5 Hydroxymethyluracil - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

5 Hydroxymethyluracil

The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform

5 Hydroxymethyluracil – Free Register to Access Experts & Abstracts

Ryszard Olinski – One of the best experts on this subject based on the ideXlab platform.

  • vitamin c enhances substantially formation of 5 Hydroxymethyluracil in cellular dna
    Free Radical Biology and Medicine, 2016
    Co-Authors: Martyna Modrzejewska, Daniel Gackowski, Marta Starczak, Maciej Gawronski, Magdalena Skonieczna, Ewelina Zarakowska, Marek Foksinski, Joanna Rzeszowskawolny, Ryszard Olinski
    Abstract:

    The most plausible mechanism behind active demethylation of 5-methylcytosine involves TET proteins which participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine; the latter is further oxidized to 5-formylcytosine and 5-carboxycytosine. 5Hydroxymethyluracil can be also generated from thymine in a TET-catalyzed process. Ascorbate was previously demonstrated to enhance generation of 5-hydroxymethylcytosine in cultured cells. The aim of this study was to determine the levels of the abovementioned TET-mediated oxidoxidation products of 5-methylcytosine and thymine after addition of ascorbate, using an isotope-dilution automated online two-dimensional ultra-performance liquid chrochromatography with electrospray ioniionization tandem mass spectrometry. Intracellular concentration of ascorbate was determined by means of ultra-performance liquid chrochromatography with UV detection. Irrespective of its concentration in culture medium (10-100µM) and inside the cell, ascorbate stimulated a moderate (2- to 3-fold) albeit persistent (up to 96-h) increase in the level of 5-hydroxymethylcytosine. However, exposure of cells to higher concentrations of ascorbate (100µM or 1mM) stimulated a substantial increase in 5-formylcytosine and 5-carboxycytosine levels. Moreover, for the first time we demonstrated a spectacular (up to 18.5-fold) increase in 5Hydroxymethyluracil content what, in turn, suggests that TET enzymes contributed to the presence of the modification in cellular DNA. These findings suggest that physiological concentrations of ascorbate in human serum (10-100µM) are sufficient to maintain a stable level of 5-hydroxymethylcytosine in cellular DNA. However, markedly higher concentrations of ascorbate (ca. 100µM in the cell milieu or ca. 1mM inside the cell) were needed to obtain a sustained increase in 5-formylcytosine, 5-carboxycytosine and 5Hydroxymethyluracil levels. Such feedback to elevated concentrations of ascorbate may reflect adaptation of the cell to environmental conditions.

  • enigmatic 5 Hydroxymethyluracil oxidatively modified base epigenetic mark or both
    Mutation Research-reviews in Mutation Research, 2016
    Co-Authors: Ryszard Olinski, Marta Starczak, Daniel Gackowski
    Abstract:

    The aim of this review is to describe the reactions which lead to generation of 5Hydroxymethyluracil, as well as the repair processes involved in its removal from DNA, and its level in various cells and urine. 5Hydroxymethyluracil may be formed during the course of the two processes: oxidation/hydroxylation of thymine with resultant formation of 5Hydroxymethyluracil paired with adenine (produced by reactive oxygen species), and reacting of reactive oxygen species with 5-methylcytosine forming 5-hydroxymethylcytosine, followed by its deamination to 5Hydroxymethyluracil mispaired with guanine. However, other, perhaps enzymatic, mechanism(s) may be involved in formation of 5Hydroxymethyluracil mispaired with guanine. Indeed, this mispair may be also formed as a result of deamination of 5-hydroxymethylcytosine, recently described “sixth” DNA base. It was demonstrated that 5Hydroxymethyluracil paired with adenine can be also generated by TET enzymes from thymine during mouse embryonic cell differentiation. Therefore, it is possible that 5Hydroxymethyluracil is epigenetic mark. The level of 5Hydroxymethyluracil in various somatic tissues is relatively stable and resembles that observed in lymphocytes, about 0.5/10(6) dN in human colon, colorectal cancer as well as various rat and porcine tissues. Experimental evidence suggests that SMUG1 and TDG are main enzymes involved in removal of 5Hydroxymethyluracil from DNA. 5Hydroxymethyluracil, in form of 5-hydroxymethyluridine, was also detected in rRNA, and together with SMUG1 may play a role in rRNA quality control. To summarize, 5Hydroxymethyluracil is with no doubt a product of both enzymatic and reactive oxygen species-induced reaction. This modification may probably serve as an epigenetic mark, providing additional layer of information encoded within the genome. However, the pool of 5Hydroxymethyluracil generated as a result of oxidative stress is also likely to disturb physiological epigenetic processes, and as such may be defined as a lesion. Altogether this suggests that 5Hydroxymethyluracil may be either a regulatory or erroneous compound.

