Molecular Regulation of Folate and Antifolate Transport

叶酸和抗叶酸转运的分子调节

• 批准号: 10163805
• 负责人: Zhanjun Hou
• 金额: $ 29.26万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-02-12 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10163805
• 关键词: Abbreviations; Acids; Alimta; Anabolism; Anatomy; Anions; Antineoplastic Agents; Biological; Biology; Cancer Etiology; Carbon; Cell Survival; Cell membrane; Cells; Clinical; Complex; Coupled; Cytosol; DHFR gene; Diffusion; Disease; Drug resistance; Epithelial; FRAP1 gene; Folic Acid; Folic Acid Antagonists; Generations; Genetic Transcription; Glutathione; Glycine; Glycine Hydroxymethyltransferase; Goals; Grant; Human; Human Biology; Hydroxymethyltransferases; Hypoxia; Immunohistochemistry; Lead; Leukemic Cell; Lung; Malabsorption Syndromes; Malignant Neoplasms; Malignant Pleural Mesothelioma; Mammalian Cell; Mediating; Membrane; Membrane Transport Proteins; Metabolic Pathway; Metabolism; Methionine; Methotrexate; Mitochondria; Molecular; Mutation; Normal Cell; Orphan Drugs; Ovarian; Pancreas; Pancreatic Adenocarcinoma; Pathway interactions; Patients; Pemetrexed; Pharmacodynamics; Physiological; Physiology; Plasma; Protons; Publishing; Purine Nucleotides; Purines; Raltitrexed; Reaction; Reactive Oxygen Species; Regulation; Reporting; Research; Resistance; Ribonucleotides; Role; SLC19A1 gene; Series; Serine; Signal Transduction; Specimen; Structure-Activity Relationship; System; Tetrahydrofolates; Text; Therapeutic; Time; Tissues; Tumor Cell Line; Upper digestive tract structure; absorption; antitumor agent; antitumor drug; clinical translation; cofactor; cytotoxic; design; differential expression; folate-binding protein; glycine amide; hereditary folate malabsorption; human disease; hydrophilicity; in vivo; inhibitor/antagonist; neoplastic cell; novel; novel strategies; novel therapeutics; protein protein interaction; targeted agent; targeted treatment; thymidylate; tumor; tumor microenvironment; tumor progression; uptake

ABSTRACT Folates are anionic molecules that cross biological membranes poorly by diffusion. Folate uptake is principally mediated by the reduced folate carrier (RFC; SLC19A1) and the proton-coupled folate transporter (PCFT; SLC46A1). Upon internalization, folates facilitate one-carbon (C1) metabolism, leading to synthesis of glycine, serine and methionine, and purine nucleotides and thymidylate. C1 metabolism encompasses cytosolic and mitochondrial pathways connected by an interchange between serine, glycine and formate. The ubiquitously expressed RFC is the major membrane transporter for folates in cells and tissues. RFC is also an important transporter of clinically used C1 inhibitors (e.g., pemetrexed) for cancer, as well as other indications, and loss of RFC is associated with drug resistance. PCFT mediates folate absorption in the upper gastrointestinal tract. PCFT levels in other tissues are generally modest. Unlike RFC, PCFT transport is optimal at acidic pH, approximating the tumor microenvironment. PCFT is widely expressed in human tumor cell lines and primary specimens. We discovered novel cytotoxic PCFT-targeted C1 inhibitors for cancer and established a comprehensive structure-activity relationship for PCFT that is distinct from RFC. Novel pyrrolopyrimidine compounds (AGF94 & AGF347) showed potent anti-proliferative activities toward PCFT-expressing tumors that were augmented at acid pH. Following internalization, AGF94 inhibited de novo purine (DNP) biosyn- thesis at β-glycinamide ribonucleotide formyltransferase (GARFTase), whereas AGF347 inhibited mito- chondrial C1 metabolism at serine hydroxymethyltransferase 2 (SHMT2), with additional effects on C1 metabolism in the cytosol (DNP biosynthesis at GARFTase and 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase, and at SHMT1). Both inhibitors depleted ATP; AGF347 depleted glycine and cytosolic C1 pools, with downstream effects on glutathione and levels of reactive oxygen species, and on mTOR signaling. AGF94 and AGF347 showed promising in vivo efficacies toward early and upstage tumor xeno- grafts. We posit that our PCFT-targeted agents offer an entirely new approach for treating cancer. In this R01 renewal, we explore the unique biology of the facilitative folate transporters and C1 metabolism, with a goal of further optimizing therapeutic applications of our novel agents. We propose in Aim 1 to characterize the cellular pharmacodynamics and molecular regulation of PCFT in relation to PCFT-targeted therapies, including transcriptional mechanisms and the role of protein-protein interactions in regulating PCFT. In Aim 2, we will characterize the cellular pharmacodynamics of mitochondrial C1 inhibitors including their transport and metabolism. An important focus of both Aims 1 and 2 will be on the role of the tumor microenvironment, including the impact of hypoxia and acid pH on anti-tumor drug biology and efficacy of these series. Our proposed studies are distinctive for their novelty and focus on clinical translation.

