Regulation of Nutrient Stress-Induced Macropinocytosis in Pancreatic Ductal Adenocarcinoma

胰腺导管腺癌中营养应激诱导的巨胞饮作用的调节

• 批准号: 10677661
• 负责人: Cosimo Commisso
• 金额: $ 45.68万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10677661
• 关键词: Acceleration; Actins; Amino Acids; Animal Model; Biological Models; Bypass; Cancer Etiology; Cell Proliferation; Cell Survival; Cells; Cessation of life; Consumption; Cytoskeleton; Data; Development; Disease; EGFR inhibition; Ecosystem; Enzymes; Epidermal Growth Factor Receptor; Evaluation; Extracellular Protein; Funding; Gene Expression; Glutamine; Growth; Human; In Vitro; Ligands; Liquid substance; Malignant Neoplasms; Metabolic; Metabolic stress; Metabolism; Microtubules; Modality; Molecular; Norleucine; Normal tissue morphology; Nutrient; Oncogenes; Pancreatic Ductal Adenocarcinoma; Pathway interactions; Phosphorylation; Phosphotransferases; Play; Process; Production; Proliferating; Proteins; Reaction; Regulation; Research; Role; Route; Signal Transduction; Small Interfering RNA; Source; Specimen; Starvation; Strategic Planning; Stress; Testing; Tumor Suppressor Proteins; United States; Work; analog; atypical protein kinase C; cancer cell; cancer therapy; cell growth; deprivation; experimental study; glutamine analog; in vivo; knock-down; mimetics; mimicry; neoplastic cell; new therapeutic target; novel; novel therapeutics; pancreatic ductal adenocarcinoma cell; pancreatic ductal adenocarcinoma model; response; stress tolerance; tumor; tumor growth; tumor microenvironment; uptake

PROJECT SUMMARY Recent years have witnessed a growing appreciation of the role that metabolic reprogramming plays in conferring growth and survival advantages to tumor cells. Of particular relevance to this proposal is the now widely accepted notion that pancreatic ductal adenocarcinoma (PDAC) cells depend on macropinocytosis as an amino acid supply route. By stimulating the uptake of extracellular protein and targeting it for lysosomal degradation, the macropinocytosis pathway provides cancer cells with a source of protein-derived amino acids, allowing tumors to circumvent amino acid depletion and survive nutrient stress. Glutamine is a vital nutrient to tumors as it supports the metabolic reactions necessary to sustain tumor cell growth; however, hearty consumption by the tumor often leads to a glutamine-depleted tumor ecosystem. Our previously funded research demonstrated that glutamine depletion in PDAC tumors has the capacity to modulate macropinocytosis – dialing the process up or down as required. We attributed this inducible form of macropinocytic uptake to the activation of EGFR-Pak signaling. Interestingly, we have found that macropinocytosis is also induced by a glutamine structural analog that broadly suppresses glutamine metabolism; however, uptake in this setting does not employ EGFR signaling. Since the inhibition of glutamine metabolism is being actively pursued as a therapy for cancer, we set out to decipher how glutamine mimicry might elicit macropinocytosis as an adaptive response. We performed a high- throughput siRNA screen and identified the atypical protein kinase C (aPKC) subfamily of kinases, PKCι and PKCζ, as the most potent regulators of uptake. This proposal is based on our preliminary data demonstrating that knockdown of either PKCι or PKCζ not only suppresses macropinocytosis caused by glutamine analogs, but also abrogates uptake caused by glutamine starvation, suggesting that the aPKCs are general modulators of nutrient stress-induced macropinocytosis. Based on these data, our central hypothesis is that aPKC signaling is integral to nutrient stress-driven macropinocytosis and that the aPKCs support metabolic stress tolerance in PDAC tumors. We will 1) examine the molecular mechanisms underlying the role of aPKCs in nutrient stress- driven macropinocytosis and 2) determine the functional consequences of suppressing aPKC-dependent macropinocytosis in PDAC. This project constitutes the first evaluation of the role that the aPKCs play in the modulation of macropinocytosis and the first to interrogate aPKC function from the perspective of glutamine supply. Moreover, because our work will establish aPKC-dependent macropinocytosis as a critical metabolic adaptation in response to glutamine mimetics, our findings could have tremendous impact on the development of novel therapeutic modalities for PDAC.

项目总结 近年来，人们越来越多地认识到新陈代谢重新编程在授予 有利于肿瘤细胞的生长和存活。与这项提议特别相关的是现在被广泛接受的 胰腺导管癌细胞(PDAC)依赖巨噬细胞吞噬作为一种氨基酸的概念 补给路线。通过刺激细胞外蛋白的摄取并将其靶向于溶酶体的降解， 巨噬细胞吞噬途径为癌细胞提供了蛋白质衍生的氨基酸来源，从而使肿瘤 避免氨基酸的消耗，并在营养压力下生存。谷氨酰胺是肿瘤的重要营养物质，因为它 支持维持肿瘤细胞生长所需的代谢反应；然而， 肿瘤通常会导致谷氨酰胺耗尽的肿瘤生态系统。我们之前资助的研究表明 PDAC肿瘤中谷氨酰胺的耗竭具有调节巨噬细胞吞噬的能力--使这一过程向上或向上 根据需要向下。我们将这种可诱导形式的巨噬细胞摄取归因于EGFR-Pak的激活 发信号。有趣的是，我们发现谷氨酰胺结构类似物也能引起巨噬细胞增多。 这在很大程度上抑制了谷氨酰胺代谢；然而，这种情况下的摄取不使用EGFR信号。 由于抑制谷氨酰胺代谢被积极用作癌症的治疗方法，我们着手 破译谷氨酰胺模拟如何引起巨饮细胞增多作为一种适应性反应。我们表演了一场高潮- 吞吐量siRNA筛选并鉴定了非典型蛋白激酶C亚家族的蛋白激酶C、蛋白激酶Cι和 PKCζ作为最有效的摄取调节因子。这一建议是基于我们的初步数据证明的 PKCι或PKCζ的敲除不仅能抑制谷氨酰胺类似物引起的巨噬细胞吞噬作用， 但也取消了谷氨酰胺饥饿引起的摄取，表明apkcs是一般的调节器。 营养应激引起的巨噬细胞增多症。基于这些数据，我们的中心假设是aPKC信号 是营养应激驱动的巨噬细胞吞噬所必需的，并且apkcs支持代谢应激耐受。 PDAC肿瘤。我们将1)研究apkcs在营养胁迫中作用的分子机制- 驱动巨噬细胞吞噬和2)确定抑制aPKC依赖的功能后果 PDAC中的巨噬细胞增多。该项目是对联合国儿童基金会在以下领域所发挥作用的首次评价 巨噬细胞吞噬的调节及首次从谷氨酰胺角度探讨蛋白激酶C的功能 供给。此外，因为我们的工作将建立依赖PKC的巨噬细胞吞噬作为一种关键的代谢 适应对谷氨酰胺模拟物的反应，我们的发现可能会对发育产生巨大影响 对PDAC的新的治疗方式。