Koch Peter D, Quintana Jeremy, Ahmed Maaz, Kohler Rainer H, Weissleder Ralph
Center for Systems Biology, Massachusetts General Hospital, 185 Cambridge St, CPZN 5206, Boston, MA 02114.
Department of Systems Biology, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115.
Adv Ther (Weinh). 2021 May;4(5). doi: 10.1002/adtp.202000290. Epub 2021 Mar 12.
Multiple potent covalent inhibitors for mutant KRAS G12C have been described and some are in clinical trials. These small molecule inhibitors potentially allow for companion imaging probe development, thereby expanding the chemical biology toolkit to investigate mutant KRAS biology. Herein, we synthesized and tested a series of fluorescent companion imaging drugs (CID) for KRAS G12C, using two scaffolds, ARS-1323 and AMG-510. We created four fluorescent derivatives of each by attaching BODIPY dyes. We found that two fluorescent derivatives (BODIPY FL and BODIPY TMR) of ARS-1323 bind mutant KRAS and can be used for biochemical binding screens. Unfortunately, these drugs could not be used as direct imaging agents in cells, likely because of non-specific membrane labeling. To circumvent this challenge, we then used a two step procedure in cancer cells where an ARS-1323 alkyne is used for target binding followed by fluorescence imaging after click chemsitry with picolyl azide Alexa Fluor 647. We show that this approach can be used to image mutant KRAS G12C directly in cells. Given the current lack of mutant KRAS G12C specific antibodies, these reagents could be useful for specific fluorescence imaging.
已经描述了多种针对突变型KRAS G12C的强效共价抑制剂，其中一些正在进行临床试验。这些小分子抑制剂有可能推动伴随成像探针的开发，从而扩展化学生物学工具集以研究突变型KRAS生物学。在此，我们使用ARS-1323和AMG-510这两种支架合成并测试了一系列用于KRAS G12C的荧光伴随成像药物（CID）。我们通过连接BODIPY染料为每种支架创建了四种荧光衍生物。我们发现ARS-1323的两种荧光衍生物（BODIPY FL和BODIPY TMR）能结合突变型KRAS，可用于生化结合筛选。遗憾的是，这些药物不能用作细胞中的直接成像剂，可能是由于非特异性膜标记。为了克服这一挑战，我们随后在癌细胞中采用两步法，即先用ARS-1323炔烃进行靶标结合，然后在用叠氮甲基吡啶Alexa Fluor 647进行点击化学后进行荧光成像。我们证明这种方法可用于在细胞中直接对突变型KRAS G12C进行成像。鉴于目前缺乏突变型KRAS G12C特异性抗体，这些试剂可用于特异性荧光成像。
