Signaling Mechanisms of EphrinB1 in Cell Adhesion, Migration and Invasion

EphrinB1 在细胞粘附、迁移和侵袭中的信号机制

• 批准号: 8349247
• 负责人: Ira Daar
• 金额: $ 66.21万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8349247
• 关键词: Adhesions; Affect; Biochemical; Biological Models; Breast; Cancer cell line; Cell Adhesion; Cell Fate Control; Cell Line; Cell Lineage; Cell Polarity; Cell physiology; Cell-Cell Adhesion; Cells; Colon; Complex; Data; Development; Developmental Process; Disease; Disseminated Malignant Neoplasm; Distal; Embryo; Embryonic Development; Environment; Eph Family Receptors; Ephrins; Epithelial Cells; Event; Family; Family member; Fibroblast Growth Factor Receptors; Histologic; Human; Intercellular Junctions; Investigation; Laboratories; Ligands; Malignant Neoplasms; Maps; Mediating; Monomeric GTP-Binding Proteins; Morphogenesis; Movement; Neoplasm Metastasis; Neuroblastoma; Ovarian; Pathway interactions; Play; Process; Prostate; Protein Tyrosine Kinase; Proteins; Rana; Receptor Protein-Tyrosine Kinases; Research; Role; Scaffolding Protein; Signal Transduction; Signal Transduction Pathway; Signaling Molecule; System; Therapeutic Intervention; Tight Junctions; Tissues; Tyrosine Phosphorylation; Visual Fields; Work; Xenopus; Xenopus oocyte; angiogenesis; cell motility; improved; insight; intercellular communication; interest; loss of function; lung melanoma; member; migration; mutant; neoplastic; protein complex; receptor; research study; retinal progenitor cell; tumorigenesis

Our current research interests are aimed toward examining the mechanism by which Eph receptor tyrosine kinases and their ephrin ligands signal events affecting cell-cell adhesion and morphogenetic movements. From the elucidation of these signal transduction pathways we may improve our understanding of oncogenesis. The cell-cell adhesion system plays a major role in normal development and morphogenesis. Inactivation of this adhesion system is thought to play a critical role in cancer invasion and metastasis. The Xenopus embryo is well suited for investigations of these processes because the frog has a well characterized and invariant cell fate map and cell lineage can be easily traced during experiments. Mutant receptors, ligands, and other proteins can be ectopically expressed in embryos. Thus, their effects on signal transduction, motility, and differentiation can be assessed morphologically and histologically as well as biochemically in a developing vertebrate. Our laboratory is currently investigating the role of the Xenopus Eph receptor tyrosine kinases and ephrinB transmembrane ligands in cell signaling and function using the Xenopus oocyte and embryo systems, as well as human cultured cell lines. At present, our emphasis is placed upon the mechanism by which these Eph family members send signals affecting morphogenetic movements. Members of the Eph family have been implicated in regulating numerous developmental processes and have been found to be de-regulated in metastatic cancers, for example, prostate, ovarian, breast, colon, neuroblastoma, lung, and melanoma. Our laboratory has continued these studies examining proximal and distal signaling from ephrinB1 that controls cell adhesion and cell movement. We recently found evidence that ephrinB1 signals via its intracellular domain to control retinal progenitor movement into the eye field by interacting with Dishevelled (dsh), and co-opting the planar cell polarity (PCP) pathway. Using biochemical analysis and gain or loss of function experiments, our data suggest that dsh associates with ephrinB1 and mediates ephrinB1 signaling via downstream members of the PCP pathway during eye field formation. thus, we have used the eye field as a model system for understanding how ephrinB1 controls cell movement. Most recently we have examined the mechanisms by which ephrinB1 affects cell-cell junctions. A body of evidence is emerging that shows a requirement for ephrin ligands in the proper migration of cells, and the formation of cell and tissue boundaries. These processes are dependent on the cellcell adhesion system, which plays a crucial role in normal morphogenetic processes during development, as well as in invasion and metastasis19. Although ephrinB ligands are bi-directional signalling molecules, the precise mechanism by which ephrinB1 signals through its intracellular domain to regulate cell-cell adhesion in epithelial cells remains unclear. Here, we present evidence that ephrinB1 associates with the Par polarity complex protein Par-6 (a scaffold protein required for establishing tight junctions) and can compete with the small GTPase Cdc42 for association with Par-6. This competition causes inactivation of the Par complex, resulting in the loss of tight junctions. Moreover, the interaction between ephrinB1 and Par-6 is disrupted by tyrosine phosphorylation of the intracellular domain of ephrinB1. Thus, we have identified a mechanism by which ephrinB1 signalling regulates cell-cell junctions in epithelial cells, and this may influence how we devise therapeutic interventions regarding these molecules in metastatic disease.

