Inhibition of mitochondrial translation as a therapeutic strategy for human acute myeloid leukemia

To identify FDA-approved agents targeting leukemic cells, we performed a chemical screen on two human leukemic cell lines and identified the antimicrobial tigecycline. A genome-wide screen in yeast identified mitochondrial translation inhibition as the mechanism of tigecycline-mediated lethality. Tigecycline selectively killed leukemia stem and progenitor cells compared to their normal counterparts and also showed antileukemic activity in mouse models of human leukemia. ShRNA-mediated knockdown of EF-Tu mitochondrial translation factor in leukemic cells reproduced the antileukemia activity of tigecycline. These effects were derivative of mitochondrial biogenesis that, together with an increased basal oxygen consumption, proved to be enhanced in AML versus normal hematopoietic cells and were also important for their difference in tigecycline sensitivity.     

Fenofibrate attenuates contact-stimulated cell motility and gap junctional coupling in DU-145 human prostate cancer cell populations

In the present study, we investigated the effects of fenofibrate on the invasive potential of DU-145 human prostate cancer cells in the context of gap junctional intercellular coupling and the formation of reactive oxygen species. Time-lapse analyses of cell motility, accompanied by tests of cell viability, membrane microviscosity, reactive oxygen species accumulation and the function of gap junctional protein connexin 43 were performed in monolayer cultures of DU-145 cells following fenofibrate administration. Fenofibrate inhibited the motility of DU-145 cells and attenuated gap junctional intercellular coupling in a manner independent of its effects on cell viability, PPARα activation and cell membrane micro-viscosity. Instead, N-acetyl-L-cysteine, a scavenger of reactive oxygen species, restored cell motility and gap junctional coupling in fenofibrate-treated DU-145 cell populations. These data indicate that two parameters crucial for cancer cell metastatic potential, i.e. cell motility and gap junctional coupling, are inhibited by fenofibrate. Thus, fenofibrate affects prostate cancer cell invasion via an orchestrated action on versatile cancer cell properties determining this process. A novel mechanism of anti-invasive activity of fenofibrate, which depends on its interference with cell motility and the function of gap junctions regulated by reactive oxygen species, is suggested.     

Directed epitope delivery across the Escherichia coli outer membrane through the porin OmpF

The porins OmpF and OmpC are trimeric β-barrel proteins with narrow channels running through each monomer that exclude molecules > 600 Da while mediating the passive diffusion of small nutrients and metabolites across the Gram-negative outer membrane (OM). Here, we elucidate the mechanism by which an entire soluble protein domain (> 6 kDa) is delivered through the lumen of such porins. Following high-affinity binding to the vitamin B(12) receptor in Escherichia coli, the bacteriocin ColE9 recruits OmpF or OmpC using an 83-residue intrinsically unstructured translocation domain (IUTD) to deliver a 16-residue TolB-binding epitope (TBE) in the center of the IUTD to the periplasm where it triggers toxin entry. We demonstrate that the IUTD houses two OmpF-binding sites, OBS1 (residues 2-18) and OBS2 (residues 54-63), which flank the TBE and bind with K(d)s of 2 and 24 μM, respectively, at pH 6.5 and 25 oC. We show the two OBSs share the same binding site on OmpF and that the colicin must house at least one of them for antibiotic activity. Finally, we report the structure of the OmpF-OBS1 complex that shows the colicin bound within the porin lumen spanning the membrane bilayer. Our study explains how colicins exploit porins to deliver epitope signals to the bacterial periplasm and, more broadly, how the inherent flexibility and narrow cross-sectional area of an IUP domain can endow it with the ability to traverse a biological membrane via the constricted lumen of a β-barrel membrane protein.     

Teat tablet with sodium ibuprofen: the effect of sorbitol on therapeutic agent pharmaceutical availability and on physicochemical parameters of a drug form

Dosing pediatric drugs available on pharmaceutical markets of analgesic, antifebrile and anti-inflammatory activity to children up to 3 years of age is not precise and frequently causes problems. The aim of the study was to work out a pediatric teat form of a drug with sodium ibuprofen and to determine the effect of sorbitol content on pharmaceutical availability of the therapeutic agent. Three variants of tablets containing 50 mg of sodium ibuprofen differing in the percentage content of sorbitol (from 37% - batch I to 79% - batch III) were produced. Quality tests of the produced forms of drugs (PPVI) were performed and the tests of therapeutic agent pharmaceutical availability by spatula method and by a method with a teat. Tablets of all batches had a smooth surface and same shape. The content of the therapeutic agent was within the limit of 95-105% of the declared value. The highest value of Q coefficient in the release test by pharmacopeal method and the shortest disintegration time (12 minutes) were obtained for tablets with 79% content of sorbitol. In conclusion, teat tablets with sodium ibuprofen of the highest sorbitol content (79%) demonstrated the expected physicochemical parameters and high pharmaceutical availability.     

