THYMIDYLATE SYNTHASE FLUORODEOXYURIDINE RESISTANCE

胸苷酸合成酶氟脱氧尿苷抗性

• 批准号: 2091340
• 负责人: FRANKLIN G. BERGER
• 金额: $ 11.72万
• 依托单位: UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-03-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2091340
• 关键词: aminoacid; antineoplastics; athymic mouse; carcinoma; cell bank /registry; chemical substitution; clone cells; colon neoplasms; complementary DNA; drug resistance; enzyme mechanism; enzyme structure; floxuridine; gene expression; human population genetics; human tissue; ligands; microorganism genetics; neoplasm /cancer genetics; neoplasm /cancer pharmacology; pharmacogenetics; prognosis; protein sequence; restriction fragment length polymorphism; thymidylate synthase; transfection

Clinical resistance to chemotherapeutic drugs is a major impediment to the successful treatment of human neoplasia. though a great deal of research on model cell lines and tumors has allowed an understanding of the determinants of response and the mechanisms of resistance to a variety of useful drugs, there is need to expand existing information and to assess its significance in the clinical setting. Thus, it is pertinent to examine the extent and impact of genetic variation on parameters of drug response in human tumor cells of relevant histological origin. The fluoropyrimidine anti-metabolite 5-fluoro-2'-deoxyuridine (FdUrd) inhibits cell growth through the formation of 5-fluoro-2'- deoxyurdylic acid (FdUMP), which binds to and inhibits thymidylate synthase (TS). In previous work, we have shown that response to FdUrd varies considerably among human colonic tumor cell lines. Of particular interest is cell line HCT116, which produces a variant form of TS exhibiting a reduced affinity for FdUMP; this alteration results from a T -> C mutation in the TS gene, which causes the replacement of a tyrosine by a histidine at residue 33 of the TS polypeptide. The Tyr33 - > His33 change confers relative resistance to the inhibitory effects of FdUrd in both mammalian and bacterial cells. In the present application, we propose to conduct further studies of this mutation and its role in response to FdUrd in colonic tumor cells. We will: (1) determine the origin and frequency of the Tyr33 -> His33 substitution among colon tumor cell lines; (2) compare the Tyr33 and His33 forms of human TS with regard to their kinetics of interactions with ligands; (3) characterize the effects of different amino acid substitutions at residue 33; (4) identify and study additional variations in TS structure and function among a variety of human colonic tumor cell lines. These experiments will provide information on the mechanism by which the Tyr33 -> His33 mutation perturbs the function of TS as a fluoropyrimidine target. In all, the study of TS and its function as a drug target will generate fundamental knowledge on the relationship between protein structure and function, promoting the development of improved strategies for the design and utilization of anti-neoplastic agents. Furthermore, these studies will result in a deeper understanding of the genetic factors that govern drug response, and may lead to the identification of markers that could be useful in the pre-clinical prediction of therapeutic response in many patients.

临床对化疗药物的耐药性是化疗的主要障碍 成功治疗人类肿瘤。 虽然有很多 对模型细胞系和肿瘤的研究使我们能够了解 反应的决定因素和耐药机制 各种有用的药物，需要扩大现有的信息和 评估其在临床环境中的意义。 因此，它是 与检查遗传变异的程度和影响有关 相关组织学人类肿瘤细胞的药物反应参数 起源。 氟嘧啶抗代谢物 5-氟-2'-脱氧尿苷 (FdUrd) 通过形成 5-氟-2'- 抑制细胞生长 脱氧尿苷酸 (FdUMP)，结合并抑制胸苷酸 合酶（TS）。 在之前的工作中，我们已经展示了对 FdUrd 的响应 人类结肠肿瘤细胞系之间差异很大。 特别是 人们感兴趣的是细胞系 HCT116，它产生 TS 的变体形式 对 FdUMP 的亲和力降低；这种改变的结果是 TS 基因中的 T -> C 突变，导致替换 TS 多肽残基 33 处的酪氨酸被组氨酸取代。 Tyr33 - > His33 的变化赋予了对以下物质的抑制作用的相对抵抗力 哺乳动物和细菌细胞中的 FdUrd。 在本申请中， 我们建议对该突变及其作用进行进一步研究 结肠肿瘤细胞对 FdUrd 的反应。 我们将： (1) 确定 结肠肿瘤中 Tyr33 -> His33 取代的起源和频率 细胞系； (2) 比较人类 TS 的 Tyr33 和 His33 形式 它们与配体相互作用的动力学； (3) 表征 残基 33 处不同氨基酸取代的影响； (4) 识别 并研究 TS 结构和功能的其他变化 多种人类结肠肿瘤细胞系。 这些实验将 提供有关 Tyr33 -> His33 突变机制的信息 扰乱 TS 作为氟嘧啶靶标的功能。 总而言之， 对 TS 及其作为药物靶点的功能的研究将产生基础 蛋白质结构和功能之间关系的知识， 促进设计和改进改进策略的制定 抗肿瘤药物的利用。 此外，这些研究将 导致对控制药物的遗传因素有更深入的了解 反应，并可能导致标记物的识别，这些标记物可以 可用于许多疾病的治疗反应的临床前预测 患者。