Biased chemokine receptor signaling in cancer progression

项目摘要 胰腺癌是一种致命的癌症，患者很少能在两年后存活。 由于明显的转移、免疫抑制和逃避、结缔组织增生和 不受抑制的肿瘤增殖共同赋予治疗抗性。肿瘤转移潜能 由G蛋白偶联趋化因子受体CXCR4介导。趋化因子CXCL12是 CXCR4的同源配体，是肿瘤中两种基质细胞产生的免疫介质 微环境和转移目的地的正常细胞。虽然大量的报告 CXCR4表达升高，在许多癌症中具有促肿瘤发生作用， CXCR4和CXCL12在胰腺癌非转移途径中的机制作用 进展仍然知之甚少。我们公布的令人兴奋的初步数据显示， CXCL12促进或抑制肿瘤进展和转移的新机制 基于其激活CXCR4作为单体或二聚体的能力。为了确定 CXCR4介导的癌症进展背后的机制，我们已经设计了一个锁定的单体， CXCL12的一种变体，作为CXCR4的平衡激动剂，激活其整个G蛋白 和β-抑制蛋白信号系统，以及一个锁定的二聚体偏向激动剂变体， 只是一个子集。我们假设CXCR4的偏向性信号传导阻止了肿瘤迁移， 同时从骨髓和肿瘤外周吸引细胞毒性T淋巴细胞， 渗透进肿瘤杀死癌细胞该提案的总体目标是利用偏性激动剂 作为一种多管齐下的抗肿瘤方法来消除胰腺癌的进展。要求1 将使用胰腺癌的基因工程小鼠模型来分析 在肿瘤进展中的偏向激动剂信号传导。目标2将使用转基因小鼠模型和细胞 培养方法来研究偏置信号对免疫细胞的影响， 在肿瘤微环境中的运输、浸润和肿瘤细胞杀伤。目标3将深入研究 CXCL 12激动剂与CXCR 4受体之间的氨基酸水平相互作用，以确定 负责抗肿瘤配体偏向和组织偏向信号传导的机制。的整体影响 的拟议工作是，我们将揭示一个有针对性的结构和生化偏见激动剂 CXCL12和CXCR4在癌症中的多效性作用的信号传导机制。

Project Summary Pancreatic cancer is a uniformly lethal form of cancer with patients rarely surviving two years after diagnosis due to pronounced metastasis, immune suppression and evasion, desmoplasia, and unchecked tumor proliferation that together confer therapeutic resistance. Cancer metastatic potential is mediated by the G protein-coupled chemokine receptor CXCR4. The chemokine CXCL12 is the cognate ligand for CXCR4 and is an immune mediator produced by both stromal cells in the tumor microenvironment and normal cells at metastatic destinations. While a wealth of reports attribute elevated CXCR4 expression with pro-tumorigenic effects in numerous cancers, the precise mechanistic roles for CXCR4 and CXCL12 in non-metastatic pathways of pancreatic cancer progression remain poorly understood. Our published and exciting preliminary data have revealed a novel mechanism whereby CXCL12 can either promote or inhibit tumor progression and metastasis based on its ability to activate CXCR4 as a monomer or dimer. In pursuit of determining the mechanism behind CXCR4-mediated cancer progression, we have engineered a locked monomer variant of CXCL12 that acts as a balanced agonist at CXCR4, activating the entirety of its G protein and -arrestin signaling repertoire, as well as a locked dimer biased agonist variant which activates only a subset. We hypothesize that biased signaling at CXCR4 prevents tumor migration and progression while attracting cytotoxic T lymphocytes from the bone marrow and tumor periphery to infiltrate the tumor and kill cancer cells. The overall goal of this proposal is to harness biased agonist signaling as a multi-pronged anti-tumor approach to abrogate pancreatic cancer progression. Aim 1 will use genetically engineered mouse models of pancreatic cancer to analyze the in vivo influence of biased agonist signaling in tumor progression. Aim 2 will use transgenic mouse models and cell culture approaches to investigate the sparsely-studied effects of biased signaling on immune cell trafficking, infiltration, and tumor cell killing in the tumor microenvironment. Aim 3 will delve into the amino-acid level interactions between CXCL12 agonists with CXCR4 receptor to determine the mechanisms responsible for anti-tumor ligand biased and tissue biased signaling. The overall impact of the proposed work is that we will reveal a targetable structural and biochemical biased agonist signaling mechanism that explains the pleiotropic effects of CXCL12 and CXCR4 in cancer.