Perioperative Immunotherapy in Muscle-invasive Bladder Cancer

METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation

BACKGROUND

Bladder cancer (BLCA) is a challenging malignancy with a poor prognosis, particularly in muscle-invasive cases. Despite recent advancements in immunotherapy, response rates remain suboptimal. This study investigates the role of METTL3, an m6A RNA methylation "writer," in regulating the immune microenvironment of BLCA.

METHODS

Through bioinformatics analysis, we identified METTL3 as being associated with the formation of an immunosuppressive microenvironment in BLCA and poor response to immunotherapy. Subsequently, we silenced METTL3 expression in BLCA cells using short hairpin RNA (shRNA) or inhibited its function with STM2457. The effectiveness of these interventions in remodeling the BLCA tumor microenvironment (TME) was confirmed through animal experiments and flow cytometry. Mechanistically, RNA sequencing and methylated RNA immunoprecipitation (MeRIP) sequencing revealed the molecular pathways by which METTL3 regulates the TME. This was further validated using in vitro cell co-culture, immunoprecipitation, ELISA, and RNA degradation assays. The synergistic effect of METTL3 with anti-Programmed Cell Death Protein 1 (PD-1) treatment in BLCA was confirmed in both orthotopic and ectopic BLCA animal models.

RESULTS

METTL3 was found to increase CXCL5 levels and suppress CCL5 expression in an m6A-dependent manner, leading to increased recruitment of myeloid-derived suppressor cells (MDSCs) and reduced infiltration of CD8+T cells. Silencing METTL3 or inhibiting its function restored immune cell balance and significantly enhanced the efficacy of anti-PD-1 therapy. Clinically, METTL3 overexpression correlated with poor complete response rate to immune checkpoint inhibitors (ICIs) therapy, associated with an immunosuppressive microenvironment characterized by elevated MDSC levels and reduced CD8+T cell infiltration.

CONCLUSIONS

These findings highlight METTL3 as a key regulator of the immune microenvironment in BLCA and a promising therapeutic target to improve immunotherapy outcomes. Targeting METTL3 could potentially enhance the efficacy of ICIs in patients with BLCA.

Exosomal miR-184 facilitates bladder cancer progression by targeting AKR1C3 and inducing immune escape via IRF2-CXCL10 axis

Currently, the molecular mechanisms underlying bladder cancer progression remain unclear. Immune checkpoint inhibitors (ICIs) have been used to treat bladder cancer, but their efficacy is limited. Exosomes, which play a critical role in cell communication, can alter the tumor microenvironment. Therefore, it is essential to investigate the impact of bladder cancer exosomes on the tumor microenvironment. Our research demonstrates a significant up-regulation of miR-184 in exosomes derived from bladder cancer cells. miR-184 promotes bladder cancer cell proliferation in vitro and facilitates tumor growth in mice by targeting the 3' UTR of AKR1C3 mRNA. Additionally, miR-184 targets IRF2 mRNA, reducing its transcriptional inhibition on CXCL10. This process induces the expression of CXCL10, which promotes the infiltration of CD8+ T cells into the tumor. However, these infiltrating T cells become exhausted. In summary, our study reveals that bladder cancer-derived exosomes deliver miR-184, which targets AKR1C3, contributing to bladder carcinogenesis and development. We also investigate how the IRF2-CXCL10 pathway induces T cell exhaustion and leads to immune escape. This research provides new insights into the immunotherapy of bladder cancer, highlighting potential molecular targets for more effective treatment strategies.

Comparison of prognosis after transurethral resection of bladder tumor between solitary and multiple bladder cancers

This study investigates the difference in overall survival rates after transurethral resection of bladder tumor between solitary and multiple bladder cancers, aiming to provide guidance for clinical practitioners. A retrospective analysis was conducted on 133 patients with bladder cancer who underwent transurethral resection of bladder tumor from April 2017 to October 2023, of which 112 patients had complete clinical and follow-up data. Clinical and follow-up data were collected, and the overall survival rates after surgery were compared between solitary and multiple bladder cancers. In this study, the recurrence rate after transurethral resection of bladder tumor was 23.21% (26/112), and the overall survival rate was 80.36% (90/112). The overall survival rate after transurethral resection of bladder tumor was 92.11% (35/38) in the solitary bladder cancer group and 74.32% (55/74) in the multiple bladder cancer group, with a statistically significant difference between the 2 groups (P = .025). The proportion of high-grade pathology was 7.89% (3/38) in the solitary bladder cancer group and 25.68% (19/74) in the multiple bladder cancer group after transurethral resection of bladder tumor, with a statistically significant difference between the 2 groups (P = .025). The mean tumor diameter after transurethral resection of bladder tumor was 2.76 ± 1.66 cm in the solitary bladder cancer group and 4.04 ± 3.17 cm in the multiple bladder cancer group, with a statistically significant difference between the 2 groups (P = .023). Univariate and multivariate regression analyses revealed that the number of bladder tumors is a risk factor for overall survival after bladder cancer surgery (P = .004). Multiple bladder cancers have a higher pathological grade, larger tumor diameter, and poorer prognosis after transurethral resection of bladder tumor compared to solitary bladder cancers. The number of bladder tumors is an independent risk factor for overall survival after bladder cancer surgery.

