- Email: [email protected]
The comparison of vitamin E and vitamin C levels in type 2 diabetic patients under monotherapy
S54
A. Stepanova et al. / Free Radical Biology and Medicine 120 (2018) S45–S166
mitochondria. While it is now clear that recovery respiration is essential for tumour formation, its functional link to the process is unclear. It includes gradual increase in mtDNA level of homoplasmic host polymorphism, followed by binding of mtDNA-processing enzymes to its regulatory domain, replication and transcription of mtDNA, increased expression of components of respiratory complexes, resulting in full restoration of respiration. We found that pyrimidine biosynthesis, supported by the respiration-linked enzyme dihydroorotate dehydrogenase (DHODH), is critically required to overcome cell cycle arrest. We further confirmed that efficient de novo pyrimidine synthesis, necessary for tumour cell proliferation, is the key event for triggering tumour growth. Moreover, respiration recovery, which is necessary for tumour formation, is associated with efficient de novo pyrimidine synthesis. In conclusion, we propose that DHODH is a critical link between de novo pyrimidine synthesis and respiration, and that it is a promising target for broad-spectrum cancer therapy.
E-mail address: l.dong@griffith.edu.au http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.177
lead to the appearance of biochemical markers of cell death compatible with MPT-driven necrosis
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.178
P-32
The tumor environment stabilizes c-Myc oncoprotein through its sustained phosphorylation at serine 62, which promotes its oncogenic activity Deepika Raman 1, Shazib Pervaiz 1,2,3 1
National University of Singapore, Singapore National University Cancer Institute, Singapore 3 NUS Graduate School for Integrative Sciences and Engineering, Singapore 2
P-31
Impact of peroxynitrite-mediated nitrosative stress on human sperm cells Pamela Uribe 1,2, Juana V. Villegas 2,3, María E. Cabrillana 4,5, Rodrigo Boguen 3, Raúl Sánchez 1,6, Miguel W. Fornés 4,5, Vladimir Isachenko 7, Evgenia Isachenko 7 1
Center of Excellence in Translational Medicine, Universidad de La Frontera, Temuco, Chile 2 Department of Internal Medicine, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile 3 Center of Reproductive Biotechnology - Scientific and Technological Bioresource Nucleus (CEBIOR – BIOREN), Universidad de La Frontera, Temuco, Chile 4 Laboratory of Andrology Research of Mendoza (LIAM) Institute of Histology and Embriology of Mendoza (IHEM) Histology and Embryology Area, Department of Morphology and Physiology, School of Medicine, National University of Cuyo & CCT-Mendoza, CONICET, Mendoza, Argentina 5 Research Institute (CIUDA), Medicine Faculty, Universidad del Aconcagua. Mendoza, Argentina 6 Department of Preclinical Sciences, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile 7 Research Group for Reproductive Medicine, Cologne University, Cologne, Germany
We have previously demonstrated that redox homeostasis is governed by two key ROS – superoxide anion (O2-) and hydrogen peroxide (H2O2). Tilting the balance to O2- contributes to engaging cancers onto a prosurvival trajectory. Here, we present a singular event wherein redox modulation of c-Myc attributes cancer cells with survival advantages and elevates their chemoresistance potential. Phosphorylation of c-Myc correlates with its stabilization in cancers. While S62 phosphorylation increases c-Myc stability, T58 phosphorylation destabilizes it. Of particular interest is phosphatase PP2A, as we have shown that it is amenable to redox insults. We have now elucidated that B56α regulatory subunit of PP2A is amenable to redox modification preventing interaction of c-Myc bound B56α with PP2A-AC core enzyme. As assembly of PP2A holoenzyme is disrupted, c-Myc remains phosphorylated at S62. Hyperphosphorylated c-Myc cannot be recognized and engaged by the proteasome leading to increased protein stability and a moderate rise in activation of c-Myc targets. Thus, we have established a novel mechanism wherein the balance between O2-:H2O2 ratio stimulates a pro-survival milieu and reinforces chemoresistance through redox modification of PP2A-B56α, consequentially resulting in stabilization of c-Myc.