我们目前的研究兴趣旨在研究 Eph 受体酪氨酸激酶及其肝配蛋白配体发出影响细胞间粘附和形态发生运动的信号事件的机制。通过阐明这些信号转导途径，我们可以提高对肿瘤发生的理解。细胞-细胞粘附系统在正常发育和形态发生中起着重要作用。这种粘附系统的失活被认为在癌症侵袭和转移中发挥着关键作用。非洲爪蟾胚胎非常适合研究这些过程，因为青蛙具有特征明确且不变的细胞命运图谱，并且在实验过程中可以轻松追踪细胞谱系。突变受体、配体和其他蛋白质可以在胚胎中异位表达。因此，它们对信号转导、运动和分化的影响可以在发育中的脊椎动物中从形态学、组织学以及生化方面进行评估。 我们的实验室目前正在使用非洲爪蟾卵母细胞和胚胎系统以及人类培养细胞系研究非洲爪蟾 Eph 受体酪氨酸激酶和 ephrinB 跨膜配体在细胞信号传导和功能中的作用。目前，我们的重点是这些 Eph 家族成员发送影响形态发生运动的信号的机制。 Eph 家族成员参与调节许多发育过程，并被发现在转移性癌症中失调，例如前列腺癌、卵巢癌、乳腺癌、结肠癌、神经母细胞瘤、肺癌和黑色素瘤。我们的实验室继续进行这些研究，检查 ephrinB1 控制细胞粘附和细胞运动的近端和远端信号传导。我们最近发现证据表明，ephrinB1 通过其细胞内结构域发出信号，通过与 Disheveled (dsh) 相互作用并选择平面细胞极性 (PCP) 途径来控制视网膜祖细胞移动到眼部区域。通过生化分析和功能获得或丧失实验，我们的数据表明 dsh 与 ephrinB1 结合，并在眼场形成过程中通过 PCP 通路的下游成员介导 ephrinB1 信号传导。因此，我们使用眼场作为模型系统来了解 ephrinB1 如何控制细胞运动。最近，我们研究了 ephrinB1 影响细胞与细胞连接的机制。大量证据表明，细胞的正确迁移以及细胞和组织边界的形成需要肝配蛋白配体。这些过程依赖于细胞粘附系统，该系统在发育过程中的正常形态发生过程以及侵袭和转移中发挥着至关重要的作用19。尽管 ephrinB 配体是双向信号分子，但 ephrinB1 通过其胞内结构域发出信号以调节上皮细胞中细胞间粘附的精确机制仍不清楚。在这里，我们提供的证据表明 ephrinB1 与 Par 极性复合蛋白 Par-6（建立紧密连接所需的支架蛋白）结合，并且可以与小 GTPase Cdc42 竞争与 Par-6 的结合。这种竞争会导致 Par 复合物失活，从而导致紧密连接的丧失。此外，ephrinB1 胞内结构域的酪氨酸磷酸化会破坏 ephrinB1 和 Par-6 之间的相互作用。因此，我们已经确定了 ephrinB1 信号传导调节上皮细胞中细胞-细胞连接的机制，这可能会影响我们如何设计针对转移性疾病中这些分子的治疗干预措施。