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Generation and Screening of Monoclonal Antibodies for ImmunoPET Imaging of IGF1R in Prostate Cancer
Journal article   Open access   Peer reviewed

Generation and Screening of Monoclonal Antibodies for ImmunoPET Imaging of IGF1R in Prostate Cancer

Hao Hong, Tapas R. Nayak, Sixiang Shi, Stephen A. Graves, Brianne C. Fliss, Todd E. Barnhart and Weibo Cai
Molecular pharmaceutics, Vol.11(10), pp.3624-3630
10/06/2014
DOI: 10.1021/mp5003637
PMCID: PMC4186682
PMID: 25157758
url
https://doi.org/10.1021/mp5003637View
Published (Version of record) Open Access

Abstract

Insulin-like growth factor I receptor (IGF1R) plays an important role in proliferation, apoptosis, angiogenesis, and tumor invasion. The expression level of IGF1R is related to resistance to several targeted therapies. The goal of this study was to develop an immunoPET tracer for imaging of IGF1R in prostate cancer. Murine antibodies against human IGFIR were generated in BALB/c mice, which were screened in IGF1R-positive MCF-7 cells using flow cytometry as well as biodistribution studies with multiple Cu-64-labeled antibody clones. The antibody production method we adopted could readily produce milligram quantities of anti-IGF1R antibodies for in vivo studies. One antibody clone (1A2G11) with the highest affinity for IGFIR was selected and conjugated to NOTA for Cu-64-labeling. NOTA-1A2G11 maintained IGFIR specificity/avidity based on flow cytometry. Cu-64-labeling was achieved with good yield (>50%) and high specific activity (>1 Ci/mu mol). Serial PET imaging revealed that uptake of Cu-64-NOTA-1A2G11 was 2.8 +/- 0.7, 10.2 +/- 2.6, and 9.6 +/- 1.7 %ID/g in IGF1R-positive DU-145 tumors at 4, 24, and 48 h postinjection, respectively (n = 3), significantly higher than that in IGF1R-negative LNCaP tumors (<3 %ID/g at each time point) except at 4 h postinjection. Histology studies showed strong correlations between IGFIR expression level in the prostate cancer tumor tissues and tumor uptake of Cu-64-NOTA-1A2G11. Prominent, persistent, and IGFIR-specific uptake of Cu-64-NOTA-1A2G11 in IGF1R-positive prostate tumors holds strong potential for future cancer diagnosis, prognosis, and therapy using this antibody.
Life Sciences & Biomedicine Medicine, Research & Experimental Pharmacology & Pharmacy Research & Experimental Medicine Science & Technology

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