  • tissue specific differences in dna modifications 5 hydroxymethylcytosine 5 formylcytosine 5 carboxylcytosine and 5 Hydroxymethyluracil and their interrelationships
    PLOS ONE, 2015
    Co-Authors: Daniel Gackowski, Marta Starczak, Martyna Modrzejewska, Ewelina Zarakowska, Ryszard Olinski
    Abstract:

    Background Replication-independent active/enzymatic demethylation may be an important process in the functioning of somatic cells. The most plausible mechanisms of active 5-methylcytosine demethylation, leading to activation of previously silenced genes, involve ten-eleven translocation (TET) proteins that participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine which can be further oxidized to 5-formylcytosine and 5-carboxylcytosine. Recently, 5-hydroxymethylcytosine was demonstrated to be a relatively stable modification, and the previously observed substantial differences in the level of this modification in various murine tissues were shown to depend mostly on cell proliferation rate. Some experimental evidence supports the hypothesis that 5Hydroxymethyluracil may be also generated by TET enzymes and has epigenetic functions. Results Using an isotope-dilution automated online two-dimensional ultra-performance liquid chrochromatography with tandem mass spectrometry, we have analyzed, for the first time, all the products of active DNA demethylation pathway: 5-methyl-2′-deoxycytidine, 5-hydroxymethyl-2′-deoxycytidine, 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine, as well as 5-hydroxymethyl-2′-deoxyuridine, in DNA isolated from various rat and porcine tissues. A strong significant inverse linear correlation was found between the proliferation rate of cells and the global level of 5-hydroxymethyl-2′-deoxycytidine in both porcine (R2 = 0.88) and rat tissues (R2 = 0.83); no such relationship was observed for 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine. Moreover, a substrate-product correlation was demonstrated for the two consecutive steps of iterative oxidation pathway: between 5-hydroxymethyl-2′-deoxycytidine and its product 5-formyl-2′-deoxycytidine, as well as between 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine (R2 = 0.60 and R2 = 0.71, respectively). Conclusions Good correlations within the substrate-product sets of iterative oxidation pathway may suggest that a part of 5-formyl-2′-deoxycytidine and/or 5-carboxyl-2′-deoxycytidine can be directly linked to a small portion of 5-hydroxymethyl-2′-deoxycytidine which defines the active demethylation process.

Daniel Gackowski – One of the best experts on this subject based on the ideXlab platform.

  • vitamin c enhances substantially formation of 5 Hydroxymethyluracil in cellular dna
    Free Radical Biology and Medicine, 2016
    Co-Authors: Martyna Modrzejewska, Daniel Gackowski, Marta Starczak, Maciej Gawronski, Magdalena Skonieczna, Ewelina Zarakowska, Marek Foksinski, Joanna Rzeszowskawolny, Ryszard Olinski
    Abstract:

    The most plausible mechanism behind active demethylation of 5-methylcytosine involves TET proteins which participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine; the latter is further oxidized to 5-formylcytosine and 5-carboxycytosine. 5Hydroxymethyluracil can be also generated from thymine in a TET-catalyzed process. Ascorbate was previously demonstrated to enhance generation of 5-hydroxymethylcytosine in cultured cells. The aim of this study was to determine the levels of the abovementioned TET-mediated oxidation products of 5-methylcytosine and thymine after addition of ascorbate, using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Intracellular concentration of ascorbate was determined by means of ultra-performance liquid chromatography with UV detection. Irrespective of its concentration in culture medium (10-100µM) and inside the cell, ascorbate stimulated a moderate (2- to 3-fold) albeit persistent (up to 96-h) increase in the level of 5-hydroxymethylcytosine. However, exposure of cells to higher concentrations of ascorbate (100µM or 1mM) stimulated a substantial increase in 5-formylcytosine and 5-carboxycytosine levels. Moreover, for the first time we demonstrated a spectacular (up to 18.5-fold) increase in 5Hydroxymethyluracil content what, in turn, suggests that TET enzymes contributed to the presence of the modification in cellular DNA. These findings suggest that physiological concentrations of ascorbate in human serum (10-100µM) are sufficient to maintain a stable level of 5-hydroxymethylcytosine in cellular DNA. However, markedly higher concentrations of ascorbate (ca. 100µM in the cell milieu or ca. 1mM inside the cell) were needed to obtain a sustained increase in 5-formylcytosine, 5-carboxycytosine and 5Hydroxymethyluracil levels. Such feedback to elevated concentrations of ascorbate may reflect adaptation of the cell to environmental conditions.

