Selective photodynamic therapy induced by preirradiation of galactopyranosyl Zn(II) phthalocyanines with UV and red lights

Abstract

The challenging task in the photodynamic therapy is the optimization of the procedure in a way to reach maximal selectivity of the phototoxic effect to tumor vs. non-neoplastic cells. The present study explores the impact of the light exposure with harmless UV 365 nm and low intensity visible red 637 nm light during incubation period on the uptake, primary localization, re-localization and photocytotoxic effect of tetra-galactopyranosyl substituted Zn ( II ) phthalocyanines. The studies were carried out on cancer cells (MDA-MB-231) and on non-tumorigenic cells (Balb/c 3T3, clone 31). The experimentals suggested that in addition to the favorable chemical structure of the applied amphiphilic protected galactose Zn ( II ) phthalocyanines, the pretreatment with UV 365 nm and visible red 637 nm light applied prior therapeutic light, lead to selective phototoxic effects on tumor cells.