Karol Bialkowski - Profile on Academia.edu (original) (raw)
Papers by Karol Bialkowski
[Metabolism of phosphorylated derivatives of 8-oxo-2'-deoxyguanosine]
PubMed, 1997
Chemical Research in Toxicology, Mar 17, 2010
Recommendations for standardised description of, and nomenclature concerning, oxidatively damaged... more Recommendations for standardised description of, and nomenclature concerning, oxidatively damaged nucleobases in DNA.
[Reactive oxygen species and gene expression regulation]
Postepy biochemii, 1996
Biologically relevant oxidants and terminology, classification and nomenclature of oxidatively generated damage to nucleobases and 2-deoxyribose in nucleic acids
PMC, Apr 1, 2012
Acta Biochimica Polonica, Oct 24, 2022
Our goal was to verify the proteolytic mode of action and activity levels among several commercia... more Our goal was to verify the proteolytic mode of action and activity levels among several commercial cosmetic facial peels advertised by manufacturers as "enzymatic". Eleven enzyme peels were analyzed for their proteolytic activity against casein as a generic substrate and compared to the activity found in pineapple and papaya fruits. The highest specific protease activity was observed in the flesh of a pineapple (5.88 U/g). Only two products demonstrated sufficient activity (0.924 and 0.238 U/g) to be called "enzyme peels". Three products showed trace activity (0.023-0.125 U/g), albeit too low to exert a significant exfoliating effect. Six preparations had no detectable enzyme activity.
Free Radical Biology and Medicine, 2003
The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up to resolve problems ... more The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up to resolve problems in the measurement of DNA oxidation that have resulted in varying estimates of the extent of this damage in humans. HeLa cells, sent to members for analysis, were either untreated, or treated with light in the presence of a photosensitizer to induce different amounts of 8-oxo-7,8-dihydroguanine (8-oxoGua) in DNA. Laboratories employing HPLC with electrochemical detection were able to measure the induced damage with similar efficiency; dose response gradients for seven of the eight sets of results were almost identical. GC-MS and HPLC-MS/MS, employed in three laboratories, did not convincingly detect the dose response. An alternative approach to measuring base oxidation employs the enzyme formamidopyrimidine DNA N-glycosylase (FPG) to convert 8-oxoGua to strand breaks, which are then measured by alkaline unwinding, alkaline elution, or the comet assay. Ten laboratories used this approach; five were able to detect the dose response in cells treated with photosensitizer plus light (at lower doses than for chromatographic methods, because the enzymic methods are more sensitive and less prone to spurious oxidation). Median values for 8-oxoGua (or FPG-sensitive sites) in untreated cells were 4.01 per 10 6 guanines for chromatographic methods, and 0.53 per 10 6 guanines for techniques based on FPG.
Free Radical Research, 2002
The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up in 1997 to resolve m... more The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up in 1997 to resolve methodological problems and to reach agreement on the basal level of 8-oxo-2 0-deoxyguanosine (8-oxodG) in biological samples. In the present ESCODD trial 6 samples of 8-oxodGcontaining oligonucleotides with different ratios of 8-oxodG/2 0-deoxyadenosine (dAdo) were sent to 25 laboratories throughout Europe. The methods used were HPLC with electrochemical detection (amperometric or coulometric), GC-MS or LC-MS-MS. The LC-MS-MS and the coulometric HPLC analyses gave 8-oxodG concentrations within 53 and 73% of expected values, respectively, whereas the amperometric HPLC and GC-MS consistently overestimated the 8-oxodG concentration by several fold. As the oligonucleotides contained no 2 0-deoxyguanosine (dGuo), this was not due to artificial oxidation. On the contrary, in most cases the concentrations of dAdo and thymidine (dThd), used as estimates for non-oxidised DNA bases were underestimated, though a few laboratories overestimated the lowest concentration samples containing 8 and 20 mM, respectively. In onethird of the reported results, the ratio of 8-oxodG/10 5 dAdo was within 25% of the calculated value in the oligonucleotide samples and in half of the results the coefficient of variation in duplicate samples was less than 10%. The coefficients of variation were higher for the dAdo concentrations than for 8-oxodG. Our findings strongly indicate that careful quality control must be applied to the analytical procedures for 8-oxodG and very importantly also to the procedures for non-modified 2 0-deoxyribonucleosides. We recommend the use of synthetic oligonucleotides for this purpose.