  • enigmatic 5 Hydroxymethyluracil oxidatively modified base epigenetic mark or both
    Mutation Research-reviews in Mutation Research, 2016
    Co-Authors: Ryszard Olinski, Marta Starczak, Daniel Gackowski
    Abstract:

    The aim of this review is to describe the reactions which lead to generation of 5Hydroxymethyluracil, as well as the repair processes involved in its removal from DNA, and its level in various cells and urine. 5Hydroxymethyluracil may be formed during the course of the two processes: oxidation/hydroxylation of thymine with resultant formation of 5Hydroxymethyluracil paired with adenine (produced by reactive oxygen species), and reacting of reactive oxygen species with 5-methylcytosine forming 5-hydroxymethylcytosine, followed by its deamination to 5Hydroxymethyluracil mispaired with guanine. However, other, perhaps enzymatic, mechanism(s) may be involved in formation of 5Hydroxymethyluracil mispaired with guanine. Indeed, this mispair may be also formed as a result of deamination of 5-hydroxymethylcytosine, recently described “sixth” DNA base. It was demonstrated that 5Hydroxymethyluracil paired with adenine can be also generated by TET enzymes from thymine during mouse embryonic cell differentiation. Therefore, it is possible that 5Hydroxymethyluracil is epigenetic mark. The level of 5Hydroxymethyluracil in various somatic tissues is relatively stable and resembles that observed in lymphocytes, about 0.5/10(6) dN in human colon, colorectal cancer as well as various rat and porcine tissues. Experimental evidence suggests that SMUG1 and TDG are main enzymes involved in removal of 5Hydroxymethyluracil from DNA. 5Hydroxymethyluracil, in form of 5-hydroxymethyluridine, was also detected in rRNA, and together with SMUG1 may play a role in rRNA quality control. To summarize, 5Hydroxymethyluracil is with no doubt a product of both enzymatic and reactive oxygen species-induced reaction. This modification may probably serve as an epigenetic mark, providing additional layer of information encoded within the genome. However, the pool of 5Hydroxymethyluracil generated as a result of oxidative stress is also likely to disturb physiological epigenetic processes, and as such may be defined as a lesion. Altogether this suggests that 5Hydroxymethyluracil may be either a regulatory or erroneous compound.

  • tissue specific differences in dna modifications 5 hydroxymethylcytosine 5 formylcytosine 5 carboxylcytosine and 5 Hydroxymethyluracil and their interrelationships
    PLOS ONE, 2015
    Co-Authors: Daniel Gackowski, Marta Starczak, Martyna Modrzejewska, Ewelina Zarakowska, Ryszard Olinski
    Abstract:

    Background Replication-independent active/enzymatic demethylation may be an important process in the functioning of somatic cells. The most plausible mechanisms of active 5-methylcytosine demethylation, leading to activation of previously silenced genes, involve ten-eleven translocation (TET) proteins that participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine which can be further oxidized to 5-formylcytosine and 5-carboxylcytosine. Recently, 5-hydroxymethylcytosine was demonstrated to be a relatively stable modification, and the previously observed substantial differences in the level of this modification in various murine tissues were shown to depend mostly on cell proliferation rate. Some experimental evidence supports the hypothesis that 5Hydroxymethyluracil may be also generated by TET enzymes and has epigenetic functions. Results Using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with tandem mass spectrometry, we have analyzed, for the first time, all the products of active DNA demethylation pathway: 5-methyl-2′-deoxycytidine, 5-hydroxymethyl-2′-deoxycytidine, 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine, as well as 5-hydroxymethyl-2′-deoxyuridine, in DNA isolated from various rat and porcine tissues. A strong significant inverse linear correlation was found between the proliferation rate of cells and the global level of 5-hydroxymethyl-2′-deoxycytidine in both porcine (R2 = 0.88) and rat tissues (R2 = 0.83); no such relationship was observed for 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine. Moreover, a substrate-product correlation was demonstrated for the two consecutive steps of iterative oxidation pathway: between 5-hydroxymethyl-2′-deoxycytidine and its product 5-formyl-2′-deoxycytidine, as well as between 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine (R2 = 0.60 and R2 = 0.71, respectively). Conclusions Good correlations within the substrate-product sets of iterative oxidation pathway may suggest that a part of 5-formyl-2′-deoxycytidine and/or 5-carboxyl-2′-deoxycytidine can be directly linked to a small portion of 5-hydroxymethyl-2′-deoxycytidine which defines the active demethylation process.

