ROLE OF DUTPASE EXPRESSION IN CANCER CHEMOTHERAPY

DuTPase 表达在癌症化疗中的作用

• 批准号: 6489326
• 负责人: ROBERT D LADNER
• 金额: $ 26.53万
• 依托单位: UNIV OF MED/DENT NJ-SCH OSTEOPATHIC MED
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-09 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6489326
• 关键词: acid anhydride hydrolase; cell line; clinical research; colon neoplasms; combination chemotherapy; enzyme activity; enzyme induction /repression; floxuridine; fluorouracil; human subject; human therapy evaluation; isozymes; leucovorin; metastasis; mitochondria; neoplasm /cancer chemotherapy; uridine triphosphate; western blottings

For more than forty years, thymidylate metabolism has been an important biochemical target for widely utilized anti-cancer agents. Inhibitors of this pathway such as the fluoropyrimidines and antifolates induce a severe depletion of TTP pools resulting in nucleotide pool imbalance and cell killing through a process termed "thymineless death." Investigation of the underlying mechanisms of this process suggest that aberrant uracil-DNA metabolism may be an important mediator of DNA damage and cell killing. The broad, long-term objectives of this proposal are: 1) to elucidate the role of aberrant dUTP metabolism as a molecular mechanism of cell killing induced by chemotherapeutic agents that target thymidylate biosynthesis and; 2) to better understand the role of key enzymes involved in dUTP metabolism in modulating chemosensitivity. In this study, the applicants propose a mechanistic analysis of thymineless death using human colon cancer cell lines that over express the enzyme deoxyuridine triphosphate nucleotide hydrolase (dUTPase). dUTPase catalyzes the hydrolysis of dUTP to form dUMP and PPi, thereby eliminating dUTP from the DNA biosynthetic pathway. The applicants hypothesize that dUTPase over-expression counters the cytotoxic effect of FUdR treatment by limiting the expansion of dUTP pools. Although there is significant evidence suggesting that uracil-DNA metabolism may be a critical factor in mediating cytotoxicity, there have been no biochemical studies performed to clarify the role of human dUTPase isoform expression in modulating chemosensitivity. The proposed studies are designed to correlate key mechanistic hallmarks of uracil-DNA mediated cytotoxicity with cell death induced by fluorodeoxyuridine. Specific Aim 1 investigates the role of dUTPase isoform over-expression as a mechanism of resistance to FUdR-induced cytotoxicity. Specific Aim 2 investigates the correlation between biochemical endpoints of aberrant uracil-DNA metabolism and chemosensitivity to FUdR. Specific Aim 3 investigates the significance of dUTPase isoform expression in predicting patient response to fluoropyrimidine-based chemotherapy and overall survival in metastatic colon cancer. A better understanding of the role of aberrant uracil-DNA metabolism in mediating thymineless death should not only enhance our knowledge of the molecular mechanism of drug action of these important chemotherapeutics, but also provide insight into novel and improved treatment strategies.

四十多年来，胸苷酸代谢一直是 广泛使用的抗癌药物的重要生化靶点。抑制剂 该途径的影响，例如氟嘧啶和抗叶酸药物会导致严重的 TTP 池耗尽导致核苷酸池失衡和细胞死亡 通过一个被称为“无胸腺死亡”的过程。底层调查 这一过程的机制表明异常的尿嘧啶-DNA 代谢可能是 DNA损伤和细胞杀伤的重要介质。广泛、长期 该提案的目标是：1) 阐明异常 dUTP 的作用 代谢作为化疗诱导细胞杀伤的分子机制 靶向胸苷酸生物合成的药物； 2）更好地理解 参与 dUTP 代谢的关键酶在调节化学敏感性中的作用。 在这项研究中，申请人提出了胸腺嘧啶的机制分析 使用过度表达该酶的人类结肠癌细胞系导致死亡 脱氧尿苷三磷酸核苷酸水解酶（dUTPase）。 dUTPase 催化 dUTP 水解形成 dUMP 和 PPi，从而从 DNA 中消除 dUTP 生物合成途径。申请人假设 dUTPase 过度表达 通过限制 FUdR 的扩增来对抗 FUdR 治疗的细胞毒性作用 dUTP 池。尽管有大量证据表明尿嘧啶-DNA 代谢可能是介导细胞毒性的关键因素， 没有进行生化研究来阐明人 dUTPase 亚型的作用 调节化学敏感性的表达。拟议的研究旨在 将尿嘧啶-DNA介导的细胞毒性的关键机制特征与 氟脱氧尿苷诱导的细胞死亡。具体目标 1 研究角色 dUTPase 亚型过表达作为 FUdR 诱导抗性机制的研究 细胞毒性。具体目标 2 研究生化指标之间的相关性 异常尿嘧啶-DNA 代谢和 FUdR 化学敏感性的终点。 具体目标 3 研究 dUTPase 亚型表达在 预测患者对基于氟嘧啶的化疗的反应和总体反应 转移性结肠癌的生存率。更好地理解角色的作用 异常的尿嘧啶-DNA 代谢在介导无胸腺嘧啶死亡中不仅应该 增强我们对这些药物作用分子机制的了解 重要的化疗药物，同时也提供了对新颖和改进的见解 治疗策略。