Novel HDAC-interacting proteins that regulate breast cancer cell growth

描述（由申请人提供）：染色质结构在维持适当的基因表达中起着关键作用。组蛋白上共价修饰形式的表观遗传变化，包括乙酰化，有助于调节染色质结构和基因表达。组蛋白脱乙酰基酶（HDAC）是一组酶，催化组蛋白中乙酰基的去除，这通常会导致基因抑制。由于癌症可以由控制细胞生长的基因表达的异常变化引起，HDAC已成为化疗药物的重要靶点。组蛋白去乙酰化酶抑制剂目前正在临床试验中进行测试，以治疗几种类型的癌症，包括乳腺癌。这些药物有效地优先停止癌细胞的生长超过正常细胞。然而，目前使用的HDAC抑制剂靶向HDAC的催化位点，并且不区分人类中的几种结构相似的HDAC。因此，这些HDAC抑制剂由于其缺乏对个体HDAC的特异性而表现出不期望的副作用。单个HDAC存在于多亚基蛋白质复合物中，并且一些已知的实例表明这些HDAC相关蛋白质中的一些与特定HDAC的催化活性相关并且是其所需的。因此，作为抑制HDAC酶本身的替代方案，抑制HDAC相互作用蛋白应该提供同样有效但更特异的治疗。该提案将鉴定和功能表征与HDAC 1或HDAC 3特异性相关的蛋白质，这些蛋白质可以通过调节其特异性相关的HDAC活性来控制乳腺癌增殖。 具体目标：1。进行蛋白质组学分析，以识别人类细胞中与HDAC1和HDACS相关的蛋白质。生物化学鉴定HDAC及其差异相关蛋白所在的亚基组成和不同复合物的数量。2.确定哪些HDAC相互作用蛋白对HDAC活性很重要，并确定HDAC1和HDACS相关蛋白如何影响其相关HDAC复合物的活性和完整性。3.使用siRNA靶向浸润性乳腺癌细胞中含有HDAC1和3的复合物，并鉴定哪些蛋白质在被废除时会阻止癌细胞生长。与公共卫生的相关性：目前的许多抗癌药物由于其靶点的特异性差而在患者中显示出不希望的毒副作用。该提案旨在为化疗药物寻找更特异的蛋白质靶点，以降低这些药物的毒性。

DESCRIPTION (provided by applicant): Chromatin structure plays a critical role in maintaining proper gene expression. Epigenetic changes in the form of covalent modifications on histones including acetylation help regulate chromatin structure and gene expression. One group of enzymes, the histone deacetylases (HDACs) catalyze the removal of acetyl groups from histones which generally leads to gene repression. Since cancer can be caused by aberrant changes in the expression of genes that control cell growth, HDACs have become important targets of chemotherapeutics. Histone deacetylase inhibitors are currently being tested in clinical trials to treat several types of cancers, including breast cancer. These drugs are effective at preferentially halting growth of cancer cells over normal cells. However, the HDAC inhibitors currently in use target the catalytic sites of HDACs and do not discriminate among the several structurally similar HDACs in humans. Thus these HDAC inhibitors exhibit undesirable side effects due to their lack of specificity for individual HDACs. Individual HDACs reside in multi-subunit protein complexes, and a few known examples show that some of these HDAC-associated proteins are associated with and required for the catalytic activity of a particular HDAC. Therefore, as an alternative to inhibiting the HDAC enzymes themselves, inhibiting HDAC- interacting proteins should provide just as effective, but more specific treatment. This proposal will identify and functionally characterize proteins specifically associated with either HDAC1 or HDAC3 that can control breast cancer proliferation through modulation of their specific associated HDAC's activity. Specific Aims: 1. Perform proteomics analysis to identify proteins associated with HDAC1 and HDACS in human cells. Biochemically identify the subunit composition and the number of distinct complex(es) the HDACs and their differentially associated proteins reside in. 2. Identify which HDAC-interacting proteins are important for HDAC activity and determine how HDAC1- and HDACS-associated proteins affect the activity and integrity of their associated HDAC complex. 3. Target HDAC1- and 3-containing complexes in invasive breast cancer cells using siRNAs and identify which proteins, when abrogated, halt cancer cell growth. Relevance to Public Health: Many current anti-cancer drugs show unwanted toxic side effects in patients due to poor specificity of these drugs for their targets. This proposal seeks to find more specific protein targets for chemotherapeutics which should decrease the toxicity of these drugs.