Inhibitors of Human Pal mitoyl Acyltransferase

描述(由申请人提供)：该计划的目标是开发新型的人棕榈酰转移酶(PATS)抑制剂，作为癌症治疗药物有效。PATs是抗癌药物开发的新靶点，因为它们在调节特定癌蛋白的亚细胞定位方面起着关键作用。最重要的是，某些形式的ras编码蛋白需要棕榈酰化才能定位于质膜，并具有转化细胞的能力。由于RAS蛋白的翻译后加工对其功能至关重要，催化这些加工步骤的酶被认为是抗癌药物的潜在靶点。到目前为止，抑制法尼化一直是这一治疗努力的主要焦点。然而，PATS可能是更好的靶标，因为棕榈酰化是一个动态过程，而法尼化不是。棕榈酰化抑制作用尚未被用于治疗的一个主要原因是哺乳动物的PAPT还没有得到分子和生物化学的表征。 最近对酿酒酵母棕榈酰化的研究已经确定了两个推定的PATP。利用酵母酶的序列，我们在脊椎动物中进行了同源搜索。基于序列和结构同源性，我们选择了一种名为HIP3的人类蛋白进行进一步研究，即确定该蛋白是否是真正的人类PAT(HPAT)。利用RNA干扰，我们已经证明HIP3具有PAT活性，并且它影响棕榈酰化蛋白质的亚细胞定位。在这项SBIR计划中，这些发现和我们之前发表的关于hPAT的工作将被用于开发hPAT的小分子抑制剂，以作为抗癌治疗药物进行评估。第一阶段项目将实现以下具体目标： 1.通过在已建立的ASAY和高通量酵母试验中筛选不同的小分子集合来鉴定抑制hPAT活性的化合物。 2.利用计算化学和药物化学对这些化合物进行优化。 3.测定铅PAT抑制剂的体外活性、体内毒性、药代动力学和抗肿瘤活性。

DESCRIPTION (provided by applicant): The goal of this program is to develop novel inhibitors of human palmitoyl acyltransferases (PATs) that are effective as cancer therapeutic agents. PATs represent new targets for anticancer drug development because of their pivotal roles in regulating the subcellular localization of specific oncoproteins. Most importantly, certain forms of ras-encoded proteins require palmitoylation for their targeting to the plasma membrane and for their ability to transform cells. Since post-translational processing of Ras proteins is critical for their function, the enzymes that catalyze these processing steps have been considered as potential targets for anticancer drugs. Inhibition of farnesylation has been the main focus of this therapeutic effort to date. However, the PATs may be even better targets, since palmitoylation is a dynamic process whereas farnesylation is not. A major reason that inhibition of palmitoylation has not yet been therapeutically exploited is that mammalian PATs have yet to be molecularly and biochemically characterized. Recent studies of palmitoylation in the yeast Saccharomyces cerevisiae have identified two putative PATs. Using the sequences of the yeast enzymes, we performed a search for homologues in vertebrates. Based on sequence and structural homologies, we selected a human protein called HIP3 for further study, i.e. to determine if this protein is an authentic human PAT (hPAT). Using RNA interference, we have shown that HIP3 has PAT activity, and that it affects the subcellular localization of palmitoylated proteins. In this SBIR program, these findings and our previously published work on hPATs will be used to develop small molecule inhibitors of hPATs to be evaluated as anticancer therapeutics. The following specific aims will be addressed in the Phase I project: 1. To identify compounds that inhibit hPAT activity by screening a diverse collection of small molecules in an established ass ay and a high-throughput yeast-based assay. 2. To use computational and medicinal chemistry to optimize these compounds. 3. To determine the in vitro activity, in vivo toxicity, pharmacokinetics and antitumor activity of lead PAT inhibitors.