Tumor-infiltrating lymphocyte (TIL) therapy has shown promising responses in clinical trials for highly aggressive cancers such as advanced melanoma and metastatic colorectal cancer. However, TIL therapy is still limited in clinical practice due to the complex ex vivo cell preparation process. Here, we report an “in situ TIL therapy” for the treatment of solid tumors. We utilized lipid nanoparticles for the delivery of an mRNA encoding membrane-anchored anti-CD3 single-chain variable fragment (scFv) (MA-aCD3), efficiently engineering both tumor-associated macrophages (TAMs) and tumor cells following intratumoral delivery. Expression of MA-aCD3 resulted in enhanced TIL activation, proliferation, and tumor cell engagement directly within the tumor microenvironment. In B16F10 and MC38 tumor models, concurrent expression of MA-aCD3 on TAMs and tumor cells mediated by mRNA delivery resulted in significant antitumor effects via in situ polyclonal CD8⁺ TIL expansion and directed cytotoxic effector functions. In addition, combinatorial treatment of MA-aCD3-encoding mRNA and antiprogrammed cell death 1 (anti-PD-1) antibodies exhibited synergistic antitumor effects on anti-PD-1 refractory B16F10 tumors. Together, our findings suggest that in situ TIL therapy is a practical and effective mRNA-based therapeutic modality for the treatment of solid tumors.

中文翻译：

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通过局部递送编码膜锚定抗 CD3 单链可变片段的 mRNA 进行原位肿瘤浸润淋巴细胞治疗


肿瘤浸润淋巴细胞 （TIL） 疗法在晚期黑色素瘤和转移性结直肠癌等高度侵袭性癌症的临床试验中显示出有希望的反应。然而，由于离体细胞制备过程复杂，TIL 疗法在临床实践中仍然受到限制。在这里，我们报道了一种用于治疗实体瘤的 “原位 TIL 疗法”。我们利用脂质纳米颗粒递送编码膜锚定抗 CD3 单链可变片段 （scFv） （MA-aCD3） 的 mRNA，在瘤内递送后有效地改造肿瘤相关巨噬细胞 （TAM） 和肿瘤细胞。MA-aCD3 的表达导致 TIL 活化、增殖和肿瘤细胞直接在肿瘤微环境中参与增强。在 B16F10 和 MC38 肿瘤模型中，MA-aCD3 在 mRNA 递送介导的 TAMs 和肿瘤细胞上同时表达，通过原位多克隆 CD8⁺ TIL 扩增和定向细胞毒性效应器功能产生显着的抗肿瘤作用。此外，编码 MA-aCD3 的 mRNA 和抗程序性细胞死亡 1 （抗 PD-1） 抗体的联合治疗对抗 PD-1 难治性 B16F10 肿瘤表现出协同抗肿瘤作用。总之，我们的研究结果表明，原位 TIL 疗法是一种实用且有效的基于 mRNA 的治疗实体瘤的治疗方式。