title: Influence of oxygen partial pressure on the characteristics of human hepatocarcinoma cells.
abstract: Most of the in vitro studies using liver cell lines have been performed under atmospheric oxygen partial pressure (21% O2). However, the oxygen concentrations in the liver and cancer cells are far from this value. In the present study, we have evaluated the influence of oxygen on 1) the tumor cell lines features (growth, steady-state ROS levels, GSH content, activities of antioxidant enzymes, p66 Shc and SOD expressions, metalloproteinases secretion, migration, invasion, and adhesion) of human hepatocellular carcinoma cell lines, and b) the response of the cells to an oxidant stimulus (aqueous leaf extract of the V. baccifera plant species). For this purpose, three hepatocarcinoma cell lines with different p53 status, HepG2 (wild-type), Huh7 (mutated), and Hep3B (deleted), were cultured (6-30 days) under atmospheric (21%) and more physiological (8%) pO2. Results showed that after long-term culturing at 8% versus 21% O2, the cellular proliferation rate and the steady-state levels of mitochondrial O2-were unaffected. However, the intracellular basal ROS levels were higher independently of the characteristics of the cell line. Moreover, the lower pO2was associated with lower glutathione content, the induction of p66 Shc and Mn-SOD proteins, and increased SOD activity only in HepG2. This cell line also showed a higher migration rate, secretion of active metalloproteinases, and a faster invasion. HepG2 cells were more resistant to the oxidative stress induced by V. baccifera. Results suggest that the long-term culturing of human hepatoma cells at a low, more physiological pO2induces antioxidant adaptations that could be mediated by p53, and may alter the cellular response to a subsequent oxidant challenge. Data support the necessity of validating outcomes from studies performed with hepatoma cell cultures under ambient O2.
authors.affiliation: Department of Physiology, Medicine and Nursing School, University of the Basque Country UPV/EHU, 48940 Leioa, Spain.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Trepiana
authors.affiliation: Department of Physiology, Medicine and Nursing School, University of the Basque Country UPV/EHU, 48940 Leioa, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Meijide
authors.affiliation: Department of Physiology, Medicine and Nursing School, University of the Basque Country UPV/EHU, 48940 Leioa, Spain.
authors.forename: Rosaura
authors.initials: R
authors.lastname: Navarro
authors.affiliation: Department of Physiology, Medicine and Nursing School, University of the Basque Country UPV/EHU, 48940 Leioa, Spain.
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Hernández
authors.affiliation: Department of Physiology, Medicine and Nursing School, University of the Basque Country UPV/EHU, 48940 Leioa, Spain. Electronic address: joseignacio.ruizs@ehu.eus.
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Ruiz-Sanz
authors.affiliation: Department of Physiology, Medicine and Nursing School, University of the Basque Country UPV/EHU, 48940 Leioa, Spain. Electronic address: mbego.ruizlarrea@ehu.eus.
authors.forename: M Begoña
authors.initials: MB
authors.lastname: Ruiz-Larrea
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress; D010100:Oxygen / Q000494:pharmacology*; D010313:Partial Pressure; D017382:Reactive Oxygen Species / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: D017382:Reactive Oxygen Species; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D005978:Glutathione; D010100:Oxygen
keywords: Cell migration; Hepatoma cells; Oxygen tension; Superoxide dismutase