Can uric acid affect the immune microenvironment in bladder cancer? A single-center multi-omics study

Metabolic abnormalities are one of the important factors in bladder cancer (BCa) progression and microenvironmental disturbance. As an important product of purine metabolism, uric acid's (UA) role in BCa metabolism and immunotherapy remains unclear. In this study, we conducted a retrospective analysis of a cohort comprising 39 BCa patients treated with PD-1 and 169 patients who underwent radical cystectomy at Shanghai Tenth People's Hospital. Kaplan-Meier curves and Cox regression analysis showed that the prognosis of patients with high UA is worse (p = 0.007), and high UA is an independent risk factor for cancer specific survival in patients with BCa (p = 0.025). We established a hyperuricemia mouse model with BCa subcutaneous xenografts in vivo. The results revealed that the subcutaneous tumors of hyperuricemia mice had a greater weight and volume in comparison with the control group. Through flow cytometric analysis, the proportion of CD8+ and CD4+ T cells in these subcutaneous tumors was seen to decline significantly. We also evaluated the relationship of UA and BCa by muti-omic analysis. UA related genes were significantly increased in the CD8+ T cell of non-responders to immunotherapy by single-cell sequencing. An 11-gene UA related signature was constructed and the risk score negatively correlated with various immune cells and immune checkpoints. Finally, a nomogram was established using a UA related signature to forecast the survival rate of patients with BCa. Collectively, this study demonstrated that UA was an independent prognostic biomarker for BCa and was associated with worse immunotherapy response.

A novel anoikis-related gene signature identifies LYPD1 as a novel therapy target for bladder cancer

Bladder cancer (BLCA) is a malignant tumor associated with unfavorable outcomes. Studies suggest that anoikis plays a crucial role in tumor progression and cancer cell metastasis. However, its specific role in bladder cancer remains poorly understood. Our objective was to identify anoikis-related genes (ARGs) and subsequently construct a risk model to assess their potential for predicting the prognosis of bladder cancer.The transcriptome data and clinical data of BLCA patients were sourced from The Cancer Genome Atlas and GEO database. We then performed the differential expression analysis to screen differentially expressed ARGs. Subsequently, we conducted non-negative matrix factorization (NMF) clustering analysis to establish molecular subtypes based on the differentially expressed ARGs. The CIBERSORT algorithm was used to estimate the quantification of different cell infiltration in BLCA tumor microenviroment. A prognostic risk model containing 7 ARGs was established using Lasso-Cox regression analysis. The nomogram was built for predicting the survival probability of BLCA patients. To determine the drug sensitivity of each sample from the high- and low-risk groups, the R package "pRRophetic" was performed. Finally, the role of LYPD1 was explored in BLCA cell lines.We identified 90 differential expression ARGs and NMF clustering categorizated the BLCA patientss into two distinct groups (cluster A and B). Patients in cluster A had a better prognosis than those in cluster B. Then, we established a ARGs risk model including CALR, FASN, FOSL1, JUN, LYPD1, MST1R, and SATB1, which was validated in the train and test set. The results suggested overall survival rate was much higher in low risk group than high risk group. The cox regression analysis, ROC curve analysis, and nomogram collectively demonstrated that the risk model served as an independent prognostic factor. The high risk group had a higher level TME scores compared to the low risk group. Furthermore, LYPD1 was low expression in BLCA cells and overexpression of LYPD1 inhibits the prolifearation, migration and invasion.In the current study, we have identified differential expression ARGs and constructed a risk model with the promise for guiding prognostic predictions and provided a therapeutic target for patients with BLCA.

Current and Future Landscape of Perioperative Treatment for Muscle-Invasive Bladder Cancer

Cisplatin-based neoadjuvant chemotherapy followed by radical cystectomy is the current standard of care for muscle-invasive bladder cancer (MIBC). However, less than half of patients are candidates for this treatment, and 50% will develop metastatic disease. Adjuvant chemotherapy could be offered if neoadjuvant treatment has not been administered for suitable patients. It is important to reduce the risk of systemic recurrence and improve the prognosis of localized MIBC. Systemic therapy for metastatic urothelial carcinoma has evolved in recent years. Immune checkpoint inhibitors and targeted agents, such as antibody-drug conjugates or FGFR inhibitors, are new therapeutic alternatives and have shown their benefit in advanced disease. Currently, several clinical trials are investigating the role of these drugs, as monotherapy and in combination with chemotherapy, in the neoadjuvant and adjuvant settings with promising outcomes. In addition, the development of predictive biomarkers could predict responses to neoadjuvant therapies.