6-[18HF]Fluoro-2-alkoxynicotinoyl substituted Lys-C(O)-Glu derivatives were identified as efficient imaging probes for PSMA expressing tissues in comparison to other known PSMA specific ligands like [18F]DCFPyL, [68Ga]HBED-CC-PSMA, [18F]PSMA-1007 and [A118F]HBED-CC-PSMA. Unexpectedly, the 6-[18F]fluoro-2-alkoxy and 6-[18F]fluoro-4- alkoxy substituted analogs showed significant differences in accumulation in PSMA expressing prostate tumor cells. Whereas the 2-alkoxy derivative showed cellular uptake values higher than [18F]DCFPyL, the cellular uptake of the corresponding 4-alkoxy substituted derivative was significantly lower. Furthermore, in vivo PET studies with 2- alkoxy-substituted probes demonstrated excellent visualization of PSMA positive ganglia with extremely high target to background ratio. In contrast, the 4-alkoxy substituted derivatives showed less favorable biodistribution with significantly lower uptake in PSMA positive tissues. Especially, the 18F-labeled 2-methoxy derivate ((2S)-2-([(1 S)- 1 -carboxy-5- [(6-[18F] fluoro-2-methoxypyridin-3-yl)formamido]pentyl ]carbamoyl} -amino)pentanedioic acid) demonstrated exceptional clinical efficiency in detecting small PCa lesions, including those which could not be visualized with [68Ga]HBED-CC-PSMA representing currently the gold standard for the diagnosis of recurrent PCa. Furthermore, this probe is easily accessible on a preparative scale in commercially available automated synthesis modules like GE FASTlab and TRACERlab FX N Pro. Consequently, the novel probe is a valuable tool for the visualization of ganglia and reendothelialization as well as for the diagnosis of glioma, neuropathic pain and atherosclerotic plaques.
6-[18HF]
氟-2-烷氧基烟酰基取代的Lys-C(O)-Glu衍
生物被确定为与其他已知PSMA特异性
配体(如[18F]DCFPyL、[68Ga]HBED-CC-PSMA、[18F]PSMA-1007和[A118F]HBED-CC-PSMA)相比,在PSMA表达组织中作为高效成像探针。令人意外的是,6-[18F]
氟-2-烷氧基和6-[18F]
氟-4-烷氧基取代的类似物在PSMA表达的前列腺肿瘤细胞中的积累显示出显著差异。而2-烷氧基衍
生物的细胞摄取值高于[18F]DCFPyL,相应的4-烷氧基取代衍
生物的细胞摄取则明显较低。此外,在使用2-烷氧基取代探针进行体内PET研究时,显示出对PSMA阳性神经节的优秀可视化效果,具有极高的靶向背景比。相比之下,4-烷氧基取代的衍
生物在PSMA阳性组织中的摄取较低,
生物分布不太理想。特别是,18F标记的2-甲氧基衍
生物((2S)-2-([(1 S)-1-羧基-5-[(6-[18F]
氟-
2-甲氧基吡啶-3-基)甲酰]戊基]
氨基}-
氨基)
戊二酸)在检测小型前列腺癌病灶方面表现出卓越的临床效率,包括那些无法通过[68Ga]HBED-CC-PSMA可视化的病灶,后者目前代表着复发前列腺癌诊断的黄
金标准。此外,这种探针在商业化可获得的自动合成模块(如GE FASTlab和
TRACERlab FX N Pro)中易于制备,因此这种新型探针是可视化神经节和内皮再生以及诊断胶质瘤、神经病性疼痛和动脉粥样硬化斑块的宝贵工具。