8-hydroxy-2--deoxyguanosine and Leukemia

Oxidative stress combined with nullity of xenobiotic metabolizing GSTT1/GSTM1/CYP2E1 genes may increase the susceptibility of agricultural workers to adverse health effects including cancer. The present study was conducted to determine; the prevalence of polymorphisms in GSTM1, GSTT1 and CYP2E1 genes, serum 8-hydroxy-2'-deoxygunosine levels, and the role of these markers in risk of cancer among agricultural workers occupationally exposed to pesticides.. A total of 360 participants, of which 180 belonging to farming group diagnosed with leukemia (n=60), lymphoma (n=60) and breast cancers (n=60), 90 in non-farming group diagnosed with similar cancers and the other 90 as healthy controls with neither history of occupational exposure nor diagnosed with any type of cancers were recruited. Following the questionnaire survey, serum 8-OHdG and genetic polymorphisms in the three genes were determined using ELISA and PCR methods respectively.. The results of the study revealed that farm workers carrying GSTT1 null genotype had increased risk for lymphoma (OR = 5.34; 95% CI = 1.80-15.82) and breast cancer (OR=4.04; 95% CI = 1.24-13.07). For farm workers carrying GSTM1 null genotype, the risk was six-fold for breast cancer (OR = 6.88; 95% CI =1.88-25.99). Further, there found a significant difference between 8-OHdG and nullity of CYP2E1 among the farm workers diagnosed with leukemia.. The findings of the present study suggest that the polymorphisms in detoxifying genes among farm workers occupationally exposed to pesticides and the oxidative stress may likely be responsible for triggering the mechanism of malignancy.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Breast Neoplasms; Cytochrome P-450 CYP2E1; Drug-Related Side Effects and Adverse Reactions; Farmers; Female; Humans; Leukemia; Lymphoma; Pesticides; Polymorphism, Genetic; Xenobiotics

8-Hydroxy-2'-deoxyguanosine (8-OHdG), a product of oxidative DNA damage, which has been used as a sensitive and reliable marker of oxidative stress and carcinogenesis, is found in high levels in biological fluids of leukemia patients. A reliable screening method based on pattern recognition of 8-OHdG using stochastic sensors designed with graphene materials decorated with nanoparticles of TiO

Topics: 8-Hydroxy-2'-Deoxyguanosine; Biosensing Techniques; Deoxyguanosine; Electrochemical Techniques; Equipment Design; Gold; Graphite; Humans; Leukemia; Limit of Detection; Nanoparticles; Pyridines; Silver; Titanium

Benzene is an environmental pollutant known to cause leukemia in adults, and may be associated with childhood leukemia. While the mechanisms of benzene-mediated carcinogenicity have not been fully elucidated, increased reactive oxygen species (ROS) and DNA damage are implicated. Sulforaphane (SFN) induces nuclear factor erythroid 2-related factor 2 (Nrf2), which contributes to SFN-mediated protection against carcinogenesis. We exposed cultured CD-1 mouse fetal liver cells to the benzene metabolite, benzoquinone, to determine its potential to cause DNA damage and alter DNA repair. Cells were also exposed to SFN to determine potential protective effects. Initially, cells were exposed to benzoquinone to confirm increased ROS and SFN to confirm Nrf2 induction. Subsequently, cells were treated with benzoquinone (with or without SFN) and levels of ROS, 8-hydroxy-2-deoxyguanosine (8-OHdG; marker of oxidative DNA damage), gamma histone 2A variant X (γH2AX; marker of DNA double-stranded breaks; DSBs) and transcript levels of genes involved in DNA repair were measured. Benzoquinone exposure led to a significant increase in ROS, which was not prevented by pretreatment with SFN or the antioxidative enzyme, catalase. DNA damage was increased after benzoquinone exposure, which was not prevented by SFN. Benzoquinone exposure significantly decreased the transcript levels of the critical base excision repair gene, 8-oxoguanine glycosylase (Ogg1), which was not prevented by SFN. The findings of this study demonstrate for the first time that DNA damage and altered DNA repair are a consequence of benzoquinone exposure in CD-1 mouse fetal liver cells and that SFN conferred little protection in this model. Copyright © 2015 John Wiley & Sons, Ltd.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Benzoquinones; Catalase; Cell Line; Deoxyguanosine; DNA Damage; DNA Glycosylases; DNA Repair; Female; Hepatocytes; Histones; Isothiocyanates; Leukemia; Liver; Male; Mice; NAD(P)H Dehydrogenase (Quinone); NF-E2-Related Factor 2; Oxidative Stress; Reactive Oxygen Species; Sulfoxides

