title: Apoptosis and its modulation in human promyelocytic HL-60 cells treated with DNA topoisomerase I and II inhibitors.
abstract: Electron microscopy studies demonstrate unequivocally that the observed oligonucleosome-sized secondary DNA fragmentation in human promyelocytic HL-60 cells treated with the topoisomerase inhibitors camptothecin and teniposide is correlated with the morphological changes in cell structure typical of programmed cell death (apoptosis). Since apoptosis has been associated with potential involvement of intracellular signaling linked to the Ca2+/calmodulin and protein kinase C transduction pathways, we also investigated the effects of signaling modulators on camptothecin- and teniposide-induced secondary DNA fragmentation in HL-60 cells. Neither calcium chelators, calcium/calmodulin inhibitors (calmidazolium or cyclosporine A), protein kinase C stimulation by TPA, protein phosphatase inhibition by okadaic acid, protein kinase inhibition by staurosporine, calphostin C, genistein or H7, nor cell cycle alterations by caffeine had any detectable effect. Interestingly, most of these intracellular signaling modulators were able to induce DNA fragmentation in HL-60 cells by themselves. These results may suggest that even though modulation of these signaling pathways was unable to prevent topoisomerase inhibitor-induced apoptosis, their sole deregulations could induce apoptosis in HL-60 cells. In contrast, aphidicolin blocked camptothecin-induced secondary DNA fragmentation, indicating that replication-induced DNA damage is required for camptothecin- but not teniposide-induced secondary DNA fragmentation. Zinc, 3-aminobenzamide, and spermine also modulated both camptothecin- and teniposide-induced secondary DNA fragmentation without significant alteration of topoisomerase-mediated primary DNA strand breaks. Hence, poly(ADP-ribosyl)ation and chromatin structure may be important in modulating oligonucleosome-sized DNA fragmentation associated with apoptosis in HL-60 cells treated with topoisomerase inhibitors.
authors.affiliation: Institut du Cancer de Montréal, Québec, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Bertrand
authors.forename: E
authors.initials: E
authors.lastname: Solary
authors.forename: J
authors.initials: J
authors.lastname: Jenkins
authors.forename: Y
authors.initials: Y
authors.lastname: Pommier
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000470:Alkaloids / Q000494:pharmacology; D000634:Aminoquinolines / Q000494:pharmacology; D016590:Aphidicolin / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D001549:Benzamides / Q000494:pharmacology; D002118:Calcium / Q000037:antagonists & inhibitors / Q000502:physiology; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000502:physiology; D002166:Camptothecin / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002843:Chromatin / Q000648:ultrastructure; D016572:Cyclosporine / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects; D004533:Egtazic Acid / Q000494:pharmacology; D004988:Ethers, Cyclic / Q000494:pharmacology; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D007942:Leukemia, Experimental; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology*; D008854:Microscopy, Electron; D009281:Naphthalenes; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D010879:Piperazines / Q000494:pharmacology; D011064:Poly Adenosine Diphosphate Ribose / Q000096:biosynthesis; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011083:Polycyclic Compounds / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D013096:Spermine / Q000494:pharmacology; D019311:Staurosporine; D013713:Teniposide / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured; D015032:Zinc / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D000634:Aminoquinolines; D001549:Benzamides; D002147:Calmodulin; D002843:Chromatin; D004988:Ethers, Cyclic; D007546:Isoquinolines; D009281:Naphthalenes; D010879:Piperazines; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011083:Polycyclic Compounds; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D019319:Okadaic Acid; D011064:Poly Adenosine Diphosphate Ribose; D013096:Spermine; D016590:Aphidicolin; D004533:Egtazic Acid; D016572:Cyclosporine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C025160:3-aminobenzamide; D004247:DNA; D013713:Teniposide; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases; D019311:Staurosporine; C058819:calphostin C; D015032:Zinc; D013755:Tetradecanoylphorbol Acetate; C035739:Quin2; D002118:Calcium; D002166:Camptothecin