Improved high-performance liquid chromatographic method for N-acetylgalactosamine-4-sulfate sulfatase (arylsulfatase B) activity determination using uridine diphospho-N-acetylgalactosamine-4-sulfate
Journal of Chromatography B Biomedical Sciences and Applications, Aug 1, 1997
Oxidative DNA damage in cancer patients: a cause or a consequence of the disease development?
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 2003
A wide variety of oxidative DNA lesions are present in living cells. One of the best known lesion... more A wide variety of oxidative DNA lesions are present in living cells. One of the best known lesions of this type is 8-oxoguanine (8-oxoGua) which has been shown to have mutagenic properties. An influence of antioxidative vitamins and labile iron pool on the background level of 8-oxoGua in cellular DNA is discussed and oxidative damage to free nucleotide pool as a possible source of 8-oxo-2'-deoxyguanosine in DNA and urine is described. An involvement of 8-oxoGua in the origin and/or progression of cancer is reviewed. It is concluded that a severe oxidative stress manifested as a high level of 8-oxoGua in cellular DNA as well as in urine of cancer patients is a consequence of development of many types of cancer. Although at present it is impossible to answer directly the question concerning involvement of oxidative DNA damage in cancer etiology it is likely that oxidative DNA base modifications may serve as a source of mutations that initiate carcinogenesis (i.e. they may be causal factors responsible for the process).
Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 1999
In the present study we measured the amount of 8-oxo-2 '-deoxyguanosine (8-oxo-dG) in DNA isolate... more In the present study we measured the amount of 8-oxo-2 '-deoxyguanosine (8-oxo-dG) in DNA isolated from lymphocytes of arteriosclerotic patients undergoing ozonetherapy. Treatment of the patients with therapeutic concentration of ozone caused a significant increase over the control value in the amount of 8-oxo-dG of DNA isolated from their lymphocytes. However, only three out of six patients examined responded positively to the treatment in terms of the base damage. The increases varied among patients, and were in the range of 100-450%. This interindividual difference may at least be partly explained by recently demonstrated heritable susceptibility to ozone.
Molecular Pharmacology, 1997
Anthracycline derivatives have been widely used in the treatment of several types of human malign... more Anthracycline derivatives have been widely used in the treatment of several types of human malignancies. Cytotoxicity of these drugs has been attributed to inhibition of topoisomerase II as well as intracellular production of free radicals. In our work we used a gas chromatography/mass spectrometry technique to study free radical-induced DNA base modifications in chromatin isolated from lymphocytes of cancer patients who received chemotherapy with epirubicin (one of anthracycline's antitumor derivatives). The anticancer therapy caused signifi
Cancer Letters, 1996
We analyzed the level of %oxo-2'-deoxyguanosine in lymphocytes DNA of cancer patients undergoing ... more We analyzed the level of %oxo-2'-deoxyguanosine in lymphocytes DNA of cancer patients undergoing radiotherapy. The results of this work indicate that exposure of cancer patients to therapeutic doses of ionizing radiation causes significant increase of the amount of 8-oxo-dG in DNA isolated from their lymphocytes.
Acta Chromatographica, 2009
In this paper we present a comprehensive object categorization and classification system, of grea... more In this paper we present a comprehensive object categorization and classification system, of great importance for mobile manipulation applications in indoor environments. In detail, we tackle the problem of recognizing everyday objects that are useful for a personal robotic assistant in fulfilling its tasks, using a hierarchical multi-modal 3D-2D processing and classification system. The acquired 3D data is used to estimate geometric labels (plane, cylinder, edge, rim, sphere) at each voxel cell using the Radius-based Surface Descriptor (RSD). Then, we propose the use of a Global RSD feature (GRSD) to categorize point clusters that are geometrically identical into one of the object categories. Once a geometric category and a 3D position is obtained for each object cluster, we extract the region of interest in the camera image and compute a SURF-based feature vector for it. Thus we obtain the exact object instance and the orientation around the object's upright axis from the appearance. The resultant system provides a hierarchical categorization of objects into basic classes from their geometry and identifies objects and their poses based on their appearance, with near real-time performance. We validate our approach on an extensive database of objects that we acquired using real sensing devices, and on both unseen views and unseen objects.
