title: Cyclic adenosine monophosphate inhibits nitric oxide-induced apoptosis in human leukemic HL-60 cells.
abstract: Previously we reported that phorbol ester, a protein kinase C (PKC) activator, exhibits a unique pattern of potentiation of nitric oxide (NO)-related apoptosis in HL-60 human promyelocytic leukemia cells. Here we show that elevation of intracellular cAMP could protect HL-60 cells from NO- or NO plus PMA-induced DNA damage. Exposure of cells to sodium nitroprusside (SNP; 0.5 to 4 mM), a NO-generating agent, induced apoptotic cell death as monitored by morphological means, gel electrophoresis, and in situ TdT-apoptosis assay. However, concomitant incubation of the cells with DB-cAMP markedly inhibited SNP-induced apoptotic cell death in a dose-dependent manner. Similar results were obtained with other commonly used cAMP analogs such as CPT-cAMP and 8-C1-cAMP and the intracellular cAMP-elevating agent such as forskolin. In contrast, pretreatment of HL-60 cells with H89 or KT5720, which are known to inhibit cAMP-dependent protein kinase (PKA), abolished the protective effect of cAMP analogs and forskolin on SNP-induced apoptosis. Synergism between SNP and phorbol ester to induce apoptosis was also inhibited by prior treatment of HL-60 cells with DB-cAMP or forskolin. The effect of DB-cAMP in maintaining cell viability was not associated with the onset of G0/G1 cell cycle arrest. In addition, neither dimethyl sulfoxide nor retinoic acid (which produce granulocyte differentiation) could produce cAMP effect. Under the same conditions, DB-cAMP also inhibited NO- or NO plus phorbol ester-induced apoptosis in another transformed cell line, U-937 cells. Taken together, these findings suggest that exposure of HL-60 cells to cAMP analogs renders them more resistant to NO-induced DNA damage and further suggest the existence of specific down-modulatory mechanisms related to NO-induced apoptotic DNA fragmentation.
authors.affiliation: Department of Microbiology and Immununology, Wonkwang University School of Medicine, Iksan, Chonbuk, Korea.
authors.forename: C D
authors.initials: CD
authors.lastname: Jun
authors.forename: H O
authors.initials: HO
authors.lastname: Pae
authors.forename: J C
authors.initials: JC
authors.lastname: Yoo
authors.forename: H J
authors.initials: HJ
authors.lastname: Kwak
authors.forename: R K
authors.initials: RK
authors.lastname: Park
authors.forename: H T
authors.initials: HT
authors.lastname: Chung
mesh_terms: D017209:Apoptosis; D003994:Bucladesine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D026423:S-Nitroso-N-Acetylpenicillamine; D026422:S-Nitrosoglutathione; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D009603:Nitroso Compounds; D009599:Nitroprusside; D005576:Colforsin; D009569:Nitric Oxide; D014212:Tretinoin; D026422:S-Nitrosoglutathione; D003994:Bucladesine; D026423:S-Nitroso-N-Acetylpenicillamine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D005978:Glutathione; D010396:Penicillamine; D013755:Tetradecanoylphorbol Acetate; D004121:Dimethyl Sulfoxide