title: Extracellular matrix stimulates reactive oxygen species production and increases pancreatic cancer cell survival through 5-lipoxygenase and NADPH oxidase.
abstract: The extracellular matrix (ECM) facilitates pancreatic cancer cells survival, which is of central importance for pancreatic adenocarcinoma that is highly fibrotic. Here, we show that reactive oxygen species (ROS) mediate the prosurvival effect of ECM in human pancreatic cancer cells. Fibronectin and laminin stimulated ROS production and NADPH oxidase activation in pancreatic cancer cells. Both pharmacological and molecular approaches show that fibronectin stimulated ROS production through activation of NADPH oxidase and NADPH oxidase-independent pathways and that 5-lipoxygenase (5-LO) mediates both these pathways. Analyses of the mechanisms of ROS production by ECM proteins and growth factors indicate that activation of NADPH oxidase (Nox4) is a common mechanism employed both by ECM proteins and growth factors to increase ROS in pancreatic cancer cells. We also found that Nox4 is present in human pancreatic adenocarcinoma tissues and that these tissues display membrane NADPH oxidase activity. ECM proteins and growth factors activate NADPH oxidase through different mechanisms; in contrast to ECM proteins, growth factors activate NADPH oxidase through 5-LO-independent mechanisms. Inhibition of 5-LO or NADPH oxidase with pharmacological inhibitors of these enzymes and with Nox4 or 5-LO antisense oligonucleotides markedly stimulated apoptosis in cancer cells cultured on fibronectin. Our results indicate that ROS generation via 5-LO and downstream NADPH oxidase mediates the prosurvival effect of ECM in pancreatic cancer cells. These mechanisms may play an important role in pancreatic cancer resistance to treatments and thus represent novel therapeutic targets.
authors.affiliation: Department of Medicine, Veterans Affairs Greater Los Angeles Healthcare System, University of California Los Angeles, CA 90073, USA.
authors.forename: Mouad
authors.initials: M
authors.lastname: Edderkaoui
authors.forename: Peggy
authors.initials: P
authors.lastname: Hong
authors.forename: Eva C
authors.initials: EC
authors.lastname: Vaquero
authors.forename: Jong K
authors.initials: JK
authors.lastname: Lee
authors.forename: Lars
authors.initials: L
authors.lastname: Fischer
authors.forename: Helmut
authors.initials: H
authors.lastname: Friess
authors.forename: Markus W
authors.initials: MW
authors.lastname: Buchler
authors.forename: Markus M
authors.initials: MM
authors.lastname: Lerch
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Pandol
authors.forename: Anna S
authors.initials: AS
authors.lastname: Gukovskaya
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival; D024042:Collagen Type I / Q000494:pharmacology; D005109:Extracellular Matrix / Q000502:physiology*; D005353:Fibronectins / Q000494:pharmacology*; D006801:Humans; D007797:Laminin / Q000494:pharmacology*; D016859:Lipoxygenase Inhibitors; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors
chemical_list: D000975:Antioxidants; D024042:Collagen Type I; D005353:Fibronectins; D007797:Laminin; D016859:Lipoxygenase Inhibitors; D016376:Oligonucleotides, Antisense; D017382:Reactive Oxygen Species; D001094:Arachidonate 5-Lipoxygenase; D019001:Nitric Oxide Synthase; D014969:Xanthine Oxidase; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human