ascorbic-acid and Leukemia--Myelogenous--Chronic--BCR-ABL-Positive

Topics: 2-Methoxyestradiol; Animals; Ascorbic Acid; fms-Like Tyrosine Kinase 3; Humans; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mice; MicroRNAs; Proto-Oncogene Proteins c-akt; RNA, Neoplasm; Signal Transduction; Xenograft Model Antitumor Assays

This work aimed to evaluate oxidative stress in chronic myeloid leukemia (CML) patients treated with tunisian (IM) vs controls and in CML patients with resistance to IM vs patients without resistance to IM.. The study included 40 CML patients and 34 controls. Of 40 patients with CML, 26 patients were developed in resistance to IM. The oxidant/antioxidant markers were evaluated by spectrophotometric methods for all used samples.. For CML patients, increased malondialdehyde (MDA) and advanced oxidation protein products (AOPP) levels were found compared to controls (P < .001; P = .01). Higher catalase (CAT) activity (P = .048) and lower superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, reduced Glutathione (GSH) and vitamin C levels were found in CML patients (P < .001). The comparison between the resistant vs no-resistant CML patients revealed higher MDA level (P = .02) and CAT and SOD activities in IM-resistant patients (P = .04, P = .03). GPx activity was reduced (P = .04). Furthermore, increased mean ratio of MDA/GSH, MDA/GPx, and SOD/(GPx + CAT) was found in IM-resistant patients as compared with no-resistant (P = .01, P = .01, P = .035). The mean ratio of GPx/GSH in the IM-resistant CML patients was lower than in IM no-resistant one (P = .039). For IM-resistant patients, we found negative correlation between MDA level and the ratio SOD/(CAT + GPx) (r = -0.46, P = .002); and positive correlation between SOD and (CAT + GPx) activities (r = 0.38, P = .06) and between GSH level and GPx activity (r = 0.53, P = .01).. Our results have shown a highly disturbed oxidative profile in IM-resistant CML patients as compared to no-resistant. The H

Topics: Adult; Advanced Oxidation Protein Products; Antineoplastic Agents; Antioxidants; Ascorbic Acid; Case-Control Studies; Drug Resistance, Neoplasm; Enzymes; Female; Glutathione; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Male; Malondialdehyde; Middle Aged; Oxidative Stress; Treatment Outcome; Tunisia

Among different features of cancer cells, two of them have retained our interest: their nearly universal glycolytic phenotype and their sensitivity towards an oxidative stress. Therefore, we took advantage of these features to develop an experimental approach by selectively exposing cancer cells to an oxidant insult induced by the combination of menadione (vitamin K(3)) and ascorbate (vitamin C). Ascorbate enhances the menadione redox cycling, increases the formation of reactive oxygen species and kills K562 cells as shown by more than 65% of LDH leakage after 24 hr of incubation. Since both lactate formation and ATP content are depressed by about 80% following ascorbate/menadione exposure, we suggest that the major intracellular event involved in such a cytotoxicity is related to the impairment of glycolysis. Indeed, NAD(+) is rapidly and severely depleted, a fact most probably related to a strong Poly(ADP-ribose) polymerase (PARP) activation, as shown by the high amount of poly-ADP-ribosylated proteins. The addition of N-acetylcysteine (NAC) restores most of the ATP content and the production of lactate as well. The PARP inhibitor dihydroxyisoquinoline (DiQ) was able to partially restore both parameters as well as cell death induced by ascorbate/menadione. These results suggest that the PARP activation induced by the oxidative stress is a major but not the only intracellular event involved in cell death by ascorbate/menadione. Due to the high energetic dependence of cancer cells on glycolysis, the impairment of such an essential pathway may explain the effectiveness of this combination to kill cancer cells.

Topics: Antioxidants; Apoptosis; Ascorbic Acid; Enzyme Activation; Glycolysis; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; NAD; Necrosis; Oxidative Stress; Poly(ADP-ribose) Polymerases; Tumor Cells, Cultured; Vitamin K 3

The effect of oxidative stress induced by the ascorbate/menadione-redox association was examined in K562 cells, a human erythromyeloid leukaemia cell line. Our results show that ascorbate enhances menadione redox cycling, leading to the formation of intracellular reactive oxygen species (as shown by dihydrorhodamine 123 oxidation). The incubation of cells in the presence of both ascorbate/menadione and aminotriazole, a catalase inhibitor, resulted in a strong decrease of cell survival, reinforcing the role of H(2)O(2) as the main oxidizing agent killing K562 cells. This cell death was not caspase-3-dependent. Indeed, neither procaspase-3 and PARP were processed and only a weak cytochrome c release was observed. Moreover, we observed only 23% of cells with depolarized mitochondria. In ascorbate/menadione-treated cells, DNA fragmentation was observed without any sign of chromatin condensation (DAPI and TUNEL tests). The cell demise by ascorbate/menadione is consistent with a necrosis-like cell death confirmed by both cytometric profile of annexin-V/propidium iodide labeled cells and by light microscopy examination. Finally, we showed that a single i.p. administration of the association of ascorbate and menadione is able to inhibit the growth of K562 cells by about 60% (in both tumour size and volume) in an immune-deficient mice model. Taken together, these results reinforced our previous claims about a potential application of the ascorbate/menadione association in cancer therapy.

