[Influence of N-alkynylaminosteroids on mitochondria function and autophagy in glioma cells]. / Vliianie N-alkinilaminosteroidov na funktsionirovanie mitokhondrii i protsessy autofagii v kletkakh gliomy.

In this work we examined the synthesized N-alkynyl-17-aminosteroids and N-alkynyl-20-aminosteroids (based on dehydroepiandrosterone and pregnenolone, respectively) for their effect on C6 rat glioma cell functions. At 10 µM, the compounds had an insignificant effect on C6 glioma mitochondrial membrane potential, but increased cell autophagy by 70-90%, comparable to the known autophagy inducer dexamethasone. Docking simulations predict a potential high-affinity interaction between N-alkynylaminosteroids and Keap1 and the Hedgehog pathway protein, Smoothened, which are involved in autophagy regulation. The possible mechanisms of observed processes are discussed.

[Glycoprotein IIb-IIIa antagonist Monafram in primary angioplasty of patients with acute coronary syndrome without st segment elevation].

Glycoprotein (GP) llb-llla anagonist monafram is the F(ab)2 fragments of anti GP llb llla monoclonal antibody FraMon (CRC64). Efficacy and safety of monafram in primary coronary angioplasty of patients with acute coronary syndrome without ST segment elevation (non ST ACS) was evaluated in this study. Monafram was introduced intravenously to 284 patients just before angioplasty at standard dosage - 0.25 mg/kg as single i.v. bolus. Control group included 203 patients. All patients received aspirin (loading dose 300 mg and then 75 mg daily) and more than 90% - clopidogrel (loading dose 300-600 mg and then 75 mg daily). Within 30 days of follow up period monafram decreased by more than 2.5 fold the total amount of unfavorable outcomes (cardiovascular death, myocardial infarction and indications for repeat revascularization due to angina recurrence) - from 19.2% to 7.4% (p<0.001). The rate of indications for revascularization was most strongly decreased - by more than 7 times - from 7.9% to 1.1% (p<0.001). The number of myocardial infarctions was reduced by more than 2 times - from 8.4% to 3.9% (p=0.057). The amount of lethal outcomes did not differ between two groups (2.9% and 2.4% in the control and monafram groups, respectively). In the control group 8.9% patients received monafram during primary angioplasty due to urgent indications. Monafram did not cause any allergic reaction in all tested patients. Major bleeding was registered in one (less than 0.5%) and deep thrombocytopenia (<20000 platelets per 1 ul) - in 3 (1.1%) out of 284 patients. The data obtained indicated that monafram decreased the number of thrombotic complications in non ST ACS patients undergoing angioplasty upon the dual antiplatelet therapy (aspirin+clopidogrel) and without significant increase of dangerous side effects.

[Clopidogrel resistance in patients with acute coronary syndrome].

AIM: to reveal the frequency of clopidogrel resistance in patients with acute coronary syndrome (ACS) and its impact on prognosis in these patients. SUBJECTS AND METHODS: Seventy-five clopidogrel-treated patients with ACS were followed up. Optical aggregometry was conducted using ADP 20 micromol. The resistance criteria were baseline platelet aggregation, platelet aggregation on day 7, % < 10%. Inflammatory markers (IL-6, IL-10, and C-reactive protein) were determined. Genetic polymorphisms (the IIIa subunit gene--Leu33Pro, the receptor P2Y(12) C18T and G36T gene, and the CYP3*A4(A-293G) gene) were studied. RESULTS: According to the accepted resistance criteria, 54 (72%) patients were sensitive to clopidogrel and 21 (28%) were resistant to the agent. The resistance was revealed in 7 (23%) of the patients with ECG ST-segment elevation and in 14 (31%) of those with ST-segment elevation. Before admission to the clinic, the unresponsive patients had significantly more frequently received the loading clopidogrel dose of 300 mg while that latter was 600 mg in the responsive patients. As compared with the responsive patients, the unresponsive ones showed a significantly lower baseline antibody level that was increased on day 7. The clopidogrel resistance determined by this criterion had no impact on prognosis. On dividing the patients by aggregation quartile values, poor manifestations insignificantly more frequently occurred in the third and fourth quartiles. No clear correlation was found between the occurrence of clopidogrel resistance and the activation of an inflammatory process. The monozygous variant of the receptor P2Y(12) CT18T gene was insignificantly more frequently encountered in the unresponsive patients. CONCLUSION: The laboratory phenomenon of clopidogrel resistance exists. Large multicenter studies of this issue are needed to identify simple and least expensive resistance methods and clear diagnostic criteria that enable the findings to be compared.

