Efficacy of 5-aminolevulinic acid-mediated photodynamic therapy in a mouse model of esophageal cancer

5-Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is a minimally invasive therapeutic modality used in the management of various cancers, but to a lesser extent for esophageal cancer (EC). The current study investigated the antitumor effects of ALA-PDT. Human EC cells were treated with ALA, after which ALA-induced fluorescence was examined under a fluorescence microscope. The cytotoxic effects of ALA-PDT were assessed using three types of LEDs (blue, green and red) in vitro and in vivo. Subcutaneous tumor model mice was constructed with KYSE150 cells. ALA-PDT was performed once a week for 4 weeks and tumor weights were measured. A popliteal lymph node (PLN) metastasis murine model was generated using KYSE150 cells. KYSE150 cells were inoculated into the left footpad of nude mice. ALA-PDT was performed on the footpad once a week for 4 weeks. PLNs were then removed 3 weeks after the last treatment. The lymph nodes were evaluated by hematoxylin and eosin staining. Red fluorescence of protoporphyrin IX (PpIX) was observed in all EC cell lines. ALA-PDT using LEDs exerted significant antitumor effects in vitro and in vivo. The antitumor effects of ALA-PDT with blue LED were the strongest, followed by green and red LEDs. The number of metastasized PLNs was significantly smaller in the ALA-PDT group (0%) than in the control group (37.5%). The present results indicated that ALA-PDT is effective for EC.