Journal
AUTOPHAGY
Volume 7, Issue 9, Pages 979-984Publisher
TAYLOR & FRANCIS INC
DOI: 10.4161/auto.7.9.15865
Keywords
apoptosis; autophagy; benzoporphyrin; photodynamic
Categories
Funding
- National Cancer Institute [CA 23378]
- NIH [GM-058905-11, T32-CA009531]
Ask authors/readers for more resources
Photodynamic therapy (PDT) is a process that can induce apoptosis, autophagy or both depending on the cell phenotype. Apoptosis is a pathway to cell death while autophagy can protect from photokilling or act as a death pathway. In a previous study, we reported a cytoprotective effect of autophagy in murine leukemia cell lines where both autophagy and apoptosis occur within minutes after irradiation of photosensitized cells. In this study, we examined the effects of mitochondrial photodamage catalyzed by low (<= 1 mu M) concentrations of the photosensitizing agent termed benzoporphyrin derivative (BPD, Verteporfin) on murine hepatoma 1c1c7 cells. Apoptosis was not observed until several hours after irradiation of photosensitized cells. Autophagy was clearly cytoprotective since PDT efficacy was significantly enhanced in a knockdown sub-line (KD) in which the level of a critical autophagy protein (Atg7) was markedly reduced. This result indicates that autophagy can protect from phototoxicity even when apoptosis is substantially delayed. Much higher concentrations (>= 10 mu M) of BPD had previously been shown to inhibit autophagosome formation. Phototoxicity studies performed with 10 mu M BPD and a proportionally reduced light dose were consistent with the absence of an autophagic process in wild-type (WT) cells under these conditions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available