Metabolism of Extracellular Matrix Supports Pancreatic Cancer Growth

项目总结 在所有主要癌症中，胰腺导管腺癌(PDA)的五年存活率最低。杀伤力 动脉导管未闭的主要原因是缺乏有效的治疗选择。PDA治疗的一个主要障碍是 肿瘤微环境，主要由致密的纤维炎性间质反应组成。基质是 主要由免疫细胞和癌症相关成纤维细胞(CAF)填充。CAF广泛沉积在细胞外 基质成分，包括高度透明质酸(HA)。HA是一种无处不在的亲水性碳水化合物 聚合物。PDA肿瘤中高水平的HA会保留水分，导致组织间的超生理压力。这个 高压会破坏血管系统，限制药物的渗透，限制氧气和营养的可获得性。 为了在严酷的微环境中维持生存能力，癌细胞通过突变进行代谢重新编程。 KRAS，PDA中的标志性转化癌基因。突变体Kras增强通过氨基己糖的通量 调节限速酶谷氨酰胺-6-磷酸果糖的生物合成途径 转氨酶(GFAT)。HBP是一种高度保守的整合葡萄糖和谷氨酰胺的途径 新陈代谢。此外，HBP是糖基化底物从头合成的唯一途径。因此， HBP是治疗PDA的一个有吸引力的靶点。 与这一必要的作用相反，我的初步数据显示，HBP不是一种有效的治疗靶点 活着。相反，我发现癌细胞能够利用HA，一种碳水化合物聚合物，为HBP提供燃料和支持 独立于其活动的增长。我的数据表明，癌细胞实现这一目标的方法之一是利用 N-乙酰氨基葡萄糖(GlcNAc)通过GlcNAc回收途径从HA中释放出来。这些数据表明，HA是一种新的营养素 癌细胞的来源。他们还指出了癌细胞为了生存而经历的一种新的新陈代谢重新编程 并在缺乏营养的肿瘤微环境中增殖。 这一建议的工作假设是，CAF通过释放GlcNAc作为HA来支持PDA代谢。 这将分两部分进行研究。第一，涉及遗传和药物抑制的机制研究 将进行CAF合成HA和癌细胞摄取HA；靶向的功能后果 这些特征将在体外和体内确定(具体目标1)。第二，涉及基因的机制研究 抑制HA分解代谢和GlcNAc挽救途径；类似地，功能 靶向这些途径的后果将在体外和体内确定(特定目标2)。体外研究 将在患者来源的CAF和人类PDA细胞系上进行。此外，我还将演示 这一途径使用原位联合注射体内研究转基因CAF和PDA细胞。这 该提案旨在从功能和机械上定义一种新的代谢重连，它可以识别新的 掌上电脑治疗靶点S。

PROJECT SUMMARY Pancreatic ductal adenocarcinoma (PDA) has the worst five-year survival rate of any major cancer. The lethality of PDA is largely due to lack of effective treatment options. A major obstacle in PDA treatment is conferred by the tumor microenvironment, composed mainly of dense fibroinflammatory stromal response. The stroma is populated mainly by immune cells and cancer-associated fibroblasts (CAF). CAFs deposit extensive extracellular matrix components, including a high degree of hyaluronic acid (HA). HA is a ubiquitous, hydrophilic carbohydrate polymer. The high HA levels in PDA tumors retain water, leading to supraphysiological interstitial pressure. The high pressure collapses the vasculature, limiting drug penetrance, and oxygen and nutrient availability. To sustain viability in the austere microenvironment, cancer cells undergo metabolic reprogramming via mutant Kras, the signature transforming oncogene in PDA. Mutant Kras enhances flux through the hexosamine biosynthesis pathway (HBP) by regulating the rate-limiting enzyme glutamine-fructose 6-phosphate transamidase (GFAT). The HBP is a highly conserved pathway that integrates glucose and glutamine metabolism. In addition, the HBP is the only way to synthesize glycosylation substrate de novo. Therefore, the HBP represents an attractive therapeutic target in PDA. In contrast to this necessary role, my preliminary data show that the HBP is not an effective therapeutic target in vivo. Rather, I found that cancer cells are able to utilize HA, a carbohydrate polymer, to fuel the HBP and support growth independent of its activity. My data illustrate that one of the ways cancer cells achieve this is by utilizing N-acetyl-glucosamine (GlcNAc) from HA via GlcNAc salvage pathway. The data implicate HA as a novel nutrient source for cancer cells. They also point to a novel metabolic reprogramming that cancer cells undergo to survive and proliferate in the nutrient-poor tumor microenvironment. The working hypothesis of this proposal is that CAFs support PDA metabolism via the release of GlcNAc as HA. This will be examined in two parts. First, mechanistic studies involving genetic and pharmacological inhibition of HA synthesis by CAF and HA uptake by cancer cells will be performed; functional consequences of targeting these features will be defined in vitro and in vivo (Specific Aim 1). Second, mechanistic studies involving genetic inhibition of HA catabolism and GlcNAc salvage pathway will be performed; similarly, the functional consequences of targeting these pathways will be defined in vitro and in vivo (Specific Aim 2). The in vitro studies will be performed on a patient-derived CAF and human PDA cell lines. Further, I will demonstrate the role for this pathway using orthotopic co-injection in vivo studies with genetically-modified CAF and PDA cells . This proposal aims to functionally and mechanistically define a novel metabolic rewiring, which can identify a new therapeutic target(s) for PDA.