Acta Biochimica Polonica, 1999
In this study we investigated the level of 8-oxo-2'-deoxyguanosine (8-oxodG) in DNA of Cardam... more In this study we investigated the level of 8-oxo-2'-deoxyguanosine (8-oxodG) in DNA of Cardamine pratensis plants subjected to different growth conditions trying to answer the question whether factors like light and water accessibility or low temperature may have an impact on the total DNA oxidative damage. The level of this modified nucleoside was determined using HPLC coupled to UV absorbance and electrochemical detection (HPLC-UV-EC). We did not observe any statistically significant differences in 8-oxodG level between DNA of etiolated and light exposed plants as well as between DNA of regularly watered and drought-subjected plants. In contrast, we have shown that chilling (1 degree C for 28 h) brings about the increase of 8-oxodG level in DNA.
Studies on Oxidative Mechanisms of Metal-Induced Carcinogenesis
Advances in DNA Damage and Repair, 1999
Two ways by which carcinogenic metals, such as Ni(II), Co(II), Cu(II), or Cd(II), may promote oxi... more Two ways by which carcinogenic metals, such as Ni(II), Co(II), Cu(II), or Cd(II), may promote oxidative DNA damage, including direct effects consisting of activation of oxygen species and mediation of their attack on DNA, and indirect effects through suppression of cellular antimutagenic defenses, are discussed. The mechanisms of the direct attack may involve chelation of a metal by nuclear proteins, especially the histones and protamines, and activation of metabolic oxygen species by the resulting metal complexes at close proximity to DNA. We found that human protamine HP2 has a typical binding motif for Ni(II) and Cu(II), Arg-Thr-His-, at its N-terminus. A synthetic pentadecapeptide modeling this terminus formed strong chelates with these metals and, in addition, enhanced oxidative DNA damage by Ni(II) plus H2O2, but suppressed, though not completely, the damage by Cu(II) plus H2O2. Since protamines carry DNA in the sperm, the observed DNA damage may have spermicidal or transgenerational carcinogenic effects in man exposed to metals, as observed epidemiologically. The indirect effects of metals on DNA may involve inhibition of 8-oxo-dGTPases, a class of enzymes preventing incorporation of the 8-oxoguanine lesion from oxidatively-damaged deoxynucleotide pool into DNA. Cd(II) and Cu(II), and to a limited extent also Ni(II) and Co(II), were found to in vitro inhibit the enzymatic activity of a bacterial (MutT) and human (MTH1) 8-oxo dGTPases. This may allow redox-inactive metals, such as Cd(II), to introduce the promutagenic 8-oxoguanine lesion from endogenously damaged 8-oxo-dGTP into DNA.
Zeitschrift für Naturforschung C - A Journal of Biosciences, Feb 1, 1996
8-Oxo-2'-deoxyguanosine, 8-Oxoguanine, 8-Hydroxyguanine, Base Modification, DNA Oxidative Damage ... more 8-Oxo-2'-deoxyguanosine, 8-Oxoguanine, 8-Hydroxyguanine, Base Modification, DNA Oxidative Damage The influence of 2'-deoxyguanosine (dG) oxidation at the C-8 position on N-glycosidic bond stability was in vestigated. A kinetic analysis of dG and 8-oxo-2'-deoxyguanosine (8-oxodG) depurination reactions was carried out in water solutions at pH ranging from 2 to 7.4 and temperature of 100 °C. The results indicate that N-glyco sidic bond of 8-oxodG is significantly more stable in comparison with dG at any pH applied. At pH 5.1 hy drolysis rate of dG is 4.5-fold higher than that for 8-oxodG. The chemical stability of the modified nucleo side in oxidatively damaged DNA is one of important factors contributing to its mutagenic potential. Results of our experiments indicate that 8-oxodG, potentially mutagenic and carcinogenic nucleoside, is hardly suscep tible to spontaneous depurination and its removal from cellular DNA depends mostly on the activity of DNA repair enzymes.
