[Analysis of VEGF-A/VEGFR1/VEGFR2 gene expression in patients with myelodysplastic syndrome]. / Analiz ékspressii genov VEGF-A/VEGFR1/VEGFR2 u patsientov s mielodisplasticheskim sindromom.

AIM: To assess the significance of gene expression of the vascular endothelial growth factor-A (VEGF-A) and its interacting receptors VEGFR1 and VEGFR2 as potential diagnostic and prognostic molecular markers in patients with myelodysplastic syndrome (MDS). MATERIAL AND METHODS: A real time polymerase chain reaction (RT-PCR) assay was used to investigate the gene expression of VEGF-A, VEGFR1, and VEGFR2 in the mononuclear cell fractions obtained from 24 patients with MDS. RESULTS: The expression of the 3 genes was identified in all the patients examined. There was the highest expression level of the VEGF-A gene (p<0.0001), whereas the expression of the VEGFR1 gene was higher than that of the VEGFR2 gene (p<0.001). The expression of the VEGF-A gene proved to be higher in patients at a higher risk of acute leukemia and positively correlated with the expression levels of the VEGFR1 gene (p<0.05) rather than that of the VEGFR2 gene. At the same time, patients with higher VEGFR1 gene expression had significantly lower overall survival rates (r=-0.5; p<0.05). Patients with intermediate-2 or high-risk acute leukemia showed an increase in the average expression levels of VEGF-A and VEGFR1 and a reduction in VEGFR2 expression. CONCLUSION: This investigation revealed correlations between the number of blast cells in patients with MDS and the expression levels of the VEGF-A gene and between the overall survival of patients with MDS and the expression levels of the VEGFR1 gene rather than those of the VEGF-A and VEGFR2 genes.

[Some molecular and genetic properties of progenitor cells in sarcomas induced with foreign body].

One of the important questions in understanding the mechanisms of carcinogenesis induced with foreign body (or plastic carcinogenesis), is a question about normal progenitor cells in sarcomas (FB sarcomas) appearing in close proximity to the plastic plate implanted under the skin of an experimental animal. There is an assumption in literature that progenitor cells in FB sarcomas originate from vascular endothelium cells feeding a connective tissue capsule that forms around foreign body. In our research, we studied mRNA expression of one of the endothelial cell markers--receptor VEGFR2/FIk1--and growth factor VEGF-A, which interacts with it, in precancerous cells of FB sarcomas in mice. In examined cells, mRNA expression of VEGF-A was found while mRNA expression of VEGFR2/FIk1 was absent. In light of this and formerly established properties of progenitor cells in FB sarcomas, possibilities of the origin of these sarcomas from endothelial cells, pericytes, and pluripotent mesenchymal stem cells are being discussed.

[Gene expression of vascular endothelial growth factors and their receptors in different variants of the course of multiple myeloma].

AIM: To determine the significance of the angiogenic activity estimated from the gene expression of the vascular endothelial growth factors (VEGFs) VEGF-A, VEGF-C, and VEGF-D and their receptors VEGFR1, VEGFRls, VEGFR2, and VEGFR3 in the mononuclear cell fraction of bone marrow (BM) aspirates with tumor plasma cells predominating in different variants of the course of multiple myeloma (MM). MATERIALS AND METHODS: The gene expression of VEGF-A, VEGF-C, and VEGF-D and their receptors VEGFRI, VEGFRls, VEGFR2, and VEGFR3 was determined by reverse-transcription polymerase chain reaction (RT-PCR). RESULTS: VEGF-A, VEGF-C, VEGF-D, as well as VEGFR1, VEGFRls, VEGFR2, and VEGFR3 were expressed showing different intensities in the mononuclear cell fraction of BM aspirates with a predominance of tumor plasma cells in the patients with MM, which allowed patient groups to be identified. In the group of high gene expression of VEGFs and their receptors, the number of clusters of plasma cells and vascular endothelium in the BM aspirates and the degree of osteolysis in the skeletal bones of patients with MM were significantly higher than those in the group of low or absent gene expression. The survival in the latter group was significantly higher. CONCLUSION: The investigation could provide an estimate of angiogenic processes in MM and establish their association with clinical manifestations and cytological characteristics.

[Expression of VEGFA during 1,2-dimethylhydrazine induction of malignant hemangioendothelioma in the renal capsule in mice].

