ascorbic-acid and Liver-Neoplasms

Iron is essential for life, but iron overload is toxic and potentially fatal. The liver is a major site of iron storage and is particularly susceptible to injury from iron overload, especially when (as in primary hemochromatosis) the iron accumulates in hepatocytes. Iron can be taken up by the liver in several forms and by several pathways including: (1) receptor-mediated endocytosis of diferric or monoferric transferrin or ferritin, (2) reduction and carrier-facilitated internalization of iron from transferrin without internalization of the protein moiety of transferrin, (3) electrogenic uptake of low molecular weight, non-protein bound forms of iron, and (4) uptake of heme from heme-albumin, heme-hemopexin, or hemoglobin-haptoglobin complexes. Normally, pathway 2 is probably the major one for uptake of iron by hepatocytes. Iron is stored in the liver in the cores of ferritin shells and as hemosiderin, an insoluble product derived from iron-rich ferritin. Iron in hepatocytes stimulates translation of ferritin mRNA and represses transcription of DNA for transferrin and transferrin receptors. The major pathologic effects of chronic hepatic iron overload are: (1) fibrosis and cirrhosis, (2) porphyria cutanea tarda, and (3) hepatocellular carcinoma. Although precise pathogenetic mechanisms remain unknown, iron probably produces these and other toxic effects by increasing oxidative stress and lysosomal lability. Vigorous efforts at diagnosis and treatment of iron overload are essential since the pathologic effects of iron are totally preventable by early vigorous iron removal and prevention of iron re-accumulation.

Topics: Ascorbic Acid; Carcinoma, Hepatocellular; Collagen; Free Radicals; Hemochromatosis; Humans; Iron; Liver; Liver Cirrhosis; Liver Neoplasms; Lysosomes; Membrane Potentials; Porphyrias; Potassium; Transferrin; Uroporphyrins; Vitamin E

Carcinogenicity tests showed that addition of the antioxidant BHA to the diet of F344 rats induced high incidences of papilloma and squamous cell carcinoma of the forestomach of both sexes. Male hamsters given BHA for 24 weeks also developed papilloma showing downward growth into the submucosa of the forestomach. These results indicate that BHA should be classified in the category of "sufficient evidence of carcinogenicity" as judged by IARC criteria. The 3-tert isomer of BHA seemed to be responsible for the carcinogenicity of crude BHA in the forestomach of rats. BHT was not found to be carcinogenic in rats or mice. In two-stage carcinogenesis in rats after appropriate initiation, BHA enhanced carcinogenesis in the forestomach and urinary bladder of rats, but inhibited carcinogenesis in the liver. BHT enhanced the induction of urinary bladder tumors and inhibited that of liver tumors, but had no effect on carcinogenesis in the forestomach. BHT could be a promoter of thyroid carcinogenesis. Sodium L-ascorbate enhanced forestomach and urinary bladder carcinogenesis. Ethoxyquin enhanced kidney and urinary bladder carcinogenesis, but inhibited liver carcinogenesis. Thus, these antioxidants modify two-stage chemical carcinogenesis in the forestomach, liver, kidney, urinary bladder, and thyroid, but show organ-specific differences in effects.

Topics: Animals; Anisoles; Antioxidants; Ascorbic Acid; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Cocarcinogenesis; Drug Synergism; Humans; Kidney Neoplasms; Liver Neoplasms; Methylnitrosourea; Neoplasms; Species Specificity; Stomach Neoplasms; Urinary Bladder Neoplasms

Topics: Ammonia; Animal Nutritional Physiological Phenomena; Animals; Ascorbic Acid; Colonic Neoplasms; Copper; Cricetinae; Dietary Fats; Dietary Fiber; Dietary Proteins; Energy Intake; Female; Humans; Iodine; Lipotropic Agents; Liver Neoplasms; Mammary Neoplasms, Experimental; Mice; Neoplasms; Neoplasms, Experimental; Nutritional Physiological Phenomena; Rats; Riboflavin; Selenium; Skin Neoplasms; Vitamin A; Vitamin B Complex; Zinc

Pharmacological ascorbate (P-AscH

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Female; Humans; Hydrogen Peroxide; Liver Neoplasms; Mice; Mice, Nude; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms, Experimental; Neoplastic Cells, Circulating; Pancreatic Neoplasms; Peroxides

To observe the regulatory effect of Bushen Jianpi Recipe (BSJPR) on cellular immunity the of primary liver cancer patients of Gan-Shen yin-deficiency and Pi qi-deficiency syndrome type after intervention therapy.. According to the multi-center randomized controlled principle, 117 patients after transcatheter arterial chemoembolization (TACE) were assigned to two groups, 60 in the treated group and 57 in the control group, who were treated respectively with BSJPR and liver protecting remedy (silymarin and vitamin c) for 12 weeks. Changes in TCM syndrome, quality of life (QOL), immediate effect on tumor size and survival time were observed. Meantime, the cellular immune function was also observed, including the T lymphocyte response determined by 3H-TdR, expression of MHC class I/II and B7 molecule detected by FACS, and interleukin 10 and 12 (IL-10, IL-12), interferon-gamma (IFN-gamma) tested by ELISA.. In the treated group after treatment, the efficacy for improving TCM syndrome reached 73.33% (44/60 cases), their half-year survival rate being 83.33% (50/60 cases); while those in the control group were 52.63% (30/57 cases) and 70.18% (40/57 cases) respectively, significant difference was shown between the two groups (P <0.05). The patients' QOL was improved in the treated group after treatment, with no obvious adverse reaction. However, the clinical benefit rate in the control group (92.7%, 51/55 cases) was higher than that in the treated group (78.0%, 46/59 cases, P =0. 035). Laboratory examination showed increases of MHC class II (CD14+/HLA-DR) expression on monocyte surface as well as IFN-gamma and IL-12 production in the treated group.. Using BSJPR together with TACE could enhance patients' cellular immune function to elevate the clinical curative effect on primary liver cancer.

Topics: Adult; Aged; Ascorbic Acid; Drugs, Chinese Herbal; Female; Humans; Liver Neoplasms; Male; Middle Aged; Silymarin; T-Lymphocytes; Treatment Outcome

Recent studies on HCC treatment reveal a tendency to use combined immuno-chemo-therapy. Additionally, new agents have been suggested in this field. We therefore studied 7 patients with proven inoperable HCC who were treated in accordance with the following protocol, and 5 untreated patients used as controls. Therapeutic trial: 1) 1FNa (Roferon): 6 MU x 7 days consecutively every 3 weeks, 2) Adriamycin (doxorubicin): 60 mg/m2 i. v. once every 3 weeks (500 mg total dose), 3) Tamoxifen: 10 mg p.o. twice daily continuously 4) Desferrioxamine (DFO): 500 mg i.m. daily x 7 days consecutively every 3 weeks, 5) ascorbic acid: 300 mg p.o. daily 1 hour after DFO administration x 7 days consecutively every 3 weeks. Follow-up studies were performed monthly and comprised clinical, biochemical, radiological and immunological (T-cell subsets, NK cells, monocyte-macrophage function, IL-2r expression, HLA-DR expression) parameters. Compared with the control group, the treated group had a longer survival rate (p < 0.001), increased tumor regression and less progressive disease. Immunologically, the treated patients with the maintenance of a sufficient immune status were associated with a prolonged survival rate. No serious side effects of the regimen were observed. In conclusion, IFNa combined with chemohormonal therapy appears to be beneficial in HCC patients. In addition, a prolonged survival rate might correlate with the maintenance of an adequate immune status in the patients.

Topics: Antineoplastic Combined Chemotherapy Protocols; Ascorbic Acid; Carcinoma, Hepatocellular; Combined Modality Therapy; Deferoxamine; Doxorubicin; Drug Administration Schedule; Female; Humans; Interferon alpha-2; Interferon-alpha; Liver Neoplasms; Male; Middle Aged; Recombinant Proteins; Survival Rate; Tamoxifen

Lenvatinib has become a first-line drug in the treatment of advanced hepatocellular carcinoma (HCC). Investigating its use in combination with other agents is of great significance to improve the sensitivity and durable response of Lenvatinib in advanced HCC patients. Vitamin C (L-ascorbic acid, ascorbate, VC) is an important natural antioxidant, which has been reported to show suppressive effects in cancer treatment. Here, we investigated the effect of the combination of VC and Lenvatinib in HCC cells

Topics: Antineoplastic Agents; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Line, Tumor; Humans; Liver Neoplasms

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, so we should be concerned and look for effective/less-harmful treatments than chemotherapeutics already clinically in application. Aspirin works well ''in conjunction'' with other therapies for HCC since aspirin can boost the sensitivity of anti-cancer activity. Vitamin C also was shown to have antitumor effects. In this study, we examined the anti-HCC activities of synergistic combination (aspirin and vitamin C) vs. doxorubicin on HCC-bearing rats and hepatocellular carcinoma (HepG-2) cells.. Based on our results, aspirin plus vitamin C can be considered reliable, accessible, and efficient synergistic anti-HCC medication.

Topics: Animals; Ascorbic Acid; Aspirin; Carcinoma, Hepatocellular; Doxorubicin; Humans; Liver Neoplasms; Rats; Thioacetamide; Tumor Suppressor Protein p53; Vitamins

Over production of reactive oxygen species (ROS) caused by altered redox regulation of signaling pathways is common in many types of cancers. While PET imaging is recognized as the standard tool for cancer imaging, there are no clinically-approved PET radiotracers for ROS-imaging in cancer diagnosis and treatment. An ascorbate-based radio ligand promises to meet this urgent need. Our laboratory recently synthesized [

Topics: Animals; Ascorbic Acid; Doxorubicin; Head and Neck Neoplasms; Ligands; Liver Neoplasms; Male; Mice; Primates; Rats; Reactive Oxygen Species; Rodentia; Squamous Cell Carcinoma of Head and Neck; Tissue Distribution

Hepatocellular carcinoma (HCC) is a leading cause of cancer death worldwide. Because of its high recurrence rate and heterogeneity, effective treatment for advanced stage of HCC is currently lacking. There are accumulating evidences showing the therapeutic potential of pharmacologic vitamin C (VC) on HCC. However, the metabolic basis underlying the anticancer property of VC remains to be elucidated. In this study, we used a high-resolution proton nuclear magnetic resonance-based metabolomics technique to assess the global metabolic changes in HCC cells following VC treatment. In addition, the HCC cells were also treated with oxaliplatin (OXA) to explore the potential synergistic effect induced by the combined VC and OXA treatment. The current metabolomics data suggested different mechanisms of OXA and VC in modulating cell growth and metabolism. In general, VC treatment led to inhibition of energy metabolism via NAD

Topics: Ascorbic Acid; Carcinoma, Hepatocellular; Humans; Liver Neoplasms; Magnetic Resonance Spectroscopy; Metabolome; Neoplasm Recurrence, Local; Oxaliplatin; Proton Magnetic Resonance Spectroscopy; Protons

Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor essential for cancer cell survival. The reprogramming of lipid metabolism has emerged as a hallmark of cancer, yet the relevance of HIF-1α to this process remains elusive. In this study, we profile HIF-1α-interacting proteins using proteomics analysis and identify fatty acid-binding protein 5 (FABP5) as a critical HIF-1α-binding partner. In hepatocellular carcinoma (HCC) tissues, both FABP5 and HIF-1α are upregulated, and their expression levels are associated with poor prognosis. FABP5 enhances HIF-1α activity by promoting HIF-1α synthesis while disrupting FIH/HIF-1α interaction at the same time. Oleic-acid treatment activates the FABP5/HIF-1α axis, thereby promoting lipid accumulation and cell proliferation in HCC cells. Our results indicate that fatty-acid-induced FABP5 upregulation drives HCC progression through HIF-1-driven lipid metabolism reprogramming.

Topics: Ascorbic Acid; Carcinoma, Hepatocellular; Cell Proliferation; Cell Survival; Cytosol; Fatty Acid-Binding Proteins; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lipid Metabolism; Liver Neoplasms; Mixed Function Oxygenases; Oleic Acid; Repressor Proteins

Nineteen organoselenides were synthesized and tested for their intrinsic cytotoxicity in hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF-7) cell lines and their corresponding selective cytotoxicity (SI) was estimated using normal lung fibroblast (WI-38) cells. Most of the organic selenides exhibited good anticancer activity, and this was more pronounced in HepG2 cells. Interestingly, the naphthoquinone- (5), thiazol- (12), and the azo-based (13) organic selenides demonstrated promising SI (up to 76). Furthermore, the amine 4c, naphthoquinone 5, and azo-based 13 and 15 organic selenides were able to down-regulate the expression of Bcl-2 and up-regulate the expression levels of IL-2, IL-6 and CD40 in HepG2 cells compared to untreated cells. Moreover, most of the synthesized candidates manifested good free radical-scavenging and GPx-like activities comparable to vitamin C and ebselen. The obtained results suggested that some of the presented organoselenium candidates have promising anti-HepG2 and antioxidant activities.

Topics: Antineoplastic Agents; Antioxidants; Biphenyl Compounds; Breast Neoplasms; Carcinoma, Hepatocellular; Cell Line; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Hep G2 Cells; Humans; Liver Neoplasms; MCF-7 Cells; Molecular Structure; Organoselenium Compounds; Picrates; Structure-Activity Relationship

Although human liver tumor cells have reduced metabolic functions as compared to primary human hepatocytes (PHH) they are widely used for pre-screening tests of drug metabolism and toxicity. The aim of the present study was to modify liver cancer cell lines in order to improve their drug-metabolizing activities towards PHH. It is well-known that epigenetics is strongly modified in tumor cells and that epigenetic regulators influence the expression and function of Cytochrome P450 (CYP) enzymes through altering crucial transcription factors responsible for drug-metabolizing enzymes. Therefore, we screened the epigenetic status of four different liver cancer cell lines (Huh7, HLE, HepG2 and AKN-1) which were reported to have metabolizing drug activities. Our results showed that HepG2 cells demonstrated the highest similarity compared to PHH. Thus, we modified the epigenetic status of HepG2 cells towards 'normal' liver cells by 5-Azacytidine (5-AZA) and Vitamin C exposure. Then, mRNA expression of Epithelial-mesenchymal transition (EMT) marker SNAIL and CYP enzymes were measured by PCR and determinate specific drug metabolites, associated with CYP enzymes by LC/MS. Our results demonstrated an epigenetic shift in HepG2 cells towards PHH after exposure to 5-AZA and Vitamin C which resulted in a higher expression and activity of specific drug metabolizing CYP enzymes. Finally, we observed that 5-AZA and Vitamin C led to an increased expression of Hepatocyte nuclear factor 4α (HNF4α) and E-Cadherin and a significant down regulation of Snail1 (SNAIL), the key transcriptional repressor of E-Cadherin. Our study shows, that certain phase I genes and their enzyme activities are increased by epigenetic modification in HepG2 cells with a concomitant reduction of EMT marker gene SNAIL. The enhancing of liver specific functions in hepatoma cells using epigenetic modifiers opens new opportunities for the usage of cell lines as a potential liver in vitro model for drug testing and development.

