High Expression Of IGF2BP3 Promotes The Development And Progression Of Bladder Cancer By Regulating HMGB1

Objective: Bladder cancer is one of the most common malignant tumors of the urinary system.In China,the incidence of bladder cancer is increasing year by year.Once the invasion and metastasis occur,the therapeutic effect is not good.IGF2BP3,or insulin-like growth factor-2 m RNA binding protein 3,belongs to a highly conserved family of single-stranded RNA-bound cancerous fetal proteins(RBPs)and is a posttranscriptional regulator of m RNA localization,stability,and translation control.Previous studies have shown that IGF2BP3 plays an important role in the occurrence and development of a variety of tumors,and its expression level is closely related to the prognosis of tumors.However,little is known about the specific role of IGF2BP3 in bladder cancer.In this study,we investigated the oncogenic function of IGF2BP3 in bladder cancer and its potential mechanism.Methods: The bladder cancer data sets from TCGA,Array Express,Oncomine and GEO databases were analyzed by bioinformatics method to investigate the expression of IGF2BP3 in bladder cancer and its relationship with various clinical features.The factors regulating the expression of IGF2BP3 were studied by combining the TCGA m RNA expression dataset with the Copy Number dataset and the methylation dataset.In this study,three kinds of bladder cancer cell lines(5637,RT112/84,BFTC905)were selected as the basic research,and the methylation degree of IGF2BP3 promoter region in these three kinds of bladder cancer cell lines(5637,RT112/84,BFTC905)was confirmed by BSP(Bisulfite Sequencing PCR)clone Sequencing method,and the protein expression of IGF2BP3 in these three kinds of bladder cancer cells was detected by Western blot.To investigate the role of IGF2BP3 in bladder cancer,Gene Set Enrichment Analysis(GSEA)was used to analyze the Gene sets associated with IGF2BP3 expression in the bladder cancer dataset.We then constructed three pairs of lentivirus transfected bladder cancer cell lines with different IGF2BP3 expression(5637Control,5637 IGF2BP3-overexpress,RT112/84 Control,RT112/84IGF2BP3-overexpress,BFTC905 Control,and BFTC905 IGF2BP3-sh RNA).In order to detect the carcinogenic effect of IGF2BP3,CCK8 assay,cell scratch assay,Transwell assay and clone formation assay were used to detect the proliferation,chemotherapy resistance,migration and invasion ability of three different types of IGF2BP3 bladder cancer cells.In addition,western blot was used to detect the effect of IGF2BP3 on epithelial-mesenchymal transition(EMT).The potential mechanism of IGF2BP3 promoting cancer was further explored,and the relationship between IGF2BP3 and HMGB1 and its downstream signaling pathway NF-kappa B and JNK was investigated.Glycyrrhizin acid(HMGB1-specific inhibitor)was used as a drug to treat three lentiviral transfected bladder cancer cells to test whether the IGF2BP3 molecule and the HMGB1 pathway it regulates can be used as a target for bladder cancer drug therapy.Results: Based on a comprehensive analysis of clinical specimens,this study found that IGF2BP3 was highly expressed in bladder cancer,which was associated with poor histological grade,TMN stage,and poor clinical prognosis.Moreover,in bladder cancer,IGF2BP3 gene overexpression is induced by copy number variation and promoter hypomethylation.IGF2BP3 overexpression can promote the proliferation,migration,invasion and chemotherapy resistance of bladder cancer cells,and promote the epithelial-mesenchymal transition(EMT),while the silence of IGF2BP3 can eliminate the cancer-promoting effect.IGF2BP3 positively regulates HMGB1 expression and activates its downstream pathways,including NF-κB and JNK pathways.In addition,Glycyrrhizin acid,a specific inhibitor of HMGB1,reverses the cancer-promoting effects of IGF2BP3.In conclusion,our study established IGF2BP3 as an oncogene for bladder cancer tumogenesis,IGF2BP3 affects the expression of HMGB1,and the IGF2BP3-HMGB1 axis may serve as a diagnostic and prognostic marker for bladder cancer,which may provide a new target for precise treatment of bladder cancer.Conclusion: This study suggests that IGF2BP3 may be a biomarker for the prognosis of bladder cancer,and the high expression of IGF2BP3 may promote the development of bladder cancer by regulating the HMGB1 signaling pathway.