8-hydroxy-2--deoxyguanosine and Fibrosarcoma

Pycnogenol (PYC), polyphenolic compounds with antioxidant activity, acted as a prooxidant. PYC caused oxidative stress in human fibrosarcoma cells (HFS) when administered following pretreatment with iron chloride. The generated reactive oxygen species (ROS) caused the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA and resulted in more apoptosis in HFS cells than in the human fibroblastoma (HFB) cells. DNA damage and cellular viability at different PYC concentrations were closely consistent with cell growth, high performance liquid chromatography (HPLC), Enzyme Linked Immunosorbent Assay (ELISA) and assays of two major antioxidant enzymes, superoxide dismutase (SOD) and catalase. Although the presence of PYC induced total SOD and catalase activities under oxidative stress in dose dependent fashion, more apoptotic cells were induced in HFS cells with increased [8-OHdG] than in HFB cells. The results suggest that PYC selectively induced cell death in HFS cells. This further confirmed that PYC-induced apoptosis is mediated primarily through the activation of caspase-3 apoptotic marker in HFS cells but not in HFB cells. We conclude that PYC would behave as either antioxidant or prooxidant dependant upon the cellular types.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Apoptosis; Cell Line, Tumor; Cell Survival; Chromatography, High Pressure Liquid; Deoxyguanosine; DNA Damage; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Ferrous Compounds; Fibroblasts; Fibrosarcoma; Flavonoids; Free Radical Scavengers; Humans; Oxidative Stress; Plant Extracts

Nanoparticles are prevalent in both commercial and medicinal products; however, the contribution of nanomaterials to carcinogenesis remains unclear. We therefore examined the effects of nano-sized titanium dioxide (TiO(2)) on poorly tumorigenic and nonmetastatic QR-32 fibrosarcoma cells. We found that mice that were cotransplanted subcutaneously with QR-32 cells and nano-sized TiO(2), either uncoated (TiO(2)-1, hydrophilic) or coated with stearic acid (TiO(2)-2, hydrophobic), did not form tumors. However, QR-32 cells became tumorigenic after injection into sites previously implanted with TiO(2)-1, but not TiO(2)-2, and these developing tumors acquired metastatic phenotypes. No differences were observed either histologically or in inflammatory cytokine mRNA expression between TiO(2)-1 and TiO(2)-2 treatments. However, TiO(2)-2, but not TiO(2)-1, generated high levels of reactive oxygen species (ROS) in cell-free conditions. Although both TiO(2)-1 and TiO(2)-2 resulted in intracellular ROS formation, TiO(2)-2 elicited a stronger response, resulting in cytotoxicity to the QR-32 cells. Moreover, TiO(2)-2, but not TiO(2)-1, led to the development of nuclear interstices and multinucleate cells. Cells that survived the TiO(2) toxicity acquired a tumorigenic phenotype. TiO(2)-induced ROS formation and its related cell injury were inhibited by the addition of antioxidant N-acetyl-l-cysteine. These results indicate that nano-sized TiO(2) has the potential to convert benign tumor cells into malignant ones through the generation of ROS in the target cells.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Cell Line, Tumor; Cell Transformation, Neoplastic; Cytokines; Deoxyguanosine; Dinoprostone; Female; Fibrosarcoma; Intercellular Signaling Peptides and Proteins; Mice; Mice, Inbred C57BL; Nanoparticles; Neoplasm Invasiveness; Particle Size; Reactive Oxygen Species; Thymosin; Titanium; Vascular Endothelial Growth Factor A

We have used two tumor cell clones (B9 and G2), derived from the methylcholanthrene-induced murine fibrosarcoma GR9 and normal BALB/c3T3 fibroblasts, to study the ability of t-BOOH derived reactive oxygen radicals to induce oxidative stress, apoptosis and c-fos and c-jun mRNA transcription. These clones differ in terms of their major histocompatibility complex (MHC) (H-2) class I genes expression, their tumor induction and metastatic potential and their reduced glutathione (GSH) levels. Incubation of both cell clones in the presence of t-BOOH results in the increase of 8-oxo-2'-deoxyguanosine (8-oxo-dG) and malondialdehyde and the decrease of GSH. The xenobiotic also induces the transcription of c-fos and c-jun mRNAs in normal fibroblasts and in B9 cell clone but not in G2 cell clone. In addition, G2 cell clone is more resistant to apoptosis when compared with normal fibroblasts or B9 cell clone. Higher levels of GSH in G2 cell clone may be the reason of their lower transactivation response and apoptosis. Thus lowering GSH concentration may be convenient not only for the efficiency of chemotherapy but also to induce a rather fast and direct apoptosis mechanisms in tumor cells. Most commonly antioxidants tested, superoxide dismutase, catalase, GSH and thiourea, were effective in the inhibition of t-BOOH-induced c-fos and c-jun mRNA transcription in normal fibroblasts suggesting, as expected, that different oxygen species are involved in the observed effects induced by the xenobiotic.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Apoptosis; BALB 3T3 Cells; Deoxyguanosine; DNA Primers; Fibroblasts; Fibrosarcoma; Gene Expression Regulation; Glutathione; Histocompatibility Antigens Class I; Malondialdehyde; Mice; Oxidative Stress; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; tert-Butylhydroperoxide; Transcription, Genetic; Tumor Cells, Cultured

