Small-molecule GSDMD agonism in tumors stimulates antitumor immunity without toxicity

Gasdermin-mediated inflammatory cell death (pyroptosis) can activate protective immunity in immunologically cold tumors. Here, we performed a high-throughput screen for compounds that could activate gasdermin D (GSDMD), which is expressed widely in tumors. We identified 6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline (DMB) as a direct and selective GSDMD agonist that activates GSDMD pore formation and pyroptosis without cleaving GSDMD. In mouse tumor models, pulsed and low-level pyroptosis induced by DMB suppresses tumor growth without harming GSDMD-expressing immune cells. Protection is immune-mediated and abrogated in mice lacking lymphocytes. Vaccination with DMB-treated cancer cells protects mice from secondary tumor challenge, indicating that immunogenic cell death is induced. DMB treatment synergizes with anti-PD-1. DMB treatment does not alter circulating proinflammatory cytokine or leukocyte numbers or cause weight loss. Thus, our studies reveal a strategy that relies on a low level of tumor cell pyroptosis to induce antitumor immunity and raise the possibility of exploiting pyroptosis without causing overt toxicity. [Display omitted] •A GSDMD agonist (DMB) modifies Cys191 and causes cleavage-independent pyroptosis•DMB induces antitumor immunity, dependent on GSDMD expression in tumor, not host•Vaccination with DMB-treated tumor protects mice from tumor rechallenge•DMB synergies with checkpoint blockade therapy, reducing cold tumor growth Pyroptosis is an immunogenic cell death that can promote antitumor immunity. This study identified a small molecule agonist of GSDMD that induced GSDMD pore formation and pyroptosis without cleavage and showed that pulsed and low-level pyroptosis induction in cancer cells is a strategy for cancer immunotherapy with little toxicity.