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Inhibition of autophagy sensitizes cancer cells to Photofrin-based photodynamic therapy
- Source :
- BMC Cancer, Vol 18, Iss 1, Pp 1-10 (2018)
- Publication Year :
- 2018
- Publisher :
- BMC, 2018.
-
Abstract
- Abstract Background Accumulating evidence suggest that autophagy plays a pivotal role in various anticancer therapies, including photodynamic therapy (PDT), acting as a pro-death or pro-survival mechanism in a context-dependent manner. Therefore, we aimed to determine the role of autophagy in Photofrin-based PDT. Methods In vitro cytotoxic/cytostatic effects of PDT were evaluated with crystal violet cell viability assay. Autophagy induction was analyzed by immunoblotting and immunofluorescence using anti-LC3 antibody. Autophagy was inhibited by shRNA-mediated ATG5 knockdown or CRISPR/Cas9-mediated ATG5 knockout. Apoptosis was assessed by flow cytometry analysis of propidium iodide and anexin V-positive cells as well as by detection of cleaved PARP and caspase 3 proteins using immunoblotting. Protein carbonylation was evaluated by the 2,4-dinitrophenylhydrazine (DNPH) method. Results Photofrin-PDT leads to robust autophagy induction in two cancer cell lines, Hela and MCF-7. shRNA-mediated knockdown of ATG5 only partially blocks autophagic response and only marginally affects the sensitivity of Hela and MCF-7 cells to PDT. ATG5 knockout in HeLa cell line utilizing CRISPR/Cas9 genome editing results in increased PDT-mediated cytotoxicity, which is accompanied by an enhanced apoptotic response and increased accumulation of carbonylated proteins. Conclusions Altogether, these observations imply that autophagy contributes to Photofrin-PDT resistance by enabling clearance of carbonylated and other damaged proteins. Therefore, autophagy inhibition may serve as a strategy to improve PDT efficacy.
Details
- Language :
- English
- ISSN :
- 14712407
- Volume :
- 18
- Issue :
- 1
- Database :
- Directory of Open Access Journals
- Journal :
- BMC Cancer
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.16867412d425487fa07cdb3436c77e42
- Document Type :
- article
- Full Text :
- https://doi.org/10.1186/s12885-018-4126-y