抽象的 叶酸是阴离子分子，通过扩散很难穿过生物膜。叶酸的摄取主要是 由还原型叶酸载体（RFC；SLC19A1）和质子耦合叶酸转运蛋白（PCFT；SLC19A1）介导 SLC46A1）。内化后，叶酸促进一碳 (C1) 代谢，导致甘氨酸的合成， 丝氨酸和甲硫氨酸，以及嘌呤核苷酸和胸苷酸。 C1代谢包括细胞质和 线粒体途径通过丝氨酸、甘氨酸和甲酸之间的交换而连接。无处不在的 表达的 RFC 是细胞和组织中叶酸的主要膜转运蛋白。 RFC也是一个重要的 临床上用于治疗癌症以及其他适应症的 C1 抑制剂（例如培美曲塞）的转运蛋白，以及丧失 RFC与耐药性相关。 PCFT 介导上消化道的叶酸吸收。 其他组织中的 PCFT 水平通常较低。与 RFC 不同，PCFT 运输在酸性 pH 条件下最佳， 近似肿瘤微环境。 PCFT广泛表达于人类肿瘤细胞系和原代细胞中 标本。我们发现了新型细胞毒性 PCFT 靶向 C1 癌症抑制剂，并建立了 PCFT 的全面构效关系与 RFC 不同。新型吡咯并嘧啶 化合物（AGF94 和 AGF347）对表达 PCFT 的肿瘤表现出有效的抗增殖活性 在酸性 pH 值下增强。内化后，AGF94 抑制从头嘌呤 (DNP) 生物合成 论文研究β-甘氨酰胺核糖核苷酸甲酰基转移酶（GARFTase），而 AGF347 抑制线粒体 丝氨酸羟甲基转移酶 2 (SHMT2) 的软骨 C1 代谢，对 C1 具有额外影响 细胞质中的代谢（GARFTase 上的 DNP 生物合成和 5-氨基咪唑-4-甲酰胺 核糖核苷酸甲酰基转移酶和 SHMT1）。两种抑制剂都会耗尽 ATP； AGF347 耗尽甘氨酸和 胞质 C1 池，对谷胱甘肽和活性氧水平以及 mTOR 具有下游影响 发信号。 AGF94 和 AGF347 对早期和晚期肿瘤异种表现出有希望的体内功效 移植物。我们认为，我们的 PCFT 靶向药物提供了一种全新的癌症治疗方法。在这个R01 更新，我们探索促进叶酸转运蛋白和 C1 代谢的独特生物学，目标 进一步优化我们的新药物的治疗应用。我们在目标 1 中建议描述 PCFT 的细胞药效学和分子调控与 PCFT 靶向治疗相关，包括 转录机制以及蛋白质-蛋白质相互作用在调节 PCFT 中的作用。在目标 2 中，我们将 表征线粒体 C1 抑制剂的细胞药效学，包括其转运和 代谢。目标 1 和 2 的一个重要焦点是肿瘤微环境的作用， 包括缺氧和酸性pH值对这些系列抗肿瘤药物生物学和功效的影响。我们的 拟议的研究因其新颖性和侧重于临床转化而与众不同。