title: mTHPC-based photodynamic therapy induction of autophagy and apoptosis in cultured cells in relation to mitochondria and endoplasmic reticulum stress.
abstract: Photodynamic therapy (PDT), an approved anticancer treatment, is reported as a potent inducer of programmed cell death (PCD) by both apoptosis and autophagy. The present study investigated the kinetics of both autophagy and caspase activation in MCF-7 cells submitted to mTHPC-PDT upon condition of treatment promoting ER accumulation of mTHPC. Fluence-dependent immediate cytochrome c (cyt C) release followed by caspase-9 and -7 activation at 1 h post-PDT evidenced a mitochondrial oxidative stress triggered by high light doses leading to >90% of cell death. ER oxidative stress was monitored by the induction of the glucose-related protein chaperone GRP78. From 6 h post-PDT, GRP78 induction was accompanied by the conversion of LC3-I into LC3-II, the hallmark of autophagosome formation. The formation of acid vesicles evidenced by fluorescence microscopy was obvious from 22 h post-PDT. Twenty-four hours post-PDT, cyt C release decreased and caspase-9 cleavage disappeared, while the expression of cleaved caspase-7 remained significant. At the same time, the profiles of GRP78, cleaved caspase-7 and LC3-II expression were similar irrespective of light doses. In contrast to an inhibitor of caspase activation Z-VAD-FMK, the use of autophagy inhibitor, Wortmannin, impaired cytotoxicity along with an increase in caspase-7 activation. These results demonstrate a valuable contribution of autophagy to cell death in mTHPC-photosensitized MCF-7 cells.
authors.affiliation: CRAN-CNRS UMR 7039 Nancy-University, Centre Alexis Vautrin, 54511 Vandoeuvre-lès-Nancy, France. a.francois@nancy.unicancer.fr
authors.forename: Aurélie
authors.initials: A
authors.lastname: François
authors.forename: Sophie
authors.initials: S
authors.lastname: Marchal
authors.forename: François
authors.initials: F
authors.lastname: Guillemin
authors.forename: Lina
authors.initials: L
authors.lastname: Bezdetnaya
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000730:Androstadienes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress; D006801:Humans; D007700:Kinetics; D008652:Mesoporphyrins / Q000494:pharmacology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects*; D018384:Oxidative Stress; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000730:Androstadienes; D061945:Caspase Inhibitors; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D008652:Mesoporphyrins; D008869:Microtubule-Associated Proteins; D017319:Photosensitizing Agents; D047428:Protein Kinase Inhibitors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases; C072269:temoporfin; D000077191:Wortmannin