title: Synthesis and characterization of novel zinc phthalocyanines as potential photosensitizers for photodynamic therapy of cancers.
abstract: Two novel zinc phthalocyanines (Pcs): tetramethyl tetrakis-2,(3)-[(4-methyl-2-pyridyloxy)phthalocyaninato] zinc(II) (4) and (the negatively charged form) tetrakis-2,(3)-[(3-carboxylicacid-6-sulfanylpyridine)phthalocyaninato] zinc(II) (5), water soluble by virtue of their ionic substituent groups were synthesized. The spectroscopic properties of both compounds were determined and their photodynamic activities were investigated in a human tumor cell model. In aqueous media the two peripherally substituted water soluble Pcs are highly aggregated. The phototoxic activity of the two novel Pcs (Pc 4 and Pc 5; 0-20 μM) was shown to be time- and dose-dependent in human pancreatic carcinoid BON cells, leading to a reduction of tumor cells of >80% compared to the controls. The effectiveness of the treatment appeared to be attenuated by the aggregation of Pcs under aqueous conditions. Interestingly, even those cells that were not immediately killed by the photoactivated photosensitizer seemed to be affected by the Pc photodynamic activity, as a single PDT induced long-lasting effects on cell survival. Even 4 days after PDT, the number of surviving cells did not re-increase or still dropped, as compared to control cells. The underlying mechanism of this observation has to be deciphered in future investigations.
authors.affiliation: Department of Oral Biological Sciences, School of Oral Health Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. Sharon.Moeno@wits.ac.za.
authors.forename: S
authors.initials: S
authors.lastname: Moeno
authors.forename: R W M
authors.initials: RW
authors.lastname: Krause
authors.forename: E A
authors.initials: EA
authors.lastname: Ermilov
authors.forename: W
authors.initials: W
authors.lastname: Kuzyniak
authors.forename: M
authors.initials: M
authors.lastname: Höpfner
mesh_terms: D000042:Absorption; D016923:Cell Death; D045744:Cell Line, Tumor; D005453:Fluorescence; D006801:Humans; D008027:Light; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010190:Pancreatic Neoplasms / Q000188:drug therapy; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D009942:Organometallic Compounds; D017319:Photosensitizing Agents; C000591677:tetrakis-2,(3)-((3-carboxylicacid-6-sulfanylpyridine)phthalocyaninato)zinc(II); C000591676:tetramethyltetrakis-2,(3)-((4-methyl-2-pyridyloxy)phthalocyaninato)zinc(II); D014867:Water