In the present study we have applied the siRNA approach for substantial reduction of AML1-ETO and RUNX1 (K83N) expression, which are frequently found in the leukemic cells. We have designed small hairpin RNAs (shRNA) for targeting AML1-ETO oncogene and a region close to the 5'-untranslated region of mRNA for the mutant RUNX1 (K83N) oncogene and expressed the shRNAs in lentiviral vectors. We report a stable reduction in expression of the oncogenes following the introduction of shRNAs into cells.

Breast cancer is the most incident cancer among women. We investigated the role of polymorphisms of folate metabolizing genes MTHFR (C677T and A1298C), SHMT1 (C1420T) and MTHFD (G1258A) in genetic susceptibility to this type of cancer. We determined allele and genotype frequencies in case (850 women with sporadic form of breast cancer) and control (810 women) groups. None of these polymorphisms was significantly associated with breast cancer risk. To increase statistical power of our study, we conducted a meta-analysis which included published genotype data and the results of our work. Meta-analysis also revealed no significant association of studied SNPs with breast cancer.

In this study cytostatic and chemosensitizing actions of gestagens are described. Cytostatic mechanisms can be divided into estrogen-mediated and independent ones. The former include down-regulation of estrogen receptors, induction of 17?-hydroxysteroid dehydrogenase and estron sulfotransferase. The latter are MAP-kinase inhibition, induction of cell differentiation and apoptosis. Chemosensitization by gestagens is due to inhibition of P-glycoprotein, GST and MRP. Another putative chemosensitization mechanisms involves mitochondrial transition pore (MTP), at least for such gestagens as buterol and acetomepregenol. Elucidation of common mechanisms of MTP and MDR regulation and the possible role of MTP in chemosensitization is a new direction of investigations into the action of steroid hormones.

Twenty samples of benign pigmented neoplasms of the skin, including 9 intradermal nevi and 11 complex ones, were investigated. Fluorescence in situ hybridization was used to detect the copy number of the RREB1 (6p25), MYB (6q23), and CCND1 (11q13) genes. Analysis of the findings revealed no significant changes characteristic of melanoma in the nevi. However, the authors established that there was a direct correlation between the copy number of the MYB and RREB1 genes and that the amount of the MYB gene most frequently deviated from the normal values. In addition, a relationship was found between the number of MYB gene copies and the depth of the epidermal layer. In cases of an intradermal nevus, the copy numbers of the CCND1 and MYB genes were shown to vary more greatly than in cases of a complex nevus.

Mutations in the genes of corrective 3' --> 5'-exonucleases as well as in DNA polymerases lead to decrease in DNA biosynthesis accuracy all over genome. This is accompanied by the increase in mutagenesis and carcinogenesis probabilities. In this work, the activities of 3' --> 5'-exonucleases and DNA polymerases were studied in the extracts from normal and cancer cells of rodents and humans, and we are the first to measure their integral ratios. As example, in cultivated dermal fibroblasts of an adult human, the value of the ratio of activities of 3' --> 5'-exonucleases to DNA polymerase activity (3'-exo/pol) surpassed several folds the such a value for HeLa cells. Similar picture was observed during the comparison of normal fibroblasts of rat embryos and transformed fibroblasts of Chinese hamster A238. Experiments with cell-free extracts of some organs from healthy rats of various ages have shown that normal proliferating cells demonstrate higher 3' --> 5'-exonuclease activity and higher values of 3'-exo/pol that quiescent cells. Comparison of these data suggests a violation of the function of corrective 3' --> 5'-exonucleases in abnormally growing cancer cells.

The available data on effect of various environmental carcinogenic factors (chemical mutagens, polycyclic aromatic hydrocarbons, nitroso compounds, aromatic amines, tobacco smoking, ionizing radiation, constant illumination, alimentary obesity) upon the organisms suggest that it induces standard pattern of changes at different levels of integration (molecular, cellular, systemic) similar to characteristics of accelerated aging. These changes are favorable to development of age-associated diseases, including cardiovascular those, malignancies, diabetes mellitus type 2, metabolic syndrome, decrease in resistance to stress, immunodepression which lead to life span reduction and premature death.

One of the phenotypic effects of mutation in the Hr gene in mice is disintegration of hair follicles and their degeneration into open funnel-shaped structures (utricles) opened on skin surface and cysts located in the depth of the dermis. The aim of the current study consists in analysis of the process of reparative regeneration of skin in homozygotous mice with one of the mutant alleles of the Hr gene-Hr(hr). It is shown that epithelial cells that constitute the inner pavement of cysts take part in the process of epithelization of deep skin wounds. This indicates that the competence of ectodermal cells in relation to inductive signals from injured skin remains in Hrr homozygote mice, in spite of the significant anatomic abnormalities of the hair follicles.

