Phospholipid scramblase 1 acts through the IL-6/JAK/STAT3 pathway to promote the malignant progression of glioma

Background: Phospholipid scramblase 1 (PLSCR1) is a calcium-dependent endofacial plasma-membrane protein that plays an essential role in multiple human cancers. However, little is known about its role in glioma. This study aimed to investigate PLSCR1 function in glioma, and elucidate its underlying molecular mechanisms. Methods: PLSCR1 expression in human glioma cell lines (U87MG, U251, LN229, A172 and T98G) and human astrocytes was detected by western blot and qRT-PCR. PLSCR1 was silenced using si-PLSCR1-1 and si-PLSCR1-2 in LN229 and U251 cells. PLSCR1 was overexpressed using the pcDNA-PLSCR1 plasmid in T98G cells. Colony formation, 5-ethynyl-2 '-deoxyuridine, flow cytometry and transwell assays were employed for measuring cell proliferation, apoptosis and mobility after PLSCR1 knockdown or overexpression. PLSCR1 function in glycolysis in glioma cells was determined through measuring the extracellular acidification rate, oxygen consumption rate, glucose consumption and lactate production. Besides, immunohistochemistry, western blot and qRT-PCR were utilized to assess mRNA and protein expression. Besides, the effect of PLSCR1 silencing on subcutaneous tumor was also monitored. Results: PLSCR1 expression was upregulated in glioma. The downregulation of PLSCR1 repressed the proliferation, mobility, epithelial-to-mesenchymal transition (EMT) and glycolysis; however, it facilitated apoptosis in glioma cells. Whereas, PLSCR1 upregulation had the opposite effect. Moreover, PLSCR1 promoted the activation of the IL-6/JAK/STAT3 pathway in glioma cells. Besides, IL-6 treatment significantly reversed the function of PLSCR1 silencing on cell proliferation, mobility, EMT, apoptosis and glycolysis. In a nude mouse tumor model, silencing PLSCR1 suppressed tumor growth via inactivating IL-6/JAK/STAT3 signaling. Conclusion: Our results indicated that PLSCR1 could facilitate proliferation, mobility, EMT and glycolysis, but repress apoptosis through activating IL-6/JAK/STAT3 signaling in glioma. Therefore, PLSCR1 may function as a potential therapeutic target for glioma.