Dual cytokine-engineered macrophages rejuvenate the tumor microenvironment and enhance anti-PD-1 therapy in renal cell carcinoma

Despite advances in PD-1 blockade therapy, the immunosuppressive tumor microenvironment (TME) limits its efficacy in renal cell carcinoma (RCC). Here, we developed dual-cytokine-engineered macrophages co-delivering IL-12 and CXCL-9 to reprogram TME and enhance anti-PD-1 responsiveness. Single-cell RNA sequencing revealed that RCC harbor abundant M2-like tumor-associated macrophages (TAMs), which correlate with T-cell exhaustion. In vitro, engineered macrophages polarized M2-like TAMs to antitumor M1 phenotypes, secreted CXCL-9 to recruit cytotoxic T cells, and released IL-12 to amplify T/NK cell activation. In vivo, intravenously administered engineered macrophages homed to tumors, reshaped the TME by increasing CD8⁺ T cells, dendritic cells, and NK cells while reducing immunosuppressive Tregs and MDSCs. This approach synergized with PD-1 blockade, resulting in a 2.5-fold greater tumor growth inhibition compared to anti-PD-1 monotherapy. This dual-cytokine macrophage platform offers a novel strategy to overcome resistance to checkpoint inhibitors in RCC by delivering cytokine and remodeling TME, with implications for clinical translation.