QR-32 tumor cells, a clone derived from a murine fibrosarcoma, are poorly tumorigenic and nonmetastatic when injected into syngeneic C57BL/6 mice. However, they are converted to highly malignant ones once they have grown in vivo after being co-implanted in a subcutaneous site with a foreign body, a gelatin sponge. Early phase of inflammation induced by the gelatin sponge participates in the conversion and histological analysis shows predominant infiltration of neutrophils. The objective of this study was to determine whether the depletion of the infiltrating neutrophils has any effect on the tumor progression. Intraperitoneal administration of a monoclonal anti-granulocyte antibody, RB6-8C5 (RB6), depleted neutrophils from both the peripheral blood circulation and the local inflamed site in mice with co-implantation of QR-32 tumor cells and gelatin sponge. The RB6 administration did not inhibit either tumor development or growth of QR-32 tumor cells. In contrast, tumor cell lines established from RB6-administered mice showed a significant decrease in metastatic incidence as compared with the tumor cell lines obtained from the mice with administration of control rat IgG or saline. Metastatic ability was significantly suppressed when RB6 had been administered in the early phase (from day -2 to day 6 after implantation); however, the administration in the middle (from day 6 to day 14) or late (from day 14 to day 22) phase did not affect the metastatic ability. We confirmed the phenomena by using integrin beta(2) knockout mice that had impaired neutrophil infiltration into inflamed sites. In the knockout mice, neutrophils hardly infiltrated into the gelatin sponge and the tumors showed dramatically suppressed metastatic phenotype as compared with those in wild-type mice or nude mice. Immunohistochemical analysis demonstrated that expressions of 8-hydroxy-2'-deoxyguanosine and nitrotyrosine were parallel to those in the presence of neutrophils. These results suggested that inflammation, especially when neutrophils infiltrate into tumor tissue, is primarily important for benign tumor cells to acquire metastatic phenotype.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antibodies, Monoclonal; Blood Cells; CD18 Antigens; Cell Line, Tumor; Complement System Proteins; Cytotoxicity, Immunologic; Deoxyguanosine; Disease Progression; Drug Administration Schedule; Fibrosarcoma; Granulocytes; Immunohistochemistry; Inflammation; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Nude; Neutrophil Infiltration; Neutrophils; Phenotype; Time Factors; Tyrosine

The effect of t-butyl hydroperoxide (t-BOOH) on the induction of the Major Histocompatibility Complex (MHC) class I genes has been studied in two cell clones (B9 and G2) of the methylcholanthrene-induced murine fibrosarcoma GR9. These two clones were selected based on their different biological and biochemical behavior specially related to their tumor induction capability when injected into a BALB/c mouse. t-BOOH (0.125 mM) induced the expression of H-2 molecules in both cell clones. In B9 cell clone, in which MHC basal expression is very low or absent, t-BOOH significantly induced H-2Kd, H-2Dd and H-2Ld molecules. In G2 cell clone the expression of MHC class I genes was also enhanced by the xenobiotic, the effect being especially significant on the H-2Ld molecule which is not expressed under basal conditions. H-2 molecules expression was accompanied by the activation of the transactivator factor NF kappa B. These results suggest that oxidative stress may modulate the antigen expression of tumor cells and thus the immune response of the host organism. Basal levels of oxidative parameters, such as anti-oxidant enzymes, malondialdehyde (MDA) and the DNA damaged base 8-hydroxy-2'-deoxyguanosine (8-OHdG), showed differences between the two fibrosarcoma cell clones.

Topics: 3T3 Cells; 8-Hydroxy-2'-Deoxyguanosine; Animals; Catalase; Deoxyguanosine; Electrophoretic Mobility Shift Assay; Fibrosarcoma; Flow Cytometry; Gene Expression Regulation; Glutathione; Glutathione Peroxidase; Histocompatibility Antigens Class I; Major Histocompatibility Complex; Malondialdehyde; Methylcholanthrene; Mice; Mice, Inbred BALB C; NF-kappa B; Oxidative Stress; Superoxide Dismutase; tert-Butylhydroperoxide; Tumor Cells, Cultured