Enoblituzumab, an immunotherapeutic agent targeting CD276, shows both safety and efficacy in activating T cells and oligodendrocyte-like cells against various cancers. Preclinical studies and mouse models suggest that therapies targeting CD276 may outperform PD1/PD-L1 blockade. However, data from mouse models indicate a significant non-responsive population to anti-CD276 treatment, with the mechanisms of resistance still unclear. In this study, we evaluate the activity of anti-CD276 antibodies in a chemically-induced murine model of head and neck squamous cell carcinoma. Using models of induced and orthotopic carcinogenesis, we identify ITGB6 as a key gene mediating differential responses to anti-CD276 treatment. Through single-cell RNA sequencing and gene-knockout mouse models, we find that ITGB6 regulates the expression of the tumor-associated chemokine CX3CL1, which recruits and activates PF4⁺ macrophages that express high levels of CX3CR1. Inhibition of the CX3CL1-CX3CR1 axis suppresses the infiltration and secretion of CXCL16 by PF4⁺ macrophages, thereby reinvigorating cytotoxic CXCR6⁺ CD8⁺ T cells and enhancing sensitivity to anti-CD276 treatment. Further investigations demonstrate that inhibiting ITGB6 restores sensitivity to PD1 antibodies in mice resistant to anti-PD1 treatment. In summary, our research reveals a resistance mechanism associated with immune checkpoint inhibitor therapy and identifies potential targets to overcome resistance in cancer treatment.

Enoblituzumab 是一种靶向 CD276 的免疫治疗剂，在激活 T 细胞和少突胶质细胞样细胞对抗各种癌症方面显示出安全性和有效性。临床前研究和小鼠模型表明，针对 CD276 的疗法可能优于 PD1/PD-L1 阻断疗法。然而，来自小鼠模型的数据表明，大量人群对抗 CD276 治疗无反应，耐药机制仍不清楚。在这项研究中，我们评估了化学诱导的头颈鳞状细胞癌小鼠模型中抗 CD276 抗体的活性。使用诱导癌和原位癌发生模型，我们将 ITGB6 确定为介导抗 CD276 治疗差异反应的关键基因。通过单细胞RNA测序和基因敲除小鼠模型，我们发现ITGB6调节肿瘤相关趋化因子CX3CL1的表达，CX3CL1招募并激活表达高水平CX3CR1的PF4 ⁺巨噬细胞。抑制 CX3CL1-CX3CR1 轴可抑制 PF4 ⁺巨噬细胞浸润和分泌 CXCL16，从而重振细胞毒性 CXCR6 ⁺ CD8 ⁺ T 细胞并增强抗 CD276 治疗的敏感性。进一步的研究表明，抑制 ITGB6 可以恢复对 PD1 治疗耐药的小鼠对 PD1 抗体的敏感性。总之，我们的研究揭示了与免疫检查点抑制剂治疗相关的耐药机制，并确定了克服癌症治疗耐药性的潜在靶点。