Roles and regulation of transcriptional reprogramming in squamous carcinogenesis

转录重编程在鳞状细胞癌发生中的作用和调控

基本信息

批准号：
10673755
负责人：
Markus Schober
金额：
$ 47.59万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2027-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10673755
关键词：
ATAC-seq Binding Biological Assay Carcinoma Cell Nucleus Cells ChIP-seq Chemicals Chromatin Chromatin Conformation Capture and Sequencing Clonal Expansion Cutaneous Data Development Disease Enhancers Epigenetic Process Epithelial Cells Esophagus Event Gene Expression Gene Expression Profile Genetic Genetic Transcription Genomics Growth Heterogeneity Human Inflammation Link Lung Malignant Epithelial Cell Malignant Neoplasms Measures Modeling Molecular Molecular Conformation Mus Mutation Mutation Detection Oncogenic Pancreas Patients Phosphorylation Physiological Positioning Attribute Premalignant Cell Process Proto-Oncogenes RUNX1 gene Regulator Genes Regulatory Element Reporter Repression Research Resected Role Signal Pathway Signal Transduction Site Skin Skin Carcinogenesis Squamous Differentiation Squamous cell carcinoma Testing Therapeutic Tissues Transcription Initiation Transcriptional Regulation Transducers Transposase Tumor Promotion Tumor Suppressor Genes United States Visualization cancer cell carcinogenesis cell transformation checkpoint inhibition chromatin immunoprecipitation chromosome conformation capture epidermal stem cell epithelial stem cell gain of function genetic signature genome-wide analysis human model improved insight loss of function mouse model novel strategies organ transplant recipient premalignant prevent programs promoter response self-renewal stem cells stem-like cell transcription factor transcriptional reprogramming transcriptome transcriptome sequencing tumor tumor growth tumor initiation wound

项目摘要

SUMMARY Mutations that activate proto-oncogenes or inactivate tumor suppressor genes are the root causes of tumor initiation, but recent genomic analyses also detect these mutations in many cells of healthy tissues. These data and classic skin carcinogenesis studies suggest that mutations in proto-oncogenes or tumor-suppressor genes are tolerated and maintained in epidermal progenitor cells (EPCs) until elusive mechanisms transform these precancerous cells into stem-cell-like tumor propagating cells (TPCs) that can support tumor formation and growth. We transcriptionally profiled these TPCs in squamous cell carcinoma (SCC) models and defined a gene expression signature that distinguishes TPCs from EPCs. Within this signature, we identified the transcription factors PITX1 and SOX2 in >60% of mouse and human SCCs, even though they are epigenetically repressed and not detectable in normal skin epithelial cells. We showed PITX1 and SOX2 are required for SCC growth in mouse and patient-derived SCC models highly enriched on gene regulatory enhancers accessible in TPCs but not EPCs, and responsible for the expression of SCC signature genes. Although PITX1 and SOX2 are pivotal for squamous carcinogenesis, it is still unclear what events trigger their de novo expression in TPCs, and whether their ability to bind condensed (inactive) chromatin and open it to activate SCC-specific gene expression reprograms EPCs into TPCs. Here, we propose to test the hypothesis that oncogenic RAS and inflammation together or independently activate RUNX1, which initiates expression of PITX1 and then SOX2, allowing them to transcriptionally reprogram EPCs into TPCs that promote squamous carcinogenesis. To test this hypothesis, we propose to: 1) determine whether and how inflammation-induced RUNX1 activity promotes de novo PITX1 expression in normal and pre-cancerous skin epithelial cells; and 2) determine whether and how ectopically expressed RUNX1, PITX1, and/or SOX2 reprogram EPCs into TPCs to promote SCC initiation. To accomplish these aims, we already established genetic gain- and loss-of-function approaches in autochthonous mouse and human SCC models along with genome-wide analyses (ATAC-seq, ChIP-seq, 4C-seq, RNA-seq) and fluorescent transcriptional reporter assays. We are uniquely positioned to reveal the molecular events that explain: 1) how PITX1 and SOX2 become expressed de novo in mouse and human SCCs, 2) whether SOX2 and PITX1 establish or use SCC-defining gene regulatory enhancers to control the expression of SCC signature genes, and 3) how these changes in gene expression transform precancerous cells into TPCs that promote squamous carcinogenesis. Our proposed research will provide molecular insights that promise to guide the development of approaches to prevent or treat SCCs in patients and/or define mechanisms that may promote the initiation of other cancers including but not limited to lung, esophageal, and pancreatic SCCs, which are among the most common deadly cancers.

概括激活原癌基因或失活抑癌基因的突变是肿瘤发生的根本原因但最近的基因组分析也在健康组织的许多细胞中检测到这些突变。这些数据经典的皮肤癌发生研究表明，原癌基因或抑癌基因的突变在表皮祖细胞（EPC）中被耐受和维持，直到难以捉摸的机制改变这些癌前细胞转化为干细胞样肿瘤增殖细胞（TPC），可以支持肿瘤形成和生长。我们在鳞状细胞癌 (SCC) 模型中对这些 TPC 进行了转录分析，并定义了一个基因区分 TPC 和 EPC 的表达式签名。在这个签名中，我们识别了转录在超过 60% 的小鼠和人类 SCC 中影响 PITX1 和 SOX2，即使它们受到表观遗传抑制在正常皮肤上皮细胞中检测不到。我们证明 PITX1 和 SOX2 是 SCC 生长所必需的小鼠和患者来源的 SCC 模型高度富集 TPC 中可利用的基因调控增强子，但不是 EPC，并且负责 SCC 特征基因的表达。尽管 PITX1 和 SOX2 至关重要对于鳞状细胞癌发生，目前尚不清楚什么事件触发它们在 TPC 中从头表达，以及是否它们能够结合浓缩（非活性）染色质并将其打开以激活 SCC 特异性基因表达将 EPC 重新编程为 TPC。在这里，我们建议检验致癌 RAS 和炎症共同或独立激活 RUNX1，从而启动 PITX1 的表达，然后 SOX2，允许他们将 EPC 转录重编程为促进鳞状细胞癌的 TPC 致癌作用。为了检验这一假设，我们建议：1）确定炎症是否以及如何诱发 RUNX1 活性促进正常和癌前皮肤上皮细胞中从头表达 PITX1；和 2) 确定异位表达的 RUNX1、PITX1 和/或 SOX2 是否以及如何将 EPC 重编程为 TPC，以促进SCC的发生。为了实现这些目标，我们已经确定了遗传功能的获得和丧失本地小鼠和人类 SCC 模型中的方法以及全基因组分析（ATAC-seq， ChIP-seq、4C-seq、RNA-seq）和荧光转录报告基因检测。我们拥有独特的定位揭示解释以下问题的分子事件：1) PITX1 和 SOX2 如何在小鼠中从头表达人类 SCC，2) SOX2 和 PITX1 是否建立或使用 SCC 定义基因调控增强子来控制 SCC 特征基因的表达，以及 3) 这些基因表达的变化如何转化为癌前病变细胞转化为 TPC，促进鳞状细胞癌变。我们提出的研究将提供分子见解有望指导预防或治疗患者鳞状细胞癌的方法的开发和/或定义可能促进其他癌症发生的机制，包括但不限于肺癌、食道癌和胰腺鳞状细胞癌，这是最常见的致命癌症之一。