Pharmacological induction of MHC-I expression in tumor cells revitalizes T cell antitumor immunity

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Abstract

Antigen presentation by major histocompatibility complex class I (MHC-I) is crucial for T cell–mediated killing, and aberrant surface MHC-I expression is tightly associated with immune evasion. To address MHC-I downregulation, we conducted a high-throughput flow cytometry screen, identifying bleomycin (BLM) as a potent inducer of cell surface MHC-I expression. BLM-induced MHC-I augmentation rendered tumor cells more susceptible to T cells in coculture assays and enhanced antitumor responses in an adoptive cellular transfer mouse model. Mechanistically, BLM remodeled the tumor immune microenvironment, inducing MHC-I expression in a manner dependent on ataxia-telangiectasia mutated/ataxia telangiectasia and Rad3-related–NF-κB. Furthermore, BLM improved T cell–dependent immunotherapeutic approaches, including bispecific antibody therapy, immune checkpoint therapy, and autologous tumor-infiltrating lymphocyte therapy. Importantly, low-dose BLM treatment in mouse models amplified the antitumor effect of immunotherapy without detectable pulmonary toxicity. In summary, our findings repurpose BLM as a potential inducer of MHC-I, enhancing its expression to improve the efficacy of T cell–based immunotherapy.

Authors

Qian Yu, Yu Dong, Xiaobo Wang, Chenxuan Su, Runkai Zhang, Wei Xu, Shuai Jiang, Yongjun Dang, Wei Jiang