Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo
Girentuximab (cG250) targets carbonic anhydrase IX (CAIX), a protein which is expressed on the surface of most renal cancer cells (RCCs). cG250 labeled with <sup>177</sup>Lu has been used in clinical trials for radioimmunotherapy (RIT) of RCCs. In this work, an extensive characterization...
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MDPI AG
2018-11-01
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| Series: | Pharmaceuticals |
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| Online Access: | https://www.mdpi.com/1424-8247/11/4/132 |
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| author | Tais Basaco Stefanie Pektor Josue M. Bermudez Niurka Meneses Manfred Heller José A. Galván Kayluz F. Boligán Stefan Schürch Stephan von Gunten Andreas Türler Matthias Miederer |
| author_facet | Tais Basaco Stefanie Pektor Josue M. Bermudez Niurka Meneses Manfred Heller José A. Galván Kayluz F. Boligán Stefan Schürch Stephan von Gunten Andreas Türler Matthias Miederer |
| author_sort | Tais Basaco |
| collection | DOAJ |
| description | Girentuximab (cG250) targets carbonic anhydrase IX (CAIX), a protein which is expressed on the surface of most renal cancer cells (RCCs). cG250 labeled with <sup>177</sup>Lu has been used in clinical trials for radioimmunotherapy (RIT) of RCCs. In this work, an extensive characterization of the immunoconjugates allowed optimization of the labeling conditions with <sup>177</sup>Lu while maintaining immunoreactivity of cG250, which was then investigated in in vitro and in vivo experiments. cG250 was conjugated with S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA(SCN)) by using incubation times between 30 and 90 min and characterized by mass spectrometry. Immunoconjugates with five to ten DOTA(SCN) molecules per cG250 molecule were obtained. Conjugates with ratios less than six DOTA(SCN)/cG250 had higher in vitro antigen affinity, both pre- and postlabeling with <sup>177</sup>Lu. Radiochemical stability increased, in the presence of sodium ascorbate, which prevents radiolysis. The immunoreactivity of the radiolabeled cG250 tested by specific binding to SK-RC-52 cells decreased when the DOTA content per conjugate increased. The in vivo tumor uptake was < 10% ID/g and independent of the total amount of protein in the range between 5 and 100 µg cG250 per animal. Low tumor uptake was found to be due to significant necrotic areas and heterogeneous CAIX expression. In addition, low vascularity indicated relatively poor accessibility of the CAIX target. |
| first_indexed | 2024-12-12T14:03:59Z |
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| institution | Directory Open Access Journal |
| issn | 1424-8247 |
| language | English |
| last_indexed | 2024-12-12T14:03:59Z |
| publishDate | 2018-11-01 |
| publisher | MDPI AG |
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| series | Pharmaceuticals |
| spelling | doaj.art-44d0386473a645bb8d58fbf2d2b7e3fc2022-12-22T00:22:16ZengMDPI AGPharmaceuticals1424-82472018-11-0111413210.3390/ph11040132ph11040132Evaluation of Radiolabeled Girentuximab In Vitro and In VivoTais Basaco0Stefanie Pektor1Josue M. Bermudez2Niurka Meneses3Manfred Heller4José A. Galván5Kayluz F. Boligán6Stefan Schürch7Stephan von Gunten8Andreas Türler9Matthias Miederer10Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, SwitzerlandClinic for Nuclear Medicine, University Medical Center Mainz, 55131 Mainz, GermanyDepartment of Chemistry and Biochemistry, University of Bern, 3012 Bern, SwitzerlandDepartment of Chemistry and Biochemistry, University of Bern, 3012 Bern, SwitzerlandDepartment for Biomedical Research (DBMR), University of Bern, 3010 Bern, SwitzerlandInstitute of Pathology, University of Bern, 3010 Bern, SwitzerlandInstitute of Pharmacology (PKI), University of Bern, 3010 Bern, SwitzerlandDepartment of Chemistry and Biochemistry, University of Bern, 3012 Bern, SwitzerlandInstitute of Pharmacology (PKI), University of Bern, 3010 Bern, SwitzerlandDepartment of Chemistry and Biochemistry, University of Bern, 3012 Bern, SwitzerlandClinic for Nuclear Medicine, University Medical Center Mainz, 55131 Mainz, GermanyGirentuximab (cG250) targets carbonic anhydrase IX (CAIX), a protein which is expressed on the surface of most renal cancer cells (RCCs). cG250 labeled with <sup>177</sup>Lu has been used in clinical trials for radioimmunotherapy (RIT) of RCCs. In this work, an extensive characterization of the immunoconjugates allowed optimization of the labeling conditions with <sup>177</sup>Lu while maintaining immunoreactivity of cG250, which was then investigated in in vitro and in vivo experiments. cG250 was conjugated with S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA(SCN)) by using incubation times between 30 and 90 min and characterized by mass spectrometry. Immunoconjugates with five to ten DOTA(SCN) molecules per cG250 molecule were obtained. Conjugates with ratios less than six DOTA(SCN)/cG250 had higher in vitro antigen affinity, both pre- and postlabeling with <sup>177</sup>Lu. Radiochemical stability increased, in the presence of sodium ascorbate, which prevents radiolysis. The immunoreactivity of the radiolabeled cG250 tested by specific binding to SK-RC-52 cells decreased when the DOTA content per conjugate increased. The in vivo tumor uptake was < 10% ID/g and independent of the total amount of protein in the range between 5 and 100 µg cG250 per animal. Low tumor uptake was found to be due to significant necrotic areas and heterogeneous CAIX expression. In addition, low vascularity indicated relatively poor accessibility of the CAIX target.https://www.mdpi.com/1424-8247/11/4/132carbonic anhydrase IXgirentuximabrenal cell carcinomas<sup>177</sup>Lu-radiopharmaceuticalsradioimmunotherapy |
| spellingShingle | Tais Basaco Stefanie Pektor Josue M. Bermudez Niurka Meneses Manfred Heller José A. Galván Kayluz F. Boligán Stefan Schürch Stephan von Gunten Andreas Türler Matthias Miederer Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo Pharmaceuticals carbonic anhydrase IX girentuximab renal cell carcinomas <sup>177</sup>Lu-radiopharmaceuticals radioimmunotherapy |
| title | Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo |
| title_full | Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo |
| title_fullStr | Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo |
| title_full_unstemmed | Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo |
| title_short | Evaluation of Radiolabeled Girentuximab In Vitro and In Vivo |
| title_sort | evaluation of radiolabeled girentuximab in vitro and in vivo |
| topic | carbonic anhydrase IX girentuximab renal cell carcinomas <sup>177</sup>Lu-radiopharmaceuticals radioimmunotherapy |
| url | https://www.mdpi.com/1424-8247/11/4/132 |
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