放疗是肿瘤综合治疗的重要手段之一，其作用机制不仅包括直接通过电离辐射杀伤肿瘤细胞，还涉及对免疫微环境的调控。然而，放疗对免疫微环境的作用具有两面性：一方面，放疗通过提高肿瘤细胞的免疫原性、招募抗肿瘤的免疫细胞等方式增强抗肿瘤免疫；另一方面，放疗也可以上调免疫抑制分子、通过造成血液毒性和血管损伤等方式抑制抗肿瘤免疫。在肿瘤微环境中，CD8⁺T细胞与巨噬细胞是两类重要的免疫细胞，其功能状态可直接影响肿瘤治疗的效果。CD8⁺T细胞是抗肿瘤核心效应细胞，但在肿瘤微环境中常因持续刺激、营养缺乏等发生耗竭，导致CD8⁺T细胞的杀伤功能受损和自我更新能力降低。而巨噬细胞的极化方向（促瘤M2型或抑瘤M1型）也同样会影响抗肿瘤免疫反应。M1型巨噬细胞通过杀伤肿瘤、呈递抗原及分泌促炎因子等方式激活抗肿瘤免疫，然而在肿瘤微环境中，巨噬细胞常在多种因素的作用下向促进肿瘤的M2型极化。基于以上背景，理解放疗后免疫微环境重塑的机制，探索能够减轻CD8⁺T细胞耗竭或促进巨噬细胞M1型极化的靶点，对于提高放疗疗效具有重要意义。

第一部分：ADAR1在NSCLC放疗后免疫微环境重塑中的作用

本部分的研究重点是探讨RNA特异性腺苷脱氨酶家族成员ADAR1在NSCLC放疗后免疫微环境重塑中的功能。ADAR1通过A-to-I RNA编辑功能调控肿瘤的恶性发展，其异常高表达与肿瘤细胞的增殖、转移以及耐药性密切相关。前期研究表明，ADAR1可调控NSCLC的DNA损伤修复，从而导致肿瘤细胞的内在放疗抗性增强，但其在放疗后免疫微环境中的作用尚不清楚。本研究通过多色免疫荧光和空间转录组数据验证了ADAR1及其下游靶点CD70在NSCLC放疗患者中的临床价值，并结合体内外功能试验，系统性揭示了ADAR1对放疗后免疫微环境的影响。研究发现：（1）放疗后ADAR1及A-to-I编辑水平升高，ADAR1高表达与放疗患者的不良预后密切相关；（2）ADAR1通过CD70调控CD8⁺T细胞耗竭，从而影响放疗疗效；（3）CD70-CD27轴在放疗后被激活，影响NSCLC的放疗疗效和免疫微环境重塑；（4）ADAR1特异性结合CD70 pre-mRNA的内含子3区域，通过A-to-I编辑增强其mRNA稳定性和成熟；（5）ADAR1抑制剂8-Azaadenosine可安全有效地增强放疗疗效，并通过靶向肿瘤细胞和CD8⁺T细胞双重机制促进抗肿瘤免疫应答。

本部分研究首次阐明了ADAR1-CD70轴在放疗后CD8⁺T细胞耗竭中的作用，揭示了ADAR1通过编辑内含子区域调控CD70表达的机制，并初步探索了ADAR1-CD70作为预后标志物和联合治疗靶点的有效性和可行性。

第二部分：BCL-2抑制剂在放疗后免疫微环境重塑中的作用

本部分研究则聚焦于BCL-2抑制剂Sonrotoclax联合放疗在实体瘤治疗中的协同效应及其作用机制。Sonrotoclax作为一种新型BCL-2抑制剂，不仅能够靶向野生型BCL-2蛋白，还能克服某些突变型BCL-2导致的耐药问题。研究通过CMT167和MC38小鼠皮下移植瘤模型评估了Sonrotoclax联合放疗的抗肿瘤效果及安全性，并通过流式细胞术检测体内外联合治疗组对巨噬细胞极化的影响，最终对调控机制进行探索。研究结果提示：（1）Sonrotoclax单药治疗对肿瘤生长无显著影响，但与放疗联合后显著增强肿瘤抑制效果且未增加毒性；（2）联合治疗显著提高肿瘤微环境中M1型巨噬细胞比例；（3）联合治疗增强肿瘤细胞免疫原性，表现为诱导免疫原性细胞死亡、提高MHC I类分子表达及促进促炎细胞因子释放；（4）联合治疗通过激活NF-κB信号通路促进巨噬细胞向M1型极化。

本部分研究揭示了放疗联合Sonrotoclax在实体瘤治疗中的协同作用，其作用机制是通过增强肿瘤细胞免疫原性激活NF-κB信号通路促进巨噬细胞向M1极化。放疗与Sonrotoclaxl联合治疗在增强肿瘤控制的同时不增加毒性，具有较高的临床转化价值。

综上所述，本研究系统揭示了ADAR1-CD70轴在放疗后CD8⁺T细胞耗竭中的核心作用，以及BCL-2抑制剂与放疗协同调控巨噬细胞M1极化的独特功能，为优化肿瘤放射治疗提供了重要理论依据和协同治疗策略，也为提高患者肿瘤控制带来新希望。

