Signaling pathways that control the growth and survival of prostate tumor cells in the absence of androgens

Androgen-dependent human prostate adenocarcinoma cell line LNCaP was used to study the effect of androgen deprivation on the cell response to TNF-related cytokines. Several signaling pathways were implicated in cell survival in the absence of androgens. In androgen-deprived LNCaP cells, TNF-alpha and TRAIL stimulated the cell growth and activated the mitogenic and antiapoptotic signaling pathways involving NF-kappa B, STAT3, PI3K, and beta-catenin. The results suggested a role of cytokines in the survival of prostate adenocarcinoma cells deprived of androgens in vitro.     

Enzymes of direct, excision, and corrected systems of repair of higher and lower organisms and their biological roles

DNA repair is of paramount importance to protect the integrity of the cell genome. Over the last decade, DNA repair enzymes have been intensely studied owing to their role in mutagenesis, carcinogenesis, and aging. This led to discoveries of novel enzymes, protein factors as well as their intermolecular complexes involved in the repair process. Alternative pathways of cell response to the same type of damage were identified. Data on the tertiary structure of a number of enzymes and mechanisms of their molecular interaction were obtained. This paper is an overview of latest advances in the research of cell response to DNA damage via direct, base and nucleotide excision, and mismatch DNA repair.     

Genetic defects as markers of tumor development

Carcinogenesis is long-term multistep accumulation of defects of genes responsible for cell division, DNA repair, and apoptosis. The functions of these genes are known both for norm and for pathologies caused by their damage and resulting in "asocial" cell behavior. Owing to the recent progress in studying the mechanisms of carcinogenesis, some genetic defects may be considered from the applied point of view (as tumor markers rather than as pathogenetic factors) and employed in diagnostics. Thus detection of mutant alleles in biological fluids (e.g., beyond the tumor) suggests higher risk of carcinogenesis. Genetic defects are a new class of tumor markers and have a substantial diagnostic potential. In contrast to known protein markers (alpha-fetoprotein, etc.) used in clinical practice, DNA markers are oncospecific (as these are in direct cause-and-effect relationships with carcinogenesis) and universal (as there is not a single tumor cell without a genetic defect). Analysis of DNA markers may be employed not only in diagnostics or tumor growth monitoring (assessment of treatment efficiency, early detection of recurrence or metastasis), but also (prospectively) in screening (tumor detection at the presymptomatic stage, identification of high-risk groups). Theoretical grounds, prospects, problems, and methods of this new field are considered.     

Detection of the DeltaF508 trinucleotide deletion in the human CFTR gene by UV immobilization on nylon of a complex of a PCR fragment with a highly specific probe

Deletion delta F508 has been revealed in PCR-amplified regions of human gene CFTR by color detection of the hybridization complex obtained by ligation of a tandem of short oligonucleotides on a DNA template followed by UV immobilization on nylon. The method allows reliable detection of the three-nucleotide deletion (insertion). The nonspecific signal depends on the nucleotide composition of the biotinylated tandem component. A significant level of the specific signal was achieved by using the PCR-amplified DNA fragments of different length (200-400 bp) irrespective of the position of the tandem-binding site in their sequences.     

Biosynthesis of mini-antibodies to human ferritin in plant and bacterial producers

A recombinant scFv antibody against human spleen ferritin was expressed as a barstar-fused protein in Escherichia coli and in Nicotiana tabacum plants and suspension cell cultures. As demonstrated by immunoblotting with antibarstar antibodies, direction of the recombinant protein to the endomembrane system of plant cells ensured its stability and solubility. Production of the recombinant protein did not differ between parental transgenic plants and their first-generation progeny. Fusion with barstar allowed not only immunochemical detection of the recombinant scFv antibody, but also their purification from the plant material by affinity chromatography with barnase-His6 immobilized on a metal-affinity carrier.     

Method of decomposing spectra using the original spectrum and its derivatives

A method for the decomposition of optical spectra into bands was proposed, which is based on simultaneous approximation of the initial spectrum and its derivatives. The bands of the standard (gaussian) form were used in the decomposition procedure. A method for the selection of the optimal smoothing filter was described. The efficiency of the proposed method was demonstrated on model and experimental absorption spectra. It was shown that this method makes it possible to determine the number of bands and its parameters more exactly than the standard approach based on the analysis of one derivative of one power.     

Study of water exchange in skin tissues by microwave dielectrometry

The complex dielectric permitivity of human skin was measured at a frequency of 42 GHz, and a method for calculating water content in skin tissues in vivo was proposed. The water content reaction of skin to standard physical exercises and nontoxic doses of nicotine was investigated. The functionally related changes in skin dielectric properties were interpreted as structural rearrangements of water contained in blood and tissues fluids.     

Thermodynamic parameters of free oxidation pathways in liver mitochondria

Two pathways of free oxidation in liver mitochondria were examined. One of these pathways is determined by the protonophoric action of free fatty acids, and the other pathway, by passive proton leakage in the absence of fatty acids. According to the model of the proton futile cycle of mitochondria, the protonophoric activity of fatty acids was defined as a quotient of the division of the acceleration of respiration by fatty acid by the coefficient of respiration control for the proton leakage. The temperature dependence of the palmitate protonophoric activity on the Arrhenius plot has a break at 22 degrees C and is characterized by the transition of activation energy from 120 to 60 kJ/mol. The dependence of the respiration rate in state 4 on the Arrhenius plot is linear and, the activation energy is 17 kJ/mol. It was concluded that the first pathway of free oxidation is determined by the cyclic transport of fatty acids with the participation of metabolic carriers, and this process depends on the membrane fluidity; the second pathway is determined by passive leakage of protons through membrane channels, without fatty acids and this process is independent on membrane fluidity.     

The study of the mixing layer by the point image method

The properties of the mixing layer in dynamic systems were studied by the example of a mathematical model of the cubic image type. Its role in the generation of information and the evolution of its significance was shown. At the moment of generation, information is of zero significance, and this significance then increases. A criterion of efficiency was proposed, and the optimum moment of making a decision in creative work was determined. It was shown that the increase in the variability of the parameters of a living system upon entry into the mixing layer and its decrease upon exit can serve as objective indicators of the transition of the system from one dynamic regime (attractor) to another.     

Statistical fluctuations in processes of gene expression regulation: consideration of the problem from point of view of statistical mechanics

The regulation of gene expression is a basic problem of biology. In some cases, the gene activity is regulated by specific binding of regulatory proteins to DNA. In terms of statistical mechanics, this binding is described as the process of adsorption of ligands on the one-dimensional lattice and has a probability nature. As a random physical process, the adsorption of regulatory proteins on DNA introduces a noise to the regulation of gene activity. We derived equations, which make it possible to estimate this noise in the case of the binding of the lac repressor to the operator and showed that these estimates correspond to experimental data. Many ligands are able to bind nonspecifically to DNA. Nonspecific binding is characterized by a lesser equilibrium constant but a greater number of binding sites on the DNA, as compared with specific binding. Relations are presented, which enable one to estimate the probability of the binding of a ligand on a specific site and on nonspecific sites on DNA. The competition between specific and nonspecific binding of regulatory proteins plays a great role in the regulation of gene activity. Similar to the one-dimensional "lattice gas" of particles, ligands adsorbed on DNA produce "one-dimensional" pressure on proteins located at the termini of free regions of DNA. This pressure, an analog of osmotic pressure, may be of importance in processes leading to changes in chromatin structure and activation of gene expression.