ascorbic-acid and Leukemia--Myeloid--Acute

Topics: Ascorbic Acid; Dehydroascorbic Acid; Electron Spin Resonance Spectroscopy; Erythrocytes; Free Radicals; Glutathione; Humans; Leukemia, Lymphoid; Leukemia, Myeloid, Acute; Oxidation-Reduction; Potassium; Sodium

Arsenic trioxide (ATO) is highly effective in acute promyelocytic leukemia (APL), but despite its multiple mechanism of action, it has no activity in acute myeloid leukemia (AML) that excludes APL (non-APL AML). Ascorbic acid (AA) and ATO induces apoptosis in AML cell lines by depleting intracellular glutathione and generation of reactive oxygen species. In this study, we evaluated the effect of ATO plus AA in patients with non-APL AML. The study enrolled patient aged 18 or older with relapsed or refractory AML (non-APL) after conventional chemotherapy or previously untreated patients 55 years or older who were unfit for standard induction chemotherapy for AML. Intravenous ATO (0.25 mg/kg/day over 1-4 h) was given with intravenous AA (1 g/day over 30 min after ATO) for 5 days a week for 5 weeks (25 doses). Eleven AML patients were enrolled, including six previously untreated elderly patients aged 66-84 years in whom five had antecedent hematological disorder (ADH). Among 10 evaluable patients, one achieved a CR one a CRi and 4 patients had disappearance of blasts from peripheral blood and bone marrow. Five of the six responders were seen in previously untreated elderly patients. ATO related toxicity was mild. The combination of ATO and AA has limited clinical meaningful antileukemia activity in patients with non-APL AML.

Topics: Adult; Aged; Aged, 80 and over; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Drug Therapy, Combination; Female; Humans; Infusions, Intravenous; Leukemia, Myeloid, Acute; Male; Middle Aged; Oxides; Treatment Outcome

Topics: Adult; Aged; Angiogenesis Inhibitors; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Azacitidine; Bone Marrow; Bone Marrow Cells; Cohort Studies; Decitabine; Dose-Response Relationship, Drug; Female; Gene Expression Profiling; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; Myelodysplastic Syndromes; Neovascularization, Pathologic; Oxides; Young Adult

L-ascorbic acid (LAA) modifies the in vitro growth of leukemic cells from approximately 50% of patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). To test the hypothesis that depletion of LAA, alternating with supplementation to prevent scurvy, would provide therapeutic benefit, a single-arm pilot trial was conducted (ClinicalTrials.gov identifier: NCT00329498). Experimental results: During depletion phase, patients with refractory AML or MDS were placed on a diet deficient in LAA; during supplementation phase, patients received daily intravenous administration of LAA. An in vitro assay was performed pretherapy for LAA sensitivity of leukemic cells from individual patients.. Of 18 patients enrolled, eight of 16 evaluable patients demonstrated a clinical response. Responses were obtained during depletion (four patients) as well as during supplementation (five patients) but at a pharmacologic plasma level achievable only with intravenous administration. Of nine patients for whom the in vitro assay indicated their leukemic cells were sensitive to LAA, seven exhibited a clinical response; compared with none of six patients who were insensitive to LAA.. The clinical benefit, along with a conspicuous absence of significant adverse events, suggests that further testing of LAA depletion alternating with pharmacologic dose intravenous supplementation in patients with these and other malignancies is warranted.

Topics: Adult; Aged; Ascorbic Acid; Female; Humans; Karyotyping; Leukemia, Myeloid, Acute; Male; Middle Aged; Myelodysplastic Syndromes; Prospective Studies; Risk Assessment

Vitamin C is an essential vitamin that acts as a co-factor for many enzymes involved in epigenetic regulation in humans. Low vitamin C levels in hematopoietic stem cells (HSC) promote self-renewal and vitamin C supplementation retards leukaemogenesis in vitamin C-deficient mouse models. Studies on vitamin C levels in patients with myeloid malignancies are limited. We thus conducted a retrospective analysis on a prospective cohort of patients with myeloid malignancies on whom plasma vitamin C levels were measured serially at diagnosis and during treatment. Baseline characteristics including hematological indices, cytogenetics, and molecular mutations are described in this cohort. Among 64 patients included in our study, 11 patients (17%) had low vitamin C levels. We noted a younger age at diagnosis for patients with myeloid malignancies who had low plasma vitamin C levels. Patients with low plasma vitamin C levels were more likely to have acute myeloid leukemia compared to other myeloid malignancies. Low vitamin C levels were associated with ASXL1 mutations. Our study calls for further multi-institutional studies to understand the relevance of low plasma vitamin C level in myeloid neoplasms, the role of vitamin C deficiency in leukemogenesis, and the potential benefit of vitamin C supplementation.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Epigenesis, Genetic; Humans; Leukemia, Myeloid, Acute; Mice; Mutation; Myeloproliferative Disorders; Prospective Studies; Retrospective Studies

