Background Tumour-derived exosomes have recently been shown to participate in the formation and progression of different cancer processes, including tumour microenvironment remodelling, angiogenesis, invasion, metastasis, and drug resistance. However, the function and mechanism of exosome-encapsulated nucleic acids and proteins in bladder cancer remain unclear. This study aimed to investigate the effects of tumour-derived exosomes on the tumorigenesis and development of bladder cancer. Methods In this study, gene expression profiles and clinical information were collected from The Cancer Genome Atlas (TCGA) database and two independent Gene Expression Omnibus (GEO) datasets. The nucleic acids and proteins encapsulated in bladder cancer-derived exosomes were obtained from the ExoCarta database. Based on these databases, the expression patterns of exosomal mRNAs and proteins and the matched clinicopathological characteristics were analysed. Furthermore, we carried out a series of experiments to verify the relevant findings. Results A total of 7280 differentially expressed mRNAs were found in TCGA data, of which 52 mRNAs were shown to be encapsulated in bladder cancer-derived exosomes. Survival analysis based on the UALCAN database showed that among the top 10 upregulated and the top 10 downregulated exosomal genes, only the expression of KRT6B had a statistically significant effect on the survival of bladder cancer patients. Additionally, clinical correlation analysis showed that the elevated level of KRT6B was highly associated with bladder cancer stage, grade, and metastasis status. GSEA revealed that KRT6B was involved not only in epithelial–mesenchymal transition-related pathways but also in the immune response in bladder cancer. Ultimately, our experimental results were also consistent with the bioinformatic analysis. Conclusion KRT6B, which can be detected in bladder cancer-derived exosomes, plays an important role in the epithelial–mesenchymal transition and immune responses in bladder cancer. Further research will enable its potentially prognostic marker and therapeutic target for bladder cancer.

Background The response rate to immunotherapy in patients with bladder cancer (BCa) remains relatively low. Considering the stable existence and important functions in tumour metabolism, the role of circRNAs in regulating immune escape and immunotherapy sensitivity is receiving increasing attention. Methods Circular RNA (circRNA) sequencing was performed on five pairs of BCa samples, and circFAM13B (hsa_circ_0001535) was screened out because of its remarkably low expression in BCa. Further mRNA sequencing was conducted, and the association of circFAM13B with glycolysis process and CD8+ T cell activation was confirmed. The functions of circFAM13B were verified by proliferation assays, glycolysis assays, BCa cells-CD8+ T cell co-culture assays and tumorigenesis experiment among human immune reconstitution NOG mice. Bioinformatic analysis, RNA–protein pull down, mass spectrometry, RNA immunoprecipitation, luciferase reporter assay and fluorescence in situ hybridization were performed to validate the HNRNPL/circFAM13B/IGF2BP1/PKM2 cascade. Results Low expression of circFAM13B was observed in BCa, and it was positively associated with lower tumour stage and better prognosis among patients with BCa. The function of CD8+ T cells was promoted by circFAM13B, and it could attenuate the glycolysis of BCa cells and reverse the acidic tumour microenvironment (TME). The production of granzyme B and IFN-γ was improved, and the immunotherapy (PD-1 antibodies) sensitivity was facilitated by the inhibition of acidic TME. Mechanistically, circFAM13B was competitively bound to the KH3-4 domains of IGF2BP1 and subsequently reduced the binding of IGF2BP1 and PKM2 3’UTR. Thus, the stability of the PKM2 mRNA decreased, and glycolysis-induced acidic TME was inhibited. The generation of circFAM13B was explored by confirming whether heterogeneous nuclear ribonucleoprotein L (HNRNPL) could promote circFAM13B formation via pre-mRNA back-splicing. Conclusions HNRNPL-induced circFAM13B could repress immune evasion and enhance immunotherapy sensitivity by inhibiting glycolysis and acidic TME in BCa through the novel circFAM13B/IGF2BP1/PKM2 cascade. Therefore, circFAM13B can be used as a biomarker for guiding the immunotherapy among patients with BCa.

Background To investigate whether Pentafecta is suitable for bladder cancer patients receiving laparoscopic radical cystectomy (LRC). Methods From November 2013 to December 2020, muscle invasive Bladder Cancer (MIBC) and non-muscle invasive Bladder Cancer (NMIBC) patients who received LRC and urinary diversion were retrospectively analyzed. Pentafecta was defined as meeting five criteria: negative soft margin, ≥ 16 lymph nodes (LNs) removed, major complications free, urinary diversion related sequelae free and clinical recurrence free within 1 year. Analyze the achievement of five criteria and compare the overall survival (OS) of Pentafecta group with non-attainment group. Multivariable Cox’s regression was performed to evaluate the impact of Pentafecta on OS. Multivariable logistic regression was performed to explore the effect of surgical experience on Pentafecta attainment. Results A total of 340 patients were included, negative soft margin, ≥ 16 lymph nodes (LNs) removed, major complications free, urinary diversion related sequelae free and clinical recurrence free within 1 year were observed in 95.3%, 30.3%, 83.8%, 75.0% and 85.6% of patients, respectively. Pentafecta group had a significantly longer OS than the non-attainment group (P = 0.027). The group with 10–15 LNs removed and meeting the other four criteria had a similar OS to group with ≥ 16 LNs removed (Pentafecta group) (5-year OS: 67.3% vs 72.7%, P = 0.861). Pentafecta (HR = 0.33, P = 0.011), positive lymph nodes (HR = 2.08, P = 0.028) and MIBC (HR = 3.70, P < 0.001) were all significant predictors of OS in multivariable Cox’s regression. Surgical experience (OR = 1.05, P < 0.001), conduit (OR = 2.09, P = 0.047) and neobladder (OR = 2.47, P = 0.048) were all independent predictors of Pentafecta attainment in multivariable logistic regression. Conclusions Pentafecta is suitable for bladder cancer patients receiving LRC and has the potential to be a valuable tool for evaluating the quality of LRC. Based on Pentafecta analysis, removing 10 LNs instead of 16 LNs as the one of the five criteria may be more appropriate for bladder cancer patients.