Specific 8-oxo-dGTPase activity of MTH1 (NUDT1) protein as a quantitative marker and prognostic factor in human colorectal cancer
Free Radical Biology and Medicine
A profile of 8-oxo-dGTPase activities in the NCI-60 human cancer panel: Meta-analytic insight into the regulation and role of MTH1 (NUDT1) gene expression in carcinogenesis
Free Radical Biology and Medicine
PLOS ONE
Active demethylation of 5-methylcytosine moiety in DNA occurs by its sequential oxidation to 5-hy... more Active demethylation of 5-methylcytosine moiety in DNA occurs by its sequential oxidation to 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxycytosine, catalysed by enzymes of the Ten-Eleven Translocation family proteins (TETs 1, 2 and 3). Here we analyzed for the first time all the intermediate products of DNA demethylation pathway in the form of deoxynucleosides (5-methyl-2 0-deoxycytidine, 5-(hydroxymethyl)-2 0-deoxycytidine, 5-formyl-2 0-deoxycytidine and 5-carboxy-2 0-deoxycytidine as well as 5-(hydroxymethyl)-2 0-deoxyuridine) using automated isotope-dilution online two-dimensional ultraperformance liquid chromatography with tandem mass spectrometry. DNA was isolated from human malignant cell lines of colon adenocarcinoma (HCT 116), melanoma (Me45), myelogenous leukemia bone marrow blasts (K562), EBV-positive Burkitt's lymphoma lymphoblasts (Raji), EBV-negative Burkitt's lymphoma lymphoblasts (male-CA46 and female-ST486), as well as normal neonatal dermal fibroblasts (NHDF-Neo). The expression levels of TET1, TET2, TET3, SMUG1, and TDG genes were also assayed by RT-qPCR. Our results show a global erasure of 5-hydroxymethyl-2 0-deoxycytidine and 5-carboxy-2 0-deoxycytidine in DNA of cultured cells compared with DNA from primary malignant tissue. Moreover, malignant cells in culture have a quite different DNA epigenetic profile than cultured normal cells, and different types of malignant cells display different and characteristic profiles of DNA epigenetic marks. Similar analyses of a broader spectrum of epigenetic modifications, not restricted to 5-methyl-2 0-deoxycytidine, could lead to PLOS ONE |
[Metabolism of phosphorylated derivatives of 8-oxo-2'-deoxyguanosine]
PubMed, 1997
Chemical Research in Toxicology, Mar 17, 2010
Recommendations for standardised description of, and nomenclature concerning, oxidatively damaged... more Recommendations for standardised description of, and nomenclature concerning, oxidatively damaged nucleobases in DNA.
[Reactive oxygen species and gene expression regulation]
Postepy biochemii, 1996
Biologically relevant oxidants and terminology, classification and nomenclature of oxidatively generated damage to nucleobases and 2-deoxyribose in nucleic acids
PMC, Apr 1, 2012
Acta Biochimica Polonica, Oct 24, 2022
Our goal was to verify the proteolytic mode of action and activity levels among several commercia... more Our goal was to verify the proteolytic mode of action and activity levels among several commercial cosmetic facial peels advertised by manufacturers as "enzymatic". Eleven enzyme peels were analyzed for their proteolytic activity against casein as a generic substrate and compared to the activity found in pineapple and papaya fruits. The highest specific protease activity was observed in the flesh of a pineapple (5.88 U/g). Only two products demonstrated sufficient activity (0.924 and 0.238 U/g) to be called "enzyme peels". Three products showed trace activity (0.023-0.125 U/g), albeit too low to exert a significant exfoliating effect. Six preparations had no detectable enzyme activity.
Free Radical Biology and Medicine, 2003
The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up to resolve problems ... more The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up to resolve problems in the measurement of DNA oxidation that have resulted in varying estimates of the extent of this damage in humans. HeLa cells, sent to members for analysis, were either untreated, or treated with light in the presence of a photosensitizer to induce different amounts of 8-oxo-7,8-dihydroguanine (8-oxoGua) in DNA. Laboratories employing HPLC with electrochemical detection were able to measure the induced damage with similar efficiency; dose response gradients for seven of the eight sets of results were almost identical. GC-MS and HPLC-MS/MS, employed in three laboratories, did not convincingly detect the dose response. An alternative approach to measuring base oxidation employs the enzyme formamidopyrimidine DNA N-glycosylase (FPG) to convert 8-oxoGua to strand breaks, which are then measured by alkaline unwinding, alkaline elution, or the comet assay. Ten laboratories used this approach; five were able to detect the dose response in cells treated with photosensitizer plus light (at lower doses than for chromatographic methods, because the enzymic methods are more sensitive and less prone to spurious oxidation). Median values for 8-oxoGua (or FPG-sensitive sites) in untreated cells were 4.01 per 10 6 guanines for chromatographic methods, and 0.53 per 10 6 guanines for techniques based on FPG.
