[Key molecular mechanisms associated with cell malignant transformation in acute myeloid leukemia].

Cancer, along with cardiovascular disorders, is one of the most important problems of healthcare. Pathologies of the hematopoietic system are the most prevalent in patients under 30 years of age, including acute myeloid leukemia (AML), which is widespread and difficult to treat. The review considers the mechanisms that play a significant role in AML cell malignant transformation and shows the contributions of certain genes to both remission and resistance of AML cells to various treatments.

[Comparative study of therapy targeted genes expression in neuroblastoma cell lines].

In this study we evaluated c-kit, VEGFA, and MYC gene expression level in seven neuroblastoma stable cell lines: SK-N-SH, SK-N-BE, SK-N-AS, SH-SY5Y, Kelly, IMR-32, and LAN-1. Expression levels of these genes can serve as diagnostic factors of cancer progression, and proteins encoded by these genes are promising targets for neuroblastoma treatment. SH-SY5Y and SK-N-AS cells have highest MYC expression and the same VEGFA expression, although SH-SY5Y has 10 times higher c-kit expression than SK-N-AS cells. Both IMR-32 and LAN-1 cells have low MYC expression level, but differ in c-kit expression, IMR-32 has significantly higher c-kit expression, than any other neuroblastoma cell line. LAN-1 on the other hand has the highest VEGFA expression. These data suggest that MYC, c-kit, and VEGFA genes can play different roles in development and progression of neuroblastoma depending on other activated molecular mechanisms in malignant cells.

[Universal modular system for in vitro screening of potential inhibitors of HIV-1 replication].

Here we describe a system based on recombinant lentiviral vectors for the safe screening of potential anti-HIV drugs. The system allows to evaluate the sensitivity of HIVl-1 reverse transcriptase and integrase (wild-type as well as mutant forms of these enzymes detected in drug-resistant virus isolates) towards different drugs and substances, but also to screen inhibitors of other stages of HIV-1 life cycle.

[Dynamics of penetration of "solid" nanoconstructions based on double-stranded DNA complexed with gadolinium into CHO cells].

Currently, neutron capture therapy is a promising cancer treatment. This method is based on the reaction of the thermal neutron capture by some non-radioactive elements (e.g., Gds57), which results in subsequent emission of electrons and gamma rays. An effective instrument for delivery of gadolinium into the tumor tissue are the particles of the "rigid" nanostructures (NS) based on double-stranded DNA complexes with gadolinium (NS-Gd). The local concentration of Gd in such nanostructures may reach 40%. To optimize the process of neutron capture therapy it is very important to investigate possible penetration mechanisms of NS-Gd particles into the tumor cells. In this work, the dynamics of interaction NS-Gd with cultivated chinese hamster ovary cells (CHO) was studied by confocal and electron microscopy. It is shown that NS-Gd are able to enter CHO cells. This process begins in about 1 hour after the start ofincubation. After 6 h NS-Gd particles were detected in almost all cells. A further increase of the incubation time does not lead to significant changes in cell morphology, although the number NS-Gd inside the cells increases. The plasma membrane of the cells remains intact. The NS-Gd particles, which entered the cells, remain inside the cells for a long time. The data obtained show that NS-Gd are relatively low-toxic and suggest that the presence of NS-Gd in the tumor cells does not prevent their division. The data obtained are important for improving the efficiency of the neutron capture therapy method.

[Expression of FLT3-ITD oncogene confers mice progenitor B-cells BAF3 sensitivity to the ribonuclease binase cytotoxic action].

Acute myeloid leukemia is the most common acute leukemia affecting adults, and its incidence increases with age. Along with chromosomal translocations in leukemic cells mutations in the genes of receptor tyrosine kinases KIT and FLT3 were found with a high frequency. Here we show that transgenic progenitor of B-cells BAF3/FLT3-ITD are much more sensitive to the ribonuclease binase cytotoxic effects than the original BAF3 cells. The principal difference between BAF3/FLT3-ITD and the original BAF3 cells is the expression of FLT3-ITD oncogene, which leads to a change in the normal cell signaling pathways. Earlier, we described a similar effect for the cytotoxic action of binase on Kasumi-1 and FDC-P1-N822K cells, which express the activated KIT-N822K oncogene. Increased binase cytotoxicity toward the cells, expressing FLT3-ITD oncogene, suggests that, as in the case of FDC-P1 cells, transduced by KIT oncogene, the expression of an activated oncogene determines the sensitivity of cells to binase.

[Downregulation of activated leukemic oncogenes AML1-ETO and RUNX1(K83N) expression with RNA-interference].

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.

