Lo Pui-Chi, Chen Juan, Stefflova Klara, Warren Michael S, Navab Roya, Bandarchi Bizhan, Mullins Stefanie, Tsao Ming, Cheng Jonathan D, Zheng Gang
Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 1L7, Canada.
J Med Chem. 2009 Jan 22;52(2):358-68. doi: 10.1021/jm801052f.
Fibroblast activation protein (FAP) is a cell-surface serine protease highly expressed on cancer-associated fibroblasts of human epithelial carcinomas but not on normal fibroblasts, normal tissues, and cancer cells. We report herein a novel FAP-triggered photodynamic molecular beacon (FAP-PPB) comprising a fluorescent photosensitizer and a black hole quencher 3 linked by a peptide sequence (TSGPNQEQK) specific to FAP. FAP-PPB was effectively cleaved by both human FAP and murine FAP. By use of the HEK293 transfected cells (HEK-mFAP, FAP(+); HEK-vector, FAP(-)), systematic in vitro and in vivo experiments validated the FAP-specific activation of FAP-PPB in cancer cells and mouse xenografts, respectively. FAP-PPB was cleaved by FAP, allowing fluorescence restoration in FAP-expressing cells while leaving non-expressing FAP cells undetectable. Moreover, FAP-PPB showed FAP-specific photocytotoxicity toward HEK-mFAP cells whereas it was non-cytotoxic toward HEK-Vector cells. This study suggests that the FAP-PPB is a potentially useful tool for epithelial cancer detection and treatment.
成纤维细胞活化蛋白（FAP）是一种细胞表面丝氨酸蛋白酶，在人类上皮癌的癌症相关成纤维细胞上高度表达，但在正常成纤维细胞、正常组织和癌细胞上不表达。我们在此报告一种新型的FAP触发光动力分子信标（FAP-PPB），它由一种荧光光敏剂和一个通过FAP特异性肽序列（TSGPNQEQK）连接的黑洞猝灭剂3组成。FAP-PPB能被人FAP和鼠FAP有效切割。通过使用转染了HEK293的细胞（HEK-mFAP，FAP(+)；HEK-载体，FAP(-)），系统的体外和体内实验分别验证了FAP-PPB在癌细胞和小鼠异种移植瘤中对FAP的特异性激活。FAP-PPB被FAP切割，使得在表达FAP的细胞中荧光恢复，而不表达FAP的细胞则检测不到荧光。此外，FAP-PPB对HEK-mFAP细胞表现出FAP特异性光细胞毒性，而对HEK-载体细胞无细胞毒性。这项研究表明，FAP-PPB是一种用于上皮癌检测和治疗的潜在有用工具。