Changes in characteristics of patients with hepatitis C virus-related cirrhosis from the beginning of the interferon-free era

BACKGROUND Nearly 290000 patients with chronic hepatitis C die annually from the most severe complications of the disease. One of them is liver cirrhosis, which occurs in about 20% of patients chronically infected with the hepatitis C virus(HCV). Direct-acting antivirals(DAAs), which replaced interferon(IFN)-based regimens, significantly improved the prognosis of this group of patients,increasing HCV eradication rates and tolerability of therapy. Our study is the first to assess changes in patie...     

Genetics of Lesch's typology of alcoholism

It is widely accepted that dopamine and serotonin (5-HT) neurotransmission can be critically involved in the development of alcohol abuse and alcohol dependence. Lesch's typology of alcoholism has been gaining increasing popularity as it qualitatively differentiates patients into different treatment response subgroups. The aim of the present study was to evaluate a possible genetic background of Lesch's typology with special emphasis placed on dopamine- and serotonin-related genes. 122 alcoholics (the mean age: 35+/-9 years) were investigated. According to Lesch's typology, 58 patients were of type I, 36 patients of type II, 11 patients of type III, and 17 patients of type IV. Alcohol drinking and family history was assessed by means of a structured interview, based on the Semi-Structured Assessment for the Genetics of Alcoholism. 150 control subjects without psychiatric disorders were also recruited. The control group was ethnically-, age- and gender-matched to the patients. The DRD2 TaqIA, exon 8, and promoter -141C ins/del polymorphisms as well as COMT Val158Met, 5HTT 44 bp del in promoter, and DAT 40 bp VNTR polymorphisms were detected by means of PCR. No significant differences were observed when the whole group of alcoholics and the controls were compared. Similarly, there were no differences between either the Lesch type I or type II alcoholics and the control subjects. No significant differences were observed between type I and type II alcoholics. Alleles frequencies were not calculated for the Lesch type III and type IV alcoholics since the number of patients was too small. The present results argue against any major role of the investigated polymorphisms in either Lesch type I or type II alcoholism. More comprehensive studies are needed to define the role of the investigated polymorphisms in Lesch type III and type IV alcoholism.     

Increased number of circulating endothelial cells (CECs) in patients with psoriasis ‐ preliminary report

Background Numerous studies have demonstrated increased cardiovascular risk in psoriasis. Circulating endothelial cells (CECs) have been proposed as a new marker of endothelial dysfunction that plays an important role in pathogenesis of atherosclerosis. Objective The aim of this study was to compare the number of CECs in psoriatic patients to a control group and to analyze possible correlations between the numbers of CECs and the plasma levels of classical markers of endothelial dysfunction, such as: sICAM‐1, sE‐selectin and von Willebrand factor (vWF). Methods The number of CECs, identified as CD146 + / CD45‐ cells, were determined in peripheral blood with using flow cytometry in psoriatic patients (n = 63) and controls (n = 31). The plasma levels of: sICAM‐1, sE‐selectin, vWF were measured with ELISA. The severity of psoriasis was assessed with PASI. Results The number of CECs was significantly increased in psoriatic patients compared with controls (P < 0.00001) and positively correlated with disease severity (R = 0.360; P = 0.0037). The levels of sICAM‐1, sE‐selectin and vWF were significantly elevated in psoriatic patients (P < 0.00001; P < 0.00001; P = 0.00072, respectively). The number of CECs was significantly, positively correlated with the levels of sICAM‐1 (R = 0.393; P = 0.0014) and vWF (R = 0.314; P = 0.012) in psoriatic patients. The levels of sICAM‐1 and sE‐selectin were positively correlated with disease severity (R = 0.356; P = 0.0041 and R = 0.407; P = 0.0009, respectively). Conclusion The increased number of CECs that correlates with disease severity and plasma levels of sICAM‐1 and vWF may indicate endothelial dysfunction or injury in patients with psoriasis.