Cancer Cell Intrinsic Interferon-I pathway Activation by Fractionated Radiation

分段放射激活癌细胞内源性干扰素-I 通路

• 批准号: 9009692
• 负责人: Sandra Demaria
• 金额: $ 38.77万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-19 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9009692
• 关键词: 4T1; Acute; Address; Affect; Aftercare; Antigens; Antineoplastic Agents; Bone Marrow; Breast Cancer Cell; CD8B1 gene; Cancer Patient; Cancer Survivor; Cancer Vaccines; Carcinoma; Cell Death; Cells; Chimera organism; Clinic; Cyclic GMP; Cytotoxic T-Lymphocyte-Associated Protein 4; DNA; Data; Dendritic Cells; Dendritic cell activation; Development; Dose; Dose Fractionation; Epitopes; Functional disorder; Gap Junctions; Gene Activation; Generations; Genes; Hematopoietic; Human; IFNAR1 gene; Immune; Immune response; Immunocompetent; Immunologic Adjuvants; Immunosuppressive Agents; Immunotherapy; Implant; In Situ; Individual; Infiltration; Interferon Type I; Interferons; Ionizing radiation; Irradiated tumor; Knowledge; Ligands; MC38; MCF7 cell; MDA MB 231; Malignant Epithelial Cell; Mediating; Modality; Modeling; Molecular; Mus; Mutate; Mutation; Myeloid Cells; Neoplasm Metastasis; Neoplastic Epithelial Cell; Pathway interactions; Patients; Phenotype; Pre-Clinical Model; Proteins; Radiation; Radiation therapy; Regimen; Role; Signal Transduction; Staging; T cell response; T-Cell Activation; T-Lymphocyte; Testing; Therapeutic; Tumor Antigens; Tumor Immunity; Vaccinated; Vaccination; Vaccines; Virus Diseases; Wild Type Mouse; Work; advanced disease; cancer cell; cancer therapy; chemotherapy; immunogenic; improved; in vitro testing; in vivo; inhibitor/antagonist; knock-down; neoplastic cell; novel; novel strategies; overexpression; pre-clinical; public health relevance; receptor; research study; response; sensor; small hairpin RNA; success; tumor; tumor microenvironment

 DESCRIPTION (provided by applicant): Recent evidence indicates that the most powerful anti-tumor T cells recognize neoantigens derived from unique mutated proteins expressed by an individual tumor, suggesting that precision vaccination is required to induce effective anti-tumor immunity in cancer patients. Importantly, such anti-tumor T cells cause tumor regression at advanced disease stages upon therapeutic immune checkpoints blockade. We have pioneered studies exploring the use of local tumor radiotherapy (RT) as a means to generate an in situ individualized vaccine. We were the first to demonstrate in a pre-clinical model that RT sensitizes unresponsive tumors to CTLA-4 blockade by inducing T cells specific for endogenous tumor antigens. Emerging evidence by us and others suggests a similar effect of RT in the clinic. However, lack of knowledge about the mechanisms involved precludes rapid progress towards the effective use of RT as an immune adjuvant. One critical unanswered question is whether dose and fractionation affect RT ability to elicit anti-tumor immune responses. We have previously found in two mouse carcinomas that generation of an in situ vaccine synergistic with anti-CTLA-4 treatment in inducing immune-mediated regression of irradiated and synchronous non-irradiated tumors (abscopal effect) was achieved by RT given in 3 fractions of 8 Gy but not by a single 20 Gy dose, suggesting that the RT regimen employed is critical. We now have data supporting the hypothesis that carcinoma cell-intrinsic activation of type I interferon (IFN-I) pathway by RT is required to generate an in situ vaccine, suggesting that RT triggers canonical defense pathways in neoplastic epithelial cells that mimic a viral infection. Our data also indicat that fractionated (FRT) but not single dose (SDRT) radiation can accomplish this via activation of the cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) and downstream stimulator of IFN genes (STING) within the irradiated cancer cells. To test the above hypothesis several mouse and human carcinoma cells will be employed to determine which RT dose/fractionation activates cGAS/STING. Next, in vivo experiments using cancer cells with selective knockdown of cGAS or STING implanted in syngeneic immunocompetent wild type, cGAS-deficient, and STING-deficient mice will be performed to determine the role of this pathway in RT-mediated induction of anti-tumor T cells that mediate tumor regression and abscopal responses. To determine whether the effects of IFN-I produced by irradiated cancer cells are cancer cell autonomous or require signaling in host DC, IFNAR1-deficient mice will be used as tumor recipient. The relationship between cancer cell-derived IFN-I and DC recruitment to tumors will be established. Finally, we will investigate the mechanisms whereby RT activates the cGAS/STING pathway in cancer cells. Overall, data obtained will have important implications for a novel use of radiotherapy as a relatively simple and widely available modality for individualized tumor vaccination.