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.179
P-33 Nitrosative stress is caused by high levels of reactive nitrogen species (RNS) and among the most toxic RNS is peroxynitrite. In infertile men there is an association between high levels of peroxynitrite and decreased sperm quality; however, less is known about the specific cellular impairment caused by peroxynitrite in sperm cells. The aim here was to characterize the in vitro effect of peroxynitrite on human sperm. For this, spermatozoa were exposed to 3-morpholinosydnonimine, a compound that generates peroxynitrite, and several parameters of sperm quality and biochemical markers of cell death were assessed. Untreated sperm were included as controls. At early incubation times peroxynitrite exposure caused a decrease in mitochondrial membrane potential, ATP level and motility while thiol oxidation and tyrosine nitration increased. At prolonged incubation time viability decreased and DNA oxidation, DNA fragmentation and ultrastructural damage increased. Mitochondrial permeability transition (MPT) was induced while caspase activation and phosphatidylserine externalization were not evidenced. These results indicate that peroxynitrite exposure impairs sperm function and ultrastructure and
The comparison of vitamin E and vitamin C levels in type 2 diabetic patients under monotherapy Ayse C. Hamamcioglu 1, Zehra Safi-Oz 2, Yasin Hazer 3, Taner Bayraktaroglu 4 1
Biochemistry Department, Faculty of Pharmacy, Bulent Ecevit University, Zonguldak, Turkey 2 Medical Biology Department, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey 3 Pharmaceutical Botany Department, Faculty of Pharmacy, Bulent Ecevit University, Zonguldak, Turkey 4 Endocrinology and Metabolism Department, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey
A. Stepanova et al. / Free Radical Biology and Medicine 120 (2018) S45–S166
Background: In Type 2 Diabetes Mellitus (T2DM) high blood glucose levels increases oxidative stress. Metformin is a first-choice antidiabetic drug for T2DM patients to lower blood glucose levels, oxidative stress and provide better lipid profiles. Objectives: This study was planned to detect antioxidant vitamin (E and C) levels in T2DM patients at the time of diagnose (t ¼0) and after 6 months of monotherapy (t¼ 180). Methods: A total of 17 patients were recruited. Blood samples (10 ml) were taken when patients were first diagnosed with T2DM and after six months of Metformin usage. We also had an age and sex matched control group. Results: Vitamin C levels of T2DM patients t ¼0 was significantly lower than the healthy controls (p ¼ 0.000). At t ¼ 180, Vitamin C levels of patients almost reached the Vitamin C levels of controls and this elevation was found to be significant between t¼ 180 and t¼ 0 (p ¼ 0.001). On the other hand, Vitamin E levels of healthy controls and T2DM patients t ¼ 0 were not significantly different. At t ¼ 180, Vitamin E levels of T2DM patients were detected as significantly lower than healthy controls (p ¼0.267). Conclusion: Our data suggests that there is an inverse correlation between Vitamin C and Vitamin E levels of T2DM patients under monotherapy for 6 months period
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.180
P-34
S55
P-35
Free-radical fragmentation reactions of biomolecules involving C-C, C-O and C-N bond cleavage O.I. Shadyro Belarusian State University, Minsk, Belarus
Among a wide variety of homolytic transformations taking place in biomolecules, the oxidation processes occurring in the cell membrane lipids have been the most thoroughly studied ones. For such processes to be realized, the presence of oxygen is necessary. At low O2 concentrations the probability of oxidation processes decreases, enabling other types of free-radical reactions to occur in biomolecules. In our studies, a concept is being developed focusing on the important contribution of free-radical fragmentation reactions involving C-C, C-O and C-N bond rupture in organic molecules to the biosystem damage. Such processes can take place without participation of oxygen and may lead not only to destruction and modification of biologically relevant compounds but to accumulation of physiologically active products as well. The reactions resulting in the C-C, C-O or C-N bond ruptures occurring in an organism are known to be catalyzed by lyases. Many of these reactions proceed according to a free-radical mechanism. The report will be focused on discussion of the above-named fragmentation reactions of biomolecules and the possible consequences of their realization in an organism.
