PHTHALOCYANINE PHOTOSENSITIZATION OF MAMMALIAN CELLS: BIOCHEMICAL and ULTRASTRUCTURAL EFFECTS

Abstract

The incorporation of thymidine, uridine and leucine into DNA, RNA and proteins, respectively, was measured in log‐phase Chinese hamster cells photosensitized by chloroaluminum phthalo‐cyanine tetrasulfonate (A1PCS). Post‐treatment synthesis of all macromolecules was inhibited. The inhibition became progressively more pronounced with time, reaching a maximum at ca. 3 h after treatment. The differences between relative sensitivity of protein, RNA and DNA syntheses to A1PCS photosensitization, were not statistically significant. Some of the observed inhibition was due to a reduced uptake of the labeled precursors from the growth medium. Energy metabolism, as reflected by glucose oxidation, was sensitive to A1PCS plus light. Inhibition of glucose oxidation was evident immediately after treatment, and became more pronounced with time. Following a sublethal light fluence, maximum inhibition was observed at 3 h and there was a gradual recovery at later times. Inhibition of glucose oxidation was about two fold higher in plateau‐phase compared to log‐phase cells. The former were also twice as sensitive with respect to cell killing. These results suggest that inhibition of glucose oxidation induced by mitochondrial damage as seen in human lymphocytes, may be a primary cause for AlPCS‐photosensitized cell killing.

Photodynamic laser therapy of carcinomas — effects of five different photosensitizers in the colony-forming assay

“…"Sulfo-Aluminium-Phthalocyanin" was shown to be an effective photosensitizing agent [1]. Indigocarmine, "IR 132" and "Sulfo-Phthalocyanin" were shown to be relatively ineffective agents; a finding which might have been predicted by their chemical structure.…”

“…Photodynamic therapy involves the treatment of malignancies by using the interaction between a photosensitizer and laser radiation at a defined wavelength. The result of such an interaction is a liberation of oxygen radicals leading to photooxidation of the biological target and a so-called photodynamic cytotoxicity [1][2][3]5].…”

Size-dependent resistance of human tumour spheroids to photodynamic treatment

“…It has been reported that logand plateau-phase NHIK cells are equally sensitive to HPD plus light (Christensen et al, 1984) and that plateau-phase V79 cells are more sensitive than those in log-phase to chloroaluminium phthalocyanine (Ben-Hur et al, 1987). Although these studies involved different photosensitisers, the results may parallel the situation seen for sensitivity to sparsely ionising radiation where some cell lines are equally sensitive across the growth phases, others are more sensitive in plateau-phase and others more sensitive in log-phase (Hahn & Little, 1972).…”

Photodynamic Effects of Sulfonated Aluminum Chlorophthalocyanine in Human Urinary Bladder Carcinoma Cells in vitro

“…Destruction of the mitochondria resulting from PDT with AlCISPc has been reported by Ben-Hur et al [1] and Richelli et al [15]. Damage to mitochondria has also been associated with the photosensitizers photosan [16], rhodamine [17] and doxycycline [18].…”

“…To date, dyes used in PDT have been mostly hematoporphyrin derivatives (HPD) [1][2][3][4][5]. In clinical trials, however, these substances failed to fulfil the above-mentioned requirements.…”