(PQ1) Epigenetic effects of the premalignant field

该补助金是对RFA CA-15-008问题1的回应：对于癌前病变的肿瘤， 在这一领域的细胞特性可以用来设计策略，以抑制未来肿瘤的发展？一 我们要解决的关键问题是，癌前区域是如何具体重塑癌症的表观遗传景观的。 新出现的癌症促进转移行为，这占大多数癌症相关死亡。 甚至在恶性转化之前，表观基因组使谱系特异性表达不稳定并降解 模式.由于染色质修饰对环境线索有反应，这些早期的表观遗传变化很可能是 对于理解致瘤微环境如何决定随后的癌细胞， 表型。然而，很少有研究涉及癌前环境 广泛地重塑了表观基因组增强子是控制细胞类型特异性基因表达的关键元件 模式，并以协调的方式激活以确定细胞谱系。我们发现了一种新的 SHC 1基因的增强子，其驱动谱系特异性同种型p66 Shc的表达， 控制失巢凋亡并作为强转移抑制剂发挥作用。在转移性肺癌细胞中，我们发现， Aiolos，一种通常参与淋巴细胞谱系决定的染色质调节剂，使p66 Shc沉默 增强剂。Aiolos还沉默了除SHC 1外的多个粘附相关基因的推定增强子， 也诱导淋巴细胞归巢受体。在人类肿瘤中，高水平的Aiolos与肿瘤细胞的增殖显著相关。 生存率更低。此外，我们通过免疫组化观察到在正常支气管上皮细胞中Aiolos的异常表达， Aiolos阳性肺肿瘤附近的上皮细胞，但远离这些肿瘤的上皮细胞中没有，表明 肺癌细胞遗传的表观遗传场缺陷。最后，我们在肺中复制Aiolos的诱导， 癌细胞通过暴露于已知的特定炎症因子， 肿瘤发生并驱动淋巴细胞分化。在这一提议中，我们假设， 炎性癌前病变改变了肺上皮的增强子景观， 淋巴细胞样的特性，促进致命的并发症，如转移。在第一个目标中，我们将定义 Aiolos基因的增强子成分响应于这些因子。在第二个目标中，我们将构建一个 与Aiolos诱导相关的激活或解除激活的增强子的表观基因组全图谱， 鉴定负责上皮细胞表型变化的模式。在第三个目标中，我们将比较这些 与组织学正常的肺肿瘤上皮相比， 来自肿瘤邻近和远处组织的肺上皮。在第四个目标中，我们将尝试重写Aiolos- 通过功能表观基因组学指导组蛋白修饰。该项目在两个领域都开辟了新的领域， 肿瘤转移的概念基础和设计新的治疗方法。

This grant is a response to RFA CA-15-008, question 1: For tumors that arise from a pre-malignant field, what properties of cells in this field can be used to design strategies to inhibit the development of future tumors? A key question we address is how the pre-malignant field specifically reshapes the epigenetic landscape of emerging cancers to promote metastatic behavior, which accounts for the majority of cancer-related deaths. Even prior to malignant transformation, the epigenome destabilizes and degrades lineage specific expression patterns. Since chromatin modifications respond to environmental cues, these early epigenetic shifts are likely to be critical in understanding how the tumorigenic microenvironment determines subsequent cancer cell phenotype. However, very few studies have addressed the process by which the pre-malignant environment broadly reshapes the epigenome. Enhancers are key elements that control cell-type specific gene expression patterns, and are activated in a coordinated fashion to determine cell lineage. We have identified novel enhancers of the SHC1 gene which drive expression of the lineage-specific isoform p66Shc, a protein that controls anoikis and functions as a strong metastasis suppressor. In metastatic lung cancer cells, we find that Aiolos, a chromatin regulator normally involved in lymphocyte lineage determination, silences p66Shc enhancers. Aiolos also silences putative enhancers of multiple adhesion-related genes besides SHC1, while also inducing lymphocyte homing receptors. In human tumors, high levels of Aiolos correlate with markedly worse survival rates. Further, we note aberrant expression of Aiolos by IHC in normal-appearing bronchial epithelium adjacent to Aiolos-positive lung tumors but not in epithelium remote from these tumors, suggesting an epigenetic field defect inherited by lung cancer cells. Finally, we replicate the induction of Aiolos in lung cancer cells through exposure to specific inflammatory factors know to both promote inflammation-associated tumorigenesis and drive lymphocyte differentiation. In this proposal, we hypothesize that such factors within an inflammatory pre-malignant field shift the enhancer landscape of lung epithelium and confer certain lymphocyte-like properties that promote lethal complications such as metastasis. In the first Aim we will define enhancer constituents of the gene for Aiolos responsive to such factors. In the second aim we will construct an epigenome-wide map of enhancers either activated or decommissioned in association with Aiolos induction, to identify patterns responsible for changes in epithelial cell phenotype. In the third aim we will compare these enhancer landscapes to those found in lung tumor epithelium in comparison with those in histologically normal lung epithelium from tumor-adjacent and remote tissues. In the fourth aim we will attempt to rewrite Aiolos- directed histone modifications through functional epigenomics. This project charts new territory in both the conceptual basis of tumor metastasis and in the design of novel therapeutic approaches against it.