There was examined the role of VEGFA in the induction of malignant hemangioendothelioma (HAE) in the nonvascular tissue of renal capsule (RC) in mice. Expression mRNA VEGFA and its receptor Flk1 in RC and the kidneys in male mice of CBA and C57B1/6 lines was studied at different stages of the administration of a chemical carcinogen 1,2-dimethylhydrazine (DMH), which induced HAE of PC in CBA males with a high frequency, and in C57B1/6 line--with a low frequency. In the kidneys of male mice of both lines at all stages there was observed significant expression both VEGFA and Flk1 but no linear differences were found. In RC of these mice expression of studied genes were not found. Only at the last stage of carcinogenesis in RC of resistant line C57B1/6 and in HAE of RC of line CBA there was appeared weak expression of mRNA VEGFA but mRNA Flk1 was not expressed. A similar profile of expression is appropriate more for pericytes and macrophages but not endothelial cells indicating either on the origin of HAE RC from non-endothelial cells or on atypia of endothelial cells--progenitors of this tumor.

Expression of vascular endothelial growth factor receptors VEGFR1 in cultured multiple myeloma cells: correlation with immunophenotype and drug resistance.

We studied the expression of genes encoding vascular endothelial growth factors VEGF-A, VEGF-C, VEGF-D and their receptors in cell cultures of human multiple myeloma IM9, RPMI 1640, RPMI 8226. The studied cells did not differ by the expression of growth factors. Expression of VEGFR1 receptor was detected only in IM9 cells and VEGFR2 and VEGFR3 receptors were not expressed in multiple myeloma cells. A dependence between the aberrant CD45/CD56 phenotype of human multiple myeloma cells and VEGFR1 expression in them was revealed. The only VEGFR1-positive IM9 cell culture was most resistant to Velcade (bortezomib).

Mechanisms of angiogenesis.

Tissue activity of angiogenesis depends on the balance of many stimulating or inhibiting factors. The key signaling system that regulates proliferation and migration of endothelial cells forming the basis of any vessel are vascular endothelium growth factors (VEGF) and their receptors. The VEGF-dependent signaling system is necessary for formation of the embryonic vascular system. Neoangiogenesis during tumor growth is also associated with activation of this signaling system. The biological significance of the effect of such system on the cells depends on the content in tissue of various factors of the VEGF family and their receptors, while in the case of VEGFA it is defined by the ratio of different isoforms of this growth factor. A number of other signaling systems are also involved in regulation of the main steps of vessel formation. The signaling system Dll4/Notch regulates selection of endothelial cells for beginning of angiogenic expansion by endowing particular properties to endothelial cells leading in this process. An important step in vessel stabilization and maturation is vascular wall formation. Signaling system PDGFB/PDGFRbeta as well as angiopoietins Ang1, Ang2, and their receptor Tie2 are involved in recruiting mural cells (pericytes and smooth muscle cells). Identification of key molecules involved in the regulation of angiogenesis may provide new possibilities for development of drugs suitable for inhibition of angiogenesis or its stimulation in various pathologies.

[Effect of sex hormones on the 1,2-dimethylhydrazine metabolic activity in the kidneys of CBA-strain mice]. / Vliianie polovykh gormonov na aktivnost' metabolizma 1,2-dimetilgidrazina v pochkakh myshei linii CBA.

1,2-dimethylhydrazine (DMH) metabolizing activity of kidney microsomes was shown to be two times higher in male, than in female CBA mice. Castration decreased DMH metabolizing activity of male kidney microsomes to the females' level. DMH metabolizing activity of castrated males treated with testosterone propionate was identical to that of intact males. The incorporation of 14C-DMH into kidney DNA was also higher in male, than in female CBA mice.

[Specificity of cytochrome P-450 isoforms contained in endoplasmic reticulum membranes and nuclear membranes in relation to benzo(a)pyrene]. / Spetsifichnost' izoform tsitokhroma P-450, soderzhashchikhsia v membranakh éndoplazmaticheskogo retikuluma i iadernykh membranakh, po otnosheniiu k benz(a)pirenu.

The metabolic activation of benz(a)pyrene (BP) catalyzed by rat liver microsomes and isolated liver nuclei in the presence of certain inhibitors of the monooxygenase system was studied. Several forms of cytochrome P-450 are supposed to participate in metabolic conversion of BP. The specificity of cytochrome P-450 isoforms contained in the endoplasmic reticulum and in nuclear membranes is discussed.

