Interactions between 2-fluoroadenine 9-beta-D-arabinofuranoside and the kinase inhibitor UCN-01 in human leukemia and lymphoma cells.
Interactions between the purine analogue 2-fluoroadenine 9-beta-D-arabinofuranoside (F-ara-A) and the kinase inhibitor UCN-01 have been examined in human leukemia cells (U937 and HL-60) with respect to induction of mitochondrial damage, caspase activation, apoptosis, and loss of clonogenic survival. Simultaneous or subsequent exposure of F-ara-A-treated cells (2 microM) to UCN-01 (100 nM) resulted in a marked potentiation of apoptosis, manifested by loss of mitochondrial membrane potential (delta psi(m)), cleavage/activation of procaspase-9 and procaspase-3, DNA fragmentation, and degradation of poly-ADP(ribosyl) polymerase. Coadministration of UCN-01 with F-ara-A was also associated with diminished phosphorylation of the cdc25 phosphatase. In contrast, exposure of cells to the sequence UCN-01, followed by F-ara-A, resulted in only a modest increase in apoptotic cells. The ability of UCN-01 to potentiate F-ara-A-mediated lethality was not mimicked by the selective PKC inhibitor bisindolylmaleimide, nor did treatment of cells with UCN-01 enhance formation of F-ara-ATP or increase incorporation of [3H]F-ara-A into DNA. Enhanced apoptosis in cells exposed sequentially or simultaneously to F-ara-A and UCN-01 was accompanied by a substantial reduction in colony formation (e.g., to 0.01% of control values). Cotreatment with UCN-01 also increased F-ara-A-mediated apoptosis and loss of delta psi(m) in U937 cells ectopically expressing Bcl-2, although not to the same extent as that observed in empty-vector controls. Finally, simultaneous exposure (24 h) of malignant B lymphocytes from the pleural effusion of a patient with indolent non-Hodgkin's lymphoma to F-ara-A and UCN-01 ex vivo resulted in a striking increase in apoptosis, as determined by terminal deoxynucleotidyltransferase-mediated nick end labeling assay. These findings indicate that UCN-01 increases F-ara-A-induced mitochondrial damage and apoptosis in human leukemia cells in a sequence-dependent manner, and that these events occur in at least some primary human lymphoma cells.
Department of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298, USA.
S
S
Harvey
R
R
Decker
Y
Y
Dai
G
G
Schaefer
L
L
Tang
L
L
Kramer
P
P
Dent
S
S
Grant
D000470:Alkaloids / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000378:metabolism*; D017209:Apoptosis; D001088:Arabinonucleotides / Q000096:biosynthesis; D015153:Blotting, Western; D004347:Drug Interactions; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000378:metabolism*; D018922:HL-60 Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007938:Leukemia / Q000378:metabolism* / Q000473:pathology; D008223:Lymphoma / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D019311:Staurosporine / Q000031:analogs & derivatives; D020298:U937 Cells / Q000187:drug effects; D014740:Vidarabine / Q000031:analogs & derivatives* / Q000378:metabolism*
D000470:Alkaloids; D000970:Antineoplastic Agents; D001088:Arabinonucleotides; D004791:Enzyme Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; C034957:2-fluoro-araATP; C054852:7-hydroxystaurosporine; D011493:Protein Kinase C; D014740:Vidarabine; D019311:Staurosporine; C024352:fludarabine