Photosensitising Activity of Phthalocyanine Dyes Screened Against Tissue Culture Cells

Abstract

Abstract. A series of phthalocyanine (Pc) dyes were screened for their ability to photosensitise murine embryonic fibroblasts or fibrosarcoma cells. Cells were cultured in the presence of the dyes for 24 h. following which they were irradiated with either room light or red light and cultured for a further 72‐h period. Eleven water‐insoluble Pc (including a free‐base Pc) and 6 water‐soluble sulfonated derivatives were screened in this fashion. Free base (H2), copper (Cu), copper di‐. tri‐, tetra‐sulfonated (CuS2, CuS3. CuS4), fiuoro chromium (FCr), iron (Fe), cobalt (Co), palladium tetra‐sulfonated (PdS4). nickel (Ni) and nickel tetra‐sulfonated (NiS4)Pc dyes had no cytotoxic activity in these assays under conditions of either room‐light or red‐light exposure. Magnesium (Mg), zinc (Zn) and zirconium (Zr) Pc dyes were highly toxic to cells, producing 0% survival at 72 h, following exposure to both light sources. In contrast, chloro aluminum (C1AI). chloro aluminum sulfonated (C1A1S) and dichloro tin (Cl2Sn) Pc dyes exhibited differential phototoxicity, producing total cell death following red‐light irradiation but no or little cytotoxic effect after exposure to room light, raising the possibility that these dyes might prove useful for photo‐dynamic therapy of cancer.

Water-soluble aluminium phthalocyanine–polymer conjugates for PDT: photodynamic activities and pharmacokinetics in tumour-bearing mice

“…However, after 24 h incubation, differences in photoactivity among the three dye preparations were much less pronounced. AlClPc photoactivity is consistent with literature data (Ben-Hur and Rosenthal, 1986;Chan et al, 1987;Daziano et al, 1996;Rasch et al, 1996). However, among the phthalocyanines evaluated in our laboratory, these AlPc derivatives are not the most active on cell cultures.…”

Phthalocyanines as Photodynamic Sensitizers*

“…Conversely, paramagnetic metals such as Cu, Co, Ni, Fe, VO, FCr, Pd, intensify the intersystem crossing and shorten the lifetime of the triplet state making the dye photoinactive (Chan et al, 1987a). Metal free-PCS was inactive in sensitizing the photohemolyses of red blood cells (Sonoda et al, 1987) and had only a very weak cell killing effect in experiments with human glioblastoma in vitro (Abernathey et al, 1987) and several other tissue culture cells (Chan et al, 1987a) as well as with EMT-6 (Brasseur et al, 1987a) and C3II mammary carcinoma in mice, suggesting that a central metal is a prerequisite for a good sensitizer.…”

Photocytotoxic efficacy of sulphonated species of aluminium phthalocyanine against cell monolayers, multicellular spheroids and in vivo tumours

“…One of the major advantages of the MPc is that this group of compounds absorbs light strongly in the red region (Q band -670 nm); a region of the spectrum which permits good tissue penetration. Generally, the active MPc contain central diamagnetic metal ions, such as aluminium, gallium, tin and zinc (Brasseur et al, 1985;Ben-Hur & Rosenthal, 1986;Brasseur et al, 1987;Chan et al, 1987aChan et al, , 1988Brasseur et al, 1988;Paquette et al, 1988) while sulphonation of the benzene rings of the macrocycle leads to solubility in water which facilitates administration to animals. One such compound, AlSPc, has been shown by ourselves (Chan et al, 1986(Chan et al, , 1988 and others (Sandeman et al, 1987;Tralau et al, 1987a;Nelson et al, 1988) to be a particularly promising agent for PDT.…”