ascorbic-acid and Leukemia--Promyelocytic--Acute

Myelodysplastic syndrome (MDS) is a heterogeneous bone marrow disorder primarily affecting older adults, for whom the only curative therapy, bone marrow transplantation, is rarely an option. New therapies, or novel applications of historical therapies, are desperately needed. Arsenic trioxide (ATO), which acts through pro-apoptotic, antiproliferative, and anti-angiogenesis mechanisms, has been used successfully to treat a variety of hematologic malignancies, including MDS. As monotherapy or in combination with other agents, it can effect hematologic improvement in 22% to 26% of patients, with tolerable side effects. MDS patients whose cells express the EVI1 mutation in particular may derive benefit from this therapy.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Cell Division; Clinical Trials as Topic; Dexamethasone; DNA-Binding Proteins; Drug Therapy, Combination; Glutathione; Hematologic Neoplasms; Humans; Leukemia, Promyelocytic, Acute; MDS1 and EVI1 Complex Locus Protein; Multicenter Studies as Topic; Myelodysplastic Syndromes; Neovascularization, Pathologic; Oxides; Proto-Oncogenes; Transcription Factors

Ascorbate is stabilized in the presence of HL-60 cells. This stabilization has been questioned as a simple chemical effect. Further properties and controls about the enzymatic nature of this stabilization are described and discussed. Our results showed that cAMP derivatives and cAMP-increasing agents stimulated the ability of HL-60 cells to stabilize ascorbate. On the other hand, tunicamycin, a glycosylation-interfering agent, inhibited this ability. These data, together with hormonal regulation, support the hypothesis of an enzymatic redox system located at the plasma membrane as being responsible for the extracellular ascorbate stabilization by HL-60 cells.

Topics: Ascorbate Oxidase; Ascorbic Acid; Cell Membrane; Chelating Agents; Cyclic AMP; Extracellular Space; Free Radicals; Humans; Hydrogen-Ion Concentration; Leukemia, Promyelocytic, Acute; NADH, NADPH Oxidoreductases; Neoplasm Proteins; Oxidation-Reduction; Temperature; Tumor Cells, Cultured

Ascorbate, an essential nutrient in humans, primates, and guinea pig, is involved in many cellular functions. Ascorbate also modulates cell growth and differentiation. Ascorbate can reduce or stimulate the growth of tumor cells, depending on the cell type. The inhibitory effect is not specific for the biological active isomer L-ascorbate, and isoascorbate and D-ascorbate are more effective in reducing cell growth than L-ascorbate. These results indicate that ascorbate has a cytotoxic effect by killing cells directly, rather a cytostatic one. However, only L-ascorbate is able to stimulate cell growth, but the mechanism of this stimulation is still unknown. L-Ascorbate stimulates the in vitro differentiation of several mesenchyme-derived cell types by altering the expression of multiple genes as the cell progresses through specific differentiation programs. Stimulation of collagen matrix at gene transcription, mRNA stabilization, hydroxylation, and secretion is a key role for L-ascorbate. L-Ascorbate also prevents cell transformation by stabilization of the differentiated state and cooperates with other agents to induce differentiation in a leukemia cell line.

Topics: Animals; Ascorbic Acid; Calcitriol; Cartilage; Cell Differentiation; Cell Division; Growth Inhibitors; Guinea Pigs; Humans; Leukemia, Promyelocytic, Acute; Mesoderm; Mice; Neoplasms; Nutritional Requirements; Oxidative Stress; Species Specificity; Tumor Cells, Cultured