The influence of T-cadherin on the pigmentation and proliferation of mouse melanoma B16F10 cells in vitro and on the growth and neovascularization of tumor cell masses formed by the B16F10 cells in a model of the chorioallantoic membrane of a chicken embryo is studied. It is found that the proliferative activity of the cells decreases in the cell culture of mouse melanoma upon the hyperexpression of T-cadherin in comparison with the cells in the control. It is shown in experiments in vitro that the B16F10 cells with the hyperexpression of T-cadherin are less adaptive to the chorioallantoic membrane than the control cells. In addition, it is found that the control cells of mouse melanoma form tumors with area more 0.1 mm2 more often than the cells with the hyperexpression of T-cadherin and the amount of the vessels growing to tumor cell masses formed by the cells with the hyperexpression of T-cadherin is significantly lower than the same index for the cells in the control. Thus, the hyperexpression of T-cadherin in the B16F10 cells suppresses the proliferation of these cells in vitro and the growth of the tumor masses formed by melanoma cells on the chorioallantoic membrane and their neovascularization in vivo are demonstrated.

to reveal the determinants of the development of iron overload in patients with acute leukemias (AL) and aplastic anemia (AA).

There are data that show that under the influence of chemical carcinogens of various classes (polycyclic aromatic hydrocarbons, nitroso compounds, aromatic amines), mutagens, ionizing radiation, extremely low frequency radio waves, constant illumination, tobacco smoking, the development premature hotmonal-metabolic disturbances in the main homeostatic systems (nervous, endocrine, immune and energy) similar to these developed during the normal aging have a place. These disturbances facilitate the realization of promotion and progression stages ofcarcinogenesis. Geneticall modified animals (mutants, transgenic or knockout) open new opportunity for the analyses of the role of separate genes in the relationships between natural and accelerated by the exposure to environmental factors aging. The increase in tumor incidence usually observed in genetically modified mice with phenotypical features of premature or accelerated aging whereas in animals revealed the delayed aging the increase of tumor latensy and/or decrease of tumor incidence have observed. The treatment with geroprotectors of member of populations at risk of accelerated aging induced by environmental factors may serves as effective means of primary cancer prevention.

Mucosa-associated lymphoid tissue (MALT) conception has been extensively developing for last 20 years.

Tumor-specific promoters are predominantly active and ensure expression of the gene under control exclusively in cancer cells. However, a low activity of the promoters is an essential disadvantage for their therapy usage. To achieve a higher expression level of the therapeutic gene, herpes simplex virus thymidine kinase (HSV-tk), the Tat-TAR-system being utilized by HIV-1 for increasing own gene expression was developed. A potentiating activity of tat gene under control of two different cancer-specific gene (human survivin gene and human telomerase reverse transcriptase) promoters for increasing of the HSV-tk gene expression being regulated by TAR-element was evaluated, and activity of the cancer-specific promoters in the Tat-TAR-system was compared. Co-transfection of the cells with the both constructions led to the tat protein synthesis and its affect the HIV-1 TAR-element. An expression level of HSV-tk gene ensured by the both promoters in the binary system was close to that for strong non-specific cytomegalovirus (CMV) promoter. Enzymatic activity of HSV-tk protein in cells having both elements of Tat-TAR-system was two orders of magnitude higher than that in the cells transfected with HSV-tk gene under control of the cancer-specific promoter. Notably, the effect was independent of p53-status of transfected cells: HSV-tk expression level was almost the same in p53(+) and p53(-) cells. The obtained results show that system may be used for therapy of different cancer types both p53-defective and p53-positive ones inhibiting cancer-specific promoters activity.

Leukemia is a heterogeneous group of malignant blood diseases, it could be characterized by the expansion of immature blast cells. It's still stay unknown the point molecular mechanism of leukemogenesis. It has been previously found that leukemia patients frequently have the mutations in genes responsible for normal proliferation and differentiation of hematopoietic stem cells. At present, scientific groups worldwide engaged in biomedical studies of structural and functional aspects of leukemic oncogenes and their role in human and beast leukemogenesis. In this review we describe the most recent conceptions of molecular properties of oncogenes activation of which may lead to the development of CBF-AML, in case of mutation in core-binding factors AML1 (CBFalpha) or CBFbeta.

Transcription factor Nrf2 plays a key role in cell defense against oxidative stress, as well as in counteracting chemical and physical factors that induce apoptosis and carcinogenesis. The mechanism of Nrf2/ARE redox regulation and ARE-mediated gene expression are analyzed in the review. Special attention was paid to anti-inflammatory effects of Nrf2/ARE system, which significantly manifest in Nrf2 knockout animal.

Analysis of chromosomal abnormalities in bone marrow cells in 116 children with diagnosis of acute myeloid leukemia (AML) was performed. Frequency of evolution of clonal chromosome abnormalities in AML constituted 42,3%. The most abundant among them were numerical abnormalities of chromosomes 8, 9, and 21 as well as secondary structural abnormalities in region 12p12, 9p22, 9q22, 9q34, 11q14-23, and 16q22. Numerical abnormalities were registered in 26,7% cases. The basic mechanism of leukemic clone evolution was trisomy, deletion and monosomy. The frequency of evolution was 7 times higher in the age group up to 2 years and twice higher in the age group up to 5 years. The high frequency of evolution was established at t(15;17)(q22;q22) and the absence at inv(16)(p13q22). The patients with clonal evolution died earlier, before reaching remission, that can be connected with heavy initial state and high frequency of relapse. Conception of abnormality clone evolution was proposed at some stages: I--appearance of balanced rearrangement; II--trisomy; III--lose of chromosomal material. Appearance of unbalanced genome in evolution possess an advantage in proliferate activity and can be connected with the answer on chemotherapy. Identity of abnormal chromosome structure at diagnosis and relapse of disease can be an evidence of the influence of chemical agent on establishment of some types of evolution of chromosome abnormalities in leukemic cells in AML in children.

