The Mechanism Of Circular RNA FAM114A2 Suppressing Progression Of Bladder Cancer By Sponging MiR-762

Objective: Bladder cancer is the most common malignant tumor in the genitourinary system,whose high morbidity and recurrence rate makes the mortality increasing steadily.Although the surgical techniques and adjuvant therapy are constantly updating and developing,the 5-year survival rate of advanced bladder cancer is still unsatisfactory.Therefore,the treatment strategies of bladder cancer remain a major health problem faced by researchers all over the world.The pathogenic factors of bladder cancer are very complicated.However the molecular mechanism of bladder cancer is still unclear.Numerous evidences have shown that circular RNA(Circ RNA)plays a key role in regulating the pathogenesis of cancer.However,the mechanism of circ RNA in the regulation of bladder cancer progression is poorly understood.In this study,we aim to provide a new direction for the treatment of bladder cancer by exploring the molecular mechanism of circ FAM114A2 in bladder cancer.Methods: The differentially expressed circ RNAs were identified from RNA-sequencing data and verified by q RT-PCR from bladder cancer tissues and cells.The most differentially expressed circ RNA was determined as a new candidate circ RNA.The expression levels of target circ RNA-related mi RNAs and m RNAs in bladder cancer tissues and cells were detected by q RT-PCR.FISH assay was used to confirm the expression location of circ RNA and mi RNA in cell.RNA pull-down assay and luciferase reporter assay were used to investigate the interactions between the specific circ RNA,mi RNA and m RNA.The effects of candidate circ RNA and mi RNA on bladder cancer cells were explored by transfecting with plasmids or relatively mimic.The capability of migration,invasion and proliferation of bladder cancer cells in vitro were investigated by wound-healing assay,transwell assay and CCK-8 assay.The expression level of protein in bladder cancer tissues and bladder cancer cells was detected by Western blot.The effect of circ RNA on the changes of bladder cancer was confirmed by animal experiments in vivo.Finally,the relationship between the malignant degree of bladder cancer and the expression of relatively target genes was analyzed from the clinicopathological information and follow-up data.Results: In the present study,we found that circ FAM114A2 was significantly down-regulated in bladder cancer tissues and cell lines,and circ FAM114A2 expression was associated with the pathological stage and histological grade of bladder cancer.In vitro,overexpression of circ FAM114A2 can notably inhibit the migration,invasion and proliferation of bladder cancer cells.After circ FAM114A2 knockdown,the progression ability of bladder cancer was correspondingly enhanced.Similarly,when mi R-762 expression is enhanced or inhibited,the migration,invasion and proliferation of bladder cancer cells are promoted or weakened accordingly.Furthermore,overexpression of circ FAM114 A can eliminate the biological effects caused by mi R-762.At the protein level,we found that the expression of Δ NP63 was negatively correlated with the expression level of mi R-762,whereas positively correlated with circ FAM114A2.In addition,overexpression of circ FAM114 A could reverse the inhibitory effect of mi R-762 on target gene Δ NP63.In vivo,we confirmed that circ FAM114A2 can effectively inhibit the growth rate of bladder cancer and increase the expression of Δ NP63 in tumor tissue.Mechanistically,we found that circ FAM114A2 and mi R-762 were co-located in the cytoplasm.Circ FAM114A2 could directly interact with mi R-762,and subsequently act as a mi RNA sponge to disturb the expression of the mi R-762 target gene ?NP63,thus suppressed the progression of bladder cancer.Conclusions: circ FAM114A2 acts as a competitive endogenous RNA(ce RNA)of mi R-762 to regulate the expression of ? NP63,thus inhibiting the progression of bladder cancer via the circ FAM114A2 / mi R-762 / ? NP63 axis.