PDT of rat mammary adenocarcinoma in vitro and in a rat dorsal skin flap window chamber using Photofrin and chloroaluminum sulfonated phthalocyanine

Photodynamic therapy has been shown to directly kill cancer cells in vitro. PDT can also kill cancer tumors in vivo, although in such a case the tumorcidal effect may be a result of several mechanisms rather than direct cancer cell kill alone. For example, PDT usually causes an inhibition in blood flow in the treatment volume and it is conceivable that such an effect might compromise the tumor. In investigating the behavior and mechanisms of PDT in vitro and in vivo, we performed PDT on a rat mammary adenocarcinoma (MTF7) both in tissue culture and in an animal model. The animal experiments were done using a rat dorsal skin flap window chamber in which a solid tumor was grown. The window chamber model allowed us to observe, over a period of weeks, the growth of the tumor and the effect of PDT on the tumor and vasculature. We utilized two different photosensitizing dyes in this study- Photofrin and chloroaluminum sulfonated phthalocyanine. In order to compare the tumorcidal efficacy of the photosensitizers in vivo and in-vitro, we quantitated the photosensitizer present in the cancer cells by measuring their fluorescence.