[Functional state characteristics of the heart in measured coronary blood flow limitation to varying degrees]. / Osobennosti funktsional'nogo sostoianiia serdtsa pri dozirovannom ogranichenii koronarnogo krovotoka razlichnoi stepeni.

The consequences of three different degrees of restricted circulation (by 30%, 50%, and 70%) in the circumflex branch of the left coronary artery were studied in experiments on dogs in which partial strictly dosed reduction of coronary blood flow was reproduced without opening the thoracic cavity. In most cases, the first two degrees of blood flow restriction were not attended by the natural changes in the contractile function of the heart, its decrease in particular, in the first 30 minutes. In 70% restriction of blood flow, on the contrary, moderate diminution of the contractile function of the heart begins to be manifested in most of the cases despite the fact that there is no progressive deterioration in general hemodynamics.

[Modelling of measured restriction of the coronary blood flow]. / Modelirovanie dozirovannogo ogranicheniia koronarnogo krovotoka.

Experiments were conducted on dogs under conditions of closed chest catheterization and autoperfusion of the coronary vessels to study the methods and manipulations providing reliable reproduction of previously planned direct restriction of coronary blood flow, strictly dosed in degree and duration, simulating coronary insufficiency of various severity. The use of this complex of methods and manipulations makes it possible to avoid the shortcomings and undesirable consequences of denervation of the coronary arteries and their extravascular mechanical compression and the need to open the chest. The simulated restriction of coronary blood flow is reversible owing to which it may be reproduce many time in one experiment.

[Characteristics of the regulation of coronary circulation in progressive disorders of coronary perfusion]. / Osobennosti reguliatsii koronarnogo krovoobrashcheniia pri progressiruiushchikh stepeniakh narusheniia koronarnoi perfuzii.

Coronary failure was demonstrated to be followed by impaired coronary circulation regulation in the hypoperfused area, as manifested by quantitative (incomplete realization of dilator reserve) or qualitative (greater coronary resistance) alterations of coronary responses to ischemia. The disorders detected were shown to be directly related to the manifestations of limited coronary flow, predominant with its 70% decrease and represent an essential mechanism of further progression of coronary failure.

[Specific features of the regulation of coronary circulation during reperfusion after coronary insufficiency of different degrees]. / Nekotorye osobennosti reguliatsii koronarnogo krovoobrashcheniia v usloviiakh reperfuzii posle koronarnoi nedostatochnosti razlichnoi stepeni vyrazhennosti.

Coronary insufficiency of various degrees was reproduced in experiments with anesthetized dogs by using coronary artery catheterization by progressively limiting the regional blood flow by 30, 50, 70, and 90%, the dog chest being closed. The specific features of regulatory reactions of cardiac vessels were also studied under subsequent reperfusion. It was shown that regulation of coronary circulation became changed in most cases after markedly limited coronary blood flow, as manifested by impaired reperfusion hyperemia and its rapid cessation that prevented the "payment" of blood flow debt and a secondary increase of cardiac vascular resistance above the preocclusive level. There was a significant relationship between the detected disorders and the degree of prior limited coronary perfusion.

[Coronary circulation under alpha-adrenergic blockade]. / Koronarnoe krovoobrashchenie v usloviiakh al'fa-adrenergicheskoi blokady.

In canine experiments with coronary catheterization and perfusion, catheterization of the heart cavities and great vessles, and with thermodilution it was demonstrated that the alpha-adrenergic blocker Phentolamine causes a regular flow resistance in the coronary vessels. The maximal depressor effect was observed with 0.3 mg/kg (intravenously), and it did not grow under higher doses of the drug. The reduction of coronary resistance under the effect of Phentolamine was realized, firstly, by way of a moderate activation of myocardial beta-receptors, and secondly, by way of a specific block of alpha-adrenergic receptors of the heart vessels. Phentolamine inhibited the pressor reactions of the coronaries to mesatone, adrenalin, noradrenalin, and limited the manifestations of the pressor effects in the coronary vessels during systemic sinocarotid reflexes.

[Mechanism of the cardiotonic effect of alpha-adrenoblockade by phentolamine]. / O mekhenizme kardiotonicheskogo éffekta alpha-adrenoblokady fentolaminon

In canine experiments with recording intraventricular pressure and its first derivative, with electromagnetic flowmetry and thermodilution it has been demonstrated that controlled Phentolamine-induced alpha-adrenergic block results in an increase of the cardiac output, heart rate, myocardial contractility index, and, at the same time, in a reduction of the total vascular resistance, arterial pressure, intraventricular pressure and heart work. The beneficial chronotropic effect of Phentolamine was shown not to depend on its suggested "central" action, to be not determined by reflex stimulation of the cardiac activity due to systemic hypotension, but to be brought about by a block of the myocardial alpha-adrenergic receptors and a moderate activation of beta-adrenergic receptors. The concept of the untoward chronotropic effects being mediated by myocardial alpha-adrenoreceptors is being substantiated. The mechanism of the beneficial inotropic effect of Phentolamine may be based on the stimulation of beta-receptors, concomitant tachycardia, and, probably, the effect of the "centrai" action of the drug.

