Skip Navigation LinksHome > September 2013 - Volume 34 - Issue 9 > 177Lu-labeled RGD-BBN heterodimeric peptide for targeting pr...
Nuclear Medicine Communications:
doi: 10.1097/MNM.0b013e328362d2b6
Original Articles

177Lu-labeled RGD-BBN heterodimeric peptide for targeting prostate carcinoma

Jiang, Leia,b; Miao, Zhengb; Liu, Hongguangb; Ren, Gangb; Bao, Andec; Cutler, Cathy S.d; Shi, Hongchenga; Cheng, Zhenb

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Abstract

Introduction: Radiolabeled Arg-Gly-Asp (RGD) and bombesin (BBN) heterodimers have been investigated for dual targeting of tumor integrin αvβ3 receptors and gastrin-releasing peptide receptors. The goal of this study was to evaluate the potential use of a 177Lu-labeled RGD-BBN heterodimer for targeted prostate cancer therapy.

Materials and methods: A 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-conjugated RGD-BBN peptide (DO3A-RGD-BBN) was radiolabeled with 177Lu and purified by high-performance liquid chromatography. The in-vivo biodistribution study of 177Lu-DO3A-RGD-BBN was carried out in mice bearing human prostate cancer PC3 xenografts. The receptor-targeting specificity of the radiolabeled peptide was assayed by injecting the tracer with the unlabeled RGD-BBN peptide. Radiation absorbed doses in adult male patients, based on biodistribution data from mice, were also calculated.

Results: DO3A-RGD-BBN peptides were successfully labeled with 177Lu, and high radiochemical purity (>95%) could be achieved after high-performance liquid chromatography purification. In human PC3 xenograft-bearing mice, the tumor accumulation of 177Lu-DO3A-RGD-BBN was 5.88±1.12, 2.77±0.30, 2.04±0.19, and 1.18±0.19%ID/g at 0.5, 2, 24, and 48 h, respectively. With rapid clearance from normal tissues, the radiolabeled probe displayed high tumor-to-blood and tumor-to-muscle ratios. On calculating the radiation absorbed doses for 177Lu-DO3A-RGD-BBN, we found that the prostate tumor and the pancreas were the organs receiving the highest radiation absorbed doses.

Conclusion: Dual integrin αvβ3 and GPRP-targeted agent 177Lu-DO3A-RGD-BBN shows excellent prostate cancer-targeting ability, and it is worthy of further evaluation for prostate cancer-targeted therapy.

© 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

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