CDHR5 tumor suppressor function in the intestine

CDHR5在肠道中的抑癌功能

• 批准号: 10299388
• 负责人: William Scott Crawley
• 金额: $ 44.92万
• 依托单位: UNIVERSITY OF TOLEDO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10299388
• 关键词: Adhesions; Adhesives; Affinity; Apical; Binding; Brush Border; CRISPR/Cas technology; Cadherin Domain; Cadherins; Cancer Patient; Cell Adhesion Molecules; Cell model; Cells; Chemopreventive Agent; Colitis associated colorectal cancer; Collection; Colon; Colon Carcinoma; Colorectal Cancer; Complex; Cytoplasmic Tail; Defect; Development; Disease; Distal; Enterocytes; Epithelial Cells; Exhibits; Family member; Goals; Implant; Inflammation; Intestines; Knock-out; Knowledge; Length; Link; Malignant - descriptor; Mass Spectrum Analysis; Mesalamine; Mission; Modeling; Molecular; Mucins; Mucous Membrane; Mus; Non-Steroidal Anti-Inflammatory Agents; Nude Mice; Outcome; Pharmaceutical Preparations; Property; Protein Isoforms; Proteins; Public Health; Published Comment; RNA Splicing; Research; Role; Source; Surface; Testing; Therapeutic; Toxic effect; Tumor Suppression; Tumor Suppressor Proteins; United States National Institutes of Health; Up-Regulation; Xenograft procedure; base; beta catenin; cancer cell; cancer survival; cellular microvillus; colitis associated cancer; colon cancer cell line; colorectal cancer prevention; colorectal cancer treatment; density; extracellular; gastrointestinal; gastrointestinal epithelium; glycosylation; implantation; in vivo; innovation; intestinal epithelium; intestinal homeostasis; knock-down; member; mouse model; neoplastic; overexpression; polarized cell; prevent; programs; protein protein interaction; protein purification; small hairpin RNA; solute; tumor

Cadherin related family member 5 (CDHR5) is a type 1 transmembrane adhesion molecule that is highly expressed in the gut epithelium, but is almost always lost in colorectal cancer (CRC). The promising CRC chemopreventive drug 5-ASA (mesalazine) potently upregulates CDHR5 expression as part of its chemopreventive activity, and direct overexpression of CDHR5 reduces the tumor formation potential of CRC cells that have been injected into mice. Together, these results implicate CDHR5 as a tumor suppressor in the gut. Despite this, the functional properties of CDHR5 that allow it to act as a tumor suppressor have not been defined. This represents a significant gap in knowledge of how CDHR5 acts as a barrier against CRC. This knowledge gap prevents the development of chemopreventive CRC therapies involving upregulation of CDHR5, as seen with the drug 5-ASA. The long-term goal of this study is to understand the role of the adhesion molecule CDHR5 in the intestine. The current objective of this proposal is to directly investigate the properties of CDHR5 that allow it to suppress CRC in the gut. Preliminary studies discovered that CDHR5 localizes to the distal tips of microvilli that cover the apical surface of intestinal epithelial cells. Here, CDHR5 forms a strong extracellular interaction with another cadherin, CDHR2, to physically link neighboring microvilli together, organizing them into an ordered array known as the intestinal brush border. Overexpression of CDHR5 results in a striking effect on CRC cells, with cells polarizing to form an increased density of apical microvilli that are longer in length. This shift towards a ‘hyper-polarized’ state is partially dependent upon the intracellular cytoplasmic domain of CDHR5. For this proposal, the central hypothesis is that CDHR5 contributes to the integrity of the intestinal epithelium to guard against CRC development, in a manner dependent on CDHR5 cytoplasmic binding partners and its extracellular adhesion activity. This hypothesis will be tested through three specific aims: 1) Determine the functional interplay between the two splice isoforms of CDHR5. This aim will explore the discovery that the two splice isoforms of CDHR5 interact to form a mature functional complex that targets to apical microvilli. 2) Identify factors associated with the cytoplasmic domain of CDHR5. This aim will employ an innovative protein purification approach to directly identify the in vivo binding partners for the cytoplasmic domain of CDHR5. The role of binding partners in CDHR5 function will be explored using knockdown/knockout studies an enterocyte model. 3) Determine the functional properties of CDHR5 required to reduce the tumor formation potential of CRC cells that have been implanted in a nude mouse model. This aim will assess whether the adhesion capacity and/or cytoplasmic binding partners are required for CDHR5 to reduce tumor formation of CRC cells. The approach is innovative, since it challenges the existing viewpoint that CDHR5 functions as a tumor suppressor in the gut by interacting with and sequestering β-catenin. The proposed research is significant because loss of CDHR5 is highly correlated with development of CRC and predicts poor survival of cancer patients.

钙粘蛋白相关家族成员5（CDHR 5）是一种1型跨膜粘附分子，其高度依赖于细胞膜。 在肠上皮中表达，但在结直肠癌（CRC）中几乎总是丢失。有前途的CRC 化学预防药物5-阿萨（美沙拉秦）有效上调CDHR 5表达，作为其 化学预防活性和CDHR 5的直接过表达降低了CRC的肿瘤形成潜力 注射到老鼠体内的细胞。总之，这些结果暗示CDHR 5作为一种肿瘤抑制因子， 直觉尽管如此，CDHR 5作为肿瘤抑制因子的功能特性还没有被证实。 定义了这表明，在人权委员会第五次会议如何成为反对《儿童权利公约》的障碍方面存在着重大的知识差距。这 知识差距阻碍了涉及上调CDHR 5的化学预防性CRC疗法的发展， 如药物5-阿萨所见。这项研究的长期目标是了解粘附分子的作用 肠道中的CDHR 5。本提案的当前目标是直接研究CDHR 5的性质 从而抑制肠道中的CRC。初步研究发现，CDHR 5定位于远端尖端， 微绒毛覆盖在肠上皮细胞的顶端表面。在这里，CDHR 5形成了一个强大的细胞外 与另一种钙粘蛋白CDHR 2相互作用，将相邻的微绒毛物理连接在一起，将它们组织成 一种被称为肠道刷状缘的有序阵列。CDHR 5的过表达导致对细胞凋亡的显著影响。 CRC细胞，细胞极化形成密度增加的顶端微绒毛，长度更长。这 向“超极化”状态的转变部分取决于CDHR 5的细胞内胞质结构域。 对于这个提议，中心假设是CDHR 5有助于肠上皮的完整性， 以依赖于CDHR 5细胞质结合伴侣及其 细胞外粘附活性。这一假设将通过三个具体目标进行检验：1）确定 CDHR 5的两种剪接异构体之间的功能相互作用。这一目标将探索发现， CDHR 5的剪接异构体相互作用以形成靶向顶端微绒毛的成熟功能复合物。2)识别 与CDHR 5胞质结构域相关的因子。这一目标将采用创新的蛋白质纯化 直接鉴定CDHR 5胞质结构域的体内结合配偶体的方法。的作用 CDHR 5功能中的结合配偶体将使用肠上皮细胞模型的敲除/敲除研究来探索。 3)确定降低CRC细胞的肿瘤形成潜力所需的CDHR 5的功能特性 移植到裸鼠模型中。这一目的将评估粘附能力和/或 细胞质结合配偶体是CDHR 5减少CRC细胞的肿瘤形成所必需的。该方法是 创新，因为它挑战了现有的观点，即CDHR 5在肠道中作为肿瘤抑制因子发挥作用， 与β-连环蛋白相互作用并隔离β-连环蛋白。这项研究是重要的，因为CDHR 5的丢失是 与CRC的发展高度相关，并预测癌症患者的生存率低。