Chloramphenicol (CAP) was an old antimicrobial agent. However, the use of CAP is limited because of its harmful side effects, such as leukemia. The molecular mechanism through which CAP has been strongly correlated with leukemogenesis is still unclear. To elucidate the mechanism of genotoxicity, we examined DNA damage by CAP and its metabolites, nitroso-CAP (CAP-NO), N-hydroxy-CAP (CAP-NHOH), using isolated DNA. CAP-NHOH have the ability of DNA damage including 8-oxo-7,8-dihydro-2'-deoxyguanosine formation in the presence of Cu(II), which was greatly enhanced by the addition of an endogenous reductant NADH. CAP-NO caused DNA damage in the presence of Cu(II), only when reduced by NADH. NADH can non-enzymatically reduce the nitroso form to hydronitroxide radicals, resulting in enhanced generation of reactive oxygen species followed by DNA damage through the redox cycle. Furthermore, we also studied the site specificity of base lesions in DNA treated with piperidine or formamidopyrimidine-DNA glycosylase, using (32)P-5'-end-labeled DNA fragments obtained from the human tumor suppressor gene. CAP metabolites preferentially caused double base lesion, the G and C of the ACG sequence complementary to codon 273 of the p53 gene, in the presence of NADH and Cu(II). Therefore, we conclude that oxidative double base lesion may play a role in carcinogenicity of CAP.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Anti-Bacterial Agents; Cattle; Chloramphenicol; Deoxyguanosine; DNA; DNA Damage; DNA-Formamidopyrimidine Glycosylase; Free Radicals; Genes, p53; Humans; Hydroxides; Hydroxylamines; Leukemia; Oxygen; Piperidines; Reactive Oxygen Species; Spectrophotometry, Ultraviolet; Thymus Gland

Determining the level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative DNA damage biomarker, is vital to the study of clinical pathogenesis and drug toxicity. The principal limitation of capillary electrophoresis (CE) with UV detection is its low sensitivity. To overcome this shortcoming, we developed a micellar electrokinetic capillary chromatography (MEKC) with solid-phase extraction (SPE) for urinary 8-OHdG analysis. The sensitivity of MEKC-UV was improved using a reasonable UV system, injection mode, and SPE. The parameters affecting MEKC and SPE were also optimized. The calibration curve was linear within the range from 1 to 500 μg L(-1). The limits of detection and quantification were 0.27 μg L(-1) and 0.82 μg L(-1), respectively. Interday and intraday precision were both <5.6%. The recovery of 8-OHdG in urine ranged from 94.5% to 103.2%. This method was used to measure urinary 8-OHdG from eight normal children, eight newly diagnosed leukemic children, and eight leukemic children undergoing chemotherapy. The results show that the proposed method can be used to assess oxidative stress in patients and the side effects of chemotherapeutic drugs by measuring urinary 8-OHdG.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Biomarkers; Child; Child, Preschool; Chromatography, Micellar Electrokinetic Capillary; Deoxyguanosine; DNA Damage; Female; Humans; Leukemia; Male; Oxidative Stress; Solid Phase Extraction

Diagnoses of bone marrow associated malignancies such as Acute & Chronic Lymphocytic Leukemia, Acute & Chronic Myelogenous (Myeloid) Leukemia, Hodgkin's Lymphoma & Non-Hodgkin's Lymphoma, and Multiple Myeloma are often missed without a blood test. However, in 2008, Omura Y reported several newly discovered organ representation areas that exist between the lower end of the eyebrows and upper end of the upper eyelid. This space was divided into 5 organ representation areas. The first space (more than 1/4 of entire space) near the side of the face (temple) is the bone marrow representation area (BMRA). Therefore, we examined the bone marrow representation areas non-invasively using the Bi-Digital O-Ring Test (BDORT). When the small rectangular shaped part of the BMRA is strong negative (-) with more than -2, often there is a malignancy associated with bone marrow. In this area, we found 1) Integrin alpha5beta1 & Oncogen C-fos Ab2 increased very significantly between 125-300 ng BDORT units; 2) very high Chrysotile Asbestos (0.11-0.14 mg); 3) markedly reduced Acetylcholine of less than 1 ng; 4) significantly reduced telomere of less than 1 yg (= 10(-24) g); and 5) Increased 8-OH-dG (often more than 5 ng). Once the abnormal small rectangular area is localized by BDORT, by detecting the specific microscope slide which produces EMF (electromagnetic field) resonance, one can diagnose these malignancies non-invasively in about 10 minutes. When a subject has any one of the above 7 types of bone marrow associated malignancies, the 5 aforementioned abnormal parameters can be detected. When Acetylcholine is markedly reduced to 0.25 ng or less, 8-OH-dG is 10 ng or higher, and Sirtuin 1 (one of the 7 mammalian longevity genes products) in both the Hippocampus and the body is 0.025 pg or less, most of the patients have a very poor prognosis. However, we found that increasing normal cell telomere & longevity gene product Sirtuin 1 can often improve both pathology & prognosis. All measurements are in BDORT units (the weight required to produce maximum EMF resonance).

