title: Inhibitive effects of photofrin on cellular autophagy.
abstract: Depending on the circumstances, autophagy can be either a protective or damaging cellular process. The role of autophagy in photodynamic therapy (PDT), a photo-chemotherapy that utilizes light to activate a photosensitizer drug to achieve localized cellular damage, has been explored in recent years. It has been reported that autophagy in PDT is significantly influenced by the treatment protocol. In this work, the role of Photofrin, a well-established clinical photosensitizer, in regulating cellular autophagy was investigated. The effects of Photofrin on cellular autophagy induced by conventional starvation or rapamycin techniques were studied. By fluorescence imaging, Western blotting and cell viability assays, it was found that Photofrin can effectively inhibit cellular autophagy induced by starvation or rapamycin. This autophagy blocking is independent of the photosensitizing property of the drug. With Baf-A1, a well-established agent that inhibits autophagosome from fusing with lysosome, we also found that, the observed phenomenon is not due to accelerated degradation of existing autophagosomes, thus proving that the drug Photofrin alone, without light excitation, can truly block autophagy.
authors.affiliation: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China.
authors.forename: Shiming
authors.initials: S
authors.lastname: Luo
authors.forename: Da
authors.initials: D
authors.lastname: Xing
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Wei
authors.forename: Qun
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D001692:Biological Transport / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003683:Dehydroascorbic Acid / Q000494:pharmacology; D017323:Dihematoporphyrin Ether / Q000494:pharmacology*; D006801:Humans; D018942:Macrolides / Q000494:pharmacology; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D010588:Phagosomes / Q000187:drug effects / Q000378:metabolism; D010778:Photochemotherapy; D051381:Rats; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism
chemical_list: D003683:Dehydroascorbic Acid; D017323:Dihematoporphyrin Ether; D018942:Macrolides; D008869:Microtubule-Associated Proteins; C526109:Anxa3 protein, rat; C040929:bafilomycin A1