Zdimerova, H. | bioRxiv Science

bioRxiv2025

Targeting CXCR4-expressing TAMs in muscle-invasive bladder cancer to enhance tumor control after immunotherapy

Bladder cancer (BC) is a prevalent malignancy with poor prognosis in advanced stages. While immune checkpoint blockade has revolutionized immunotherapy, its efficacy remains limited for most advanced BC patients. The detailed characterization of BCs tumor microenvironment (TME) is a prerequisite to understand these mechanisms of resistance and to develop new therapeutic strategies. In this study, we used a genetically engineered BC mouse model resistant to anti-PD1 treatment, and BC patient samples, to investigate the evolution of tumor-associated macrophages (TAMs) during BC progression. We identified a subset of pro-tumor TAMs expressing CXCR4, predominantly found in advanced stages of BC-bearing mice and in half of muscle-invasive BC patients from the studied cohort. Interestingly, CXCR4+ TAM-rich regions were associated with CD8 T cell-excluded areas in both mice and patients. Administration of a small molecule CXCR4 inhibitor significantly reduced the number of pro-tumor TAMs within the tumor and markedly prolonged mouse survival. Incorporating this inhibitor into a tri-immunotherapy regimen further enhanced survival, highlighting the potential of targeting multiple pathways to strongly enhance anti-tumor effects and offering new hope for improving immunotherapy in advanced BC.

immunology↗

bioRxiv2020

Identification of sex differences in tumor-specific T cell infiltration in bladder tumor-bearing mice treated with BCG immunotherapy

Bladder cancer is the fourth most common cancer for men. However, women are often diagnosed with later stage disease and have poorer outcomes. Whether immune-based sex differences contribute to this discrepancy is unclear. In addition, models to investigate tumor-specific immunity in bladder cancer, in the context of tumor development or response to therapy, are lacking. To address this specific unmet need, we incorporated a commonly used model antigen, ovalbumin, into two well-established models of bladder cancer; the orthotopic MB49 cell line model and the carcinogenic BBN bladder cancer model. We tested the utility of these models to investigate tumor-specific immunity in the context of immunotherapy in both sexes. We found that BCG vaccination, prior to weekly BCG instillation does not impart an immune-specific benefit to tumor-bearing mice in the context of multiple BCG instillations. Furthermore, tumors developed in the testes in male mice, precluding the use of the MB49 model to directly investigate sex-based immune differences. In the BBN model, we observed that more tumor antigen-specific CD8+ T cells infiltrated male bladders compared to female bladders in the context of BCG immunotherapy and that these cells had the highest levels of the exhaustion marker PD-1. We propose our modified BBN model will contribute to our understanding of how tumor-specific immunity arises in bladder cancer. Additionally, the BBN bladder cancer model may help to uncover sex differences in tumor-specific immunity, which would provide valuable information for the development of new treatments or combination therapies for bladder cancer in women and men.

immunology↗