With the identification of “negative immune regulation” defects in the immune system and the continuous improvement of immunotherapy, natural killer cells (NK) have received more attention, especially as tools in combined immunotherapy. Carbon ions (¹²C⁶⁺) have become the ideal radiation for combined immunotherapy due to their significant radiobiological advantages and synergistic effects. The purpose of this study was to explore the NK cell-mediated cytotoxicity pathway and related mechanisms in lung cancer induced by carbon ion irradiation. KLRK1, which specifically encodes the NKG2D receptor, was significantly correlated with the prognosis, clinical stage, functional status of NK cells, and the immune microenvironment of lung cancer, as shown by bioinformatics analysis. Based on RNA-seq data of Lewis lung cancer in C57BL/6 mice, carbon ion irradiation was found to significantly induce Klrk1 gene expression and activate the NKG2D/NKG2D-Ls pathway. The Treg inhibition pathway combined with carbon ion radiotherapy could significantly increase the infiltration and function of NK cells in the tumor microenvironment of lung cancer and prolong the survival time of C57BL/6 mice. In conclusion, carbon ions have significant radiobiological advantages, especially under conditions of combined immunotherapy. Carbon ions combined with Treg inhibitors can significantly improve the infiltration and functional status of NK cells.

随着免疫系统“负免疫调节”缺陷的识别和免疫疗法的不断改进，自然杀伤细胞（NK）受到越来越多的关注，尤其是作为联合免疫疗法的工具。碳离子（¹² C ⁶⁺）由于其显着的放射生物学优势和协同效应已成为联合免疫治疗的理想辐射。本研究旨在探讨碳离子辐照诱导肺癌中NK细胞介导的细胞毒性通路及相关机制。KLRK1生物信息学分析表明，特异性编码 NKG2D 受体的 NKG2D 与肺癌的预后、临床分期、NK 细胞的功能状态和免疫微环境显着相关。基于 C57BL/6 小鼠 Lewis 肺癌的 RNA-seq 数据，发现碳离子照射显着诱导Klrk1基因表达并激活 NKG2D/NKG2D-Ls 通路。Treg抑制通路联合碳离子放疗可显着增加NK细胞在肺癌肿瘤微环境中的浸润和功能，延长C57BL/6小鼠的存活时间。总之，碳离子具有显着的放射生物学优势，尤其是在联合免疫治疗条件下。碳离子结合Treg抑制剂可以显着改善NK细胞的浸润和功能状态。