Epigenetic regulation of NKX2-1-negative lung adenocarcinoma cellular identity by FoxA1 and FoxA2

项目摘要 肺癌是导致男性和女性癌症死亡的主要原因。尽管筛查技术取得了进步 方法和个体化治疗，患者预后仍然令人沮丧，5年生存率从4-4岁不等。 17%。肺腺癌(LUAD)是这种疾病最常见的亚型，表现出大量的 细胞特性或组织分化状态的异质性。细胞身份的变化已经显示出来 与患者预后、对化疗的敏感性等临床参数密切相关 耐药性的发展。目前，该领域缺乏对分子的全面了解。 调节肺腺癌细胞特性和控制肿瘤进展的网络。识别 转录调控大师将为癌症进展和LE的机制提供新的见解 为制定针对肿瘤分化状态的治疗策略奠定基础。 侵袭性粘液腺癌(IMA)是LUAD的一种亚型，它经历了从肺到胃的谱系 在其自然发展过程中切换。使用基因工程小鼠模型，我们发现这种丢失 肺系基因NKX2-1/TTF1的缺失导致LUAD的胃转分化，产生小鼠 概述了人类IMA的形态和基因表达谱的肿瘤。这种胃谱系开关 部分是通过先锋因子FoxA1和FOXA2(FoxA1/2)的染色质差异结合而介导的 在整个基因组中重新定位，从肺基因到胃基因的调控元件。在NKX2-1失败后， 这些胃基因也经历与基因激活相关的染色质修饰，包括增加 组蛋白3赖氨酸27乙酰化(H3K27ac)。然而，目前尚不清楚是否需要FoxA1/2 介导这些染色质在其从头结合位置的改变，从而促进肿瘤谱系 正在切换。FoxA1/2除了调节肺到胃的转分化外，还调节LUAD 对靶向治疗作出反应的身份。丝裂原活化蛋白激酶的药理抑制 在NKX2-1阴性的LUAD中，信号级联不仅导致肿瘤消退，还导致胃 依赖于FoxA1/2活性的谱系开关。因此，这项提案的目标是确定 FoxA1/2调控NKX2-1阴性LUAD染色质景观的机制 癌症身份。中心假说是FoxA1/2重组染色质可及性并修饰组蛋白/ DNA甲基化景观，以控制LUAD身份。为了检验这一假设，我们将确定 在已建立的肿瘤中，Nkx2-1缺失后染色质调节需要FOXA1/2，并定义 FoxA1/2介导这些变化的精确机制。这项建议意义重大，因为它将提供 对调控LUAD细胞身份和肿瘤进展的分子网络有了更深入的了解， 这些发现对于制定针对特定亚型的干预措施至关重要。

PROJECT ABSTRACT Lung cancer is the leading cause of cancer mortality in both men and women. Despite advances in screening methods and personalized therapy, patient prognosis remains dismal with 5-year survival rates varying from 4- 17%. Lung adenocarcinoma (LUAD), the most frequently diagnosed subtype of this disease, exhibits substantial heterogeneity in its cellular identity or tissue differentiation state. Changes in cellular identity have been shown to strongly correlate with clinical parameters including patient prognosis, sensitivity to chemotherapy, and development of drug resistance. Currently, the field lacks a comprehensive understanding of the molecular networks that regulate lung adenocarcinoma cell identity and govern tumor progression. Identifying master transcriptional regulators will provide novel insight into the mechanisms of cancer progression and lay the groundwork for the development of therapeutic strategies specific to tumor differentiation state. Invasive mucinous adenocarcinoma (IMA) is a subtype of LUAD that undergoes pulmonary to gastric lineage switching during its natural progression. Using genetically engineered mouse models, we have found that loss of the pulmonary lineage specifier NKX2-1/TTF1 causes gastric transdifferentiation in LUAD, generating murine tumors that recapitulate the morphology and gene expression profile of human IMA. This gastric lineage switch is mediated in part by differential chromatin binding of pioneer factors, FoxA1 and FoxA2 (FoxA1/2), which relocate throughout the genome from pulmonary loci to regulatory elements of gastric genes. Upon NKX2-1 loss, these gastric genes also undergo chromatin modifications associated with gene activation including increases in histone 3 lysine 27 acetylation (H3K27ac). However, it is unknown whether FoxA1/2 are required to mediate these chromatin alterations at their de novo binding sites and thereby, facilitate tumor lineage switching. In addition to regulating the pulmonary-to-gastric transdifferentiation, FoxA1/2 also modulate LUAD identity in response to targeted therapy. Pharmacologic inhibition of the mitogen-activated protein kinase signaling cascade not only causes tumor regression in NKX2-1-negative LUAD, but also results in a gastric lineage switch that is dependent upon FoxA1/2 activity. Thus, the objective of this proposal is to determine the mechanism by which FoxA1/2 modulate the chromatin landscape of NKX2-1-negative LUAD in order to control cancer identity. The central hypothesis is that FoxA1/2 restructure chromatin accessibility and modify the histone/ DNA methylation landscape in order to control LUAD identity. To test this hypothesis, we will determine whether FoxA1/2 are required for chromatin modulation following Nkx2-1 deletion in established tumors and define the precise mechanism by which FoxA1/2 mediate these changes. This proposal is significant because it will provide a deeper understanding of the molecular networks that regulate LUAD cellular identity and tumor progression, findings which are essential for the development of subtype-specific interventions.