Abstract | INTRODUCTION: METHODS: mAb 376.96 was conjugated to the chelate 2-(4-isothiocyanotobenzyl)-1,4,7,10-tetraaza-1,4,7,10-tetra-(2-carbamoylmethyl)-cyclododecane (TCMC) and radiolabeled with 212Pb, a source of α-particles. In vitro Scatchard assays determined the specific binding of 212Pb-376.96 to adherent differentiated or non-adherent CIC-enriched ES-2 and A2780cp20 ovarian cancer cells. Adherent ovarian cancer cells and non-adherent CIC-enriched tumorspheres treated in vitro with 212Pb-376.96 or the irrelevant isotype-matched 212Pb-F3-C25 were assessed for clonogenic survival. Mice bearing i.p. ES-2 or A2780cp20 xenografts were injected i.p. with 0.17-0.70MBq 212Pb-376.96 or 212Pb-F3-C25 and were used for in vivo imaging, ex vivo biodistribution, and therapeutic survival studies. RESULTS: 212Pb-376.96 was obtained in high yield and purity (>98%); Kd values ranged from 10.6-26.6nM for ovarian cancer cells, with 104-105 binding sites/cell. 212Pb-376.96 inhibited the clonogenic survival of ovarian cancer cells up to 40 times more effectively than isotype-matched control 212Pb-F3-C25; combining 212Pb-376.96 with carboplatin significantly decreased clonogenic survival compared to either agent alone. In vivo imaging and biodistribution analysis 24h after i.p. injection of 212Pb-376.96 showed high peritoneal retention and tumor tissue accumulation (28.7% ID/g in ES-2 ascites, 73.1% ID/g in A2780cp20 tumors); normal tissues showed lower and comparable uptake for 212Pb-376.96 and 212Pb-F3-C25. Tumor-bearing mice treated with 212Pb-376.96 alone or combined with carboplatin survived 2-3 times longer than mice treated with 212Pb-F3-C25 or non-treated controls. CONCLUSION: These results support additional RIT studies with 212Pb-376.96 for future evaluation in patients with ovarian cancer.
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Authors | Benjamin B Kasten, Rebecca C Arend, Ashwini A Katre, Harrison Kim, Jinda Fan, Soldano Ferrone, Kurt R Zinn, Donald J Buchsbaum |
Journal | Nuclear medicine and biology
(Nucl Med Biol)
Vol. 47
Pg. 23-30
(Apr 2017)
ISSN: 1872-9614 [Electronic] United States |
PMID | 28104527
(Publication Type: Journal Article)
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Copyright | Copyright © 2017 Elsevier Inc. All rights reserved. |
Chemical References |
- Antibodies, Monoclonal
- B7 Antigens
- CD276 protein, human
- Epitopes
- Lead Radioisotopes
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Topics |
- Animals
- Antibodies, Monoclonal
(immunology, therapeutic use)
- B7 Antigens
(immunology)
- Cell Differentiation
- Cell Line, Tumor
- Cell Survival
- Cell Transformation, Neoplastic
- Epitopes
(immunology)
- Female
- Humans
- Lead Radioisotopes
(therapeutic use)
- Mice
- Ovarian Neoplasms
(pathology, radiotherapy)
- Radioimmunotherapy
(methods)
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