Investigation of a potential scintigraphic tracer for imaging apoptosis: Radioiodinated annexin V-Kunitz protease inhibitor fusion protein
Journal
Journal of Biomedicine and Biotechnology
Journal Volume
2011
Date Issued
2011
Author(s)
Wun, T.-C.
Liao, M.-H.
Chiang, C.-C.
Yen, K.-C.
Liao, T.-Z.
Chen, M.-W.
Chi, C.-W.
Yen, T.-C.
Wey, S.-P.
Abstract
Radiolabeled annexin V (ANV) has been widely used for imaging cell apoptosis. Recently, a novel ANV-Kunitz-type protease inhibitor fusion protein, ANV-6L15, was found to be a promising probe for improved apoptosis detection based on its higher affinity to phosphatidylserine (PS) compared to native ANV. The present paper investigates the feasibility of apoptosis detection using radioiodinated ANV-6L15. Native ANV and ANV-6L15 were labeled with iodine-123 and iodine-125 using Iodogen method. The binding between the radioiodinated proteins and erythrocyte ghosts or chemical-induced apoptotic cells was examined. ANV-6L15 can be radioiodinated with high yield (40%-60%) and excellent radiochemical purity (>95%). (123)I-ANV-6L15 exhibited a higher binding ratio to erythrocyte ghosts and apoptotic cells compared to (123)I-ANV. The biodistribution of (123)I-ANV-6L15 in mice was also characterized. (123)I-ANV-6L15 was rapidly cleared from the blood. High uptake in the liver and the kidneys may limit the evaluation of apoptosis in abdominal regions. Our data suggest that radiolabeled ANV-6L15 may be a better scintigraphic tracer than native ANV for apoptosis detection.
Type
journal article