Seventy-six patients with acute promyelocytic leukemia (APL) in first complete remission after induction and consolidation by daunorubicin and cytosine arabinoside received oral arsenic trioxide (As(2)O(3))-based maintenance. Three regimens were used: oral As(2)O(3) (10 mg/day, regimen A, n = 20), oral As(2)O(3) plus all-trans retinoic acid (ATRA, 45 mg/m(2) per day, regimen AA, n = 19), and oral As(2)O(3) plus ATRA plus ascorbic acid (1000 mg/day, regimen AAA, n = 37), each given for 2 weeks every 2 months for 2 years. Patients receiving A, AA, and AAA maintenance did not differ significantly in clinicopathologic features and risk factors. Headache, dyspepsia, reversible liver function derangement, and herpes zoster reactivation were adverse effects observed during maintenance. QTc prolongation and arrhythmias were not encountered. At a median follow-up of 24 months (range, 1-115 months), there were 8 relapses. The 3-year leukemia-free-survival, event-free-survival, and overall-survival were 87.7%, 83.7%, and 90.6%, respectively. Adverse prognostic factors included male gender for leukemia-free-survival, and unrelated cancers for overall survival. Age, presentation WBC count and platelet count, and the type of oral As(2)O(3) maintenance regimens had no impact on survivals. Prolonged oral As(2)O(3) maintenance was feasible and safe and resulted in favorable outcomes when used with a simple induction and consolidation regimen compared with other protocols composed of multiple chemotherapeutic agents.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Cytarabine; Daunorubicin; Disease-Free Survival; Dyspepsia; Female; Follow-Up Studies; Headache; Humans; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Oxides; Recurrence; Remission Induction; Time Factors; Treatment Outcome; Tretinoin

For patients who have acute promyelocytic leukemia (APL) in second complete remission (CR2), optimal postremission strategies remain undefined.. The role of an oral arsenic trioxide (As. Seventy-three patients with APL in first relapse (R1) were studied. Oral As. For patients with relapsed APL, As

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Ascorbic Acid; Chemical and Drug Induced Liver Injury; Combined Modality Therapy; Disease-Free Survival; Female; Headache; Hematopoietic Stem Cell Transplantation; Hong Kong; Humans; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Neoplasm Recurrence, Local; Prospective Studies; Remission Induction; Risk Factors; Severity of Illness Index; Survival Analysis; Time Factors; Transplantation, Autologous; Tretinoin; Young Adult

The use of high-dose ascorbate (ASC) for the treatment of human cancer has been attempted several decades ago and has been recently revived by several in vitro and in vivo studies in solid tumors. We tested the cytotoxic effects of ASC, alone or in combination with arsenic trioxide (ATO) in acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL). Leukemic cell lines and primary blasts from AML and APL patients were treated with graded concentrations of ASC, alone or in association with standard concentration (1 μM) of ATO. The ASC/ATO combination killed myeloid blasts, including leukemic CD34+ cells, while sparing CD34+ progenitors obtained from normal cord blood and bone marrow. Actually, approximately one-third (11/36) of primary AML cases were highly sensitive to the ASC/ATO combination. The mechanism of cell killing appeared to be related to increased oxidative stress and overproduction of ROS in a non-quantitative fashion, which resulted in induction of apoptosis. These effects were reverted by the addition of the antioxidant N-Acetyl-Cysteine (NAC). In the APL NB4 model, ASC induced direct degradation of the PML and PML/RARA proteins via caspase activation, while the transcriptional repressor DAXX was recruited in re-constituted PML nuclear bodies. Our findings encourage the design of pilot studies to explore the potential clinical benefit of ASC alone or in combination with ATO in advanced AML and APL.

Topics: Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Humans; Leukemia, Myeloid, Acute; Leukemia, Promyelocytic, Acute; Oxides; Reactive Oxygen Species; Survival Analysis; Tumor Cells, Cultured

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

Arsenic trioxide (ATO/As2O3) is a promising drug for patients with a relapse of acute promyelocytic leukemia (APL); however, it frequently causes fatal arrhythmias. This study aims to investigate the various cellular and molecular mechanisms of adverse cardiac effects and the electrophysi-ological alterations caused by As2O3. We show the dose-dependent effect of ATO (0.2, 0.4, 0.8, 1.6, 3.2, 6.4 mum) on electrically driven cardiac action potential from the papillary muscle of the guinea pig. ATO causes a significant prolongation of action potential duration (APD) at various levels of repolarization, conduction delay, and increased triangulation, which is a novel marker for the proarrhythmic potential of a compound. Electrolyte imbalance (hypomagnesemia and hypokalemia) has also been found to cause amplification of ATO toxicity. Since ion channels play a very important role in the generation of cardiac action potential, we used various ion channel modulators such as choline, minoxidil, nifedipine, and verapamil to determine whether these agents could antagonize electrophysiological alterations caused by ATO. In in vivo experiments, ATO administration to animals for 10 days caused myocardial disorganization, interstitial edema and infiltration of inflammatory cells in the heart. Efforts were also made to screen the efficacy of vitamin C against ATO toxicity. ATO also caused a significant increase in the activity of certain clinically relevant enzymes for cardiac function and antioxidant mechanismssuch as serum creatine kinase isoenzyme, lactate dehydrogenase, glutathione peroxidase and reduced glutathione. In conclusion, ATO causes significant adverse cardiac effects and we suggest that cardiac function to be monitored during treatment with ATO. Our results also indicate that the status of the body's main electrolyte content (such as magnesium and potassium) is also an influencing factor on the magnitude of toxicity of arsenic trioxide.

