Asialoglycoprotein receptor targeted micelles containing carborane clusters for effective boron neutron capture therapy of hepatocellular carcinoma

Abstract

The asialoglycoprotein receptor (ASGP-R) is viewed as an ideal target for hepatocyte-specific delivery. And the galactose residue is a promising ASGP-R ligand because of its high receptor affinity. Herein, a novel polymer based on PEGylated galactose was developed to achieve boron neutron capture therapy (BNCT) for active targeting hepatocellular carcinoma (HCC) by loading carborane clusters. Notably, the polymer could self-assemble into micelles with an average diameter of 135 nm under physiological conditions. The micelle had the high selectivity and low cytotoxicity to HepG2 cells (IC50 >1000 μM). Kinetically, the micelle had the higher uptake in HepG2 cells than the positive control group sodium borocaptate (BSH) in vitro. After the HepG2 cells were treated with the micelle, the cytoskeleton was changed and the migration ability was weakened during BNCT. Apoptosis was remarkably induced by breaking of DNA double strands of cancer cells. In addition, the concentration of 10B in the tumor was 4.5 times higher than that of the BSH group at 4 h after the micelle administration in the tumor-bearing mice. The tumor/blood ratio of 10B concentration reached over 25 at 24 h after micelle injection. In the normal mice, the micelles were mainly distributed among the liver and kidney tissues and could be effectively eliminated from the body within 24 h. No systemic toxicity was observed after administration. Thus, the carborane-containing PEGylated galactose micelles with ASGP-R targeting can be used as a promising therapeutic vector for effective boron neutron capture therapy of hepatocellular carcinoma.