Aminolevulinic acid for photodynamic therapy of bladder carcinoma cells.

A new concept in photosensitizing tumor cells is photosensitizer synthesis in situ. Aminolevulinic acid (ALA) is a precursor of protoporphyrin IX (PP IX), a potent photosensitizer. The goal of our study was to examine dark toxicity, phototoxic potential, metabolism of ALA and morphological alterations in Waf bladder cancer cells. Dark toxicity of Waf cells was observed after incubation with ALA, beginning at a concentration of 15 mM. Photodynamic treatment with ALA at concentrations of 1, 5 and 10 mM showed a drug- and light-dose-dependent cell survival rate in comparison to a control group. Two incubation times of 3.5 and 5.5 h were compared for cell survival. After a longer incubation time of 5.5 h, cell survival was decreased in all experiments; this is consistent with our extraction data where higher fluorescence was found after 5.5 than after 3.5 h. The results show that ALA-induced photosensitization has a high potential for photodynamic therapy (PDT) of superficial bladder carcinoma.