CLINICAL PHENOTYPE TARGETED ANTIFOLATE CHEMOTHERAPY

临床表型靶向抗叶酸化疗

• 批准号: 2871914
• 负责人: JULIO C BARREDO
• 金额: $ 10.08万
• 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/2871914
• 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 取决于他们的原始细胞谱系。该提议将旨在 在药物代谢方面定义生化表型 解释对谱系对抗染料的特异性反应 人类白血病。经典和新颖的抗粉末的聚谷氨酰化 酶Folylypolyglutamate合成酶（FPGS）对于它们的 药理学活性，导致细胞内保留延长 并增加了细胞毒性。 拟议的研究将测试 假设人白血病对抗染料的反应取决于 在表达FPG时。我们将研究生化和 据报道的临床观察的分子基础 FPGS活性的特异性增加发生在体内白血病爆炸之后 暴露于这些药物。这些研究将定义底物的作用 对FPG的亲和力和抑制关键的叶酸代谢酶，以及 非丙二酰氨基甲基酸盐和天然叶状物的作用。 暴露后，对正常造血祖细胞的类似研究 抗染料将定义FPG在药物选择性中的潜在作用。 此外，正常的DNA甲基化和FPGS mRNA表达的变化 将研究骨髓细胞和白血病爆炸。评估 这些结果的临床意义，FPG和聚谷氨酸化 相关参数将在抗叶酸的临床样品中确定 敏感和抗性白血病。 FPG在 抗叶酸反应也将通过生长因子诱导的 FPG在耐药性髓样白血病爆炸中的上调 这些药物，以及转染诱导表达系统后 将HFPG编码为“酶不足”的抗性白血病表型。 总体而言，该提案应提供一个确定的答案：1。 重要的是FPG在临床对抗染料的临床反应中是否重要？ 2。是 新型抗树脂对白血病爆炸的FPG表达和 这些在敏感与抗性表型与正常骨骼上有不同吗 骨髓祖细胞？ 3。是FPGS的谱系特异性表达 生化表型预测因子的重要临床决定因素 抗叶酸肿瘤反应？