Biased chemokine receptor signaling in cancer progression

项目摘要 胰腺癌是一种完全致命的癌症，患者很少能在两年后存活。 诊断为明显转移、免疫抑制和逃避、结缔组织增生症和 不受抑制的肿瘤增殖，共同产生治疗耐药性。肿瘤转移潜能 是由G蛋白偶联趋化因子受体CXCR4介导的。趋化因子CXCL12是 CXCR4的同源配体，是肿瘤中两种间质细胞产生的免疫介质 转移靶点的微环境和正常细胞。而丰富的报告属性 在许多癌症中，CXCR4表达升高与促肿瘤作用密切相关 CXCR4和CXCL12在胰腺癌非转移途径中的作用机制 进展情况仍然知之甚少。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 基于其作为单体或二聚体激活CXCR4的能力。在追求确定 CXCR4介导的癌症进展背后的机制，我们设计了一种锁定的单体 CXCL12的变种，作为CXCR4的平衡激动剂，激活其全部G蛋白 和-arrestin信号转导谱系，以及锁定的二聚体偏向激动剂变体，激活 只有一个子集。我们假设CXCR4上的偏向信号阻止肿瘤迁移和 在吸引来自骨髓和肿瘤周围的细胞毒性T淋巴细胞的同时进展 渗入肿瘤并杀死癌细胞。这项提案的总体目标是利用有偏见的激动剂 作为一种多管齐下的抗肿瘤方法来消除胰腺癌进展的信号。目标1 将利用基因工程小鼠胰腺癌模型分析其对体内的影响 肿瘤进展中的偏向激动剂信号。AIM 2将使用转基因小鼠模型和细胞 研究偏向信号对免疫细胞影响的培养方法 在肿瘤微环境中的运输、渗透和肿瘤细胞杀伤。《目标3》将深入探讨 CXCL12激动剂与CXCR4受体的氨基酸水平相互作用 抗肿瘤配基偏向和组织偏向信号的机制。总体影响 我们将揭示一种有针对性的结构和生化偏向激动剂 解释CXCL12和CXCR4在癌症中的多效性作用的信号机制。

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.