Topics: Ascorbic Acid; Azacitidine; Biomarkers, Tumor; Chromatin; Cytochrome P-450 Enzyme System; Down-Regulation; Epigenesis, Genetic; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Hepatocyte Nuclear Factor 4; Hepatocytes; Humans; Hydrocortisone; Insulin; Liver Neoplasms; Pharmaceutical Preparations; Snail Family Transcription Factors; Xenobiotics

Inspired by the special reducing capability of ascorbic acid (AA), ascorbic acid 2-phosphate (AA2P) has been extensively utilized as a substrate in current alkaline phosphatase (ALP) activity assays owing to the ALP-triggered transformation of AA2P into AA. However, such assays usually require AA-related complicated and laborious synthesis and/or signal generation procedures. Herein, we report an interesting in situ fluorogenic interaction between o-phenylenediamine (OPD) and AA, which inspires us to put forward a novel and simple AA2P/OPD-participated fluorescence turn-on ALP activity assay for the first time, and then the corresponding ALP-based fluorescence enzyme-linked immunosorbent assay (ELISA) has also been developed by means of the conventional ELISA platforms. According to the convenient and facile detection process with clear response mechanism, our fluorogenic reaction-based assay exhibits good sensitivity, selectivity, and excellent sensing performance, which ensures fluorescence ELISA to potentially be applied in clinical diagnosis by employing a well-studied biomarker of hepatocellular carcinoma, α-fetoprotein (AFP) as the model analyte. Such original ELISA via in situ formation of fluorophore from scratch gives a new sight to develop other potential immunoassay platforms in early clinical diagnosis by controlling the target antigens in the near future.

Topics: Alkaline Phosphatase; Ascorbic Acid; Carcinoma, Hepatocellular; Enzyme-Linked Immunosorbent Assay; Fluorescence; Fluorescent Dyes; Humans; Liver Neoplasms; Molecular Structure; Phenylenediamines

The aim of this study was to investigate the anticancer effect of a combination of D-fraction polysaccharide from Grifola frondosa (DFP) and vitamin C (VC) on hepatocellular carcinoma in vitro. DFP is a bioactive extract from the maitake mushroom. Anticancer activity was demonstrated using various concentrations of DFP alone or in combination with VC against the human hepatocarcinoma SMMC-7721 cell line. To investigate the anticancer mechanism, studies designed to detect cell apoptosis were conducted. Results from the MTT assay indicated that a combination of DFP (0.2 mg/mL) and VC (0.3 mmol/L) led to a 70% reduction in cell viability. Flow cytometry results indicated that DFP/VC treatment induced apoptosis in approximately 65% SMMC-7721 cells. Cell cycle analysis identified cell cycle arrest at the G2/M phase following DFP/VC treatment for 48 hours. In addition, cellular morphological changes were observed using transmission electron microscopy. Western blot analysis revealed that the upregulation of BAX, downregulation of Bcl-2, activation of poly-(ADP-ribose)-polymerase (PARP), and the release of cytochrome c were observed in cells treated with the combination of DFP/VC, which showed that the mechanism of anticancer activity in the SMMC-7721 hepatocarcinoma cells involved induction of apoptosis.

Topics: Antineoplastic Agents; Apoptosis; Ascorbic Acid; bcl-2-Associated X Protein; Biological Factors; Carcinoma, Hepatocellular; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Survival; Down-Regulation; Drug Synergism; G2 Phase Cell Cycle Checkpoints; Grifola; Humans; Liver Neoplasms; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Up-Regulation

Novel tetrazole-based diselenides and selenoquinones were synthesized via azido-Ugi and sequential nucleophilic substitution (SN) strategy. Molecular docking study into mammalian TrxR1 was used to predict the anticancer potential of the newly synthesized compounds. The cytotoxic activity of the compounds was evaluated using hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF-7) cancer cells and compared with their cytotoxicity in normal fibroblast (WI-38) cells. The corresponding redox properties of the synthesized compounds were assessed employing 2,2-diphenyl-1-picrylhydrazyl (DPPH), glutathione peroxidase (GPx)-like activity and bleomycin dependent DNA damage. In general, diselenides showed preferential cytotoxicity to HepG2 compared to MCF-7 cells. These compounds exhibited also good GPx catalytic activity compared to ebselen (up to 5 fold). Selenoquinones 18, 21, 22 and 23 were selected to monitor the expression levels of caspase-8, Bcl-2 and Ki-67 molecular biomarkers. Interestingly, these compounds downregulated the Bcl-2 and Ki-67 expression levels and activated the expression of caspase-8 in HepG2 cells compared to untreated cells. These results indicate that some of the newly synthesized compounds possess anti-HepG2 activity.

Topics: Antineoplastic Agents; Antioxidants; Carcinoma, Hepatocellular; Cell Line, Tumor; Chemistry Techniques, Synthetic; Computer Simulation; Humans; Liver Neoplasms; Molecular Docking Simulation; Organoselenium Compounds; Protein Domains; Tetrazoles; Thioredoxin Reductase 1

Liver metastatic disease is the main cause of death in colorectal cancer (CRC) patients. During metastatic spread of the disease an imbalance in the oxidative stress and inflammation plays a crucial role in tumor progression. In order to improve the efficacy of current therapies, new complementary therapeutic approaches are being analyzed including biologically active compounds with low side effects. The anti-inflammatory and anti-oxidant properties of Ocoxin® oral solution (OOS) prompt us to analyze its effect on the metastatic development of CRC to the liver. First, in vitro effect of OOS in tumor cell viability and migration was analyzed. Second, in vivo effect of different dosage patterns and concentrations in the development of hepatic metastasis was analyzed by intra-splenic inoculation of C26 colon carcinoma cells in Balb/c mice. Third, the expression of alpha smooth muscle actin, caspase-3 and Ki-67 expression was quantified by immunohistochemistry, then gene expression levels of inflammatory factors were measured by quantitative RT-PCR. According to our results, OOS reduced tumor cell viability and migration in vitro. Moreover, in vivo daily administration of OOS from the 7th day after tumor cell inoculation decreased the total area and size of metastatic foci in the liver. Furthermore, cell proliferation and fibroblast recruitment was decreased in tumor foci while a higher number of apoptotic cells were observed. Finally, RNA levels for the inflammatory mediators COX-2, IFNγ, IL1β, IL6 and TNFα were reduced in total liver. In conclusion, OOS reduced the metastatic development of colorectal cancer to the liver by increasing apoptosis, and decreasing tumor cell proliferation and fibroblast recruitment in the tumor foci, as well as the expression of inflammatory mediators in total liver. These results point out OOS as a potential supplement to be applied as complementary therapy for the treatment of liver metastasis from colorectal cancer.

Topics: Animals; Apoptosis; Ascorbic Acid; Caspase 3; Cell Proliferation; Colorectal Neoplasms; Folic Acid; Gene Expression Regulation, Neoplastic; Glycyrrhizic Acid; Humans; Ki-67 Antigen; Liver Neoplasms; Mice; Mice, Inbred BALB C; Neoplasm Proteins; Pantothenic Acid; Plant Extracts; Vitamin B 12; Vitamin B 12 Deficiency; Vitamin B 6; Zinc; Zinc Sulfate

We investigated the mechanism of selective ascorbate-induced cytotoxicity in tumor cells, including Hep G2 cells, compared to primary hepatocytes. H2O2 formation was required for ascorbate cytotoxicity, as extracellular catalase treatment protected tumor cells. H2O2 generated by glucose oxidase treatment also caused cell killing, but treatment with a pharmacologic dose (5-20mM) of ascorbate was significantly more cytotoxic at comparable rates of H2O2 production, suggesting that ascorbate enhanced H2O2 cytotoxicity. This was further supported by the finding that ascorbate at a non-cytotoxic dose (1mM) enhanced cell killing caused by glucose oxidase. Consistent with this conclusion, ascorbate treatment caused deregulation of cellular calcium homeostasis, resulting in massive mitochondrial calcium accumulation. Ascorbate acted synergistically with the chemotherapeutic sorafenib in killing Hep G2 cells, but not primary hepatocytes, suggesting adjuvant ascorbate treatment can broaden sorafenib's therapeutic range. Sorafenib caused mitochondrial depolarization and prevented mitochondrial calcium sequestration. Subsequent ascorbate addition further deregulated cellular calcium homeostasis promoting cell death. Additionally, we present the case of a patient with hepatocellular carcinoma (HCC) who had prolonged regression of a rib metastasis upon combination treatment with ascorbate and sorafenib, indicating that these studies have direct clinical relevance.

Topics: Apoptosis; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Proliferation; Drug Synergism; Hep G2 Cells; Humans; Hydrogen Peroxide; Liver Neoplasms; Mitochondria; Niacinamide; Phenylurea Compounds; Sorafenib

5-Azacytidine (5-AZA), a DNA methyl transferase inhibitor, is a clinically used epigenetic drug for cancer therapy. Recently, we have shown that 5-AZA upregulates ten-eleven translocation (TET) protein expression in hepatocellular carcinoma (HCC) cells, which induce active demethylation. Vitamin C facilitates TET activity and enhances active demethylation. The aim of this study is to investigate whether vitamin C is able to enhance the effect of 5-AZA on active demethylation and to evaluate its consequence in HCC cell lines.. HCC cell lines (Huh7 and HLE) were treated with 5-AZA and vitamin C. After 48 h of treatment, viability (resazurin conversion), toxicity (lactose dehydrogenase (LDH) release), and proliferation ((proliferating cell nuclear antigen (PCNA)) of single- and combined-treated cells were assessed. The effect of the treatment on 5-hydroxymethylcytosine (5hmC) intensity (immunofluorescence (IF) staining), TET, Snail, GADD45B, and P21 mRNA (real-time PCR) and protein expression (Western blot) were investigated.. Our results indicated that vitamin C enhances the anti-proliferative and apoptotic effect of 5-AZA in HCC cell lines. By further analyzing the events leading to cell cycle arrest, we have shown for the first time in HCC that the combination of 5-AZA and vitamin C leads to an enhanced downregulation of Snail expression, a key transcription factor governing epithelial-mesenchymal transition (EMT) process, and cell cycle arrest.. We conclude that when combined with 5-AZA, vitamin C enhances TET activity in HCC cells, leading to induction of active demethylation. An increase in P21 expression as a consequence of downregulation of Snail accompanied by the induction of GADD45B expression is the main mechanism leading to cell cycle arrest in HCCs.

Topics: Ascorbic Acid; Azacitidine; Carcinoma, Hepatocellular; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA Methylation; Drug Synergism; Epigenesis, Genetic; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms

We report a case of regression of multiple pulmonary metastases, which originated from hepatocellular carcinoma after treatment with intravenous administration of high-dose vitamin C. A 74-year-old woman presented to the clinic for her cancer-related symptoms such as general weakness and anorexia. After undergoing initial transarterial chemoembolization (TACE), local recurrence with multiple pulmonary metastases was found. She refused further conventional therapy, including sorafenib tosylate (Nexavar). She did receive high doses of vitamin C (70 g), which were administered into a peripheral vein twice a week for 10 months, and multiple pulmonary metastases were observed to have completely regressed. She then underwent subsequent TACE, resulting in remission of her primary hepatocellular carcinoma.

Topics: Aged; Antineoplastic Agents; Ascorbic Acid; Carcinoma, Hepatocellular; Chemoembolization, Therapeutic; Combined Modality Therapy; Female; Humans; Liver Neoplasms; Lung Neoplasms; Neoplasm Recurrence, Local; Niacinamide; Phenylurea Compounds; Sorafenib; Treatment Outcome

Owing to its ability to inactivate harmful radicals, vitamin C plays a key role in antioxidant defense. The bioavailability of this vitamin depends upon the nutritional intake and its uptake by cells, mainly through the sodium-dependent transporters SVCT1/Svct1 and SVCT2/Svct2 (human/rat). Here, we investigated the effect of liver metabolic/oxidative stress on the expression of these transporters in extrahepatic tissues.. In Zucker rats, used here as a model of liver steatosis, Svct1-2 mRNA levels were similar in obese and lean animals, except for lung tissue, where Svct2 was up-regulated. Diabetes mellitus, developed by streptozotocin administration, was accompanied by a down-regulation of Svct1 in liver and kidney, together with a down-regulation of Svct2 in kidney and brain. Complete obstructive cholestasis due to bile duct ligation for 1 week induced a significant down-regulation of both Svct1 and Svct2 in ileum, whereas Svct2 was up-regulated in liver, and no significant changes in the expression of either transporter were found in kidney, brain or lung. In rat hepatoma Can-10 cells, bile acids, but not the FXR agonist GW4064, induced an up-regulation of Svct1 and Svct2. In human hepatoma Alexander cells transfected with FXR/RXRα/OATP1B1, neither GW4064 nor unconjugated or glycine-/taurine-conjugated major bile acids were able to up-regulate either SVCT1 or SVCT2.. Pathological circumstances characterized by the presence of metabolic/oxidative stress in the liver induce different responses in the expression of ascorbic acid transporters in intrahepatic and extrahepatic tissues, which may affect the overall bioavailability and cellular uptake of this vitamin.

Topics: Animals; Ascorbic Acid; Bile Acids and Salts; Biological Availability; Carcinoma, Hepatocellular; Cell Line, Tumor; Cholestasis; Diabetes Mellitus, Experimental; Disease Models, Animal; Fatty Liver; Gene Expression; Humans; Kidney; Liver; Liver Neoplasms; Male; Obesity; Oxidation-Reduction; Oxidative Stress; Rats; Rats, Zucker; RNA, Messenger; Sodium-Coupled Vitamin C Transporters; Stress, Physiological

Epigallocatechin-gallate (EGCG) claims a plethora of health benefits including protection against neoplastic diseases. Meanwhile, heparan-sulfate proteoglycans (HSPGs) have defensive role against tumour cell invasion. Therefore, the chemopreventive and hepatoprotective effects of EGCG were studied in hepatocellular carcinoma (HCC) in vivo and in vitro and compared with strong water soluble antioxidant, sodium ascorbate.. HCC was induced in SD rats by thioacetamide (200 mg/Kg). Some rats were treated with EGCG (20 mg/Kg) or sodium ascorbate (100 mg/Kg). Liver impairment was assessed by measuring serum α-fetoprotein and investigating liver sections stained with H/E. Hepatic HSPGs, syndecan-1 and matrix metalloproteinase-9 (MMP-9) were measured by ELISA. Gene expression of fibroblast growth factor (FGF)-2 was measured. Cell death was assessed by caspase-3 activity. In addition, all markers were measured in human hepatocellular carcinoma cell line (HepG2).. EGCG increased the animal survival and decreased both α-fetoprotein and HepG2 viability. In addition, EGCG ameliorated fibrosis and massive hepatic tissue breakdown. EGCG restored HSPGs and reduced expression of MMP-9, syndecan-1 and FGF-2 in-vivo and in-vitro. Sodium ascorbate showed significantly lower results than EGCG.. Besides antioxidant activity, other mechanisms are involved in the chemopreventive and hepatoprotective effects of EGCG including restoration of HSPGs receptors and inhibition of vascular invasion.

Topics: alpha-Fetoproteins; Animals; Antineoplastic Agents, Phytogenic; Antioxidants; Ascorbic Acid; Camellia sinensis; Carcinoma, Hepatocellular; Catechin; Fibroblast Growth Factor 2; Gene Expression; Hep G2 Cells; Heparan Sulfate Proteoglycans; Humans; Liver; Liver Neoplasms; Male; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Phytotherapy; Plant Extracts; Rats, Sprague-Dawley; Syndecan-1; Thioacetamide

Methotrexate (MTX) has been widely used for rheumatoid arthritis therapy for a long time. MTX is also used as an anticancer drug for various tumors. However, many studies have shown that high-dose MTX treatment for cancer therapy may cause liver and renal damage. Alhough the mechanisms involved in MTX-induced liver and renal damage require further research, many studies have indicated that MTX-induced cytotoxicity is associated with increases in oxidative stress and caspase activation. In order to reduce MTX-induced side-effects and increase anticancer efficiency, currently, combination treatments of low-dose MTX and other anticancer drugs are considered and applied for various tumor treatments. The present study showed that MTX induces increases in H2O2 levels and caspase-9/-3 activation leading to cell death in hepatocellular carcinoma Hep3B cells. Importantly, this study is the first to demonstrate that vitamin C can efficiently aid low-dose MTX in inducing cell death in Hep3B cells. Therefore, the present study provides a possible powerful therapeutic method for tumors using a combined treatment of vitamin C and low-dose MTX.