 描述（由申请人提供）：最近的证据表明，最强大的抗肿瘤 T 细胞可以识别源自个体肿瘤表达的独特突变蛋白的新抗原，这表明需要精准疫苗接种才能在癌症患者中诱导有效的抗肿瘤免疫力。重要的是，这种抗肿瘤 T 细胞在治疗性免疫检查点阻断后导致晚期疾病阶段的肿瘤消退。我们率先进行了探索使用局部肿瘤放射治疗（RT）作为产生原位个体化疫苗的手段的研究。我们率先在临床前模型中证明，放疗通过诱导内源性肿瘤抗原特异性 T 细胞，使无反应的肿瘤对 CTLA-4 阻断变得敏感。我们和其他人的新证据表明，放疗在临床中也有类似的效果。然而，由于缺乏对相关机制的了解，阻碍了 RT 作为免疫佐剂的有效应用的快速进展。一个尚未解答的关键问题是剂量和分次是否会影响 RT 引发抗肿瘤免疫反应的能力。我们之前在两种小鼠癌症中发现，通过分 3 次 8 Gy 剂量的放疗，而非单次 20 Gy 剂量的放疗，可以产生与抗 CTLA-4 治疗协同的原位疫苗，诱导免疫介导的放疗和同步未放疗肿瘤消退（远隔效应），这表明所采用的放疗方案至关重要。我们现在有数据支持这样的假设：RT 需要通过 RT 激活癌细胞内在的 I 型干扰素 (IFN-I) 途径来产生原位疫苗，这表明 RT 触发了模仿病毒感染的肿瘤上皮细胞中的典型防御途径。我们的数据还表明，分次（FRT）而非单剂量（SDRT）辐射可以通过激活受辐射癌细胞内的胞质 DNA 传感器环 GMP-AMP 合酶（cGAS）和下游 IFN 基因刺激剂（STING）来实现这一目标。为了检验上述假设，将使用几种小鼠和人类癌细胞来确定哪种 RT 剂量/分级激活 cGAS/STING。接下来，将使用选择性敲低 cGAS 或 STING 的癌细胞植入同基因免疫活性野生型、cGAS 缺陷型和 STING 缺陷型小鼠中进行体内实验，以确定该途径在 RT 介导的抗肿瘤 T 细胞诱导（介导肿瘤消退和远隔反应）中的作用。为了确定受辐射癌细胞产生的 IFN-I 的作用是癌细胞自主的还是需要宿主 DC 中的信号传导，将使用 IFNAR1 缺陷型小鼠作为肿瘤受体。癌细胞衍生的 IFN-I 和 DC 募集到肿瘤之间的关系将被建立。最后，我们将研究 RT 激活癌细胞中 cGAS/STING 通路的机制。总体而言，获得的数据将对放射治疗作为一种相对简单且广泛使用的个体化肿瘤疫苗接种方式的新用途产生重要影响。