嘌呤能P2z受体介导白血病细胞凋亡的研究

目的探讨嘌呤能Ｐ２ｚ受体在介导慢性淋巴细胞白血病（ＣＬＬ）细胞凋亡中的作用。方法将表达Ｐ２ｚ受体［Ｐ２ｚ（＋）］与不含Ｐ２ｚ受体［Ｐ２ｚ（－）］两组ＣＬＬ细胞分别同１．０ｍｍｏｌ／Ｌ三磷酸腺苷（ＡＴＰ）体外培养８小时,以电镜、ＤＮＡ凝胶电泳和定量ＤＮＡ３′－末端的ＴｄＴ法检测细胞凋亡;并对ＡＴＰ、ＢｚＡＴＰ、２ＭｅＳＡＴＰ、ＡＴＰ－γＳ与其他核苷的诱导及ＯｘＡＴＰ、ＫＮ－６２的抑制效应做定量研究。结果（１）Ｐ２ｚ（＋）细胞能在ＡＴＰ诱导下呈现典型的细胞凋亡形态和ＤＮＡ梯状条带;（２）不同的Ｐ２ｚ受体激活剂可通过Ｐ２ｚ受体诱导细胞凋亡并产生不同量的ＤＮＡ降解片段,诱导能力的强弱顺序是ＢｚＡＴＰ＞ＡＴＰ＞２ＭｅＳＡＴＰ,而ＡＴＰ－γＳ或其他核苷几乎无诱导能力;（３）Ｐ２ｚ受体的抑制剂Ｏｘ－ＡＴＰ和钙调节蛋白激酶抑制剂ＫＮ－６２可完全阻止诱导剂诱导的细胞凋亡的诱导。结论Ｐ２ｚ受体在介导由ＡＴＰ诱导ＣＬＬ细胞凋亡的过程中起着十分重要的作用。

Apoptosis of leukemic lymphocytes mediated by purinergic P2z receptors

OBJECTIVE: To investigate the role of purinergic P2z receptors for apoptosis of human leukemic lymphocytes induced by extracellular adenosine triphosphate (ATP). METHODS: A total of 11 B-CLL patients were studied with regard to exposure of leukemic lymphocytes with (n = 8) or without (n = 3) P2z receptors to ATP, benzoylbenzoic-ATP (BzATP), 2-methylthio-ATP (2MeSATP), adenosine-5'-gamma-thio] triphosphate (ATP-gamma S), and other nucleosides for 8 h in vitro. Apoptosis was detected by electron microscopy (EM), agarose gel electrophoresis, and quantitative assay-TdT assay. RESULTS: Apoptosis was detected only in leukemic lymphocytes with P2z receptors. Using a quantitative assay, we found that ATP-induced DNA strand breaks occur specifically with BzATP, ATP and 2MeSATP, but not for analogue ATP-gamma S 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, the Ca2+/calmodulin complex played 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. CONCLUSION: These data indicate that P2z receptors on lymphocytes play an important role in apoptosis induced by ATP in vitro.