Topics: Antimetabolites, Antineoplastic; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Gene Expression Regulation, Neoplastic; Humans; Hydrogen Peroxide; Liver Neoplasms; Methotrexate; Oxygen

Immunotherapy has become an attractive new strategy in the treatment of cancer. The laboratory and clinical study of cancer immunotherapy is rapidly advancing. However, in the clinical setting, the results of cancer immunotherapy are mixed. We therefore contend that cancer immunotherapy should be customized to each patient individually based on their immune status and propose an integrative immunotherapy approach with second-generation group-specific component macrophage activating factor (GcMAF)-containing human serum.. The standard protocol of our integrative cancer immunotherapy is as follows: i) 0.5 ml GcMAF-containing human serum is administered intramuscularly or subcutaneously once or twice per week for the duration of cancer therapy until all cancer cells are eradicated; ii) hyper T/natural killer (NK) cell therapy is given once per week for six weeks; iii) high-dose vitamin C is administered intravenously twice per week; iv) alpha lipoic acid (600 mg) is administered orally daily; v) vitamin D3 (5,000-10,000 IU) is administered orally daily.. By March 2013, Saisei Mirai have treated over 345 patients with GcMAF. Among them we here present the cases of three patients for whom our integrative immunotherapy was remarkably effective.. The results of our integrative immunotherapy seem hopeful. We also plan to conduct a comparative clinical study.>

Topics: Aged; Ascorbic Acid; Bone Neoplasms; Cell- and Tissue-Based Therapy; Combined Modality Therapy; Female; Humans; Immunotherapy; Injections, Intramuscular; Injections, Subcutaneous; Liver Neoplasms; Lung Neoplasms; Macrophage-Activating Factors; Male; Prognosis; Prostatic Neoplasms; Thioctic Acid; Thymus Neoplasms; Vitamin D-Binding Protein

The radioisotope iodine-131 [(131)I] can damage DNA. One way to prevent this is to increase the amount of antioxidants via dietary consumption. The goal of this study was to evaluate the radioprotective effect of fresh acerola pulp and synthetic beta-carotene in Rattus norvegicus hepatoma cells (HTC) in response to [(131)I] exposure in vitro. Cellular DNA damage was subsequently assessed using a cytokinesis block micronucleus assay. The mutagenic and cytotoxic activities of doses of [(131)I] (0.1, 0.5, 1, 5, and 10 µCi), acerola (0.025, 0.125, and 0.25 g acerola pulp/mL), and beta-carotene (0.2, 1, and 2 µM) were evaluated. Radioprotective tests were performed by simultaneous treatment with acerola (0.25 g/mL) plus [(131)I] (10 µCi) and beta-carotene (0.2 µM) plus [(131)I] (10 µCi). Acerola, beta-carotene, and low concentrations of [(131)I] did not induce micronucleus formation in HTC cells; in contrast, high concentrations of [(131)I] (10 µCi) were mutagenic and induced DNA damage. Moreover, neither acerola nor beta-carotene treatment was cytotoxic. However, acerola reduced the percentage of [(131)I]-induced damage, although beta-carotene did not show a similar effect. Thus, our results suggest that acerola diet supplementation may benefit patients who are exposed to [(131)I] during thyroid diagnostics and therapy.

Topics: Animals; Anthocyanins; Antioxidants; Ascorbic Acid; beta Carotene; Carcinoma, Hepatocellular; Carotenoids; Dietary Supplements; DNA; DNA Damage; Flavonoids; Iodine Radioisotopes; Liver Neoplasms; Malpighiaceae; Mutation; Plant Preparations; Radiation-Protective Agents; Rats; Rats, Wistar; Tumor Cells, Cultured

Although there is in vivo evidence suggesting a role for glutathione in the metabolism and tissue distribution of vitamin C, no connection with the vitamin C transport systems has been reported. We show here that disruption of glutathione metabolism with buthionine-(S,R)-sulfoximine (BSO) produced a sustained blockade of ascorbic acid transport in rat hepatocytes and rat hepatoma cells. Rat hepatocytes expressed the Na(+)-coupled ascorbic acid transporter-1 (SVCT1), while hepatoma cells expressed the transporters SVCT1 and SVCT2. BSO-treated rat hepatoma cells showed a two order of magnitude decrease in SVCT1 and SVCT2 mRNA levels, undetectable SVCT1 and SVCT2 protein expression, and lacked the capacity to transport ascorbic acid, effects that were fully reversible on glutathione repletion. Interestingly, although SVCT1 mRNA levels remained unchanged in rat hepatocytes made glutathione deficient by in vivo BSO treatment, SVCT1 protein was absent from the plasma membrane and the cells lacked the capacity to transport ascorbic acid. The specificity of the BSO treatment was indicated by the finding that transport of oxidized vitamin C (dehydroascorbic acid) and glucose transporter expression were unaffected by BSO treatment. Moreover, glutathione depletion failed to affect ascorbic acid transport, and SVCT1 and SVCT2 expression in human hepatoma cells. Therefore, our data indicate an essential role for glutathione in controlling vitamin C metabolism in rat hepatocytes and rat hepatoma cells, two cell types capable of synthesizing ascorbic acid, by regulating the expression and subcellular localization of the transporters involved in the acquisition of ascorbic acid from extracellular sources, an effect not observed in human cells incapable of synthesizing ascorbic acid.

Topics: Animals; Ascorbic Acid; Base Sequence; Buthionine Sulfoximine; Carcinoma, Hepatocellular; DNA Primers; Glutathione; Hepatocytes; Humans; Immunohistochemistry; Liver Neoplasms; Rats; Rats, Sprague-Dawley; Sodium-Coupled Vitamin C Transporters

Epidemiologic studies on the relationship between vitamin intake and liver cancer risk are sparse and inconsistent.. We evaluated vitamin intake from diet and supplements and risk of liver cancer in 132,837 women and men from China who were recruited into the Shanghai Women's Health Study from 1997 to 2000 or the Shanghai Men's Health Study from 2002 to 2006. In-person interviews, using a validated food-frequency questionnaire, were conducted to collect data on dietary habits. Follow-up consisted of in-person surveys and record linkage. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazard models with adjustment for potential confounders to compare liver cancer risk among participants with high vs low vitamin intake. All statistical tests were two-sided.. After excluding the first 2 years of follow-up, 267 participants (including 118 women and 149 men) developed liver cancer during an average of 10.9 (Shanghai Women's Health Study) or 5.5 (Shanghai Men's Health Study) years of follow-up. Dietary vitamin E intake was inversely associated with liver cancer risk (P(trend) = .01), as was vitamin E supplement use (hazard ratio = 0.52, 95% confidence interval = 0.30 to 0.90). This association was consistent among participants with and without self-reported liver disease or a family history of liver cancer. Vitamin C and multivitamin use was associated with increased risk among participants with self-reported liver disease or family history of liver cancer, whereas intake of vitamin C and other vitamins from dietary sources was unrelated to liver cancer risk.. Vitamin E intake, either from diet or supplements, may reduce the risk of liver cancer.

Topics: Adult; Aged; Antioxidants; Ascorbic Acid; Calcium Compounds; China; Cohort Studies; Dietary Supplements; Feeding Behavior; Female; Humans; Liver Neoplasms; Male; Middle Aged; Odds Ratio; Proportional Hazards Models; Prospective Studies; Surveys and Questionnaires; Vitamin E; Vitamins

Recent studies have demonstrated that vegetable rich diets have protective effects on the occurrence and prognosis of various cancers. In addition to dietary intakes, ascorbic acid and β-carotene are also taken as supplements. The aim of this study was to assess effects of ascorbic acid, β-carotene and their combinations on human hepatocellular carcinoma cell line HepG2. Ascorbic acid and β-carotene were applied to cells as plasma peak concentrations (70 and 8 μM, respectively) and their half concentrations (35 and 4 μM, respectively) for 24 and 48 h. Genotoxic and cytotoxic effects of ascorbic acid and β-carotene were evaluated by alkali single cell gel electrophoresis (SCGE), acridine orange/ethidium bromide staining patterns of cells (apoptosis and necrosis) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Results of the SCGE demonstrated that both ascorbic acid and β-carotene caused DNA damage on HepG2 which were also concordant to increased apoptosis and necrosis of cells. Increased TBARS values also demonstrated increased lipid peroxidation in these cells. Results of the present study demonstrates that when dietary intakes of ascorbic acid and β-carotene and their relevant achievable plasma level concentrations were considered, both ascorbic acid and β-carotene induce genotoxic and cytotoxic damage on HepG2 together with increased oxidative damage in contrast to their protective effect on healthy cells. This may be correlated to oxidative status and balance of ROS in hepatocellular carcinoma cells.

Topics: Acridine Orange; Apoptosis; Ascorbic Acid; beta Carotene; Carcinoma, Hepatocellular; Cell Line, Tumor; Comet Assay; DNA Damage; Ethidium; Genome, Human; Hep G2 Cells; Humans; Lipid Peroxidation; Liver Neoplasms; Necrosis; Staining and Labeling; Thiobarbituric Acid Reactive Substances

Diabetes mellitus (DM) is a risk factor for hepatocellular carcinoma (HCC). It directs glucose to sorbitol and fructose in polyol pathway (PP). To pursue contribution of PP in hepatocarcinogenesis.. We utilized ascorbic acid (AA) and diallyl sulfide (DAS) in experimental DM and HCC against control. HCC was induced by diethyl nitrosamine (DENA, one intraperitoneal (IP) dose 125 mg/kg), DM, by streptozotocin (STZ, IP dose 65 mg/kg). AA was given as 7.4 g/kg/d, I.P., DAS 200mg/kg/d, orally. All animals were killed after 10 weeks.. DENA elevated serum AFP, erythrocyte sorbitol (ES), neoplastic changes in liver, lowered blood glucose, increased hepatocyte aldose reductase (AR) and sorbitol dehydrogenase (SDH), significantly alleviated by DAS/AA combination. DM elevated ES activating AR, inhibiting SDH, improved by DAS and AA.. Co-induction of DM and HCC increased liver tissue lesion, serum AFP, ES, liver AR and SDH. Co-administration of DAS/AA reduced ES, AR without changing SDH. DAS/AA co-therapy lowered ES by depressing AR without affecting SDH, meaning that AR is activated by cancer and DM in different ways. PP is early marker for HCC detection and response to chemoprevention. DAS/AA combination is promising cost effective chemopreventive and anti-diabetic combination.

Topics: Aldehyde Reductase; Allyl Compounds; alpha-Fetoproteins; Animals; Ascorbic Acid; Blood Glucose; Carcinoma, Hepatocellular; Diabetes Mellitus, Experimental; Diethylnitrosamine; L-Iditol 2-Dehydrogenase; Liver; Liver Neoplasms; Male; Polymers; Rats; Rats, Wistar; Sorbitol; Sulfides

Previous epidemiologic studies that have examined the relationship between renal cell carcinoma (RCC) risk and intakes of plant foods and antioxidant nutrients have yielded inconsistent results. We therefore examined the associations between intakes of fruit, vegetables, carotenoids, flavonoids, vitamin E and vitamin C and RCC risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study cohort. At baseline, 27,062 male Finnish smokers aged 50-69 years completed a 276-item dietary questionnaire that included questions on frequency of consumption and portion size. During up to 19 years of follow-up, 255 men developed RCC. Cox proportional hazards models were utilized to estimate relative risks (RR) and 95% confidence intervals (CI). Despite a large range in intake, no association was observed between fruit, vegetables or antioxidant nutrients and RCC risk. For example, multivariate RRs and 95% CIs for the highest versus the lowest quartile of intake were 0.79 (0.55-1.14), 1.23 (0.85-1.79), 1.09 (0.74-1.60), 0.83 (0.57-1.21), 1.09 (0.73-1.64) and 0.99 (0.67-1.46) for fruit, vegetables, total carotenoids, total flavonoids, total vitamin E and vitamin C, respectively (all p values for trend > 0.05). Our results indicate that diet may not play a large role in the etiology of RCC in male smokers, although further examination of these associations in nonsmokers, women and diverse racial populations is warranted.

Topics: Aged; Antioxidants; Ascorbic Acid; Carcinoma, Renal Cell; Carotenoids; Diet; Finland; Flavonoids; Fruit; Humans; Liver Neoplasms; Male; Middle Aged; Multivariate Analysis; Prospective Studies; Risk Factors; Smoking; Surveys and Questionnaires; Vegetables; Vitamin E

The human sodium-dependent vitamin C transporter-2 (hSVCT2) plays an important role in cellular accumulation of ascorbic acid in liver cells. However, little is known about the molecular determinants that direct hSVCT2 to the cell surface in hepatocytes. We addressed this issue using live cell imaging methods to resolve the distribution and trafficking of truncated or mutated hSVCT2 constructs in a cellular model of human hepatocytes, HepG2 cells. Whereas a full-length hSVCT2-yellow fluorescent protein (YFP) fusion protein was functionally expressed at the cell surface in HepG2 cells, serial truncation and mutation analysis demonstrated an essential role for both NH(2)- and COOH-terminal sequence(s) for cell surface expression and function. Video-rate confocal imaging showed evidence of dynamic hSVCT2-YFP containing intracellular trafficking vesicles, the motility of which was impaired following disruption of microtubules using nocodazole. However, in a HepG2 cell line stably expressing hSVCT2-YFP at the cell surface, plasma membrane levels of hSVCT2 were unaffected by inhibition of microtubule-associated motor proteins; rather, surface expression of hSVCT2-YFP was increased following treatment with myosin inhibitors. Together, these results show that 1) both NH(2)- and COOH-terminal sequences are essential for proper localization of hSVCT2, 2) cell surface delivery is dependent on intact microtubules, and 3) peripheral microfilaments regulate insertion and retrieval of hSVCT2 into the plasma membrane.

Topics: Ascorbic Acid; Bacterial Proteins; Carbon Radioisotopes; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Membrane; Gene Expression; Hepatocytes; Humans; Liver Neoplasms; Luminescent Proteins; Membrane Proteins; Molecular Motor Proteins; Mutagenesis; Organic Anion Transporters, Sodium-Dependent; Protein Structure, Tertiary; Protein Transport; Sodium-Coupled Vitamin C Transporters; Symporters; Transfection

This study was to investigate whether ascorbic acid (AA) at pharmacologic concentration became prooxidant and had the potential to influence the expressions of angiogenic and angiostatic chemokine genes in hepatocellular carcinoma (HCC) cell lines. Influence of low (1 mM) and high (30 mM) pharmacologic concentrations of AA on two HCC cell lines (cell line A, HCC24/KMUH; cell line B, HCC38/KMUH) were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Three angiogenic genes (CCL2, CXCL6, IL8), one angiostatic gene (CXCL10) and two genes related to oxidative stress (SOD2, VNN3) were selected for quantitative RT-PCR study. Both low and high pharmacologic concentrations of AA up-regulated CCL2, CXCL6, IL8, SOD2 and VNN3 genes in cell line A, but down-regulated CCL2 and IL8 genes in cell line B. CXCL6 gene in cell line B was down-regulated by high pharmacologic concentration of AA. CXCL10 gene was up-regulated by low pharmacologic concentration of AA, but was down-regulated by high pharmacologic concentration of AA in both cell lines. Low pharmacologic concentration of AA up-regulated VNN3 gene and high pharmacologic concentration of AA up-regulated SOD2 gene in cell line B. These results indicate that pharmacologic concentration of AA becomes prooxidant to HCC cells and has diverse influence on differential expressions of angiogenic chemokine genes in different HCC cell lines. Differential expressions of CXCL10 gene are determined by the concentrations of AA used. Clinical application of AA in patients with HCC should consider these effects.

