The Expression And Role Of The M6A Binding Protein YTHDF1 In Glioma Of Brain

Objective: Glioma is the most common primary intracranial tumour,mainly including diffuse astrocytic tumours and oligodendroglial tumours.It accounts for 40%?50% of intracranial tumours,and shows a rising trend year by year.At present,the treatment of glioma is still mainly surgical resection.The prognosis is not improved,although it is with radiotherapy,chemotherapy,immunotherapy and other postoperative means.The occurrence and development of glioma is regulated by many related genes,and it is a complex process involving multiple factors,multiple steps and multiple stages.There are over 100 modifications in RNA,in which the N6-methyladenosine(m6A)modification is considered to be the most common,abundant,and conserved post-transcriptional modification,especially in the eukaryotic message ribonucleic acid(m RNA).There is substantial evidence that m6 A modification has a significant impact on RNA production/metabolism and is involved in the pathogenesis of many diseases,including canner.YTH domain family 1 protein(YTHDF1),one of the m6 A binding protein,can promote protein synthesis through interaction with the translation mechanism.YTHDF1-mediated translation facilitates and improves the efficiency on the translation,ensuring the production of effective proteins from m6A-labeled dynamic transcripts.In recent years,there have been many studies on the m6 A modification.Previous studies have shown that YTHDF1 is associated with the poor prognosis of hepatocellular carcinoma,and plays an important role in pathogenesis and hypoxia adaptation in non-small cell lung cancer,and regulates the tumourigenicity of colorectal cancer.However,at present,there are no studies on the expression and role of the m6 A binding protein YTHDF1 in glioma.Therefore,this experiment mainly studies the relationship betweenYTHDF1 and the occurrence,development and biological characteristics of glioma through studying the expression of YTHDF1 on m RNA and protein level in human glioma tissue and culturing glioblastoma cell lines in vitro.Methods:1.The expression of YTHDF1 in glioma was screened in The Cancer Genome Atlas(TCGA)in Oncomine database and Gene Expression Omnibus database(GEO).2.The expression of YTHDF1 protein was investigated in glioma tissue and peritumoural brain tissue by immunohistochemistry.3.The expression of YTHDF1 in glioma cell line was verified by RT-PCR.4.The expression level of YTHDF1 in glioma cell line was detected by Western-blot.5.The effect of YTHDF1 on the multiplication of gliomas cells was detected by MTT assay.6.Transwell assay was used to investigate the effect of YTHDF1 on the invasion and migration of glioma cells.Results:1.The expression of YTHDF1 in glioma was significantly higher than that in normal brain tissue.We screened the expression of YTHDF1 in glioma in the TCGA library and GEO library.The result indicated that compared to normal brain tissue,YTHDF1 was highly expressed in glioma(P<0.05).2.The expression of YTHDF1 protein in glioma tissueImmunohistochemistry results showed that the positivity of YTHDF1 protein is localized in the cytoplasm of tumour cells.In 120 cases of glioma,the expression of YTHDF1 protein was high expression in 64 cases,with a high expression rate of 53.3%.In the 26 cases of the peritumoural brain tissue,the expression of YTHDF1 protein was only high expression in 3 cases,with a high expression rate of 13.0%.The expression of YTHDF1 protein in glioma was clearly higher than that in peritumoural brain tissue,with statisticallysignificant(P<0.05).The high expression rate of YTHDF1 protein was respectively 44.4%,58.3%,82.2%,25.9% and 27.8% in diffuse astrocytoma(WHO grade ?),anaplastic astrocytoma(WHO grade ?),glioblastoma(WHO grade ?),oligodendroglioma(WHO grade ?)and anaplastic oligodendroglioma(WHO grade ?).The expression of YTHDF1 protein in glioma was correlated with the age of patients,grade and histological type of glioma.The higher expression of YTHDF1 protein was in the older patients and higher WHO grade.The expression of YTHDF1 protein in diffuse astrocytic tumours was higher than that in oligodendroglial tumours,all with statistically significant(P<0.05).However,the expression was not clearly correlated with sex or tumour size(P>0.05).3.The knockdown efficiency of YTHDF1 in glioma cells.After the U87 and U251 cells were transfected with YTHDF1 Small interfering RNA(si RNA),the m RNA and protein levels of YTHDF1 was significantly decreased,compared with the control group(P<0.05).4.The effect of YTHDF1 on the multiplication of glioma cellsWhen we knocked down the expression of YTHDF1 in U87 and U251 cells,the multiplication of gliomas cells was not changed clearly,compared with the control group(P>0.05).It indicated that YTHDF1 could not effect the multiplication of gliomas cells.5.The effect of knockdown YTHDF1 on the invasion and migration of glioma cellsTranswell experimental result reminds that compared with the control group,the number of cells passing the membrane in U87 and U251 cells transfected with YTHDF1 si RNA was significantly lower(P<0.05).It indicated that after knocking down YTHDF1 in glioma cells,the invasion and migration of glioma cells can be inhibited.Conclusion:1.YTHDF1 is overexpression in glioma,and the expression of YTHDF1 is positively correlated with the age of patients and the grade of glioma.2.The expression of YTHDF1 protein in diffuse astrocytic tumours ishigher than that in oligodendroglial tumours,suggesting that the expression of YTHDF1 is correlated with the histological type of glioma.3.Knocking down YTHDF1 can inhibit the invasion and migration of glioma cells,which indicates that the YTHDF1 is closely ralated with the aggressiveness and migration of glioma.