 cells to respond to the apoptotic effect of staurosporine (STS). Treatment of PMA-differentiated, but not undifferentiated, HCW-2 cells induced processing of Bid, substantial efflux of cytochrome c from mitochondria to the cytosol, activation of caspase-3 and apoptosis. The biological significance of the increased mitochondrial Bak in differentiated HCW-2 cells was supported by the finding that transient transfection of a bak cDNA into HCW-2 cells conferred sensitivity to STS-triggered apoptosis, as determined by pro-caspase-3 processing, cytochrome c efflux and DNA fragmentation. Our results suggest that the induction of Bak, upon monocytic differentiation, may be a critical event that regulates the apoptotic sensitivity of differentiated HCW-2 cells. Oncogene (2000) 19, 4108 - 4116
Chatterjee
D
D
Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 69 Brown Street, Providence, Rhode Island, RI 02912 USA.
Pantazis
P
P
Li
G
G
Bremner
T A
TA
Hendrickson
E A
EA
Wyche
J H
JH
D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein; D015152:Blotting, Northern; D015153:Blotting, Western; D002273:Carcinogens / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation; D003574:Cytochrome c Group / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D050998:bcl-2 Homologous Antagonist-Killer Protein
C494772:BAK1 protein, human; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002273:Carcinogens; D002352:Carrier Proteins; D003574:Cytochrome c Group; D004792:Enzyme Precursors; D008565:Membrane Proteins; D050998:bcl-2 Homologous Antagonist-Killer Protein; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D016186:Receptor, Macrophage Colony-Stimulating Factor; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate