Correlation between Expression of KLF5 and ZEB1 Transcription Factor Genes in Pancreatic Cancer.

The mRNA content of the transcription factors KLF5 and ZEB1 was studied in pancreatic tumor tissues and in fetal and normal pancreas. Transcription of these factors was not high and similar in normal and fetal pancreatic tissues but greatly increased in the pancreatic ductal adenocarcinoma tissues. A significant positive correlation between the KLF5 and ZEB1 transcription levels in the pancreatic tumor tissues was observed.

PDX1: A Unique Pancreatic Master Regulator Constantly Changes Its Functions during Embryonic Development and Progression of Pancreatic Cancer.

Multifunctional activity of the PDX1 gene product is reviewed. The PDX1 protein is unique in that being expressed exclusively in the pancreas it exhibits various functional activities in this organ both during embryonic development and during induction and progression of pancreatic cancer. Hence, PDX1 belongs to the family of master regulators with multiple and often antagonistic functions.

Dependence of expression of regulatory master genes of embryonic development in pancreatic cancer cells on the intracellular concentration of the master regulator PDX1.

Exogenous expression of the gene encoding the pancreatic master regulator PDX1 in cell lines with different degrees of differentiation of pancreatic cancer cells is accompanied by changes in the expression of known master genes involved in cancer progression. In BxPC3PDX+ cells, as compared to BxPC3PDX-, we detected an increased expression of the following genes: NKX6.1 (2 times), NR5A2 (2.5 times), KLF5 (1.8 times), ZEB1 (3 times), and ONECUT1 (1.3 times), as well as a decreased expression of MUC1 and SLUG genes (3 and 2 times, respectively). In PANC1PDX+ cells, as compared to the control PANC1PDX- cells, we detected a decreased expression of ISL1 (2 times) and an increased expressed of KRT8 (2 times) and MUC1 (by 30%). In the high-grade cell lines (including the BxPC3 line studied), the total content of sites containing the marks of active enhancers was higher than that in the low-grade cell lines (PANC1).

[An effect of disease-modifying drugs on the development of children born to mothers with multiple sclerosis]. / Vliianie na razvitie rebenka terapii preparatami, izmeniaiushchimi techenie rasseiannogo skleroza, u materei s rasseiannym sklerozom.

AIM: To evaluate an effect of mother's treatment with disease-modifying drugs (DMD) on the mental and physical development of the child in the first year of life. MATERIAL AND METHODS: Thirty pregnancies resulted in birth of live babies in patients with multiple sclerosis (MS) were studied. The diagnosis of MS was made to the mother before conception of the child. Seven mothers did not receive DMD at the moment of conception (controls), 13 mother were treated with interferon-beta (IFN) and 10 with glatiramer acetate. A structure interview, examination of the child with the assessment of common anthropometric indices, the WHO scale for achievement of six milestones, medical history and statistical analysis were used. RESULTS AND CONCLUSION: The data on the negative effect of MS on the growth and development of the fetus and the positive impact of treatment of the mother with DMD in the early stages of pregnancy on anthropometric indices and development of the child in the first year of life were confirmed. It has been concluded that DMD positively influence the disease course of the female patient and potentially improve the prognosis for her future offspring.

[ADULT STEM CELLS AND CELLS OF MALIGNANT ORIGIN. PART I].

Recent data on adult stem cells are reviewed. According to the present dominant paradigm, it is most probable that cancer predisposition arises or cancer is initiated in these cells.

[Master Transcription Regulators Specifying Cell-Lineage Fates in Development As Possible Therapeutic Targets in Oncology].

The transformation of normal precursors into cancer cells is an intricately regulated, multistep process. The master regulatory genes that play a crucial role in the process of organism development may also play a key role in carcinogenesis. From such a point of view, cancer is not simply a genetic disease that is due to a progressive accumulation of mutation--it is also a disorder of the developmental system of the tissue in which cancer emerges. Master regulators and their genes disturb stem cell differentiation upon mutation and thus may serve as targets for cancer therapy, in addition to the classic oncogenes and suppressors of tumor formation. This review is an attempt to give a modern concept of master genes and their functions in adult stem cells of the organism and in carcinogenesis, with pancreatic cancer as an example.

Cancer Stem Cells: Plasticity Works against Therapy.

Great successes in identification and deciphering of mechanisms of the adult stem cells regulation have given rise to the idea that stem cells can also function in tumors as central elements of their development, starting from the initial stage and continuing until metastasis. Such cells were called cancer stem cells (CSCs). Over the course of intense discussion, the CSCs hypothesis gradually began to be perceived as an obvious fact. Recently, the existence of CSCs has been indeed confirmed in a number of works. However, when are CSCs universal prerequisites of tumors and to what extent their role is essential for tumor evolution remains an issue far from resolved. Likewise, the problem of potential use of CSCs as therapeutic targets remains unsolved. The present review attempts to analyze the issue of cancer stem cells and the potential of targeting them in tumor therapy.

[Pioneer Transcription Factors in Normal Development and in Carcinogenesis].

Pioneer transcription factors constitute a heterogeneous group of regulatory proteins of animals, which, unlike other transcription factors, are able to recognize and bind target DNA sequences within closed chromatin. This binding can change the local chromatin structure and facilitate binding of other proteins, thus establishing competence for gene expression. The ability to bind silent genes in the closed environment makes the pioneer factors very useful in the processes leading to cardinal alteration of cell phenotype, such as differentiation in embryonic development or cell reprogramming. These proteins can remain bound to target sequences during mitotic division, and due to this probably take part in the maintenance of cellular memory. Apparently, pioneer transcription factors are active participants in carcinogenesis and maintenance of tumor cell phenotype, although their role in these processes needs additional research. It is reasonable to suppose that a further study will help to shed more light on the genetic processes in embryonic development, increase the efficiency of cell reprogramming and also develop new approaches to diagnostics and therapy of cancer diseases.

[ADULT STEM CELLS AND CELLS OF MALIGNANT ORIGIN. PART II].

Recent data on adult stem cells are reviewed. According to the present dominant paradigm, it is most probable that cancer predisposition arises or cancer is initiated in these cells.

[Comparative analysis of activity of different promoters for NIS gene expression in melanoma cells].

Development of targeted drug delivery system is key problem of cancer gene therapy. To ensure specific delivery of these therapeutic compounds to the tumor it is preferable for therapeutic gene expression to occur predominantly in cancer cells. Therefore, when testing drug in vivo, it is necessary to study distribution of therapeutic gene expression products in different tissues of the organism. Sodium iodide symporter (NIS) is attractive reporter because its tissue level is easily quantitatively detected by noninvasive imaging methods. Different promoters are used to direct expression of therapeutic genes in tumor cells: strong nonspecific, moderate tissue-specific and tumor-specific. Tumor-specific promoters function in wide range of tumor cells, however they are relatively weak. Relationship between promoter and sodium iodide symporter activity is unclear to date. In this report we examined activity of different promoters in two melanoma cell lines, functional activity of NIS driven by these promoters, also we compared promoter strength and NIS activity. We demonstrated that in spite of strong differences in promoter activity functional activity of NIS directed by these promoters varies weakly. Relatively weak melanoma-specific promoter directs high NIS activity in melanoma cell, however weaker cancer-specific promoters drive high NIS activity only in certain melanoma cell line.

[Quantitative comparison of expression for genes linked in bicistronic vectors via ires or 2A-peptide of porcine teschovirus-1 sequence].

Simultaneous expression of multiple target genes is often required in biotechnology. Multicistronic vectors coding for several proteins are being actively developed for this purpose. In commercially available vectors different variants ofencephalomyocarditis virus internal ribosome entry site (IRES EMCV) are used most often. However, many researchers consider that utilization ofself-cleaving 2A peptides sequences within multi- and bicistronic vectors is more promising. In this work, we compared the efficiency of gene expression in cells transfected with bicistronic vectors based on IRES EMCV and 2A peptide sequence derived form porcine teschovirus-1 (P2A). Efficiency ofgene expression was determined in three mammalian cell lines by measurement of co-expression levels of genes coding for RFP and EGFP proteins linked by IRES or P2A sequence. Higher level oftransgene expression was exhibited by cells transfected with the vector containing the 2A peptide sequence.

Promoters with cancer cell-specific activity for melanoma gene therapy.

Melanoma is one of the most aggressive tumors. It develops from pigment-forming cells (melanocytes) and results in a high number of lethal outcomes. The use of genetic constructs with the ability to specifically kill melanoma cells, but not normal cells, might increase the lifespan of patients, as well as improve their quality of life. One of the methods to achieve a selective impact for therapeutic genes on cancer cells is to utilize a transcriptional control mechanism using promoters that are specifically activated only in cancerous cells. In this review, promoters of the genes that are preferentially expressed in melanoma cells are described. These promoters, and other highly melanoma-specific regulatory elements, reduce the unspecific expression of therapeutic genes in normal tissues. Moreover, cancer-specific promoters and their elements are advantageous for the development of universal anticancer drugs. Examples of the use of double promoters that have a high potential as instruments in cancer gene therapy are also given in this review.

[Functional analysis of the HERV-K LTR residing in the KIAA1245/NBPF subfamily].

