JAK,PTPs抑制剂钙拮抗剂对As2O3引起的[Ca2+]i变化的影响

 目的　研究蛋白酪氨酸激酶 (JAK)、蛋白酪氨酸磷酸酶 (PTPs)抑制剂和Ca²⁺通道阻滞剂对As₂O₃致人脑皮层神经元和白血病细胞的胞浆 Ca²⁺]_i变化的影响。方法　Fluo-3/AM荧光探针标记胞浆游离Ca²⁺,激光共聚焦显微镜实时测定不同浓度As₂O₃干预后胞浆Ca²⁺]_i 的变化及JAK PTPs抑制剂和Ca²⁺通道阻滞剂对As₂O₃引起的胞浆Ca²⁺]_i 变化的影响。结果　As₂O₃升高胞浆Ca²⁺]_i,并被Ca²⁺通道阻滞剂不完全抑制。1μmol·L^-1的As₂O₃使NB4胞浆Ca²⁺]_i明显增高,而对神经元胞浆Ca²⁺]_i 影响不明显。JAK抑制剂genistein能浓度依赖性抑制As₂O₃触发的Ca²⁺]_i 升高。给药后 280s的总抑制率均值分别为NB4:(6.7± 2.9)%,(25.6±2.5) %和(52.2±3.5)%;皮层神经元:(7.8±3.1)%,(18.1± 2.8) %和(51.3±3.3)%。结论　As₂O₃对不同细胞的胞浆Ca²⁺]_i 升高程度不同。JAK,PTPs参与As₂O₃触发的钙池操纵性Ca²⁺内流。Ca²⁺通道阻滞剂参与了As₂O₃触发的电压门控性Ca²⁺内流。

Effects of JAK, PTPs inhibitors and calcium antagonists on [ Ca2+ ]i change caused by arsenic trioxide

OBJECTIVE To study the effects of protein-tyrosine-kinase (JAK), protein-tyrosine-phosphatase (PTPs) inhibitors and calcium antagonists on cytosolic Ca²⁺ changes in human leukemia cells and cortex neurons caused by arsenic trioxide (As₂O₃). METHODS Cytosolic Ca²⁺ were marked with Fluo-3/AM, and assayed with laser confocal microscopy in real-time after intervention by As₂O₃ of different concentrations. The effects of JAK/PTPs inhibitors and Ca²⁺ channel blockers on cytosolic Ca²⁺]_i change induced by As₂O₃ were observed. RESULTS Cytosolic Ca²⁺]_i was elevated by As₂O₃, which was partly blocked by verapamil. As₂O₃ (1.0μmol·L^-1) increased the Ca²⁺]_i of NB4, but showed no effect on that of neurons. Genistein, a kind of JAK inhibitor, dose-dependently decreased the rising of cytosolic Ca²⁺]_i caused by As₂O₃. The mean values of total inhibition rate in 280s after As₂O₃ intervention of different concentrations were (6.7±2.9)%, (25.6±2.5)% and (52.2±3.5)% in NB4 and (7.8±3.1)%, (18.1±2.8)% and (51.3±3.3)% in cortex neurons respectively. CONCLUSION The responses of various human cells to As₂O₃ were different in Ca²⁺]_i changes. JAK and PTPs participated in the signal transduction of Ca²⁺ operated Ca²⁺ influx, and the Ca²⁺ channel blocker participated in the voltage gating controlled Ca²⁺ influx triggered by As₂O₃.