ABSTRACT
Photodynamic therapy (PDT) has been approved as proper and effective kind of treatment for certain types of cancer and non-malignant diseases. We tested photodynamic effects on G361 human melanoma cells sensitized by zinc-5,10,15,20-tetrakis(4-sulphonatophenyl) porphyrine (ZnTPPS(4)), chloraluminium phtalocyanine disulfonate (ClAlPcS(2)) and 5-aminolevulinic acid (ALA). In particular, we examined the PDT efficiency depending on applied light dose (0.8; 1.7; 3.3; 6.6; 13.2; 26.4Jcm(-2)). The DNA gel electrophoresis, methylthiazol tetrazolium bromide (MTT) viability test, fluorescent microscopy using calcein AM and propidium iodide (PI) staining, and rhodamine 123 mitochondrial membrane potential assay were performed to detect and evaluate the cell death process. We also measured the time course of reactive oxygen species (ROS) production and its dependence on sensitizer concentration within continuously irradiated sensitized cells. In conclusion, these results demonstrate most significant phototoxic effect of ClAlPcS(2)-PDT in spite of significantly higher ROS production induced by ZnTPPS(4)-PDT on G361 cells. On the other hand, ALA-PDT has a minimal photoeffect and induces negligible ROS formation in G361 cells at the conditions described below.
Subject(s)
Aminolevulinic Acid/pharmacology , Indoles/pharmacology , Melanoma, Experimental/therapy , Metalloporphyrins/pharmacology , Organometallic Compounds/pharmacology , Photochemotherapy , Photosensitizing Agents/pharmacology , Cell Line, Tumor , Coloring Agents , DNA Fragmentation/drug effects , DNA Fragmentation/radiation effects , Dose-Response Relationship, Radiation , Electrophoresis, Polyacrylamide Gel , Fluorescent Dyes , Humans , Light , Membrane Potentials/drug effects , Microscopy, Fluorescence , Mitochondrial Membranes/drug effects , Propidium , Reactive Oxygen Species/metabolism , Rhodamine 123 , Tetrazolium Salts , ThiazolesABSTRACT
Several recent studies bring evidence of cell death enhancement in photodynamic compound loaded cells by ultrasonic treatment. There are a number of hypotheses suggesting the mechanism of the harmful ultrasonic effect. One of them considers a process in the activation of photosensitizers by ultrasonic energy. Because the basis of the photodynamic damaging effect on cells consists in the production of reactive oxygen species (ROS), we focused our study on whether the ultrasound can increase ROS production within cancer cells. Particularly, we studied ROS formation in ultrasound pretreated breast adenocarcinoma cells during photodynamic therapy in the presence of chloroaluminum phthalocyanine disulfonate (ClAlPcS2). Production of ROS was investigated by the molecular probe CM-H2DCFDA. Our results show that ClAlPcS2 induces higher ROS production in the ultrasound pretreated cell lines at a concentration of 100 microM and light intensity of 2 mW/cm2. We also observed a dependence of ROS production on photosensitizer concentration and light dose. These results demonstrate that the photodynamic effect on breast cancer cells can be enhanced by ultrasound pretreatment.
