ISOPRENIOD SYNTHESIS & TUMOR CELL GROWTH

该项目的长期目标是研究 异戊二烯生物合成与细胞增殖的关系，以及 肿瘤化疗新方法的研究进展 抑制类异戊二烯途径中的调节酶， 3羟基3甲基戊二酰辅酶A(HMG-CoA)还原酶。 这种酶催化甲氧丙酮酸的形成，甲氧戊酸是一种重要的 甾醇和其他异戊二烯类化合物的前体， Dolicol和新发现的类异戊二烯蛋白。活动 HMGCoA还原酶在许多类型的肿瘤中升高，并且 来自前一个项目期的数据显示，一种 这种酶，梅维诺林，抑制皮下血管的生长。 小鼠神经母细胞瘤。梅维诺林的持续评价 下一个项目期将确定该化合物是否可以 抑制大鼠脑瘤模型的肿瘤生长 脑内C-6胶质瘤和脑池内Walker 256 癌症。将使用几个标准来评估 梅维诺林，包括存活曲线和克隆形成试验 残留的肿瘤。正常大脑的组织学研究，以及 骨髓细胞的克隆形成分析将确定潜在的 梅维诺林的毒副作用。这些研究的结果将 指示甲维诺林的临床试验阶段是否 这是正当的。培养的神经母细胞瘤和LM细胞将用于 确定甲氧戊酸合成受阻原因的基础研究 导致细胞周期停止。这些研究将集中于 特别是一类新的蛋白质，这些蛋白质经过后修饰。 平移地与衍生于 甲氧戊酸。其中一种蛋白质，定位于 核，将通过等电聚焦和SDS凝胶进行提纯 电泳法，单抗将由 标准小鼠杂交瘤技术。然后抗体将被 用于确定(1)高分子量原子核是否 类异戊二烯蛋白在抗原性上与低分子 在其他亚细胞中发现的重量较大的异戊二烯蛋白 隔室，(2)甲氧丙戊酸的合成是否受到抑制 梅维诺林导致多肽合成减少 部分类异戊二烯蛋白，(3)是否合成 核类异戊二烯蛋白发生在细胞周期的特定阶段 细胞周期，以及(4)核类异戊二烯蛋白是否表现出 一种DNA结合蛋白的性质。这些研究将提供 甲伐他汀类药物作用机制的新认识 对细胞生长的要求。

The long-term objectives of the project are the study of isoprenoid biosynthesis in relation to cell proliferation, and the development of new approaches to cancer chemotherapy based on inhibition of the regulatory enzyme in the isoprenoid pathway, 3hydroxy3methylglutaryl coenzyme A (HMG-CoA) reductase. This enzyme catalyzes the formation of mevalonate, an essential precursor of sterols and other isoprenoids such as ubiquinone, dolichol, and newly discovered isoprenoid proteins. The activity of HMGCoA reductase is elevated in many types of tumors, and data from the preceding project period showed that an inhibitor of this enzyme, mevinolin, suppresses the growth of subcutaneous neuroblastoma in mice. Continued evaluation of mevinolin during the next project period will establish whether this compound can suppress tumor growth in rat brain tumor models such as intracerebral C-6 glioma and intracisternal Walker 256 carcinoma. Several criteria will be used to assess the efficacy of mevinolin, including survival curves and clonogenic assays of residual tumors. Histological studies of normal brain, and colonyforming assays of bone marrow cells will identify potential toxic side effects of mevinolin. The results of these studies will indicate whether phaseI clinical trials of mevinolin are warranted. Cultured neuroblastoma and LM cells will be used in basic studies to determine why blocking mevalonate synthesis leads to arrest of cell cycling. These studies will focus specifically on a novel class of proteins which are modified post- translationally with isoprenoid prosthetic groups derived from mevalonate. One of these proteins, which is localized in the nucleus, will be purified by isoelectric focusing and SDSgel electrophoresis, and a monoclonal antibody will be raised by standard mouse hybridoma technology. The antibody will then be used to determine (1) whether the highmolecular weight nuclear isoprenoid protein is related antigenically to the lowermolecular weight isoprenoid proteins found in other subcellular compartments, (2) whether suppression of mevalonate synthesis by mevinolin results in a decreased synthesis of the polypeptide portion of the isoprenoid protein,, (3) whether the synthesis of the nuclear isoprenoid protein occurs during a specific phase of the cell cycle, and (4) whether the nuclear isoprenoid protein exhibits properties of a DNAbinding protein. These studies will provide new insight into the mechanism underlying the mevalonate requirement for cell growth.