title: Role of bivalent cations and choline in ATP-induced apoptosis of human lymphocytes with P2Z receptors.
abstract: The role of bivalent cations and choline in ATP-induced apoptosis via P2Z purinoceptor was investigated in human leukemic lymphocytes. In vitro exposure of leukemic lymphocytes with P2Z receptors to 1 mmol/L ATP or 0.1 mmol/L benzoylbenzoic ATP (BzATP) for 8 h in the presence of choline, 1 mmol/L Mg2+ or other bivalent cations, and ATP-induced DNA breaks, associated with apoptosis were quantified by TdT assay. We observed that (1) Extracellular Mg2+ or Ca2+ stimulated ATP-induced DNA fragmentation in a dose-dependent manner, and the compatible evidence was provided by the inhibition of ATP-induced DNA fragmentation in the present of EGTA or EDTA; (2) ATP-induced DNA fragmentation was completely inhibited by 1 mmol/L Zn2+; (3) ATP-induced DNA breaks were not affected by Ba2+, Sr2+, Co2+ when they were substituted for extracellular Mg2+ or Ca2+; (4) Choline, an inhibitor of phospholipase D (PLD) stimulated by ATP through P2Z receptor in human lymphocytes, was also a partial inhibitor of ATP-induced DNA fragmentation, and the results were confirmed by flow cytometric analysis (FCA); (5) ATP-induced DNA fragmentation was completely obliterated when the temperature was lower than 10 degrees C. These results suggest that the endonuclease and PLD may be involved in ATP-induced apoptosis in human lymphocytes via P2Z receptor.
authors.affiliation: Department of Laboratory Medicine, First University Hospital, West China University of Medical Sciences, Chengdu 610041.
authors.forename: P
authors.initials: P
authors.lastname: Liming
authors.forename: J S
authors.initials: JS
authors.lastname: Wiley
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D002794:Choline / Q000494:pharmacology*; D053938:DNA Fragmentation / Q000187:drug effects; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology* / Q000503:physiopathology; D008274:Magnesium / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D058486:Receptors, Purinergic P2X7; D014407:Tumor Cells, Cultured
chemical_list: D002413:Cations, Divalent; C546468:P2RX7 protein, human; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; D008274:Magnesium; D002794:Choline; D002118:Calcium