Photodynamic therapy enhances skin cancer chemotherapy effects through autophagy regulation.

Non-melanotic cutaneous cancers and melanoma are the main common type skin cancers worldwide. Despite many therapeutic options, therapeutic efficacy is not satisfied in all patients with advanced skin cancers, especially in melanoma. Photodynamic therapy (PDT) is a technology for skin disease treatment because of its high effectiveness, has no drug resistance and is easy to use compared with traditional therapy. Our previous study explored that autophagy plays an important role in the formation and development of SCC. But there was no evidence about the association between PDT with autophagy in skin cancers and the mechanism is also still unclear. In the study, we want to explore the effects of 5-aminolevulinic acid-PDT (ALA-PDT) on the skin cancers through autophagy regulation. The result showed that autophagy was regulated by ALA-PDT combined with or without 3-Methyladenine (3-MA) or 5-Fluoracil (5-FU), the proliferation of skin cancer cells A431 and A375 were suppressed while the apoptosis were induced by ALA-PDT and the effects can be enhanced by 3-MA or 5-FU pretreated. The results suggest that autophagy regulation may be a key point of ALA-PDT therapy; ALA-PDT combined with the chemotherapy of 3-FU or 5-FU may be a new strategy for treatment of skin cancers including non-melanotic cutaneous cancers or melanoma.