[In silico modeling of izoniazid-steroid conjugates interactions with cytochromes P450 of mycobacteria and their bioconversion in vitro by the cells]. / In silico modelirovanie vzaimodeistviia kon"iugatov izoniazid-steroid s tsitokhromami P450 mikobakterii i ikh prevrashchenie in vitro v kletkakh dannykh mikroorganizmov.

Molecular docking of four hydrazones of isoniazid with steroids (dehydroepiandrosterone, pregnenolone, 16α,17α-epoxypregnenolone, cholestenone) - IDHEA, IPRE, IEP5, ICHN, to mycobacterial cytochromes P450 was performed. The in silico study has shown than these hydrazones can be effectively bound to CYP121, CYP124, CYP125, CYP126A1, CYP130, and CYP51 with binding energy ranged from -9 kcal/mol to -12 kcal/mol. Calculations also demonstrated enhancement of passive lipid bilayer permeability with respect to isoniazid. In vitro IDHEA, IPRE, IEPR were found to undergo bioconversion into their 3-keto-4-en derivatives. This suggests their ability to penetrate into M. tuberculosis H37Rv cells. The results of this study are important in the context of understanding of specificity of binding of synthetic steroid derivatives to mycobacterial CYPs and indicate the possibility of using the steroid compounds studied by us as new ligands for these enzymes.

[Synthesis and evaluation of N-alkynylaminosteroids as potential CYP450 17A1 inhibitors]. / N-alkinilaminosteroidy v kachestve potentsial'nykh ingibitorov tsitokhroma P450 17A1.

Four isomeric dehydroepiandrosterone- and pregnenolone-based N-alkynylaminosteroids were synthesized and tested in vitro for inhibition of heterologously expressed CYP17A1. The highest inhibitory activity was observed when the optimal number of side chain atoms was met. The conjugate based on pregnenolone containing an N-propynyl moiety was found to interefere with enzymatic activity most effectively and consistently in the micromolar range.

[Range of substrates and steroid bioconversion reactions performed by recombinant microorganisms Saccharomyces cerevisiae and Yarrowia lipolytica expressing cytochrome P450c17].

The relationship between 17alpha-hydroxylation and 20-oxidation-reduction of progesterone and some of its derivatives was studied in yeast strains Saccharomyces cerevisiae YEp51alpha, Yarrowia lipolytica E129A15, and expressing cytochrome P450c17. The key metabolites were found to be 17alpha-hydroxyprogesterone and 17alpha,20(alpha,beta)-dihydroxypregn-4-ene-3-ones. The bioconversion pathways of pregn-4-ene-20(alpha,beta)-ol-3-ones were determined. They included cycles of 20-oxidation, 17alpha-hydroxylation, and stereospecific 20-reduction. The efficiency and kinetic parameters of steroid bioconversion by the recombinant strains were determined. The role of yeast analogs of mammalian steroid dehydrogenases is discussed. It was found that any of the desired derivatives, 17alpha-hydroxyprogesterone or progesterone 17alpha,20(alpha,beta)-diols, could be obtained from progesterone.

[Effect of steroid biosynthesis modificators on the progesterone biotransformation by a recombinant yeasts expressing cytochrome P450c17].