Topics: Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Line, Tumor; Chemokine CXCL10; Chemokines; Dose-Response Relationship, Drug; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Neovascularization, Pathologic; Oxidative Stress; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; Up-Regulation

Nitrites are ubiquitous environmental contaminants present in drinking water and foods. Nitrosamines can be formed endogenously from nitrate and nitrite and secondary amines or may be present in food, tobacco smoke, and drinking water. The major goal of this work was to evaluate the cytotoxic, reactive oxygen species (ROS)-producing and genotoxic effects of nitrite and nitrosamines and the possible protection by ascorbic acid in HepG2 cells. It was found that nitrite, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosomorpholine (NMOR) decreased cell viability, increased intracellular ROS production, and caused genotoxicity. Compared to untreated cells as determined by alkaline Comet assay, nitrite, NDMA, NDEA, and NMOR raised the tail intensity up to 1.18-, 3.79-, 4.24-, and 4.16-fold, respectively. Ascorbic acid (AA, 10 microM) increased cell viability and reduced ROS production significantly (p < 0.05). Additionally, AA treatment decreased the tail intensity caused by nitrite, NDMA, NDEA, and NMOR to 33.74%, 58.6%, 44.32%, and 43.97%, respectively. It can be concluded that ascorbic acid was able to reduce both tail intensity and tail moment in all of the nitrosamine treatments, particularly in NDMA. AA protected HepG2 cells against genotoxic effects caused by nitrosamines. This protection might be through different mechanisms, some of which are not still understood in depth. The future interest will be to understand which pathways are influenced by antioxidants, particularly by AA, and the outcomes of this prevention in other cell line types.

Topics: Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Survival; Comet Assay; Cytoprotection; Diethylnitrosamine; Dimethylnitrosamine; DNA Damage; Dose-Response Relationship, Drug; Hep G2 Cells; Humans; Liver Neoplasms; Mutagens; Nitrites; Nitrosamines; Oxidative Stress; Reactive Oxygen Species; Time Factors

Long-term survival of patients with hepatocellular carcinoma (HCC), a common cancer worldwide, remains poor, due to metastasis and recurrence.. To investigate the effect of a novel nutrient mixture (NM) containing ascorbic acid, lysine, proline, and green tea extract on human HCC cell line Sk-Hep-1 In vivo and In vitro.. After one week of isolation, 5-6 week old male athymic nude mice were inoculated with 3 x 10(6) SK-Hep-1 cells subcutaneously and randomly divided into two groups; group A was fed a regular diet and group B a regular diet supplemented with 0.5% NM. Four weeks later, the mice were sacrificed and their tumors were excised, weighed and processed for histology. We also tested the effect of NM In vitro on SK-Hep-1 cells, measuring cell proliferation by MTT assay, invasion through Matrigel, apoptosis by green caspase detection kit, MMP secretion by zymography, and morphology by H&E staining.. NM inhibited tumor weight and burden of SK-Hep-1 xenografts by 42% and 33% respectively. In vitro , NM exhibited 33% toxicity over the control at 500 and 1,000 microg/ml concentration. Zymography demonstrated MMP-2 and MMP-9 secretion which was inhibited by NM in a dose dependent fashion, with virtual total inhibition at 1000 microg/ml. Invasion through Matrigel was inhibited at 100, 500 and 1,000 microg/ml by 53%, 83% and 100% respectively. NM induced slight apoptosis at 100 microg/ml, and profound apoptosis at 500 microg/ml and 1000 microg/ml concentration.. These results suggest that NM has therapeutic potential in treatment of HCC.

Topics: Animals; Antineoplastic Agents; Apoptosis; Ascorbic Acid; Camellia sinensis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Dietary Supplements; Humans; Liver Neoplasms; Lysine; Male; Matrix Metalloproteinases; Mice; Mice, Nude; Neoplasms, Experimental; Plant Extracts; Proline; Tea; Xenograft Model Antitumor Assays

Ascorbic acid (AA) has been reported to inhibit tumor cell growth through the generation of extracellular hydrogen peroxide (H(2)O(2)). However, the clinical utility of AA has been limited by relatively low potency and in vivo efficacy. This study reports that the metalloporphyrin, Mn(III) tetrakis(N-methylpyridinium-2-yl)porphyrin(5+) (MnTMPyP), has a potent synergistic cytotoxic effect when combined with AA in a variety of cancer cell lines. In the presence of MnTMPyP, the concentration of AA required to inhibit cancer cell growth was markedly reduced. In vitro (cell-free) experiments demonstrated that AA alone enhanced the Fenton reaction that produces cytotoxic hydroxyl radical (HO(*)); however, this reaction was limited by the low rate by which AA generates H(2)O(2) (Fenton reaction substrate) from O(2). MnTMPyP catalyzed H(2)O(2) generation through the AA-facilitated Mn(II <--> III)TMPyP redox cycle and thereby markedly potentiated the Fenton reaction. Accordingly, MnTMPyP and AA resulted in increased cellular levels of H(2)O(2) and HO(*) in cancer cells, which mediate the synergistic cytotoxicity of this combined treatment. This effect was inhibited by cellular enzymes that metabolize H(2)O(2), such as catalase and glutathione peroxidase, suggesting that selective killing of cancer cells deficient in such enzymes can be achieved in vivo.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Blotting, Western; Catalase; Cell Proliferation; Drug Synergism; Glutathione; Glutathione Reductase; Humans; Hydrogen Peroxide; Hydroxyl Radical; Liver Neoplasms; Male; Manganese; Membrane Potential, Mitochondrial; Metalloporphyrins; Neoplasms, Hormone-Dependent; Oxidation-Reduction; Pancreatic Neoplasms; Prostatic Neoplasms; Reactive Oxygen Species; Superoxides; Tumor Cells, Cultured

In a population-based prospective study of 19,998 Japanese individuals, consumption of vegetables, green-yellow and green leafy vegetables was inversely associated with the risk of hepatocellular carcinoma (101 cases), with multivariable hazard ratios for the highest vs lowest tertile of 0.61 (95% confidence interval (CI)=0.36-1.03, P(trend)=0.07), 0.65 (95% CI=0.39-1.08, P(trend)=0.06) and 0.59 (95% CI=0.35-1.01, P(trend)=0.04), respectively.

Topics: Adult; Aged; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cohort Studies; Female; Fruit; Humans; Liver Neoplasms; Male; Middle Aged; Prospective Studies; Risk; Vegetables

The aim of this work was to determine the effect of vitamin C, diallyl disulfide (DADS) and dipropyl disulfide (DPDS) towards N-nitrosopiperidine (NPIP) and N-nitrosodibutylamine (NDBA)-induced apoptosis in human leukemia (HL-60) and hepatoma (HepG2) cell lines using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. None of the vitamin C (5-50 microm), DADS and DPDS (1-5 microm) concentrations selected induced a significant percentage of apoptosis. In simultaneous treatments, vitamin C, DADS and DPDS reduced the apoptosis induced by NPIP and NDBA in HL-60 and HepG2 cells (around 70% of reduction). We also investigated its scavenging activities towards reactive oxygen species (ROS) produced by NPIP and NDBA using 2',7'-dichlorodihydrofluorescein diacetate in both cell lines. ROS production induced by both N-nitrosamine was reduced to control levels by vitamin C (5-50 microm) in a dose-dependent manner. However, DADS (5 microm) increased ROS levels induced by NPIP and NDBA in HL-60 (40 and 20% increase, respectively) and HepG2 cells (18% increase), whereas DPDS was more efficient scavenger of ROS at the lowest concentration (1 microm) in both HL-60 (52 and 25% reduction, respectively) and HepG2 cells (24% reduction). The data demonstrated that the scavenging ability of vitamin C and DPDS could contribute to inhibition of the NPIP- and NDBA-induced apoptosis. However, more than one mechanism, such as inhibition of phase I and/or induction of phase II enzymes, could be implicated in the protective effect of dietary antioxidants towards NPIP- and NDBA-induced apoptosis in HL-60 and HepG2 cells.

Topics: Allyl Compounds; Antioxidants; Apoptosis; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Culture Techniques; Dietary Supplements; Disulfides; Dose-Response Relationship, Drug; HL-60 Cells; Humans; In Situ Nick-End Labeling; Leukemia, Promyelocytic, Acute; Liver Neoplasms; Nitrosamines; Oxidative Stress; Reactive Oxygen Species

Excess reactive oxygen species related to neoplasia of liver has been established. Essentially, the human body has developed different antioxidant systems for defence against these attacks. To evaluate the redox status in hepatocellular carcinoma (HCC) induced by hepatitis B virus (HBV), the most important aetiological factor in Taiwan, changes in O2(.) generation, lipid peroxidation as well as antioxidant status in the blood of HCC patients with HBV carriers for more than 20 years were measured.. Superoxide anion radical (O2(.-)) generation and the levels of malondialdehyde (MDA) served as an index of lipid peroxidation along with the analyses of activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRx); also, glutathione status, including reduced glutathione (GSH) and oxidized glutathione (GSSG), and the levels of vitamins A, C and E were determined.. In 54 patients, the levels of O2(.-), MDA and GSSG, and the activities of SOD and GRx of blood were significantly higher than those of 57 controls. Conversely, the levels of GSH and total GSH, and GSH/GSSG ratio, and vitamins A and C were significantly decreased. Additionally, there were no significant changes in the activity of GPx and the levels of vitamin E.. Our data suggest that the redox statuses in patients with HBV-associated HCC were elevated or decreased in certain parameters. However, the increased activities of antioxidant enzymes may be a compensatory up-regulation and the decrease antioxidant statuses were responses to the enhanced oxidative stress in those patients.

Topics: Adult; Aged; Aged, 80 and over; Ascorbic Acid; Carcinoma, Hepatocellular; Female; Glutathione; Glutathione Disulfide; Glutathione Peroxidase; Glutathione Reductase; Hepatitis B; Hepatitis B virus; Humans; Liver Neoplasms; Male; Malondialdehyde; Middle Aged; Oxidation-Reduction; Superoxide Dismutase; Vitamin A; Vitamin E

Because the Wnt/beta-catenin pathway plays multiple roles in liver pathobiology, it is critical to identify gene targets that mediate such diverse effects. Here we report a novel role of beta-catenin in controlling ascorbic acid biosynthesis in murine liver through regulation of expression of regucalcin or senescence marker protein 30 and L-gulonolactone oxidase. Reverse transcription-PCR, Western blotting, and immunohistochemistry demonstrate decreased regucalcin expression in beta-catenin-null livers and greater expression in beta-catenin overexpressing transgenic livers, HepG2 hepatoma cells (contain constitutively active beta-catenin), regenerating livers, and in hepatocellular cancer tissues that exhibit beta-catenin activation. Interestingly, coprecipitation and immunofluorescence studies also demonstrate an association of beta-catenin and regucalcin. Luciferase reporter and chromatin immunoprecipitation assays verified a functional TCF-4-binding site located between -163 and -157 (CTTTGCA) on the regucalcin promoter to be critical for regulation by beta-catenin. Significantly lower serum ascorbate levels were observed in beta-catenin knock-out mice secondary to decreased expression of regucalcin and also of L-gulonolactone oxidase, the penultimate and last (also rate-limiting) steps in the synthesis of ascorbic acid, respectively. These mice also show enhanced basal hepatocyte apoptosis. To test if ascorbate deficiency secondary to beta-catenin loss and regucalcin decrease was contributing to apoptosis, beta-catenin-null hepatocytes or regucalcin small interfering RNA-transfected HepG2 cells were cultured, which exhibited significant apoptosis that was alleviated by the addition of ascorbic acid. Thus, through regucalcin and L-gulonolactone oxidase expression, beta-catenin regulates vitamin C biosynthesis in murine liver, which in turn may be one of the mechanisms contributing to the role of beta-catenin in cell survival.

Topics: Animals; Antioxidants; Ascorbic Acid; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; beta Catenin; Calcium-Binding Proteins; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Survival; DNA-Binding Proteins; Gene Expression Regulation; Hepatocytes; Humans; Intracellular Signaling Peptides and Proteins; L-Gulonolactone Oxidase; Liver; Liver Neoplasms; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Promoter Regions, Genetic; RNA, Small Interfering; Transcription Factor 4; Transcription Factors

Senescence Marker Protein-30 (SMP30) is an androgen-independent factor that decreases with aging. We recently characterized SMP30 as a gluconolactonase (GNL) involved in the biosynthetic pathway of vitamin C and established that SMP30 knockout mice could not synthesize vitamin C in vivo. Although mice normally synthesize vitamin C, humans are prevented from doing so by mutations that have altered the gluconolactone oxidase gene during evolution. Even the SMP30/GNL present abundantly in the human liver does not synthesize vitamin C in vivo. To clarify the functions of this SMP30/GNL, we transfected the human SMP30/GNL gene into the human liver carcinoma cell line, Hep G2. The resulting Hep G2/SMP30 cells expressed approximately 10.9-fold more SMP30/GNL than Hep G2/pcDNA3 mock-transfected control cells. Examination of SMP30/GNL's impact on the state of oxidative stress in these cells revealed that formation of the reactive oxygen species (ROS) of mitochondrial and post-mitochondrial fractions from Hep G2/SMP30 cells decreased by a significant 24.0% and 18.1%, respectively, compared to those from Hep G2/pcDNA3 cells. Lipid peroxidation levels in Hep G2/SMP30 cells similarly decreased. Moreover, levels of the antioxidants superoxide dismutase (SOD) and glutathione (GSH) in Hep G2/SMP30 cells were a significant 42.6% and 62.4% lower than those in Hep G2/pcDNA3 cells, respectively. Thus, over-expression of SMP30/GNL in Hep G2 cells contributed to a decrease of ROS formation accompanied by decreases of lipid peroxidation, SOD activity and GSH levels.

Topics: Aging; Animals; Antioxidants; Ascorbic Acid; Calcium-Binding Proteins; Carboxylic Ester Hydrolases; Carcinoma, Hepatocellular; Gene Expression; Glutathione; Hep G2 Cells; Humans; Intracellular Signaling Peptides and Proteins; Lipid Peroxidation; Liver; Liver Neoplasms; Mice; Mice, Knockout; Mitochondria; Oxidative Stress; Reactive Oxygen Species; Superoxide Dismutase; Transfection

The effects of CO2 in the storage atmosphere on color, firmness, ascorbic acid (AA), anthocyanins, flavonoids, phenolics, total antioxidant activity, and antiproliferative activity of strawberry fruit have been investigated. "Northeaster" and "Earliglow" strawberries were stored in air or in 20% CO2 (in air) at 3 degrees C for 20 d. Color changes in Northeaster were delayed more by CO2 treatment than in Earliglow. Firmness of CO2-stored fruit increased slightly compared with those stored in air. The increases in total and reduced AA concentrations during air storage were usually prevented by CO2 storage in both cultivars. Dehydroascorbic acid (DHA) concentrations increased during CO2 storage. Anthocyanins and flavonoids, and total antioxidant activity of both cultivars were higher in air-stored fruit than in CO2-stored fruit. The total phenolic concentration was lower in CO2-stored Earliglow fruit than in air, but storage treatment did not affect that of Northeaster. A 40 mg/mL concentration of Northeaster strawberry extract inhibited about 80% of HepG2 human liver cancer cell proliferation. CO2 treatment did not affect the antiproliferative activity of strawberry fruits, but antiproliferative activity was greater at harvest than after storage.

