RT Journal Article
SR Electronic
T1 Carrier-Mediated Delivery Improves the Efficacy of 9-(2-Phosphonylmethoxyethyl)Adenine against Hepatitis B Virus
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 521
OP 527
VO 60
IS 3
A1 Martin K. Bijsterbosch
A1 Chunxiao Ying
A1 Remco L. A. de Vrueh
A1 Erik de Clercq
A1 Erik A. L. Biessen
A1 Johan Neyts
A1 Theo J. C. van Berkel
YR 2001
UL http://molpharm.aspetjournals.org/content/60/3/521.abstract
AB We recently synthesized a lipophilic prodrug of 9-(2-phosphonyl-methoxyethyl)adenine (PMEA), designated PMEA-LO, and incorporated it into reconstituted lactosylated high-density lipoprotein (LacNeoHDL). In a rat model, LacNeoHDL-associated PMEA-LO was internalized by the asialoglycoprotein receptor on parenchymal liver cells and converted into its active diphosphorylated metabolite. To further evaluate the therapeutic potential of the carrier-associated prodrug, we examined in this study the processing of125I-labeled PMEA-LO–loaded LacNeoHDL by HepG2 cells. Upon incubation with HepG2 cells, PMEA-LO–loaded LacNeoHDL became rapidly cell-associated. The association was saturable and of high-affinity (kd = 3.8 ± 0.4 nM). Asialofetuin, an established ligand for the asialoglycoprotein receptor, inhibited the association by >75%, which confirms the role of the asialoglycoprotein receptor. Association of the prodrug-loaded particles to HepG2 cells was coupled to degradation. Radiolabeled degradation products appeared in the culture medium with a lag phase of 2 h. Asialofetuin and chloroquine inhibited secretion of degradation products by 75 to 80%, indicating that PMEA-LO–loaded LacNeoHDL is internalized via the asialoglycoprotein receptor and lysosomally processed. The therapeutic potential of LacNeoHDL-associated PMEA-LO was studied by measuring its effects on hepatitis B virus (HBV) replication in Hep AD38 cells (HBV-transfected HepG2 cells). LacNeoHDL-associated PMEA-LO effectively inhibited HBV DNA synthesis. The EC50 value of carrier-associated PMEA-LO was 35 times lower than that of free PMEA (3.4 ± 0.4 and 120 ± 18 ng of PMEA/ml, respectively). We conclude that the present results, combined with our earlier in vivo disposition data, underscore the therapeutic potential and utility of PMEA-LO–loaded LacNeoHDL for treatment of chronic hepatitis B. The American Society for Pharmacology and Experimental Therapeutics