Photodynamic therapy of bladder cancer cell lines.

OBJECTIVE: To determine the effect of photodynamic therapy mediated by 5-aminolevulinic acid (ALA) on a range of bladder cancer cell lines, including a squamous cancer cell line and a multi-drug resistant cell line. MATERIALS AND METHODS: Experiments were performed on cells growing in culture: the cell lines studied were the transitional cell cancer lines RT112, T24 and EJ138, the squamous cancer cell line, SCaBER, and the multi-drug resistant transitional cancer cell line, MGH-U1(R), together with its non-resistant parent line, MGH-U1. The kinetics of the ALA-mediated generation of fluorescent photosensitizer were determined using flow cytometry. Photodynamic therapy was performed by incubating cells in ALA followed by exposure to various doses of white light. RESULTS: The response of the various transitional cancer cell lines to photodynamic therapy depended on dose. The squamous cell line was relatively resistant to photodynamic therapy. There was some cross-resistance of the MGH-U1(R) cell line to photodynamic therapy, although the mechanism of cross-resistance appeared not to be necessarily a property of the drug-resistant phenotype. CONCLUSION: This study suggests that ALA-mediated photodynamic therapy may be effective in transitional cell carcinoma of the bladder. Based on these findings, this therapeutic method should be further evaluated clinically.