A NOVEL LINEAGE SPECIFIC METASTASIS PATHWAY IN LUNG CANCER

肺腺癌（LUAD）是组织学上最多样化的肺癌亚型， 转移到中枢神经系统（CNS）。我们的目标是确定LUAD的分子决定因素 谱系和组织学异质性及其对转移的生物学后果。我们之前发现 一种新的谱系选择性转录程序，限制LUAD细胞的侵袭，并表明这一点， 在高级别LUAD中，通路受到抑制。在这里，我们提供的证据表明，侵入性LUAD细胞可以激活 一种神经内分泌样基因特征，一旦肿瘤细胞扩散到大脑中，这种基因特征就会被进一步诱导。这 这种现象与能够转移的KRAS突变细胞中普遍的染色质改变有关。 此外，人类肿瘤中神经内分泌样基因的激活与不同的形态学特征相关。 CNS复发风险的LUAD亚组。我们假设：1）LUAD谱系重编程由以下因素驱动： 染色质修饰蛋白，2）组织学异质性是高级别适应能力的衡量标准。 LUAD，和3）神经内分泌谱系的激活特别与其易感性相关， CNS复发。许多神经内分泌基因编码具有双重腺和神经活性的分泌蛋白 功能协调发展的因此，我们还提出，4）神经内分泌样基因的子集使播散性LUAD 细胞以建立脑转移生长所需的神经原性小生境。 我们的机制预测将通过整合表观基因组学，功能基因组学， 实验生物学这些方法适用于现有的LUAD模型，以及新的模型，这是 在小鼠中进行工程改造，或从通过我们独特的耶鲁肺癌患者同意的患者活检中获得 活检方案。在目的1中，我们进行了功能基因组筛选，以提名组蛋白甲基转移酶 ASH 1 L作为谱系可塑性和转移能力的新型表观遗传驱动因子我们将确定阶段 在LUAD进展和转移过程中对ASH 1 L的特定要求，并确定其机制， 它调节转移细胞的转录组。在目标2中，我们确定了神经内分泌/神经活性的双重 因子FGF 9在LUAD细胞中被表观遗传激活并且是脑转移所需的。我们将从基因上 测试肿瘤细胞衍生的FGF 9刺激少突胶质细胞祖细胞支持转移的预测， 通过旁分泌Sonic Hedgehog信号传导。最后，根据目标1和2，我们将利用人类 生物标本研究表观基因组改变，神经内分泌标志物表达， 组织学异质性和LUAD的临床结局。 胸部恶性肿瘤占大多数癌症相关死亡。我们互补的目标提供了一个令人信服的 机制框架，以了解肺规范，神经功能， 和CNS复发。最后，我们的建议将产生重要的洞察力，以如何前瞻性表观遗传 这些疗法可用于辅助疗法和/或晚期脑转移的治疗。

Lung adenocarcinoma (LUAD) is the most histologically diverse lung cancer subtype and frequently metastasizes to the central nervous system (CNS). Our goal is to identify the molecular determinants of LUAD lineage and histological heterogeneity and their biological consequences for metastasis. We previously identified a novel lineage selective transcriptional program that constrains LUAD cell invasion, and showed that this pathway is suppressed in high grade LUADs. Here, we provide evidence that invasive LUAD cells can activate a neuroendocrine-like gene signature, which is further induced once tumor cells disseminate into the brain. This phenomenon is linked to pervasive chromatin alterations in KRAS mutant cells that are competent for metastasis. Moreover, activation of neuroendocrine-like genes in human tumors correlates with distinct morphological subgroups of LUAD at risk for CNS relapse. We hypothesize that: 1) LUAD lineage reprogramming is driven by chromatin modifying proteins, 2) histological heterogeneity is a measure of the adaptive capacity of high grade LUADs, and 3) the activation of the neuroendocrine lineage in particular correlates with their predisposition for CNS relapse. Many neuroendocrine genes encode for secreted proteins with dual glandular and neuroactive functions. Hence, we also propose that 4) a subset of neuroendocrine-like genes enables disseminated LUAD cells to establish a neurogenic niche that is required for brain metastatic outgrowth. Our mechanistic predictions will be studied by integrating epigenomics, functional genomics, and experimental biology. These methods are applied to existing models of LUAD, as well as new models, which are engineered in mice or derived from biopsies of patients consented through our unique Yale Lung Cancer Patient Biopsy protocol. In Aim 1, we performed a functional genomic screen to nominate the histone methyltransferase ASH1L as a novel epigenetic driver of lineage plasticity and metastatic competence. We will ascertain the stage specific requirement for ASH1L during LUAD progression and metastasis, and identify the mechanism by which it regulates the transcriptome of metastatic cells. In Aim 2, we identified the dual neuroendocrine/neuroactive factor FGF9 as being epigenetically activated in LUAD cells and required for brain metastasis. We will genetically test the prediction that tumor cell derived FGF9 stimulates oligodendrocyte progenitor cells to support metastatic outgrowth via paracrine Sonic Hedgehog signaling. Finally, under both Aims 1 and 2, we will utilize human biospecimens to study the relationship between epigenomic alterations, neuroendocrine marker expression, histological heterogeneity, and clinical outcome in LUAD. Thoracic malignancies account for most cancer-related deaths. Our complementary Aims provide a cogent mechanistic framework to understand the biological link between pulmonary specification, neurogenic functions, and CNS relapse. Finally, our proposal will generate significant insight as to how prospective epigenetic therapies can be harnessed for adjuvant therapy and/or the treatment of late stage brain metastasis.