[Effect of L-lysine alpha-oxidase from Trichoderma cf. aureoviride Rifai ВКМF-4268D on pheochromocytoma PC12 cell line].

L-Amino acid oxidases (L-ААО, EC 1.4.3.2) comprise a group of flavoproteins, catalyzing oxidative deamination of L-alpha amino acids to the corresponding alpha-keto acids, NH3 and Н2О2. In most cases these enzymes present homodimeric molecules with a molecular mass of 100-150 kDa, which were shown to possess antiviral, antifungal and antitumor activity. L-lysine alpha-oxidase (LO) holds an outstanding place among this group of enzymes and its biological role may differ significantly from the other L-AAO, because it cleaves an essential amino acid - L-lysine without significant action on the other amino acids. Although much research has examined LO effects in the organism, the molecular basis of these effects is yet to be identified. To fill this gap, the present work addressed one of hypothetical mechanisms of LO biological action using the enzyme from Trichoderma cf. aureoviride Rifai ВКМF-4268D and rat pheochromocytoma PC-12 as a model cell line. Using flow cytometry a dose-dependent cytotoxicity of LO was shown. The significant growth of intracellular reactive oxygen species levels, detected by 2,7-dichlorodihydrofluorescein assay, implies generation of peroxide as one of the molecular mechanisms of LO cytotoxic action, although this does not rule out other probable ways of LO action in the organizm.

Expression of peroxiredoxin 1, 2, 3, and 6 genes in cancer cells during drug resistance formation.

We studied the expression of peroxiredoxin genes (PRDX1, PRDX2, PRDX3, and PRDX6) in human erythroleukemia K652, human breast carcinoma MCF-7, and human ovarian carcinoma SKOV-3 cells during cisplatin resistance development. It was found that drug resistance formation was accompanied by a significant increase in the expression of PRDX1, PRDX2, PRDX3, PRDX6 genes in all cancer cell strains, which confirms the important contribution of redox-dependent mechanisms into the development of cisplatin resistance of cancer cells.

[Compensatory mechanisms to heal neuroplasticity impairment under Alzheiemer's disease neurodegeneration. I: The role of amyloid beta and its' precursor protein].

In-depth scholar literature analysis of Alzheimer's disease neurodegenerative features of amyloid beta protein neurochemistry modification and excessive phosphorylation of tau protein (and associated neuronal cytoskeleton rearrangements) are secondary phenomena. At early disease stage these neurobiochemical mechanisms are reversible and serve to heal an impairment of biophysical properties of neuronal membranes, neurotransmission, basic neuronal function and neuroplasticity, while preserving anatomical and functional brain fields. Abeta and tau could well serve to biochemically restore physico-chemical properties of neual membranes due to a role these proteins play in lipid metabolism. Under such scenario therapeutic block of aggregation and plaque formation of Abeta and inhibition of tau phosphorylation, as well as pharmaceutical modification of other secondary neurodegenerative features (such as a cascade of oxidative stress reactions) are unable to provide an effective cure of Alzheimer's disease and related pathologies of the Central and peripheral nervous systems, because they are not arraying primary pathagenetic cause. We review the role of Abeta in compensatory mechanisms of neuroplasticity restoration under normal physiological condition and Alzheimer's disease.

[L-amino acid oxidases: properties and molecular mechanisms of action].

During previous decade L-amino acid oxidases (LAAO) attracted the steady interest of researchers due to their poly functional effects on different biological systems. The review summarizes information concerning the sources, structure, phisico-chemical and catalytical properties of LAAO which exhibit antibacterial, antifungal, antiprotozoal, antiviral effects as well as the ambiguous action on platelet aggregation. Special attention is devoted to the elucidation of molecular mechanisms of LAAO action. It is proposed that the unique properties of LAAO) are based on their catalytic reaction, which causes the decrease of L-amino acid levels, including the essential amino acids and formation of hydrogen peroxide. The action of liberated H2O2 on cells involves the synthesis of oxygen reactive species and the development of necrotic and apoptotic pathways of cell death. The presence of carbohydrate moieties in LAAO molecules promotes their attachment to cell's surface and creation of high H2O2 local concentrations. The wide range of LAAO biological effects is undoubtedly connected with their important functional roles in the organism. In particular, it was shown that in the mice brain the LAAO-catalyzed reaction is the single pathway of L-lysine degradation, while in the mice milk LAAO carry out the antibacterial effect and in human leucocytes LAAO take part in fulfilling their defending role. Protector action may be also attributed to the oxidases from the other numerous sources: microscopic fungi, snake venoms and sea inhabitants.

