vitamin-k-semiquinone-radical and Cell-Transformation--Neoplastic

Vitamin K is a cofactor for γ-glutamyl carboxylase, which catalyzes the posttranslational conversion of specific glutamyl residues to γ-carboxyglutamyl residues in a variety of vitamin K-dependent proteins (VKDPs) involved in blood coagulation, bone and cartilage metabolism, signal transduction, and cell proliferation. Despite the great advances in the genetic, structural, and functional studies of VKDPs as well as the enzymes identified as part of the vitamin K cycle which enable it to be repeatedly recycled within the cells, little is known of the identity and roles of key regulators of vitamin K metabolism in mammals and humans. This review focuses on new insights into the molecular mechanisms underlying the intestinal absorption and in vivo tissue conversion of vitamin K1 to menaquinone-4 (MK-4) with special emphasis on two major advances in the studies of intestinal vitamin K transporters in enterocytes and a tissue MK-4 biosynthetic enzyme UbiA prenyltransferase domain-containing protein 1 (UBIAD1), which participates in the in vivo conversion of a fraction of dietary vitamin K1 to MK-4 in mammals and humans, although it remains uncertain whether UBIAD1 functions as a key regulator of intracellular cholesterol metabolism, bladder and prostate tumor cell progression, vascular integrity, and protection from oxidative stress.

Topics: Animals; Cell Transformation, Neoplastic; Cholesterol; Dimethylallyltranstransferase; Enterocytes; Humans; Intestinal Absorption; Mice; Neoplasms; Oxidative Stress; Vitamin K; Vitamin K 2

Topics: Acute Disease; Anticoagulants; Atrial Fibrillation; Cell Transformation, Neoplastic; Disseminated Intravascular Coagulation; Dose-Response Relationship, Drug; Embolization, Therapeutic; Female; Hemorrhage; Heparin; Humans; Mitral Valve; Postoperative Complications; Pregnancy; Pulmonary Embolism; Thrombocytopenia; Thromboembolism; Thrombophlebitis; Vitamin K; Warfarin

Simian Virus 40 Large T-antigen expressed in NIH3T3 cells increases p53 level and interacts with this tumor suppressor to form large nuclear complexes. We show here that T-antigen sensitizes NIH3T3 cells to low doses of the oxidative stress inducer menadione. This oxidant increased p53 accumulation and disrupted p53/T-antigen interaction, but not T-antigen/pRb, T-antigen/Hsc70 and p53/Hsc70 complexes; a phenomenon inhibited by the anti-oxidant N-acetyl-cysteine. Analysis of several p53 downstream gene products revealed that the level of Fas receptor, which was sharply reduced by T-antigen expression, was drastically increased in response to menadione treatment. Menadione also induced a T-antigen dependent cleavage of Fas ligand. Analysis performed with Fas receptor antagonist antibody and metalloproteinases inhibitor revealed that menadione triggers a Fas-dependent death of a fraction of T-antigen expressing cells. This Fas pathway does not activate caspase 8 or 3, probably because of the inhibition induced by T-antigen, and leads to a necrotic cell death which contributes at least in part to the hypersensitivity of T-antigen transformed cells to oxidative stress.

Topics: 3T3 Cells; Acetylcysteine; Animals; Antibodies; Antigens, Polyomavirus Transforming; Antioxidants; Apoptosis; Cell Survival; Cell Transformation, Neoplastic; fas Receptor; Mice; Necrosis; Oxidative Stress; Reactive Oxygen Species; Simian virus 40; Tumor Suppressor Protein p53; Vitamin K

Active oxygen (AO) is ubiquitous in nature and its many forms can act as natural carcinogens. Their effect on the transformation of a mouse myeloid progenitor cell line was studied using anchorage-independent colony formation in methylcellulose as the primary assay. Both cytotoxic and non-toxic concentrations of t-butylhydroperoxide, hydrogen peroxide and menadione were examined. At non-cytotoxic concentrations, no AO transformation of these cells from interleukin-3 dependence to factor independence (FI) was observed, even after as many as 25 treatments. At cytotoxic concentrations, however, all 3 classes of AO transformed the cells to FI growth. The most potent agent was t-butyl hydroperoxide (43-fold induction), followed by hydrogen peroxide and then menadione. As little as one exposure to cytotoxic levels of these oxidants induced significant transformation, with relative potencies the same as those observed for multiple exposures. These inductions were not due to general cytotoxic effects, since sodium fluoride and heat-shock treatment gave minimal inductions. AO-induced colonies in methylcellulose that were removed, examined and then injected into pre-irradiated mice uniformly produced tumors. Control, non-treated cells did not form tumors. Tumorigenic cells did not form colonies in methylcellulose at lower plating densities. Furthermore, low numbers of transformed cells supplemented to high density with normal cells showed a small but insufficient increase in colony number as compared with high-density cultures of transformed cells. Our results suggest that the transformants depend upon a paracrine mechanism of growth that is mediated by the transformed cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cell Count; Cell Division; Cell Line; Cell Transformation, Neoplastic; Dose-Response Relationship, Drug; Granulocytes; Hematopoietic Stem Cells; Hot Temperature; Hydrogen Peroxide; Interleukin-3; Male; Mice; Mice, Inbred DBA; Neoplasm Transplantation; Oxygen; Peroxides; Sodium Fluoride; tert-Butylhydroperoxide; Tetradecanoylphorbol Acetate; Vitamin K

