title: Attenuation of LDHA expression in cancer cells leads to redox-dependent alterations in cytoskeletal structure and cell migration.
abstract: Aerobic glycolysis, the preferential use of glycolysis even in the presence of oxygen to meet cellular metabolic demands, is a near universal feature of cancer. This unique type of metabolism is thought to protect cancer cells from damaging reactive oxygen species (ROS) produced in the mitochondria. Using the cancer cell line MDA-MB-435 it is shown that shRNA mediated knockdown of lactate dehydrogenase A (LDHA), a key mediator of aerobic glycolysis, results in elevated mitochondrial ROS production and a concomitant decrease in cell proliferation and motility. Redox-sensitive proteins affected by oxidative stress associated with LDHA knockdown were identified by Redox 2D-PAGE and mass spectrometry. In particular, tropomyosin (Tm) isoforms Tm4, Tm5NM1 and Tm5NM5, proteins involved in cell migration and cytoskeletal dynamics, exhibited changes in disulfide bonding and co-localized with peri-nuclear actin aggregates in LDHA knockdown cells. In contrast, treatment with the thiol-based antioxidant N-acetylcysteine promoted the relocalization of Tms to cortical actin microfilaments and partially rescued the migration defects associated with attenuated LDHA expression. These results suggest that aerobic glycolysis and reduced mitochondrial ROS production create an environment conducive to cytoskeletal remodeling; key events linked to the high cell motility associated with cancer.
authors.affiliation: The Department of Biology, Western University, London, Ontario, Canada N6A 5B7.
authors.forename: Robert
authors.initials: R
authors.lastname: Arseneault
authors.forename: Andrew
authors.initials: A
authors.lastname: Chien
authors.forename: Jordan T
authors.initials: JT
authors.lastname: Newington
authors.forename: Tim
authors.initials: T
authors.lastname: Rappon
authors.forename: Richard
authors.initials: R
authors.lastname: Harris
authors.forename: Robert C
authors.initials: RC
authors.lastname: Cumming
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology*; D048708:Cell Growth Processes / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology*; D003599:Cytoskeleton / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D000080864:Lactate Dehydrogenase 5; D061986:MCF-7 Cells; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D017382:Reactive Oxygen Species; D007770:L-Lactate Dehydrogenase; D000080864:Lactate Dehydrogenase 5
keywords: Actin; Cell motility; Lactate dehydrogenase A; Redox regulation; Tropomyosin-3; Warburg effect