title: DNA oxidative damage during differentiation of HL-60 human promyelocytic leukemia cells.
abstract: DNA oxidative damage was measured in human promyelocytic leukemia HL-60 cells, in the same cells committed to granulocytic differentiation with dimethyl sulfoxide (DMSO) or all-trans-retinoic acid (RA) and in mature human peripheral granulocytes (HPG). DNA damage was evaluated as single strand breaks and 8-OHdG adducts, measured by single cell electrophoresis or by monoclonal antibodies, respectively. The basal levels of either marker of DNA damage were higher in undifferentiated HL-60 cells than in HPG and DMSO- or RA-differentiated cells. Treatment with H(2)O(2) increased 8-OHdG formation in all cells, but the levels of DNA damage remained higher in undifferentiated cells as compared to the differentiated ones. Three lines of evidence suggested that the higher levels of DNA damage observed in undifferentiated cells were at least in part attributable to a reduced detoxification of reactive oxygen species (ROS). First, undifferentiated cells were shown to accumulate higher levels of dichlorodihydrofluorescein-detectable ROS than HPG and DMSO- or RA-differentiated cells. Second, undifferentiated HL-60 cells were characterized by reduced levels of GSH and lower GSH/GSSG ratios as compared to the differentiated cells. Third, pretreatment of undifferentiated HL-60 cells with antioxidants such as alpha-tocopherol or beta-carotene suppressed the elevation of ROS and the formation of 8-OHdG induced by H(2)O(2). Further evidence for the importance of the oxidant/antioxidant balance was obtained by modulating the iron-catalyzed decomposition of H(2)O(2) to hydroxyl radicals in undifferentiated HL-60 cells. In fact, pretreatment with FeSO(4) increased the formation of 8-OHdG induced by H(2)O(2), whereas pretreatment with the iron chelator deferoxamine produced the opposite effect. These results illustrate correlations between the oxidant/antioxidant balance and DNA damage and suggest that the capability of a cell population to withstand oxidative stress and DNA damage may depend on its degree of differentiation.
authors.affiliation: Institute of General Pathology and Giovanni XXIII Cancer Research Center, Faculty of Medicine, Catholic University of Sacred Heart, Rome, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Covacci
authors.forename: A
authors.initials: A
authors.lastname: Torsello
authors.forename: P
authors.initials: P
authors.lastname: Palozza
authors.forename: A
authors.initials: A
authors.lastname: Sgambato
authors.forename: G
authors.initials: G
authors.lastname: Romano
authors.forename: A
authors.initials: A
authors.lastname: Boninsegna
authors.forename: A
authors.initials: A
authors.lastname: Cittadini
authors.forename: F I
authors.initials: FI
authors.lastname: Wolf
mesh_terms: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents / Q000009:adverse effects*; D000975:Antioxidants; D002454:Cell Differentiation; D002470:Cell Survival; D018736:DNA Adducts; D004249:DNA Damage; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004586:Electrophoresis; D016166:Free Radical Scavengers / Q000494:pharmacology; D018922:HL-60 Cells / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014212:Tretinoin / Q000009:adverse effects*
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D000975:Antioxidants; D018736:DNA Adducts; D016166:Free Radical Scavengers; D016877:Oxidants; D017382:Reactive Oxygen Species; D014212:Tretinoin; D006861:Hydrogen Peroxide; D004121:Dimethyl Sulfoxide