DISCOVERY OF NATURAL PRODUCTS THAT RESTORE P53 FUNCTION

肿瘤抑制基因p53是最常见的突变基因之一， 基因，是一个非常有吸引力的目标， 新的，基于机制的抗癌剂，可能具有广泛的用途。 据估计，大约一半的人类癌症携带p53突变。 在其他情况下，p53可以通过过度表达而使其功能失活。 蛋白质，如MDM 2。p53可诱导WAF 1/CIP 1的表达， 其通过抑制细胞周期蛋白介导p53的肿瘤抑制活性， 依赖性激酶（CDK）活性。本研究的总体目标是 从天然产物提取物高通量筛选中鉴定 植物或微生物来源的活性化合物，其恢复失去的p53功能 或替代WAF 1/CIP 1活性，并通过以下方式转化这些先导化合物： 合成化学转化成具有生物活性的类似物。Xenova Limited （实验室方案1）将从其天然提取物制备这些提取物 产品资源，并将进行ELISA筛选，设计和验证 关于PharmaGenics，Inc.（实验室计划2），以确定铅化合物 其可以：（A）恢复对p53突变体的功能性DNA结合活性;（B） 阻断p53/MDM 2相互作用;（C）抑制细胞周期蛋白CDK的活性 复杂. Xenova将从一个 放大发酵或植物提取物，如适用，并将进行 完整的结构分析。基于二级细胞的试验将 在Xenova和PharmaGenics，Inc.来确认 纯化的铅，并探讨其作用机制。这些测定 将由PharmaGenics，Inc.设计和验证。x射线晶体学 先导化合物/蛋白质靶复合物的研究将在 纪念斯隆-凯特林癌症中心的尼古拉·P。 Pavletich（实验室程序3），以生成以下信息 结构-活性关系和作用机制， 合理合成类似物的基础。这些类似物和 将测试原始电极导线在相关人类肿瘤中的体内有效性 由PharmaGenics，Inc.设计和执行的模型预计各国 这些数据将为临床试验的启动提供依据。

The tumor suppressor gene p53, which is among the most commonly mutated gene in human cancers, is a highly attractive target for the design of novel, mechanism-based anti-cancer agents that might have broadly utility. About half of all human cancers have been estimated to carry p53 mutations. In other cases p53 can be rendered functionally inactive by overexpression of proteins such as MDM2. p53 can induce the expression of WAF1/CIP1, which mediates the tumor suppressor activity of p53 by inhibiting cyclin- dependent kinase (CDK) activity. The overall goal of this research is to identify from high-throughput screening of natural product extracts of plant or microbial origin active compounds that restore lost p53 function or substitute for WAF1/CIP1 activity and to convert these leads by synthetic chemistry into pharmacologically active analogs. Xenova Limited (Laboratory Program 1) will prepare these extracts from their natural product resource and will carry out ELISA screens, designed and validated by PharmaGenics, Inc. (Laboratory Program 2), to identify lead compounds that can: (A) restore functional DNA binding activity to p53 mutants; (B) block the p53/MDM2 interaction; (C) inhibit the activity of a cyclin CDK complex. Xenova will purify milligram quantities of lead compound from a scaled-up fermentation or plant extract, as appropriate, and will conduct a complete structural analysis. Secondary cell-based assays will be employed at both Xenova and PharmaGenics, Inc. to confirm the activity of the purified leads and to probe their mechanism of action. These assays will be designed and validated by PharmaGenics, Inc. X-ray crystallography of the lead compound/protein target complex will be performed at the Memorial Sloan-Kettering Cancer Center in the laboratory of Nikola P. Pavletich (Laboratory Program 3) in order to generate information on structure-activity relationships and mechanism of action that will provide a basis for the rational synthesis of analogs. These analogs and the original leads will be tested for in vivo efficacy in relevant human tumor models designed and conducted by PharmaGenics, Inc. It is anticipated that these data will provide a basis for the initiation of clinical trials.