Abstract
1176
Objectives Asialoglycoprotein receptor (ASGPR) has been reported as one of the most important hepatocellular carcinoma biomarkers. We determined lactosamine density-dependent targeting potential to ASGPR in vitro and in vivo models.
Methods Human serum albumin (HSA) was conjugated with various lactosamine residues (Ln-HSA; L8-, L26-, L56-HSA) and the selected FITC-labeled L56-HSA was observed by confocal microscopy. DOTA-conjugated Ln-HSA was radiolabeled with 64CuCl2 in NaOAc (0.1 N, pH 6.0) at 37 °C for 1 h, which was purified using a PD-10. Labeling efficiencies of 64Cu-Ln-HSA were checked by ITLC. Uptake test of 64Cu-Ln-HSA was performed in ASGPR positive Hep3B and HepG2 hepatoma cell lines and negative HT29 colon carcinoma cell lines. 50ug (200 uCi/mouse) 64Cu-Ln-HSA was injected to nude mice having Hep3B, HepG2 and HT29 tumors and images were obtained using an animal PET/CT machine.
Results FITC-L56-HSA was detected in ASGPR positive hepatoma cells (Hep3B and HepG2), but not detected in negative cells (HT29). Labeling efficiency of 64Cu-Ln-HSA was over 95% and in vitro uptake test using 64Cu-Ln-HSA showed its specificity in ASGPR positive hepatoma cells. In vitro cell study and PET/CT showed that 64Cu-HSA with many lactosamine residues were accumulated more than other conjugates in ASGPR positive cells and xenograft tumors.
Conclusions Lactosaminated HSA enhanced the targeting ability to ASGPR positive cells by addition of lactosamine residues on the surface of HSA. We propose 64Cu-latosaminated HSA as a promising probe for ASGPR specific imaging.