Adhesion signaling by a novel mitotic substrate of src

src 新型有丝分裂底物的粘附信号传导

• 批准号: 7047948
• 负责人: Mark M Moasser
• 金额: $ 26.3万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7047948
• 关键词: antibody; athymic mouse; biological signal transduction; breast neoplasms; cell adhesion; cell cycle; clinical research; endopeptidases; enzyme mechanism; gene expression; genetically modified animals; glycoproteins; human tissue; laboratory rabbit; metastasis; molecular oncology; neoplasm /cancer invasiveness; neoplastic growth; oncogenes; phosphorylation; protein protein interaction; protein structure function; protein tyrosine kinase; xenotransplantation

DESCRIPTION (provided by applicant): Src kinases are activated in a number of human tumors but the mechanism by which they mediate their oncogenic functions remains unkown. We have searched for cell cycle substrates of src family kinases and purified and cloned a novel protein that undergoes tyrosine phosphorylation during the mitotic phase by src and yes. This protein, named Trask (Transmembrane and Associated with Src Kinases), is a 140kd transmembrane glycoprotein seen only in more complex organisms. It has little homology to currently known protein families and no functionally revealing sequence motifs. Tet-inducible overexpression of Trask in MDA-468 breast cancer cells leads to a loss-of-adhesion phenotype and, consistent with a function in cell adhesion, Trask interacts with a number of membrane and extracellular matrix metallo and serine proteases, cadherins, syndecans, and fibronectin. Trask is unique among adhesion molecules in that it is under cell cycle regulation. We hypothesize that the mitotic phosphorylation of Trask regulates the transient loss of adhesion seen in epithelial cells undergoing mitosis, and that hyper-phosphorylation or inappropriate interphase phosphorylation of Trask by activated src kinases in tumors leads to aberrant cell detachment and development of a metastatic phenotype. In this proposal, we seek to test our hypothesis. In aim 1 we will determine whether Trask phosphorylation and interaction with extracellular proteases and adhesion proteins regulates cell adhesion and whether the phosphorylation and protease binding activities of Trask are normally restricted to the mitotic phase in epithelial cells. In aim 2 we will determine whether overexpression of Trask in experimental xenograft tumors increases their metastatic rate, and by studying Trask expression in early and metastatic human tumors we will determine whether this reflects the biology of naturally occurring human cancers. In aim 3, we will determine whether metastases can be averted in the src-driven polyoma mT transgenic model of metastatic breast cancer by inactivation of the Trask gene. Our hypothesis, if confirmed, will profoundly improve our understanding of the molecular basis for tumor metastases and reveal the oncogenic role of src kinases, and lead to therapeutic strategies to prevent this lethal complication of cancer.

描述（由申请人提供）：Src 激酶在许多人类肿瘤中被激活，但它们介导致癌功能的机制仍然未知。我们寻找了 src 家族激酶的细胞周期底物，并纯化并克隆了一种新的蛋白质，该蛋白质在有丝分裂期通过 src 和 yes 进行酪氨酸磷酸化。这种蛋白质被命名为 Trask（跨膜并与 Src 激酶相关），是一种仅在更复杂的生物体中可见的 140kd 跨膜糖蛋白。它与目前已知的蛋白质家族几乎没有同源性，并且没有功能上揭示的序列基序。 MDA-468 乳腺癌细胞中 Tet 诱导的 Trask 过度表达导致粘附丧失表型，并且与细胞粘附功能一致，Trask 与许多膜和细胞外基质金属和丝氨酸蛋白酶、钙粘蛋白、多配体相互作用和纤连蛋白。 Trask 在粘附分子中是独一无二的，因为它受到细胞周期的调节。我们假设 Trask 的有丝分裂磷酸化调节经历有丝分裂的上皮细胞中观察到的短暂的粘附丧失，并且肿瘤中激活的 src 激酶对 Trask 的过度磷酸化或不适当的间期磷酸化导致异常细胞脱离和转移表型的发展。在这个提案中，我们试图检验我们的假设。在目标 1 中，我们将确定 Trask 磷酸化以及与细胞外蛋白酶和粘附蛋白的相互作用是否调节细胞粘附，以及 Trask 的磷酸化和蛋白酶结合活性通常是否仅限于上皮细胞的有丝分裂期。在目标 2 中，我们将确定实验性异种移植肿瘤中 Trask 的过度表达是否会增加其转移率，并且通过研究早期和转移性人类肿瘤中的 Trask 表达，我们将确定这是否反映了自然发生的人类癌症的生物学特性。在目标 3 中，我们将确定是否可以通过 Trask 基因失活来避免 src 驱动的转移性乳腺癌多瘤 mT 转基因模型中的转移。我们的假设如果得到证实，将深刻提高我们对肿瘤转移分子基础的理解，揭示 src 激酶的致癌作用，并制定预防这种致命癌症并发症的治疗策略。