摘要
ＯｂｊｅｃｔｉｖｅＴｏｉｎｖｅｓｔｉｇａｔｅｔｈｅｒｏｌｅｏｆｐｕｒｉｎｅｒｇｉｃＰ２Ｚｒｅｃｅｐｔｏｒｓｆｏｒａｐｏｐｔｏｓｉｓｏｆｈｕｍａｎｌｅｕｋｅｍｉｃｌｙｍｐｈｏｃｙｔｅｓｍｅｄｉａｔｅｄｂｙｅｘｔｒａｃｅｌｕｌａｒａｄｅｎｏｓｉｎｅｔｒｉ...
Objective To investigate the role of purinergic P2Z receptors for apoptosis of human leukemic lymphocytes mediated by extracellular adenosine triphosphate (ATP).Methods A total of 13 B chronic lymphocytic leukemia (CLL) patients were studied. Exposure of leukemic lymphocytes with (n=8) or without (n=5) P2Z receptors to ATP, benzoylbenzoic ATP (BzATP), 2 methylthio ATP (2MeSATP), adenosine 5' triphosphate (ATP γS), and other nucleosides for 8 h in vitro. Apoptosis was detected by electron microscopy (EM), agarose gel electrophoresis, and the quantitative assay TdT assay.Results Apoptosis was detected only in leukemic lymphocytes with P2Z receptors. Using a quantitative assay, ATP induced DNA strand breaks were found to occur specifically with BzATP, ATP and 2MeSATP, but not for analogue ATP γS nor other nucleosides. Meanwhile, ATP induced DNA fragmentation was fully blocked by pretreatment with oxidized ATP (OxATP), a compound recently shown to block P2Z receptors. Also, it is shown that the Ca 2+ /calmodulin complex plays a role in the regulation of the apoptosis induced by ATP on CLL cells, because an antagonist of this complex, 1 [N, O bis (5 isoquinolinesulfonyl) N methyl L tyrosyl] 4 phenylpiperazine (KN 62) was found to inhibit the ATP induced apoptosis. Furthermore, choline, an inhibitor of phospholipase D (PLD), is first shown to partially inhibit ATP induced apoptosis.Conclusion These data indicate that P2Z receptors on lymphocytes play an important role in the apoptosis induced by ATP in vitro.
