The role of intracellular pH in cell growth arrest induced by ATP
The role of intracellular pH in cell growth arrest induced by ATP
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DOI：
10.1152/ajpcell.00578.2003
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发表时间：
2004-12-01
影响因子：
5.5
通讯作者：
Prevarskaya, N
中科院分区：
文献类型：
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作者：
Humez, S;Monet, M;Prevarskaya, N
在这项研究中，我们研究了细胞外ATP诱导雄激素非依赖性前列腺癌细胞生长停滞的离子机制。胞外ATP可逆地诱导胞内pH(pH(I))从7.41迅速下降到7.11。抑制Ca~(2+)内流、降低胞外Ca~(2+)浓度和缓冲胞浆Ca~(2+)可抑制ATP诱导的酸化，从而证明酸化是Ca~(2+)内流的结果。我们发现，ATP诱导线粒体重摄取Ca~(2+)，并使线粒体内膜瞬间去极化。用鱼藤酮和乙酰氰基对三氟甲氧基苯肼消除线粒体的质子梯度，用钌红抑制线粒体对钙的摄取，用寡霉素抑制F0F1-ATPase后，ATP诱导的酸化作用减弱。刺激或抑制Na+/H+交换均不能诱导ATP诱导的酸化。此外，由氨预脉冲方法诱导的细胞内酸化减少了内质网中可释放的钙离子的量，通过测量thapsigargin或ATP在无钙介质中诱导的胞内钙离子的变化来评估。后一项发现揭示了pH(I)和钙离子稳态之间的相互作用，其中钙离子诱导的细胞内酸化反过来可以调节内质网释放的钙离子的量。此外，pH(I)的降低能够抑制细胞的生长。综上所述，我们的结果表明，ATP诱导的DU-145细胞酸化是线粒体功能特异性作用的结果，是导致ATP诱导生长停滞的主要机制之一。
In this study, we investigated ionic mechanisms involved in growth arrest induced by extracellular ATP in androgen-independent prostate cancer cells. Extracellular ATP reversibly induced a rapid and sustained intracellular pH (pH(i)) decrease from 7.41 to 7.11. Inhibition of Ca2+ influx, lowering extracellular Ca2+, and buffering cytoplasmic Ca2+ inhibited ATP-induced acidification, thereby demonstrating that acidification is a consequence of Ca2+ entry. We show that ATP induced reuptake of Ca2+ by the mitochondria and a transient depolarization of the inner mitochondrial membrane. ATP-induced acidification was reduced after the dissipation of the mitochondrial proton gradient by rotenone and carbonyl cyanide p-trifluoromethoxyphenylhydrazone, after inhibition of Ca2+ uptake into the mitochondria by ruthenium red, and after inhibition of the F0F1-ATPase with oligomycin. ATP-induced acidification was not induced by either stimulation of the Cl-/HCO3- exchanger or inhibition of the Na+/H+ exchanger. In addition, intracellular acidification, induced by an ammonium prepulse method, reduced the amount of releasable Ca2+ from the endoplasmic reticulum, assessed by measuring change in cytosolic Ca2+ induced by thapsigargin or ATP in a Ca2+-free medium. This latter finding reveals cross talk between pH(i) and Ca2+ homeostasis in which the Ca2+-induced intracellular acidification can in turn regulate the amount of Ca2+ that can be released from the endoplasmic reticulum. Furthermore, pH(i) decrease was capable of reducing cell growth. Taken together, our results suggest that ATP-induced acidification in DU-145 cells results from specific effect of mitochondrial function and is one of the major mechanisms leading to growth arrest induced by ATP.