Targeting MLL3 histone methyltransferase

 描述（由申请人提供）：越来越多的证据表明，表观遗传途径在癌症的连续进展中起着不可或缺的作用。研究表明，许多表观遗传酶是癌症患者突变和失调的靶点。包括DNA甲基转移酶（DNMT）和组蛋白脱乙酰酶（HDAC）在内的几种关键表观遗传酶的抑制剂已被证明有助于基本理解酶各自活性的功能和在癌症表观遗传治疗中的应用。然而，开发组蛋白甲基转移酶抑制剂的抑制剂的努力仍在进行中。 它的婴儿期。该项目的总体目标是开发有效的和选择性的组蛋白甲基转移酶MLL3抑制剂。此外，我们还将开发一系列简便，灵敏和可重复的高通量筛选试验，以确定其他组蛋白甲基转移酶（HMT）活性的有效，选择性抑制剂。至少有六个MLL家庭HMT。MLL蛋白使用SAM辅因子甲基化组蛋白H3赖氨酸残基4，并与其他组蛋白修饰酶协同工作，以提供染色质改变和基因活化之间的机械联系;并通过募集各种H3K4“阅读器”蛋白来调节不同的生物过程。MLL突变和失调与几种人类疾病相关，包括各种癌症（白血病、淋巴瘤、结肠直肠癌、胃癌和肺癌）、肥胖和人类智能缺陷。由于由MLL介导的有趣的生物学及其与人类疾病的关系，开发可用作生物探针以及用于药物开发的先导分子的新型小分子抑制剂是令人感兴趣的。对于本申请，我们将集中我们的筛选工作的MLL3蛋白，虽然该测定应普遍适用于其他MLL家族HMT。该提案的具体目的是（1）开发MLL3抑制剂的高通量筛选和计数筛选，（2）开发二级测定，以定量效价并对高通量筛选中鉴定的候选命中化合物进行生物化学表征，以及（3）评估细胞测定和全基因组研究中化合物的靶向特异性。我们希望这些研究能够定义基于生物化学和细胞的检测方法，以筛选大的小分子文库，以鉴定MLL3组蛋白甲基转移酶的有效和选择性抑制剂，并获得一些靶向全局H3K4甲基化的泛MLL抑制剂。我们预计，这些研究将导致 鉴定有效的和选择性的第一代MLL3抑制剂，以进一步开发为化学探针。

 DESCRIPTION (provided by applicant): Accumulating evidence suggests that epigenetic pathways play an integral role in the sequential progression of cancer. It is shown that many epigenetic enzymes are targeted for mutation and deregulation in cancer patients. Inhibitors of several key epigenetic enzymes including DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) have proven to be instrumental for both basic understanding of the function of the respective activity of the enzymes and applications in cancer epigenetic therapy. However, efforts in development of inhibitors for histone methyltransferase inhibitors are still at its infancy. The overall goal of this project is to develop potent and selective inhibitors for histone methyltransferase MLL3. Furthermore, we will also develop a series of facile, sensitive and reproducible high-throughput screening assays ready to identify potent, selective inhibitors for other histone methyltransferase (HMT) activity. There are at least six MLL family HMTs. MLL proteins use the SAM cofactor to methylate histone H3 lysine residue 4 and work in concert with other histone modification enzymes to provide a mechanistic link between chromatin alteration and gene activation; and regulate different biological processes through recruitment of various H3K4 'reader' proteins. MLL mutations and dys-regulation have been correlated with several human diseases including various cancers (leukemia, lymphoma, colorectal, gastric and lung), obesity and human intelligent deficiency. Because of the interesting biology that is mediated by MLLs and their involvement to human diseases, it is of interest to develop novel small molecule inhibitors that might serve as biological probes as well as lead molecules for drug development. For this application, we will focus our screening efforts on the MLL3 protein, although the assay should be generally applicable to other MLL family HMTs. The specific aims of the proposal are to (1) Develop a high-throughput screen and counter screen for MLL3 inhibitors, (2) Develop an secondary assay to quantify the potency and to biochemically characterize candidate hit compounds identified in high-throughput screens, and (3) Assess compound on-target specificity in cellular assays and genome-wide studies. We expect these studies to define biochemical and cell based assays to screen large libraries of small molecules to identify potent and selective inhibitors of MLL3 histone methyltransferase, and to obtain some pan-MLL inhibitors that target global H3K4 methylation. We anticipate that these studies will result in the identification of potent and selective first-generation MLL3 inhibitors for further development as chemical probes.