缺氧微环境下钙信号介导鞘氨醇激酶1促进胶质瘤细胞增殖

Sphingosine kinase 1 promotes glioma cell proliferation under hypoxia via calcium signaling

目的探讨缺氧微环境下鞘氨醇激酶1(SphK1)调控胶质瘤细胞增殖的分子机制。方法缺氧建立缺氧模型;RNA干扰技术下调SphK1的表达,分别以real-time PCR及蛋白免疫印记方法检测SphK1在mRNA及蛋白水平上的表达;CCK-8检测胶质瘤细胞增殖;流式细胞术检测细胞周期;Fluo-3/AM孵育,激光共聚焦显微镜检测细胞内Ca2+的动态变化。结果 SphK1表达下调可显著降低缺氧诱导的钙内流,并在缺氧条件下影响胶质瘤细胞增殖;钙通道激活剂OAG可减弱SphK1表达下调引起的细胞增殖抑制。结论缺氧微环境下SphK1可通过对胞内钙离子的调控影响胶质瘤的增殖。

Objective To investigate the role of sphingosine kinase 1 （SphK1） in regulating the proliferation of hypoxia-exposed glioma cells in vitro and explore the possible molecular mechanisms. Methods Human glioblastoma U87MG cells was transfected with specific small interfering RNA （siRNA） constructs targeting SphK1, and the efficiency of SphK1 knockdown was validated by real-time PCR and Western blotting. The cells transfected with SphK1 siRNA and with a negative control siRNA were then exposed to 3%oxygen or 150μmol/L CoCl2 to induce hypoxia. The cell proliferation and cell cycle changes following the exposure were evaluated with the Cell Counting Kit-8 and flow cytometry, respectively, and the intracellular Ca2＋changes were monitored using Flou-4/AM under an inverted laser scanning confocal microscope. Results SphK1 knockdown significantly reduced hypoxia-induced calcium reflux and suppressed the cell proliferation. Application of OAG, an activator of calcium channels, however, obviously enhanced the cell proliferation under hypoxia. Conclusion SphK1 promotes the proliferation of glioma cells under hypoxia via regulating calcium signaling.