Topics: Action Potentials; Animals; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Dose-Response Relationship, Drug; Drug Antagonism; Edema, Cardiac; Guinea Pigs; Heart; Leukemia, Promyelocytic, Acute; Male; Membrane Transport Modulators; Myocardium; Oxidants; Oxides; Oxidoreductases; Vasodilator Agents

Curcumin (Cur), a promising anticancer drug, kills tumor cells through either diminishing or promoting reactive oxygen species (ROS) generation. In this study, it was investigated whether trichostatin A (TSA), a specific histone deacetylase (HDAC) inhibitor and a new anticancer drug, could improve the anticancer activity of low concentrations of Cur in human leukemia cells (HL-60). HL-60 cells were treated with Cur, TSA or their combinations; cell proliferation arrest, lactate dehydrogenase (LDH) release and cell viability were measured as indicators of cell damage. Reactive oxygen species (ROS) accumulation and the acetylation of histones were also measured. The cytotoxicity of Cur and TSA increased in a time and dose-dependent manner. Low Cur (no more than 20 microM) diminished the ROS generation in HL-60 cells, while high Cur (50 and 100 microM) promoted that. In contrast, TSA showed no influence on ROS generation. When their effects on histone acetylation were determined, low Cur showed no effect, while TSA significantly increased that. As expected, combinations of low Cur and TSA could not only diminish ROS generation, but also increase histone acetylation, and hence showed a more significant cytotoxicity in HL-60 cells. Since the extra ROS generation may also harm normal cells, instead of using high Cur, combining low Cur with TSA is obviously a better strategy to improve the anticancer activity of Cur.

Topics: Acetylation; Acetylcysteine; Antineoplastic Agents, Phytogenic; Antioxidants; Ascorbic Acid; Cell Line, Tumor; Cell Proliferation; Cell Survival; Curcumin; Drug Synergism; Histones; HL-60 Cells; Humans; Hydroxamic Acids; Indicators and Reagents; L-Lactate Dehydrogenase; Leukemia, Promyelocytic, Acute; Protein Synthesis Inhibitors; Reactive Oxygen Species

Beta-Lapachone a novel topoisomerase inhibitor, has been found to induce apoptosis in various human cancer cells. In this study we report that a dramatic elevation of hydrogen peroxide (H2O2) in human leukemia HL-60 cells following 1 microM beta-lapachone treatment and that this increase was effectively inhibited by treatment with antioxidant N-acetyl-L-cysteine (NAC), ascorbic acid, alpha-tocopherol. NAC strongly prevented beta-lapachone-induced apoptotic characteristics such as DNA fragmentation and apoptotic morphology. However, treatment of HL-60 cells with another topoisomerase inhibitor camptothecin (CPT) did not induce H2O2 production as compared to untreated cells. NAC also failed to block CPT-induced apoptosis. Correlated with these findings, we found that cancer cell lines K562, MCF-7, and SW620, contained high level of intracellular glutathione (GSH), were not elevated in H2O2 and were resistant to apoptosis after treatment with beta-lapachone. In contrast, cancer cell lines such as, HL-60, U937, and Molt-4 which have lower level of GSH, were readily increased of H2O2 and were sensitive to this drug. Furthermore, ectopic overexpression of Bcl-2 in HL-60 cells also attenuated beta-lapachone-induced H2O2 and conferred resistance to beta-lapachone-induced cell death. Beta-Lapachone at the concentration as low as 0.25 microM effectively induced HL-60 cells to undergo monocytic differentiation, as evidenced by CD14 antigenicity and alpha-naphthyl acetate esterase activity. Again, the beta-lapachone-induced monocytic differentiation was suppressed by NAC. These results suggest that intracellular H2O2 generation plays a crucial role in beta-lapachone-induced cell death and differentiation.

