TGFBR1 Signaling in Colorectal Cancer

结直肠癌中的 TGFBR1 信号转导

• 批准号: 8833509
• 负责人: Boris Pasche
• 金额: $ 9.71万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8833509
• 关键词: 9q22; Address; Adenocarcinoma; Alleles; Azoxymethane; Breeding; Cell Proliferation; Cells; Chemopreventive Agent; Colon Carcinoma; Colonic Neoplasms; Colorectal Cancer; Data; Development; Embryo; Epithelial Cell Proliferation; Epithelium; Exhibits; Fibroblasts; Future; Gastrointestinal tract structure; Gene Expression; Genes; Genetic; Goals; Growth; Health; Human; In Vitro; Individual; Inherited; Intestinal Mucosa; Intestinal Neoplasms; Intestines; Link; Loss of Heterozygosity; Lymphoid Cell; MADH2 gene; MADH3 gene; MADH4 gene; Malignant Neoplasms; Maps; Mediating; Modeling; Molecular; Mus; Mutation; Nude Mice; Oncogenic; Pathogenesis; Pathology; Patients; Phenotype; Phosphorylation; Phosphorylation Inhibition; Positioning Attribute; Predisposition; Property; Protocols documentation; Public Health; Receptor Gene; Reporting; Research Personnel; Role; Science; Seminal; Signal Transduction; Stem Cell Development; Stem cells; TGFBR1 gene; Testing; Therapeutic Agents; Time; Transgenic Organisms; Tumor Stem Cells; Tumor Suppressor Genes; Tumor Suppressor Proteins; Variant; cancer prevention; cancer risk; cancer stem cell; cancer therapy; in vivo; innovation; mouse model; novel; null mutation; peripheral blood; receptor; research study; tumor; tumorigenesis

DESCRIPTION (provided by applicant): We generated a novel model of mice heterozygous for a targeted null mutation of Tgfbr1. When crossed with mice carrying a mutation in the Apc tumor suppressor gene, these mice develop twice as many intestinal tumors as wild-type littermates. Invasive adenocarcinoma with features of human colon cancer is only identified among ApcMin/+; Tgfbr1+/- mice, not among ApcMin/+; Tgfbr1+/+ mice and tumors do not exhibit loss of heterozygosity at the Tgfbr1 locus. TGF-?-mediated growth inhibition, phosphorylation of Smad2 and Smad3, and overall TGF-? signaling are mildly decreased in haploinsufficient embryonic fibroblasts. Decreased Smad2 and Smad3 phosphorylation is observed in the colonic epithelium crypts of ApcMin/+; Tgfbr1+/- mice. Decreased Smad signaling is associated with increased cell proliferation in the crypts of the intestinal mucosa and intestinal tumors. Thus, constitutively reduced Tgfbr1-mediated signaling is a potent modifier of colorectal cancer development. To determine the relevance of these findings in humans, we analyzed germline peripheral blood for TGFBR1 expression. We found that 29 of 242 (12.0%) patients with colorectal cancer but only three of 195 (1.5%) controls had evidence of germline allele-specific expression of TGFBR1 (TGFBR1 ASE). These results indicate that TGFR1 ASE is one of the most commonly inherited cause of colorectal cancer, which increases cancer risk by approximately 870%. Differences in TGF-?-mediated phosphorylation of SMAD2 and SMAD3 between human lymphoid cells from individuals with wild-type TGFBR1 and individuals with TGFBR1 ASE were comparable to those found between Tgbr1+/+ and Tgfbr1+/- mouse embryonic fibroblasts. It is the purpose of the studies outlined in this application to unravel the molecular mechanisms of Tgfbr1 haploinsufficiency in colorectal cancer through execution of three Specific Aims: First: To characterize the phenotype of Tgfbr1+/+ and Tgfbr1+/- mice with respect to colon cancer: The phenotype of Tgfbr1+/+ and Tgfbr1+/- mice will be evaluated in three different backgrounds (129Sv/J, C57BL/6 and FVB/N). Colon tumors will be induced using the azoxymethane protocol and by crossing the transgenic strains with Apc1638N/+ and KRASV12G; Apc1638N/+ mice. Second: To determine the role of Tgfbr1 haploinsufficiency in development of cancer stem cells and intestinal stem cells as well as the contribution of stromal and lymphoepithelial Tgfbr1 signaling to tumor formation: We will determine the growth of Tgfbr1+/+ and Tgfbr1+/- tumors in nude mice to evaluate the contribution of Tgfbr1 haploinsufficiency on tumor stem cell development. Using the Lgr5 mouse model, we will also assess whether Tgfbr1 haploinsufficiency enhances the development of intestinal stem cells. The role of Tgfbr1 haploinsufficiency within stromal and lymphoepithelial cells will be evaluated as it relates to colon cancer development. Third: To assess Tgfbr1 haploinsufficiency oncogenic properties: Using MEFs from three distinct genetic backgrounds (129Sv/J, C57BL/6 and FVB/N) we will determine the extent to which Tgfbr1 haploinsufficiency enhances oncogenesis.

