Bi-directional regulation of chemokine receptor signaling

项目摘要 宫颈癌仍然是世界范围内癌症相关死亡的主要原因之一。大量的 有证据表明G蛋白偶联受体（GPCR）的一个亚家族，称为趋化因子受体， 与包括宫颈癌在内的几种癌症的进展有关。某些信号传导失调 趋化因子受体与宫颈癌预后不良相关，但其机制尚不清楚 明白这项提案的总体目标是确定趋化因子的调控机制， 受体调节在宫颈癌生长和转移的背景下。这一点很重要，因为这些 研究将确定临床潜力的新靶点。具体地说，我们将重点关注一个新的范式， 趋化因子受体通过A激酶锚定蛋白（AKAP）双向调节。AKAP是脚手架 蛋白质结合和核多个蛋白质，通常属于一个共同的信号通路，空间 并在时间上控制信号以驱动生理反应。我们对AKAP进行了siRNA筛选， 在宫颈癌细胞系HeLa细胞中表达，并提供了AKAP参与交叉- 趋化因子受体运输的调节。此外，使用生物化学和生物物理方法， 提供了趋化因子受体与AKAP和蛋白激酶C（PKC）存在于一个区室中的证据， 但是排除了其他GPCR。趋化因子受体可能共同存在于一个亚细胞中， 在质膜上的隔室，使它们能够交叉调节，而不需要来自其他GPCR的输入， 可能专门微调它们的信号。根据已发表的和新的初步数据，我们假设， 趋化因子受体是由AKAP分隔的多聚体蛋白复合物的一部分， 双向调节。为了验证这一假设，我们将追求三个具体目标。目标1：确定 PKC在双向趋化因子受体调节中的作用;目的2：确定AKAP在 目的3：确定趋化因子受体双向运输和信号传导的作用， 子宫颈癌中趋化因子受体的调节。在拟议的研究结束时 我们期望确定趋化因子受体信号传导的双向调节机制。 重要的是，我们希望建立趋化因子受体调节和信号传导的新方面， 治疗宫颈癌的药物。

PROJECT SUMMARY Cervical cancer remains one of the leading causes of cancer-related deaths world-wide. A large body of evidence indicates that a sub-family of G protein-coupled receptors (GPCRs), known as chemokine receptors, are linked to progression of several cancers, including cervical cancer. Dysregulated signaling of certain chemokine receptors correlates with poor prognosis in cervical cancer, yet the mechanisms remain poorly understood. The overall objective of this proposal is to determine the mechanisms governing chemokine receptor regulation in the context of cervical cancer growth and metastasis. This is significant because these studies will define new targets for clinical potential. Specifically, we will focus on a novel paradigm that governs chemokine receptor bi-directional regulation by A kinase anchoring proteins (AKAPs). AKAPs are scaffolding proteins that bind and nucleate multiple proteins, usually belonging to a common signaling pathway, to spatially and temporally control signaling to drive physiological responses. We performed a siRNA screen of AKAPs expressed in HeLa cells, a cervical cancer cell line, and provide evidence that AKAPs are involved in cross- regulation of chemokine receptor trafficking. Further, using biochemical and biophysical approaches we provide evidence that chemokine receptors reside in a compartment with AKAPs and protein kinas C (PKC), but that other GPCRs are excluded. It is possible that chemokine receptors might co-reside in a sub- compartment at the plasma membrane that enables their cross-regulation without input from other GPCRs, likely to exclusively fine tune their signaling. Based on published and new preliminary data we hypothesize that chemokine receptors are part of a multimeric protein complex compartmentalized by AKAPs that governs their bi-directional regulation. To test this hypothesis we will pursue three specific aims. Aim 1: To determine the role of PKC in bi-directional chemokine receptor regulation; Aim 2: To determine the role of AKAPs in chemokine receptor bi-directional trafficking and signaling; and Aim 3: To determine the role of bi-directional chemokine receptor regulation in cervical cancer in vitro and in vivo. At the conclusion of the proposed studies we expect to determine the mechanism of bi-directional regulation of chemokine receptor signaling. Importantly, we expect to establish that novel aspects of chemokine receptor regulation and signaling could be targeted to treat cervical cancer.