Sphingosine kinase 1 promotes glioma cell proliferation under hypoxia via calcium signaling / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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 150 µmol/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 Ca(2+) changes were monitored using Flou-4/AM under an inverted laser scanning confocal microscope.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>SphK1 promotes the proliferation of glioma cells under hypoxia via regulating calcium signaling.</p>