Jun Zhang1, Xiaoli Lu2, Nan Wan2, Zichun Hua3, Zizheng Wang4, Hongbo Huang5, Min Yang5, Feng Wang6. 1. Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China, 210006; Taizhou People's Hospital, Taizhou, Jiangsu, China, 225300. 2. Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China, 210006. 3. State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing, Jiangsu, China, 210000. 4. Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China, 210006. Electronic address: zzwang136@aliyun.com. 5. Key Laboratory of Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 210463. 6. Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China, 210006; State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, Nanjing University, Nanjing, Jiangsu, China, 210000. Electronic address: fengwangcn@hotmail.com.
Abstract
UNLABELLED: Aminopeptidase N (APN) is selectively expressed on many tumors and the endothelium of tumor neovasculature, and may serve as a promising target for cancer diagnosis and therapy. Asparagine-glycine-arginine (NGR) peptides have been shown to bind specifically to the APN receptor and have served as vehicles for the delivery of various therapeutic drugs in previous studies. The purpose of this study was to synthesize and evaluate the efficacy of a (68)Ga-labeled NGR peptide as a new molecular probe that binds to APN. METHODS: NGR peptide was conjugated with 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) and labeled with (68)Ga at 95°C for 10 min. In vitro uptake and binding analysis was performed with A549 and MDA-MB231 cells. Biodistribution of (68)Ga-DOTA-NGR was determined in normal mice by dissection method. (68)Ga-DOTA-NGR PET was performed in A549 and MDA-MB231 xenografts, and included dynamic and static imaging. APN expression in tumors and new vasculatures was analyzed by immunohistochemistry. RESULTS: The radiochemical purity of (68)Ga-DOTA-NGR was 98.0% ± 1.4% with a specific activity of about 17.49 MBq/nmol. The uptake of (68)Ga-DOTA-NGR in A549 cells increased with longer incubation times, and could be blocked by cold DOTA-NGR, while no specific uptake was found in MDA-MB231 cells. In vivo biodistribution studies showed that (68)Ga-DOTA-NGR was mainly excreted from the kidney, and rapidly cleared from blood and nonspecific organs. MicroPET imaging showed that high focal accumulation had occurred in the tumor site at 1 h post-injection (pi) in A549 tumor xenografts. A significant reduction of tumor uptake was observed following coinjection with a blocking dose of DOTA-NGR, whereas only mild uptake was found in MDA-MB231 tumor xenografts. Tumor uptake, measured as the tumor/lung ratio, increased with time peaking at 12.58 ± 1.26 at 1.5 h pi. Immunohistochemical staining confirmed that APN was overexpressed on A549 cells and neovasculature. CONCLUSIONS: (68)Ga-DOTA-NGR was easily synthesized and showed favorable biodistribution and kinetics. (68)Ga-DOTA-NGR could also specifically bind to the APN receptor in vitro and in vivo, and might be a potential molecular probe for the noninvasive detection of APN-positive tumors and neovasculature.
UNLABELLED: Aminopeptidase N (APN) is selectively expressed on many tumors and the endothelium of tumor neovasculature, and may serve as a promising target for cancer diagnosis and therapy. Asparagine-glycine-arginine (NGR) peptides have been shown to bind specifically to the APN receptor and have served as vehicles for the delivery of various therapeutic drugs in previous studies. The purpose of this study was to synthesize and evaluate the efficacy of a (68)Ga-labeled NGR peptide as a new molecular probe that binds to APN. METHODS:NGR peptide was conjugated with 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) and labeled with (68)Ga at 95°C for 10 min. In vitro uptake and binding analysis was performed with A549 and MDA-MB231 cells. Biodistribution of (68)Ga-DOTA-NGR was determined in normal mice by dissection method. (68)Ga-DOTA-NGR PET was performed in A549 and MDA-MB231 xenografts, and included dynamic and static imaging. APN expression in tumors and new vasculatures was analyzed by immunohistochemistry. RESULTS: The radiochemical purity of (68)Ga-DOTA-NGR was 98.0% ± 1.4% with a specific activity of about 17.49 MBq/nmol. The uptake of (68)Ga-DOTA-NGR in A549 cells increased with longer incubation times, and could be blocked by cold DOTA-NGR, while no specific uptake was found in MDA-MB231 cells. In vivo biodistribution studies showed that (68)Ga-DOTA-NGR was mainly excreted from the kidney, and rapidly cleared from blood and nonspecific organs. MicroPET imaging showed that high focal accumulation had occurred in the tumor site at 1 h post-injection (pi) in A549 tumor xenografts. A significant reduction of tumor uptake was observed following coinjection with a blocking dose of DOTA-NGR, whereas only mild uptake was found in MDA-MB231 tumor xenografts. Tumor uptake, measured as the tumor/lung ratio, increased with time peaking at 12.58 ± 1.26 at 1.5 h pi. Immunohistochemical staining confirmed that APN was overexpressed on A549 cells and neovasculature. CONCLUSIONS: (68)Ga-DOTA-NGR was easily synthesized and showed favorable biodistribution and kinetics. (68)Ga-DOTA-NGR could also specifically bind to the APN receptor in vitro and in vivo, and might be a potential molecular probe for the noninvasive detection of APN-positive tumors and neovasculature.
Authors: Gopal Pathuri; Venkateshwar Madka; Andria F Hedrick; Stanley A Lightfoot; Vibhudutta Awasthi; Benjamin D Cowley; Chinthalapally V Rao; Hariprasad Gali Journal: Mol Pharm Date: 2014-07-10 Impact factor: 4.939
Authors: Janine Stucke-Ring; Julian Ronnacker; Caroline Brand; Carsten Höltke; Christoph Schliemann; Torsten Kessler; Lars Henning Schmidt; Saliha Harrach; Verena Mantke; Heike Hintelmann; Wolfgang Hartmann; Eva Wardelmann; Georg Lenz; Bernhard Wünsch; Carsten Müller-Tidow; Rolf M Mesters; Christian Schwöppe; Wolfgang E Berdel Journal: Oncotarget Date: 2016-12-13
Authors: Torsten Kessler; Ariane Baumeier; Caroline Brand; Michael Grau; Linus Angenendt; Saliha Harrach; Ursula Stalmann; Lars Henning Schmidt; Georg Gosheger; Jendrik Hardes; Dimosthenis Andreou; Johannes Dreischalück; Georg Lenz; Eva Wardelmann; Rolf M Mesters; Christian Schwöppe; Wolfgang E Berdel; Wolfgang Hartmann; Christoph Schliemann Journal: Transl Oncol Date: 2018-08-17 Impact factor: 4.243