The Study On The Role And Mechanism Of Differentially Expressed Protein PP1γ In Glioma Based On TMT Proteomics

Objective: The aim of the study is to identify differentially expressed proteins in glioma,understand the biological functions and interaction networks of the differentially expressed proteins,and screening key factors regulating the important signaling pathways.The study also focused on the role and molecular mechanism of key differentially expressed proteins in glioma,with a view to improving the prognosis of glioma patients and providing a theoretical basis for new therapeutic targets.Methods: 1)five pairs of glioblastoma(GBM)and non-tumor brain tissues were selected,and the differentially expressed proteins were screened by TMT-LC-MS/MS proteomics.GO,IPA,KEGG,PPI and GEPIA analysis were used to explore the main functions of differentially expressed proteins,the protein interaction networks,upstream regulators,the classical signal pathways and their prognostic significance.Finally,to screen out the key factors regulating important signaling pathways.2)Low grade glioma(LGG)and GBM paraffin-embedded tissue samples were selected to make tissue microarray,immunohistochemical technique was used to detect the relationship between protein phosphatase 1γ(PP1γ)expression and clinicopathological features and prognosis.Isocitrate dehydrogenase 1(IDH1)mutation was detected by Sanger sequencing,and1p19 q codeletion was detected by fluorescence in situ hybridization(FISH)in LGG,PP1γ expression in different molecular types of glioma was analyzed.3)stable and low expression cell line of PP1γ was constructed,and to observe the effects of PP1γ silencing on proliferation,apoptosis,cell cycle,invasion and migration,and the phosphorylation level of Yes-associated protein1(YAP1),the localization and expression of YAP1 in the nucleus and cytoplasm,as well as the expression of stem cell pluripotent markers Sox2,Oct4 and Nanog.The effect of PP1γ silencing on the CD133 positive rate,the ability of cell suspension ball formation and sensitivity of temozolomide(TMZ)was analyzed.Results: 1)according to TMT proteomics,a total of 2458 differentially expressed proteins were identified,including 1398 upregulated and 1060 downregulated differentially expressed proteins.Hippo/YAP1 signal pathway was significantly enriched in differentially expressed proteins.PP1γ was upregulated differentially expressed proteins and located at the key site of Hippo/YAP1 signal pathway.2)PP1γ was highly expressed in gliomas,the expression of PP1γ was correlated with WHO grade,Ki-67,YAP1 and Sox2 expression,the low expression of PP1γ was related to IDH1 mutation in LGG,and the high expression of PP1γ was an independent prognostic factor of poor OS in glioma.3)PP1γ silencing inhibited the proliferation,promote the apoptosis,blocked glioma cells in G0/G1 phase,and inhibited invasion and migration of glioma cells.PP1γsilencing increased the expression level of p-YAP1,inhibited YAP1 nuclear translocation,and decreased the expression of stem cell pluripotent markers Sox2,Oct4 and Nanog.PP1γ silencing decreased the proportion of CD133 positive cells,inhibited the ability of cell suspension ball formation,and enhanced the sensitivity of glioma cells to TMZ.Conclusions: PP1γ is a key upregulated differentially expressed protein in GBM,the high expression of PP1γ was associated with high degree of malignancy and poor prognosis of glioma,PP1γ mainly regulates the proliferation,invasion,maintenance of GSCs characteristics and TMZ sensitivity through the YAP1/Sox2 pathway.PP1γ may be a new important factor of targeted therapy in glioma.