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetylcholine; Adolescent; Adult; Aged; Asbestos, Serpentine; Child; Child, Preschool; Deoxyguanosine; Electromagnetic Fields; Female; Hodgkin Disease; Humans; Infant; Integrin alpha5beta1; Leukemia; Lymphoma, Non-Hodgkin; Male; Middle Aged; Multiple Myeloma; Proto-Oncogene Proteins c-fos; Telomere

Mutations and polymorphisms of OGG1, the major mammalian 8-oxoguanine repair activity, are associated with increased risk for several cancers. Decreased 8-oxoguanine repair capacity due to variant forms of the OGG1 gene is a common feature of numerous cancer cell lines. One such cell line, human KG-1 leukemia cells, has previously been demonstrated to be deficient in the excision of 8-oxoguanine from oxidatively damaged DNA. KG-1 cells have a homozygous R229Q amino acid substitution in OGG1 that has been presumed to alter the function of OGG1 and result in elevated levels of genomic 8-oxoG and hypersensitivity to 8-hydroxydeoxyguanosine nucleoside and ionizing radiation observed in KG-1 cells.. We characterized the enzymatic activity of R229Q OGG1 and the effect of the enzyme on cell survival following treatment with DNA damaging agents.. R229Q OGG1 had activity similar to the wild-type enzyme, yet was easily heat inactivated at physiological temperature. R229Q OGG1 expressed in human cells had significantly lower activity than wild-type OGG1 and was also highly thermolabile. Expression of R229Q OGG1 sensitized KG-1 cells to killing by menadione and 8-hydroxydeoxyguanosine, but not ionizing radiation.. These results suggest that decreased 8-oxoguanine repair in KG-1 is due to thermolability of R229Q OGG1 and that the enzyme variant increases cellular susceptibility to killing resulting from oxidative DNA damage. The R229Q OGG1 variant is a validated polymorphism prevalent in world populations and not an isolated mutation in KG-1 cells, thus the R229Q OGG1 allele may be a novel marker for cancer susceptibility.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Alleles; Amino Acid Substitution; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Deoxyguanosine; DNA Damage; DNA Glycosylases; Gene Expression; Guanine; Hot Temperature; Humans; Leukemia; Polymorphism, Genetic; Radiation, Ionizing; Vitamin K 3; Vitamins

8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG), the most common oxidatively modified nucleoside, is released from oxidized DNA and oxidized nucleotide pool. However, little information is available regarding the metabolic pathway of free 8-oxo-dG. In this study, we generated radiolabeled 8-oxo-dG to track its metabolic fate. We report that 8-oxo-dG is neither phosphorylated to 8-oxo-dGMP nor degraded to the free base, 8-oxo-7,8-dihydroguanine (8-oxo-Gua), indicating that 8-oxo-dG is not a substrate for nucleotide synthesis. This result was confirmed by the finding that no radioactivity was detected in the DNA of U937 cells after incubating the cells with radiolabeled 8-oxo-dG. These observations indicate that 8-oxo-dG produced by oxidative stress is not reutilized for DNA synthesis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Cell Line, Tumor; DNA; DNA Replication; Guanine; Humans; Leukemia; Oxidative Stress

