Enhancement of methotrexate uptake in childhood ALL

增强儿童 ALL 的甲氨蝶呤摄取

• 批准号: 7486887
• 负责人: JOHN J MCGUIRE
• 金额: $ 30.55万
• 依托单位: ROSWELL PARK CANCER INSTITUTE CORP
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-29 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7486887
• 关键词: 5' -AMP-activated protein kinase; Acute; Acute leukemia; Address; Adult; Biochemical; Blast Cell; Cardiac; Cell Line; Cells; Chemosensitization; Childhood; Childhood Acute Lymphocytic Leukemia; Childhood Leukemia; Childhood Osteosarcoma; Class; Clinical; Clinical Protocols; Clinical Trials; Cultured Cells; Data; Dihydrofolate Reductase; Disease; Dose; Drug usage; Effectiveness; Enzymes; Goals; Growth; In Vitro; Ischemia; Link; Long-Term Survivors; Lymphoblastic Leukemia; Measures; Mediating; Membrane; Metabolism; Methotrexate; Modeling; Mutation; Myocardial Ischemia; Nucleosides; Numbers; Pathway interactions; Pharmaceutical Preparations; Pharmacology and Toxicology; Post-Translational Protein Processing; Pre-Clinical Model; Protein Biosynthesis; Purines; Radiolabeled; Rate; Research; Resistance; Role; SLC19A1 gene; Schedule; Signal Transduction; Signal Transduction Pathway; System; Testing; Therapeutic; Therapeutic Studies; Treatment Efficacy; Vesicle; acadesine; base; cytotoxic; cytotoxicity; design; imidazole-4-carboxamide; imidazolecarboxamide; in vitro Model; in vivo; inhibitor/antagonist; interest; methotrexate polyglutamate; pre-clinical; preclinical study; purine; radiotracer; reconstitution; translational clinical trial; uptake

DESCRIPTION (provided by applicant): The overall goal of this project is to increase cure of childhood acute lymphoblastic leukemia (ALL) by selectively modulating in leukemic blasts the uptake and metabolism of methotrexate (MTX), a drug key in curing this disease. Our approach is based on our unique finding that exogenous 5-amino-4-imidazole-carboxamide riboside (Z) potentiates uptake, metabolism, and cytotoxic potency of MTX in a preclinical childhood ALL model. Since Z has been used in clinical trials for treating cardiac ischemia, our preclinical studies may be readily translatable into a pediatric clinical trial. Critical to appropriate use of Z as a potentiator is an understanding of its mechanism, which will be elucidated through five Specific Aims: 1) Characterize Z potentiation of MTX uptake and metabolism in a cell culture model of childhood ALL. Our results show that Z potentiates MTX accumulation and metabolism to MTX polyglutamates primarily via a previously undiscovered enhancement in activity of the reduced folate carrier (RFC), which also transports MTX. Z potentiation of MTX uptake by the RFC and the role of other factors in potentiation of MTX polyglutamate accumulation must be fully defined. 2) Determine the role of dihydrofolate reductase (DHFR) inhibition in Z potentiation of MTX uptake. 3) Determine whether specific Z metabolism is required for potentiation of MTX uptake. A requirement for Z transport and metabolism will be explored by using inhibitors of, and/or using cell lines with mutations in, specific nucleoside transport or metabolizing enzymes and by using direct quantitation of potential metabolites of radiolabeled Z. 4) Determine the biochemical mechanisms that transduce the Z signal into increased RFC activity. Since new protein synthesis is not required (Results), Z could increase RFC activity by inducing a post-translational modification or allosterically. Both classes of mechanism will be explored. 5) Define the clinical potential of Z potentiation by determining the dose, schedule, and therapeutic efficacy of MTX+Z combinations in in vivo preclinical models of childhood ALL. If successful, this research could provide a way to increase the effectiveness of methotrexate, a key drug used in treating childhood acute lymphoblastic leukemia, and thus increase the cure rate in this disease.

描述（由申请人提供）：该项目的总体目标是通过选择性调节白血病母细胞对甲氨蝶呤（MTX）的摄取和代谢来提高儿童急性淋巴细胞白血病（ALL）的治愈率，甲氨蝶呤是治疗该病的关键药物。我们的方法是基于我们独特的发现，外源性5-氨基-4-咪唑-羧酰胺核苷(Z)增强MTX在临床前儿童ALL模型中的摄取、代谢和细胞毒性。由于Z已用于治疗心脏缺血的临床试验，我们的临床前研究可能很容易转化为儿科临床试验。正确使用Z作为增强剂的关键是理解其机制，这将通过五个具体目标来阐明：1)在儿童ALL细胞培养模型中表征Z增强MTX摄取和代谢。我们的研究结果表明，Z主要通过先前未发现的减少叶酸载体（RFC）活性的增强来增强MTX的积累和MTX多谷氨酸的代谢，RFC也运输MTX。RFC对MTX摄取的Z增强以及其他因素在MTX聚谷氨酸积累增强中的作用必须充分确定。2)确定二氢叶酸还原酶（DHFR）抑制在MTX摄取Z增强中的作用。3)确定是否需要特定的Z代谢来增强MTX的摄取。通过使用特定核苷转运或代谢酶的抑制剂和/或突变细胞系，以及使用放射性标记Z的潜在代谢物的直接定量，将探索对Z转运和代谢的要求。由于不需要新的蛋白质合成（结果），Z可以通过诱导翻译后修饰或变构来增加RFC活性。我们将探讨这两类机制。5)通过确定MTX+Z组合在儿童ALL临床前模型中的剂量、方案和治疗效果，确定Z增强的临床潜力。如果成功，这项研究将提供一种方法来提高甲氨蝶呤的有效性，从而提高这种疾病的治愈率。甲氨蝶呤是治疗儿童急性淋巴细胞白血病的关键药物。