Influence of Several Compounds and Drugs on the Renal Uptake of Radiolabeled Affibody Molecules.

Anzhelika Vorobyeva,Mohamed Altai,Javad Garousi

doi:10.3390/molecules25112673

Abstract

Affibody molecules are the most studied class of engineered scaffold proteins (ESPs) in radionuclide molecular imaging. Attempts to use affibody molecules directly labelled with radiometals for targeted radionuclide therapy were hampered by the high uptake and retention of radioactivity in kidneys. Several promising strategies have been implemented to circumvent this problem. Here, we investigated whether a pharmacological approach targeting different components of the reabsorption system could be used to lower the uptake of [99mTc]Tc-ZHER:2395 affibody molecule in kidneys. Pre-injection of probenecid, furosemide, mannitol or colchicine had no influence on activity uptake in kidneys compared to the control group. Mice pre-injected with maleate and fructose had 33% and 51% reduction in the kidney-associated activity, respectively, compared to the control group. Autoradiography images showed that the accumulation of activity after [99mTc]Tc-ZHER2:2395 injection was in the renal cortex and that both maleate and fructose could significantly reduce it. Results from this study demonstrate that pharmacological intervention with maleate and fructose was effective in reducing the kidney uptake of affibody molecules. A presumable mechanism is the disruption of ATP-mediated cellular uptake and endocytosis processes of affibody molecules by tubular cells.

Highlights

Advances in protein engineering such as molecular display techniques made it possible to generate alternatives to monoclonal antibodies
Radiolabelling of ZHER2:2395 -C affibody molecule with [99m Tc]Tc was performed in 96.5 ± 1.5%
engineered scaffold-based affinity proteins (ESPs) and protein-based targeting agents below 60 kDa are readily reabsorbed in the renal tubular cells after glomerular filtration

Summary

Introduction

Advances in protein engineering such as molecular display techniques made it possible to generate alternatives to monoclonal antibodies (mAbs). Affibody molecules have been studied the most for radionuclide-based molecular imaging [3]. 20-fold smaller than the size of intact mAbs. Affibody molecules binding with high affinity to several clinically relevant cancer-associated molecular targets (HER2, EGFR, HER3, IGF-1R, PDGFRβ and CAIX) have been developed [4,5]. In molecular imaging, radiolabelled affibody molecules proved to be advantageous in comparison with mAbs enabling higher sensitivity and specificity [5]. Due to their small size, affibody molecules accumulate rapidly in tumours, undergo rapid washout from non-targeted tissues, and have a short residence time in the circulation. It was shown in preclinical studies that affibody molecules provided at least

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