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

多肽转运体-1(PEPT1)有望成为肿瘤选择性分子递送的靶点。由于几种含有苯丙氨酸的二肽能够被PEPT1识别为底物，我们设计并合成了一种由2-[^&lt；18&gt；F]氟烟酸和苯丙氨酸组成的肽能化合物(2-[^&lt；18&gt；F]FNA-Phe)作为肿瘤显像剂。体外测定了表达PEPT1的人胰腺癌细胞(ASPC-1)对PEPT1的摄取，表明2-FNA-Phe通过PEPT1被摄取到细胞内。将2-FNA-Phe静脉注射到荷AsPC-1的BALB/c裸鼠体内，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.