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Carbon Dioxide; Carcinoma, Hepatocellular; Cell Division; Color; Flavonoids; Food Packaging; Food Preservation; Fragaria; Fruit; Humans; Hydroxybenzoates; Liver Neoplasms; Plant Extracts; Temperature; Time Factors; Tumor Cells, Cultured

The aim of this study was to investigate the protective effect of isothiocyanates alone or in combination with vitamin C towards N-nitrosodibutylamine (NDBA) or N-nitrosopiperidine (NPIP)-induced oxidative DNA damage in the single cell gel electrophoresis (SCGE)/HepG2 assay. Phenethyl isothiocyanate (PEITC) and indole-3-carbinol (I3C) alone showed a weak protective effect towards NDBA (0.1 microm, 26-27%, respectively) or NPIP (1 microm, 26-28%, respectively)-induced oxidative DNA damage. Allyl isothiocyanate (AITC) alone did not attenuate the genotoxic effect provoked by NDBA or NPIP. In contrast, HepG2 cells simultaneously treated with PEITC, I3C and AITC in combination with vitamin C showed a stronger inhibition of oxidative DNA-damage induced by NDBA (0.1 microm, 67%, 42%, 32%, respectively) or NPIP (1 microm, 50%, 73%, 63%, respectively) than isothiocyanates (ITCs) alone. One feasible mechanism by which ITCs alone or in combination with vitamin C exert their protective effects towards N-nitrosamine-induced oxidative DNA damage could be by the inhibition of their cytochrome P450 dependent bioactivation. PEITC and I3C strongly inhibited the p-nitrophenol hydroxylation (CYP2E1) activity (0.1 microm, 66-50%, respectively), while the coumarin hydroxylase (CYP2A6) activity was slightly reduced (0.1 microm, 25-37%, respectively). However, the ethoxyresorufin O-deethylation (CYP1A1) activity was only inhibited by PEITC (1 microm, 55%). The results indicate that PEITC and I3C alone or PEITC, I3C and AITC in combination with vitamin C protects human-derived cells against the oxidative DNA damaging effects of NDBA and NPIP, two food carcinogenic compounds.

Topics: Anticarcinogenic Agents; Aryl Hydrocarbon Hydroxylases; Ascorbic Acid; Carcinogens; Carcinoma, Hepatocellular; Cell Line, Tumor; Comet Assay; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP2A6; Cytochrome P-450 CYP2E1; Cytochrome P-450 CYP2E1 Inhibitors; DNA Breaks; DNA-Formamidopyrimidine Glycosylase; Dose-Response Relationship, Drug; Enzyme Inhibitors; Humans; Indoles; Isothiocyanates; Liver Neoplasms; Microsomes, Liver; Mixed Function Oxygenases; Nitrosamines; Oxidative Stress

Hereditary tyrosinemia type 1 (HT1) is a recessive disease caused by a deficiency of the enzyme fumarylacetoacetate hydrolase (FAH) that catalyzes the conversion of fumarylacetoacetate (FAA) into fumarate and acetoacetate. In mice models of HT1, FAH deficiency causes death within the first 24h after birth. Administration of 2-(2-nitro-4-trifluoro-methylbenzoyl)-1,3 cyclohexanedione (NTBC) prevents neonatal death in HT1 mice, ameliorates the HT1 phenotype but does not prevent development of hepatocellular carcinoma later on. FAA has been shown to deplete cells of glutathione by forming adducts. We tested whether a combination of a cell membrane permeable derivative of glutathione, glutathione monoethylester (GSH-MEE) and vitamin C could provide an alternative effective treatment for HT1. GSH-MEE (10 mmol/kg/j)/vitamin C (0.5 mmol/kg/j) treatment was given orally to pregnant/nursing female mice. While FAH-/- pups died in absence of treatment, all FAH-/- pups survived the critical first 24h of life when the mothers were on the GSH-MEE/vitamin C treatment and showed normal growth until postnatal day 10 (P10). However, after P10, pups showed failure to thrive, lethargy and died around P17. Thus, GSH-MEE/vitamin C supplementation could rescue the mice model of HT1 from neonatal death but it did not prevent the appearance of a HT1 phenotype in the second week after birth.

Topics: Animals; Animals, Newborn; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cyclohexanones; Disease Models, Animal; Drug Therapy, Combination; Female; Glutathione; Hydrolases; Liver Neoplasms; Mice; Mice, Knockout; Nitrobenzoates; Oxidative Stress; Pregnancy; Tyrosinemias

Benzotriazole derivatives have been shown to be able to induce growth inhibition in cancer cells. In the present study, we synthesized bioactive compound, 3-(1H-benzo [d] [1,2,3] triazol-1-yl)-1-(4-methoxyphenyl)-1-oxopropan-2-yl benzoate (BmOB), which is a novel benzotriazole derivative. BmOB displayed anti-proliferative effects on several human tumor cell lines. Human hepatocarcinoma BEL-7402 cell line was selected as a model to illustrate BmOB's inhibition effect and its potential mechanism, since it was the highest susceptible cell line to BmOB. It was shown that treatment with BmOB resulted in generation of reactive oxygen species, disruption of mitochondrial membrane potential (DeltaPsim), and cell death in BEL-7402 cells. BmOB induced cytotoxicity could be prevented by antioxidant vitamin C and mitochondrial permeability transition inhibitor cyclosporine A. cyclosporine A could also protect the BmOB induced collapse of DeltaPsim in BEL7402 cells, while vitamin C did not show similar effects. The results suggest that BmOB could inhibit BEL-7402 cell proliferation, and the cell death may occur through the modulation of mitochondrial functions regulated by reactive oxygen species. It appears that collapse of DeltaPsim prior to intracellular reactive oxygen species arose during the cytotoxic process in our experimental system.

Topics: Antineoplastic Agents; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Death; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclosporine; Dose-Response Relationship, Drug; Humans; Inhibitory Concentration 50; Liver Neoplasms; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Oxidative Stress; Reactive Oxygen Species; Time Factors; Triazoles

The aim of this study was to evaluate the effect of vitamin C towards N-nitrosopyrrolidine (NPYR)- and N-nitrosodimethylamine (NDMA)-induced apoptosis in human hepatoma (HepG2) and leukemia (HL-60) cell lines using flow cytometry analysis and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay (TUNEL). None of the vitamin C concentrations tested (1-100 microM) caused cytotoxicity in HepG2 cells. However, there were significant losses of HL-60 cells viability, measured by MTT assay, 72 h after treatment with 50 and 100 microM vitamin C (29 and 46%, respectively). Moreover, an increase of lactate dehydrogenase release was significant with 50 microM at 72 h (28%) and with 100 microM of vitamin C at 48 and 72 h (27 and 36%, respectively). Also, the percentage of apoptotic HL-60 cells found in TUNEL assay increased to 21% when they were treated with 100 microM vitamin C for 72 h. Thus, in subsequent simultaneous treatments with NPYR (30 and 50 mM) or NDMA (27 and 68 mM) and vitamin C, concentrations of 5-50 microM vitamin C were used. Our results revealed that vitamin C, at all concentrations and times tested, reduced the apoptosis induced by NPYR and NDMA in both cell lines, showing a similar effect in HepG2 and HL-60 cells towards NPYR (50 mM)--65 and 63% of reduction, respectively--whereas towards NDMA (27 mM) the inhibition was higher in HL-60 than in HepG2 cells--75 and 57%, respectively. Therefore, our findings suggest that inhibition of apoptosis may be one of the mechanisms by which vitamin C exerts its protective effect.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Carcinogens; Cell Line, Tumor; Cell Survival; Cytochrome P-450 Enzyme System; Excitatory Amino Acid Agonists; HL-60 Cells; Humans; In Situ Nick-End Labeling; L-Lactate Dehydrogenase; Liver Neoplasms; N-Methylaspartate; N-Nitrosopyrrolidine; Nitrosamines; Tetrazolium Salts; Thiazoles

Alpha-lipoic acid (alpha-LA) is an antioxidant used for the treatment of a variety of diseases, including liver cirrhosis, heavy metal poisoining, and diabetic polyneuropathy. In addition to its protective effect against oxidative stress, alpha-LA induces apoptosis in different cancer cells types. However, whether alpha-LA acid induces apoptosis of hepatoma cells is unknown. Herein, we investigated whether alpha-LA induces apoptosis in two different hepatoma cell lines FaO and HepG2. The results showed that alpha-LA inhibits the growth of both cell lines as indicated by the reduction in cell number, the reduced expression of cyclin A and the increased levels of the cyclin/CDKs inhibitors, p27(Kip1) and p21(Cip1). Cell cycle arrest was associated with cell loss, and DNA laddering indicative of apoptosis. Apoptosis was preceded by increased generation of reactive oxygen species, and associated with p53 activation, increased expression of Bax, release of cytochrome c from mitochondria, caspases activation, decreased levels of survivin, induction of pro-apoptotic signaling (i.e JNK) and inhibition of anti-apoptotic signaling (i.e. PKB/Akt) pathways. In conclusion, this study provides evidence that alpha-LA induces apoptosis in hepatoma cells, describes a possible sequence of molecular events underlying its lethal effect, and suggests that it may prove useful in liver cancer therapy.

Topics: Acetylcysteine; Animals; Antioxidants; Apoptosis; Ascorbic Acid; bcl-2-Associated X Protein; Carcinoma, Hepatocellular; Caspases; Cell Cycle; Cell Line, Tumor; Cell Survival; Cytochromes c; DNA Fragmentation; Enzyme Activation; Humans; Liver Neoplasms; MAP Kinase Kinase 4; Proto-Oncogene Proteins c-akt; Rats; Reactive Oxygen Species; Thioctic Acid; Tumor Suppressor Protein p53

The present study was designed to determine the possible pathway underlying the enhancement of apoptosis induced by the combined use of arsenic trioxide (As(2)O(3)) and ascorbic acid (AA).. The level of intracellular reactive oxygen species (ROS) was detected by means of flow cytometry analysis with an oxidation-sensitive fluorescent probe (6-carboxy-2',7' dichlorodihydrofluorescein diacetate) uploading. The activity of glutathione (GSH), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were detected by biochemical methods. The mitochondrial membrane potential was measured by flow cytometry analysis with rhodamine 123 staining. Bcl-2, Bax, and p17 subunit of caspase-3 were analyzed using the Western blot method. The apoptosis rate was determined by flow cytometry with annexin-V/propidium iodide staining.. Compared with As(2)O(3) (2.0 micromol/L) treated alone, As(2)O(3) (2.0 micromol/L) in combination with AA (100 micromol/L) decreased intracellular GSH content from 101.30+/-5.76 to 81.91+/-3.12 mg/g protein, and increased ROS level from 127.61+/-5.12 to 152.60+/-5.88, which was represented by the 2, 7-dichlorofluorescein intensity. The loss of mitochondria membrane potential was increased from 1269.97+/-36.11 to 1540.52+/-52.63, which was presented by fluorescence intensity. The p17 subunit of caspase-3 expression was increased approximately 2-fold. However, SOD and GPx depletion and the ratio of Bcl-2 to Bax were equal to that of As2O3 treated alone (P>0.05). When the ROS scavenger, N-acetyl-L-cysteine, was added to As(2)O(3) and AA combined treatment group, the apoptosis rate decreased from 15.60 %+/-1.14% to 9.48%+/-0.67%, and the ROS level decreased from 152.60+/-5.88 to 102.77+/-10.25.. AA potentiated As(2)O(3)-induced apoptosis through the oxidative pathway by increasing the ROS level. This may be the result of depleting intracellular GSH. It may influence the downstream cascade following ROS, including mitochondria depolarization and caspase-3 activation. However, SOD and GPx depletion and the ratio of Bcl-2 to Bax influenced by As(2)O(3) was not found to be potentiated by AA.

Topics: Acetylcysteine; Antineoplastic Agents; Antioxidants; Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; bcl-2-Associated X Protein; Carcinoma, Hepatocellular; Cell Line, Tumor; Drug Synergism; Free Radical Scavengers; Humans; Liver Neoplasms; Oxidative Stress; Oxides; Proto-Oncogene Proteins c-bcl-2

The objective of this study was to investigate the separate and combined effects of antioxidants, trichostatin A (TSA) and their combination on the in vitro cytotoxicity of Ni2+ in human hepatoma cells. Cell viability, lactate dehydrogenase (LDH) release, and DNA fragmentation were measured as indicators of cell damage. Reactive oxygen species (ROS) generation and histone acetylation were also measured. The cytotoxicity of Ni2+ increased in a time- and dose-dependent manner. In the presence of 2 mM Ni2+, ROS generation increased 365% (p<0.05), while histone acetylation decreased 37% (p<0.05). Although antioxidants, ascorbic acid (AA, 0.5 or 1 mM), reduced glutathione (GSH, 100 or 200 microM) and N-acetyl-cysteine (NAC, 0.5 or 1 mM) strongly inhibited ROS generation, their effect on Ni2+-caused histone hypoacetylation was not so obvious. On the contrary, TSA (100 nM) showed no inhibition on ROS generation but significantly increased histone acetylation in both control and Ni2+-exposed cells. As expected, the combination of antioxidants and TSA possessed the activity of both diminishing ROS generation and increasing histone hypoacetylation caused by Ni2+. Further studies found that both antioxidants and TSA could diminish the cytotoxicity of Ni2+, and their combined effects obviously improved each of their protection roles, indicating that both ROS generation and histone hypoacetylation are involved in the cytotoxicity of Ni2+, and the combination of antioxidants and TSA may act as a useful strategy to protect against this cytotoxicity.

Topics: Acetylation; Acetylcysteine; Antioxidants; Apoptosis; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Survival; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Inhibitors; Glutathione; Hepatocytes; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Liver Neoplasms; Nickel; Reactive Oxygen Species

Antioxidative vitamins are known to inhibit metastasis. Therefore we evaluated the impact of vitamins A (retinol), C (ascorbic acid) and E (alpha-tocopherol) on liver metastasis in a model of ductal pancreatic adenocarcinoma in hamster.. One hundred and twenty male Syrian hamsters were randomized into 8 groups (Gr.) (n = 15). Gr. 1-4 were given 0.5 ml normal saline subcutaneously (s.c.) weekly, whereas Gr. 5-8 received 10 mg N-nitrosobis(2-oxopropyl)amine (BOP)/kg body weight s.c. for 3 months for tumor induction. In the 13th week Gr. 2 and 6 were administered retinol, Gr. 3 and 7 received ascorbic acid and Gr. 4 and 8 were given alpha-tocopherol orally. No treatment was performed in Gr. 1 and 5. After 24 weeks animals were sacrificed, pancreas and liver were histologically determined. Activities of glutathione-peroxidase (GSH-Px), superoxide dismutase (SOD) and concentration of thiobarbituric-acid-reactive substances (TBARS) were analyzed in hepatic tissue.. Retinol and alpha-tocopherol decreased the incidence of liver metastases (44.4 vs. 86.7%, p < 0.05). The number and size of liver metastases were significantly reduced by retinol. Activities of GSH-Px and SOD were increased and concentration of TBARS was decreased in NML and LiMe by all vitamins.. Obviously, antioxidative vitamins prevent oxidative stress in hepatocytes. This may be one mechanism decreasing liver metastasis in pancreatic cancer in the present trial.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Antioxidants; Ascorbic Acid; Carcinoma, Pancreatic Ductal; Cricetinae; Disease Models, Animal; Glutathione Peroxidase; Lipid Peroxidation; Liver Neoplasms; Male; Mesocricetus; Neoplasm Metastasis; Nitrosamines; Pancreatic Neoplasms; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Vitamin A; Vitamin E

Hepatocarcinoma cells (TLT) were incubated in the presence of ascorbate and menadione, either alone or in combination. Cell death was only observed when such compounds were added simultaneously, most probably due to hydrogen peroxide (H2O2) generated by ascorbate-driven menadione redox cycling. TLT cells were particularly sensitive to such an oxidative stress due to its poor antioxidant status. DNA strand breaks were induced by this association but this process did not correspond to oligosomal DNA fragmentation (a hallmark of cell death by apoptosis). Neither caspase-3-like DEVDase activity, nor processing of procaspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP) were observed in the presence of ascorbate and menadione. Cell death induced by such an association was actively dependent on protein phosphorylation since it was totally prevented by preincubating cells with sodium orthovanadate, a tyrosine phosphatase inhibitor. Finally, while H2O2, when administered as a bolus, strongly enhances a constitutive basal NF-kappaB activity in TLT cells, their incubation in the presence of ascorbate and menadione results in a total abolition of such a constitutive activity.