Vitamin C has been demonstrated to regulate hematopoietic stem cell frequencies and leukemogenesis by augmenting and restoring Ten-Eleven Translocation-2 (TET2) function, potentially acting as a promising adjunctive therapeutic agent for leukemia. However, glucose transporter 3 (GLUT3) deficiency in acute myeloid leukemia (AML) impedes vitamin C uptake and abolishes the clinical benefit of vitamin C. In this study, we aimed to investigate the therapeutic value of GLUT3 restoration in AML. In vitro GLUT3 restoration was conducted with the transduction of GLUT3-overexpressing lentivirus or the pharmacological salvage with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) treatment to OCI-AML3, a naturally GLUT3-deficient AML cell line. The effects of GLUT3 salvage were further confirmed in patient-derived primary AML cells. Upregulation of GLUT3 expression made AML cells successfully augment TET2 activity and enhanced the vitamin C-induced anti-leukemic effect. Pharmacological GLUT3 salvage has the potential to overcome GLUT3 deficiency in AML and improves the antileukemic effect of vitamin C treatments.

Topics: Ascorbic Acid; Dioxygenases; DNA-Binding Proteins; Glucose Transporter Type 3; Humans; Leukemia, Myeloid, Acute; Translocation, Genetic; Vitamin A

Recent studies have highlighted the role of vitamin C and D in acute myeloid leukemia (AML). In 2018, we changed our practices to add both vitamins to the supportive care for all consecutive patients with AML undergoing intensive chemotherapy. In this study, we compared the outcomes of patients treated before and after this change in practice. From 2015 to 2020, 431 patients were included, 262 of whom received no supplementation and 169 of whom received vitamin supplementation. Vitamin C and vitamin D was administered from day 10 of chemotherapy until hematologic recovery from induction and consolidation. Most patients presented at diagnosis with low levels of vitamin C and D. Upon recovery from induction, vitamin D levels among the vitamin C/D group significantly increased compared with those at diagnosis, and pretransplant levels were significantly higher in the vitamin C/D group compared with the control group (median of 33 vs 19 ng/mL; P < .0001). During induction, the rates of bacterial or fungal infection, hemorrhage, or macrophage activation syndrome were lower in the vitamin C/D group, whereas there was no difference in response rate, relapse incidence, and overall survival (OS). However, the multivariate analysis for OS showed a significant interaction between vitamin C/D and NPM1 mutation, meaning that vitamin C/D supplementation was significantly and independently associated with better OS in patients with NPM1 mutations (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.30-0.90; P = .019) compared with patients with wild-type NPM1 (HR, 1.01; 95% CI, 0.68-1.51; P = .95). In conclusion, vitamin C/D supplementation is safe and could influence the outcomes of patients with AML undergoing intensive chemotherapy.

Topics: Ascorbic Acid; Dietary Supplements; Humans; Leukemia, Myeloid, Acute; Mutation; Nucleophosmin; Prognosis; Vitamin D; Vitamins

Citrus fruits are a natural source of ascorbic acid, and exosome-like nanovesicles obtained from these fruits contain measurable levels of ascorbic acid. We tested the ability of grapefruit-derived extracellular vesicles (EVs) to inhibit the growth of human leukemic cells and leukemic patient-derived bone marrow blasts. Transmission electron microscopy and nanoparticle tracking analysis (NTA) showed that the obtained EVs were homogeneous exosomes, defined as exosome-like plant-derived nanovesicles (ELPDNVs). The analysis of their content has shown measurable amounts of several molecules with potent antioxidant activity. ELPDNVs showed a time-dependent antiproliferative effect in both U937 and K562 leukemic cell lines, comparable with the effect of high-dosage ascorbic acid (2 mM). This result was confirmed by a clear decrease in the number of AML blasts induced by ELPDNVs, which did not affect the number of normal cells. ELPDNVs increased the ROS levels in both AML blast cells and U937 without affecting ROS storage in normal cells, and this effect was comparable to ascorbic acid (2 mM). With our study, we propose ELPDNVs from grapefruits as a combination/supporting therapy for human leukemias with the aim to improve the effectiveness of the current therapies.

