G Proteins and Their Receptors in Tumor Cell Metastasis

描述(由申请人提供)：转移涉及与细胞运动有关的不同蛋白的表达，以及归巢受体、它们的配体和细胞外基质降解蛋白。最近的研究发现，溶血磷脂酸(LPA)调控的信号通路在卵巢细胞的生长和转移中起着关键作用。根据我们的初步发现，G？13(可以被LPA激活)和HAX-1相互作用是细胞运动所必需的，我们假设G？13-HAX-1-Cortactin相互作用在LPA反应性卵巢癌细胞的转移中起关键作用。这一假设将在以下具体目标下进行检验：目标1：G？13-HAX-1相互作用的特征。通过定点突变方法确定HAX-1与G？13和皮质酮的相互作用位点；目标2：分析G？13-HAX-1-皮质酮复合体。将确定HAX-1、G？13、Cortactin和Rac在形成四元复合体中的相互关系以及HAX-1和G？13在皮质肌动蛋白磷酸化中的作用；目标3：分析其他HAx-1相互作用的信号成分。目的4：HAX-1对G？13-HAX-1致癌活性的影响：我们将探讨G？13-HAX-1是否参与卵巢癌细胞的肿瘤生长；以及目标5：G？13-HAX在肿瘤细胞迁移和转移中的作用。使用波士顿马萨诸塞州总医院的Sandra Orsulic(Co-P.I)博士开发的新型小鼠模型系统，将分析HAX-1或G？13在卵巢癌细胞迁移和侵袭潜力中的作用。我们希望，通过识别与肿瘤细胞运动有关的信号基因，将为治疗干预定义新的靶点。

DESCRIPTION (provided by applicant): Metastasis involves the expression of different proteins involved in cell motility along with homing receptors, their ligands, and extracellular matrix degrading proteases. Recent studies have identified that the signaling pathways regulated by lysophosphatidic acid (LPA) play a critical role in ovarian cell growth and metastasis. Based on our preliminary findings that G?13 (which can be activated by LPA) and Hax-1 interaction is required for cell motility, we hypothesize here that G?13-HAX-1-cortactin interaction is critically involved in the metastasis of LPA-responsive ovarian cancer cells. This hypothesis will be tested under the following specific aims: Aim 1: Characterization of G?13-Hax-1 interaction. Hax-1 interaction sites with G?13 and cortactin will be defined by site-directed mutagenesis approach; Aim 2: Analysis of G?13-Hax-1-cortactin complex. The interrelationship of Hax-1, G?13, Cortactin, and Rac in forming the quadnary complex and the role of Hax-1 and G?13 in cortactin-phosphorylation will be defined; Aim 3: Analysis of other Hax-1 interacting signaling components. The target pathways regulated by G?13-Hax-1 complex will be identified by the analysis for specific GEFs and regulation of uPA and/or MMP2; Aim 4: Effect of Hax-1 on the oncogenic activity of G?13: We will investigate whether G?13-Hax-1 association is involved in neoplastic growth of ovarian cancer cells; and Aim 5: Role of G?13-Hax in tumor cell migration and metastasis. The role of Hax-1 or G?13 on the migration and invasive potentials of ovarian cancer cells will be analyzed using the novel mouse model system developed by Dr. Sandra Orsulic (Co-P.I) at Massachusetts General Hospital, Boston. We hope that the identification of a signaling locus involved in tumor cell motility, as proposed here, will define newer targets for therapeutic intervention.