Free Radical Research, 2002
The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up in 1997 to resolve m... more The European Standards Committee on Oxidative DNA Damage (ESCODD) was set up in 1997 to resolve methodological problems and to reach agreement on the basal level of 8-oxo-2 0-deoxyguanosine (8-oxodG) in biological samples. In the present ESCODD trial 6 samples of 8-oxodGcontaining oligonucleotides with different ratios of 8-oxodG/2 0-deoxyadenosine (dAdo) were sent to 25 laboratories throughout Europe. The methods used were HPLC with electrochemical detection (amperometric or coulometric), GC-MS or LC-MS-MS. The LC-MS-MS and the coulometric HPLC analyses gave 8-oxodG concentrations within 53 and 73% of expected values, respectively, whereas the amperometric HPLC and GC-MS consistently overestimated the 8-oxodG concentration by several fold. As the oligonucleotides contained no 2 0-deoxyguanosine (dGuo), this was not due to artificial oxidation. On the contrary, in most cases the concentrations of dAdo and thymidine (dThd), used as estimates for non-oxidised DNA bases were underestimated, though a few laboratories overestimated the lowest concentration samples containing 8 and 20 mM, respectively. In onethird of the reported results, the ratio of 8-oxodG/10 5 dAdo was within 25% of the calculated value in the oligonucleotide samples and in half of the results the coefficient of variation in duplicate samples was less than 10%. The coefficients of variation were higher for the dAdo concentrations than for 8-oxodG. Our findings strongly indicate that careful quality control must be applied to the analytical procedures for 8-oxodG and very importantly also to the procedures for non-modified 2 0-deoxyribonucleosides. We recommend the use of synthetic oligonucleotides for this purpose.
Improved high-performance liquid chromatographic method for N-acetylgalactosamine-4-sulfate sulfatase (arylsulfatase B) activity determination using uridine diphospho-N-acetylgalactosamine-4-sulfate
Journal of Chromatography B Biomedical Sciences and Applications, Aug 1, 1997
Oxidative DNA damage in cancer patients: a cause or a consequence of the disease development?
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 2003
A wide variety of oxidative DNA lesions are present in living cells. One of the best known lesion... more A wide variety of oxidative DNA lesions are present in living cells. One of the best known lesions of this type is 8-oxoguanine (8-oxoGua) which has been shown to have mutagenic properties. An influence of antioxidative vitamins and labile iron pool on the background level of 8-oxoGua in cellular DNA is discussed and oxidative damage to free nucleotide pool as a possible source of 8-oxo-2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-deoxyguanosine in DNA and urine is described. An involvement of 8-oxoGua in the origin and/or progression of cancer is reviewed. It is concluded that a severe oxidative stress manifested as a high level of 8-oxoGua in cellular DNA as well as in urine of cancer patients is a consequence of development of many types of cancer. Although at present it is impossible to answer directly the question concerning involvement of oxidative DNA damage in cancer etiology it is likely that oxidative DNA base modifications may serve as a source of mutations that initiate carcinogenesis (i.e. they may be causal factors responsible for the process).
Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 1999
In the present study we measured the amount of 8-oxo-2 '-deoxyguanosine (8-oxo-dG) in DNA isolate... more In the present study we measured the amount of 8-oxo-2 '-deoxyguanosine (8-oxo-dG) in DNA isolated from lymphocytes of arteriosclerotic patients undergoing ozonetherapy. Treatment of the patients with therapeutic concentration of ozone caused a significant increase over the control value in the amount of 8-oxo-dG of DNA isolated from their lymphocytes. However, only three out of six patients examined responded positively to the treatment in terms of the base damage. The increases varied among patients, and were in the range of 100-450%. This interindividual difference may at least be partly explained by recently demonstrated heritable susceptibility to ozone.