Topics: Ascorbic Acid; Citrus paradisi; Exosomes; Humans; Leukemia, Myeloid, Acute; Organic Agriculture; Reactive Oxygen Species

The epigenetic treatment by 3-Deazaneplanocin A (DZNep), a histone methyltransferase inhibitor, shows great potential against acute myeloid leukemia (AML). However, the variant sensitivity and incomplete response to DZNep are commonly observed. Here, we reveal that vitamin C (Vc) dramatically promotes DZNep response against leukemic cells in different cell lines and primary AML samples. Vc enhances apoptosis and differentiation induced by DZNep in different AML cell lines in vitro and reduces leukemia progression in vivo. At the molecular level, Vc downregulates an enzyme of serine synthesis named D-3-phosphoglycerate dehydrogenase (PHGDH), as well as BCL2, an anti-apoptotic gene. Over-expression of PHGDH reverses the Vc-enhanced anti-leukemic effect of DZNep in AML cells. Therefore, our findings provide an effective approach to reduce the resistance against epigenetic treatment by Vc, which shows a potential improvement of their combination in AML patients.

Topics: Adenosine; Ascorbic Acid; Enhancer of Zeste Homolog 2 Protein; Histone Methyltransferases; Humans; Leukemia, Myeloid, Acute

Vitamin C suppresses leukaemogenesis by modulating Tet methylcytosine dioxygenase (TET) activity. However, its beneficial effect in the treatment of patients with acute myeloid leukaemia (AML) remains controversial. In this study, we aimed to identify a potential predictive biomarker for vitamin C treatment in AML.. Gene expression patterns and their relevance to the survival of AML patients were analysed with The Cancer Genome Atlas (TCGA) and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database cases. In vitro experiments were performed on AML cell lines, a SLC2A3-knockdown cell line and patient-derived primary AML cells.. SLC2A3 expression was significantly decreased in leukaemic blast cells. Below-median SLC2A3 expression was associated with poor overall survival. Low SLC2A3 expression was associated with less effective demethylation, and a diminished vitamin C effect in the AML and lymphoma cell lines. SLC2A3 knockdown in the KG-1 cell line decreased the response of vitamin C. In patient-derived primary AML cells, vitamin C only restored TET2 activity when SLC2A3 was expressed.. SLC2A3 could be used as a potential biomarker to predict the effect of vitamin C treatment in AML.

Topics: Ascorbic Acid; Biomarkers, Tumor; Dioxygenases; Disease Progression; DNA-Binding Proteins; Female; Gene Expression Regulation, Neoplastic; Glucose Transporter Type 3; Humans; Leukemia, Myeloid, Acute; Male; Microarray Analysis; Progression-Free Survival; Proto-Oncogene Proteins

To investigate the effects of high dose vitamin C on proliferation and apoptosis of acute myeloid leukemia (AML) cell lines including HL-60, U937 and primary CD34. The proliferation of HL-60 and U937 cells could be inhibited by high dose vitamin C, which showed a concentration-dependent manner (r=-0.9664; r=-0.9796). HL-60 and U937 cells were treated with different concentrations of vitamin C (8 and 20 mmol/L) for 24 hours, respectively, it was found that with the increasing of vitamin C concentration, cell apoptosis rate was significantly increased (r=0.9905; r=0.9971), and the expression of apoptosis related proteins including cleaved caspase 3, cleaved caspase-9 and cleaved PARP was aslo significantly increased with the increasing of concentration. In addition, it was found that with or without the mutation of TET2, high dose vitamin C could inhibit the proliferation (r=-0.9719; r=-0.9699) and promote the apoptosis (r=0.9998; r=0.9901) of primary CD34. High dose vitamin C can inhibit the proliferation and promote the apoptosis of acute myeloid leukemia cells, and selectively kill primary CD34. 大剂量维生素C对急性髓系白血病细胞增殖、凋亡的影响.. 探讨大剂量维生素C对急性髓系白血病细胞株HL-60、U937及原代急性髓系白血病细胞增殖及凋亡的影响.. 大剂量维生素C能够抑制急性髓系白血病细胞的增殖、促进其凋亡，并且具有选择性杀伤原代CD34

Topics: Apoptosis; Ascorbic Acid; Cell Proliferation; HL-60 Cells; Humans; Leukemia, Myeloid, Acute; U937 Cells

Topics: Antioxidants; Ascorbic Acid; Dioxygenases; DNA-Binding Proteins; Humans; Leukemia, Myeloid, Acute; Proto-Oncogene Proteins; Remission Induction; Treatment Outcome; WT1 Proteins

The genomes of myeloid malignancies are characterized by epigenomic abnormalities. Heterozygous, inactivating ten-eleven translocation 2 (TET2) mutations and neomorphic isocitrate dehydrogenase (IDH) mutations are recurrent and mutually exclusive in acute myeloid leukaemia genomes. Ascorbic acid (vitamin C) has been shown to stimulate the catalytic activity of TET2 in vitro and thus we sought to explore its effect in a leukaemic model expressing IDH1

