title: Antiangiogenic photodynamic therapy (PDT) by using long-circulating liposomes modified with peptide specific to angiogenic vessels.
abstract: For the improvement of therapeutic efficacy in photodynamic therapy (PDT) by using a photosensitizer, benzoporphyrin derivative monoacid ring A (BPD-MA), we previously prepared polyethylene glycol (PEG)-modified liposomes encapsulating BPD-MA (PEG-Lip BPD-MA). PEGylation of liposomes enhanced the accumulation of BPD-MA in tumor tissue at 3 h after injection of it into Meth-A-sarcoma-bearing mice, but, unexpectedly, decreased the suitability of the drug for PDT when laser irradiation was performed at 3 h after the injection of the liposomal photosensitizer. To improve the bioavailability of PEG-Lip BPD-MA, we endowed the liposomes with active-targeting characteristics by using Ala-Pro-Arg-Pro-Gly (APRPG) pentapeptide, which had earlier been isolated as a peptide specific to angiogenic endothelial cells. APRPG-PEG-modified liposomal BPD-MA (APRPG-PEG-Lip BPD-MA) accumulated in tumor tissue similarly as PEG-Lip BPD-MA and to an approx. 4-fold higher degree than BPD-MA delivered with non-modified liposomes at 3 h after the injection of the drugs into tumor-bearing mice. On the contrary, unlike the treatment with PEG-Lip BPD-MA, APRPG-PEG-Lip BPD-MA treatment strongly suppressed tumor growth after laser irradiation at 3 h after injection. Finally, we observed vasculature damage in the dorsal air sac angiogenesis model by APRPG-PEG-Lip BPD-MA-mediated PDT. The present results suggest that antiangiogenic PDT is an efficient modality for tumor treatment and that tumor neovessel-targeted, long-circulating liposomes are a useful carrier for delivering photosensitizer to angiogenic endothelial cells.
authors.affiliation: Department of Medical Biochemistry and COE Program in the 21st Century, University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Shizuoka 422-8526, Japan.
authors.forename: Kanae
authors.initials: K
authors.lastname: Ichikawa
authors.forename: Tomoya
authors.initials: T
authors.lastname: Hikita
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Maeda
authors.forename: Sei
authors.initials: S
authors.lastname: Yonezawa
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Asai
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Namba
authors.forename: Naoto
authors.initials: N
authors.lastname: Oku
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D008081:Liposomes / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009389:Neovascularization, Pathologic / Q000188:drug therapy*; D010455:Peptides / Q000494:pharmacology*; D010778:Photochemotherapy; D011092:Polyethylene Glycols
chemical_list: D020533:Angiogenesis Inhibitors; D008081:Liposomes; D010455:Peptides; D011092:Polyethylene Glycols