Department of Chemistry, University of Cambridge, Cambridge, UK.
J Am Chem Soc. 2011 Mar 2;133(8):2658-63. doi: 10.1021/ja109474c. Epub 2011 Feb 4.
There is considerable interest in the structure and function of G-quadruplex nucleic acid secondary structures, their cellular functions, and their potential as therapeutic targets. G-Quadruplex sequence motifs are prevalent in gene promoter regions and it has been hypothesized that G-quadruplex structure formation is associated with the transcriptional status of the downstream gene. Using a functional cell-based assay, we have identified two novel G-quadruplex ligands that reduce the transcription of a luciferase reporter driven from the G-quadruplex-containing c-KIT promoter. We have further shown that endogenous c-KIT expression in a human gastric carcinoma cell line is also reduced on treatment with these molecules. Biophysical analysis using surface plasmon resonance has shown that these molecules preferentially bind with high affinity to one of the two G-quadruplex sequences in the c-KIT promoter over double-stranded DNA. This work highlights the utility of cell-based reporter assays to identify new G-quadruplex binding molecules that modulate transcription and identifies benzo[a]phenoxazine derivatives as potential antitumor agents.
人们对 G-四链体核酸二级结构的结构和功能、它们的细胞功能以及它们作为治疗靶点的潜力非常感兴趣。G-四链体序列基序在基因启动子区域很常见，人们假设 G-四链体结构的形成与下游基因的转录状态有关。使用基于功能的细胞测定法，我们已经鉴定出两种新型 G-四链体配体，它们可以降低来自包含 G-四链体的 c-KIT 启动子的荧光素酶报告基因的转录。我们进一步表明，在用这些分子处理后，人胃腺癌细胞系中的内源性 c-KIT 表达也降低。使用表面等离子体共振的生物物理分析表明，这些分子优先以高亲和力与 c-KIT 启动子中的两个 G-四链体序列之一结合，而不是与双链 DNA 结合。这项工作强调了基于细胞的报告基因测定法在鉴定新的 G-四链体结合分子以调节转录方面的实用性，并确定苯并[a]吩恶嗪衍生物为潜在的抗肿瘤药物。