Topics: Animals; Ascorbic Acid; Cell Differentiation; Cell Proliferation; DNA-Binding Proteins; Epigenesis, Genetic; Epigenomics; Isocitrate Dehydrogenase; Leukemia, Myeloid, Acute; Mice; Mice, Inbred C57BL; Mutation; Transcription Factors

Decitabine is widely used in the treatment of acute myeloid leukemia (AML) in elderly patients. Low-dose Vitamin C has also been indicated to induce DNA demethylation at the cellular level. However, little is known whether low-dose Vitamin C has a synergistic effect with decitabine in clinic.. The effect of combined low-dose Vitamin C and decitabine on cell proliferation, the cell cycle, apoptosis and the expression level and activity of TET2 was investigated in HL60 and NB4 human leukemic cells. Additionally, we analyzed the clinical outcomes of 73 elderly AML patients who received A-DCAG (intravenous Vitamin C [IVC] plus DCAG [n = 39]) or DCAG (n = 34) treatment.. We found that low-dose Vitamin C and decitabine has a synergistic efficacy on proliferation, apoptosis, TET2 expression and activity, compared to drug-alone treatment in HL60 and NB4 cell lines in vitro. In clinic, feasibility and safety evaluations revealed that patients who received A-DCAG regimen have a higher complete remission (CR) rate than those who received the DCAG regimen (79.92% vs. 44.11%; P = 0.004) after one cycle of chemotherapy. The median overall survival (OS) was better in the A-DCAG group compared with the DCAG group (15.3 months vs. 9.3 months, P = 0.039). Patients with adverse cytogenetics did benefit from CR. There was no clinically significant additional toxicity observed with the addition of IVC.. On the basis of these results, the addition of IVC at low doses to DCAG appeared to improve CR and prolong OS, compared with DCAG, in elderly patients with AML.

Topics: Aged; Aged, 80 and over; Ascorbic Acid; Decitabine; Dioxygenases; Disease-Free Survival; DNA-Binding Proteins; Female; HL-60 Cells; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; Proto-Oncogene Proteins; Survival Rate

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

Loss-of-function mutations in TET2 occur frequently in patients with clonal hematopoiesis, myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML) and are associated with a DNA hypermethylation phenotype. To determine the role of TET2 deficiency in leukemia stem cell maintenance, we generated a reversible transgenic RNAi mouse to model restoration of endogenous Tet2 expression. Tet2 restoration reverses aberrant hematopoietic stem and progenitor cell (HSPC) self-renewal in vitro and in vivo. Treatment with vitamin C, a co-factor of Fe2

Topics: Animals; Ascorbic Acid; Cell Death; Cell Line, Tumor; Dioxygenases; DNA Methylation; DNA-Binding Proteins; Gene Knockdown Techniques; Humans; Leukemia, Myeloid, Acute; Mice; Myelodysplastic Syndromes; Neoplasm Transplantation; Poly (ADP-Ribose) Polymerase-1; Proto-Oncogene Proteins; Transcription, Genetic; Transplantation, Heterologous; Vitamins

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy whose incidence is growing in developed countries. In the relapse setting, very limited therapeutic options are available and in most cases only palliative care can be offered to patients. The effect of a composite formulation that contains several antioxidants, Ocoxin Oral solution (OOS), was tested in this condition. When analyzed in vitro, OOS exhibited anti-AML action that was both time and dose dependent. In vivo OOS induced a ralentization of tumor growth that was due to a decrease in cell proliferation. Such effect could, at least partially, be due to an increase in the cell cycle inhibitor p27, although other cell cycle proteins seemed to be altered. Besides, OOS induced an immunomodulatory effect through the induction of IL6. When tested in combination with other therapeutic agents normally used in the treatment of AML patients, OOS demonstrated a higher antiproliferative action, suggesting that it may be used in combination with those standard of care treatments to potentiate their antiproliferative action in the AML clinic.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Female; Folic Acid; Humans; Leukemia, Myeloid, Acute; Mice; Mice, Nude; Pantothenic Acid; Plant Extracts; Random Allocation; Vitamin B 12; Vitamin B 6; Xenograft Model Antitumor Assays; Zinc Sulfate

Vitamin C deficiency in developed countries is typically observed in patients with unique clinical conditions such as cystic fibrosis or anorexia nervosa, or in patients on long-term tube feeds. We report here a clinical observation in six pediatric and adolescent patients (median age 17.5 yr, range 9.8-23.5 yr) with chronic GVHD with mucous membrane involvement found to be vitamin C deficient. These patients' baseline serum vitamin C levels ranged from <0.12 to 0.94 mg/dL (normal value 0.20-1.90 mg/dL), with a mean level 0.56 ± 0.36 mg/dL and a median level 0.6 mg/dL. Among these patients, signs and symptoms of mucositis failed to respond to standard chronic GVHD therapy. After receiving treatment with 2000 mg of ascorbic acid by mouth, daily patients displayed increased serum vitamin C levels. Clinically, this correlated with a remarkable improvement in patients' mucositis and ability to eat.

