Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Department of Chemistry, Indian Institute of Science Education and Research, Bhopal 462066, India.
Biochemistry. 2022 Jun 7;61(11):1064-1076. doi: 10.1021/acs.biochem.2c00116. Epub 2022 May 18.
G-Quadruplex (G4) structures play a pivotal role in diverse biological functions, including essential processes, such as telomere maintenance and gene regulation. G4 structures formed in functional regions of genomes are actively pursued toward therapeutics and are targeted by small-molecule ligands that alter their structure and/or stability. Herein, we report the synthesis of bisindolylmaleimide-based () ligands, which preferentially stabilize parallel G4 structures of and oncogenes over the telomeric G4 and duplex DNAs. The preferential stabilization of parallel G4s with ligands is further validated by the DNA polymerase stop assay, where stop products were only observed for templates containing the G4 sequence. Nuclear magnetic resonance (NMR) titration studies indicate that the lead ligand forms a 2:1 complex with G4 DNA with a of 38 ± 5 μM. The ligand stacks at the 5' and 3' quartets, with molecular modeling and dynamics studies supporting the proposed binding mode. The ligand is cytotoxic to HeLa cells and downregulates gene expression. Collectively, the results present bisindolylmaleimide scaffolds as novel and powerful G4 targeting agents.
G-四链体（G4）结构在多种生物功能中发挥着关键作用，包括端粒维持和基因调控等基本过程。在基因组的功能区域形成的 G4 结构被积极地用于治疗，并成为小分子配体的靶向目标，这些配体可以改变它们的结构和/或稳定性。在此，我们报告了基于双吲哚马来酰亚胺的（）配体的合成，这些配体优先稳定和癌基因中的平行 G4 结构，而不是端粒 G4 和双链 DNA。通过 DNA 聚合酶停止测定进一步验证了 配体对平行 G4 的优先稳定，只有含有 G4 序列的模板才会观察到停止产物。核磁共振（NMR）滴定研究表明，先导配体与 G4 DNA 形成 2:1 复合物，其为 38±5μM。配体在 5'和 3'四联体处堆积，分子建模和动力学研究支持所提出的结合模式。该配体对 HeLa 细胞具有细胞毒性，并下调基因表达。总的来说，这些结果表明双吲哚马来酰亚胺支架是新型有效的 G4 靶向剂。
