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

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.

Comparative Evaluation of Novel 177Lu-Labeled PNA Probes for Affibody-Mediated PNA-Based Pretargeting

“…In this case, the renal uptake exceeded tumor uptake by 10–20 fold [ 3 ]. Common methods applied for the reduction of renal uptake of radiolabeled proteins and peptides have turned out to be inefficient for affibody molecules [ 10 , 11 ].…”

Investigation of a Pharmacological Approach for Reduction of Renal Uptake of Radiolabeled ADAPT Scaffold Protein

“…However, its potential utility is limited by toxicity [ 46 ]. The effect of maleate on reduction of kidney uptake was more pronounced for ADAPTs than for affibody molecules or DARPins [ 33 , 34 ].…”

“…injection of 50–60 mmol/kg of fructose reduced the kidney uptake of radiolabeled affibody molecules and DARPins by ca. 50% [ 33 , 34 ]. As these doses are rather high and are close to the median lethal dose (LD 50 83 mmol/kg), we also included a lower dose of fructose (20 mmol/kg) in the study, however, no effect on reabsorption of [ 99m Tc]Tc(CO) 3 -ADAPT6 in kidneys was observed at a low dose.…”

“…Autoradiography of kidneys was performed as described previously [ 34 ]. The kidneys were embedded in the frozen section medium (Richard-Allan Scientific Neg-50, Thermo Fisher Scientific, Kalamazoo, MI, USA), frozen at −80 °C, cut in serial sections (30 μm thick) using a cryomicrotome (CryoStar NX70, Thermo Fisher Scientific, Runcorn, UK), and thaw-mounted on glass slides.…”

“…We have recently studied the effect of several pharmacological agents on the renal uptake of radiolabeled DARPins [ 33 ] and affibody molecules [ 34 ]. In the present study, we continue to investigate the effect of several compounds (fructose, sodium maleate, colchicine, mannitol), drugs (probenecid, furosemide) and agents used in clinics (gelofusine, lysine) for prevention of kidney uptake of another class of ESPs, ADAPTs.…”