Topics: Administration, Oral; Adolescent; Adult; Ascorbic Acid; Ascorbic Acid Deficiency; Child; Chronic Disease; Graft vs Host Disease; Humans; Leukemia, Myeloid, Acute; Mucositis; Mucous Membrane; Myelodysplastic Syndromes; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Prednisone; Scurvy; Stem Cell Transplantation; Young Adult

Tigecycline is a broad-spectrum, first-in-class glycylcycline antibiotic currently used to treat complicated skin and intra-abdominal infections, as well as community-acquired pneumonia. In addition, we have demonstrated that tigecycline also has in vitro and in vivo activity against acute myeloid leukemia (AML) due to its ability to inhibit mitochondrial translation. Tigecycline is relatively unstable after reconstitution, and this instability may limit the use of the drug in ambulatory infusions for the treatment of infection and may prevent the development of optimal dosing schedules for the treatment of AML. This study sought to identify a formulation that improved the stability of the drug after reconstitution and maintained its antimicrobial and antileukemic activity. A panel of chemical additives was tested to identify excipients that enhanced the stability of tigecycline in solution at room temperature for up to one week. We identified a novel formulation containing the oxygen-reducing agents ascorbic acid (3 mg/mL) and pyruvate (60 mg/mL), in saline solution, pH 7.0, in which tigecycline (1 mg/mL) remained intact when protected from light for at least 7 days. This formulation also preserved the drug's antibacterial and antileukemic activity in vitro. Moreover, the novel formulation retained tigecycline's antileukemic activity in vivo. Thus, we identified and characterized a novel formulation for tigecycline that preserves its stability and efficacy after reconstitution.

Topics: Animals; Anti-Bacterial Agents; Ascorbic Acid; Cell Line, Tumor; Cell Survival; Chromatography, High Pressure Liquid; Drug Stability; Humans; Immunoblotting; Leukemia, Myeloid, Acute; Mice; Mice, SCID; Minocycline; Pyruvic Acid; Tigecycline

L-ascorbic acid (LAA) shows cytotoxicity and induces apoptosis of malignant cells in vitro, but the mechanisms by which such effects occur have not been elucidated. In the present study, we provide evidence that the ERK MAP kinase pathway is activated in response to LAA (< 1 mM) in acute myeloid leukemia cell lines. LAA treatment of cells induces a dose-dependent phosphorylation of extracellular signal-regulated kinases (ERK) and results in activation of its catalytic domain. Our data also demonstrate that the small G protein Raf1 and MAPK-activated protein kinase 2 are activated by LAA as an upstream and a downstream regulator of ERK, respectively. Although the ERK pathway has been known to activate cell proliferation, pharmacologic inhibition of ERK reduces LAA-dependent apoptosis and growth inhibitory response of acute myeloid leukemia cell lines, suggesting that this signaling cascade positively regulates induction of apoptotic response by LAA.

Topics: Apoptosis; Ascorbic Acid; Cell Line, Tumor; Cell Survival; HL-60 Cells; Humans; Leukemia, Myeloid, Acute; MAP Kinase Signaling System; Phosphorylation; Proto-Oncogene Proteins c-raf; Signal Transduction

L-Ascorbic acid (LAA) is being investigated clinically for the treatment of patients with acute myeloid leukemia (AML) based on the observed effects of LAA on AML progenitor cells in vitro. However, the mechanism for LAA-induced cytoreduction remains to be elucidated. LAA at concentrations of 0.25-1.0 mM induced a dose- and time-dependent inhibition of proliferation in three AML cell lines and also in leukemic cells from peripheral blood specimens obtained from three patients with AML. In contrast, ovarian cancer cell lines were only minimally affected. Flow cytometric analysis showed that LAA at concentrations of 0.25-1.0 mM could significantly induce apoptosis in the AML cell lines. LAA induced oxidation of glutathione to oxidized form (GSSG) and subsequent H(2)O(2) accumulation in a concentration-dependent manner, in parallel to induction of apoptosis. The direct role of H(2)O(2) in the induction of apoptosis in AML cells was clearly demonstrated by the finding that catalase could completely abrogate LAA-induced apoptosis. Induction of apoptosis in LAA-treated AML cells involved a dose-dependent increase of Bax protein, release of cytochrome C from mitochondria to cytosol, activation of caspase 9 and caspase 3, and cleavage of poly[ADP-ribose]polymerase. In conclusion, LAA can induce apoptosis in AML cells, and this is clearly due to H(2)O(2) which accumulates intracellularly as a result of oxidation of reduced glutathione by LAA.

