Targeting MYC promoter G-quadruplex for MYC inhibition by Indenoisoquinolines

项目总结 吲哚异喹啉靶向MYC启动子G-四链抑制MYC G-四链DNA是一种球形DNA二级结构，被认为是一类新的分子 抗癌药物的靶标。MYC是人类癌症中最常见的非调控基因之一，它有一种 其启动子中的DNA G4基序起到转录沉默的作用。结合并稳定的化合物 研究表明，在MYC启动子中形成的G-四联体可以显著降低癌症中的MYC水平 细胞。因此，MYC启动子G-四链(MycG4)是小分子抑制MYC的新靶点。 分子。然而，关于MycG4是如何由蛋白质调节的以及MycG4的发育情况，人们知之甚少。 靶向药物一直只专注于G4 DNA。而药物与DNA的相互作用可能不足以 抑制MYC，药物作用的有效机制可能涉及蛋白质-DNA相互作用，这是 类似于拓扑异构酶抑制剂。最近，我们发现吲哚异喹啉，一种临床上的 测试支架具有优异的类药物性能，是强大的MycG4结合剂和有效的MYC抑制剂。我们 我还发现，DDX5解旋酶活跃地解开MycG4，并与myc基因密切相关 转录激活。这些结果为有效地降低MYC的监管提供了新的关键见解 靶向MycG4转录及其与DDX5的相互作用。我们的中心假设是 吲哚异喹啉通过与MYC启动子G-四链结合有效抑制MYC转录 干扰DDX5-MycG4相互作用。总的目标是确定其分子机制。 吲哚异喹啉对MYC的有效抑制，建立结构-活性关系(SAR)，以及 发现用于临床前试验的吲哚异喹啉铅。长期的研究目标是开发出有效的 吲哚异喹啉MYC抑制剂作为抗癌新药。具体目标是：1)结构性 MycG4-吲哚异喹啉络合物的表征。2)建立化合物文库，确定 吲哚异喹啉类化合物结合MycG4并抑制MYC。3)确定MycG4互动的效果 吲哚异喹啉对MYC启动子G4 DDX5展开的影响及其与MYC的关系 压制。4)设计并合成了优化的吲哚异喹啉类化合物，用于抑制MYC 基于结构的合理方法；建立MycG4结合和抑制DDX5展开的SAR。这个 这项工作的预期结果是确定吲哚异喹啉类药物用于MycG4靶向的SAR， 抑制DDX5-MycG4相互作用有效抑制MYC的论证和铅的发现 用于未来临床前试验的化合物。结果将产生重要的积极影响，因为它们 为开发具有MYC靶向活性的新型吲哚异喹啉抗癌药物奠定基础。

PROJECT SUMMARY Targeting MYC promoter G-quadruplex for MYC inhibition by Indenoisoquinolines G-quadruplex (G4) DNA is a globular DNA secondary structure and considered as a new class of molecular targets for anticancer drugs. MYC, one of the most commonly deregulated genes in human cancers, has a DNA G4 motif in its promoter that functions as a transcriptional silencer. Compounds that bind to and stabilize the G-quadruplex formed in the MYC promoter have been shown to significantly lower MYC levels in cancer cells. Thus, the MYC promoter G-quadruplex (MycG4) represents a novel target for MYC inhibition by small molecules. However, little is known about how MycG4 is regulated by proteins and development of MycG4- targeting drugs has been focused solely on G4 DNA. Whereas drug-DNA interactions may be insufficient for MYC inhibition, the effective mechanism of drug action could involve protein-DNA interactions, which is analogous to topoisomerase inhibitors. Very recently, we have discovered that indenoisoquinolines, a clinically tested scaffold with excellent drug-like properties, are strong MycG4 binders and potent MYC inhibitors. We have also discovered that the DDX5 helicase actively unfolds MycG4 and is critically involved in MYC gene transcriptional activation. These results provide new and critical insights to effectively downregulate MYC transcription by targeting MycG4 and its interactions with DDX5. Our central hypothesis is that indenoisoquinolines effectively suppress MYC transcription by binding to the MYC promoter G-quadruplex and disrupting DDX5-MycG4 interactions. The overall objective is to determine the molecular mechanism of effective MYC inhibition by indenoisoquinolines, establish the structure–activity relationships (SAR), and discover lead indenoisoquinolines for preclinical testing. The long-term research goal is to develop potent indenoisoquinoline MYC inhibitors as new anticancer drugs. The specific aims are: 1) Structural characterization of the MycG4-indenoisoquinoline complexes. 2) Establishing a compound library to determine indenoisoquinolines that bind MycG4 and inhibit MYC. 3) Determining the effect of MycG4-interactive indenoisoquinolines on DDX5 unfolding of the MYC promoter G4 and how this correlates with MYC suppression. 4) Designing and synthesizing optimized indenoisoquinolines for MYC suppression using structure-based rational approach; establishing SAR for MycG4-binding and inhibition of DDX5 unfolding. The expected outcome of this work is a determination of the SAR of indenoisoquinolines for MycG4-targeting, demonstration of the effective MYC suppression by inhibiting DDX5-MycG4 interaction, and discovery of lead compounds for future preclinical testing. The results will have an important positive impact because they lay the groundwork to develop new indenoisoquinoline anticancer drugs with MYC-targeted activity.