CLINICAL PHENOTYPE TARGETED ANTIFOLATE CHEMOTHERAPY

临床表型靶向抗叶酸化疗

• 批准号: 2654243
• 负责人: JULIO C BARREDO
• 金额: $ 10万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2654243
• 关键词: CD34 molecule; DNA methylation; acute leukemia; acute lymphocytic leukemia; acute nonlymphocytic leukemia; clinical research; colony stimulating factor; cytotoxicity; drug metabolism; drug resistance; enzyme activity; folate antagonist; gene expression; hematopoietic stem cells; human subject; human therapy evaluation; messenger RNA; methotrexate; neoplasm /cancer chemotherapy; neoplasm /cancer pharmacology; outcomes research; phenotype; tetrahydrofolylpolyglutamate synthase; tissue /cell culture; transfection /expression vector

The drug sensitivity and clinical outcome of human leukemias is highly dependent on their cell lineage of origin. This proposal will aim to define biochemical phenotypes with respect to drug metabolism that account for the lineage-specific response to antifolates exhibited by human leukemias. Polyglutamylation of classical and novel antifolates by the enzyme Folylpolyglutamate synthetase (FPGS) is essential to their pharmacological activity, resulting in prolonged intracellular retention and increased cytotoxicity. The proposed studies will test the hypothesis that the response of human leukemias to antifolates depend upon the expression of FPGS. We will investigate the biochemical and molecular basis for the reported clinical observation that a lineage- specific increase in FPGS activity occurs after in vivo leukemic blasts' exposure to these drugs. These studies will define the role of substrate affinity for FPGS and inhibition of key folate-metabolizing enzymes, and the effects of non-polyglutamylatable antifolates and natural folates. Similar studies with normal hematopoietic progenitors after exposure to antifolates will define the potential role of FPGS in drug selectivity. Further, changes in DNA methylation and FPGS mRNA expression in normal bone marrow cells and leukemic blasts will be investigated. To evaluate the clinical significance of these results, FPGS and polyglutamylation related parameters will be determined in clinical samples from antifolate sensitive and resistant leukemias. The clinical relevance of FPGS in antifolate response will also be tested by growth factor-induced upregulation of FPGS in resistant myeloid leukemic blasts' exposed to these agents, and after transfection of an inducible expression system encoding hFPGS to an "enzyme deficient" resistant leukemic phenotype. Overall, this proposal should provide a definitive answer to: 1. How important is FPGS in the clinical response to antifolates? 2. What are the effects of novel antifolates on leukemic blasts' FPGS expression, and do these differ in sensitive vs resistant phenotypes vs normal bone marrow progenitors? 3. Is the lineage-specific expression of FPGS an important clinical determinant of a biochemical phenotype predictor of antifolate tumor response?

人类白血病的药物敏感性和临床结果高度 取决于其细胞谱系的起源。该提案旨在 定义与药物代谢相关的生化表型 解释了抗叶酸剂表现出的谱系特异性反应 人类白血病。经典和新型抗叶酸剂的多谷氨酰化 叶酰聚谷氨酸合成酶 (FPGS) 对于它们的生长至关重要 药理活性，导致细胞内滞留时间延长 并增加细胞毒性。 拟议的研究将测试 假设人类白血病对抗叶酸药物的反应取决于 FPGS 的表达。我们将调查生化和 所报告的临床观察的分子基础是谱系- 体内白血病原始细胞后 FPGS 活性发生特异性增加 接触这些药物。这些研究将定义底物的作用 对 FPGS 的亲和力和对关键叶酸代谢酶的抑制，以及 非聚谷氨酰化抗叶酸剂和天然叶酸的作用。 对正常造血祖细胞暴露后进行的类似研究 抗叶酸剂将定义 FPGS 在药物选择性中的潜在作用。 此外，正常人体内 DNA 甲基化和 FPGS mRNA 表达的变化 将研究骨髓细胞和白血病细胞。评估 这些结果、FPGS 和聚谷氨酰化的临床意义 相关参数将在抗叶酸剂的临床样品中测定 敏感和耐药白血病。 FPGS 的临床意义 抗叶酸反应也将通过生长因子诱导进行测试 暴露于耐药性髓系白血病母细胞中 FPGS 的上调 这些试剂，以及转染诱导表达系统后 将 hFPGS 编码为“酶缺乏”的抗性白血病表型。 总体而言，该提案应该对以下问题提供明确的答案： 1. 如何 FPGS 在抗叶酸药物的临床反应中重要吗？ 2. 什么是 新型抗叶酸剂对白血病细胞 FPGS 表达的影响，以及 这些在敏感表型、耐药表型与正常骨方面有何不同 骨髓祖细胞？ 3. FPGS 的谱系特异性表达是 生化表型预测因子的重要临床决定因素 抗叶酸治疗肿瘤反应？