In situ blockade of TNF-TNFR2 axis via oncolytic adenovirus improves antitumor efficacy in solid tumors.

Tumor necrosis factor (TNF) has been recognized as an immune activation factor in tumor immunotherapy. Our study demonstrated that TNF blockade markedly enhanced the antitumor efficacy of oncolytic adenovirus (AdV) therapy. To minimize systemic side effects, we engineered a recombinant oncolytic AdV encoding a TNF inhibitor (AdV-TNFi) to confine TNF blockade within the tumor microenvironment (TME). AdV-TNFi significantly improved therapeutic outcomes across various solid tumor models, including four murine and two golden hamster cancers. Immune cell profiling identified CD8⁺ T cells as the primary mediators of AdV-TNFi-induced antitumor effects, rather than CD4⁺ T or NK cells. Additionally, AdV-TNFi significantly decreased the infiltration of suppressive myeloid-derived immune cells within the TME and promoted long-term antitumor immune surveillance. Further investigation indicated that TNFR2, more than TNFR1, is pertinent to the immunosuppressive TME, with a recombinant AdV encoding anti-TNFR2 demonstrating comparable antitumor efficacy to AdV-TNFi. Moreover, AdV-TNFi enhanced the antitumor efficacy of gemcitabine and immune checkpoint blockades (ICBs), such as anti-PD-L1 and anti-TIGIT antibodies, in pancreatic carcinoma, and the anti-EGFR antibody in colon carcinoma. In conclusion, intratumoral blockade of the TNF/TNFR2 axis using AdV augments cancer immunotherapy efficacy while mitigating the risks associated with systemic TNF or TNFR2 suppression, warranting further clinical investigation.