Topics: Acetylcysteine; Antioxidants; Apoptosis; Ascorbic Acid; Cell Differentiation; DNA Fragmentation; Drug Resistance; Enzyme Inhibitors; Glutathione; Humans; Hydrogen Peroxide; Leukemia, Promyelocytic, Acute; Monocytes; Naphthoquinones; Proto-Oncogene Proteins c-bcl-2; Topoisomerase I Inhibitors; Tumor Cells, Cultured; Vitamin E

The effect of ascorbate on cell growth was examined using primary cultured hepatocytes and chondrocytes elicited from guinea pigs and six kinds of cell lines derived from the tissue and blood of mammals. Cells were cultured in medium supplemented with or without ascorbate at various concentrations for 24 and 48 h. There were differences among the cells used here in the effect of ascorbate on growth, and also in the concentrations of ascorbate required to lower cell viabilities. This indicates that different cell species have varying sensitivities to ascorbate in medium. On the other hand, cells such as HL-60, which showed growth inhibition at higher concentrations of ascorbate in medium among observed cells, were damaged by the exposure to higher concentrations of hydrogen peroxide (H2O2). Furthermore, there was a positive correlation between the activity of catalase in cells that decomposed H2O2 and the concentration of ascorbate required to lower cell viability (p < 0.01). These results indicate that the concentration of ascorbate in medium required to inhibit cell growth depends on the activity of catalase in the cells.

Topics: Animals; Ascorbic Acid; Brain; Cartilage; Catalase; Cell Division; Cell Line; Cell Survival; Culture Media; Guinea Pigs; Humans; Hydrogen Peroxide; Leukemia, Promyelocytic, Acute; Liver; Mice; Rats; Spleen; Tumor Cells, Cultured

We recently reported that the concentration of supplemental ascorbate which inhibits cell growth is positively related to intracellular catalase activity. It is assumed that the cells with high catalase activity are resistant to high concentrations of ascorbate since catalase can decompose hydrogen peroxide (H2O2) induced by the auto-oxidation of ascorbate in cultured medium. In this study, we investigated whether intracellular catalase activity affects the uptake of ascorbate into animal tissue and cultured cells. Ascorbate concentrations in the tissues of guinea pigs and various cultured cells, with and without supplementation of ascorbate, were determined to evaluate the efficiency of ascorbate uptake. We found a positive correlation between the efficiency of ascorbate uptake and catalase activity in various tissues of guinea pigs (r = 0.767, p < 0.05). Furthermore, a positive correlation between the two was also found in various species of cultured cells. This study indicates that tissues and cells with higher efficiency of ascorbate uptake are required for higher catalase activity, presumably for the decomposition of H2O2 from ascorbate.

Topics: Animals; Ascorbic Acid; Biological Transport; Catalase; Cell Line; Guinea Pigs; Humans; Hydrogen Peroxide; Intestine, Small; Kidney; Leukemia, Promyelocytic, Acute; Liver; Lung; PC12 Cells; Rats; Tumor Cells, Cultured

The influence of reducing compounds on the formation of DNA--protein cross-links induced by hexavalent chromium was studied in the human cell line HL-60. Analysis of cytoplasmic concentration of ascorbic acid and glutathione by HPLC in these cells showed that ascorbic acid was not detectable (detection limit: 0.1 nmol). The cellular content of glutathione was low (6 nmol/million cells). It could easily be depleted with diethylmaleate. The effect of glutathione, ascorbic acid and ascorbyl palmitate alone, or glutathione in combination with ascorbyl palmitate was investigated. It could be shown that glutathione increased DNA--protein cross-links in HL-60 cells by chromate significantly in a dose dependent manner, while pre-incubation with L-ascorbic acid and L-ascorbic acid-6-hexadecanate (ascorbyl palmitate) did not change the cross-linking activity of chromate significantly. Ascorbyl palmitate counteracted the increasing effect of glutathione on the concentration of DNA--protein cross-links in HL-60 cells after exposure to chromate. As ascorbic acid reacts much faster with hexavalent chromium at physiological pH than glutathione does, this suggests an influence of the reaction velocity of the redox reaction between hexavalent chromium and the reducing compounds on the toxification of Cr(VI) and formation of DNA--protein cross-links.

