Subcellular photodynamic action sites of sulfonated aluminum phthalocyanines in a human melanoma cell line

By means of scanning and transmission electron microscopy the subcellular target sites of photodynamic therapy (PDT) with derivatives of sulfonated aluminum phthalocyanine (AlPcS1, AlPcS2, AlPcS3, and AlPcS4) were studied in a human melanoma LOX cell line. It was found that PDT with AlPcS1 or AlPcS2 damaged mainly the biomembraneous system of the cells, such as cytoplasmic membrane, mitochondria, endoplasmic reticulum, etc., while AlPcS3- or AlPcS4- induced PDT largely destroyed the lysosomes. However, none of the AlPcSns led to nuclear damage at an early stage after PDT. The subcellular photodynamic targets of the derivatives of AlPcSn are related to the subcellular localization pattern of the dye in the LOX cells.