title: Inhibition of ERK attenuates autophagy and potentiates tumour necrosis factor-alpha-induced cell death in MCF-7 cells.
abstract: The role of autophagy in cell death is under considerable debate. The process of autophagy has been shown to lead to either cell survival or cell death depending on cell type and stimulus. In the present study, we determined the contribution of ERK1/2 signalling to autophagy and cell death induced by tumour necrosis factor-alpha (TNF) in MCF-7 breast cancer cells. Treatment of MCF-7 cells with TNF caused a time-dependent increase in ERK1/2 activity. There was an induction of autophagy and cleavage of caspase-7, -8, -9 and PARP. Pharmacological inhibition of ERK1/2 phosphorylation with U0126 or PD98059 resulted in a decrease in TNF-induced autophagy that was accompanied by an increase in cleavage of caspase-7, -8, -9 and PARP Furthermore, inhibition of ERK1/2 signalling resulted in decreased clonogenic capacity of MCF-7 cells. These data suggest that TNF-induces autophagy through ERK1/2 and that inhibition of autophagy increases cellular sensitivity to TNF.
authors.affiliation: Department of Molecular Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
authors.forename: U
authors.initials: U
authors.lastname: Sivaprasad
authors.forename: A
authors.initials: A
authors.lastname: Basu
mesh_terms: D001343:Autophagy / Q000187:drug effects*; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014410:Tumor Stem Cell Assay
chemical_list: C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D047428:Protein Kinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D011065:Poly(ADP-ribose) Polymerases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3