[Role of supranucleosomal structures of chromatin in the uneven distribution of DNA-bound 7,12-dimethylbenz(a)anthracene metabolites formed in vivo or in the perfused rat liver]. / Rol' nadnukleosomnoi struktury khromatina v neravnomernom raspredelenii sviazannykh s DNK metabolitov 7,12-dimetilbenz(a)antratsena, obrazuiushchikhsia in vivo ili v perfuziruemoi pecheni krys.

It was demonstrated that the DNA closely associated with the nuclear matrix preferentially binds 7,12-dimethylbenz(a)anthracene (DMBA) metabolites. In experiments with perfused rat liver, it was found that the kinetic curves for adduct formation in all DNA fractions of DNP have maxima, the largest differences in the rate of metabolite binding in the DNA fractions being observed at the initial moment of perfusion. There is evidence that the preferential binding of DMBA metabolites to matrix DNA is due to the increased accessibility of the DNA to the metabolites rather than to its proximity to the nuclear membrane. This accessibility, in its turn, is due to the peculiarities of the supranucleosomal structure of transcriptionally active DNP fragments associated with the nuclear matrix.

[Influence of the rhythm and route of 1,2-dimethylhydrazine administration on its carcinogenic effect in mice]. / Vliianie ritma i puti vvedeniia 1,2-dimetilgidrazina na ego kantserogennyi éffekt u myshei.

Effects of route of administration (subcutaneous, intraperitoneal, by stomach tube and with drinking water) and dose fractionation on the carcinogenicity of 1,2-dimethylhydrazine (DMH) were studied in CBA and (C57B1/6j X CBA)F1 mice. Fractionation of DMH dose given subcutaneously exerted different effects on tumors at various sites: decrease of colon and anal tumor incidence, increase of vascular liver tumors and renal adenomas and no influence on hepatoma, lung adenoma and uterine sarcoma induction. When given with drinking water, DMH did not induce colon and anal tumors but produced high incidence of vascular neoplasms. No such effect was observed when DMH was administered weekly by stomach tube. Alteration of the organotropism of DMH given with drinking water is attributed by authors to the decrease of single DMH dose and not to peroral route of administration.

[State of the monooxygenase enzymatic system during chronic diethylnitrosamine administration]. / Sostoianie monooksigenaznoi fermentnoi sistemy pri khronicheskom vvedenii diétilnitrozamina.

Content of components and functional activity of monooxygenase enzyme system were studied in rat liver tissue during hepatocarcinogenesis produced by diethyl nitrosamine treatment. Content of cytochromes P-450 and b5, NADPH- NADH-cytochrome c reductase and demethylase activities as well as capacity to induce the monooxygenase enzyme system after administration of its inductors were not altered in chronic treatment with carcinogenic doses of diethyl nitrosamine. The higher doses of the amine were shown to reduce the content of the cytochromes in liver tissue.

[Characteristics of DNA during binding with polycyclic aromatic hydrocarbons in vitro]. / Kharakteristika DNK v protsesse sviazyvaniia politsiklicheskikh aromaticheskikh uglevodorodov in vitro.

Polycyclic aromatic hydrocarbons (PAH) were covalently bound to DNA by means of various activating systems. The following systems were used: the microsomal fraction of the rat liver, the system with I2, the system with ascorbic acid and FeSO4. Breaks in DNA due to the activating systems action appeared in all of these systems. Plateau of the PAH binding system curve in the microsomal system cannot be attributed either to the fall of the PAH metabolism rate to zero, or to the PAH binding sites in DNA. This plateau is the result of equalization of the rates of the two contrary-directed processes: the binding of metabolites and their removal due to DNA degradation. Because of the breaks in DNA caused by the activating systems, the authors failed to discover the changes in sedimentation data of DNA due to the covalently bound PAH.

[Interaction of electrophilic alkylating agents with nucleophilic sites of mitochondria]. / Vzaimodeistvie elektrofil'nykh alkiliruiushchikh agentov s nukleofil'nymi tsentrami mitokhondrii

The electrophilic alkylating agents having different numbers of electrophilic groups with nucleophilic sites of mitochondria were studied. Bifunctional compounds were found to modify the structure of mitochondria so that some of the sulfhydryl groups become inaccessible for titrating ions of Ag+. Monofunctional agents caused no changes in the number of determinable sulfhydryl groups and prevented the effect of bifunctional compounds. The linkage formed between the electrophilic residue and the nucleophilic site is stable in the absence of electron transport. During the transport of electrons in the respiratory chain the linkage becomes labile and the electrophilic residue chips off. A scheme of interaction of electrophilic alkylating agents with nucleophilic sites of mitochondria is proposed.