Milite Ciro, Barresi Elisabetta, Da Pozzo Eleonora, Costa Barbara, Viviano Monica, Porta Amalia, Messere Anna, Sbardella Gianluca, Da Settimo Federico, Novellino Ettore, Cosconati Sandro, Castellano Sabrina, Taliani Sabrina, Martini Claudia
Dipartimento di Farmacia, Università di Salerno , Via Giovanni Paolo II 132, 84084 Fisciano, Salerno, Italy.
Dipartimento di Farmacia, Università di Pisa , Via Bonanno 6, 56126 Pisa, Italy.
J Med Chem. 2017 Sep 28;60(18):7897-7909. doi: 10.1021/acs.jmedchem.7b01031. Epub 2017 Sep 15.
The quinazoline class was exploited to search for a new translocator protein (TSPO) fluorescent probe endowed with improved affinity and residence time (RT). Computational studies on an "in-house" collection of quinazoline derivatives, featuring highly steric demanding groups at the amide nitrogen, suggested that, despite their molecular extension, these ligands are still easily lodged in the TSPO binding site. Binding assays supported this hypothesis, highlighting a low nanomolar/subnanomolar affinity of these ligands, together with a higher RT of the representative compound 11 with respect to our previously reported indole-based fluorescent probe. Thanks to the amenability of the amide nitrogen atom to be substituted with bulky groups, we developed quinazoline-based imaging tools by fluorescently labeling the scaffold at this position. Probes with relevant TSPO affinity, favorable spectroscopic properties, and improved RT were identified. The results from fluorescence microscopy showed that these probes specifically labeled the TSPO at the mitochondrial level in the U343 cell line.
喹唑啉类化合物被用于寻找一种新型的转运体蛋白（TSPO）荧光探针，该探针具有更高的亲和力和驻留时间（RT）。对“内部”喹唑啉衍生物库进行的计算研究表明，尽管这些配体在酰胺氮上具有高度空间需求基团，分子尺寸较大，但它们仍能轻松地嵌入TSPO结合位点。结合实验支持了这一假设，突出了这些配体具有低纳摩尔/亚纳摩尔亲和力，以及代表性化合物11相对于我们之前报道的基于吲哚的荧光探针具有更长的驻留时间。由于酰胺氮原子易于被庞大基团取代，我们通过在该位置对骨架进行荧光标记，开发了基于喹唑啉的成像工具。鉴定出了具有相关TSPO亲和力、良好光谱性质和改善驻留时间的探针。荧光显微镜检查结果表明，这些探针在U343细胞系中线粒体水平上特异性标记了TSPO。