[Correlation between coronary dilatation reserve and cardiac contractile function after marked disorders of coronary circulation]. / Sootnoshenie mezhdu koronarnym rasshiritel'nym rezervom i sokratitel'noi funktsiei serdtsa posle vyrazhennykh narushenii koronarnogo krovoobrashcheniia.

Relationship between the realization of the coronary dilatation reserve and cardiac contractility was investigated in acute dog experiments with the intact thoracic cage under partially limited and rationed flow through a major coronary artery (a 30-minute 70% reduction), and during subsequent reperfusion. Limited coronary flow was seen in combination with moderately depressed cardiac contractility that did not improve significantly during the reperfusion period of equal duration. Inadequate realization of the coronary dilatation reserve that fails to restore the balance between blood supply and myocardial oxygen requirement may be a cause of incomplete recovery during the early reperfusion period.

[Comparative characteristics of the effect of curanthil on blood vessels of different organs]. / Sravnitel'naia kharakteristika vliianiia kurantila na sosudy raznykh organov

In experiments on dogs conducted by means of resistography Curanthil (Dipyridamol) was shown to produce a consistent fall in the resistance to the blood flow in the cardiac vessels due to their active depressor reaction. Besides, Curanthil helps a distinct fall in the resistance of the vessels of the small intestine, sceletal muscles and, to a lower degree, of the brain. These data do not support those of a selective coronary-dilating action of this drug. The reaction of the renal vessels to Curanthil was not uniform and was predominantly of a pressor nature.

[Effect of reperfusion changes of the coronary circulation on the adequacy of the myocardial blood supply]. / Vliianie reperfuzionnykh izmenenii koronarnogo krovoobrashcheniia na adekvatnost' krovosnabzheniia miokarda.

The results of reperfusion coronary circulatory alterations manifested by a rapid cessation of reactive hyperemia and a secondary increase in coronary vascular resistance were studied in acute canine experiments on a model of partial blood flow restriction by 30,, 50, 70, and 90% with subsequent reperfusion. It was shown that most frequently delayed disturbances of myocardial blood supply adequacy, which is qualified as a reperfusion coronarogenic mechanism of secondary coronary failure progression, which differs from the well-known phenomenon of unrestored coronary blood flow, which occurs after blood flow restriction to a greater extent.

Fabrication of [001]-oriented tungsten tips for high resolution scanning tunneling microscopy.

The structure of the [001]-oriented single crystalline tungsten probes sharpened in ultra-high vacuum using electron beam heating and ion sputtering has been studied using scanning and transmission electron microscopy. The electron microscopy data prove reproducible fabrication of the single-apex tips with nanoscale pyramids grained by the {011} planes at the apexes. These sharp, [001]-oriented tungsten tips have been successfully utilized in high resolution scanning tunneling microscopy imaging of HOPG(0001), SiC(001) and graphene/SiC(001) surfaces. The electron microscopy characterization performed before and after the high resolution STM experiments provides direct correlation between the tip structure and picoscale spatial resolution achieved in the experiments.

Silencing AML1-ETO gene expression leads to simultaneous activation of both pro-apoptotic and proliferation signaling.

The t(8;21)(q22;q22) rearrangement represents the most common chromosomal translocation in acute myeloid leukemia (AML). It results in a transcript encoding for the fusion protein AML1-ETO (AE) with transcription factor activity. AE is considered to be an attractive target for treating t(8;21) leukemia. However, AE expression alone is insufficient to cause transformation, and thus the potential of such therapy remains unclear. Several genes are deregulated in AML cells, including KIT that encodes a tyrosine kinase receptor. Here, we show that AML cells transduced with short hairpin RNA vector targeting AE mRNAs have a dramatic decrease in growth rate that is caused by induction of apoptosis and deregulation of the cell cycle. A reduction in KIT mRNA levels was also observed in AE-silenced cells, but silencing KIT expression reduced cell growth but did not induce apoptosis. Transcription profiling of cells that escape cell death revealed activation of a number of signaling pathways involved in cell survival and proliferation. In particular, we find that the extracellular signal-regulated kinase 2 (ERK2; also known as mitogen-activated protein kinase 1 (MAPK1)) protein could mediate activation of 23 out of 29 (79%) of these upregulated pathways and thus may be regarded as the key player in establishing the t(8;21)-positive leukemic cells resistant to AE suppression.