Topics: Animals; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Caspase 3; Caspases; Cell Death; Liver Neoplasms; Mice; Oxidation-Reduction; Oxidative Stress; Time Factors; Vitamin K 3

Nitric oxide (NO) modifies the functions of a variety of proteins containing cysteine thiols or transition-metal centers, particularly by S-nitrosylation. In inflamed liver, NO is overproduced and hepatic drug-metabolizing enzymes, the flavin-containing monooxygenases (FMOs) and cytochrome P450s (CYPs), are suppressed. However, the NO-related mechanisms underlying the loss of these activities are not well understood, particularly for FMOs. In this study, we suggest that FMO3, the major FMO in human liver, is modified post-translationally by NO. This hypothesis is based on the imbalance observed between the decrease in FMO3 expression (40.7% of controls) and FMO3-specific ranitidine N-oxidation activity (15.1%), and on the partial or complete reversibility of FMO inhibition by sulfhydryl-reducing regents such as DTT (effective on both S-S and S-NO adducts) and ascorbate (effective on S-NO only). Furthermore, NO donors (SNP, SNAP, and Sin-1), including the pure NO donor DEA/NO, directly suppressed in vitro FMO activity (N- or S-oxidation of ranitidine, trimethylamine, and thiobenzamide) in human liver microsomal proteins and recombinant human FMO3. These activities were restored completely after treatment with DTT or ascorbate. These results suggest that NO-mediated S-nitrosylation is involved in the rigorous inhibition of FMO activity in vitro and in vivo, resulting in the suppression of FMO-based drug metabolism or detoxification.

Topics: Adult; Ascorbic Acid; Carcinoma, Hepatocellular; Dithiothreitol; Enzyme Inhibitors; Hepatitis B, Chronic; Humans; Liver; Liver Cirrhosis; Liver Neoplasms; Methylamines; Microsomes, Liver; Middle Aged; Nitric Oxide; Nitric Oxide Donors; Nitrosation; Oxygenases; Ranitidine; Recombinant Proteins; Thioamides

In this experiment, we examine the functional property of carotenoids; beta-cryptoxanthin (Cry), zeaxanthin (Zea), beta-carotene (Car)) and ascorbic acid (AsA). The accumulation amounts of Cry, Zea and Car in HepG2 cells cultured in the high concentration medium were larger than that in a low concentration. Further those accumulation amounts in long incubation time within 24 hours were greater than that in a shorter time. When the added carotenoid concentration, with or without hydrogen peroxide, increased from 0 to 5 microM in the culture medium, the thiobarbituric acid reaction substance (TBARS) values in the HepG2 cells decreased significantly (p < 0.05). The decrease of TBARS values shows the antioxidative property of the carotenoids. When AsA and Tocopherol(Toc) were added to the medium from 0 to 20 microM, the TBARS values, with or without hydrogen peroxide, decreased significantly with increasing concentrations of AsA and Toc respectively (p < 0.05). The decreased amount of TBARS in 5 microM Cry compared with control(0 microM) was the largest among 6 antioxidants (Cry, Car, Zea, Retinol(Ret), AsA, Toc) used in this experiment.

Topics: alpha-Tocopherol; Antioxidants; Ascorbic Acid; Biological Transport; Carcinoma, Hepatocellular; Carotenoids; Cell Line, Tumor; Diospyros; Humans; Japan; Lipid Peroxidation; Liver Neoplasms; Plant Extracts; Thiobarbituric Acid Reactive Substances; Vitamin A

Although ascorbate (vitamin C) has been shown to have anti-cancer actions, its effect on human hepatoma cells has not yet been investigated, and thus, the exact mechanism of this action is not fully understood. In this study, the mechanism by which ascorbate induces apoptosis using HepG2 human hepatoblastoma cells is investigated. Ascorbate induced apoptotic cell death in a dose-dependent manner in the cells, was assessed through flow cytometric analysis. Contrary to expectation, ascorbate did not alter the cellular redox status, and treatment with antioxidants (N-acetyl cysteine and N,N-diphenyl-p-phenylenediamine) had no influence on the ascorbate-induced apoptosis. However, ascorbate induced a rapid and sustained increase in intracellular Ca2+ concentration. EGTA, an extracellular Ca2+ chelator did not significantly alter the ascorbate-induced intracellular Ca2+ increase and apoptosis, whereas dantrolene, an intracellular Ca2+ release blocker, completely blocked these actions of ascorbate. In addition, phospholipase C (PLC) inhibitors (U-73122 and manoalide) significantly suppressed the intracellular Ca2+ release and apoptosis induced by ascorbate. Collectively, these results suggest that ascorbate induced apoptosis without changes in the cellular redox status in HepG2 cells, and that the PLC-coupled intracellular Ca2+ release mechanism may mediate ascorbate-induced apoptosis.

Topics: Apoptosis; Ascorbic Acid; Calcium Signaling; Carcinoma, Hepatocellular; Cell Line, Tumor; Dose-Response Relationship, Drug; Humans; Intracellular Fluid; Liver Neoplasms

A mixture of (-)-epigallocatechin-3-gallate (EGCG) and ascorbic acid exhibited 73.2% inhibition of SMMC-7721 cell proliferation in a soft agar colony formation assay, which was much higher than EGCG (40.4%) or ascorbic acid (12.4%) alone. In the cell migration assay, the mixture also significantly suppressed the migration of SMMC-7721 cells by 65.9% while EGCG and/or ascorbic acid did by 28.9% and 18.7%, respectively. Ascorbic acid was able to enhance the antioxidant activity of EGCG by decreasing the intracellular oxidative stress according to fluorographic analysis of oxidative stress. In conclusion, the combination of EGCG and ascorbic acid can strongly suppress the proliferation and metastasis of liver cancer cells, possibly with a mechanism associated with the scavenging of reactive oxygen species. All these events add to our knowledge of liver cancer chemotherapy.

Topics: Antioxidants; Ascorbic Acid; Catechin; Cell Division; Cell Movement; Colony Count, Microbial; Culture Media; Drug Therapy, Combination; Humans; Liver Neoplasms; Reference Values; Sensitivity and Specificity; Tumor Cells, Cultured

The mechanisms of redifferentiation and growth inhibition induced in human hepatoma cells by ascorbic acid (AA) were studied. After treatment with AA, the content of hydrogen peroxide (H2O2) and the activity of superoxide dismutase (SOD) increased in a concentration- and time-dependent manner, while the activity of catalase (CAT) decreased in a concentration- and time-dependent manner. Using 6 mM AA as a positive control, after treatment by 50 microM hydrogen peroxide, the malignant characteristics of human hepatoma cells were alleviated; for example as cell surface charge markedly decreased, the electrophoresis rate dropped from 1.68 microns.s-1.V-1.cm-1 to 0.97, the average of alpha-fetoprotein content decreased from 327 micrograms.g-1 protein to 193, and gamma-glutamyl-transpeptidase activity fell from 0.84 U.g-1 protein to 0.30. The indexes related to cell differentiation were promoted, such as tyrosine-alpha-ketoglutarate transaminase activity increased from 17.1 mumol.g-1 protein to 33.1, and the colonogenic potential decreased by 79.3%. SOD and 3-amino-1,2,4-triazole (AT) exhibited some effects, but there were statistically significant differences between the SOD, AT and H2O2 or AA groups. AA induced growth inhibition and redifferentiation of human hepatoma cells through the production of hydrogen peroxide, since addition of SOD (200 units/ml), an enzyme that dismutates superoxide and generates hydrogen peroxide, and AT (1.5 mM), a CAT inhibitor that inhibits the activity of CAT and leads to an increase in H2O2 content, showed some inducing changes emphasizing the involvement of reactive oxygen species (ROS) in redifferentiation of hepatoma cells. AA can cause the content of H2O2 to increase, and the factor H2O2 showed a similar effect to AA on growth and redifferentiation suggests that H2O2 is involved in hepatoma cell redifferentiation. In conclusion, these results suggest that AA inhibits tumor growth and induces tumor redifferentiation by virtue of producing H2O2.

Topics: alpha-Fetoproteins; Amitrole; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Differentiation; Cell Division; Comet Assay; Enzyme Inhibitors; gamma-Glutamyltransferase; Humans; Hydrogen Peroxide; Liver Neoplasms; Malondialdehyde; Superoxide Dismutase; Tumor Cells, Cultured; Tyrosine Transaminase

Saponins from various plant sources have been suggested as possible anticarcinogens. Major dietary sources of saponins include legumes such as soybeans. This study was performed to determine the effect of soybean saponins on aflatoxin B(1)(AFB(1))-induced mutagenicity and AFB(1)-DNA adduct formation using Salmonella typhimurium and human liver hepatoma (HepG2) cells, respectively. Major antioxidants including L-ascorbic acid, alpha-tocopherol, all-trans-retinol, and butylated hydroxytoluene (BHT), previously reported to possess antimutagenic activity, were used as test materials to evaluate the relative effectiveness of saponins. Results indicated antimutagenicity was in the order of BHT > saponins > alpha-tocopherol > L-ascorbic acid. Soybean saponins exerted a significant effect, inhibiting the mutagenicity of AFB(1) by 52%, 64%, and 81% at concentrations of 600, 900, and 1,200 microg per plate, respectively. The amount of tritiated AFB(1) metabolites-DNA adducts formed in HepG2 cells was significantly reduced when cells were preincubated with 10 or 30 microg/ml of test materials. Soybean saponins inhibited AFB(1)-DNA adduct formation by 50.1% at a concentration of 30 microg/ml, whereas L-ascorbic acid and BHT reduced adduct formation by 38.4% and 32.6%, respectively, at the same concentrations. These results indicate that soybean saponins possess not only a significant antimutagenic activity but a strong inhibitory action against carcinogen-induced DNA damages. Soybean saponins possibly block the initiation stage of carcinogenesis, and further studies are required to elucidate the mechanisms of action.

Topics: Aflatoxin B1; alpha-Tocopherol; Anticarcinogenic Agents; Antioxidants; Ascorbic Acid; Butylated Hydroxytoluene; Carcinoma, Hepatocellular; DNA Adducts; Dose-Response Relationship, Drug; Glycine max; Humans; Liver Neoplasms; Mutagenicity Tests; Mutagens; Mutation; Saponins; Treatment Outcome; Tumor Cells, Cultured

After being treated with ascorbic acid (AA) 3 mM + sodium selenite (SS) 1.5 microM, the growth rate and mitotic index of human hepatoma cells BEL-7402 decreased remarkably. The indexes related to cell malignancy were improved, such as cell surface charge obviously decreased, the electrophoresis rate fell from 1.76 microns.s-1.V-1.cm-1 to 0.93, the average of alpha-fetoprotein (alpha-FP) content decreased from 341 micrograms.g-1 protein to 92, and gamma-glutamyl-transpeptidase (gamma-GT) activity from 0.76 U.g-1 protein to 0.19. The indexes related to cell differentiation were affected favourably, such as the level of tyrosine-alpha-ketoglutarate transaminase (TAT) activity increased from 14.2 mumol.g-1 protein to 49.0, and the colonogenic potential decreased 95.3%. These results indicated that hepatoma cells had been successfully induced to redifferentiation by AA + SS. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were significantly higher, while the activity of catalase (CAT) was slower in the treated group than in the control group. The malondialdehyde (MDA) content decreased slightly, reduced glutathione (GSH) decreased sharply, and H2O2 content increased dramatically. In conclusion, these results indicate that the combination of ascorbic acid and sodium selenite may induce the redifferentiation of hepatoma cells and inhibit cell growth by virtue of enhancing the activities of antioxidative enzymes and reducing the formation of H2O2, and altering the cell redox status. The combination of ascorbic acid and sodium selenite may be a potent anticancer treatment option for human hepatoma cells.

Topics: Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Catalase; Cell Differentiation; Cell Division; Cell Survival; Electrophysiology; Glutathione; Glutathione Peroxidase; Humans; Hydrogen Peroxide; Liver Neoplasms; Malondialdehyde; Mitotic Index; Reactive Oxygen Species; Sodium Selenite; Superoxide Dismutase; Tumor Cells, Cultured

To examine the effects of ascorbic acid (AA) and DL-alpha-tocopherol (alpha T) on the proliferation and redifferentiation of human hepatoma cell.. Choosing an all-trans retinoic acid (RA) as a positive control, cell surface charge, biochemical changes, and cell growth in soft agar were measured.. After treatment with AA 4 mmol.L-1 and alpha T 1 mmol.L-1 together, the growth curve and mitotic index of human hepatoma cells decreased remarkably, the cellular growth inhibitory rate amounted to 61.3%. The indices related to cell malignancy alleviated significantly; cell surface charge decreased, the electrophoresis rate dropped from 1.64 to 0.89 microns.s-1.V-1.cm-1, the average value of alpha-fetoprotein (alpha-FP) content decreased from 300 to 80 micrograms.g-1 (protein), and gamma-glutamyl-transpeptidase (gamma-GT) activity decreased from 0.81 to 0.201 U.g-1(protein). The index related to cell differentiation increased significantly, such as the average level of tyrosine-alpha-ketoglutarate transaminase activity increased from 10.6 to 45 micrograms.g-1 (protein), and the colonogenic potential decreased by 96.6%.. AA and alpha T combination inhibited human hepatoma cell proliferation, induced redifferentiation, and reversed its malignant phenotypic characteristics.

Topics: alpha-Fetoproteins; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Differentiation; Cell Division; gamma-Glutamyltransferase; Humans; Liver Neoplasms; Tumor Cells, Cultured; Vitamin E

To assess the degree of oxidative stress, we measured plasma ubiquinone-10 percentage (%CoQ-10) in total amounts of ubiquinone-10 in patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma, and in age-matched control subjects, %CoQ-10 values were 12.9 +/- 10.3 (n = 28), 10.6 +/- 6.8 (n = 28), 18.9 +/- 11.1 (n = 20), and 6.4 +/- 3.3 (n = 16), respectively, showing a significant increase in oxidative stress in patient groups as compared to control subjects. There were no differences in total amounts of ubiquinone-10 and ubiquinol-10 among the four groups. We next measured %CoQ-10 in plasmas obtained from nine patients treated with percutaneous transluminal coronary angioplasty (PTCA). Plasmas were collected when hospitalized, and at the time (0, 4, 8, 12, 16, and 20 hr, and 1, 2, 3, 4, and 7 days) after the PTCA. %CoQ-10 values before and right after PTCA were 9.9 +/- 2.8 and 11.4 +/- 2.0, respectively, reached a maximum (20-45) at 1 or 2 days later, and decreased to 7.9 +/- 2.7 at 7 days after PTCA, indicating an increase in oxidative stress in patients during coronary reperfusion.

Topics: Adult; Aged; Aged, 80 and over; Angioplasty, Balloon, Coronary; Ascorbic Acid; beta Carotene; Bilirubin; Biomarkers; Carcinoma, Hepatocellular; Carotenoids; Female; Hepatitis; Humans; Liver Cirrhosis; Liver Neoplasms; Lycopene; Male; Middle Aged; Oxidative Stress; Reference Values; Ubiquinone; Uric Acid; Vitamin E

To examine the effects of ascorbic acid (AA) on hepatoma.. Choosing an all-trans tretinoin (Tre) as a positive control, cell growth, and cell redifferentiation tests by cell surface charges, biochemical changes, and cell growth in soft agar were measured.. After being treated with AA 6 mmol.L-1, the growth curve and mitotic index of human hepatoma cells decreased remarkably, the cellular growth inhibitory rate amounted to 58.9%. The indices related with cell malignancy alleviated, such as cell surface charge obviously decreased, the electrophoresis rate dropped from 1.64 microns.s-1.V-1.cm-1 to 0.93, the average value of alpha-fetoprotein (alpha-FP) content decreased from 302 micrograms.g-1(protein) to 90, and gamma-glytamyl-transpeptidase (gamma-GT) activity from 0.81 U.g-1(protein) to 0.16. The index related with cell differentiation increased, such as the average level of tyrosine-alpha-ketoglutarate transminase activity increased from 10.3 micromol.g-1(protein) to 41.2, and the colonogenic potential decreased 94.4%.. AA can inhibit human hepatoma cells proliferation, induce redifferentiation, and reverse its malignant phenotypic characteristics.