Using the recombinant microorganisms S. cerevisiae GRF18 YEp5117alpha, expressing cytochrome P450c17 from bovine adrenal cortex, we investigated the influence of the various modificators of steroids biosynthesis on the relationship between the 17alpha-hydroxylation of progesterone and 20alpha-reduction. Dexamethasone and metirapon had no effect on the reaction of progesterone 17alpha-hydroxylation and on the reaction of 17alpha-hydroxyprogesterone 20alpha-reduction. Mifepriston and danazol did not covalently modify amino acid residues of the cytochrome P450c17 or its heme group under the conditions of the biotransformation of progesterone by recombinant yeasts. Ketokonazol, mifepriston and danazol acted as low-affinity competitive inhibitors, but the 20-dihydro derivatives of progesterone were mixed type inhibitors for the cytochrome P450c17. All modifiers that we used did not influence the functional properties of the yeast analog of 20alpha-hydroxysteroid dehydrogenase. According to the influence on the catalytic parameters of the cytochrome P450c17, the modifiers used can be arranged in the following order: 20beta-dihydroprogesterone (maximum effect) > mifepriston = ketokonazol > 20alpha-dihydroprogesteron > danazol > dexamethasone, metirapon (without effect).

Prion properties of the Sup35 protein of yeast Pichia methanolica.

The Sup35 protein (Sup35p) of Saccharomyces cerevisiae is a translation termination factor of the eRF3 family. The proteins of this family possess a conservative C-terminal domain responsible for translation termination and N-terminal extensions of different structure. The N-terminal domain of Sup35p defines its ability to undergo a heritable prion-like conformational switch, which is manifested as the cytoplasmically inherited [PSI(+)] determinant. Here, we replaced the N-terminal domain of S.cerevisiae Sup35p with an analogous domain from Pichia methanolica. Overexpression of hybrid Sup35p induced the de novo appearance of cytoplasmically inherited suppressor determinants manifesting key genetic and biochemical traits of [PSI(+)]. In contrast to the conventional [PSI(+)], 'hybrid' [PSI(+)] showed lower mitotic stability and preserved their suppressor phenotype upon overexpression of the Hsp104 chaperone protein. The lack of Hsp104 eliminated both types of [PSI(+)]. No transfer of prion state between the two Sup35p variants was observed, which reveals a 'species barrier' for the [PSI(+)] prions. The data obtained show that prion properties are conserved within at least a part of this protein family.

Biotransformation of steroids by a recombinant yeast strain expressing bovine cytochrome P-45017alpha.

The cDNA encoding cytochrome P-45017alpha from bovine adrenal cortex was expressed in Saccharomyces cerevisiae under the control of the galactose-inducible GAL10 promoter. Carbon monoxide difference spectra of the galactose-induced yeast cells showed expression of about 240 nmol of P-45017alpha per liter of the culture. Binding of progesterone to the cytochrome P-45017alpha was clearly detectable already with intact yeast cells as judged by the formation of type I substrate difference spectra. Yeast cells grown on minimal medium containing galactose actively converted progesterone to 17alpha-hydroxyprogesterone, this indicating the functional integrity of the heterologously expressed P-45017alpha and its efficient coupling with the constitutive NADPH-cytochrome P-450 reductase. More than 80% of the metabolite produced was secreted into the culture medium. Cultivation in a rich non-selective medium resulted in the formation of an additional product, which was identified by mass spectrometry as 17alpha-hydroxy-20-dihydroprogesterone. Kinetic analysis revealed that its production followed the cytochrome P-45017alpha-dependent hydroxylation reaction. The reduction of the 20-keto group of 17alpha-hydroxyprogesterone was also observed in the non-induced yeast culture, this suggesting the involvement of the constitutive enzyme. Among several substrates tested, progesterone was hydroxylated by the cytochrome P-45017alpha expressed with the highest activity. The activity towards other substrates decreased in the sequence: 11beta- > 11alpha- > 19-hydroxyprogesterone. In conclusion, the present results show that the host-vector system used is suitable for high-level functional expression of P-45017alpha and further application of enzymatic properties of this protein to perform specific steroid biotransformations.