ascorbic-acid and Burkitt-Lymphoma

Ascorbate is a pro-oxidant that generates hydrogen peroxide-dependent cytotoxity in cancer cells without adversely affecting normal cells. To determine the mechanistic basis for this phenotype, we selected Burkitt lymphoma cells resistant to ascorbate (JLPR cells) and their ascorbate-sensitive parental cells (JLPS cells). Compared with JLPS cells, the increased glucose uptake in JLPR cells (with upregulated glucose transporters, increased antioxidant enzyme activity, and altered cell cycling) conferred ascorbate-induced cytotoxicity and resistance. Transcriptomic profiles and function pathway analysis identified differentially expressed gene signatures for JLPR cells and JLPS cells, which differential expression levels of five genes (ATF5, CD79B, MHC, Myosin, and SAP18) in ascorbate-resistant cells were related to phosphoinositide 3 kinase, cdc42, DNA methylation and transcriptional repression, polyamine regulation, and integrin-linked kinase signaling pathways. These results suggested that coordinated changes occurred in JLPR cells to enable their survival when exposed to the cytotoxic pro-oxidant stress elicited by pharmacologic ascorbate treatment.

Topics: Activating Transcription Factors; Antioxidants; Apoptosis; Ascorbic Acid; Burkitt Lymphoma; Carrier Proteins; CD79 Antigens; Cell Line, Tumor; Cell Proliferation; Co-Repressor Proteins; Drug Resistance, Neoplasm; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Hydrogen Peroxide; Major Histocompatibility Complex; Myosins; Oxidative Stress; Phosphatidylinositol 3-Kinases; Reactive Oxygen Species; RNA-Binding Proteins; Signal Transduction; Transcriptome

Ascorbic acid has been shown to kill various cancer cell lines at pharmacologic concentrations. We found that Epstein-Barr virus (EBV)-positive Burkitt lymphoma (BL) cells were more susceptible to ascorbic acid-induced cell killing than EBV-negative BL cells or EBV-transformed lymphoblastoid cells (LCLs). Ascorbic acid did not induce apoptosis in any of the tested cells but did induce the production of reactive oxygen species and cell death. Previously, we showed that bortezomib, a proteasome inhibitor, induces cell death in LCLs and EBV-positive BL cells. We found that ascorbic acid is strongly antagonistic for bortezomib-induced cell death in LCLs and EBV-positive BL cells. Finally, ascorbic acid did not prolong survival of severe combined immunodefiency mice inoculated with LCLs either intraperitoneally or subcutaneously. Thus, while ascorbic acid was highly effective at killing EBV-positive BL cells and LCLs in vitro, it antagonized cell killing by bortezomib and was ineffective in an animal model.

Topics: Animals; Antineoplastic Agents; Apoptosis; Ascorbic Acid; Boronic Acids; Bortezomib; Burkitt Lymphoma; Cell Line, Transformed; Cell Line, Tumor; Cell Survival; Cell Transformation, Viral; Female; Herpesvirus 4, Human; Humans; Mice; Pyrazines; Reactive Oxygen Species; Virus Replication

Loss of p53 renders cells more susceptible to acute oxidant stress induced by oxidant-generating agents such as motexafin gadolinium (MGd). We hypothesized that reactive oxygen species (ROS)-generating MGd results in low-level p53 expression, making cells more susceptible to oxidant stress.. Lymphoma cells were incubated with different concentrations of MGd with or without zinc (Zn) and ascorbate, and ROS, apoptosis, proteins, and oxidant genes were measured.. MGd, with ascorbate and Zn, induced apoptosis in lymphoma cells. This was accompanied by reduction of p53 protein but not message, and by reduction of p53 downstream targets p21, glutathione peroxidase 1 (GPx1), and p53 up-regulated modulator of apoptosis (PUMA). p53 protein reduction was reversed by MG132, and nutlin-3.. Our data are consistent with a pathway of cell death that is independent of p53-mediated induction of PUMA; the cellular response to reduce p53 represents a cell survival adjustment to ROS-mediated stress.