Radiotherapy (RT) is a critical modality in the comprehensive treatment of cancer. Its mechanisms include not only direct tumor cell killing via ionizing radiation but also the modulation of the tumor microenvironment (TME). However, the effects of radiotherapy on the tumor immune microenvironment are dual: on one hand, it enhances anti-tumor immunity by increasing tumor cell immunogenicity and recruiting anti-tumor immune cells; on the other hand, it suppresses anti-tumor immune responses by upregulating immune-suppressive molecules and inducing blood toxicity and vascular damage. Within the tumor microenvironment, the functional state of CD8⁺ T cells and macrophages directly impacts the effectiveness of cancer treatment. CD8⁺ T cells, as the core effectors of anti-tumor immunity, often become exhausted in the tumor microenvironment due to persistent stimulation or nutrient deprivation, manifested by the high expression of inhibitory receptors, impaired cytotoxic function, and reduced self-renewal capacity. Macrophage polarization (either pro-tumor M2 or anti-tumor M1 phenotype) significantly influences immune responses. M1 macrophages activate the immune system through tumor cell killing, antigen presentation, and secretion of pro-inflammatory cytokines, whereas various factors in the TME often promote the polarization of macrophages toward the M2 phenotype. Therefore, identifying targets that can alleviate CD8⁺ T cell exhaustion or promote M1 macrophage polarization is crucial for enhancing radiotherapy efficacy.

Part I: The Role of ADAR1 in Post-Radiotherapy Immune Microenvironment Remodeling in NSCLC

This section focuses on the role of RNA-specific adenosine deaminase family member ADAR1 in remodeling the immune microenvironment after radiotherapy in non-small cell lung cancer (NSCLC). ADAR1 regulates tumor progression through A-to-I RNA editing, and its aberrant overexpression is closely related to tumor proliferation, metastasis, and chemotherapy resistance. Previous studies have shown that ADAR1 modulates NSCLC DNA damage repair, influencing intrinsic radiotherapy resistance in tumor cells, but its role in the immune microenvironment post-radiotherapy remains unclear. This study utilized multiplex immunofluorescence and spatial transcriptomics to assess the clinical value of ADAR1 and its downstream targets in NSCLC patients receiving radiotherapy. Functional in vitro and in vivo assays were performed to systematically investigate the impact of ADAR1 on the post-radiotherapy immune microenvironment. The main results were as follows: (1) ADAR1 expression increased A-to-I editing levels post-radiotherapy, correlating with poor prognosis in patients; (2) ADAR1 regulated CD70 expression, mediating CD8⁺ T cell exhaustion and thus affecting radiotherapy efficacy; (3) The CD70-CD27 axis was activated post-radiotherapy and played a role in modulating NSCLC radiotherapy outcomes and immune microenvironment remodeling; (4) ADAR1 specifically binded to the intron 3 region of CD70 pre-mRNA, enhancing its mRNA stability and maturation through A-to-I editing; (5) ADAR1 inhibitor 8-Azaadenosine can safely and effectively enhance radiotherapy efficacy, promoting anti-tumor immune responses through a dual mechanism targeting tumor cells and CD8⁺ T cells.

This study is the first to clarify the core regulatory role of the ADAR1-CD70 axis in CD8⁺ T cell exhaustion after radiotherapy, revealing the mechanism of ADAR1 regulating CD70 expression through editing its intron 3 region. It also explores the potential of ADAR1-CD70 as a prognostic marker and therapeutic target in radiotherapy.

Part II: The Role of BCL-2 Inhibitor in Post-Radiotherapy Immune Microenvironment Remodeling

This section investigates the synergistic effects of the BCL-2 inhibitor Sonrotoclax combined with radiotherapy in treating solid tumors and its underlying molecular mechanisms. Sonrotoclax, a novel BCL-2 inhibitor, targets both wild-type BCL-2 protein and mutant BCL-2 protein. The study assessed the anti-tumor effects and safety of Sonrotoclax combined with radiotherapy using CMT167 and MC38 subcutaneous tumor models in mice. Flow cytometry was used to analyze the impact of combined treatment on macrophage polarization in vitro and in vivo, followed by exploration of the underlying mechanisms. The main results were as follows: (1) Sonrotoclax monotherapy did not significantly affect tumor growth, but when combined with radiotherapy, it enhanced tumor control without increasing toxicity; (2) The combined treatment significantly increased the proportion of M1 macrophages in the TME; (3) The combination enhanced tumor cell immunogenicity, inducing immunogenic cell death, increasing MHC I molecule expression, and promoting the release of pro-inflammatory cytokines; (4) The combination activates the NF-κB signaling pathway, promoting macrophage polarization to the M1 phenotype.

This study firstly reveals the synergistic mechanism of radiotherapy combined with Sonrotoclax in solid tumor treatment. The mechanism involves enhancing tumor cell immunogenicity, activating the NF-κB signaling pathway, and promoting M1 macrophage polarization. The combination of radiotherapy and Sonrotoclax enhances tumor control without increasing toxicity, offering clinical translational value.

In summary, this research systematically unveils the central role of the ADAR1-CD70 axis in CD8⁺ T cell exhaustion post-radiotherapy and identifies a novel mechanism by which BCL-2 inhibitor combined with radiotherapy regulate M1 macrophage polarization. These findings provide important theoretical insights and novel combination therapy strategies to optimize cancer radiotherapy, offering new hope for improving patient outcomes.