The aim of this study has been to define cytotoxic mechanisms that may cause clonal expansion in the liver of pre-carcinogenic cells. An in vitro model, which has been described previously, was used. Hepatocytes were isolated from carcinogen-treated rats and a high proportion of the cells were gamma-glutamyltranspeptidase (GGT)-positive. The cells were incubated in suspension and exposed to toxic agents in concentrations that induced a moderate increase in cellular leakage within 3 h. Samples were withdrawn and sampled cells were then allowed to attach to collagen-coated plates. Attached cells were stained and the ratio of GGT-positive/GGT-negative cells (GGT-ratio) was determined. The initial GGT-ratio was 10.4 +/- 4.7% and an increased ratio was taken as a sign of toxicity that resulted in a selection of GGT-positive cells. In a first series of experiments it was shown that hydroquinone and menadione increase the GGT-ratio, while diquat, sodium selenite, diethyl maleate or phorone do not. However, diethyl maleate in combination with diquat increased the GGT-ratio. Hydrogen peroxide (5 mM) increased the GGT-ratio as effectively as hydroquinone (0.3 mM). Lower concentrations of H2O2 (0.05 mM) increased the GGT-ratio in GSH-depleted cells. The changes induced by hydroquinone and H2O2 in low concentration were reversible. In another series of experiments, plates coated with antibodies against beta 1-integrin were used. An increase in the GGT-ratio was obtained with anti beta 1-integrin, but not with broad spectrum anti-rat hepatocyte or anti-rat beta 2-microglobulin antibodies as substrata. These data suggested an involvement of the beta 1-integrin in the selection. Taken together, these data indicate that GGT-positive hepatocytes are protected against GSH depletion and oxidative stress that may result in reversible receptor alterations.

Topics: Animals; Biomarkers, Tumor; Cell Transformation, Neoplastic; Cells, Cultured; Collagen; Diethylnitrosamine; Diquat; Female; gamma-Glutamyltransferase; Glutathione; Hydrogen Peroxide; Hydroquinones; Ketones; Kinetics; Liver; Maleates; Phenobarbital; Rats; Receptors, Cell Surface; Receptors, Collagen; Selenium; Sodium Selenite; Vitamin K

Several hepatic peroxisome proliferators (HHPs) such as di(2-ethylhexyl)phthalate (DEHP), mono(2-ethylhexyl)-phthalate, clofibrate and tiadenol, induce morphological transformation of Syrian hamster embryo (SHE) cells in vitro. According to one hypothesis, the hepatocarcinogenic effect of HPPs is caused by an oxidative stress due to increased H2O2-production from the strongly induced peroxisomal beta-oxidation of fatty acids. Thus, increased transformation frequencies by HPPs should be obtained when catalase was inhibited by 3-amino-1,2,4-triazole (amitrole). However, co-exposure to HPPs and amitrole did not enhance the transformation frequencies for any of the HPPs. The sensitivity of SHE cells for oxidative agents was studied by using menadione and H2O2. Menadione only induced transformation at a toxic concentration, while H2O2 induced transformation at non-toxic concentrations. To study the generation of oxidative radicals in SHE cells, electron spin resonance was employed. No oxidative radical formation was detected in tiadenol- or DEHP-exposed SHE cells. When menadione or H2O2 were added during the measurements, oxidative radicals were found. A transmission electron microscopic study showed a small number of peroxisomes, and did not reveal any increase in the number of peroxisomes in clofibrate-treated SHE cells.

Topics: Amitrole; Animals; Catalase; Cell Line, Transformed; Cell Transformation, Neoplastic; Cells, Cultured; Clofibrate; Cricetinae; Diethylhexyl Phthalate; Electron Spin Resonance Spectroscopy; Fatty Alcohols; Hydrogen Peroxide; Liver; Mesocricetus; Microbodies; Vitamin K

Topics: Animals; Cell Transformation, Neoplastic; Naphthalenesulfonates; Neoplasm Metastasis; Neoplasms, Experimental; Radiation-Sensitizing Agents; Rats; Sarcoma, Experimental; Vitamin K

Topics: Animals; Cell Line; Cell Transformation, Neoplastic; Cytochrome c Group; Cytochromes; Embryo, Mammalian; Glucose; Haplorhini; Humans; In Vitro Techniques; Kidney; Liver; Lung; Mice; Oxidation-Reduction; Oxygen Consumption; Polarography; Simian virus 40; Skin; Spectrophotometry; Vitamin K

Topics: Cell Transformation, Neoplastic; Cybernetics; Diethylstilbestrol; Hot Temperature; Hydrogen Peroxide; Hydrogen-Ion Concentration; Membranes; Naphthoquinones; Neoplasms; Vitamin K