Abstract
Cultured cells were exposed to each of 8 polycyclic hydrocarbons, and then illuminated with white light from a tungsten lamp. Carcinogenic hydrocarbons, benzo(a)pyrene, dimethylbenzacridine, methylcholanthrene, dimethylbenzanthracene, and benz(a)anthracene, were found to be much stronger in photosensitizing activity than noncarcinogenic ones, anthracene, pyrene, and acridine. Among the former compounds, benzopyrene is the strongest and benzanthracene the weakest. As far as the present experimental system is concerned, a clear positive association between photodynamic activity and carcinogenicity was found.
The cell-uptake of benzopyrene occurred in as fast as 1 second of incubation. When cells were illuminated, lysosomal staining with neutral red became markdely reduced and equivocal. Such alteration in lysosomal staining took place prior to the occurrence Table 2. Absorption spectra of polycyclic compounds used in the present experiment of any other detectable abnormalities. The photodynamic effect produced by the combined use of a photosensitizing substance and light is mainly, if not exclusively, due to the cell autolysis by the hydrolytic enzymes which were released from lysosomes as a result of photodynamic damage of their membrane.