Topics: Apoptosis; Ascorbic Acid; Caspase 3; Caspase 9; Caspases; Cell Proliferation; Cytochromes c; Enzyme Activation; Glutathione; HL-60 Cells; Humans; Hydrogen Peroxide; Leukemia, Myeloid, Acute; Mitochondria; Oxidation-Reduction; Tumor Cells, Cultured

There is increasing evidence that L-ascorbic acid (LAA) is selectively toxic to some types of cancer cells at pharmacological concentrations, functioning as a pro-oxidant rather than as an anti-oxidant. However, the molecular mechanisms by which LAA initiates cellular signaling leading to cell death are still unclear. In an effort to gain insight into these mechanisms, the effects of LAA on eukaryotic transcription nuclear factor NF-kappaB and cyclooxygenase-2 (COX-2) expression were investigated. In the present study, LAA suppressed DNA binding activity of NF-kappaB, composed of a p65/p50 heterodimer, through inhibition of degradation of inhibitory kappaB-alpha (IkappaB-alpha) and prevention of nuclear translocation of p65. The inhibitory effect of LAA on NF-kappaB activity was dependent upon glutathione levels in HL-60 cells, as well as generation of H2O2 but not superoxide anion. LAA also downregulated the expression of COX-2, which has a NF-kappaB binding site on its promoter, through repressing NF-kappaB DNA binding activity. Moreover, cotreatment of 1 microM arsenic trioxide (As2O3) with various concentrations of LAA enhanced an LAA-induced repression of NF-kappaB activity and COX-2 expression. In conclusion, our data suggest that LAA exerts its anti-tumor activity through downregulation of NF-kappaB activity and COX-2 expression, and these inhibitory effects can be enhanced by co-treatment with As2O3.

Topics: Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Cyclooxygenase 2; DNA; Down-Regulation; Electrophoretic Mobility Shift Assay; Glutathione; HL-60 Cells; Humans; Hydrogen Peroxide; Isoenzymes; Leukemia, Myeloid, Acute; Membrane Proteins; NF-kappa B; Oxides; Prostaglandin-Endoperoxide Synthases; Protein Subunits; Superoxides; Tosylphenylalanyl Chloromethyl Ketone; Transcription Factor RelA

To examine the prevalence of supplement use in persons before receiving hematopoietic stem cell transplant (HSCT) and the association of select supplements with outcomes.. This observational cohort study included a questionnaire on supplement use before HSCT. Nonrelapse mortality, recurrence/relapse, and mortality or relapse (the inverse of disease-free survival) were followed to two years. Subjects/Setting Persons receiving HSCT at the Fred Hutchinson Cancer Research Center between September 1994 and December 1997 were eligible (N=1,182). Statistical Analyses Performed Descriptive statistics and univariate and Cox regression analyses were conducted.. Sixty-six percent of patients used supplements (31% vitamin C, 19% vitamin E, and 20% herbs or others preparations). Vitamin C at > or =500 mg/day was inversely associated with recurrence among persons with breast cancer (RR=0.11; 95% CI, 0.02-0.89; P=.03). However, among persons with acute leukemia, vitamin C at > or =500 mg/day was positively associated with nonrelapse mortality (RR=2.25; 95% CI, 1.33-3.83; P=.01) and mortality or relapse (RR=1.63; 95% CI, 1.09-2.44; P=.01), respectively. Vitamin E at > or =400 IU/day was positively associated with mortality or relapse (RR=1.77; 95% CI, 1.06 -2.96; P=.02). Applications/Conclusions Though this work was observational, the results suggest supplemental vitamin C before therapy may be beneficial in persons with breast cancer but both vitamin C and vitamin E may increase risk in persons with acute leukemia receiving HSCT. Practitioners should document supplement use in subjects receiving therapy for cancer.

Topics: Adolescent; Adult; Antioxidants; Ascorbic Acid; Breast Neoplasms; Cohort Studies; Dietary Supplements; Disease-Free Survival; Female; Hematopoietic Stem Cell Transplantation; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Acute; Male; Middle Aged; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proportional Hazards Models; Vitamin E