Our previous study showed that KG-1, a human acute leukemia cell line, has mutational loss of 8-oxoguanine (8-hydroxyguanine; oh(8)Gua) glycosylase 1 (OGG1) activity and that its viability is severely affected by 8-hydroxydeoxyguanosine (8-oxodeoxyguanosine; oh(8)dG). In the present study, the nature of the killing action of oh(8)dG on KG-1 was investigated. Signs observed in oh(8)dG-treated KG-1 cells indicated that death was due to apoptosis, as demonstrated by: increased sub-G(1) hypodiploid (apoptotic) cells, DNA fragmentation, and apoptotic body formation; loss of mitochondrial transmembrane potential, the release of cytochrome c from mitochondria into the cytosol, and the down-regulation of bcl-2; and the activation of caspases 8, 9, and 3, and the efficient inhibition of the apoptotic process by caspases inhibitors. This apoptosis appears not to be associated with Fas/Fas ligand because the expressions of these proteins were unchanged. Apoptotic KG-1 cells showed a high concentration of oh(8)Gua in DNA. Moreover, the increased concentration of oh(8)Gua in DNA, and the apoptotic process were not suppressed by the antioxidant, N-acetylcysteine, and thus the process is independent of reactive oxygen species. Of the 18 cancer cell lines treated with oh(8)dG, 3 cell lines (H9, CEM-CM3, and Molt-4) were found to be committed to apoptosis, and all of these showed very low OGG1 activity and a marked increase in the concentration of oh(8)Gua in DNA. These observations indicate that in addition to its mutagenic action, oh(8)Gua in DNA disturbs cell viability by inducing apoptosis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Apoptosis; Cell Division; Cell Line, Tumor; Deoxyguanosine; DNA; DNA-Formamidopyrimidine Glycosylase; Escherichia coli Proteins; Fas Ligand Protein; fas Receptor; Guanine; Humans; Leukemia; Membrane Glycoproteins; Reactive Oxygen Species

The active involvement of physical exercise in the evolution of a variety of cancers is well documented. However, its role in solid leukemia tumor development is essentially unknown. Solid leukemia tumor cells were transplanted into 21 hybrid BDF1 control mice, exercise-trained mice that did not exercise during leukemia and exercise-trained mice that exercised during leukemia. The tumor size of the continuously exercising group was ~50% of that of control and exercise-terminated animals 18 days after the transplantation. The activity of antioxidant enzymes and the levels of lipid peroxidation and 8-hydroxy-2'-deoxyguanosine were not different in the tumors of the three groups. The level of carbonylated proteins was smaller in tumors of continuously exercising animals. The mutant form of cell regulatory protein p53 and vascular endothelial growth factor were present in similar amounts in the tumor cells of each group. On the other hand, the protooncogene Ras and I-kappaB proteins were present in higher concentrations in tumors of continuously exercising rats. The present data suggest that exercise during leukemia attenuates the development of tumors in mice. The selective alteration of regulatory proteins might play a role in the beneficial effects of exercise during leukemia.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Deoxyguanosine; Immunoblotting; Leukemia; Lipid Peroxidation; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Neoplasm Transplantation; Physical Conditioning, Animal; Time Factors; Tumor Cells, Cultured; Tumor Suppressor Protein p53

We tested the cytotoxic action of 8-hydroxyguanine (8ohG) by observing the viability of several leukemic cell lines (KG-1, U937, Jurkat and K 562) in the presence of 8-hydroxydeoxyguanosine (8ohdG), a nucleoside of 8ohG. It was found that 8ohdG showed cytotoxic action only to KG-1 and that only KG-1 showed a homozygous arginine 209 to glutamine mutation in the hOGG1 gene with an almost negligible hOGG1 enzyme activity. Possibly, the selective cytotoxicity in 8ohdG to KG-1 may be due to its low capacity to cope with an increase in the 8ohG level in DNA resulting from the incorporation of 8ohdG present in the culture media. The mutational impairment of hOGG1 in KG-1 is the first report in leukemic cell lines. Using KG-1 with impaired hOGG1, we demonstrated cytotoxicity of 8ohdG probably due to its incorporation into cellular DNA. This new property of KG-1 may allow it to serve as an useful tool for studies of OGG1, oxidative DNA damage and the cytotoxic action of 8ohG. Oncogene (2000) 19, 4476 - 4479.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Cell Death; Deoxyguanosine; DNA-Formamidopyrimidine Glycosylase; Humans; Leukemia; N-Glycosyl Hydrolases; Point Mutation; Tumor Cells, Cultured