Prosaposin Indicates Aggressive Human Glioma And Promotes Human Glioma Cells Proliferation,Invasion And Migration In Vitro

Objective: Malignant glioma is the most common type of malignant primary brain tumors in human.Researches show that abnormal expression of Prosaposin has appeared in many cancers,including breast cancer,prostate cancer.However,the involvement of PSAP in the tumorigenesis and development of primary glioma remains unclear.Materials and Methods: Ethical approval for this study was obtained from the local trials committee of China Medical University,and informed consent has been obtained from patients.Primary tumor specimens were obtained from 100 patients who were diagnosed with brain glioma and underwent complete resection in the First Affiliated Hospital of China Medical University between 2012 and 2017.None of the patients had received radiotherapy or chemotherapy before surgical resection.U251 and U87 cell line was used in this research.Cells were cultured in DMEM medium with 10% fetal bovine serum(FBS,Gibco,USA).The expression of Prosaposin was determined by Western blot,RT-PCR,IHC in tissue level.The effect of Prosaposin on the proliferation of U251 and U87 glioma cells was measured by MTS assay and Colony formation assay.The effect of Prosaposin on the invasion ability of U251 and U87 glioma cells was detected by cell scratches and Transwell assay.The molecular mechanisms of Prosaposin on U251 and U87 glioma cells was observed by Western blot.Result: 1.The protein expression and m RNA expression of Prosaposin were higher in high-grade gliomas compared to low-grade gliomas.2.The inhibition of Prosaposin suppressed the absorbance at 495 nm of U251 and U87 glioma cells,such as in 72 h and 96 h,and the number of colonies(50±25,60±40)decreased compared with the control group(160±35,180±25)(p<0.01).3.Cell scratch assay showed that Prosaposin can make wound healing rate of U251 cells and U87 cells(23±5,40±5)decreased compared with the control group(56±6,75±6)(P < 0.05,p<0.01).4.Transwell assay showed that Prosaposin can reduce invasive cells number of U251,U87 cells(50±25,60±40)compared with the control group(160±35,180±25)(P < 0.01).5.Western blot results showed that compared with the control group Prosaposin can decrease the expression level of p-AKT and p-GSK3β in U251 and U87 glioma cells(P < 0.05).Conclusion: Our present study reveals that the key role of PSAP in the tumorigenesis,proliferation,invasion,and migration of malignant glioma and the expression of PSAP in glioma was correlated with the tumor grade.Down-regulation of PSAP can inhibit proliferation,invasion,and migration of U251 and U87 glioma cells.In addition,the inhibition of PSAP down-regulated the expression of p-AKT and p-GSK3β in U251、U87 glioma cells.PSAP might be a valuable prognostic biomarker to predict the tumor grade and prognosis of patients,and might provide a preliminary theoretical and experimental basis for targeting PSAP in human glioma treatment.Future study will be performed to further explore the molecular mechanisms involved in these processes in order to better understand the precise oncogene functions of PSAP in glioma.