The role of NAGK cysteine deprotonation in nutrient stress and cancer progression

NAGK 半胱氨酸去质子化在营养应激和癌症进展中的作用

• 批准号: 10652823
• 负责人: JOHN BLENIS
• 金额: $ 8.48万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-21 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10652823
• 关键词: Attention; Binding; Cell Communication; Cells; Cysteine; Data; Detection; Development; Disease Progression; Ensure; Environment; Environmental Risk Factor; Event; Frequencies; Global Change; Glutamine; Growth; Hexosamines; Immune Evasion; Iodoacetamide; Knock-out; Label; Malignant Neoplasms; Mediating; Metabolic; Modification; N-Acetylglucosamine kinase; Neoplasm Metastasis; Nucleotides; Nutrient; Nutrient Depletion; Oxidants; Pathway interactions; Perfusion; Phosphorylation; Phosphotransferases; Polysaccharides; Predisposition; Process; Property; Proteins; Proteome; Reaction; Recycling; Regulation; Research; Resources; Role; Signal Transduction; Site; Stimulus; Stress; Sulfhydryl Compounds; Therapeutic; Therapeutic Intervention; Tissues; Tumor Promotion; Work; biological adaptation to stress; cancer cell; cost; deprivation; deprotonation; extracellular; glycosylation; glycosyltransferase; neoplastic cell; novel; oxidation; programs; protonation; resilience; response; small molecule; sugar; sugar nucleotide; therapeutic target; tumor; tumor growth; tumor microenvironment; tumor progression; uptake

PROJECT SUMMARY/ ABSTRACT Changes in cellular glycosylation support cancer growth and progression, but the biosynthetic pathways that supply the required nucleotide-sugar precursors are resource intensive. The cell therefore utilizes salvage pathways to recycle free sugars following glycan degradation or extracellular uptake, offsetting the need for their de novo synthesis. Little is known about the extent to which cancer cells rely on sugar salvage pathways or how these pathways are regulated. Recently, the salvage kinase responsible for phosphorylating N- acetylglucosamine (GlcNAc) for reuse by the hexosamine biosynthetic pathway, N-acetyl-D-glucosamine kinase (NAGK), was found to support tumor growth, providing early evidence that cancer cells may indeed rely heavily on salvage. Preliminary data presented here show that NAGK is deprotonated at two cysteines in response to nutrient limitation, a condition frequently encountered in the tumor microenvironment. Cysteine deprotonation can alter protein activity and promote subsequent oxidation. This deprotonation is observed not just on NAGK, but on proteins throughout the cell in what may be a previously unrecognized adaptation to stress. Cysteines, especially in the deprotonated thiolate state, serves as ready sites of covalent inhibition by small molecule electrophiles. Thus, the wide-spread increase in thiolates in response to nutrient limitation may represent a class of proteins that are more responsive to covalent inhibition within stressed tumor cells than when in their protonated thiol state in healthy, perfused tissue. The aims detailed in this proposal will first characterize the effect of cysteine deprotonation on NAGK activity and its role in tumor growth and will then focus on identifying the global changes in cysteine protonation status in response to nutrient limitation as well as the environmental factors that promote this deprotonation. This work will characterize, both mechanistically and broadly, a novel stress response that may promote tumor progression despite nutrient limitation but that may also render the tumor more vulnerable to therapeutic intervention with small molecule electrophiles.

项目概要/摘要 细胞糖基化的变化支持癌症的生长和进展，但生物合成途径 供应所需的核苷酸糖前体是资源密集型的。因此，细胞利用回收 聚糖降解或细胞外摄取后回收游离糖的途径，抵消了对其的需求 从头合成。人们对癌细胞依赖糖回收途径的程度以及如何依赖糖回收途径知之甚少。 这些途径受到监管。最近，负责磷酸化 N-的挽救激酶 乙酰氨基葡萄糖 (GlcNAc)，用于己糖胺生物合成途径、N-乙酰基-D-氨基葡萄糖激酶的再利用 （NAGK），被发现支持肿瘤生长，提供了早期证据表明癌细胞确实可能严重依赖 关于打捞。这里提供的初步数据表明，NAGK 在两个半胱氨酸处被去质子化，以响应 营养限制，肿瘤微环境中经常遇到的情况。半胱氨酸去质子化 可以改变蛋白质活性并促进随后的氧化。这种去质子化不仅在 NAGK 上观察到， 但在整个细胞的蛋白质上，这可能是一种以前未被认识到的对压力的适应。半胱氨酸， 特别是在去质子化硫醇盐状态下，可作为小分子共价抑制的现成位点 亲电子试剂。因此，硫醇盐因营养限制而广泛增加可能代表了一类 与在肿瘤细胞中相比，这些蛋白质对应激肿瘤细胞内的共价抑制更敏感 健康灌注组织中的质子化硫醇状态。本提案中详述的目标首先将描述 半胱氨酸去质子化对 NAGK 活性的影响及其在肿瘤生长中的作用，然后将重点鉴定 半胱氨酸质子化状态的全球变化响应营养限制以及环境 促进这种去质子化的因素。这部作品将从机制上和广义上描述一部小说 尽管营养有限，应激反应仍可能促进肿瘤进展，但也可能导致 肿瘤更容易受到小分子亲电体的治疗干预。