Synthesis and evaluation of an in vivo imaging probe for tumor based on the intracellular transporting system

肽转运蛋白-1（PEPT 1）有望成为肿瘤选择性分子递送的靶点。由于几种含苯丙氨酸的二肽被PEPT 1很好地识别为底物，因此我们设计并合成了由2-[^<18>F]氟烟酸和苯丙氨酸组成的肽能化合物（2-[^<18>F] FNA-Phe）作为用于肿瘤成像的PET探针。在体外测量表达PEPT 1的人胰腺肿瘤细胞（AsPC-1）的摄取，这证明2-[<18>1F] FNA-Phe通过PEPT 1被摄取到细胞中。当2-[1F<18>] FNA-Phe静脉注射到携带AsPC-1的BALB/c裸鼠时，肿瘤清晰可见。

Peptide transporter-1(PEPT1) is expected to be a target for the tumor-selective molecular delivery. Because several phenylalanine-containing dipeptides are well recognized by PEPT1 as substrates, we designed and synthesized a peptidergic compound consisting of 2-[^<18> F] fluoronicotinic acid and phenylalanine(2-[^<18> F] FNA-Phe) as a PET probe for tumor imaging. The uptake to human pancreatic tumor cells(AsPC-1) that expresses PEPT1 was measured in vitro, which demonstrated that 2-[^<18> F] FNA-Phe was taken up into cells via PEPT1. When 2-[^<18> F] FNA-Phe was intravenously injected to BALB/c nude mice bearing AsPC-1, the tumor was clearly visualized.