The Mechanism Of Sortilin In Pro-invasion And Pro-proliferation Of Glioblastoma Cell

Part ? study on the mechanism of Sortilin in glioblastoma invasionObjective:High aggressiveness is a hallmark of glioblastoma(GBM)and predicts poor prognosis of patients with glioblastoma.The expression level of Sortilin has been preliminarily reported to be elevated in high-grade glioma;however,the potential significance of Sortilin in glioblastoma progression has not been elucidated.In this study,we investigated the pro-invasion effect and relative mechanism of Sortilin in glioblastoma.Methods:The prognostic analysis was conducted from internet by R2 microarray platform and from TCGA dataset.we also employed Immunohistochemistry(ICH),western blot,Immunofluorescence(IF),wound-healing,Matrigel transwell assays,glioblastomatransplantation and MRI detection in this study.Results:1.Increased levels of Sortilin were noted in the mesenchymal subtype of glioblastoma and highly aggressive subtypes of glioblastoma tissues and cell lines.high levels of Sortilin predicted poor prognoses in patients with glioblastoma.2.Sortilin knockdown or inhibition with AF38469(an orally bioavailable inhibitor of Sortilin)significantly suppressed migration and invasion by inhibiting EMT-like mesenchymal transition in glioblastoma cell.3.Sortilin promoted cell invasion mainly via GSK-3?/?-catenin/Twist-induced EMT-like mesenchymal transition in glioblastoma cell.4.Sortilin inhibitor AF38469 could effectively repress invasion-growth of glioblastoma cell in vivo and prolong the survival time of GBM-bearing mouse.Conclusion:Our results demonstrate a critical role of Sortilin in glioblastoma invasion and EMT-like mesenchymal transition,indicating that Sortilin contributes to glioblastoma progression.These data also highlight the dramatic anti-tumor effects of AF38469 in glioblastoma,suggesting that AF38469 is a potentially powerful anti-tumor agent for Sortilin-overexpressing human glioblastoma.Part ? Study on the mechanism of Sortilin in glioblastoma proliferationObjective:Cell endocytosis has been found to play critical roles in the tumorigenesis and progression of various cancers.Sortilin was identified to regulate intracellular and extracellular protein trafficking,and Sortilin was also reported to exerts pro-growth function in several kinds of cancer.However,little is known about the effects of Sortilin on GBM.Thus,we detected the pro-proliferation effect of Sortilin and relatively mechanism in GBM.Methods:CCK-8,ed U and flow cytometry assays were used to detect cell proliferation.Immunohistochemistry and western blotting were utilized to assess Frizzled receptor subtype 6(Fzd6)expression in glioma.GBM cells were treated with a pharmacological inhibitor,si RNA or sh RNA against Sortilin to assess the effects on Fzd6.Proximal ligation assays and immunofluorescence assays were conducted to confirm the interaction of Sortilin with Fzd6 and to quantify the distribution of Fzd6 in early endosomes,lysosomes and recycling endosomes.A subcutaneous and orthotopic xenograft model demonstrated the role of Sortilin in GBM growth in vivo.Results:1.Sortilin promoted GBM cell proliferation by accelerating cell cycle progression from the G1 to S phase.2.Fzd6 was upregulated in malignant glioma and facilitated cell proliferation by enhancing G1/S phase progression.3.Sortilin strongly co-localized and interacted with Fzd6 at the cell membrane and cytoplasm,and that Sortilin positively regulated Fzd6 protein expression in GBM cell.4.Sortilin and Fzd6 underwent endocytosis in GBM cell,and Sortilin strengthened Fzd6 internalization to activate downstream signaling.5.Sortilin maintained the internalization-recycling loop of Fzd6 by promoting Fzd6 sorting into early endosomes and recycling endosomes.6.Fzd6 was trafficked to late lysosomes for degradation and termination of the Fzd6 signal when Sortilin was repressed.7.Inhibition of Sortilin strongly repressed GBM growth in subcutaneous and intracranial transplant models by regulating Fzd6 expression and cellular trafficking.Conclusions:Our findings indicate that Sortilin regulates Fzd6 trafficking and is a crucial underlying mechanism of GBM cell proliferation.Our results provide a potential therapeutic target for the management of GBM.