MicroRNAs in normal and cancer cells: a new class of gene expression regulators

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression at posttranscriptional level. They are involved in cellular development, differentiation, proliferation and apoptosis and play a significant role in cancer. This review describes miRNA biogenesis, their functions in normal cells, and alterations of miRNA sets in cancer and roles of antitumorigenic and oncogenic miRNAs in cancer development.Микро PHK(miRNAs) — это малое не кодирующие РНК, негативно регулирующие экспрессию генов на посттранскринц ионном уровне и принимаюшие участие в развитии, лифферешшровке. пролиферации и апоптозе клеток, а также выполняющие важную роль в опухолевом процессе. В обзоре обсужден биогенез miRNA, функции этих молекул в нормальных клетках, изменения набора miRNA в опухолевых клетках и роль противоопухолевых и онкогенных nnRNAs в опухолевой прогрессии. Ключевые сюва: микроРНК, рак. онкоген, опухолевый супрессор

Induction of oxidative stress in Rana ridibunda during recovery from winter hibernation

The effect of transfer from winter hibernation at 5°C to a warm temperature (20°C for 1 or 24 h) on oxidative stress and antioxidant defenses was assessed in the frog, Rana ridibunda. The temperature increase had little effect on the levels of thiobarbituric acid reactive substances but carbonylprotein levels (581, 740, 1270 and 614 pmol/mg protein in brain, liver, kidney and muscle, respectively, at 5°C) rose 3.2-fold in brain and 2.6-fold in liver after transfer to 20°C. The switch to 20°C also affected the activities of antioxidant enzymes: catalase in liver, kidney and muscle rose 33%, 55% and 126%, respectively, whereas superoxide dismutase increased 2.4-fold in liver and 2.5-fold in muscle. Glutathione reductase and glucose-6-phosphate dehydrogenase activities were also affected in some organs. The data show that recovery from winter hibernation in frogs causes increased oxidative stress and stimulates an elevation of organ antioxidant defenses

Activity and properties of phosphofructokinase in white muscle of horse mackerel Trachurus mediterraneus under swimming stimulation

The activity and properties of phosphofructokinase (PFK) in tissues of horse mackerel which was swimming at burst regimen for 5 min and at cruiser one for 60 min have been investigated. In white muscle the PFK activity increased 1,6-fold after burst swimming and Hill's coefficient rose as well and decreased 3-fold after cruiser one. Swimming did not change the half-maximal saturation constant for both substrates and inhibition constants for ATP and citrate. In the preparations from white muscle of fish which were stimulated by burst swimming the PFK activity at physiological pH values (6,0-7,0) was higher comparing with one from the control group and after cruiser swimming. Incubation of preparations at 45 °C decreased the activity of PFK in control and cruiser swimming groups (to 61-67% of initial level) and increased it after burst swimming (1,3-fold). The mechanisms involving in stable modification of PFK under different swimming regimens are discussed

Influence of exercise on the activity and the distribution between free and bound forms of glycolytic and associated enzymes in tissues of horse mackerel

The effects of short-term burst (5 min at 1.8 m/s) swimming and long-term cruiser (60 min at 1.2 m/s) swimming on maximal enzyme activities and enzyme distribution between free and bound states were assessed for nine glycolytic and associated enzymes in tissues of horse mackerel, Trachurus mediterraneus ponticus. The effects of exercise were greatest in white muscle. The activities of phosphofructokinase (PFK), pyruvate kinase (PK), fructose-1,6-bisphosphatase (FBPase), and phosphoglucomutase (PGM) all decreased to 47, 37, 37 and 67%, respectively, during 60-min exercise and all enzymes except phosphoglucoisomerase (PGI) and PGM showed a change in the extent of binding to subcellular particulate fractions during exercise. In red muscle, exercise affected the activities of PGI, FBPase, PFK, and lactate dehydrogenase (LDH) and altered percent binding of only PK and LDH. In liver, exercise increased the PK activity 2.3-fold and reduced PGI 1.7-fold only after 5 min of exercise but altered the percent binding of seven enzymes. Fewer effects were seen in brain, with changes in the activities of aldolase and PGM and in percent binding of hexokinase, PFK and PK. Changes in enzyme activities and in binding interactions with subcellular particulate matter appear to support the altered demands of tissue energy metabolism during exercise

Oxidative stress and antioxidant defense responses by goldfish tissues to acute change of temperature from 3 to 23 °C

The effects of a rapid transfer from a low (3 °C) to a warm (23 °C) temperature on oxidative stress markers and antioxidant defenses were studied in the brain, liver and kidney of the goldfish, Carassius auratus. Cold-acclimated fish were acutely moved to 23 °C and sampled after 1, 6, 12, 24, 48 or 120 h of warm temperature exposure. Lipid peroxide levels increased quickly during the first few hours at 23 °C, but thiobarbituric acid-reactive substances changed little. Protein carbonyl content was reduced by 20-40% in the liver over the entire experimental course, but increased transiently in the kidney. The content of high-molecular mass thiols decreased by two-thirds in the brain and was affected slightly i

