Non-nucleoside inhibitors of DNA methyl transferase I

描述（由申请人提供）：获得基因组改变是人类癌症的定义特征。癌症化疗依赖于细胞死亡或凋亡途径来根除含有这些改变的细胞。DNA中适当的甲基化水平的维持在正常的DNA复制和有丝分裂过程中是必要的。正确和适当的甲基化的破坏导致与肿瘤细胞中的转录沉默相关的非诱变性变化。细胞凋亡途径中基因的转录沉默沿着会消除化疗的效果，并且这种肿瘤对经典疗法是难治的，并且与不良预后相关。DNA中胞嘧啶的表观遗传甲基化发生在基因启动子内CpG二核苷酸重复序列的密集簇中的CpG位点处，并由DNA甲基转移酶（Dnmt）催化。能够抑制Dnmt的治疗剂可以重新激活因高甲基化而沉默的基因，因此，设计和开发新型Dnmt抑制剂是一个有价值的目标，特别是当沉默的基因保持完整和功能时。我们已经构建了独特的天然产物衍生物库的基础上，天然产物分离，组合生物合成和平行组合合成。我们的库由保留天然产物的拓扑和立体化学复杂性但制备简单的结构组成。在针对人Dnmt-1酶筛选我们的文库时，我们发现具有异吲哚啉酮核心骨架的化合物是优异的抑制剂，Ki值低至20微摩尔。在本申请中，我们试图证明我们可以开发Dnmt-1的有效和选择性抑制剂。我们进一步试图证明，我们的抑制剂引起模型表观遗传沉默基因，人MLH 1的重新激活。

DESCRIPTION (provided by applicant): The acquisition of genomic alterations is a defining feature of human cancers. Cancer chemotherapy relies upon the cell death or apoptotic pathway to eradicate cells containing these alterations. The maintenance of appropriate methylation levels in DNA is necessary during normal DNA replication and mitosis. Disruption of correct and appropriate methylation leads to non-mutagenic changes associated with transcriptional silencing in tumor cells. Transcriptional silencing of genes along the apoptotic pathway abrogates the efficacy of chemotherapy and such tumors are refractory to classical therapy and associated with a poor prognosis. Epigenetic methylation of cytosine in DNA occurs at CpG sites in dense clusters of CpG dinucleotide repeats within gene promoters and is catalyzed by DNA methyl transferase enzymes (Dnmt's). Therapeutics that can inhibit Dnmt can reactivate genes silenced by hypermethylation, therefore, the design and development of novel Dnmt inhibitors is a worthy goal especially as the silenced genes remain intact and functional. We have constructed unique libraries of natural product derivatives based upon natural product isolation, combinatorial biosynthesis and parallel combinatorial synthesis. Our libraries are composed of structures that retain the topological and stereochemical complexity of natural products yet are straightforward to prepare. In screening our libraries against the human Dnmt-1 enzyme we discovered that compounds with an isoindolinone core scaffold were excellent inhibitors with Ki values as low as 20 micromolar. In this application we seek to demonstrate that we can develop potent and selective inhibitors of Dnmt-1. We further seek to demonstrate that our inhibitors cause reactivation of a model epigenetically silenced gene, human MLH1.