The effect of psoralen plus ultraviolet A in vitro in HUT-78 enhances by 5-aminolevulinic acid

BACKGROUND: Sezary syndrome and mycosis fungoides are forms of cutaneous T-cell lymphoma, and in the early stage of these diseases psoralen plus ultraviolet A (PUVA) is one of the treatments of choice. Photodynamic therapy using 5-aminolevulinic acid (ALA-PDT) is an effective, non-invasive, and safe treatment for most superficial skin cancers. In order to obtain greater efficacy of PUVA, we investigated the synergistic anti-tumor effects of ALA-PDT and PUVA using 8-methoxypsoralen (8-MOP) and a UVA lamp. METHODS: The in vitro effects of PUVA and ALA-PDT and their combination in HUT-78 cell line from human SS were determined by MTT assay. RESULTS: In our results, cell proliferation compared with controls was inhibited to 53.2% with UVA alone, 52.3% with 1 microM 8-MOP, 43.8% with 100 microM ALA, and 19.2% with combined 8-MOP and ALA. CONCLUSION: Combined use of ALA and PUVA using 8-MOP and UVA lamps, which are widespread in Japan, had a strong anti-tumor effect in vitro. Combined treatment with ALA-PDT and PUVA using a UVA lamp appears to have a strong treatment effect.