Circular RNAs (circRNAs) play critical roles in different diseases. Exosomes are important intermediates of intercellular communication. While both have been widely reported in cancers, exosome-derived circRNAs are rarely studied. In this work, we identified the differently expressed circRNAs in bladder cancer (BCa) tissue and exosomes through high-throughput sequencing. RNA pull-down, RNA immunoprecipitation, and luciferase reporter assays were used to investigate the interactions between specific circRNAs, microRNAs (miRNAs), and mRNAs. Wound-healing, Transwell, Cell Counting Kit-8 (CCK8), and colony-formation assays were used to study the biological roles in vitro. Metabolomics were used to explore the mechanism of how specific circRNAs influenced BCa cell behavior. Flow cytometry was used to study how specific circRNAs affected the function of CD8+ T cells in tumor microenvironments. We identified that exosome-derived hsa_circ_0085361 (circTRPS1) was correlated with aggressive phenotypes of BCa cells via sponging miR-141-3p. Metabolomics and RNA sequencing (RNA-seq) identified GLS1-mediated glutamine metabolism was involved in circTRPS1-mediated alterations. Exosomes derived from circTRPS1 knocked down BCa cells, prevented CD8+ T cells from exhaustion, and repressed the malignant phenotype of BCa cells. In conclusion, exosome-derived circTRPS1 from BCa cells can modulate the intracellular reactive oxygen species (ROS) balance and CD8+ T cell exhaustion via the circTRPS1/miR141-3p/GLS1 axis. Our work may provide a potential biomarker and therapeutic target for BCa.

We have previously demonstrated abnormal gut microbial composition in castration-resistant prostate cancer (CRPC) patients, here we revealed the mechanism of gut microbiota-derived short-chain fatty acids (SCFAs) as a mediator linking CRPC microbiota dysbiosis and prostate cancer (PCa) progression. By using transgenic TRAMP mouse model, PCa patient samples, in vitro PCa cell transwell and macrophage recruitment assays, we examined the effects of CRPC fecal microbiota transplantation (FMT) and SCFAs on PCa progression. Our results showed that FMT with CRPC patients' fecal suspension increased SCFAs-producing gut microbiotas such as Ruminococcus, Alistipes, Phascolarctobaterium in TRAMP mice, and correspondingly raised their gut SCFAs (acetate and butyrate) levels. CRPC FMT or SCFAs supplementation significantly accelerated mice's PCa progression. In vitro, SCFAs enhanced PCa cells migration and invasion by inducing TLR3-triggered autophagy that further activated NF-κB and MAPK signalings. Meanwhile, autophagy of PCa cells released higher level of chemokine CCL20 that could reprogramme the tumor microenvironment by recruiting more macrophage infiltration and simultaneously polarizing them into M2 type, which in turn further strengthened PCa cells invasiveness. Finally in a cohort of 362 PCa patients, we demonstrated that CCL20 expression in prostate tissue was positively correlated with Gleason grade, pre-operative PSA, neural/seminal vesical invasion, and was negatively correlated with post-operative biochemical recurrence-free survival. Collectively, CRPC gut microbiota-derived SCFAs promoted PCa progression via inducing cancer cell autophagy and M2 macrophage polarization. CCL20 could become a biomarker for prediction of prognosis in PCa patients. Intervention of SCFAs-producing microbiotas may be a useful strategy in manipulation of CRPC.

Background: The effective treatment and prognosis prediction of bladder cancer (BLCA) remains a medical problem. Ferroptosis is an iron-dependent form of programmed cell death. Ferroptosis is closely related to tumour occurrence and progression, but the prognostic value of ferroptosis-related genes (FRGs) in BLCA remains to be further clarified. In this study, we identified an FRG signature with potential prognostic value for patients with BLCA. Methods: The corresponding clinical data and mRNA expression profiles of BLCA patients were downloaded from The Cancer Genome Atlas (TCGA). Univariate Cox regression was used to extract FRGs related to survival time, and a Cox regression model was used to construct a multigene signature. Both principal component analysis (PCA) and single-sample gene set enrichment analysis (ssGSEA) were performed for functional annotation. Results: Clinical traits were combined with FRGs, and 15 prognosis-related FRGs were identified by Cox regression. High expression of CISD1, GCLM, CRYAB, SLC7A11, TFRC, ACACA, ZEB1, SQLE, FADS2, ABCC1, G6PD and PGD was related to poor survival in BLCA patients. Multivariate Cox regression was used to construct a prognostic model with 7 FRGs that divided patients into two risk groups. Compared with that in the low-risk group, the overall survival (OS) of patients in the high-risk group was significantly lower (P < 0.001). In multivariate regression analysis, the risk score was shown to be an independent predictor of OS (HR = 1.772, P < 0.01). Receiver operating characteristic (ROC) curve analysis verified the predictive ability of the model. In addition, the two risk groups displayed different immune statuses in ssGSEA and different distributed patterns in PCA. Conclusion: Our research suggests that a new gene model related to ferroptosis can be applied for the prognosis prediction of BLCA. Targeting FRGs may be a treatment option for BLCA.

