Augmenting Anti-Tumor Immunity Using Radiation in the Setting of DNA Repair Defects

尽管PARP抑制剂已被批准用于治疗晚期BRCA突变乳腺癌，但进展- 无Sion存活时间仍然很短，只有7个月。这是一个严重的问题，因为一旦PARP 抑制剂失效，全身治疗选择所剩无几，这种疾病无法治愈，导致需要 替代治疗策略。增强肿瘤免疫反应的一种策略是放射治疗(RT)， 它通过释放抗原和免疫刺激来刺激先天性和获得性免疫反应- 保守党的调解人。然而，人们对RT引发免疫应答的物理机制知之甚少。 刺激信号以及如何在DNA损伤和DNA修复缺陷的背景下利用这些信号。我们 建议研究免疫刺激信号是如何在RT诱导的DNA损伤的背景下被调制的。 年龄和DNA修复缺陷，特别是BRCA1突变。我们的初步数据表明BRCA1突变 与质子RT相结合，RT的一种形式，与 光子RT，增强更高水平的微核--参与周期的免疫刺激的前驱 GMP-AMP合成酶(CGAS)和干扰素基因刺激物(STIN)途径。我们假设 DNA修复缺陷与高LET RT相结合，通过cGAS- 刺痛路径。为了测试这一点，我们建议：1.确定高LET RT(质子)与低LET RT (光子)通过cGAS-STING途径影响BRCA1缺陷细胞的免疫原性。在……里面 为此，我们将确定质子是否增强cGAS-STING传感通路介导的抗肿瘤免疫。 BRCA1突变体和PARP中的MUNE信号相对于光子抑制肿瘤。2.在BRCA1中确定- 有缺陷的小鼠乳腺肿瘤模型-高LET RT(质子)与低LET RT(光子) 单独和在PARP和PDL1抑制剂的设置下的免疫原性。我们将使用同基因 带有和不带有功能性BRCA1的小鼠肿瘤模型评估质子和光子单独作用的效果 以及PARP和PD1抑制剂。我们将通过以下方法评估cGAS-STING通路的差异激活 评价微核水平和对STIN、TBK1、IRF3和干扰素-I的激活及定量炎症反应 细胞因子与放疗后肿瘤浸润性免疫细胞成分的变化成功完成这项工作 该项目将产生创新的临床前数据，直接将RT的质量和cGAS-STING的激活联系起来 介导的抗肿瘤免疫信号。我们的研究有可能将高LET RT定义为8月- 抑制侵袭性BRCA1突变肿瘤患者的免疫反应，可能还有其他肿瘤患者 有DNA修复缺陷。我们提出的工作是创新的，因为它旨在定义集群的影响 抗肿瘤免疫应答背景下BRCA1突变肿瘤高LET-RT所致DNA损伤 支持，这一发现可能会带来利用RT作为工具的独特物理特性的新机会 来激活免疫系统来对抗癌症。

Despite the approval of PARP inhibitors for the treatment of advanced BRCA-mutated breast cancer, progres- sion-free survival times are still quite short at only 7 months. This is a significant problem because once PARP inhibitors fail, few systemic treatment options remain and the disease cannot be cured, leading to the need for alternative treatment strategies. One strategy to enhance the immune response to tumors is radiotherapy (RT), which stimulates innate and adaptive immune responses through the release of antigens and immunostimula- tory mediators. However, relatively little is known about the physical mechanisms of RT that elicit immunostim- ulatory signals and how they can be harnessed in the context of DNA damage and DNA repair defects. We propose to investigate how immunostimulatory signals are modulated in the context of RT-induced DNA dam- age and DNA repair defects, particularly BRCA1 mutation. Our preliminary data indicate that BRCA1 mutation in combination with proton RT, a form of RT that induces relatively more clustered DNA lesions compared to photon RT, potentiates higher levels of micronuclei–a precursor of immunostimulation involving the cycling GMP-AMP synthase (cGAS) and stimulator of interferon (IFN) genes (STING) pathways. We hypothesize that DNA repair deficiency in combination with high-LET RT enhances an immune response through the cGAS- STING pathway. To test this we propose to: 1. Determine whether high-LET RT (protons) vs. low-LET RT (photons) influence the immunogenicity of cells with BRCA1 defects via the cGAS-STING pathway. In this aim, we will determine whether protons enhance cGAS-STING sensing pathway mediated anti-tumor im- mune signaling in BRCA1-mutant and PARP inhibited tumors relative to photons. 2. Determine in a BRCA1- defective murine mammary tumor model whether-high LET RT (protons) vs. low-LET RT (photons) in- fluence immunogenicity, alone and in the setting of PARP and PDL1 inhibitors. We will use syngeneic mouse tumor models with and without functional BRCA1 to evaluate the effect of protons vs. photons alone and with PARP and PD1 inhibitors. We will evaluate the differential activation of the cGAS-STING pathway by assessing micronuclei levels and activation of STING, TBK1, IRF3 and IFN-I and by quantifying inflammatory cytokines and alterations in tumor infiltrating immune cell components after RT. Successful completion of this project will generate innovative preclinical data to directly link the quality of RT and activation of cGAS-STING mediated anti-tumor immune signaling. Our research has the potential to define high LET RT as a way to aug- ment the immune response for patients with aggressive, BRCA1-mutated tumors and possibly for other tumors with DNA repair deficiency. Our proposed work is innovative in that it aims to define the effects of clustered DNA lesions generated by high LET RT on BRCA1 mutated tumors in the context of anti-tumor immune re- sponse, findings which may lead to new opportunities for harnessing unique physical properties of RT as a tool to activate the immune system to combat cancer.