Mechanistic insights into lysosomal nutrient efflux in cancer

癌症中溶酶体营养物流出的机制见解

• 批准号: 10682652
• 负责人: Kacper Rogala
• 金额: $ 24.9万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10682652
• 关键词: Affect; Amino Acids; Area; Arginine; Autophagocytosis; Binding; Biochemical; Biological Assay; Biology; Cell physiology; Chemicals; Choking; Coupled; Cryoelectron Microscopy; Cytosol; Cytotoxic Chemotherapy; DNA; Development; Eating; Environment; Essential Amino Acids; Extracellular Protein; Face; Food; Future; Gatekeeping; Goals; Growth; Human; Impairment; In Vitro; Institutes; Integral Membrane Protein; Laboratories; Lead; Learning; Leucine; Libraries; Lipids; Lysosomes; Malignant Neoplasms; Malignant neoplasm of pancreas; Mammalian Cell; Mediating; Medicine; Membrane Proteins; Membrane Transport Proteins; Mentors; Metabolic; Molecular; Molecular Conformation; Molecular Machines; Motivation; Mutation; Normal Cell; Nutrient; Oncogenic; Outcome; Pathway interactions; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phase; Phosphotransferases; Positioning Attribute; Process; Proteins; Protocols documentation; Recording of previous events; Research; Research Personnel; Role; Scientist; Signal Transduction; Starvation; Structure; Testing; Training; Transport Process; Validation; Work; X-Ray Crystallography; analog; base; cancer cell; cancer type; career; chemotherapy; diagnostic tool; drug development; drug discovery; effective therapy; expectation; experimental study; extracellular; fighting; improved; innovation; insight; lysosomal proteins; mTOR protein; metabolomics; mutant; nanobodies; nanodisk; novel; novel therapeutics; pancreatic cancer cells; prevent; programs; proteoliposomes; rational design; reconstitution; screening; small molecule; small molecule inhibitor; small molecule libraries; structural biology; success; therapeutic target; tumor; tumor metabolism; tumor microenvironment

ABSTRACT Many RAS-transformed aggressive cancer cells are able to escape cytotoxic chemotherapy and survive in near-starvation conditions. One adaptation making them hard to kill is their ability to scavenge extracellular proteins and recycle the cellular components using autophagy, both of which are then digested in lysosomes to recover free amino acids. The process of scavenging and internalization is known as macropinocytosis, and cancer cells aquire mutations to upregulate it when faced with nutrient-poor conditions. To fight such cancers, researchers are currently targeting the macropinocytosis machinery; however, because this process is not very well studied, and likely involves hundreds of proteins with redundant functions, such therapy might prove challenging to exectute without involving multiple drugs. We propose a better way of targeting nutrient-scavenging cancers by focusing on a downstream process of releasing digested nutrients from lysosomes to cytosol. The Sabatini Lab showed that the release of digested amino acids from lysosomes is orchestrated by the mTORC1 pathway, and specifically by SLC38A9. This lysosomal membrane protein senses the rising levels of digested amino acids in lysosomes by directly binding arginine. Our lab found that this sensing is coupled to activation of the transporter function, and results in the efflux of essential non-polar amino-acids, such as leucine, from lysosomes to cytosol. Importantly, RAS-transformed pancreatic cancer cells that feed on extracellular protein were unable to efficiently form tumors in the absence of SLC38A9. These results present a novel therapeutic idea of targeting a metabolic vulnerability in cancers transformed by oncogenic RAS signaling. In this five-year project we will elucidate the molecular mechanism of releasing digested amino acids from lysosomes to cytosol via SLC38A9, and therefore provide a rational approach to drug discovery. In parallel to that, we will screen for small molecules that specifically bind to SLC38A9, and develop them into chemical probes that modulate its transport activity. Impaired efflux function of SLC38A9 will lead to entrapment of macropinocytosis-derived amino-acids within the lysosomes, and our expectation is that this treatment will impair the growth of RAS-mutant and other tumors addicted to protein scavenging, while sparing normal cells that lack this requirement. Over the first two years of the mentored phase, I will be based at the Whitehead Institute, where I will learn cell signaling and metabolomics approaches from the experts in the field. I will also venture into a completely new research area to me, chemical biology, working with experts at the Broad Institute. After the completion of my K99 training, my aspiration is to lead a laboratory that combines cell signaling, structural biology, and chemical biology to study membrane transporters and their role in cancer metabolism. In parallel to understanding basic biology, I want my lab to develop specific small-molecule modulators that adjust transport activities of those proteins, facilitating further research in the field, and in long term – new medicines.

抽象的 许多 RAS 转化的侵袭性癌细胞能够逃避细胞毒性化疗并在 近乎饥饿的状况。使它们难以被杀死的一种适应是它们清除细胞外物质的能力 蛋白质并利用自噬回收细胞成分，然后两者都在溶酶体中被消化 回收游离氨基酸。清除和内化的过程称为巨胞饮作用，并且 当面临营养不良的情况时，癌细胞会发生突变以上调它。为了对抗此类癌症， 研究人员目前正在针对巨胞饮机制；然而，由于这个过程不是很 经过充分研究，并且可能涉及数百种具有冗余功能的蛋白质，这种疗法可能会证明 在不涉及多种药物的情况下执行起来具有挑战性。我们提出了一种更好的定位方法 通过关注释放消化的营养物质的下游过程来治疗营养清除癌症 溶酶体到细胞质。 Sabatini 实验室表明，溶酶体中消化的氨基酸的释放是 由 mTORC1 通路，特别是 SLC38A9 精心策划。这种溶酶体膜蛋白 通过直接结合精氨酸来感知溶酶体中消化氨基酸水平的上升。我们的实验室发现 这种传感与转运蛋白功能的激活相结合，并导致必需的非极性物质的流出 氨基酸，例如亮氨酸，从溶酶体到细胞质。重要的是，RAS 转化的胰腺癌 在缺乏 SLC38A9 的情况下，以细胞外蛋白为食的细胞无法有效形成肿瘤。 这些结果提出了一种新的治疗思路，即针对癌症中的代谢脆弱性， 致癌 RAS 信号传导。在这个为期五年的项目中，我们将阐明释放的分子机制 通过 SLC38A9 将氨基酸从溶酶体消化到细胞质中，因此提供了一种合理的方法 药物发现。与此同时，我们将筛选与 SLC38A9 特异性结合的小分子，并且 将它们开发成调节其运输活动的化学探针。 SLC38A9 的外排功能受损将 导致巨胞饮作用衍生的氨基酸被困在溶酶体内，我们的期望是 这种治疗将损害 RAS 突变体和其他依赖蛋白质清除的肿瘤的生长，同时 保留缺乏这种要求的正常细胞。在指导阶段的前两年，我将基于 在怀特海德研究所，我将向以下领域的专家学习细胞信号传导和代谢组学方法 领域。我还将冒险进入一个对我来说全新的研究领域，化学生物学，与专家合作 在布罗德研究所。完成 K99 培训后，我的愿望是领导一个实验室 结合细胞信号传导、结构生物学和化学生物学来研究膜转运蛋白及其作用 在癌症代谢中。在了解基础生物学的同时，我希望我的实验室能够开发特定的 小分子调节剂可以调节这些蛋白质的转运活性，促进进一步的研究 领域，从长远来看——新药。