The human myeloid leukemia cell line HL-60 transports the oxidized form of ascorbic acid, dehydroascorbic acid (DHA), and accumulates reduced ascorbic acid. We studied the effect of ascorbic acid loading on apoptosis induced by serum- and glucose-free culture and by oxidative stress induced by H2O2. Uptake accumulation studies indicated that incubation of HL-60 cells with DHA resulted in the accumulation of intracellular ascorbic acid which decreased with time when cells were incubated in DHA-free medium. Exposure of HL-60 cells to increasing concentrations of H2O2 resulted in dose-dependent intracellular accumulation of peroxides, as determined by the use of the oxidation-sensitive fluorescent probe 2',7'-dichlorofluorescin-diacetate (DCFH-DA), which was accompanied by a decrease in intracellular ascorbic acid and an increase in apoptosis. A dramatic decrease in intracellular ascorbic acid was noted when preloaded HL-60 cells were exposed to 150 microM H2O2 (the concentration dropped from 5.2 +/- 0.6 mM to 3.6 +/- 0.1 mM in cells preincubated with 150 microM DHA). A dose-dependent protective effect of DHA was observed. Ascorbic acid loading also provided strong protection from apoptosis associated with serum- and glucose-free culture. Flow cytometry studies showed that exposure of HL-60 cells to 150 microM H2O2 resulted in decreased Bcl-2 expression that was associated with enhanced apoptosis (up to 33.6 +/- 2.6%). No significant variation of Bcl-2 expression was measured following exposure of HL-60 cells, loaded with ascorbic acid, to 150 microM H2O2 and only a slight increase (up to 10.1 +/- 3.1%) in apoptosis. These findings indicate that ascorbic acid can inhibit apoptosis induced by oxidative stress in HL-60 cells.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Dehydroascorbic Acid; Fluoresceins; Fluorescent Dyes; Gene Expression; Genes, bcl-2; HL-60 Cells; Humans; Hydrogen Peroxide; Leukemia, Myeloid, Acute; Oxidative Stress; Peroxides

Total body irradiation (TBI) is a routine preconditioning procedure for the treatment of leukemia and aplastic anemia, prior to bone marrow transplantation (BMT). Ionizing radiation generates reactive oxygen derived species (ROS) that can be removed by antioxidants. Our purpose is to determine the antioxidant status of patients undergoing TBI by evaluating the oxidant stress and their antioxidant capacity.. We evaluated by cyclic voltammetry (CV) the total antioxidant capacity (TAC) in plasma of 14 patients undergoing TBI prior to BMT. The levels of the antioxidants, ascorbic acid (AA) and uric acid (UA) were determined by HPLC-ECD. The oxidant stress level was calculated by the ratio [dehydro ascorbic acid]/total ascorbic acid].. TAC was reduced by 36% (p < 0.02) but after 4 months recovered to a level 22% higher than before the treatment (p < 0.05). Both, AA and UA, decreased following irradiation by 84% (p < 0.02) and 24% (p < 0.05) respectively, but returned to a level of 21% and 320% after 4 months compared to baseline values. The changes in [UA] were affected by Allopurinol (xanthine oxidase inhibitor), given as a routine pretransplant therapy until day -1. The [dehydroascorcbic acid]/[total ascorbic acid] (%) was 45% (range of normal controls = 13.2 +/- 1.5%) and increased by 69% following TBI. In order to obtain a decrease in the TAC of plasma in vitro, comparable to that in vivo, a 1000 fold higher dose of irradiation was required.. TBI caused a pronounced decrease in antioxidant capacity and an excessive increase in oxidant stress. We assume that TBI alters antioxidant homeostasis greatly enhancing the stress damage. CV measurements may lead to a better understanding of the balance between oxidant stress and antioxidant utilization, and to a reconsideration of the routine use of Allopurinol as pretreatment for TBI, and antioxidant support before and/or after TBI.

Topics: Adolescent; Adult; Anemia, Aplastic; Antioxidants; Ascorbic Acid; Bone Marrow Transplantation; Child; Chromatography, High Pressure Liquid; Dehydroascorbic Acid; Female; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; Oxidative Stress; Uric Acid; Whole-Body Irradiation

Pharmacologically attainable concentrations of ascorbic acid are highly toxic for U937 cells (a human promyelocytic cell line), and this response appears to be mediated by H2O2. This inference finds experimental support in the following observations: 1) toxic levels of H2O2 are readily generated upon dissolution of survival-range concentrations of ascorbic acid in the culture medium; 2) the lethal effects elicited by ascorbic acid or reagent H2O2 are prevented by the addition of either catalase or the intracellular iron chelator o-phenanthroline and are characterized by similar temporal dependence; 3) U937 cells resistant to hydrogen peroxide are cross-resistant to ascorbic acid; 4) under the conditions utilized in this study, H2O2 and ascorbate promote similar modes of cell death (i.e., necrosis); and 5) cell killing provoked by H2O2 or ascorbate is an inverse function of cell density and is suppressed by coculturing U937 target cells with human erythrocytes (at a density far below that present in the blood) and human fibroblasts. Cytoprotection was not observed using catalase-depleted erythrocytes. Taken together, these results strongly suggest that H2O2 is entirely responsible for the ascorbate-induced U937 cell killing. We therefore propose that it is unlikely that the vitamin damages or kills tumor cells of normal tissues in vivo via the H2O2 based mechanism, because the oxidant would be removed promptly by the neighboring cells.

