Mediation of gamma-hexachlorocyclohexane-induced DNA fragmentation in HL-60 cells through intracellular Ca2+ release pathway.
The cytotoxicity of gamma-hexachlorcyclohexane (gamma-HCC) was evaluated in HL-60 cells. Gamma-HCC dose-dependently induced cytotoxicity of HL-60 with an IC50 value of 60+/-5 microM. The gamma-HCC treated cells showed some characteristic changes of apoptosis, including blebbing of the membrane, condensation of the nuclear chromatin, vacuolation of cytoplasm and internucleosomal DNA fragmentation. Gamma-HCC induced DNA fragmentation of HL-60 cells in a dose-, time- and Ca2+-dependent manner. The DNA fragmentation induced was inhibited by intracellular Ca2+ chelator, calmodulin antagonist and Ca2+ sensitive endonuclease inhibitor. Gamma-HCC caused a steady increase in the cytosolic free Ca+ concentration due to release from intracellular stores. Neither the DNA fragmentation nor the increase of intracellular Ca2+ induced by gamma-HCC was inhibited by the removal of extracellular Ca2+. These data suggested that the cytotoxicity of gamma-HCC in HL-60 cells is mediated by the increase of intracellular Ca2+ concentration and the activation of Ca2+-dependent endonuclease, which triggers apoptosis in a Ca2+ and calmodulin-dependent manner.
Institute of Toxicology, College of Medicine, National Taiwan University, Taipei.
J J
JJ
Kang
I L
IL
Chen
H F
HF
Yen-Yang
D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D002273:Carcinogens / Q000633:toxicity*; D002614:Chelating Agents / Q000494:pharmacology; D002843:Chromatin / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005434:Flow Cytometry; D005452:Fluoresceins; D018922:HL-60 Cells / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D001556:Hexachlorocyclohexane / Q000633:toxicity*; D006801:Humans; D007306:Insecticides / Q000633:toxicity*
D002147:Calmodulin; D002273:Carcinogens; D002614:Chelating Agents; D002843:Chromatin; D005452:Fluoresceins; D007306:Insecticides; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C029569:diacetyldichlorofluorescein; D004533:Egtazic Acid; D001556:Hexachlorocyclohexane; D002118:Calcium