Long terminal repeats (LTRs) of human endogenous retrovihuses (HERs) might affect transcription regulation of neighboring genes. In our previous study, we showed that the solitary LTR residing in the KIAA1245/NBPF gene subfamily displayed high enhancer activity in a transformed embryonal carcinoma cell line Tera1. In this study, we performed a functional dissection of the LTR and studied its deletion series. Using transient transfection assay, we confirmed the ability of the LTR to drive the expression of the luciferase reporter gene in Teral cells. At the same time, in two other transformed cell lines tested, NGP and NT2/D1, the full-size LTR and its fragments showed no or low enhancer activity, thus demonstrating cell type specificity of the LTR enhancer activity. The functional dissection of the LTRrevealed a specific region within the U3 part appeared to be responsible for the enhancer properties. We showed that the identified enhancer was able to work in a highly cell type specific manner. The data obtained are in line with the hypothesis suggesting that KIAA1245/NBPF LTR may affect the regulation of the KIAA1245/NBPF subfamily genes transcription.

Enhancer element potentially involved in human survivin gene promoter regulation in lung cancer cell lines.

We have revealed evolutionarily conserved regions in a 4500-bp DNA sequence 5'-adjacent to the survivin (BIRC5) gene. In the transcribed region of the BIRC5 gene we have detected and characterized in detail a 3'-fragment of the CpG island that stimulated in enhancer-like way the gene promoter activity in normal cells and in a number of cancer, in particular lung cancer, cell lines. When added to the initial 1498-bp survivin promoter region, a transcribed DNA fragment of a CpG island approximately twofold enhanced the promoter activity in cancer cells and in normal lung fibroblasts. The observed effect did not depend upon the orientation of the fragment and distances between the fragment and the transcription initiation site. In the case of a heterologous SV40 virus promoter, the effect was less pronounced. In addition to earlier reports, the results provide new information on the BIRC5 gene expression regulation and also demonstrate that this gene exon sequences can play a significant role in BIRC5 gene expression regulation. The data provide another possibility to increase survivin promoter activity without changing its cancer specificity for application in cancer (in particular, lung cancer) gene therapy.

Cellular and molecular phenotypes of proliferating stromal cells from human carcinomas.

BACKGROUND: Stromal cells are a functionally important component of human carcinomas. The aim of this study was to obtain and characterise primary cultures of stromal cells from human carcinomas and the corresponding surrounding normal tissue. METHODS: Primary stromal cell cultures from tumours of lung, oesophagus and pancreas were obtained using a mild tissue dissociation method and a medium for culturing mesenchymal cells. Immunofluorescence staining and western blotting were used to analyse the expression of differentiation markers and selected known oncoproteins in the cell cultures obtained. RESULTS: A panel of stromal primary cultures was prepared from different human tumours and from matched normal cancer-free tissues. The in vitro proliferative potential of tumour-associated fibroblasts was shown to be higher than that of matched normal stromal cells. A mutational analysis of the TP53 and KRAS2 genes in a number of stromal cultures did not reveal known mutations in most cells of the cultures studied. Western blot analysis showed that stromal cells of lung tumours were characterised by a statistically significantly lower expression level of the p16 protein as compared with that in normal lung stromal cells. An important finding of our study was that, according to immunofluorescence assay, a fraction of fibroblast-like vimentin-positive cells in some tumour and normal stromal cell cultures expressed an epithelial marker - cytokeratins. CONCLUSIONS: Proliferating stromal cells from the carcinomas studied proved to be genetically normal cells with altered expression profiles of some genes involved in carcinogenesis, as compared with normal stromal cells. Epithelial-mesenchymal transition may lead to the emergence of transdifferentiated fibroblast-like cells in tumour stroma and in the tumour-surrounding tissue.

Identification of some human genes oppositely regulated during esophageal squamous cell carcinoma formation and human embryonic esophagus development.

Here we directly compared gene expression profiles in human esophageal squamous cell carcinomas and in human fetal esophagus development. We used the suppression subtractive hybridization technique to subtract cDNAs prepared from tumor and normal human esophageal samples. cDNA sequencing and reverse transcription polymerase chain reaction (RT-PCR) analysis of RNAs from human tumor and the normal esophagus revealed 10 differentially transcribed genes: CSTA, CRNN, CEACAM1, MAL, EMP1, ECRG2, and SPRR downregulated, and PLAUR, SFRP4, and secreted protein that is acidic and rich in cysteine upregulated in tumor tissue as compared with surrounding normal tissue. In turn, genes up- and downregulated in tumor tissue were down- and upregulated, respectively, during development from the fetal to adult esophagus. Thus, we demonstrated that, as reported for other tumors, gene transcriptional activation and/or suppression events in esophageal tumor progression were opposite to those observed during development from the fetal to adult esophagus. This tumor 'embryonization' supports the idea that stem or progenitor cells are implicated in esophageal cancer emergence.