Reduction of myocardial infarction by calpain inhibitors A-705239 and A-705253 in isolated perfused rabbit hearts

Two novel calpain inhibitors (A-705239 and A-705253) were studied in isolated perfused rabbit hearts subjected to 60-min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid in various final concentrations from the beginning of the experiments before the coronary artery was blocked. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were carried out. Myocardial infarct size and the area at risk (transiently non-perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 77.9 +/- 2.3% of the area at risk in untreated controls (n=12). The infarct size was significantly reduced in the presence of both calpain inhibitors. The best effect was achieved with 10(-8) m A-705253 (n=8), which reduced (p<0.001) the infarcted area to 49.3 +/- 3.9% of the area at risk, corresponding to an infarct reduction of 61.8%. No statistical difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, and in the release of lactate dehydrogenase and creatine kinase from heart muscle

A melanocyte lineage program confers resistance to MAP kinase pathway inhibition

BRAFV600E-mutant malignant melanomas depend on RAF/MEK/ERK (MAPK) signaling for tumor cell growth1. RAF and MEK inhibitors show remarkable clinical efficacy in BRAFV600E melanoma2, 3; however, resistance to these agents remains a formidable challenge2, 4. Global characterization of resistance mechanisms may inform the development of more effective therapeutic combinations. Here, we performed systematic gain-of-function resistance studies by expressing >15,500 genes individually in a BRAFV600E melanoma cell line treated with RAF, MEK, ERK, or combined RAF/MEK inhibitors. These studies revealed a cyclic AMP-dependent melanocytic signaling network not previously associated with drug resistance, including G-protein coupled receptors, adenyl cyclase, protein kinase A and cAMP response element binding protein (CREB). Preliminary analysis of biopsies from BRAFV600E melanoma patients revealed that phosphorylated (active) CREB was suppressed by RAF/MEK-inhibition but restored in relapsing tumors. Expression of transcription factors activated downstream of MAP kinase and cAMP pathways also conferred resistance, including c-FOS, NR4A1, NR4A2 and MITF. Combined treatment with MAP kinase pathway and histone deacetylase inhibitors suppressed MITF expression and cAMP-mediated resistance. Collectively, these data suggest that oncogenic dysregulation of a melanocyte lineage dependency can cause resistance to RAF/MEK/ERK inhibition, which may be overcome by combining signaling- and chromatin-directed therapeutics

Комплексная оценка состояния калликреин-кининовой системы и вазодилатации у больных с ишемической болезнью сердца под влиянием терапии ингибиторами ангиотензинпревращающего фермента

Представлены результаты обследования больных крупноочаговым инфарктом миокарда, больных стабильной стенокардией, больных нестабильной стенокардией и больных ишемической болезнью сердца, осложненной недостаточностью кровообращени

The alpha-synuclein 5'untranslated region targeted translation blockers: anti-alpha synuclein efficacy of cardiac glycosides and Posiphen

Increased brain α-synuclein (SNCA) protein expression resulting from gene duplication and triplication can cause a familial form of Parkinson's disease (PD). Dopaminergic neurons exhibit elevated iron levels that can accelerate toxic SNCA fibril formation. Examinations of human post mortem brain have shown that while mRNA levels for SNCA in PD have been shown to be either unchanged or decreased with respect to healthy controls, higher levels of insoluble protein occurs during PD progression. We show evidence that SNCA can be regulated via the 5'untranslated region (5'UTR) of its transcript, which we modeled to fold into a unique RNA stem loop with a CAGUGN apical loop similar to that encoded in the canonical iron-responsive element (IRE) of L- and H-ferritin mRNAs. The SNCA IRE-like stem loop spans the two exons that encode its 5'UTR, whereas, by contrast, the H-ferritin 5'UTR is encoded by a single first exon. We screened a library of 720 natural products (NPs) for their capacity to inhibit SNCA 5'UTR driven luciferase expression. This screen identified several classes of NPs, including the plant cardiac glycosides, mycophenolic acid (an immunosuppressant and Fe chelator), and, additionally, posiphen was identified to repress SNCA 5'UTR conferred translation. Western blotting confirmed that Posiphen and the cardiac glycoside, strophanthidine, selectively blocked SNCA expression (~1 μM IC(50)) in neural cells. For Posiphen this inhibition was accelerated in the presence of iron, thus providing a known APP-directed lead with potential for use as a SNCA blocker for PD therapy. These are candidate drugs with the potential to limit toxic SNCA expression in the brains of PD patients and animal models in vivo

Update on safety during pregnancy of biological agents and some immunosuppressive anti-rheumatic drugs

A consensus paper concerning the interaction of anti-rheumatic drugs and reproduction was published in 2006, representing data collected during the year 2004 and 2005. Because of an increasing use of biological agents in women of fertile age, the information was updated for the years 2006 and 2007. Experts disagree whether TNF-inhibitors should be stopped as soon as pregnancy is recognized or may be continued throughout pregnancy. Pregnancy experience with abatacept and rituximab is still too limited to prove their safety for the developing fetus. They must be withdrawn before a planned pregnancy. LEF has not been proven to be a human teratogen. Registries of transplant recipients have shown that cyclosporin (CsA) and tacrolimus do not increase the rate of congenital anomalies, whereas mycophenolate mofetil (MMF) clearly carries a risk for congenital anomalies. Prophylactic withdrawal of drugs before pregnancy is mandatory for abatacept, rituximab, LEF and MMF. Data remain insufficient for gonadal toxicity of immunosuppressive drugs in men and for excretion of these drugs in human breast mil

