Roles And Mechanisms Of BCAT1 In Renal Cell Carcinoma Progression

[Objective]The enzyme,Branched-chain amino transferase 1(BCAT1),is a subtype of branched-chain amino transferase located within the cytoplasm of cells.Its abnormal expression has been discovered in various tumors;however,its effects on the occurrence and development of renal cell carcinoma(RCC)remain unclear.Therefore,we aim to investigate the roles and mechanisms of BCAT1 in renal cell carcinoma.[Methods]We obtained single-cell transcriptome sequencing data of kidney renal clear cell carcinoma(KIRC)from the GSE159115 dataset downloaded from TISCH2 and performed analysis.After screening,we investigated the expression,gene mutations,prognosis,and tumor immune microenvironment of BCAT1 in KIRC through databases such as TCGA-GTEx,with BCAT1 as the target gene.Kyoto Encyclopedia of Genes and Genomes(KEGG),gene ontology(GO),single-cell gene set variation analysis(scGSVA)and gene set enrichment analysis(GSEA)were used to explore the potential functions and mechanisms of BCAT1.We utilized immunohistochemistry staining to detect the expression of BCAT1 in clinical tissue samples.We also constructed and screened stable overexpressing and knocked-down cell lines of BCAT1 for Western Blot,qRT-PCR,and phenotypic experiments.[Results]In this study,we discovered that BCAT1 is highly expressed in KIRC and is associated with disease prognosis and the tumor immune microenvironment.Analysis using the cBioPortal online tool showed that patients with BCAT1 mutations had shorter overall survival(OS)and disease-free survival(DFS).Using the Kaplan-Meier method,we found that patients with high BCAT1 expression had shorter OS,progression-free interval(PFI),and disease-specific survival(DSS)compared to those with low expression.Gene set enrichment analysis(GSEA)revealed that BCAT1 is significantly enriched in epithelial-mesenchymal transition(EMT).Immunohistochemistry staining reveals that BCAT1 is expressed higher in renal cell carcinoma compared to para-carcinoma tissues in clinical tissue samples.In vitro cell experiments demonstrated that BCAT1 may promote EMT and affect invasion and migration in KIRC cells.We constructed a protein-protein interaction(PPI)network to speculate on proteins that may bind with BCAT1.Single-sample gene set enrichment analysis(ssGSEA)revealed the immune infiltration environment of BCAT1 in KIRC.Epigenetic analysis showed that low methylation of the BCAT1 promoter region in KIRC may promote disease progression by enhancing BCAT1 expression.[Conclusion]This study comprehensively applied various technological approaches,such as bioinformatics prediction analysis and molecular biology validation.to successfully screen and identify a key cancer gene.BCAT1,in renal cell carcinoma for the first time.BCAT1 is closely associated with the prognosis and clinical features of KIRC patients and may serve as a novel biomarker,providing a new target for the treatment of renal cell carcinoma.