| Background: Bladder cancer is the most common malignant tumor of the urinary system.Although the diagnosis and treatment of bladder cancer has been greatly improved in recent years,the clinical diagnosis of bladder cancer still depends on invasive cystoscopy biopsy.Long-noncoding RNA(lnc RNA)is a type of RNA that is more than 200 nucleotides in length and does not encode proteins,but are expressed in various forms at the RNA level(epigenetic regulation,transcriptional regulation,and post-transcriptional regulation etc.)regulate the expression of genes.Studies have found that many lnc RNAs play an important role in the occurrence and development of cancer,and may be used as new biomarkers for the early diagnosis and treatment of cancer.Objective: As a newly discovered lnc RNA,CASC9 has abnormal expression in esophageal cancer,liver cancer,gastric cancer and other cancers in recent years,but no studies have been reported in bladder cancer.Therefore,the purpose of this study is to investigate the expression level of CASC9 in bladder cancer.To explore its function and mechanism in bladder cancer,and provide new diagnostic markers and therapeutic targets for bladder cancer.Methods: Quantitative real-time PCR(q RT-PCR)was used to detect the expression of CASC9 in 49 cases of bladder cancer tissues and adjacent tissues,and the correlation between CASC9 and TNM stages and tumor invasion depth was analyzed based on clinical data.The CASC9 was also detected in the expression levels of five bladder cancer cell lines(T24,TCCSUP,UMUC3,J82 and 5637)and human normal bladder epithelial cell lines SV-HUC-1;The proliferation of bladder cancer cells was detected by CCK-8 and Ed U proliferation assay;Migration and invasion of bladder cancer cells were detected by wound healing assay and Transwell assay;Bioinformatics software was used to predict the downstream mechanism of CASC9;EMT(Epithelial-Mesenchymal Transition)chip was used to detect the expression of EMT-related genes after knockdown of CASC9;Western blot was used to detect the expression of EMT-related proteins TGF-β2,E-cadherin and N-cadherin in bladder cancer cells.Results: QRT-PCR results showed that in 49 patients with bladder cancer,79.6%(39/49)tumor samples had significantly higher CASC9 expression than the corresponding adjacent normal tissue,and the increased level of CASC9 expression in tumor tissue was positively correlated with the T stage of the tumor.Compared with T1 or T2 stage patients,the higher level of CASC9 expression in tumor tissue of high-grade(T3 or T4)stage patients,P<0.05,the difference was statistically significant;QRT-PCR results showed that CASC9 was significantly increased in five bladder cancer cell lines compared with human normal bladder epithelial cell line SV-HUC-1,and expressed highest in J82 and 5637 cell lines;CCK-8 and Ed U proliferation experiments showed that knockdown CASC9 expression significantly inhibited the proliferation of J82 and 5637 cell lines;The wound healing assay and Transwell assay showed that knockdown of CASC9 expression significantly inhibited the migration and invasion of J82 and 5637 cell lines;Bioinformatics predicted that CASC9 sponged mi R-758-3p to promote EMT of bladder cancer by up-regulating TGF-β2;Western blot showed that the expression of EMT-related proteins TGF-β2 and N-cadherin decreased and the expression of E-cadherin increased after knockdown of CASC9,indicating that the EMT transformation of bladder cancer cells was inhibited after CASC9 knockdown.Conclusions: The expression of lnc RNA CASC9 in bladder cancer tissues and cell lines is significantly increased,and it is positively correlated with the T stage of bladder cancer.The elevated expression of CASC9 can promote the proliferation,migration and invasion;CASC9 sponged mi R-758-3p to promote EMT of bladder cancer by up-regulating TGF-β2. |
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