Attempts to treat malignant melanoma by photodynamic therapy using bacteriopheophorbide ester as the sensitizer

摘要

Quantitative data are presented on uptake and phototoxicity of the photosensitizing drug, 13$+2$/ hydroxy bacteriopheophorbide a methyl ester, in three cell lines of melanotic (SkMel 25) and amelanotic (A375, Melur SP 18) melanoma. A375 is the most sensitive cell easily killed by irradiation with a laser diode at 775 nm by 2 J/cm$+2$/. The Melur SP 18 cell line needs 5 J/cm$+2$/ for the same effect. In both cases the decay of overliving cells obeys apparently the simple exponential law. In the melanotic SkMel 25 an overshoting plateau at low energy fluence was observed signalizing a metastatic potency induced by PDT. This is documented by a series of photographs. In principle, photosensitizing drugs with absorption maxima in the far red region are suitable to treat malignant melanoma with high efficiency. A method has to be developed to overcome PDT stimulation at low energy densities in melanotic melanoma.