Topics: alpha-Fetoproteins; Antineoplastic Agents; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Division; Cell Survival; Cell Transformation, Neoplastic; gamma-Glutamyltransferase; Humans; Liver Neoplasms; Mitotic Index; Tumor Cells, Cultured

We have applied our method for the simultaneous detection of plasma ubiquinol-10 (reduced form) and ubiquinone-10 (oxidized form) (S. Yamashita and Y. Yamamoto, Anal. Biochem. 250, 66-73, 1997) to plasmas of normal subjects (n = 16) and patients with chronic active hepatitis (n = 28), liver cirrhosis (n = 16), and hepatocellular carcinoma (n = 20) to evaluate the pressure of oxidative stress in these patients. The average ubiquinone-10 percentages (+/- S.D.) in total ubiquinone-10 and ubiquinol-10 in the four groups were 6.4 +/- 3.3, 12.9 +/- 10.3, 10.6 +/- 6.8, and 18.9 +/- 11.1, respectively, indicating a significant increase in ubiquinone-10 percentage in patient groups in comparison to normal subjects. These results and a significant decrease in the plasma ascorbate level in patient groups indicate that oxidative stress is evident after the onset of hepatitis and the subsequent cirrhosis and liver cancer.

Topics: Adult; Aged; Aged, 80 and over; Antioxidants; Ascorbic Acid; beta Carotene; Biomarkers; Carcinoma, Hepatocellular; Carotenoids; Cholesterol; Cholesterol Esters; Female; Hepatitis, Chronic; Humans; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Lycopene; Male; Middle Aged; Oxidative Stress; Ubiquinone; Vitamin E

Oral administration of ochratoxin A to young weanling mice (Mus musculus) caused several haematological changes and induced hepatoma and renal carcinoma. Concurrent administration of berry and leaf juice of the common grape (Vitis vinifera) to mice together with ochratoxin A significantly reduced the hepatic and renal damage caused by ingestion of this mycotoxin. None of the animals receiving berry/leaf juice of V. vinifera showed the formation of hepatorenal carcinoma whereas 25% of animals receiving only ochratoxin A developed well differentiated renal carcinoma and hepatic lesions.

Topics: Animals; Antidotes; Ascorbic Acid; Carcinogens; Carcinoma, Hepatocellular; Carcinoma, Renal Cell; Kidney Neoplasms; Liver Neoplasms; Mice; Ochratoxins; Plant Leaves; Rosales; Thiamine

Redox activities associated with plasma membranes of nonphagocytic animal and plant cells have been reported by several authors. However, the natural substrates, structure and biological role of these putative enzyme systems are not known. Data indicating extracellular reduction of a nitroxide free radical Cat1 (1-oxy-4-trimethylamine-2,2,6,6,tetramethyl-piperidine) by hepatocytes were thought to be artefactual. We report evidence in support of a notion that Cat1 as well as a tetrazolium salt, CTC (5-cyano-2,3-ditolyl tetrazolium chloride), are reduced extracellularly, probably at the cell surface, by human HepG2 hepatoma cells. These data provide evidence confirming the existence of a yet unidentified reducing activity associated with outer surface of plasma membranes of transformed human hepatocytes.

Topics: 4-Chloromercuribenzenesulfonate; Ascorbic Acid; Calcium Channels; Carcinoma, Hepatocellular; Catalase; Cell Line, Transformed; Cell Membrane; Doxorubicin; Extracellular Matrix; Free Radicals; Humans; Liver Neoplasms; NAD; Oxidation-Reduction; Tetrazoles; Tetrazolium Salts; TRPV Cation Channels

The human hepatoma cells SMMC-7721 were treated with different concentrations of ascorbic acid (50-800 mumol/L) and FeSO4 (2.5-40 mumol/L) system to generate oxidative stress at various degrees. The oxidative stress induced by the system were mainly contributed to hydroxyl radical. All the various degrees of oxidative stress in this study are able to inhibit the proliferation of hepatoma cells. While low levels of oxidative stress may cause hepatoma cells lost some malignant features, such as aggregation of Con-A to the cell surface, alpha-fetoprotein, gamma-glutamyltransepeptidase and tyrosine-alpha-ketoglutarate transaminase, all of the 4 indices tended to cell differentiation, coloning efficiency potential decreased significantly, and apoptotic cells appeared. The numbers of apoptotic cells increased with the increasing of oxidative stress. The apoptotic cells exhibited non-adherent, smaller, chromatin condensed around the periphery of the nucleus in the shape of crescent, nuclear fragmentations but with intact cellular membrane, and DNA degraded to around 21.2 kbp fragment. All of the results showed that there is possibility to inhibit hepatoma cells growth, to promote differentiation and apoptosis, and therefore to initiate reverse transformation via strict regulation of oxidative stress.

Topics: Apoptosis; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Division; Cell Transformation, Neoplastic; Free Radical Scavengers; Humans; Liver Neoplasms; Oxidative Stress; Tumor Cells, Cultured

The goal of the current study was to evaluate the effects of arachidonic acid, as a representative polyunsaturated fatty acid, on the viability of a Hep G2 cell line, which has been transduced to express human cytochrome P4502E1 (CYP2E1). Arachidonic acid produced a concentration- and time-dependent toxicity to Hep G2-MV2E1-9 cells, which express CYP2E1, but little or no toxicity was found with control Hep G2-MV-5 cells, which were infected with retrovirus lacking human CYP2E1 cDNA. In contrast to arachidonic acid, oleic acid was not toxic to the Hep G2-MV2E1-9 cells. The cytotoxicity of arachidonic acid appeared to involve a lipid peroxidation type of mechanism since toxicity was enhanced after depletion of cellular glutathione; formation of malondialdehyde and 4-hydroxy-2-nonenal was markedly elevated in the cells expressing CYP2E1, and toxicity was prevented by antioxidants such as alpha-tocopherol phosphate, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox), propylgallate, ascorbate, and diphenylphenylenediamine, and the iron chelator desferrioxamine. Transfection of the Hep G2-MV2E1-9 cells with plasmid containing CYP2E1 in the sense orientation enhanced the arachidonic acid toxicity, whereas transfection with plasmid containing CYP2E1 in the antisense orientation decreased toxicity. The CYP2E1-dependent arachidonic acid toxicity appeared to involve apoptosis, as demonstrated by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling and DNA laddering experiments. Trolox, which prevented toxicity of arachidonic acid, also prevented the apoptosis. Transfection with a plasmid containing bcl-2 resulted in complete protection against the CYP2E1-dependent arachidonic acid toxicity. It is proposed that elevated production of reactive oxygen intermediates by cells expressing CYP2E1 can cause lipid peroxidation, which subsequently promotes apoptosis and cell toxicity when the cells are enriched with polyunsaturated fatty acids such as arachidonic acid. The Hep G2-MV2E1-9 cells appear to be a valuable model to study interaction between CYP2E1, polyunsaturated fatty acids, reactive radicals, and the consequence of these interactions on cell viability and to reproduce several of the key features associated with ethanol hepatotoxicity in the intragastric infusion model of ethanol treatment.

Topics: alpha-Tocopherol; Antioxidants; Apoptosis; Ascorbic Acid; Aspirin; Carcinoma, Hepatocellular; Cell Survival; Chromans; Cytochrome P-450 CYP2E1; Deferoxamine; Humans; L-Lactate Dehydrogenase; Liver Neoplasms; Oleic Acid; Phenylenediamines; Propyl Gallate; Proto-Oncogene Proteins c-bcl-2; Recombinant Proteins; Transfection; Tumor Cells, Cultured; Vitamin E

There is evidence that the development of hepatocarcinoma in rats fed a methyl-deficient diet is associated with oxidative stress. We investigated, therefore, whether the tissue concentrations of the antioxidant vitamins ascorbic acid (AA) and alpha- and gamma-tocopherol (T) are altered in methyl/folate deficiency. We also measured retinol concentrations in tissues and hepatic mRNA expression of heme oxygenase (HO1). A 6% gelatin, 6% casein diet, devoid of choline and folate (CFD) was selected based on the high rate of tumor development in rats fed this diet. Spectrophotometric measurement of AA and HPLC determination of tissue T and retinol showed decreased concentrations of AA in blood; alpha- and gamma-T in lung, heart and plasma, alpha-T and retinol in liver; retinol in lung; and increased expression of hepatic HO1 mRNA. Similar alterations in tissue vitamin concentrations were found when the CFD diet devoid of niacin (CFND) was fed. Reducing alpha-T in the CFND diet (CFNED) further decreased hepatic alpha-T concentrations. These results show that chronic methyl/folate deficiency is associated with a compromised antioxidant defense system.

Topics: Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Choline Deficiency; Folic Acid Deficiency; Heme Oxygenase (Decyclizing); Liver Neoplasms; Male; Methionine; Niacin; Oxidative Stress; Rats; Rats, Inbred F344; Vitamin A; Vitamin E; Vitamin E Deficiency; Vitamins; Weight Gain

The enhancing effect on liver metastasis produced by the excessive surgical stress of thoraco-laparotomy (TL), and its regulation with a radical scavenger, were studied in 10-week-old Donryu rats. The rats were divided into three groups: those given thoraco-laparotomy for 1 h (the TL group); those given laparotomy alone for 1 h (the L group); those given a short laparotomy (the C group). The effects of treatment with 5 mg/kg of EPC-K1 was assessed in the TL group. A rat hepatocellular carcinoma cell line AH 60C (5 x 10(5) cells) was administered into the portal vein under general anesthesia. The number of metastatic liver nodules was counted 3 weeks later, and the lipid peroxide (LPO) levels of the liver and serum were measured by the TBA method on postoperative days (PODs) 1, 2, and 3. The number of metastatic liver nodules was 40.6 +/- 29.7, 15.0 +/- 15.8, and 13.7 +/- 9.4 in the TL, L, and C groups, respectively. When EPC-K1 was administered to the TL group, the LPO level on POD 1 decreased from 49.8 +/- 25.8 to 18.9 +/- 7.9 nM/g, and the number of metastatic liver nodules decreased from 27.2 +/- 30.0 to 8.9 +/- 12.7 in parallel. The findings of this study suggested that the excessive surgical stress produced by thoraco-laparotomy enhanced liver metastasis in parallel with an increase in LPO levels; however, the radical scavenger EPC-K1 could aid in reversing this effect.

Topics: Animals; Antioxidants; Ascorbic Acid; Carcinoma, Hepatocellular; Free Radical Scavengers; Laparotomy; Lipid Peroxides; Liver Neoplasms; Male; Mice; Neoplasm Metastasis; Oxidative Stress; Rats; Rats, Inbred Strains; Tumor Cells, Cultured; Vitamin E

To understand the role of nitric oxide (NO) in the regulation of energy metabolism of tumor cells, its effect on the respiration and calcium homeostasis was examined with ascites hepatoma (AH130) cells under different oxygen tensions. NO reversibly inhibited the respiration and depolarized the membrane potential of AH130 cells in an oxygen-dependent manner; the inhibition was more marked at physiologically low oxygen concentrations than at its high tensions. NO reversibly decreased the cellular ATP levels and elevated the cytosolic calcium, particularly under low oxygen concentrations. Since the peritoneal cavity is fairly anaerobic, the results suggested that small amounts of NO generated in this compartment might strongly affect the energy metabolism and calcium homeostasis of tumor cells in vivo.

Topics: Adenosine Triphosphate; Animals; Antimycin A; Ascites; Ascorbic Acid; Biological Transport; Calcium; Carcinoma, Hepatocellular; Electron Transport; Energy Metabolism; Erythrocytes; Hemoglobins; Liver Neoplasms; Male; Membrane Potentials; Mitochondria, Liver; Neoplasm Transplantation; Nitric Oxide; Oxygen; Oxygen Consumption; Rats; Rats, Inbred Strains; Rotenone; Succinates; Succinic Acid; Tetramethylphenylenediamine; Tumor Cells, Cultured

The study was performed to examine the effects of the lipophilic ascorbic acid, 2-O-octadecylascorbic acid (CV-3611), with a strong scavenging capacity for active oxygen species, on the spontaneous development of liver tumors in male C3H/HeNCrj mice. Animals were given a diet containing 0.1% CV-3611 for a total experimental period of 16 months. Hepatocellular carcinomas developed in 2/39 (5%) of these experimental mice and in 11/43 (26%) of control mice fed a basal diet. The numbers of carcinoma per mouse were 0.05 +/- 0.22 and 0.33 +/- 0.61 respectively. Thus, CV-3611 clearly suppressed the development of hepatocellular carcinomas. However, the scavenger did not affect either the incidence or the number of hepatocellular adenomas, suggesting that active oxygen species might be involved in the conversion of adenomas to carcinomas in spontaneous liver carcinogenesis in C3H/HeNCrj mice.

Topics: Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Drug Screening Assays, Antitumor; Free Radical Scavengers; Liver Neoplasms; Male; Mice; Mice, Inbred C3H

In animal experiments with Wistar rats we attempted to determine if oral application of Vitamin C inhibits or delays carcinogenesis due to oral administered N-Nitrosopiperidine (NTP). One group of animals received NTP only, two other groups NTP and Vitamin C either alternating or simultaneously. A fourth group receiving only Vitamin C served as control. Carcinomas of the esophagus, stomach and liver developed in response to NTP application. The additional administration of Vitamin C neither inhibited nor delayed the development of carcinomas.

Topics: Animals; Anticarcinogenic Agents; Ascorbic Acid; Carcinogens; Dose-Response Relationship, Drug; Esophageal Neoplasms; Female; Liver Neoplasms; Male; Neoplasms, Experimental; Nitrosamines; Rats; Rats, Inbred Strains; Stomach Neoplasms

Rats were treated for 1 week each with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), 0.2% N-bis(2-hydroxypropyl)-nitrosamine (DHPN) and 0.2% N-ethyl-N-hydroxyethylnitrosamine (EHEN) in the drinking water, and then administered diet containing 5% sodium L-ascorbate (Na-AsA), 1% butylated hydroxytoluene (BHT) or 0.05% phenobarbital (PB), or weekly intraperitoneal injections of 2 mg of pepleomycin per kg body weight until week 36. Histopathological examination revealed that all exerted significant modulation effects on tumor development in the various target organs. Na-AsA was found to inhibit liver but promote renal pelvis and bladder carcinogenesis. BHT similarly decreased liver and enhanced bladder lesion development. PB, in contrast promoted hepatocarcinogenesis. However both PB and BHT were associated with increased incidences of adenomas and adenocarcinomas of the thyroid. Thus the wide-spectrum initiation model allowed confirmation of site-specific modification potential and in addition demonstrated potentiation of kidney and bladder carcinogenesis promotion by pepleomycin.

