Expression Characteristics Of CTSA In Bladder Urothelial Carcinoma And Its Clinical Significance

Background: Bladder cancer(BLCA)is one of the most common malignant tumors worldwide,ranking tenth in absolute incidence globally,with men sixth and women seventeenth.There are three main pathological types: adenocarcinoma,squamous cell carcinoma,and urothelial carcinoma,with urothelial carcinoma accounting for more than 90% of all BLCA cases.Currently,the main method for diagnosing bladder cancer is through cystoscopy,and the treatment is mainly surgery,supplemented by chemotherapy and immunotherapy.With the development of molecular biology technology,the occurrence and development mechanisms and treatment methods of bladder cancer have been further studied,and many oncogenes related to the occurrence and progression of bladder cancer have been discovered,which provides new ideas for the treatment of bladder cancer.Recently,Cathepsin A(CTSA)has been recognized as a key oncogenic regulator that shows carboxypeptidase,deaminase,and esterase activity.However,the association between CTSA and bladder cancer remains unclear.Objective: Cathepsin A(CTSA)is a serine protease that can protect neuraminidase proteins and β-galactosidase from lysosomal protein hydrolysis by forming multienzyme complexes.In addition,CTSA is a key enzyme involved in the degradation of lysosomal membrane protein 2a(a critical protein in the autophagy pathway).Over the past few years,CTSA has been found to be overexpressed in various types of human cancers,such as breast cancer,lung cancer,prostate cancer,colorectal cancer,and hepatocellular carcinoma.This study explored the expression of the CTSA gene in normal bladder epithelial tissue and bladder urothelial carcinoma tissue with different clinical stages and pathological grades,its relationship with age,gender,high-risk factors and different clinical and pathological stages of bladder cancer,and the possible biological processes and mechanisms in which CTSA may participate in bladder urothelial carcinoma.It provides potential biomarkers and possible drug targets for the clinical diagnosis and treatment of bladder cancer.Methodology: 39 paraffin specimens of bladder urothelial carcinoma and corresponding normal bladder urothelial tissues,along with clinical information,were collected.Immunohistochemistry was used to investigate the expression difference of CTSA protein and the correlation between its expression level and patients’ clinical information.9 fresh tissue specimens of bladder urothelial carcinoma and corresponding normal bladder urothelial tissues were collected to investigate the expression level of CTSA and other proteins including HER-2 and EGFR through Western Blot.TIMER2.0,GEO and TCGA databases were used to explore the expression,diagnostic value,prognostic value,possible functional pathways,and correlation with immune infiltration of CTSA m RNA.SPSS 26.0 software was used for the analysis of clinical experimental data,and R 3.6.3 software was used for the analysis of public database data.In the immunohistochemistry experiment,paired sample t-test was used to analyze the difference in protein expression,while Wilcoxon rank-sum test was used for the Western Blot experiment.Logistic regression was used for clinical correlation and multiple-factor Cox regression was used for survival analysis to describe the statistical relationship,and differences were considered statistically significant when P<0.05.Results: 1.Immunohistochemistry and Western Blot testing showed that the expression level of CTSA in bladder urothelial carcinoma tissues was significantly higher than that in normal tissues.2.The results of immunohistochemistry showed that the protein expression level of CTSA gene was correlated with gender,lymph node metastasis,and histological grade.3.The Western Blot results showed that the expression of CTSA protein in bladder urothelial carcinoma was significantly positively correlated with HER-2 and EGFR proteins.4.TIMER2.0 database analysis showed that CTSA m RNA was significantly upregulated in various cancers,including bladder urothelial carcinoma,compared to corresponding normal tissues(P<0.05).The analysis of the expression matrix downloaded from GEO and TCGA databases showed that the expression of CTSA m RNA in bladder urothelial carcinoma was significantly upregulated compared to normal bladder urothelial tissues(P<0.05).Logistic regression analysis of TCGA-BLCA dataset showed that the expression level of CTSA m RNA was closely related to lymph node metastasis,prognostic stage,and histological grade(P<0.05).Prognostic analysis showed that the higher expression level of CTSA m RNA was closely related to poor prognosis in patients(P<0.05),and could be used as an independent risk factor for predicting the prognosis of bladder urothelial carcinoma patients.5.Functional enrichment analysis showed that CTSA might mediate the occurrence and development of bladder urothelial carcinoma through signaling pathways such as JAKSTAT and PI3K-Akt(P<0.05).GSEA analysis showed that CTSA might be involved in the progression and migration of bladder urothelial carcinoma through mechanisms such as promoting inflammation and epithelial-mesenchymal transition.6.Immune infiltration analysis found that the expression level of CTSA mRNA was significantly positively correlated with the infiltration levels of macrophages,B cells,CD8+ T cells,and tumor-associated fibroblasts(P<0.05),and significantly negatively correlated with tumor purity(P<0.05).In addition,the expression levels of immune checkpoint inhibitors such as PDCD1,CD274,and CTLA4 were also upregulated with the increasition of the expression of CTSA m RNA(P<0.05).Conclusion: The expression level of CTSA in bladder urothelial carcinoma is significantly higher than in normal bladder urothelial tissue,and has certain value in the diagnosis of bladder cancer.CTSA is significantly positively correlated with the histological grade and lymph node metastasis of bladder urothelial carcinoma,and has the potential to independently predict poor prognosis in bladder cancer patients.CTSA may promote the occurrence and progression of bladder urothelial carcinoma through signaling pathways such as JAK-STAT,PI3K-Akt,as well as mechanisms such as inflammation and epithelialmesenchymal transition.CTSA may also affect the growth and progression of bladder urothelial carcinoma tissue by regulating the process of immune infiltration.