E-mail address: [email protected]
Kinetics and biological consequences of quinone-induced protein adduction
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.182
Nan Shu, Lasse G. Lorentzen, Michael J. Davies Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
Quinones are a major class of toxicological compounds, that can both generate radicals, and act as Michael acceptors with nucleophiles including Cys residues on proteins. This study aimed to quantitatively assess quinone-protein reactions and examine the relationship between quinone adduction and protein dysfunction. A range of quinones were incubated with glyceraldehyde-3-phosphate dehydrogenase (GAPDH), creatine kinase (CK), papain, bovine serum albumin (BSA), and human serum albumin (HSA), with both the kinetics of adduction and effects on protein structure and activity determined. Adduction rate constants at Cys residues, which were dependent on the quinone and protein structures, and thiol pKa, were in the range 103 -105 M-1s-1. p-Benzoquinone (BQ) induced dimerization of GAPDH and CK (but not BSA, HSA, or papain) in a dose- and time-dependent manner, as well as a loss of enzyme activity. Glutathione (GSH) reacts competitively with BQ, and can thereby reverse the activity loss and dimerization of GAPDH and CK. Mass spectrometry, after digestion to peptide, showed that BQ preferentially forms adducts with GAPDH at Cys149 and Cys244. These data suggest that quinones can induce toxicity by rapidly and selectively forming adducts with Cys residues in proteins.
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.181
P-36
Investigation of the effect of biologically active supplements on oxidative stability of flaxseed oil Irina Edimecheva, Anna Sosnovskaya, Oleg Shadyro Belarusian State University, Research Institute for Physical Chemical Problems of the Belarusian State University, Minsk, Belarus
The influence of added vitamins and other biologically active substances (BAS) (α-tocopherol, α-tocopherol acetate, cholecalciferol, β-carotene, lutein, zeaxanthin, coenzyme Q10, selenomethionine) on resistance of flaxseed oil to oxidation, was investigated. For this purpose, kinetic data were obtained on accumulation of primary and secondary oxidation products, free fatty acids in flaxseed oil, as well as the consumption of BAS during the storage of flaxseed oil enriched with supplements. It was shown that the supplements used to enrich flaxseed oil could exhibit both antioxidant and pro-oxidant properties depending on their chemical structure and concentration. The fat-soluble esters of ascorbic acid and their compositions with natural antioxidants based on legumes have shown to be effective and safe stabilizers of BAS enriched flaxseed oil, which enable to substantially inhibit the oxidation and oxidative destruction of flaxseed oil lipids, to reduce the losses of BAS, and, therefore, to extend the storage period of the oil. Basing on the investigation results, the formulas of new, oxidation-resistant functional food products based on flaxseed oil have been developed, and their production has been organized.
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.183
A. Stepanova et al. / Free Radical Biology and Medicine 120 (2018) S45–S166
mitochondria. While it is now clear that recovery respiration is essential for tumour formation, its functional link to the process is unclear. It includes gradual increase in mtDNA level of homoplasmic host polymorphism, followed by binding of mtDNA-processing enzymes to its regulatory domain, replication and transcription of mtDNA, increased expression of components of respiratory complexes, resulting in full restoration of respiration. We found that pyrimidine biosynthesis, supported by the respiration-linked enzyme dihydroorotate dehydrogenase (DHODH), is critically required to overcome cell cycle arrest. We further confirmed that efficient de novo pyrimidine synthesis, necessary for tumour cell proliferation, is the key event for triggering tumour growth. Moreover, respiration recovery, which is necessary for tumour formation, is associated with efficient de novo pyrimidine synthesis. In conclusion, we propose that DHODH is a critical link between de novo pyrimidine synthesis and respiration, and that it is a promising target for broad-spectrum cancer therapy.
