Liquid biopsy identifies tumor-derived mir-302/367 cluster as a macrophage-reprogramming axis sustaining immune cold prostate cancer

Abstract Background Despite extensive clinical investigation, immunotherapy has failed to demonstrate consistent clinical benefit in prostate cancer (PCa), largely due to the development of an immunologically cold tumor microenvironment that resists immunotherapeutic strategies. However, the mechanisms through which systemic signals precondition tumor-associated macrophages to shape immune suppression remain poorly understood. Methods To address this, peripheral blood immune cells patients undergoing diagnostic workup for suspected PCa were analyzed, and plasma-derived extracellular vesicles were isolated from liquid biopsy samples for functional studies. Peripheral blood monocytes were isolated and differentiated ex vivo into macrophages. Results Patients with PCa harbour macrophages skewed away from pro-inflammatory M1-like features toward an M2-like immunoregulatory state, and this shift correlated with histological grade. The collapse of inflammatory cytokine production and antigen-presenting traits was accompanied by high levels of the miR-302/367 cluster in ex vivo differentiated patient-derived macrophages. Inhibition of miR-302a-5p and miR-367-3p restored M1-like phenotype across all grades, while sparing macrophages from biopsy-negative controls. Moreover, PCa cells released extracellular vesicles enriched in these microRNAs imprinting an M2-like programme onto monocyte-derived macrophages, whereas microRNA-depleted vesicles promoted M1-like polarization. Plasma-derived vesicles from PCa patients recapitulated this scenario, supporting the possible clinical relevance of this axis. Conclusions Collectively, these data identify a tumor-derived EV-miR-302/367 axis associated with macrophage reprogramming in PCa and support its role as a functional regulator of systemic myeloid conditioning.