Topics: Apoptosis; Ascorbic Acid; Burkitt Lymphoma; Cell Line, Tumor; Gene Expression; Humans; Imidazoles; Leupeptins; Lymphoma, Follicular; Metalloporphyrins; Piperazines; Proto-Oncogene Proteins c-mdm2; Reactive Oxygen Species; Tumor Suppressor Protein p53; Zinc

Non-Hodgkin lymphomas incidence has increased more than 70% in last 25 years. Aggressiveness, higher relapse rate, and treatment complications pose significant barriers. Decreased food intake and side effects of treatments make cancer patients vulnerable to deficiency of essential nutrients such as vitamin C, lysine, and proline leading to the formation of weak extra cellular matrix susceptible to easy breakdown by matrix metalloproteinase enzymes. Inhibition of these enzymes has shown promise in stopping metastasis.. In this study, we investigated the effects of a specific nutrient mixture, containing ascorbic acid, lysine, proline, green tea extract among others, in most aggressive forms of non-Hodgkin's lymphoma - Burkitt's lymphoma, and T-cell lymphoma - using Raji and Jurkat cells respectively.. Nutrient mixture (NM) doses of 0, 10, 50, 100, 500, 1000 microg/ml, were used to study effects on cell proliferation, expression of matrix metalloproteinase, Matrigel invasion and apoptosis.. The results demonstrated that the dose response toxicity of the nutrient mixture on Raji cells gradually increased with increasing concentration. The nutrient mixture was non-toxic to Jurkat cells, however exhibited anti-proliferative properties at higher concentrations. Zymography demonstrated, NM had a significant inhibitory effect on matrix metalloproteinase-9 expression with total inhibition at 1000 microg/ml for Raji cells and at 500 microg/ml for Jurkat cells. The NM at 100 microg/ml completely inhibited Matrigel invasion for Raji cells, and at 1000 microg/ml for Jurkat cells. After the NM challenge virtually all Raji and Jurkat cells exposed to 1000 microg/ml were in late apoptosis.. Considering the lack of treatment options and continually increasing incidence, NM could be further explored for its therapeutic potential in Burkitt's lymphoma and T-cell lymphoma.

Topics: Antineoplastic Agents; Apoptosis; Ascorbic Acid; Burkitt Lymphoma; Cell Proliferation; Collagen; Drug Combinations; Humans; Laminin; Lymphoma, T-Cell; Lysine; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Proline; Proteoglycans; Tea; Tumor Cells, Cultured

Topics: Acute Disease; Adult; Antigens, CD; Antineoplastic Agents; Antioxidants; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Burkitt Lymphoma; Drug Therapy, Combination; Female; Humans; L-Lactate Dehydrogenase; Leukemia, Lymphoid; Oxides; Salvage Therapy; Treatment Outcome

Human lymphoid cells (Raji) were exposed to water-soluble compounds from cigarette smoke (CS) generated in a smoking machine. DNA damage, as detected by alkaline single-cell microelectrophoresis (COMET assay), was induced in a time- and concentration-dependent manner in the cells. Most of the rapidly induced DNA damage was attributable to direct-acting compounds since cytochrome P450-related metabolic activities (ethoxy- and pentoxyresorufin-O-deethylases and coumarin-7-hydroxylase) were absent or very low. In addition, induction of DNA damage could be inhibited only slightly by beta-naphthoflavone and coumarin. Vitamin C enhanced DNA damage in Raji cells probably by redox cycling of catechol and hydroquinone present in CS implicating reactive oxygen intermediates as another source of DNA damage. N-acetylcysteine, a radical scavenger and glutathione precursor, reduced DNA damage in Raji cells when exposure to CS was followed by 2 h post-incubation in culture medium. Unrepaired DNA damage caused by CS persisted longer than gamma-irradiation-induced DNA damage. Among the CS constituents, acrolein, but not formaldehyde and acetaldehyde, induced DNA damage although less intensely than CS itself. At 50 and 100 microM concentrations, acrolein also inhibited repair of gamma- irradiation-induced DNA damage in the COMET assay. Inhibition of DNA synthesis by acrolein at 50 microM was demonstrated by an immunochemical assay for bromo-deoxyuridine incorporation; however, inhibition of a representative repair enzyme, 8-oxoguanosine hydrolase, by either CS or acrolein was not observed. The present results further confirm the presence of direct-acting genotoxic components and inhibitors of DNA repair in the gas phase of tobacco smoke, that may contribute to DNA damage and smoking-associated cancers of the upper aerodigestive tract.

Topics: Acetaldehyde; Acetylcysteine; Acrolein; Aldehydes; Aryl Hydrocarbon Hydroxylases; Ascorbic Acid; B-Lymphocytes; beta-Naphthoflavone; Biotransformation; Burkitt Lymphoma; Coumarins; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP2A6; Cytochrome P-450 CYP2B1; Cytochrome P-450 Enzyme System; DNA Damage; DNA Repair; DNA-Formamidopyrimidine Glycosylase; DNA, Neoplasm; Formaldehyde; Free Radical Scavengers; Gamma Rays; Humans; Mixed Function Oxygenases; N-Glycosyl Hydrolases; Oxidation-Reduction; Reactive Oxygen Species; Smoke