Topics: Ascorbic Acid; Catalase; Cell Death; Dose-Response Relationship, Drug; Erythrocytes; Fibroblasts; Humans; Hydrogen Peroxide; Leukemia, Myeloid, Acute; Tumor Cells, Cultured

Electron spin resonance (ESR) spectra of lyophilized erythrocytes obtained from patients with acute myeloid leukemia (AML) show, in comparison to controls, a characteristic change especially in the low-field region of the spectrum concomitant with a reduction of the spin concentration. This effect can be simulated by addition of SH-containing substances (e.g. reduced glutathione or cysteine) to healthy erythrocytes. S-S containing compounds exhibit no effect. Since SH-containing substances can hardly permeate plasma membranes, the membrane surface seems to be defective in the case of "AML" erythrocytes. Furthermore, it can be concluded that the concentration of SH-containing substances, such as cysteine, is increased in the plasma of AML-patients, which could be confirmed by HPLC-measurements. In the case of a successful treatment of the patients with alexan, daunoblastin, and thioguanine the spin concentration increased again and the resulting ESR spectrum is very similar to the control spectrum. It should be pointed out, that the ascorbic acid concentration is very low in both plasma and erythrocytes of AML patients.

Topics: Ascorbic Acid; Electron Spin Resonance Spectroscopy; Erythrocytes; Glutathione; Glycoproteins; Humans; Leukemia, Lymphoid; Leukemia, Myeloid, Acute; Sulfhydryl Compounds

We tested the hypothesis that the rate of cellular uptake of dehydroascorbate in cultures of developing granulocyte-macrophage progenitors in vitro would serve as a biochemical marker of neutrophil maturation. Suspension cultures of low-density, nonadherent, T-lymphocyte-depleted bone marrow cells from eight normal volunteers were cultured in medium containing 10% human placental conditioned medium and were harvested at intervals over 14 days. The harvested cells were tested for their ability to take up dehydroascorbate. Mean cellular uptake rate increased 12-fold by Day 10, at which time the cells had differentiated to neutrophils. Uptake increased by less than 2-fold in cells which had been induced to differentiate to mature mononuclear phagocytes with 12-O-tetradecanoylphorbol-13-acetate. Additional studies using HL-60 cells induced to differentiate with dimethyl sulfoxide or 12-O-tetradecanoylphorbol-13-acetate support the view that a major increase in dehydroascorbate uptake in cultured granulopoietic progenitors is a manifestation of a neutrophil differentiation.

Topics: Ascorbic Acid; Cell Differentiation; Dehydroascorbic Acid; Granulocytes; Humans; In Vitro Techniques; Leukemia, Myeloid, Acute; Time Factors

The suppressive effect of L-ascorbic acid on the growth of bone marrow cells from patients with acute nonlymphocytic leukemia was studied using a modified agar culture method featuring daily feeding to allow the growth of leukemic cell colonies. In seven of 28 patients (25%), the numbers of leukemic cell colonies grown in culture were reduced to 21% of control by the addition of L-ascorbic acid (0.3 mM) to the culture medium. Glutathione did not suppress leukemic cell colonies although it has a similar oxidation-reduction potential to that of L-ascorbic acid. The addition of L-ascorbic acid reduced the pH of the medium. However, a comparable reduction of pH by the addition of HCl did not suppress leukemic cell colonies. In simultaneous cultures for leukemic and normal marrow cells, the suppression of leukemic cell colony was noted with a concentration of L-ascorbic acid as low as 0.1 mM (a concentration achievable in vivo), but normal myeloid colonies were not suppressed until the concentration of L-ascorbic acid reached an extremely high level (1 mM). In conclusion, growth of leukemic cells in culture was suppressed by L-ascorbic acid in a substantial proportion of patients with acute nonlymphocytic leukemia. This suppression was a specific effect of L-ascorbic acid and was not due to its oxidation-reduction potential or pH change. Leukemic cells were selectively affected at an L-ascorbic acid concentration attainable in vivo while normal hemopoietic cells were not suppressed.

Topics: Adult; Aged; Ascorbic Acid; Bone Marrow; Cell Division; Colony-Forming Units Assay; Female; Hematopoietic Stem Cells; Humans; In Vitro Techniques; Leukemia; Leukemia, Erythroblastic, Acute; Leukemia, Myeloid, Acute; Male; Middle Aged

Topics: Agglutination Tests; Ascorbic Acid; Candida; Candidiasis; Humans; Immunodiffusion; In Vitro Techniques; Iron; Leukemia, Lymphoid; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Lymphoma; Multiple Myeloma; Polycythemia Vera; Precipitin Tests; Transferrin