E-mail address: l.dong@griffith.edu.au http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.177
lead to the appearance of biochemical markers of cell death compatible with MPT-driven necrosis
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.178
P-32
The tumor environment stabilizes c-Myc oncoprotein through its sustained phosphorylation at serine 62, which promotes its oncogenic activity Deepika Raman 1, Shazib Pervaiz 1,2,3 1
National University of Singapore, Singapore National University Cancer Institute, Singapore 3 NUS Graduate School for Integrative Sciences and Engineering, Singapore 2
P-31
Impact of peroxynitrite-mediated nitrosative stress on human sperm cells Pamela Uribe 1,2, Juana V. Villegas 2,3, María E. Cabrillana 4,5, Rodrigo Boguen 3, Raúl Sánchez 1,6, Miguel W. Fornés 4,5, Vladimir Isachenko 7, Evgenia Isachenko 7 1
Center of Excellence in Translational Medicine, Universidad de La Frontera, Temuco, Chile 2 Department of Internal Medicine, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile 3 Center of Reproductive Biotechnology - Scientific and Technological Bioresource Nucleus (CEBIOR – BIOREN), Universidad de La Frontera, Temuco, Chile 4 Laboratory of Andrology Research of Mendoza (LIAM) Institute of Histology and Embriology of Mendoza (IHEM) Histology and Embryology Area, Department of Morphology and Physiology, School of Medicine, National University of Cuyo & CCT-Mendoza, CONICET, Mendoza, Argentina 5 Research Institute (CIUDA), Medicine Faculty, Universidad del Aconcagua. Mendoza, Argentina 6 Department of Preclinical Sciences, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile 7 Research Group for Reproductive Medicine, Cologne University, Cologne, Germany
We have previously demonstrated that redox homeostasis is governed by two key ROS – superoxide anion (O2-) and hydrogen peroxide (H2O2). Tilting the balance to O2- contributes to engaging cancers onto a prosurvival trajectory. Here, we present a singular event wherein redox modulation of c-Myc attributes cancer cells with survival advantages and elevates their chemoresistance potential. Phosphorylation of c-Myc correlates with its stabilization in cancers. While S62 phosphorylation increases c-Myc stability, T58 phosphorylation destabilizes it. Of particular interest is phosphatase PP2A, as we have shown that it is amenable to redox insults. We have now elucidated that B56α regulatory subunit of PP2A is amenable to redox modification preventing interaction of c-Myc bound B56α with PP2A-AC core enzyme. As assembly of PP2A holoenzyme is disrupted, c-Myc remains phosphorylated at S62. Hyperphosphorylated c-Myc cannot be recognized and engaged by the proteasome leading to increased protein stability and a moderate rise in activation of c-Myc targets. Thus, we have established a novel mechanism wherein the balance between O2-:H2O2 ratio stimulates a pro-survival milieu and reinforces chemoresistance through redox modification of PP2A-B56α, consequentially resulting in stabilization of c-Myc.
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.179
P-33 Nitrosative stress is caused by high levels of reactive nitrogen species (RNS) and among the most toxic RNS is peroxynitrite. In infertile men there is an association between high levels of peroxynitrite and decreased sperm quality; however, less is known about the specific cellular impairment caused by peroxynitrite in sperm cells. The aim here was to characterize the in vitro effect of peroxynitrite on human sperm. For this, spermatozoa were exposed to 3-morpholinosydnonimine, a compound that generates peroxynitrite, and several parameters of sperm quality and biochemical markers of cell death were assessed. Untreated sperm were included as controls. At early incubation times peroxynitrite exposure caused a decrease in mitochondrial membrane potential, ATP level and motility while thiol oxidation and tyrosine nitration increased. At prolonged incubation time viability decreased and DNA oxidation, DNA fragmentation and ultrastructural damage increased. Mitochondrial permeability transition (MPT) was induced while caspase activation and phosphatidylserine externalization were not evidenced. These results indicate that peroxynitrite exposure impairs sperm function and ultrastructure and
The comparison of vitamin E and vitamin C levels in type 2 diabetic patients under monotherapy Ayse C. Hamamcioglu 1, Zehra Safi-Oz 2, Yasin Hazer 3, Taner Bayraktaroglu 4 1
Biochemistry Department, Faculty of Pharmacy, Bulent Ecevit University, Zonguldak, Turkey 2 Medical Biology Department, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey 3 Pharmaceutical Botany Department, Faculty of Pharmacy, Bulent Ecevit University, Zonguldak, Turkey 4 Endocrinology and Metabolism Department, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey
A. Stepanova et al. / Free Radical Biology and Medicine 120 (2018) S45–S166
