ROLE OF BGP IN BREAST EPITHELIAL CELL POLARIZATION

BGP 在乳腺上皮细胞极化中的作用

• 批准号: 6633567
• 负责人: John Ernest Shively
• 金额: $ 41.15万
• 依托单位: BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6633567
• 关键词: MCF7 cell; breast neoplasms; carcinogenesis; cellular polarity; glycoproteins; mammary epithelium

The hallmark of epithelial cells is their polarized morphology and lumen formation. BGP (biliary glycoprotein), a type I transmembrane glycoprotein that is found throughout the gastrointestinal tract and other organs such as the breast, has a polarized expression on the lumenal surface of epithelial cells. We have shown that BGP plays an essential role in the lumen formation of the 'normal" breast epithelial cell line MCF10F when grown in matrigel, a source of extracellular matrix. Specifically, these cells fail to form a lumen (acinus) when BGP expression is blocked with a BGP anti-sense gene, or when the cells are treated with anti-BGP antibody or with recombinant, soluble BGP. In the case of breast tumor cell lines such as MCF7, which fail to form acini in matrigel and do not express BGP, these cells exhibit massive cell death and occasional acinus formation when transfected with the BGP sense gene and grown in matrigel. In order to delineate the molecular determinants of lumen formation by BGP, we propose to (1) study the defects in MCF7 cells which prevent their reversion to a more "normal" phenotype, (2) map cytoskeleton interactions with the cytoplasmic domain of BGP, (3) analyze the cis-trans dimer interactions of the BGP ectodomains responsible for lumen formation, and (4) determine the regulation of the BGP gene in both MCF10F and MCF7 cells. In addition, we have found that MCF10F cells produce myoepithelial cells which can be enriched and shown to be BGP negative and capable of induction of CEA (carcinoembryonic antigen), a hallmark of breast cancer cells. We will also study the regulation of the CEA and BGP genes in these cells in order to gain insight into the process of tumorigenesis in breast cancer.

上皮细胞的标志是其极化形态和管腔形成。 BGP（胆汁糖蛋白）是一种 I 型跨膜糖蛋白，存在于整个胃肠道和其他器官（例如乳房）中，在上皮细胞的管腔表面上具有极化表达。我们已经证明，当在基质胶（细胞外基质的来源）中生长时，BGP 在“正常”乳腺上皮细胞系 MCF10F 的管腔形成中发挥着重要作用。具体而言，当 BGP 表达水平降低时，这些细胞无法形成管腔（腺泡）。对于乳腺肿瘤细胞系（例如 MCF7），用 BGP 反义基因阻断，或者用抗 BGP 抗体或重组可溶性 BGP 处理细胞时，会发生这种情况。在基质胶中形成腺泡并且不表达 BGP，当用 BGP 有义基因转染并在基质胶中生长时，这些细胞表现出大量细胞死亡和偶尔形成腺泡。为了描述 BGP 管腔形成的分子决定因素，我们建议（1）。 ）研究 MCF7 细胞中阻止其恢复为更“正常”表型的缺陷，（2）绘制细胞骨架与 BGP 细胞质结构域的相互作用，（3）分析负责管腔形成的 BGP 胞外域的顺反二聚体相互作用，以及 (4) 确定 MCF10F 和 MCF7 细胞中 BGP 基因的调节。 此外，我们发现MCF10F细胞产生的肌上皮细胞可以富集，并且显示为BGP阴性，并且能够诱导CEA（癌胚抗原），这是乳腺癌细胞的标志。 我们还将研究这些细胞中CEA和BGP基因的调控，以深入了解乳腺癌的肿瘤发生过程。