Molecular Pharmacology, 1997
Anthracycline derivatives have been widely used in the treatment of several types of human malign... more Anthracycline derivatives have been widely used in the treatment of several types of human malignancies. Cytotoxicity of these drugs has been attributed to inhibition of topoisomerase II as well as intracellular production of free radicals. In our work we used a gas chromatography/mass spectrometry technique to study free radical-induced DNA base modifications in chromatin isolated from lymphocytes of cancer patients who received chemotherapy with epirubicin (one of anthracycline's antitumor derivatives). The anticancer therapy caused signifi
Cancer Letters, 1996
We analyzed the level of %oxo-2'-deoxyguanosine in lymphocytes DNA of cancer patients undergoing ... more We analyzed the level of %oxo-2'-deoxyguanosine in lymphocytes DNA of cancer patients undergoing radiotherapy. The results of this work indicate that exposure of cancer patients to therapeutic doses of ionizing radiation causes significant increase of the amount of 8-oxo-dG in DNA isolated from their lymphocytes.
Acta Chromatographica, 2009
In this paper we present a comprehensive object categorization and classification system, of grea... more In this paper we present a comprehensive object categorization and classification system, of great importance for mobile manipulation applications in indoor environments. In detail, we tackle the problem of recognizing everyday objects that are useful for a personal robotic assistant in fulfilling its tasks, using a hierarchical multi-modal 3D-2D processing and classification system. The acquired 3D data is used to estimate geometric labels (plane, cylinder, edge, rim, sphere) at each voxel cell using the Radius-based Surface Descriptor (RSD). Then, we propose the use of a Global RSD feature (GRSD) to categorize point clusters that are geometrically identical into one of the object categories. Once a geometric category and a 3D position is obtained for each object cluster, we extract the region of interest in the camera image and compute a SURF-based feature vector for it. Thus we obtain the exact object instance and the orientation around the object's upright axis from the appearance. The resultant system provides a hierarchical categorization of objects into basic classes from their geometry and identifies objects and their poses based on their appearance, with near real-time performance. We validate our approach on an extensive database of objects that we acquired using real sensing devices, and on both unseen views and unseen objects.
Acta Biochimica Polonica, 1999
In this study we investigated the level of 8-oxo-2'-deoxyguanosine (8-oxodG) in DNA of Cardam... more In this study we investigated the level of 8-oxo-2'-deoxyguanosine (8-oxodG) in DNA of Cardamine pratensis plants subjected to different growth conditions trying to answer the question whether factors like light and water accessibility or low temperature may have an impact on the total DNA oxidative damage. The level of this modified nucleoside was determined using HPLC coupled to UV absorbance and electrochemical detection (HPLC-UV-EC). We did not observe any statistically significant differences in 8-oxodG level between DNA of etiolated and light exposed plants as well as between DNA of regularly watered and drought-subjected plants. In contrast, we have shown that chilling (1 degree C for 28 h) brings about the increase of 8-oxodG level in DNA.
Studies on Oxidative Mechanisms of Metal-Induced Carcinogenesis
Advances in DNA Damage and Repair, 1999
Two ways by which carcinogenic metals, such as Ni(II), Co(II), Cu(II), or Cd(II), may promote oxi... more Two ways by which carcinogenic metals, such as Ni(II), Co(II), Cu(II), or Cd(II), may promote oxidative DNA damage, including direct effects consisting of activation of oxygen species and mediation of their attack on DNA, and indirect effects through suppression of cellular antimutagenic defenses, are discussed. The mechanisms of the direct attack may involve chelation of a metal by nuclear proteins, especially the histones and protamines, and activation of metabolic oxygen species by the resulting metal complexes at close proximity to DNA. We found that human protamine HP2 has a typical binding motif for Ni(II) and Cu(II), Arg-Thr-His-, at its N-terminus. A synthetic pentadecapeptide modeling this terminus formed strong chelates with these metals and, in addition, enhanced oxidative DNA damage by Ni(II) plus H2O2, but suppressed, though not completely, the damage by Cu(II) plus H2O2. Since protamines carry DNA in the sperm, the observed DNA damage may have spermicidal or transgenerational carcinogenic effects in man exposed to metals, as observed epidemiologically. The indirect effects of metals on DNA may involve inhibition of 8-oxo-dGTPases, a class of enzymes preventing incorporation of the 8-oxoguanine lesion from oxidatively-damaged deoxynucleotide pool into DNA. Cd(II) and Cu(II), and to a limited extent also Ni(II) and Co(II), were found to in vitro inhibit the enzymatic activity of a bacterial (MutT) and human (MTH1) 8-oxo dGTPases. This may allow redox-inactive metals, such as Cd(II), to introduce the promutagenic 8-oxoguanine lesion from endogenously damaged 8-oxo-dGTP into DNA.
