P2X7 receptor-mediated apoptosis of human cervical epithelial cells.
P2X7 receptor-mediated apoptosis of human cervical epithelial cells.
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DOI：
10.1152/ajpcell.00256.2004
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发表时间：
2004-11
期刊：
影响因子：
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通讯作者：
Qifang Wang;Liqin Wang;Ying-hong Feng;Xin Li;R. Zeng;G. Gorodeski
中科院分区：
文献类型：
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作者：
Qifang Wang;Liqin Wang;Ying-hong Feng;Xin Li;R. Zeng;G. Gorodeski
正常人宫颈外上皮细胞在培养过程中会发生凋亡。将细胞移至无血清培养液可增加基线细胞凋亡率，而降低细胞外钙则可阻断基线细胞凋亡率。用ATPase apyrase处理可减少基线细胞的凋亡，提示细胞外的ATP和嘌呤能机制控制着细胞的凋亡。用ATP和P2X7受体类似物2‘-3’-O-(4-苯甲酰基苯甲酰基)腺苷5‘-三磷酸(BzATP)处理后，细胞凋亡率显著增加，且呈时间和剂量相关。ATP效应的阈值在hECEs细胞为0.5微米，在CaSki癌细胞约为1微米。BzATP的促凋亡作用与肿瘤坏死因子-α部分相加，其作用可通过降低细胞外钙和caspase-9抑制剂Leu-Glu-His-Asp-O-甲基氟甲基酮(Lehd-FMK)来减弱。BzATP处理激活了caspase-9，与肿瘤坏死因子-α相比，它对caspase-8只有轻微的影响。BzATP和TNF-α均激活caspase-3，提示BzATP主要激活线粒体的凋亡途径。HECEs和CaSki细胞都能将ATP分泌到细胞外液中，条件培养液中的平均ATP活性约为0.5微米，处于足以激活P2X7受体的范围内。在这些发现的基础上，我们提出了一种新的宫颈细胞凋亡的自分泌-旁分泌机制，即通过P2X7受体调控胞浆钙，并利用线粒体凋亡途径。
Normal human ectocervical epithelial (hECE) cells undergo apoptosis in culture. Baseline apoptosis could be increased by shifting cells to serum-free medium and blocked by lowering extracellular calcium. Treatment with the ATPase apyrase attenuated baseline apoptosis, suggesting that extracellular ATP and purinergic mechanisms control the apoptosis. Treatment with ATP and the P2X7 receptor analog 2'-3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP) increased apoptosis significantly, in a time- and dose-related manner. The threshold of ATP effect was 0.5 microM in hECE cells and approximately 1 microM in CaSki cancer cells. The apoptotic effect of BzATP was additive in part to that of tumor necrosis factor (TNF)-alpha, and it could be attenuated by lowering extracellular calcium and by treatment with the caspase-9 inhibitor Leu-Glu-His-Asp-O-methyl-fluoromethylketone (LEHD-FMK). Treatment with BzATP activated caspase-9, and, in contrast to TNF-alpha, it had only a mild effect on caspase-8. Both BzATP and TNF-alpha activated caspase-3, suggesting that BzATP activates predominantly the mitochondrial apoptotic pathway. Both hECE and CaSki cells secrete ATP into the extracellular fluid, and mean ATP activity in conditioned medium was approximately 0.5 microM, which is in the range of values that suffice to activate the P2X7 receptor. On the basis of these findings we propose a novel autocrine-paracrine mechanism of cervical cell apoptosis that operates by P2X7 receptor control of cytosolic calcium and utilizes the mitochondrial apoptotic pathway.