Targeting nuclear transporters in cancer: Diagnostic, prognostic and therapeutic potential

The Karyopherin superfamily is a major class of soluble transport receptors consisting of both import and export proteins. The trafficking of proteins involved in transcription, cell signalling and cell cycle regulation among other functions across the nuclear membrane is essential for normal cellular functioning. However, in cancer cells, the altered expression or localization of nuclear transporters as well as the disruption of endogenous nuclear transport inhibitors are some ways in which the Karyopherin proteins are dysregulated. The value of nuclear transporters in the diagnosis, prognosis and treatment of cancer is currently being elucidated with recent studies highlighting their potential as biomarkers and therapeutic targets

Rotenone selectively occludes sensitivity to hypoxia in rat carotid body glomus cells

Carotid body glomus cells release transmitters in response to hypoxia due to the increase of excitability resulting from inhibition of O2 -regulated K+ channels. However, the mechanisms involved in the detection of changes of O2 tension are unknown. We have studied the interaction between glomus cell O2 sensitivity and inhibition of the mitochondrial electron transport chain (ETC) in a carotid body thin slice preparation in which catecholamine release from intact single glomus cells can be monitored by amperometry. Inhibition of the mitochondrial ETC at proximal and distal complexes induces external Ca2+-dependent catecholamine secretion. At saturating concentration of the ETC inhibitors, the cellular response to hypoxia is maintained. However, rotenone, a complex I blocker, selectively occludes the responsiveness to hypoxia of glomus cells in a dose-dependent manner. The effect of rotenone is mimicked by 1-methyl-4-phenylpyridinium ion(MPP+), an agent that binds to the same site as rotenone, but not by complex I inhibitors acting on different sites. In addition, the effect of rotenone is not prevented by incubation of the cells with succinate, a substrate of complex II. These data strongly suggest that sensitivity to hypoxia of carotid body glomus cells is not linked in a simple way to mitochondrial electron flow and that a rotenone (and MPP+)-sensitive molecule critically participates in acute oxygen sensing in the carotid body.Ministerio de Ciencia y Tecnología 1FD97–161

<i>N,N</i>-bis-(dimethylfluorosilylmethyl)amides of <i>N</i>-organosulfonylproline and sarcosine: synthesis, structure, stereodynamic behaviour and <i>in silico</i> studies

(O→Si)-Chelate difluorides R3R2NCH(R1)C(O)N(CH2SiMe2F)2 (9a–c, R1R2 = (CH2)3, R3 = Ms (a), Ts (b); R1 = H, R2 = Me, R3 = Ms (c)), containing one penta- and one tetracoordinate silicon atoms were synthesized by silylmethylation of amides R3R2NCH(R1)C(O)NH2, subsequent hydrolysis of unstable intermediates R3R2NCH(R1)C(O)N(CH2SiMe2Cl)2 (7a–c) into 4-acyl-2,6-disilamorpholines R3R2NCH(R1)C(O)N(CH2SiMe2O)2 (8a–c) and the reaction of the latter compounds with BF3·Et2O. The structures of disilamorpholines 8a,c and difluoride 9a were confirmed by an X-ray diffraction study. According to the IR and NMR data, the O→Si coordination in solutions of these compounds was weaker than that in the solid state due to effective solvation of the Si–F bond. A permutational isomerisation involving an exchange of equatorial Me groups at the pentacoordinate Si atom in complexes 9a–c was detected, and its activational parameters were determined by 1H DNMR. In silico estimation of possible pharmacological effects and acute rat toxicity by PASS Online and GUSAR Online services showed a potential for their further pharmacological study

Chloramidine/Bisindolylmaleimide-I-Mediated Inhibition of Exosome and Microvesicle Release and Enhanced Efficacy of Cancer Chemotherapy

Microvesicle (MV) release from tumour cells influences drug retention, contributing to cancer drug resistance. Strategically regulating MV release may increase drug retention within cancer cells and allow for lower doses of chemotherapeutic drugs. The contribution of exosomes to drug retention still remains unknown. Potential exosome and MV (EMV) biogenesis inhibitors, tested on human prostate cancer (PC3) cells for their capacity to inhibit EMV release, were also tested on PC3 and MCF-7 (breast cancer) cells for improving chemotherapy. Agents inhibiting EMV release most significantly, whilst maintaining cell viability, were chloramidine (Cl-amidine; 50 µM) and bisindolylmaleimide-I (10 µM). Apoptosis mediated by the chemotherapy drug 5-fluorouracil (5-FU) was significantly enhanced in PC3 cells in the presence of both these EMV inhibitors, resulting in a 62% (Cl-amidine + 5-FU) and 59% (bisindolylmaleimide-I + 5-FU) decrease in numbers of viable PC3 cells compared to 5-FU alone after 24 h. For MCF-7 cells, there were similar increased reductions of viable cells compared to 5-FU treatment alone ranging from 67% (Cl-amidine + 5-FU) to 58% (bisindolylmaleimide-I + 5-FU). Using combinatory treatment, the two EMV inhibitors further reduced the number of viable cancer cells tested. Neither inhibitor affected cell viability. Combining selected EMV inhibitors may pose as a novel strategy to enhance the efficacy of chemotherapeutic drug-mediated apoptosis