Binding and internalization of NGR-peptide-targeted liposomal doxorubicin (TVT-DOX) in CD13-expressing cells and its antitumor effects.
In an effort to develop new agents and molecular targets for the treatment of cancer, aspargine-glycine-arginine (NGR)-targeted liposomal doxorubicin (TVT-DOX) is being studied. The NGR peptide on the surface of liposomal doxorubicin (DOX) targets an aminopeptidase N (CD13) isoform, specific to the tumor neovasculature, making it a promising strategy. To further understand the molecular mechanisms of action, we investigated cell binding, kinetics of internalization as well as cytotoxicity of TVT-DOX in vitro. We demonstrate the specific binding of TVT-DOX to CD13-expressing endothelial [human umbilical vein endothelial cells (HUVEC) and Kaposi sarcoma-derived endothelial cells (SLK)] and tumor (fibrosarcoma, HT-1080) cells in vitro. Following binding, the drug was shown to internalize through the endosomal pathway, eventually leading to the localization of doxorubicin in cell nuclei. TVT-DOX showed selective toxicity toward CD13-expressing HUVEC, sparing the CD13-negative colon-cancer cells, HT-29. Additionally, the nontargeted counterpart of TVT-DOX, Caelyx, was less cytotoxic to the CD13-positive HUVECs demonstrating the advantages of NGR targeting in vitro. The antitumor activity of TVT-DOX was tested in nude mice bearing human prostate-cancer xenografts (PC3). A significant growth inhibition (up to 60%) of PC3 tumors in vivo was observed. Reduction of tumor vasculature following treatment with TVT-DOX was also apparent. We further compared the efficacies of TVT-DOX and free doxorubicin in the DOX-resistant colon-cancer model, HCT-116, and observed the more pronounced antitumor effects of the TVT-DOX formulation over free DOX. The potential utility of TVT-DOX in a variety of vascularized solid tumors is promising.
Garde
Seema V
SV
Ambrilia Biopharma Inc., Chemin Du Golf, Verdun, Quebec, Canada. sgarde@ambrilia.com
Forté
André J
AJ
Ge
Michael
M
Lepekhin
Eugene A
EA
Panchal
Chandra J
CJ
Rabbani
Shafaat A
SA
Wu
Jinzi J
JJ
D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D001692:Biological Transport; D018826:CD13 Antigens / Q000378:metabolism; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms; D004317:Doxorubicin / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008081:Liposomes; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009842:Oligopeptides / Q000378:metabolism*; D011471:Prostatic Neoplasms; D011485:Protein Binding
D000970:Antineoplastic Agents; D008081:Liposomes; C526428:NGR peptide; D009842:Oligopeptides; D004317:Doxorubicin; D018826:CD13 Antigens