Prostate-specific membrane antigen (PSMA), which is highly expressed in both localized and metastatic prostate cancer (PCa), is an ideal target for imaging and therapy of PCa. We previously reported radiolabeled asymmetric urea derivatives as a PSMA-targeting radiotracer for single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging. Here, based on these radiopharmaceutical probes, we designed a novel near-infrared (NIR) fluorescent imaging probe (800CW-SCE) by chemical conjugation between IRDye 800CW-Maleimide and an asymmetric urea compound, known as PSMA inhibitor, for optical imaging. In the in vitro cellular uptake study, 800CW-SCE was internalized into PSMA-positive PCa cells (LNCaP cells) but not into PSMA-negative PCa cells (PC-3 cells). Moreover, in the in vivo imaging study, the probe was highly accumulated in LNCaP tumors but not in PC-3 tumors, and remained in LNCaP tumors until 24 h after intravenous administration. These results suggest that the potent NIR conjugate may contribute to clinical intraoperative optical imaging.

前列腺特异性膜抗原（PSMA）在局部和转移性前列腺癌（PCa）中均高表达，是PCa成像和治疗的理想靶标。我们先前报道了放射性标记的不对称脲衍生物作为针对PSMA的放射性示踪剂，用于单光子发射计算机断层扫描（SPECT）和正电子发射断层扫描（PET）成像。在此，基于这些放射性药物探针，我们通过IRDye 800CW-马来酰亚胺和称为PSMA抑制剂的不对称脲化合物之间的化学偶联，设计了一种新型近红外（NIR）荧光成像探针（800CW-SCE），用于光学成像。在体外细胞摄取研究中，将800CW-SCE内在化为PSMA阳性PCa细胞（LNCaP细胞），而不是内化为PSMA阴性PCa细胞（PC-3细胞）。而且，在在体内成像研究中，该探针在LNCaP肿瘤中高度积累，而在PC-3肿瘤中却没有，并且一直保留在LNCaP肿瘤中，直到静脉给药后24 h。这些结果表明有效的近红外共轭物可能有助于临床术中光学成像。