Binding and photodynamic action of the cationic zinc phthalocyanines with different types of DNA toward understanding of their cancer therapy activity

Two cationic zinc phthalocyanines have been tested for their interactions with several DNA secondary structures. Despite different aggregation properties, both phthalocyanines bind to DNA in monomeric forms. The strong photodynamic activity of phthalocyanines was demonstrated by in vitro experiments and correlate well with high singlet oxygen yields determined experimentally with 1,3-diphenylisobenzofurane. Both phthalocyanines accumulate in the cell cytoplasm prior to radiation; however, only the octacationic photosensitizer was observed in the cell nuclei after irradiation. Two zinc phthalocyanines useful for the photodynamic therapy of cancer were tested for their interactions with different DNA secondary structures. Both phthalocyanines bind to DNA as monomers, have strong anti-cancer activity and accumulate in the cytoplasm pre-irradiation; however only the octacationic photosensitizer was found in nuclei after irradiation. [Display omitted] •Photodynamic therapy of cancer•Cationic zinc phthalocyanines•DNA binding•Anti-cancer activity