Adaptive response of antioxidant enzymes to catalase inhibition by aminotriazole in goldfish liver and kidney

This study was undertaken to clarify the physiological role of catalase in the maintenance of pro/antioxidant balance in goldfish tissues by inhibiting the enzyme in vivo with 3-amino 1,2,4-triazole. Intraperitoneal injection of aminotriazole (0.5 mg/g wet mass) caused a decrease in liver catalase activity by 83% after 24 h that was sustained after 168 h post-injection. In kidney catalase activity was reduced by ∼50% and 70% at the two time points, respectively. Levels of protein carbonyls were unchanged in liver but rose by 2-fold in kidney after 168 h. Levels of thiobarbituric acid-reactive substances were elevated in both tissues after 24 h but were reversed by 168 h. Glutathione peroxidase and glutathione-S-transferase activities increased in kidney after aminotriazole treatment whereas activities of glutathione peroxidase and glutathione reductase in liver decreased after 24 h but rebounded by 168 h. Liver glucose-6-phosphate dehydrogenase activity was reduced at both time points. Activities of these three enzymes in liver correlated inversely with the levels of lipid damage products (R2 = 0.65-0.81) suggesting that they may have been oxidatively inactivated. Glutathione-S-transferase activity also correlated inversely with catalase (R2 = 0.86). Hence, the response to catalase depletion

Influence of exercise on the activity and the distribution between free and bound forms of glycolytic and associated enzymes in tissues of horse mackerel

The effects of short-term burst (5 min at 1.8 m/s) swimming and long-term cruiser (60 min at 1.2 m/s) swimming on maximal enzyme activities and enzyme distribution between free and bound states were assessed for nine glycolylic and associated enzymes in tissues of horse mackerel, Trachurus mediterraneus ponticus. The effects of exercise were greatest in white muscle. The activities of phosphofructokinase (PFK), pyruvate kinase (PK), fructose-1,6-bisphosphatase (FBPase), and phosphoglucomutase (PGM) all decreased to 47, 37, 37 and 67%, respectively, during 60-min exercise and all enzymes except phosphoglucoisomerase (PGI) and PGM showed a change in the extent of binding to subcellular particulate fractions during exercise. In red muscle, exercise affected the activities of PGI, FBPase, PFK, and lactate dehydrogenase (LDH) and altered percent binding of only PK and LDH. In liver, exercise increased the PK activity 2.3-fold and reduced PGI 1.7-fold only after 5 min of exercise but altered the percent binding of seven enzymes. Fewer effects were seen in brain, with changes in the activities of aldolase and

Catalase inhibition by amino triazole induces oxidative stress in goldfish brain

The effects of in vivo inhibition of catalase by 3-amino 1,2,4-triazole (AMT) on the levels of damage products resulting from reactive oxygen species attack on proteins and lipids as well as on the activities of five antioxidant and associated enzymes were studied in the brain of goldfish, Carassius auratus. Intraperitoneal injection of AMT at a concentration of 0.1 mg/g wet weight caused a gradual decrease in brain catalase activity over 72 h, whereas higher AMT concentrations (0.5 or 1.0 mg/g) reduced catalase activity by about two-thirds within 5-10 h. AMT effects on antioxidant enzyme activities and oxidative stress markers were studied in detail using fish treated with 0.5 mg/g AMT for 24 or 168 h. The levels of thiobarbituric acid-reactive substances (a lipid damage product) increased 6.5-fold by 24 h after AMT injection but fell again after 168 h. The content of carbonylproteins (CP) also rose within 24 h (by ∼2-fold) and remained 1.5-fold higher compared with respective sham-injected fish after 168 h. CP levels correlated inversely with catalase activity (R2 = 0.83) suggesting that catalase may protect proteins in vivo against oxidative modification. The activities of both glutathione peroxidase and glutathione-S-transferase increased by ∼50% and 80%, respectively, in brain of AMT-treated fish and this might represent a compensatory response to lowered catalase activity. Possible functions of catalase in the maintenance of prooxidant/antioxidant balance in goldfish brain are discussed

Hypoxia and recovery perturb free radical processes and antioxidant potential in common carp (Cyprinus carpio) tissues

The effects of hypoxia exposure and subsequent normoxic recovery on the levels of lipid peroxides (LOOH), thiobarbituric acid reactive substances (TBARS), carbonylproteins, total glutathione levels, and the activities of six antioxidant enzymes were measured in brain, liver, kidney and skeletal muscle of the common carp Cyprinus carpio. Hypoxia exposure (25% of normal oxygen level) for 5 h generally decreased the levels of oxidative damage pr