描述（由申请人提供）：我们为TGFBR1的靶向零突变生成了一种新型小鼠的新型模型。当与APC肿瘤抑制基因中携带突变的小鼠越过时，这些小鼠的肠道肿瘤是野生型同窝仔的两倍。仅在APCMIN/+之间鉴定出具有人类结肠癌特征的侵入性腺癌； TGFBR1 +/-小鼠，不在apcmin/+中； TGFBR1+/+小鼠和肿瘤在TGFBR1基因座上没有表现出杂合性的丧失。 TGF - ？ - 介导的生长抑制作用，SMAD2和SMAD3的磷酸化以及总体TGF-？信号在单倍体的胚胎成纤维细胞中有轻度降低。在APCMIN/+的结肠上皮隐窝中观察到SMAD2和SMAD3磷酸化的降低； TGFBR1 +/-小鼠。 SMAD信号的降低与肠粘膜和肠道肿瘤隐窝中细胞增殖的增加有关。因此，组成性降低的TGFBR1介导的信号传导是结直肠癌发展的有效修饰符。为了确定这些发现在人类中的相关性，我们分析了种系外周血的TGFBR1表达。我们发现，结直肠癌的242例（12.0％）患者中有29例（12.0％），但195例（1.5％）的对照中只有3例具有TGFBR1（TGFBR1 ASE）的种系等位基因特异性表达的证据。这些结果表明，TGFR1 ASE是结直肠癌最常见的原因之一，可将癌症风险增加约870％。 TGF - ？？ - 媒体型TGFBR1个体和TGFBR1 ASE个体的人淋巴样细胞之间SMAD2和SMAD3介导的磷酸化的差异与TGBR1+/+和TGFBR1和TGFBR1 +/-小鼠胚胎成纤维细胞之间发现的差异与TGFBR1 ASE的个体相当。这是该应用中概述的研究的目的是通过执行三个特定目的来阐明结直肠癌中TGFBR1单倍症的分子机制：首先：表征TGFBR1+/+和TGFBR1 +/-小鼠的表征与TGFBR1+/TGFBR1 +/ TGFBR1 +/ TGFBR1 +/ TGFBR1 +/ （129SV/J，C57BL/6和FVB/N）。结肠肿瘤将使用甲氧基甲烷方案诱导，并通过将转基因菌株与APC1638N/+和KRASV12G诱导； APC1638N/+小鼠。第二：确定TGFBR1单倍不使癌症干细胞和肠道干细胞发育的作用以及基质和淋巴皮上皮TGFBR1信号对肿瘤形成的贡献：我们将确定TGFBR1+/+和TGFBR1 +/- tgfbr1 +/- thuude小鼠对THUSF的贡献TGFBR1的生长。使用LGR5小鼠模型，我们还将评估TGFBR1单倍不足是否可以增强肠道干细胞的发展。 TGFBR1单倍体弥补在基质和淋巴皮细胞中的作用将与结肠癌发育有关。第三：为了评估TGFBR1单倍性致癌特性：使用来自三种不同遗传背景的MEF（129SV/J，C57BL/6和FVB/N），我们将确定TGFBR1单倍耐弥补的增强的程度。