UNLABELLED: Somatostatin receptor targeting of neuroendocrine tumors using radiolabeled somatostatin agonists is today an established method to image and treat cancer patients. However, in a study using an animal tumor model, somatostatin receptor antagonists were shown to label sst(2)- and sst(3)-expressing tumors in vivo better than agonists, with comparable affinity even though they are not internalized into the tumor cell. In the present study, we evaluated the in vitro binding of the antagonist (177)Lu-DOTA-pNO(2)-Phe-c (DCys-Tyr-DTrp-Lys-Thr-Cys) DTyrNH(2) ((177)Lu-DOTA-BASS) or the (177)Lu-DOTATATE agonist to sst(2)-expressing human tumor samples. METHODS: Forty-eight sst(2)-positive human tumor tissue samples (9 ileal carcinoids, 10 pheochromocytomas, 7 breast carcinomas, 10 renal cell carcinomas, and 12 non-Hodgkin lymphomas) were analyzed by in vitro receptor autoradiography for the expression of sst(2), comparing the binding capacity of (177)Lu-DOTA-BASS and (177)Lu-DOTATATE in successive tissue sections. The autoradiograms were quantitated using an electronic autoradiography detection system. RESULTS: In all cases, the radiolabeled antagonist bound to more receptor sites than did the agonist. The mean ratios of the antagonist (177)Lu-DOTA-BASS to the agonist (177)Lu-DOTATATE were 4.2 ± 0.5 in the 9 ileal carcinoids, 12 ± 3 in the 10 pheochromocytomas, 11 ± 4 in the 7 breast carcinomas, 5.1 ± 0.6 in the 10 renal cell carcinomas, and 4.8 ± 0.7 in the 12 non-Hodgkin lymphomas. CONCLUSION: The present in vitro human data, together with previous in vivo animal tumor data, are strong arguments indicating that sst(2) antagonists may be worth testing in vivo in patients in a wide range of tumors including nonneuroendocrine tumors.
UNLABELLED: Somatostatin receptor targeting of neuroendocrine tumors using radiolabeled somatostatin agonists is today an established method to image and treat cancerpatients. However, in a study using an animal tumor model, somatostatin receptor antagonists were shown to label sst(2)- and sst(3)-expressing tumors in vivo better than agonists, with comparable affinity even though they are not internalized into the tumor cell. In the present study, we evaluated the in vitro binding of the antagonist (177)Lu-DOTA-pNO(2)-Phe-c (DCys-Tyr-DTrp-Lys-Thr-Cys) DTyrNH(2) ((177)Lu-DOTA-BASS) or the (177)Lu-DOTATATE agonist to sst(2)-expressing humantumor samples. METHODS: Forty-eight sst(2)-positive humantumor tissue samples (9 ileal carcinoids, 10 pheochromocytomas, 7 breast carcinomas, 10 renal cell carcinomas, and 12 non-Hodgkin lymphomas) were analyzed by in vitro receptor autoradiography for the expression of sst(2), comparing the binding capacity of (177)Lu-DOTA-BASS and (177)Lu-DOTATATE in successive tissue sections. The autoradiograms were quantitated using an electronic autoradiography detection system. RESULTS: In all cases, the radiolabeled antagonist bound to more receptor sites than did the agonist. The mean ratios of the antagonist (177)Lu-DOTA-BASS to the agonist (177)Lu-DOTATATE were 4.2 ± 0.5 in the 9 ileal carcinoids, 12 ± 3 in the 10 pheochromocytomas, 11 ± 4 in the 7 breast carcinomas, 5.1 ± 0.6 in the 10 renal cell carcinomas, and 4.8 ± 0.7 in the 12 non-Hodgkin lymphomas. CONCLUSION: The present in vitro human data, together with previous in vivo animal tumor data, are strong arguments indicating that sst(2) antagonists may be worth testing in vivo in patients in a wide range of tumors including nonneuroendocrine tumors.
Authors: Sander M Bison; Mark W Konijnenberg; Marleen Melis; Stefan E Pool; Monique R Bernsen; Jaap J M Teunissen; Dik J Kwekkeboom; Marion de Jong Journal: Clin Transl Imaging Date: 2014-03-05
Authors: Lisa Bodei; Mark Kidd; Vikas Prasad; Richard P Baum; Ignat Drozdov; Irvin M Modlin Journal: Eur J Nucl Med Mol Imaging Date: 2014-12 Impact factor: 9.236
Authors: Giuseppe Lo Russo; Sara Pusceddu; Natalie Prinzi; Martina Imbimbo; Claudia Proto; Diego Signorelli; Milena Vitali; Monica Ganzinelli; Marco Maccauro; Roberto Buzzoni; Ettore Seregni; Filippo de Braud; Marina Chiara Garassino Journal: Tumour Biol Date: 2016-07-27