Intravenous injection of the oncolytic virus M1 awakens antitumor T cells and overcomes resistance to checkpoint blockade

• DOI: 10.1038/s41419-020-03285-0
• Publication Date: 2020-12-12T14:02:46Z
• Authors: Yang Liu; Jing Cai; Wenfeng Liu; Yuan Lin; Li Guo; Xincheng Liu; Zhen Qin; Cuiying Xu; Yanming Zhang; Xingwen Su; Kai Deng; Guangmei Yan; Jiankai Liang
• Keywords: Inflammation; 0303 health sciences; QH573-671; T-Lymphocytes; Immunogenic Cell Death; Dendritic Cells; CD8-Positive T-Lymphocytes; Article; B7-H1 Antigen; 3. Good health; Gene Expression Regulation, Neoplastic; Mice, Inbred C57BL; Oncolytic Viruses; 03 medical and health sciences; Drug Resistance, Neoplasm; Cell Line, Tumor; Neoplasms; Injections, Intravenous; Tumor Microenvironment; Animals; Cytology; Immune Checkpoint Inhibitors; Immunologic Memory

AbstractReversing the highly immunosuppressive tumor microenvironment (TME) is essential to achieve long-term efficacy with cancer immunotherapy. Despite the impressive clinical response to checkpoint blockade in multiple types of cancer, only a minority of patients benefit from this approach. Here, we report that the oncolytic virus M1 induces immunogenic tumor cell death and subsequently restores the ability of dendritic cells to prime antitumor T cells. Intravenous injection of M1 disrupts immune tolerance in the privileged TME, reprogramming immune-silent (cold) tumors into immune-inflamed (hot) tumors. M1 elicits potent CD8+ T cell-dependent therapeutic effects and establishes long-term antitumor immune memory in poorly immunogenic tumor models. Pretreatment with M1 sensitizes refractory tumors to subsequent checkpoint blockade by boosting T-cell recruitment and upregulating the expression of PD-L1. These findings reveal the antitumor immunological mechanism of the M1 virus and indicated that oncolytic viruses are ideal cotreatments for checkpoint blockade immunotherapy.