Zakharov Sergey I, Smani Tarik, Dobrydneva Yuliya, Monje Francisco, Fichandler Craig, Blackmore Peter F, Bolotina Victoria M
Boston University School of Medicine, Boston, Massachusetts, USA.
Mol Pharmacol. 2004 Sep;66(3):702-7. doi: 10.1124/mol.66.3..
We have recently found that diethylstilbestrol (DES), a synthetic estrogen agonist, inhibits thrombin-induced Ca(2+) influx in human platelets, but it remains unclear to what extend this effect might be related to the store-operated Ca(2+) influx pathway. To study the effect of DES on store-operated channels and capacitative Ca(2+) influx, we used rat basophilic leukemia (RBL) cells, vascular smooth muscle cells (SMC), and human platelets, and recorded whole-cell Ca(2+) release-activated Ca(2+) (CRAC) currents and thapsigargin (TG)-induced capacitative Ca(2+) influx. In this study, we demonstrate that extracellular DES produces a dose-dependent and reversible inhibition of CRAC currents in RBL cells (IC(50), approximately 0.5 microM), whereas intracellular DES (25 microM) has no effect. Extracellular DES (up to 30 microM) inhibited only CRAC but did not affect a whole-cell monovalent cation current mediated by TRPM7 channels. DES effectively inhibited TG-induced capacitative Ca(2+) influx in a dose-dependent manner with an IC(50) values of approximately 0.1 microM in RBL cells, <0.1 microM in SMC, and approximately 1 microM in human platelets. It is noteworthy that trans-stilbene, a close structural analog of DES that lacks hydroxyl and ethyl groups, had no effect on CRAC current and on store-operated Ca(2+) influx. Thus, we found DES to be a very effective inhibitor of store-operated channels and Ca(2+) influx in a variety of cell types.
我们最近发现，合成雌激素激动剂己烯雌酚（DES）可抑制凝血酶诱导的人血小板Ca(2+)内流，但这种效应在多大程度上与储存-操作性Ca(2+)内流途径相关仍不清楚。为了研究DES对储存-操作性通道和容量性Ca(2+)内流的影响，我们使用了大鼠嗜碱性白血病（RBL）细胞、血管平滑肌细胞（SMC）和人血小板，并记录了全细胞Ca(2+)释放激活的Ca(2+)（CRAC）电流以及毒胡萝卜素（TG）诱导的容量性Ca(2+)内流。在本研究中，我们证明细胞外DES对RBL细胞中的CRAC电流产生剂量依赖性和可逆性抑制（IC(50)约为0.5 microM），而细胞内DES（25 microM）则无作用。细胞外DES（高达30 microM）仅抑制CRAC，但不影响由TRPM7通道介导的全细胞单价阳离子电流。DES以剂量依赖性方式有效抑制TG诱导的容量性Ca(2+)内流，在RBL细胞中的IC(50)值约为0.1 microM，在SMC中<0.1 microM，在人血小板中约为1 microM。值得注意的是，反式芪，一种缺乏羟基和乙基的DES紧密结构类似物，对CRAC电流和储存-操作性Ca(2+)内流无作用。因此，我们发现DES是多种细胞类型中储存-操作性通道和Ca(2+)内流的非常有效的抑制剂。