Zeitschrift für Naturforschung C - A Journal of Biosciences, Feb 1, 1996
8-Oxo-2'-deoxyguanosine, 8-Oxoguanine, 8-Hydroxyguanine, Base Modification, DNA Oxidative Damage ... more 8-Oxo-2'-deoxyguanosine, 8-Oxoguanine, 8-Hydroxyguanine, Base Modification, DNA Oxidative Damage The influence of 2'-deoxyguanosine (dG) oxidation at the C-8 position on N-glycosidic bond stability was in vestigated. A kinetic analysis of dG and 8-oxo-2'-deoxyguanosine (8-oxodG) depurination reactions was carried out in water solutions at pH ranging from 2 to 7.4 and temperature of 100 °C. The results indicate that N-glyco sidic bond of 8-oxodG is significantly more stable in comparison with dG at any pH applied. At pH 5.1 hy drolysis rate of dG is 4.5-fold higher than that for 8-oxodG. The chemical stability of the modified nucleo side in oxidatively damaged DNA is one of important factors contributing to its mutagenic potential. Results of our experiments indicate that 8-oxodG, potentially mutagenic and carcinogenic nucleoside, is hardly suscep tible to spontaneous depurination and its removal from cellular DNA depends mostly on the activity of DNA repair enzymes.
Specific 8-oxo-dGTPase activity of MTH1 (NUDT1) protein as a quantitative marker and prognostic factor in human colorectal cancer
Free Radical Biology and Medicine
A profile of 8-oxo-dGTPase activities in the NCI-60 human cancer panel: Meta-analytic insight into the regulation and role of MTH1 (NUDT1) gene expression in carcinogenesis
Free Radical Biology and Medicine
PLOS ONE
Active demethylation of 5-methylcytosine moiety in DNA occurs by its sequential oxidation to 5-hy... more Active demethylation of 5-methylcytosine moiety in DNA occurs by its sequential oxidation to 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxycytosine, catalysed by enzymes of the Ten-Eleven Translocation family proteins (TETs 1, 2 and 3). Here we analyzed for the first time all the intermediate products of DNA demethylation pathway in the form of deoxynucleosides (5-methyl-2 0-deoxycytidine, 5-(hydroxymethyl)-2 0-deoxycytidine, 5-formyl-2 0-deoxycytidine and 5-carboxy-2 0-deoxycytidine as well as 5-(hydroxymethyl)-2 0-deoxyuridine) using automated isotope-dilution online two-dimensional ultraperformance liquid chromatography with tandem mass spectrometry. DNA was isolated from human malignant cell lines of colon adenocarcinoma (HCT 116), melanoma (Me45), myelogenous leukemia bone marrow blasts (K562), EBV-positive Burkitt's lymphoma lymphoblasts (Raji), EBV-negative Burkitt's lymphoma lymphoblasts (male-CA46 and female-ST486), as well as normal neonatal dermal fibroblasts (NHDF-Neo). The expression levels of TET1, TET2, TET3, SMUG1, and TDG genes were also assayed by RT-qPCR. Our results show a global erasure of 5-hydroxymethyl-2 0-deoxycytidine and 5-carboxy-2 0-deoxycytidine in DNA of cultured cells compared with DNA from primary malignant tissue. Moreover, malignant cells in culture have a quite different DNA epigenetic profile than cultured normal cells, and different types of malignant cells display different and characteristic profiles of DNA epigenetic marks. Similar analyses of a broader spectrum of epigenetic modifications, not restricted to 5-methyl-2 0-deoxycytidine, could lead to PLOS ONE |