Pyridine-containing water-soluble silicon (iv) phthalocyanines: Evaluation of photochemical properties, DNA damage, and photodynamic therapy potential

Abstract

In this study, the potential of water-soluble silicon(IV) phthalocyanine compounds bearing pyridine side groups (3PY-7a-SiQ and 3PY-8a-SiQ) as suitable photodynamic therapy (PDT) agents for breast cancer treatment was investigated. For this purpose, the photochemical properties of the compounds were first evaluated, including their aggregation behavior, singlet oxygen quantum yields, and photodegradation quantum yields. The singlet oxygen quantum yields were calculated as 'Delta = 0.181 for 3PY-7a-SiQ and 'Delta = 0.168 for 3PY-8a-SiQ. Aggregation studies revealed no evidence of aggregation for either compound. The photodegradation quantum yields were determined to be 'd = 0.64 & times; 10-5 for 3PY-7a-SiQ and 'd = 1.28 & times; 10-5 for 3PY-8a-SiQ. The hydrolytic damage, photodamage, and oxidative damage activities of the compounds were also assessed by agarose gel electrophoresis. At their highest concentrations, both compounds demonstrated significant oxidative photodamage activity following 60 min of white light irradiation. Finally, the in vitro cytotoxic and phototoxic effects of 3PY-7a-SiQ and 3PY-8a-SiQ were investigated on the MCF-7 breast cancer cell line and the non-tumorigenic MCF-10A mammary epithelial cell line using the MTT assay.