A Study On The Expression Change Of Cell Tigh Junction Related Gene, Claudin-11, In Bladder Cancer

BackgroundBladder cancer is a prevalent genitourinary malignancy. Currently, the diagnosis ofbladder cancer is primarily made by cystoscopy and pathological studies. However,current pathological diagnosis has limitations in the staging of bladder cancer,especially in the diagnosis of bladder cancer in situ, thus delaying appropriatetreatment and resulting unfavorable prognosis and quality of life. Therefore, a moresensitive and non-invasive method for early diagnosis and prognosis evaluation ofbladder cancer patients is urgently needed. Claudins are tight junction proteins thatconstitute the paracellular barrier and pore and are indispensable for epithelial cells.Abnormal expression of Claudins may disrupt the integrity of tight junction inepithelial tissue, resulting in decreased intercellular adhesion and dissemination ofnutritional factors and other factors that cells need. Eventually, cells lose polarity andacquire uncontrolled growth, and then progress into tumor and metastasize.PurposeTo determine whether claudin-11is differentially expressed between bladderurothelial cancer tissue and matched adjacent normal tissue and investigate its role inthe development of bladder urothelial cancer.MethodsQuantitative real-time PCR was used to detect the expression of Claudins in32pairsof bladder cancer tissues and matched adjacent normal bladder tissues. The CpGisland sequences in promoter region of claudin-11was treated by bisulfite, and thentarget gene fragment pairs of claudin-11promoter region of the CpG island sequencesfor bisulfite treatment, and then dealt with three target gene fragments of methylation.Bisulfite Sequencing PCR (BPS) was used to determine the methylation status ofClaudin-11in10pairs of bladder cancer tissues and matched adjacent normal bladdertissues from total cystectomy patients. The bladder cancer cell line was demethylatedby5-Aza-dc, while blank control group was designed. Then the demethylation was observed over time. Finally, we discuss the expression change of claudin-11inbladder cancer and the correlation of claudin-11discussion of claudin-11geneexpression changes in bladder cancer and correlation of CpG island methylation inclaudin-11promoter region and the developent of bladder cancer.ResultsHigh expression of Claudin-1,4,7was observed in bladder cancer, and claudin-11wasdecreased expression. Comparison of claudin-11in non-muscle invasive bladdercancer and muscle invasive bladder cancer, there was insignificant in bladder cancertissues and adjacent normal bladder tissues. Claudin-11was chosen for furtherstudies.BPS showed that among the three designed fragments, the first fragment(93.1%vs82.3%, P<0.001) and the third fragment (25.5%vs18.7%, P<0.001) werestatistically higher in bladder cancer tissues than in adjacent normal tissues. Thedifference of the second fragment between the two types of tissues is statisticallyinsignificant. Expression of Claudin-11increases in demethylated bladder cancer cellline5637over time.ConclusionThe function of claudin-1,4,7in bladder cancer tissue was further verified, while wefound the silence of claudin-11was associated with the bladder cancer. However thereis inactivation with the grading and staging of bladder cancer. Promoter CpG islandmethylation of Claudin-11may decrease expression of Claudin-11in bladder cancer.Knockdown of claudin-11may promote the invasion and migration of bladder cancercells. Claudin-11may serve as a biomarker for early diagnosis and a potentialtherapeutic target of bladder cancer.