George W Teebor – One of the best experts on this subject based on the ideXlab platform.

Marta Starczak – One of the best experts on this subject based on the ideXlab platform.

  • vitamin c enhances substantially formation of 5 Hydroxymethyluracil in cellular dna
    Free Radical Biology and Medicine, 2016
    Co-Authors: Martyna Modrzejewska, Daniel Gackowski, Marta Starczak, Maciej Gawronski, Magdalena Skonieczna, Ewelina Zarakowska, Marek Foksinski, Joanna Rzeszowskawolny, Ryszard Olinski
    Abstract:

    The most plausible mechanism behind active demethylation of 5-methylcytosine involves TET proteins which participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine; the latter is further oxidized to 5-formylcytosine and 5-carboxycytosine. 5Hydroxymethyluracil can be also generated from thymine in a TET-catalyzed process. Ascorbate was previously demonstrated to enhance generation of 5-hydroxymethylcytosine in cultured cells. The aim of this study was to determine the levels of the abovementioned TET-mediated oxidation products of 5-methylcytosine and thymine after addition of ascorbate, using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Intracellular concentration of ascorbate was determined by means of ultra-performance liquid chromatography with UV detection. Irrespective of its concentration in culture medium (10-100µM) and inside the cell, ascorbate stimulated a moderate (2- to 3-fold) albeit persistent (up to 96-h) increase in the level of 5-hydroxymethylcytosine. However, exposure of cells to higher concentrations of ascorbate (100µM or 1mM) stimulated a substantial increase in 5-formylcytosine and 5-carboxycytosine levels. Moreover, for the first time we demonstrated a spectacular (up to 18.5-fold) increase in 5Hydroxymethyluracil content what, in turn, suggests that TET enzymes contributed to the presence of the modification in cellular DNA. These findings suggest that physiological concentrations of ascorbate in human serum (10-100µM) are sufficient to maintain a stable level of 5-hydroxymethylcytosine in cellular DNA. However, markedly higher concentrations of ascorbate (ca. 100µM in the cell milieu or ca. 1mM inside the cell) were needed to obtain a sustained increase in 5-formylcytosine, 5-carboxycytosine and 5Hydroxymethyluracil levels. Such feedback to elevated concentrations of ascorbate may reflect adaptation of the cell to environmental conditions.

  • enigmatic 5 Hydroxymethyluracil oxidatively modified base epigenetic mark or both
    Mutation Research-reviews in Mutation Research, 2016
    Co-Authors: Ryszard Olinski, Marta Starczak, Daniel Gackowski
    Abstract:

    The aim of this review is to describe the reactions which lead to generation of 5Hydroxymethyluracil, as well as the repair processes involved in its removal from DNA, and its level in various cells and urine. 5Hydroxymethyluracil may be formed during the course of the two processes: oxidation/hydroxylation of thymine with resultant formation of 5Hydroxymethyluracil paired with adenine (produced by reactive oxygen species), and reacting of reactive oxygen species with 5-methylcytosine forming 5-hydroxymethylcytosine, followed by its deamination to 5Hydroxymethyluracil mispaired with guanine. However, other, perhaps enzymatic, mechanism(s) may be involved in formation of 5Hydroxymethyluracil mispaired with guanine. Indeed, this mispair may be also formed as a result of deamination of 5-hydroxymethylcytosine, recently described “sixth” DNA base. It was demonstrated that 5Hydroxymethyluracil paired with adenine can be also generated by TET enzymes from thymine during mouse embryonic cell differentiation. Therefore, it is possible that 5Hydroxymethyluracil is epigenetic mark. The level of 5Hydroxymethyluracil in various somatic tissues is relatively stable and resembles that observed in lymphocytes, about 0.5/10(6) dN in human colon, colorectal cancer as well as various rat and porcine tissues. Experimental evidence suggests that SMUG1 and TDG are main enzymes involved in removal of 5Hydroxymethyluracil from DNA. 5Hydroxymethyluracil, in form of 5-hydroxymethyluridine, was also detected in rRNA, and together with SMUG1 may play a role in rRNA quality control. To summarize, 5Hydroxymethyluracil is with no doubt a product of both enzymatic and reactive oxygen species-induced reaction. This modification may probably serve as an epigenetic mark, providing additional layer of information encoded within the genome. However, the pool of 5Hydroxymethyluracil generated as a result of oxidative stress is also likely to disturb physiological epigenetic processes, and as such may be defined as a lesion. Altogether this suggests that 5Hydroxymethyluracil may be either a regulatory or erroneous compound.

