Project 2

总结/摘要 SMARCA 4突变型NSCLC是一种流行的、侵袭性的亚群，迫切需要有效的治疗。 SMARCA 4编码BRG 1，其是SWITCH/蔗糖非发酵性（SWI/SNF）的关键ATP酶亚基。 染色质重塑复合体SMARCA 4突变存在于9-11%的NSCLC患者中， 截短，BRG 1失活突变，包括超过三分之一的这些改变。因此，SMARCA 4 是NSCLC中最常见的突变基因之一，没有靶向治疗选择。SMARCA4 突变通常与分子改变（KEAP 1和STK 11突变）重叠， 传统的治疗方法，如免疫疗法和化疗。在最近的一项研究中， 在实验室中，BRG 1缺陷增加了DNA复制应激并增强了对ATR途径的敏感性 临床前肺癌模型中的抑制。共济失调性毛细血管扩张症突变和Rad 3相关（ATR）激酶是一个新的研究领域。 细胞对复制应激反应的关键调节因子，激活DNA损伤检查点以响应 在切除DNA双链断裂或由于DNA复制缺陷而产生的单链DNA。 在这里，我们将测试这一假设，即与BRG 1缺陷相关的潜在复制应激提供了 SMARCA 4突变型肺癌的治疗机会;我们将确定有效的药物组合， ATR抑制。我们将以我们的发现为基础，通过（目标1）全面表征 复制应激和用SMARCA 4评估NSCLC临床标本中的免疫系统活化 突变，（目的2）评估SMARCA 4突变NSCLC对靶向复制应激的治疗的敏感性 缺陷，和（目的3）进行临床前研究，以评估ATR抑制的抗肿瘤作用， 与抗PD 1/PD-L1免疫疗法组合。我们将利用SMARCA 4的现有临床前模型- 突变体，BRG 1缺陷型NSCLC（在Kim Lab中产生的CRISPR产生的同基因BRG 1缺陷系， GEMM）和Hata Lab（BRG 1缺陷型患者来源的异种移植物（PDX）），以及来自Dr. Dagogo-Jack和Cheng评价候选药物合理组合的抗肿瘤活性，以支持 临床试验的未来发展。总的来说，这项拨款中提出的研究旨在促进对患者的护理 SMARCA 4突变型NSCLC，探索一种新的、有前途的方法， BRG 1缺陷型。我们设想这项研究中提出的工作将为临床试验探索 新的联合治疗方法（ATR抑制加免疫治疗或吉西他滨）治疗 BRG 1缺陷型NSCLC，可能为未来的批准铺平道路。

Summary/Abstract SMARCA4-mutant NSCLC represents a prevalent, aggressive subset in urgent need of effective therapies. SMARCA4 encodes BRG1, a key ATPase subunit of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex. SMARCA4 mutations are present in 9-11% of patients with NSCLC, with truncating, BRG1-inactivating mutations comprising greater than one-third of these alterations. Thus, SMARCA4 is one of the most frequently mutated genes in NSCLC that has no targeted treatment option. SMARCA4 mutations often overlap with molecular alterations (KEAP1 and STK11 mutations) that decrease sensitivity to traditional therapeutic approaches such as immunotherapy and chemotherapy. In a recent study from the Kim laboratory, BRG1 deficiency increased DNA replicative stress and enhanced sensitivity to ATR pathway inhibition in preclinical lung cancer models. Ataxia telangectasia mutated and Rad3-related (ATR) kinase is a key regulator of cellular response to replication stress that activates the DNA damage checkpoint in response to single strand DNA created during the resection of DNA double-strand breaks or due to defects in DNA replication. Here, we will test the hypothesis that the underlying replication stress associated with BRG1 deficiency provides a therapeutic opportunity for SMARCA4 mutant lung cancer; we will identify drug combinations effective with ATR inhibition. We will build upon our discoveries by (Aim 1) comprehensively characterizing hallmarks of replication stress and assessing immune system activation in NSCLC clinical specimens with SMARCA4 mutations, (Aim 2) evaluating sensitivity of SMARCA4-mutant NSCLCs to therapies targeting replication stress defects, and (Aim 3) performing pre-clinical studies to assess the anti-tumor effects of ATR inhibition in combination with anti-PD1/PD-L1 immunotherapy. We will leverage existing preclinical models of SMARCA4- mutant, BRG1-deficient NSCLC generated in the Kim Lab (CRISPR-generated isogenic BRG1-deficient lines, GEMM) and Hata Lab (BRG1-deficient patient-derived xenograft (PDX)), together with patient samples from Drs. Dagogo-Jack and Cheng to evaluate the antitumor activity of rational combinations of candidate drugs to support future development of clinical trials. Overall, the studies proposed in this grant aim to advance the care of patients with SMARCA4-mutant NSCLC by exploring a novel, promising approach that exploits a unique vulnerability induced by BRG1 deficiency. We envision that the work proposed in this study will inform clinical trials exploring novel combination therapy approaches (ATR inhibition plus immunotherapy or gemcitabine) in patients with BRG1-deficient NSCLC, potentially paving the way for future approvals.