Although T cell checkpoint inhibitors have transformed the treatment of cancer, the molecular determinants of tumor cell sensitivity to T cell–mediated killing need further elucidation. Here, we describe a mouse genome–scale CRISPR knockout screen that identifies tumor cell TNFα signaling as an important component of T cell–induced apoptosis, with NF-κB signaling and autophagy as major protective mechanisms. Knockout of individual autophagy genes sensitized tumor cells to killing by T cells that were activated via specific TCR or by a CD3 bispecific antibody. Conversely, inhibition of mTOR signaling, which results in increased autophagic activity, protected tumor cells from T cell killing. Autophagy functions at a relatively early step in the TNFα signaling pathway, limiting FADD-dependent caspase-8 activation. Genetic inactivation of tumor cell autophagy enhanced the efficacy of immune checkpoint blockade in mouse tumor models. Thus, targeting the protective autophagy pathway might sensitize tumors to T cell–engaging immunotherapies in the clinic.

尽管 T 细胞检查点抑制剂已经改变了癌症的治疗，但肿瘤细胞对 T 细胞介导的杀伤敏感性的分子决定因素需要进一步阐明。在这里，我们描述了一种小鼠基因组规模的 CRISPR 敲除筛选，该筛选将肿瘤细胞 TNFα 信号识别为 T 细胞诱导的细胞凋亡的重要组成部分，其中 NF-κB 信号传导和自噬是主要的保护机制。单个自噬基因的敲除使肿瘤细胞对通过特异性 TCR 或 CD3 双特异性抗体激活的 T 细胞的杀伤敏感。相反，抑制 mTOR 信号会导致自噬活性增加，从而保护肿瘤细胞免受 T 细胞杀伤。自噬在 TNFα 信号通路的相对早期阶段起作用，限制了依赖 FADD 的 caspase-8 激活。肿瘤细胞自噬的遗传失活增强了免疫检查点阻断在小鼠肿瘤模型中的功效。因此，靶向保护性自噬途径可能使肿瘤对临床中的 T 细胞参与免疫疗法敏感。