Topics: Animals; Ascorbic Acid; Cell Death; Cell Line, Tumor; Disease Models, Animal; Humans; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mice; Mice, Nude; Neoplasm Transplantation; Oxidative Stress; Vitamin K 3; Xenograft Model Antitumor Assays

Imatinib (STI571) is a 2-phenylaminopyrimidine derivative used mostly in the treatment of chronic myeloid leukaemia. It targets the BCR/ABL oncogenic tyrosine kinase, inhibiting its activity. Using the alkaline comet assay we showed that STI571 at concentrations ranging from 0.2 to 2 microM induced DNA damage in human leukemic K562 and BV173 cells expressing the BCR/ABL oncogene, whereas it had no effect in normal human lymphocytes and leukemic CCRF-CEM cells without the expression of BCR/ABL. Imatinib did not induce DNA strand breaks in the direct interaction with DNA as examined by the circular plasmid relaxation assay. Because the extent of DNA damage observed in the neutral and pH 12.1 versions of the comet assay was much lesser than in the alkaline version, we concluded that the drug induced DNA alkali-labile sites rather than strand breaks. K562 cells were unable to repair H(2)O(2)-induced DNA damage during a 120-min incubation, if they had been preincubated with STI571, whereas normal lymphocytes did so within 60 min. Pre-treatment of K562 cells with Vitamins A, C and E reduced the extent of DNA damage evoked by STI571. Similar results brought experiments with the nitrone spin traps POBN and PBN, suggesting that free radicals may be involved in the formation of DNA lesions induced by STI571 in K562 cells. These cells exposed to imatinib and treated with endonuclease III, formamidopyrimidine-DNA glycosylase and 3-methyladenine-DNA glycosylase II, the enzymes recognizing oxidized and alkylated bases, displayed greater extent of DNA damage than those not treated with these enzymes. Therefore, the mechanism of the anti-leukemic action of STI571 may involve not only the inhibition of BCR/ABL, but also DNA damage in the cells expressing this fusion protein. DNA damage induced by STI571 may follow from oxidative and alkylative base modifications.

Topics: Adult; Antineoplastic Agents; Apoptosis; Ascorbic Acid; Benzamides; Comet Assay; DNA Damage; DNA Repair; Fusion Proteins, bcr-abl; Humans; Imatinib Mesylate; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Lymphocytes; Male; Piperazines; Plasmids; Protein-Tyrosine Kinases; Pyrimidines; Statistics, Nonparametric; Vitamin A; Vitamin E

Imatinib, a BCR/ABL tyrosine kinase inhibitor, has shown remarkable clinical effects in chronic myelogenous leukemia. However, the leukemia cells become resistant to this drug in most blast crisis cases. The transcription factor Nrf2 regulates the gene expression of a number of detoxifying enzymes such as gamma-glutamylcysteine synthetase (gamma-GCS), the rate-limiting enzyme in glutathione (GSH) synthesis, via the antioxidant response element (ARE). In this study, we examined the involvement of Nrf2 in the acquisition of resistance to imatinib. Since oxidative stress promotes the translocation of Nrf2 from the cytoplasm to the nucleus, we also examined whether ascorbic acid, a reducing reagent, can overcome the resistance to imatinib by inhibiting Nrf2 activity.. Binding of Nrf2 to the ARE of the gamma-GCS light subunit (gamma-GCSl) gene promoter was much stronger in the imatinib-resistant cell line KCL22/SR than in the parental imatinib-sensitive cell line KCL22. The levels of gamma-GCSl mRNA and GSH were higher in KCL22/SR cells, a finding consistent with the observation of an increase in Nrf2-DNA binding. Addition of a GSH monoester to KCL22 cells resulted in an increase in the IC(50) value of imatinib. In contrast, addition of ascorbic acid to KCL22/SR cells resulted in a decrease in Nrf2-DNA binding and decreases in levels of gamma-GCSl mRNA and GSH. Consistent with these findings, ascorbic acid partly restored imatinib sensitivity to KCL22/SR.. Changes in the redox state caused by antioxidants such as ascorbic acid can overcome resistance to imatinib via inhibition of Nrf2-mediated gene expression.

Topics: Antineoplastic Agents; Ascorbic Acid; Benzamides; Blast Crisis; DNA-Binding Proteins; DNA, Neoplasm; Drug Resistance, Neoplasm; Enzyme Inhibitors; Gene Expression Regulation, Leukemic; Glutamate-Cysteine Ligase; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; NF-E2-Related Factor 2; Oxidative Stress; Piperazines; Protein Transport; Pyrimidines; Regulatory Sequences, Nucleic Acid; RNA, Neoplasm; Trans-Activators

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