Abstract
We reported previously that alpha-tocopheryl-succinate (VES) induced apoptosis of cultured human promyelocytic leukemia cells (HL-60) (Free Radic Res 2000;33:407-18). We have now studied the effect of cholesteryl-hemisuccinate (CS) on the fate of HL-60 cells to clarify whether CS has an effect similar to that of VES. CS inhibited the growth of HL-60 cells without differentiation to granulocytes and induced DNA fragmentation and ladder formation. CS inhibited the phosphorylation of pleckstrin homology domain-containing protein kinase B (Akt) and initiated the activation of a caspase cascade. CS triggered the reaction leading to the cleavage of Bid and also released cytochrome c (Cyt. c) from mitochondria. In addition, CS induced mitochondrial membrane depolarization and translocation of Bax to mitochondria in HL-60 cells. However, CS did not induce an increase in the concentration of intracellular calcium ions in HL-60 cells. The membrane depolarization, Cyt. c release, and DNA fragmentation were inhibited by z-VAD-fluoromethylketone (z-VAD-fmk), a pan-caspase inhibitor, but not by cyclosporin A, an inhibitor of membrane permeability transition. These results suggested that CS-induced apoptosis of HL-60 cells might be caused by inhibiting Akt phosphorylation following cleavage of Bid through caspase-8 activation and subsequently via an Apaf complex-caspase cascade pathway.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Chloromethyl Ketones / pharmacology
-
Antineoplastic Agents / pharmacology*
-
Apoptosis*
-
BH3 Interacting Domain Death Agonist Protein
-
Calcium / metabolism
-
Carrier Proteins / metabolism
-
Caspases / metabolism
-
Cell Cycle / drug effects
-
Cell Differentiation / drug effects
-
Cell Division / drug effects
-
Cholesterol Esters / pharmacology*
-
Cyclic AMP / metabolism
-
Cyclosporine / pharmacology*
-
Cytochrome c Group / metabolism
-
DNA Fragmentation / drug effects*
-
Enzyme Activation / drug effects
-
Enzyme Inhibitors / pharmacology
-
HL-60 Cells
-
Humans
-
Leukemia, Myeloid / pathology
-
Membrane Potentials / drug effects
-
Mitochondria / drug effects
-
Mitochondria / enzymology
-
Mitochondria / physiology
-
Phosphorylation / drug effects
-
Protein Serine-Threonine Kinases*
-
Proto-Oncogene Proteins / metabolism
-
Proto-Oncogene Proteins c-akt
-
Proto-Oncogene Proteins c-bcl-2 / metabolism
-
bcl-2-Associated X Protein
Substances
-
Amino Acid Chloromethyl Ketones
-
Antineoplastic Agents
-
BAX protein, human
-
BH3 Interacting Domain Death Agonist Protein
-
BID protein, human
-
Carrier Proteins
-
Cholesterol Esters
-
Cytochrome c Group
-
Enzyme Inhibitors
-
Proto-Oncogene Proteins
-
Proto-Oncogene Proteins c-bcl-2
-
bcl-2-Associated X Protein
-
benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
-
Cyclosporine
-
Cyclic AMP
-
AKT1 protein, human
-
Protein Serine-Threonine Kinases
-
Proto-Oncogene Proteins c-akt
-
Caspases
-
Calcium
-
cholesteryl succinate