Identification of proteins that can be therapeutically targeted is an important problem in molecular biology. Transcriptomics approaches such as coexpression network analysis have been previously proposed as tools facilitating drug targets discovery. To assess whether coexpression network analysis is applicable to prediction of novel anticancer drug targets, we compared known targets of 103 antineoplastic drugs with those of 776 drugs irrelevant to cancer in terms of their position in the coexpression network of glioblastoma--one of the most malignant human cancer types. Affymetrix GeneChip expression data for 93 glioblastoma surgery samples were analyzed. We were able to identify coexpression modules associated with such processes as proliferation, immune response, neurotransmission, ATP synthesis, extracellular matrix formation and others. Anticancer drug targets were fourfold over-represented in the coexpression module associated with cell proliferation and mitosis relative to the other modules. Network connectivity of drug targets within the mitotic module was found to be highly correlated with the number of anticancer drugs acting upon them. Our results support the hypothesis that hubs in the mitotic module represent potential anticancer drug targets, and confirm applicability of coexpression network analysis to anticancer drug targets identification.

Amplification of intermethylated sites (AIMS) is a powerful tool for differential methylation screening of genomes. Its applications have nevertheless been limited until recently for the absence of systemic approach to AIMS experimental design and of appropriate computer software for the analysis of AIMS results. We have developed AIMS in silico computer suggestion tool capable of predicting possible experimental outcomes, which assists in designing AIMS experiments depending on the research aims and available instrumentation, and in analyzing experimental results from the point of view of genomic locations of the DNA fragments under study. With AIMS in silico we have characterized qualitatively and quantitatively AIMS products obtainable under different conditions; to ease experimental design we demonstrate AIMS products hierarchical structure. We discuss examples of designing AIMS experiments and results analysis as well as possible relative to AIMS alternative approaches to differential methylation screening. AIMS in silico computer software is intended to standardize AIMS applications and to turn it into one of the principal approaches towards cancer epigenomes studies as well as towards diagnostics in oncology, including early screening.

To estimate diagnostic value of K-ras mutations during cancer risk group formation, they were studied in the samples of sporadic carcinomas (n = 33) and malignant (n = 13) polyps of large intestine obtained during surgery or polypectomy. Using PCR analysis, restriction analysis, SSCP analysis and automated sequencing, eight various point mutations were revealed. Six of them were located in codon 12 and two, in codon 13 of the K-ras gene. Mutation frequency in carcinomas, benign and malignant polyps was 43, 49, and 69%, respectively. In the healthy tissue of the large intestine, no changes in codons 12 and 13 in the K-ras gene were observed. Mutations in the groups of Russian patients examined partially overlapped. In patients with colorectal carcinoma the mutation frequency in the K-ras gene was not associated with disease onset age, location, and the extent of tumor differentiation while it was associated with the stage of tumor process. The maximum mutation frequency was revealed in polyps of patients over 70 years of age as well as in the adenomas of villous histology and large size ((1 cm). No correlation between the K-ras mutation frequency and the extent of polyp dysplasia was observed.

Sequential treatment of bisulfate-converted DNA was used to study methylation of promoter areas of SEPT9, HLTF, ALX4 and CDH1 genes. Methylation profiles were evaluated by comparing bioptical findings on colorectal cancer (n=55) and morphologically intact areas of the large bowel (n=71). Significant differences between groups were established for SEPT9, HLTF and ALX4 genes (p < or = 10(-9)) in evaluating medium-rate methylation of CpG. Diagnostic sensitivity (Se) peaked for SEPT9 (78 +/- 7%); specificity--(86 +/- 4%) (Sp). On site CpG (position "+14"), similar findings were reported: Se=81 +/- 6%, Sp=77 +/- 5%. Therefore, CpG(14)SEPT9 may be used as a separate marker. As a result of the use of HLTF as marker on all 23 sites, Se was 67 +/- 6% and Sp--87 +/- 3%; ALX4 diagnostic sensitivity--59 +/- 6%. Specificity level was similar to those of the other genes (88 +/- 3%). Despite the role of CDH1 gene in colorectal cancer, the group-to-group differences in methylation rates were minimal. Such values of Se and Sp as 54 +/- 6% and 67 +/- 5%, respectively, could not support methylation of the CDH1 promoter area for diagnostic purposes. Therefore, combined evaluation of SEPT9, HLTF and ALX4 genes offered more advantage as far as diagnosis is concerned. Hypermethylation in two of the three genes was assumed as a criterion for diagnosis. Under such conditions, diagnostic sensitivity was 81 +/- 7% (Sp=93 +/- 3%). With such high values, the criterion has a potential of being instrumental in working out diagnostic tests for colorectal cancer.