[Investigation of antitumor substance from Trichoderma].

The effect of L-lysine-alpha-oxidase from Trichoderma harzianum Rifai on the functional activity of T-lymphocytes was investigated. It was shown that in a dose of 35 units/kg administered parentally the enzyme had no suppressive effect on the T-lymphocyte functional activity. An inhibitory effect of L-lysine-a-oxidase on some indices of the macrophages functional activity was observed. L-Lyzine-alpha-oxidase had a selective lymphotropic action and showed no mytostatic activity, which is in favour of the enzyme vs. other antitumor agents.

Matrix metalloproteinases 2, 7, and 9 in tumors and sera of patients with breast cancer.

Enzyme immunoassay showed that the content of matrix metalloproteinases (MMP) 2 and 7 in tumors was higher than in the adjacent histologically intact tissue in 91 and 76% patients with breast cancer, respectively, while MMP-9 levels in the tumor and intact tissue were virtually the same. Serum concentrations of MMP-2 and MMP-7 did not correlate with their levels in the tumors, were within the normal range, and virtually did not decrease after removal of the primary tumor. Serum levels of MMP-9 in patients were significantly lower than in the control and increased after surgery in 85% patients. No clear-cut relationship between the studied parameters and clinical morphological prognostic factors of breast cancer was detected.

[Participation of endotoxin from gram-negative bacteria in mechanisms of regulation of thyroid status].

Alteration of thyroid hormone blood levels in rats in different periods after exposure of high dose of lipopolysaccharide from E. coli were studied. Direct inhibition of thyroid function without hypothalamus-pituitary dysfunction is revealed. High dose by high doses of bacterial endotoxin leads to changes in rat thyroid status caused by both hypothalamus-pituitary and thyroid hypofunction.

[Current views on antioxidative activity of glutathione and glutathione-depending enzymes].

Reduced glutathione (GSH), gamma-glutamyl-L-cysteineglycine, is a tripeptide widespread in plants, animals, and man as a low-molecular weight SH-containing compound. This review presents results of published and original studies concerned with the synthesis and the role of glutathione and glutathione-dependent enzymes in antioxidative processes, such as maintenance and regulation of cell status, glutathionilation and deglutathionilation, redox-dependent signaling, and apoptosis.

[Regulation of thyroid and pituitary functions by lipopolysaccharide].

Activation of toll-like receptors-4 by bacterial lipopolysaccharide downregulates pituitary and thyroid function. Besides decrease of thyroid-stimulating hormone secretion lipopolysaccharide affects secretion in follicular thyroid cells directly. The endotoxin partially activates and inhibits different phases of follicular thyrocytes' secretion. Lipopolysaccharide enhances thyroglobulin synthesis and exocytosis into follicular lumen and suppresses its resorbtion. It results in sharp drop of blood thyroxine concentration without decrease of deiodinases-mediated thiroxine to triiodothyronine conversion. Stimulation of the lipopolysaccharide-pretreated thyroid gland with thyroid-stimulating hormone increases resorbtion of thyroglobulin and thyroid hormone production. Combined stimulation of the thyroid gland increases protein bound thyroxine and triiodothyronine serum concentration unlike only TSH stimulation resulting in increase of free thyroid hormone levels. It also proves that binding capacity of thyroid hormone serum transport proteins during nonthyroidal illness syndrome remains normal.

[Photodynamic therapy: search for ideal photosensitizer].

Photodynamic therapy (PDT) is a minimally invasive and promising new modality to combat cancer. The method is based on selective accumulation of sensitizers within tumor cells. The high degree of selectivity offered by this modality has been applied for fluorescent diagnostic of cancer. Photosensitization of a tissue-localized sensitizer generates cytotoxic reactive oxygen species as a result the selective destruction of tumor may be achieved. The PDT's major advantages compared to traditional methods of cancer treatment are better selectivity, low skin and general toxicity. This review highlights first and second generations of sensitizers, their photosensitizing abilities and drawbacks. Future developments in PDT will certainly include the discovery of new photosensitizers and a broadening of the applications of the treatment by various means.

[Problems of experimental simulation of hypo- and hyperthyroidism].

This paper reviews main conventional and new experimental models of hypo- and hyperthyroidism. The authors propose classification of methods (physical, chemical, and biological) for modulation of thyroid activity and criteria for life-time and postmortem diagnosis of hypo- and hyperthyroidism. New approaches to simulation of diffuse toxic goiter in animals are considered, advantages and limitations of different models are compared.

Vascular endothelial growth factor in the serum of breast cancer patients.