Background: In Type 2 Diabetes Mellitus (T2DM) high blood glucose levels increases oxidative stress. Metformin is a first-choice antidiabetic drug for T2DM patients to lower blood glucose levels, oxidative stress and provide better lipid profiles. Objectives: This study was planned to detect antioxidant vitamin (E and C) levels in T2DM patients at the time of diagnose (t ¼0) and after 6 months of monotherapy (t¼ 180). Methods: A total of 17 patients were recruited. Blood samples (10 ml) were taken when patients were first diagnosed with T2DM and after six months of Metformin usage. We also had an age and sex matched control group. Results: Vitamin C levels of T2DM patients t ¼0 was significantly lower than the healthy controls (p ¼ 0.000). At t ¼ 180, Vitamin C levels of patients almost reached the Vitamin C levels of controls and this elevation was found to be significant between t¼ 180 and t¼ 0 (p ¼ 0.001). On the other hand, Vitamin E levels of healthy controls and T2DM patients t ¼ 0 were not significantly different. At t ¼ 180, Vitamin E levels of T2DM patients were detected as significantly lower than healthy controls (p ¼0.267). Conclusion: Our data suggests that there is an inverse correlation between Vitamin C and Vitamin E levels of T2DM patients under monotherapy for 6 months period
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.180
P-34
S55
P-35
Free-radical fragmentation reactions of biomolecules involving C-C, C-O and C-N bond cleavage O.I. Shadyro Belarusian State University, Minsk, Belarus
Among a wide variety of homolytic transformations taking place in biomolecules, the oxidation processes occurring in the cell membrane lipids have been the most thoroughly studied ones. For such processes to be realized, the presence of oxygen is necessary. At low O2 concentrations the probability of oxidation processes decreases, enabling other types of free-radical reactions to occur in biomolecules. In our studies, a concept is being developed focusing on the important contribution of free-radical fragmentation reactions involving C-C, C-O and C-N bond rupture in organic molecules to the biosystem damage. Such processes can take place without participation of oxygen and may lead not only to destruction and modification of biologically relevant compounds but to accumulation of physiologically active products as well. The reactions resulting in the C-C, C-O or C-N bond ruptures occurring in an organism are known to be catalyzed by lyases. Many of these reactions proceed according to a free-radical mechanism. The report will be focused on discussion of the above-named fragmentation reactions of biomolecules and the possible consequences of their realization in an organism.
E-mail address: [email protected]
Kinetics and biological consequences of quinone-induced protein adduction
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.182
Nan Shu, Lasse G. Lorentzen, Michael J. Davies Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
Quinones are a major class of toxicological compounds, that can both generate radicals, and act as Michael acceptors with nucleophiles including Cys residues on proteins. This study aimed to quantitatively assess quinone-protein reactions and examine the relationship between quinone adduction and protein dysfunction. A range of quinones were incubated with glyceraldehyde-3-phosphate dehydrogenase (GAPDH), creatine kinase (CK), papain, bovine serum albumin (BSA), and human serum albumin (HSA), with both the kinetics of adduction and effects on protein structure and activity determined. Adduction rate constants at Cys residues, which were dependent on the quinone and protein structures, and thiol pKa, were in the range 103 -105 M-1s-1. p-Benzoquinone (BQ) induced dimerization of GAPDH and CK (but not BSA, HSA, or papain) in a dose- and time-dependent manner, as well as a loss of enzyme activity. Glutathione (GSH) reacts competitively with BQ, and can thereby reverse the activity loss and dimerization of GAPDH and CK. Mass spectrometry, after digestion to peptide, showed that BQ preferentially forms adducts with GAPDH at Cys149 and Cys244. These data suggest that quinones can induce toxicity by rapidly and selectively forming adducts with Cys residues in proteins.
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.181
P-36
Investigation of the effect of biologically active supplements on oxidative stability of flaxseed oil Irina Edimecheva, Anna Sosnovskaya, Oleg Shadyro Belarusian State University, Research Institute for Physical Chemical Problems of the Belarusian State University, Minsk, Belarus
The influence of added vitamins and other biologically active substances (BAS) (α-tocopherol, α-tocopherol acetate, cholecalciferol, β-carotene, lutein, zeaxanthin, coenzyme Q10, selenomethionine) on resistance of flaxseed oil to oxidation, was investigated. For this purpose, kinetic data were obtained on accumulation of primary and secondary oxidation products, free fatty acids in flaxseed oil, as well as the consumption of BAS during the storage of flaxseed oil enriched with supplements. It was shown that the supplements used to enrich flaxseed oil could exhibit both antioxidant and pro-oxidant properties depending on their chemical structure and concentration. The fat-soluble esters of ascorbic acid and their compositions with natural antioxidants based on legumes have shown to be effective and safe stabilizers of BAS enriched flaxseed oil, which enable to substantially inhibit the oxidation and oxidative destruction of flaxseed oil lipids, to reduce the losses of BAS, and, therefore, to extend the storage period of the oil. Basing on the investigation results, the formulas of new, oxidation-resistant functional food products based on flaxseed oil have been developed, and their production has been organized.
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.183