Structure Based Discovery of AKT Inhibitors

描述（由申请人提供）： AKT 1（蛋白激酶B）是v-akt癌基因的细胞同源物， 代表多基因蛋白的三种同工型之一-丝氨酸/苏氨酸 激酶家族一种或多种Akt的基因扩增和/或过表达 在胃癌、脑癌、乳腺癌、前列腺癌 卵巢和胰腺。高AKT活性在具有以下特征的肿瘤中特别明显： 肿瘤抑制因子PTEN的突变或缺失，其主要功能是 作为磷酸肌醇3-磷酸酶。野生型PTEN在人中的表达 肿瘤细胞系或人胰腺癌中AKT 2反义cDNA 异种移植物分别显著减少细胞和肿瘤生长，表明 AKT作为治疗靶点的效用。其主要目标是 因此，应用是开发AKT的亚型特异性抑制剂 通过使用分子建模和化合物的虚拟筛选， 文库与基于同源二聚化的独特筛选测定偶联， AKT的N-末端结构域（AH结构域）。先导药物 将评估在该筛选中鉴定的细胞抑制肿瘤生长的能力。 细胞生长，诱导凋亡和阻断AKT激活， 转磷酸作用本申请将解决以下假设： 中断AKT二聚化将抑制其活性和下游 导致抑制肿瘤细胞增殖的效应子途径， 凋亡的激活。这一假设将通过以下方式加以解决： 具体目标：1）完善我们的AKT 1模型，并将其用于构建 AH结构域相互作用产生的同源二聚体，2）为了鉴定 AKT AH结构域中位于AKT的界面处的结构区域 同源二聚体，并使用化合物文库的虚拟筛选（NCI，ACD）， 鉴定能够与这些二聚化相互作用小分子 3）为了测试那些显示最佳评分函数的化合物， 结合AH结构域以抑制AKT二聚化的能力，和 从而在体外激活AKT。根据后面的结果， 结构-活性关系（SAR）数据将由化学 修饰先导分子以提高化合物活性。 将对AKT 1 AH结构域结合口袋的活性结构进行建模。 以迭代的方式用于指导化合物合成以及建议 可能的化合物库将使用组合化学产生 方法.

DESCRIPTION (provided by applicant): AKT1 (protein kinase B) is the cellular homolog of the v-akt oncogene, and represents one of three isoforms of a multigene protein-serine/threonine kinase family. Gene amplification and/or overexpression of one or more Akt isoforms have been noted in cancers of the stomach, brain, breast, prostate, ovary and pancreas. High AKT activity is particularly evident in tumors with mutations or deletion of the tumor suppressor, PTEN, which functions primarily as a phosphoinositide 3-phosphatase. Expression of wild-type PTEN in human tumor cell lines or an AKT2 antisense cDNA in a human pancreatic carc/noma xenograft dramatically reduced cell and tumor growth, respectively, suggesting the utility of AKT as a therapeutic target. The broad objective of this application, therefore, is to develop isoform-specific inhibitors of AKT through the use of molecular modeling and virtual screening of compound libraries coupled with a unique screening assay based on homodimerization of the/soform-specific N-terminal donaain (AH domain) of AKT. Lead drugs identified in this screen will be assessed for their ability to inhibit tumor cell growth, induce apoptosis and block AKT activation via transphosphorylation. This application will address the hypothesis that interruption of AKT dimerization will inhibit its activity and downstream effector pathways leading to inhibition of tumor cell proliferation and activation of apoptosis. This hypothesis will be addressed by the following Specific Aims: 1) To refine our AKT1 model and to use it in construction of the homodimer resulting from interaction of the AH domains, 2) To identify structural regions in the AKT AH domain located at the interface of the AKT homodimer and to use virtual screening of compound libraries (NCI, ACD) to identify small molecules capable of interacting with these dimerization regions, and 3) To test those compounds showing the best scoring function for binding to the AH domain for their ability to inhibit AKT dimerization, and thus, activation of AKT in vitro. Based upon the latter results, structure-activity relationship (SAR) data will be generated by chemical modificationm of the lead molecules in order to improve compound activity. Modeling of active structures to the AKT1 AH domain binding pocket will be used in an iterative manner to guide compound synthesis as well as to suggest possible compound libraries to be created using combinatorial chemistry methods.