Enhancing the efficiency of 5-aminolevulinic acid-mediated photodynamic therapy using 5-fluorouracil on human melanoma cells

Background: 5-Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is an effective and noninvasive modality for treatment of several types of non-melanoma skin cancers. This in-vitro study attempted to know whether the killing effect of ALA-PDT on the human melanoma cells (Mel-Rm cell line) could be increased by the presence of 5-fluorouracil (5-FU). Methods: To evaluate the effect of ALA-PDT in combination with 5-FU on viability of human melanoma Mel-Rm cells, the cells incubated with 5-ALA and 5-FU for 3h in nontoxic concentrations, and subsequently illuminated with a 630 nm light-emitting diode array. The cells viability and cytotoxicity determined by mitochondrial activity and lactate dehydrogenase assays. Results: Combination of ALA-PDT and 5-FU (FU-ALA-PDT) showed a considerable growth inhibition according to the results of MTT assay compared to ALA-PDT. The results of LDH assay also showed a cytotoxicity effect in ALA-PDT; however, the FU-ALA-PDT showed no significantly enhancement in cytotoxicity compared to ALA-PDT using LDH assay. Conclusion: The Mel-Rm cells incubation with 5-FU before PDT enhances the efficiency of 5-Aminolevulinic acid-mediated photodynamic therapy.