Phthalocyanine-peptide conjugates: receptor-targeting bifunctional agents for imaging and photodynamic therapy.
The synthesis of a series of new zinc phthalocyanine-peptide conjugates targeting the gastrin-releasing peptide (GRP) and integrin receptors is reported. Two alternative synthetic methods based on Sonogashira cross-coupling of an iodinated zinc phthalocyanine with acetylenic bombesin or arginine-glycine-aspartic acid (RGD) derivatives, either in solution or on solid phase, are presented. The water-soluble conjugates were screened for their photodynamic efficacy against several cancer cell lines expressing different levels of GRP and integrin receptors, and their intracellular localization was evaluated via confocal fluorescence microscopy. Variations in photocytotoxicity between the conjugates correlate to differences in hydrophobicity as well as receptor-mediated cell uptake. In the case of the phthalocyanine-bombesin conjugate, competition experiments confirm the involvement of the GRP receptor in both the phototherapeutic activity as well as intracellular localization. These findings warrant further in vivo studies to evaluate the potential of this conjugate as photosensitizer for photodynamic therapy (PDT) of cancers overexpressing the GRP receptor.
Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
Elena
E
Ranyuk
Nicole
N
Cauchon
Klaus
K
Klarskov
Brigitte
B
Guérin
Johan E
JE
van Lier
D000480:Alkynes / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001839:Bombesin / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology; D045744:Cell Line, Tumor; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D019886:Gastrin-Releasing Peptide / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D016023:Integrins / Q000378:metabolism; D054833:Isoindoles; D051379:Mice; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D015032:Zinc
D000480:Alkynes; D056831:Coordination Complexes; D007211:Indoles; D016023:Integrins; D054833:Isoindoles; D009842:Oligopeptides; D017319:Photosensitizing Agents; C047981:arginyl-glycyl-aspartic acid; D019886:Gastrin-Releasing Peptide; D015032:Zinc; D001839:Bombesin; C013647:phthalocyanine