  • tissue specific differences in dna modifications 5 hydroxymethylcytosine 5 formylcytosine 5 carboxylcytosine and 5 Hydroxymethyluracil and their interrelationships
    PLOS ONE, 2015
    Co-Authors: Daniel Gackowski, Marta Starczak, Martyna Modrzejewska, Ewelina Zarakowska, Ryszard Olinski
    Abstract:

    Background Replication-independent active/enzymatic demethylation may be an important process in the functioning of somatic cells. The most plausible mechanisms of active 5-methylcytosine demethylation, leading to activation of previously silenced genes, involve ten-eleven translocation (TET) proteins that participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine which can be further oxidized to 5-formylcytosine and 5-carboxylcytosine. Recently, 5-hydroxymethylcytosine was demonstrated to be a relatively stable modification, and the previously observed substantial differences in the level of this modification in various murine tissues were shown to depend mostly on cell proliferation rate. Some experimental evidence supports the hypothesis that 5Hydroxymethyluracil may be also generated by TET enzymes and has epigenetic functions. Results Using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with tandem mass spectrometry, we have analyzed, for the first time, all the products of active DNA demethylation pathway: 5-methyl-2′-deoxycytidine, 5-hydroxymethyl-2′-deoxycytidine, 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine, as well as 5-hydroxymethyl-2′-deoxyuridine, in DNA isolated from various rat and porcine tissues. A strong significant inverse linear correlation was found between the proliferation rate of cells and the global level of 5-hydroxymethyl-2′-deoxycytidine in both porcine (R2 = 0.88) and rat tissues (R2 = 0.83); no such relationship was observed for 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine. Moreover, a substrate-product correlation was demonstrated for the two consecutive steps of iterative oxidation pathway: between 5-hydroxymethyl-2′-deoxycytidine and its product 5-formyl-2′-deoxycytidine, as well as between 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine (R2 = 0.60 and R2 = 0.71, respectively). Conclusions Good correlations within the substrate-product sets of iterative oxidation pathway may suggest that a part of 5-formyl-2′-deoxycytidine and/or 5-carboxyl-2′-deoxycytidine can be directly linked to a small portion of 5-hydroxymethyl-2′-deoxycytidine which defines the active demethylation process.

Martyna Modrzejewska – One of the best experts on this subject based on the ideXlab platform.

  • vitamin c enhances substantially formation of 5 Hydroxymethyluracil in cellular dna
    Free Radical Biology and Medicine, 2016
    Co-Authors: Martyna Modrzejewska, Daniel Gackowski, Marta Starczak, Maciej Gawronski, Magdalena Skonieczna, Ewelina Zarakowska, Marek Foksinski, Joanna Rzeszowskawolny, Ryszard Olinski
    Abstract:

    The most plausible mechanism behind active demethylation of 5-methylcytosine involves TET proteins which participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine; the latter is further oxidized to 5-formylcytosine and 5-carboxycytosine. 5Hydroxymethyluracil can be also generated from thymine in a TET-catalyzed process. Ascorbate was previously demonstrated to enhance generation of 5-hydroxymethylcytosine in cultured cells. The aim of this study was to determine the levels of the abovementioned TET-mediated oxidation products of 5-methylcytosine and thymine after addition of ascorbate, using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Intracellular concentration of ascorbate was determined by means of ultra-performance liquid chromatography with UV detection. Irrespective of its concentration in culture medium (10-100µM) and inside the cell, ascorbate stimulated a moderate (2- to 3-fold) albeit persistent (up to 96-h) increase in the level of 5-hydroxymethylcytosine. However, exposure of cells to higher concentrations of ascorbate (100µM or 1mM) stimulated a substantial increase in 5-formylcytosine and 5-carboxycytosine levels. Moreover, for the first time we demonstrated a spectacular (up to 18.5-fold) increase in 5Hydroxymethyluracil content what, in turn, suggests that TET enzymes contributed to the presence of the modification in cellular DNA. These findings suggest that physiological concentrations of ascorbate in human serum (10-100µM) are sufficient to maintain a stable level of 5-hydroxymethylcytosine in cellular DNA. However, markedly higher concentrations of ascorbate (ca. 100µM in the cell milieu or ca. 1mM inside the cell) were needed to obtain a sustained increase in 5-formylcytosine, 5-carboxycytosine and 5Hydroxymethyluracil levels. Such feedback to elevated concentrations of ascorbate may reflect adaptation of the cell to environmental conditions.

