Maturation of Colon Cancer Cells

结肠癌细胞的成熟

• 批准号: 6944708
• 负责人: John M Mariadason
• 金额: $ 24.37万
• 依托单位: MONTEFIORE MEDICAL CENTER (BRONX, NY)
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-30 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6944708
• 关键词: amidohydrolases; butyrates; carcinogenesis; cell differentiation; cell growth regulation; cell line; colon neoplasms; enzyme inhibitors; functional /structural genomics; gastrointestinal epithelium; gene induction /repression; isozymes; laboratory mouse; microarray technology; oncoprotein p21

DESCRIPTION (provided by applicant): Butyrate is a short-chain fatty acid with significant physiological relevance for the proper functioning of the colonic epithelium. In colon cancer cell lines in vitro, butyrate consistently induces a defined maturation response, involving p21WAF1-dependent cell cycle arrest, lineage specific differentiation and apoptosis. Butyrate is a potent and direct inhibitor of histone deacetylase (HDAC) activity. Importantly, butyrate-induction of colon cell maturation is mimicked by the specific, yet structurally unrelated HDAC-inhibitor, trichostatin A, suggesting inhibition of HDAC activity is a critical component of the butyrate response. We recently used cDNA microarrays to demonstrate that butyrate-induction of colon cell maturation is driven by extensive genetic reprogramming, involving the recruitment of approximately 7 % of over 8000 sequences analyzed. Furthermore, we identified a subset of these genes which are coordinately regulated by trichostatin A, indicating a key role for HDACs in their regulation. Currently, 18 distinct HDACs have been identified in eukaryotic cells. These can be categorized into one of three distinct classes based upon their homology to their prototypical yeast HDAC. Genomewide microarray analysis in yeast has clearly demonstrated that different HDACs regulate distinct cellular processes (1, 2). Whether this is also the case in mammalian cells, and whether inhibition of specific HDACs drives different components of the butyrate response is not known. Furthermore, the link between inhibition of HDAC activity and the induction of colon cell maturation suggests a key role for HDACs in the physiological regulation of colon cell maturation in vivo. In this study, we will dissect the contribution of HDACs 1, 2 and 4, to the various components of the butyrate response. In aim 1, we will utilize our experience with cDNA microarrays to address this question on a genomewide scale. In aim 2, we will use the well-defined, and critical component of the butyrate response, induction of p21WAF1promoter activity, to determine the role of these same HDACs on butyrate-induction of a specific target gene. Aim 3 will extend these observations to determine the role of HDACs in other models of colon cell maturation, and most important, in the maturation of normal colonic and small intestinal epithelial cells, in vivo. Finally, while HDAC-inhibitors induce classical anti-tumor effects in vitro their effect on intestinal tumor formation has not been tested in vivo. Therefore, in aim 4, we will capitalize on our experience with mouse models to determine the effect of two inhibitors of HDAC activity, butyrate and trichostatin A on ApcMin-initiated intestinal tumorigenesis in vivo. Collectively, these studies are designed to define the role of specific HDACs in the regulation of colon cell maturation. Understanding the critical pathways that drive normal colonic epithelial cell maturation will enhance our understanding of how colorectal tumorigenesis is initiated, which in turn, will improve our ability to prevent and treat this disease.

描述（由申请人提供）：丁酸盐是一种短链脂肪酸，对于结肠上皮的正常功能具有显着的生理相关性。在体外结肠癌细胞系中，丁酸盐始终诱导明确的成熟反应，包括 p21WAF1 依赖性细胞周期停滞、谱系特异性分化和凋亡。丁酸盐是组蛋白脱乙酰酶 (HDAC) 活性的有效直接抑制剂。重要的是，丁酸盐诱导结肠细胞成熟是由特定但结构上不相关的 HDAC 抑制剂曲古抑菌素 A 模拟的，这表明 HDAC 活性的抑制是丁酸盐反应的关键组成部分。我们最近使用 cDNA 微阵列证明丁酸诱导结肠细胞成熟是由广泛的基因重编程驱动的，涉及招募分析的 8000 多个序列中的约 7%。此外，我们还确定了这些基因的一个子集，它们受到曲古抑菌素 A 的协调调节，表明 HDAC 在其调节中发挥着关键作用。目前，已在真核细胞中鉴定出 18 种不同的 HDAC。根据它们与其原型酵母 HDAC 的同源性，可以将它们分为三个不同类别之一。酵母全基因组微阵列分析清楚地表明，不同的 HDAC 调节不同的细胞过程 (1, 2)。哺乳动物细胞中是否也是如此，以及特定 HDAC 的抑制是否会驱动丁酸盐反应的不同组成部分尚不清楚。此外，抑制 HDAC 活性与诱导结肠细胞成熟之间的联系表明 HDAC 在体内结肠细胞成熟的生理调节中发挥着关键作用。在本研究中，我们将剖析 HDAC 1、2 和 4 对丁酸盐反应各个组成部分的贡献。在目标 1 中，我们将利用 cDNA 微阵列的经验在全基因组范围内解决这个问题。在目标 2 中，我们将使用丁酸反应的明确且关键的组成部分，即 p21WAF1 启动子活性的诱导，来确定这些相同的 HDAC 在特定靶基因的丁酸诱导中的作用。目标 3 将扩展这些观察结果，以确定 HDAC 在结肠细胞成熟的其他模型中的作用，最重要的是，在体内正常结肠和小肠上皮细胞成熟中的作用。最后，虽然 HDAC 抑制剂在体外诱导经典的抗肿瘤作用，但它们对肠道肿瘤形成的影响尚未在体内进行测试。因此，在目标 4 中，我们将利用小鼠模型的经验来确定两种 HDAC 活性抑制剂丁酸盐和曲古抑菌素 A 对 ApcMin 引发的体内肠道肿瘤发生的影响。总的来说，这些研究旨在明确特定 HDAC 在结肠细胞成熟调节中的作用。了解驱动正常结肠上皮细胞成熟的关键途径将增强我们对结直肠肿瘤发生如何启动的理解，进而提高我们预防和治疗这种疾病的能力。