Topics: Animals; Ascorbic Acid; Bleomycin; Body Weight; Butylated Hydroxytoluene; Cocarcinogenesis; Kidney Neoplasms; Liver Neoplasms; Lung Neoplasms; Male; Neoplasms, Experimental; Peplomycin; Phenobarbital; Rats; Rats, Inbred F344; Thyroid Neoplasms; Urinary Bladder Neoplasms

The influence on the survival of ascitic liver tumor (TLT)-bearing mice of combined vitamins C and K3 administered before or after a single i.p. dose of 6 different cytotoxic drugs, all commonly used in human cancer therapy, was investigated. Combined i.p. administration of these vitamins produced a distinct chemotherapy-potentiating effect for all drugs examined, especially when injected before chemotherapy. This potentiating treatment did not increase the general and organ toxicity that accompanies cancer chemotherapy. The possible generation of peroxides followed by membrane lipid alteration, DNase activation and DNA destruction by combined vitamin C and K3 in catalase-deficient cancer cells might be involved in the mechanisms of this selective potentiation.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Body Weight; Catalase; Cyclophosphamide; Deoxyribonucleases; DNA Damage; Drug Synergism; Enzyme Activation; Liver Neoplasms; Male; Mice; Organ Size; Vitamin K

Dynamics of the content of 3-OAK-A in the liver, blood and urine as well as of free and bound AK in the liver of rats and mice was traced by the quantitative precipitation reaction and oxidimetric method of ascorbic acid (AA) determination. It was shown that an increase in the content of 3-OAK-A in the liver during carcinogenesis initiation and progression is accompanied by a decrease in the AA content in this organ. One of the possible mechanisms inhibiting the formation of 3-OAK-A is "interception" of the proteins involved in the formation of 3-OAK-A.

Topics: 3-Hydroxyanthranilic Acid; Animals; Antigens; Ascorbic Acid; Liver; Liver Neoplasms; Male; Mice; o-Aminoazotoluene; ortho-Aminobenzoates; Rats

The multiple-step model of carcinogenesis discussed here identifies the two major stages of initiation and promotion. A more recent research development proposes that oncogenes present in chromosomes are activated by viral, chemical, or physical agents and cause cancer. A great variety of natural mutagens and carcinogens find their way into the modern US diet. Excessive fat and alcohol consumption have been studied in relation to many kinds of malignancies. Dietary anticarcinogens include vitamins A, C, and E, although under certain conditions some generally inhibitive substances can actually enhance carcinogenesis. A provocative hypothesis argues that a high-fiber diet can substantially reduce the likelihood of carcinoma of the colon.

Topics: Aflatoxins; Ascorbic Acid; Carcinogens; Diet; Dietary Fats; Dietary Fiber; Ethanol; Humans; Liver Neoplasms; Neoplasms; Nitrogen Oxides; Nutritional Physiological Phenomena; Oncogenes; Retinoids

Topics: Animals; Ascorbic Acid; Esophageal Neoplasms; Liver Neoplasms; Male; Rats; Rats, Inbred Strains; Riboflavin; Riboflavin Deficiency

Topics: Aged; Antineoplastic Agents; Ascorbic Acid; Drug Therapy, Combination; Female; gamma-Linolenic Acid; Humans; Linolenic Acids; Liver Neoplasms; Male; Middle Aged

Topics: Ascorbic Acid; Diet; Humans; Linolenic Acids; Liver Neoplasms

Administration to rats of ascorbate with morpholine and nitrite was previously shown to inhibit the liver tumor production and to enhance the induction of forestomach tumors, as compared to treatment with morpholine and nitrite. In a repetition of this experiment, 10 g morpholine/kg in the diet and 2 g sodium nitrite/liter in the drinking water were administered for life to male MRC-Wistar rats without (group 1) or with (group 2) 22.7 g sodium ascorbate/kg in the diet. Group 3 was untreated. Group 2 showed a lower liver tumor incidence with a longer latency than group 1, indicating a 78% inhibition by ascorbate of in vivo N-nitrosomorpholine (NMOR) formation. The incidence of forestomach papillomas was 3% in group 1, 38% in group 2, and 8% in group 3. The difference between groups 1 and 2 was not significant due to the shorter life-span of group 1. Group 1 and especially group 2 had more forestomach hyperplasia and hyperkeratosis than group 3. Ascorbate might have enhanced induction of these lesions because of an action synergistic with that of NMOR. However, it is most likely that the lowered NMOR dose and concomitantly increased survival produced by the ascorbate were solely responsible for the increased incidence of forestomach papillomas and other lesions in group 2.

Topics: Animals; Ascorbic Acid; Diet; Drug Interactions; Esophagus; Hyperplasia; Liver Neoplasms; Male; Morpholines; Nitrites; Nitrosamines; Papilloma; Rats; Sodium Nitrite; Stomach; Stomach Neoplasms; Time Factors

The effects of the antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), ethoxyquin (EQ), and sodium L-ascorbate (SA) on two stage chemical carcinogenesis were investigated in male F344 rats initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-ethyl-N-hydroxyethylnitrosamine (EHEN), N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) or N-methylnitrosourea (MNU). BHA was given in diet at a dose level of 0.5 or 2.0%, BHT at 1.0%, SA at 5.0% and EQ at 0.8% for 29-51 weeks. Complete autopsy was performed at sacrifice and organs were examined histologically for the presence of preneoplastic and neoplastic lesions. All of the antioxidants tested exerted a positive influence on the development of BBN- or MNU-initiated bladder carcinogenesis. Similarly, these chemicals tended to enhance the appearance of forestomach tumors although the data gained after BHT administration were not significant. In clear contrast, no effect was observed on glandular stomach carcinogenesis and, with the exception of SA, the antioxidants all showed inhibition of the development of preneoplastic and neoplastic lesions in the liver. EQ increased the occurrence of renal adenoma in EHEN-treated rats. Clear differences were observed with respect to the modification of thyroid carcinogenesis after MNU initiation, BHT demonstrating strong promotion activity whereas BHA and SA had no effect. Thus organ specificity, with regard to both direction of modification and to the effects of individual antioxidants was apparent, this intriguing finding offering hope for the development of future experimental approaches for elucidation of the mechanisms underlying chemical carcinogenesis.

Topics: Animals; Antioxidants; Ascorbic Acid; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Ethoxyquin; Kidney Neoplasms; Liver Neoplasms; Methylnitrosourea; Neoplasms, Experimental; Rats; Rats, Inbred F344; Stomach Neoplasms; Urinary Bladder Neoplasms

The biological mode of action of tumor promoters, exemplified by the phorbol esters, is a subject of intensive study in a number of laboratories. A few investigators have recently begun to examine the role of dietary nutrients in tumor promotion, but the available data are sparse and interpretation difficult. A few examples are provided to indicate that some nutrients may be important in the promotion of cancer. However, the fine dividing line between effects on initiation or on promotion, so clearly shown in the mouse two-stage skin cancer model, is not so clear as yet in models used for studies in nutritional carcinogenesis. The animal models for these studies have been primarily rats, mice and hamsters. These have shown that nutrients which appear to have promotion activity are zinc deficiency and 13-cis-retinoic acid for the esophagus; vitamin A deficiency and lipotrope deficiency for the forestomach, unsaturated fat and vitamin A deficiency for liver and colon, lipotrope deficiency for the liver; selenium for the liver. It is probably more correct at this early stage of investigation to consider the effects of nutrients acting either during the time of exposure to the carcinogen, or, after such exposure and when no detectable carcinogen is found in the animals tissues, rather than as promoters in the strict sense.

Topics: Animals; Ascorbic Acid; Carcinogens; Cocarcinogenesis; Colonic Neoplasms; Cricetinae; Diet; Disease Models, Animal; Esophageal Neoplasms; Gastrointestinal Neoplasms; Liver Neoplasms; Mice; Neoplasms, Experimental; Pancreatic Neoplasms; Rats; Stomach Neoplasms; Zinc

Erythrocyte transketolase (ETK), glutathione reductase (EGR) and glutamate pyruvate transaminase (EGPT) enzyme activities and coenzyme effects (in vitro coenzyme stimulation) were studied in 30 random, 10 primary hepatoma, and 3 pellagrins natives from Mozambique. Twenty-nine subjects of the random group exhibited ETK coenzyme effects below 20%. Urinary thiamine levels in this group were in normal or high ranges. The primary hepatoma group had 4 with ETK coenzyme effects above 30%, and 3 of the 4 had low level urinary thiamine excretions. Of the three pellagra patients in the study, none showed biochemical vitamin B1 deficiency. All primary hepatoma and 23 random natives had EGR coenzyme effects above 30%, but the daily urinary riboflavin excretions correlated with the coenzyme effect in only the random group. EGPT activities were spread over a wide range. The random group with high EGPT activity showed a correlation with low coenzyme effect, while the primary hepatoma group did not exhibit this correlation. After 4-day single-vitamin treatment, vitamin B1 increased total ETK and vitamin B2 increased total EGR (after in vitro coenzyme saturation). Vitamin B6 did not increase total EGPT. Vitamin B2 was less effective on total EGR in primary hepatoma than in random subjects.

Topics: Alanine Transaminase; Ascorbic Acid; Black People; Carcinoma, Hepatocellular; Erythrocytes; Glutathione Reductase; Humans; Liver Neoplasms; Male; Pellagra; Pyridoxine; Riboflavin; South Africa; Thiamine; Transketolase

Topics: 2-Acetylaminofluorene; Animals; Aryl Hydrocarbon Hydroxylases; Ascorbic Acid; Butylated Hydroxytoluene; Carcinogens; Dimethylhydrazines; Hydroxyacetylaminofluorene; In Vitro Techniques; Liver Neoplasms; Male; Methylazoxymethanol Acetate; Mutation; Neoplasms; Neoplasms, Experimental; p-Dimethylaminoazobenzene; Rats; Selenium; Sister Chromatid Exchange

Topics: Aflatoxins; Amaranth Dye; Animals; Ascorbic Acid; Azo Compounds; Cocarcinogenesis; Liver Neoplasms; Male; Rats; Vitamin A

Cells from a rat hepatoma grown in culture were found to activate methyldopa to intermediates which are bound irreversibly to cellular proteins. The binding reaction was not inhibited by superoxide dismutase or allopurinol, but was strongly inhibited by ascorbic acid and glutathione. Methyldopa, paracetamol and furosemide were not mutagenic in the Salmonella/mammalian-microsome mutagenicity test.

Topics: Acetaminophen; Allopurinol; Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Cells, Cultured; Deferoxamine; Dimethylnitrosamine; Edetic Acid; Furosemide; Glutathione; Liver Neoplasms; Maleates; Methyldopa; Neoplasms, Experimental; Protein Binding; Rats; Superoxide Dismutase; Time Factors; Xanthines

Topics: Ascorbic Acid; Carcinoma, Hepatocellular; Humans; Liver Neoplasms

Massive doses of vitamin C protected rats against liver tumour production by aminopyrine and sodium nitrite, but the protection against lung and kidney tumour production was not complete. The mechanism is in part due to blockage of in vivo nitrosation. Other unknown factors may operate to give the liver complete protection.

Topics: Adenocarcinoma; Aminopyrine; Animals; Ascorbic Acid; Liver Neoplasms; Male; Neoplasms, Experimental; Nitrites; Rats

Groups of male MRC Wistar rats were treated for 2 years either with morpholine (10 g/kg food) together with sodium nitrite (3 g/l drinking water) or with N-nitrosomorpholine (NM, 0.15g/l drinking water). In both cases, a group of rats was given sodium ascorbate (22.7 g/kg food) in addition to these treatments. When ascorbate was present, the liver tumors induced by morpholine and nitrite showed a 1.7-fold longer induction period, a slightly lower incidence, and an absence of metastases in the lungs, indicating that ascorbate had inhibited the in vivo formation of NM. Ascorbate did not affect liver tumor induction by the performed NM. The group treated with morpholine, nitrite, and ascorbate had a 54% incidence of forestomach tumors, including an 18% incidence of squamous cell carcinomas, possibly because ascorbate promoted NM action in this organ.

Topics: Animals; Ascorbic Acid; Drug Interactions; Liver Neoplasms; Male; Morpholines; Neoplasms, Experimental; Nitrites; Nitroso Compounds; Rats; Stomach Neoplasms

Topics: Animals; Ascorbic Acid; Chemical and Drug Induced Liver Injury; Female; Guinea Pigs; Liver; Liver Neoplasms; Lung; Male; Morpholines; Nitrates; Nitroso Compounds; Precancerous Conditions

Normal and tumour tissues from rats, blood from normal and tumour bearing rats, and normal human blood were examined using the electron paramagnetic resonance (epr) technique. At low temperature a triplet epr signal, which is known to be produced by a NO-haemoprotein complex, was detected in some tumour samples and in decaying normal liver. At room temperature all of the tumour samples examined gave a doublet signal. This signal was also detected in blood but not in other normal tissues. The signal has a g value of 2·0054 ± 0·0002 and a hyperfine splitting of 1·80 ± 0·05 G and is assigned to the ascorbyl free radical. Model experiments suggest that the appearance of detectable concentrations of this radical result from a disturbance of the normal state of the ascorbic acid, dehydroascorbic acid redox system. It was verified that cell division is not responsible for the ascorbyl radical although autolysis may be involved. A possible relationship between the formation of ascorbyl radicals and other paramagnetic species in tumours is discussed.

Topics: Animals; Ascorbic Acid; Autolysis; Blood Proteins; Carcinoma 256, Walker; Carcinoma, Hepatocellular; Cell Division; Electron Spin Resonance Spectroscopy; Liver Neoplasms; Lung Neoplasms; Methods; Models, Biological; Models, Chemical; Neoplasms; Nitric Oxide; Oxidation-Reduction; Rats; Sarcoma, Yoshida; Temperature

Topics: Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Cell Division; Electron Spin Resonance Spectroscopy; Glutamates; Iron; Liver Neoplasms; Malates; Mitochondria, Liver; Neoplasms, Experimental; Oxidation-Reduction; Oxidative Phosphorylation; Oxygen Consumption; Phenylenediamines; Rats; Rotenone; Succinates; Sulfur; Time Factors; Uncoupling Agents

Topics: Animals; Ascorbic Acid; Electron Spin Resonance Spectroscopy; Guinea Pigs; In Vitro Techniques; Liver; Liver Neoplasms; Lung; Male; Radiation Effects; Rats; Spleen; Testis; Thymus Gland

Topics: Animals; Ascorbic Acid; Female; Injections, Intra-Arterial; Injections, Intramuscular; Injections, Intraperitoneal; Injections, Intravenous; Iron; Kidney Neoplasms; Kinetics; Liver Neoplasms; Radionuclide Imaging; Rats; Sarcoma, Experimental; Technetium

Topics: Abdomen; Aged; Antiemetics; Ascorbic Acid; Bismuth; Carcinoma, Basal Cell; Diverticulum; Duodenal Diseases; Epididymitis; Gastrectomy; Humans; Liver Neoplasms; Male; Neoplasm Metastasis; Pain; Stomach Neoplasms; Tracheotomy

Topics: Adenine Nucleotides; Ascorbic Acid; Barbiturates; Catalysis; Chemical Phenomena; Chemistry; Hexokinase; Iron; Liver; Liver Neoplasms; Metabolism; NADP; Research; Sulfates

Topics: Alloxan; Animals; Ascorbic Acid; Carbohydrate Metabolism; Carbon Isotopes; Diabetes Mellitus, Experimental; Liver Neoplasms; Metabolism; Neoplasms, Experimental; Rats; Research

Topics: Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Dietary Fats; Fatty Acids, Essential; Glucuronates; In Vitro Techniques; Lactones; Liver; Liver Neoplasms; Microsomes; p-Dimethylaminoazobenzene; Rats; Subcellular Fractions

Topics: Adenoma, Bile Duct; Ascorbic Acid; Azo Compounds; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Carcinoma, Hepatocellular; Chemical Phenomena; Chemistry; Coloring Agents; Diet; Liver; Liver Neoplasms; Pharmacology; Rats; Research; Sulfhydryl Compounds; Trichloroacetic Acid

Topics: Animals; Ascorbic Acid; Carcinoma, Ehrlich Tumor; Carcinoma, Hepatocellular; Liver; Liver Neoplasms; Lymphoma; Lymphoma, Non-Hodgkin; Metabolism; Mice; Microsomes; Microsomes, Liver; Neoplasms; Neoplasms, Experimental; Oxidoreductases; Research

Topics: Animals; Ascorbic Acid; Carcinoma, Hepatocellular; Flavonoids; Liver Neoplasms; Mice; Neoplasms, Experimental; Rutin; Vitamins