title: Plasma membrane oxidoreductase activity in cultured cells in relation to mitochondrial function and oxidative stress.
abstract: Dichlorophenol indophenol (DCIP) reduction by intracellualr pyridine nucleotides was investigated in two different lines of cultured cells characterized by enhanced production of reacive oxygen species (ROS) with respect to suitable controls. The first line denominated XTC-UC1 was derived from a metastasis of an oxyphilic thyroid tumor characterized by mitochondrial hyperplasia and compared with a line (B-CPAP) derived from a papillary thyroid carcinoma with normal mitochondrial mass. The second line (170 MN) was a cybrid line derived from rho0 cells from an osteosarcoma line (143B) fused with platelets from a patient with a nucleotide 9957 mutation in mitochondrial DNA (encoding for cytochrome c oxidase subunit III) in comparison with the parent 143B line. The experimental lines had no major decreases of electron transfer activities with respect to the controls; both of them, however, exhibited an increased peroxide production. The XTC-UC1 cell line exhibited enhanced activity with respect to control of dicoumarol-sensitive DCIP reduction, identified with membrane bound DT-diaphorase, whereas dicoumarol insensitive DCIP reduction was not significantly changed. On the other hand the mtDNA mutated cybrids exhibited a strong increase of both dicoumarol sensitive and insensitive DCIP reduction. The results suggest that enhanced oxidative stress and not deficient respiratory activity per se is the stimulus triggering over-expression of plasma membrane oxidative enzymes.
authors.affiliation: Dipartimento di Biochimica, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Deleonardi
authors.forename: Annalisa
authors.initials: A
authors.lastname: Biondi
authors.forename: Marilena
authors.initials: M
authors.lastname: D'Aurelio
authors.forename: Milena Merlo
authors.initials: MM
authors.lastname: Pich
authors.forename: Karmen
authors.initials: K
authors.lastname: Stankov
authors.forename: Anna
authors.initials: A
authors.lastname: Falasca
authors.forename: Gabriella
authors.initials: G
authors.lastname: Formiggini
authors.forename: Carla
authors.initials: C
authors.lastname: Bovina
authors.forename: Giovanni
authors.initials: G
authors.lastname: Romeo
authors.forename: Giorgio
authors.initials: G
authors.lastname: Lenaz
mesh_terms: D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000201:enzymology*; D005260:Female; D006801:Humans; D007700:Kinetics; D008928:Mitochondria / Q000502:physiology*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010088:Oxidoreductases / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013964:Thyroid Neoplasms
chemical_list: D017382:Reactive Oxygen Species; D010088:Oxidoreductases; D016660:NAD(P)H Dehydrogenase (Quinone)