Circular RNAs (circRNAs) drive several cellular processes including proliferation, survival, and differentiation. Here, we identified a circRNA hsa_circ_0007813, whose expression was upregulated in bladder cancer. High hsa_circ_0007813 expression was associated with larger tumor size, higher primary tumor T stage, and higher pathologic grade. Survival analysis showed that patients with high hsa_circ_0007813 expression levels had a poorer prognosis. Based on these findings from clinical tissue samples and cell lines, we assumed that hsa_circ_0007813 functioned a vital role in bladder cancer progression. Next, functional experiments revealed that knockdown of hsa_circ_0007813 inhibited proliferation, migration, and invasiveness of bladder cancer cells both in vitro and in vivo. Through extensive bioinformatic prediction and RNA pull-down assays, we identified hsa-miR-361-3p as a competing endogenous RNA of hsa_circ_0007813. Further bioinformatic studies narrowed targets to 35 possible downstream genes. We then found that knockdown of hsa_circ_0007813 led to altered cell autophagy, bringing our attention to IGF2R, one of the possible downstream genes. IGF2R was also known as cation-independent mannose-6-phosphate receptor (CI-M6PR), was discovered to participate in both autophagy and tumor biology. Regarding autophagy has a dominant role in the survival of tumor cells overcoming cellular stress and correlates with tumor progression, investigations were made to prove that hsa_circ_0007813 could regulate IGF2R expression via hsa-miR-361-3p sponging. The potential of hsa_circ_0007813 in regulating IGF2R expression explained its influence on cell behavior and clinical outcomes. Collectively, our data could offer new insight into the biology of circRNA in bladder cancer.

Tumor relapse and metastasis are the major causes of mortality associated with urothelial cancer. In the tumor microenvironment, negative regulatory molecules and various immune cell subtypes suppress antitumor immunity. The inflammatory microenvironment, associated with neutrophils and neutrophil extracellular traps (NETs), promotes tumor metastasis. However, no drugs are currently available to specifically inhibit neutrophils and NETs. In this study, we first demonstrated that icaritin (ICT), a Chinese herbal remedy that is a first-line treatment for advanced and incurable hepatocellular carcinoma, reduces NETs caused by suicidal NETosis and prevents neutrophil infiltration in the tumor microenvironment. Mechanistically, ICT binds to and inhibits the expression of PADI2 in neutrophils, thereby suppressing PADI2-mediated histone citrullination. Moreover, ICT inhibits ROS generation, suppresses the MAPK signaling pathway, and inhibits NET-induced tumor metastasis. Simultaneously, ICT inhibits tumoral PADI2-mediated histone citrullination, which consequently suppresses the transcription of neutrophil-recruiting genes such as GM-CSF and IL-6. The downregulation of IL-6 expression, in turn, forms a regulatory feedback loop through the JAK2/STAT3/IL-6 axis. Through a retrospective study of clinical samples, we found a correlation between neutrophils, NETs, UCa prognosis, and immune evasion. Combining ICT with immune checkpoint inhibitors may have synergistic effects. In summary, our study demonstrated that ICT could be a novel inhibitor of NETs and a novel UCa treatment.

Circular RNAs (circRNAs) play an important role in bladder cancer (BC). Though circRNA involvement in BC has been reported, the underlying regulatory mechanisms are unknown. In this study, we performed EdU, CCK8, colony formation and Transwell assays to establish the role of circRGNEF in BC cell migration, proliferation, and invasion. We used bioinformatics and luciferase reporter experiments to investigate the regulatory mechanism. Nude mice xenografts and live imaging were used to explore the role of circRGNEF in tumor metastasis and growth. Expression profile analysis of human circRNAs in BC revealed that circRGNEF was upregulated significantly. High circRGNEF expression was correlated with aggressive BC phenotypes. The downregulation of circRGNEF suppressed BC cell metastasis and proliferation by targeting the miR-548/KIF2C axis in vitro and in vivo; these results were verified with luciferase reporter assays. Our results show that miR-548 downregulation or KIF2C overexpression restored BC cell proliferation, migration, and invasion following silencing of circRGNEF. KIF2C overexpression reversed miR-548-induced cell invasion and migration as well as growth inhibition in vitro. In summary, the data illustrate that circRGNEF suppresses BC progression by functioning as a miR-548 sponge to enhance KIF2C expression. Therefore, circRGNEF might be a candidate BC treatment target.