Here we present the results of comparative immunoenzyme assay of the initial serum levels of VEGF in breast cancer patients (stages T1N0M0 and T2N0M0) and apparently healthy women (controls). It was found that VEGF concentrations in the serum of patients with breast cancer stages T1N0M0 and T2N0M0 significantly surpassed the control levels. Increased levels of VEGF surpassing the threshold values were more often observed in patients with T2N0M0 breast cancer compared to patients with T1N0M0 tumor. At the same time, this marker cannot be used in the diagnostics of this disease because in only 21.4% patients serum level of VEGF surpassed the upper boundary for this growth factor observed in the serum of control women. Serum concentration of VEGF in patients with stages T1N0M0 and T2N0M0 breast cancer did not depend on patient's age and reproductive function and receptor status of the primary tumor (estrogen and progesterone receptors), but was closely associated with tumor histogenesis and differentiation degree. Significantly higher levels of VEGF were observed in patients with lobular infiltrative breast carcinoma compared to patients with ductal tumors and in patients with low-differentiated tumors compared to highly and moderately differentiated tumors. High initial concentrations of VEGF (>300 pg/ml) were more often detected in patients with T2N0M0 breast cancer developing relapses within the first 3 years of follow-up compared to patients without relapses during the corresponding period (p=0.001). These findings suggest that serum level of VEGF in patients with T2N0M0 breast cancer before treatment can be used as an additional marker in parallel with standard clinical and morphological signs of the disease for more precise prognosis of early relapse (during the first 3 years of follow-up).

[Amyloid beta: functional protein or biological junk?].

During a decade there was a dogma that Alzheimer's amyloid beta (Ap) is produced only upon the disease, and that this protein is neurotoxic for neurons and brain tissue. Current scientific evidence demonstrate that AP is an essential molecule in synaptic plasticity that underlie learning and memory. Therefore, it was hypothesized that the change of AP biology in Alzheimer's disease (as well as in a number of other human pathologies, including cardiovascular disease, Niemann-Pick type C disease and Down syndrome) represents a physiological mechanism serving to compensate the impaired brain structure or function. This review summarizes experimental evidence on Abeta as functional player in synaptic plasticity and neurochemical pathways.

[Cholesterol is an important molecule in the processes of the synaptic plasticity and degeneration of neurons].

The importance of homeostasis of neural tissue to neuron functioning, the synaptic plasticity of the hippocampus, and laboratory animals' behavior was demonstrated by the authors earlier. A range of experimental data evidences that cholinergic neurotransmission, ionotropic and metabotropic receptors, excessive tau phosphorylation, alterations in amyloid-beta biochemistry, oxidative reactions, and other features of neurodegenerative processes depend on the precise regulation of cerebral cholesterol metabolism. Such results suggest that disturbances in cholesterol homeostasis are the common primary cause of the sporadic and familial forms of Alzheimer's disease, Down syndrome, Niemann-Pick disease type C, and explain the similarity of neurodegenerative signs in different degenerative diseases of the nervous system. The present work was introduced at an annual conference of American Society for Neuroscience, and is available as a scientific report at www.neurobiologyoflipids.org/content/3/7/.

[Polyamines and mental diseases].

The authors make an attempt to understand and evaluate the role of polyamines in the development of endogenous mental diseases. The article is dedicated to distribution and exchange of polyamines in the central nervous system, their metabolic and regulatory associations with gamma-aminobutyric acid and dopaminergic systems, as well as to possible neuromediatory and neuromodulatory functions of polyamines. The paper is also concerned with effects of psychotropic agents on polyamine metabolism and contains a hypothesis on the role of polyamines in etiopathogenesis of schizophrenia.

[The role of Alzheimer amyloid plaques in the mechanisms of neuron synaptic plasticity disturbance].

The authors studied hippocampal microscopic sections taken from transgenic mice expressing non-mutated human amyloid precursor protein (APP695), and age-matched non-transgenic control mice. The aim of the study was to reveal individual effects of plaque-like amyloid of aged (25.5 months) transgenic mice and diffuse amyloid of non-transgenic mice (verified by immunohistochemistry and Congo Red fluorescence) on synaptic plasticity. In vitro extracellular recording of excitatory postsynaptic potentials from hyppocampal CA1 area revealed impairment of input/output characteristics and long-term potentiation, and a several-millisecond delay of initial post-tetanic traces in aged transgenic vs. control mice. The results show that amyloid plaques (not diffuse amyloid) may be one of the causes of synaptic dysfunction in Alzheimer disease.