Topics: Antimutagenic Agents; Ascorbic Acid; Biological Transport; Carcinogens, Environmental; Cell Division; Cell Line; Chromates; Chromium; DNA, Neoplasm; Dose-Response Relationship, Drug; Glutathione; Humans; Kinetics; Leukemia, Promyelocytic, Acute; Maleates; Neoplasm Proteins; Oxidation-Reduction; Tumor Cells, Cultured

The cellular accumulation of vitamin C, a substance critical to human physiology, is mediated by transporters located at the cell membrane, and is regulated in a cell-specific manner. Neoplastic cells may have special needs for vitamin C. Therefore, we investigated the transport of vitamin C in a human myeloid leukemia cell line (HL-60). The HL-60 cells lacked the capacity to transport the reduced form of vitamin C, ascorbic acid, but they showed a remarkable ability to transport the oxidized form of vitamin C, dehydroascorbic acid (DHA). Uptake-accumulation studies indicated that the HL-60 cells accumulated ascorbic acid when provided with DHA. Kinetic analysis showed the presence of two functional activities involved in the uptake of DHA, one with low affinity and one with high affinity. Cytochalasin B and phloretin, which inhibit the passage of glucose through the facilitative glucose transporters, also inhibited the transport of DHA by HL-60 cells. Transport of DHA was completed by D- but not L-hexoses, and was sensitive to D-hexose-dependent counter transport acceleration. These data support the concept that HL-60 myeloid leukemic cells transport DHA through the facilitative hexose transporters (glucose transporters) and accumulate the reduced form of ascorbic acid.

Topics: 3-O-Methylglucose; Ascorbic Acid; Biological Transport; Cell Line; Cytochalasin B; Dehydroascorbic Acid; Deoxyglucose; Glucose; Humans; Isomerism; Kinetics; Leukemia, Promyelocytic, Acute; Methylglucosides; Monosaccharide Transport Proteins; Oxidation-Reduction; Phloretin; Tumor Cells, Cultured

Electron flow across the plasma membrane of living cells and its rapid modulation by growth factors has been measured continuously through a simple assay procedure whereby the transported electrons are captured by ascorbate free radical to slow the rate of chemical oxidation of ascorbate. The assay provides a direct demonstration of electron transport to an external electron acceptor that is both physiological and impermeant. The reduction of external ascorbate free radical is stimulated by the growth factors, EGF and transferrin, and is inhibited by wheat germ agglutinin. The results demonstrate, under physiological conditions, the operation of a growth factor- and lectin-responsive electron transport system at the cell surface using a cultured human cell line.

Topics: Ascorbic Acid; Cell Membrane; Electron Transport; Growth Substances; Humans; Leukemia, Promyelocytic, Acute; Oxidation-Reduction; Tumor Cells, Cultured

Ascorbate free radical stimulates the growth of human promyelocytic leukemia cells (HL-60) in the presence of a limited amount of serum (1%) when added to the cells under conditions where it is impermeable. Maximum growth stimulation occurs at concentrations from 5 x 10(-9) to 2 x 10(-8) M. Ascorbate mimicks the stimulation effect of its free radical but stimulates at higher concentrations. Autoxidation of ascorbate by oxygen produces its free radical, which apparently causes growth stimulation. Ascorbate could be regenerated by intact cells in vitro, since prevention of autoxidation of ascorbate in the presence of cells is observed. Neither dehydroascorbate nor isoascorbate increases HL-60 cell growth. Short term incubation of cells in the presence of ascorbate free radical induced intracellular NADH oxidation. We propose that the stimulation of growth of HL-60 cells shown here could be caused by activation of the transplasma membrane electron transport system by the ascorbate free radical.

Topics: Ascorbic Acid; Free Radicals; Humans; Leukemia, Promyelocytic, Acute; NAD; Oxidation-Reduction; Tumor Cells, Cultured