  • tissue specific differences in dna modifications 5 hydroxymethylcytosine 5 formylcytosine 5 carboxylcytosine and 5 Hydroxymethyluracil and their interrelationships
    PLOS ONE, 2015
    Co-Authors: Daniel Gackowski, Marta Starczak, Martyna Modrzejewska, Ewelina Zarakowska, Ryszard Olinski
    Abstract:

    Background Replication-independent active/enzymatic demethylation may be an important process in the functioning of somatic cells. The most plausible mechanisms of active 5-methylcytosine demethylation, leading to activation of previously silenced genes, involve ten-eleven translocation (TET) proteins that participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine which can be further oxidized to 5-formylcytosine and 5-carboxylcytosine. Recently, 5-hydroxymethylcytosine was demonstrated to be a relatively stable modification, and the previously observed substantial differences in the level of this modification in various murine tissues were shown to depend mostly on cell proliferation rate. Some experimental evidence supports the hypothesis that 5Hydroxymethyluracil may be also generated by TET enzymes and has epigenetic functions. Results Using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with tandem mass spectrometry, we have analyzed, for the first time, all the products of active DNA demethylation pathway: 5-methyl-2′-deoxycytidine, 5-hydroxymethyl-2′-deoxycytidine, 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine, as well as 5-hydroxymethyl-2′-deoxyuridine, in DNA isolated from various rat and porcine tissues. A strong significant inverse linear correlation was found between the proliferation rate of cells and the global level of 5-hydroxymethyl-2′-deoxycytidine in both porcine (R2 = 0.88) and rat tissues (R2 = 0.83); no such relationship was observed for 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine. Moreover, a substrate-product correlation was demonstrated for the two consecutive steps of iterative oxidation pathway: between 5-hydroxymethyl-2′-deoxycytidine and its product 5-formyl-2′-deoxycytidine, as well as between 5-formyl-2′-deoxycytidine and 5-carboxyl-2′-deoxycytidine (R2 = 0.60 and R2 = 0.71, respectively). Conclusions Good correlations within the substrate-product sets of iterative oxidation pathway may suggest that a part of 5-formyl-2′-deoxycytidine and/or 5-carboxyl-2′-deoxycytidine can be directly linked to a small portion of 5-hydroxymethyl-2′-deoxycytidine which defines the active demethylation process.

  • urinary 5 Hydroxymethyluracil and 8 oxo 7 8 dihydroguanine as potential biomarkers in patients with colorectal cancer
    Biomarkers, 2015
    Co-Authors: Rafal Rozalski, Daniel Gackowski, Marta Starczak, Martyna Modrzejewska, Zbigniew Banaszkiewicz, Agnieszka Siomekgorecka, Ryszard Olinski
    Abstract:

    AbstractContext: Oxidative stress linked with chronic inflinflammation is associated with etiology of the colorectal cancer.Objectives: To assess the diagnostic utility of urinary excrexcretion of oxidatively modified DNA bases/nucleoside: 8-oxo-7,8-dihydroguanine (8-oxoGua), 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) and 5Hydroxymethyluracil (5-hmUra).Materials and methods: Seventy-two healthy controls, 15 patients with adenomas and 56 colorectal cancer patients were recruited.Results: The receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) for all markers tested separately was <0.7. The combination of these modifications showed better diagnostic power (AUC = 0.778 for 8-oxoGua + 8-oxodG)/5hmUra ratio).Conclusion: Urinary DNA modifications may reflect the oxidative stress/chronic inflinflammation in colorectal cancer but diagnostic performance for early-detection is moderate.