The Discovery of Novel 10,11-Dihydro-5H-dibenz[b,f]azepine SIRT2 Inhibitors.

Isoform selective inhibitors of the sirtuins (NAD-dependent histone deacetylases) should enable an in depth study of the molecular biology underpinning these targets and how they are deregulated in diseases such as cancer and neurodegeneration. Herein, we present the discovery of structurally novel SIRT2 inhibitors. Hit molecule was discovered through the chemical synthesis and biological characterization of a small-molecule compound library based around the 10,11-dihydro-5H-dibenz[b,f]azepine scaffold.

Duckweed rising at Chengdu: summary of the 1st International Conference on Duckweed Application and Research.

Duckweeds, plants of the Lemnaceae family, have the distinction of being the smallest angiosperms in the world with the fastest doubling time. Together with its naturally ability to thrive on abundant anthropogenic wastewater, these plants hold tremendous potential to helping solve critical water, climate and fuel issues facing our planet this century. With the conviction that rapid deployment and optimization of the duckweed platform for biomass production will depend on close integration between basic and applied research of these aquatic plants, the first International Conference on Duckweed Research and Applications (ICDRA) was organized and took place in Chengdu, China, from October 7th to 10th of 2011.

Phosphorylation of FOXO3a on Ser-7 by p38 promotes its nuclear localization in response to doxorubicin.

FOXO3a is a forkhead transcription factor that regulates a multitude of important cellular processes, including proliferation, apoptosis, differentiation, and metabolism. Doxorubicin treatment of MCF-7 breast carcinoma cells results in FOXO3a nuclear relocation and the induction of the stress-activated kinase p38 MAPK. Here, we studied the potential regulation of FOXO3a by p38 in response to doxorubicin.

Sheathing the swords of death: post-translational modulation of plant metacaspases.

Plant metacaspases (MCPs) are conserved cysteine proteases that have been postulated as regulators of programmed cell death (PCD). Although MCPs have been proven to have PCD relevant functions in multiple species ranging from fungi to plants, how these proteases are modulated in vivo remains unclear. Aside from demonstrating that these proteases are distinct from metazoan caspases due to their different target site specificities, how these proteases are used to tightly regulate cell death progression is a key question that remains to be resolved.

Mechanisms of endometrial progesterone resistance.

Throughout the reproductive years, the rise and fall in ovarian hormones elicit in the endometrium waves of cell proliferation, differentiation, recruitment of inflammatory cells, apoptosis, tissue breakdown and regeneration. The activated progesterone receptor, a member of the superfamily of ligand-dependent transcription factors, is the master regulator of this intense tissue remodelling process in the uterus. Its activity is tightly regulated by interaction with cell-specific transcription factors and coregulators as well as by specific posttranslational modifications that respond dynamically to a variety of environmental and inflammatory signals.

Retrospective analysis of radiation exposure during endoscopic retrograde cholagiopancreatography: critical determinants.

Background: Fluoroscopy during endoscopic retrograde cholangiopancreatography (ERCP) has a logarithmic relationship with radiation exposure, and carries a known risk of radiation exposure to patients and staff. Factors associated with prolonged fluoroscopy duration have not been well delineated.

Objectives: To determine the specific patient, physician and procedural factors that affect fluoroscopy duration.

FOXM1: From cancer initiation to progression and treatment.

The Forkhead box protein M1 (FOXM1) transcription factor is a regulator of myriad biological processes, including cell proliferation, cell cycle progression, cell differentiation, DNA damage repair, tissue homeostasis, angiogenesis and apoptosis. Elevated FOXM1 expression is found in cancers of the liver, prostate, brain, breast, lung, colon, pancreas, skin, cervix, ovary, mouth, blood and nervous system, suggesting it has an integral role in tumorigenesis. Recent research findings also place FOXM1 at the centre of cancer progression and drug sensitivity.

iASPP and chemoresistance in ovarian cancers: effects on paclitaxel-mediated mitotic catastrophe.

Purpose: iASPP is a specific regulator of p53-mediated apoptosis. Herein, we provided the first report on the expression profile of iASPP in ovarian epithelial tumor and its effect on paclitaxel chemosensitivity.

Experimental Design: Expression and amplification status of iASPP was examined in 203 clinical samples and 17 cell lines using immunohistochemistry, quantitative real-time PCR, and immunoblotting, and correlated with clinicopathologic parameters.

ERβ1 represses FOXM1 expression through targeting ERα to control cell proliferation in breast cancer.

In this study, we investigated the effects of ectopic estrogen receptor (ER)β1 expression in breast cancer cell lines and nude mice xenografts and observed that ERβ1 expression suppresses tumor growth and represses FOXM1 mRNA and protein expression in ERα-positive but not ERα-negative breast cancer cells. Furthermore, a significant inverse correlation exists between ERβ1 and FOXM1 expression at both protein and mRNA transcript levels in ERα-positive breast cancer patient samples. Ectopic ERβ1 expression resulted in decreased FOXM1 protein and mRNA expression only in ERα-positive but not ERα-negative breast carcinoma cell lines, suggesting that ERβ1 represses ERα-dependent FOXM1 transcription.

Rapid temporal control of Foxp3 protein degradation by sirtuin-1.

Maintenance of Foxp3 protein expression in regulatory T cells (Treg) is crucial for a balanced immune response. We have previously demonstrated that Foxp3 protein stability can be regulated through acetylation, however the specific mechanisms underlying this observation remain unclear. Here we demonstrate that SIRT1 a member of the lysine deacetylase Sirtuin (SIRT) family, but not the related SIRTs 2-7, co-localize with Foxp3 in the nucleus.

ATM and p53 regulate FOXM1 expression via E2F in breast cancer epirubicin treatment and resistance.

In this report, we investigated the role and regulation of forkhead box M1 (FOXM1) in breast cancer and epirubicin resistance. We generated epirubicin-resistant MCF-7 breast carcinoma (MCF-7-EPI(R)) cells and found FOXM1 protein levels to be higher in MCF-7-EPI(R) than in MCF-7 cells and that FOXM1 expression is downregulated by epirubicin in MCF-7 but not in MCF-7-EPI(R) cells. We also established that there is a loss of p53 function in MCF-7-EPI(R) cells and that epirubicin represses FOXM1 expression at transcription and gene promoter levels through activation of p53 and repression of E2F activity in MCF-7 cells.

FOXO transcription factors and their role in disorders of the female reproductive tract.

All fundamental reproductive events in the human ovary and uterus, including ovulation, implantation and menstruation, are dependent upon profound tissue remodelling, characterized by cyclical waves of cell proliferation, differentiation, recruitment of inflammatory cells, apoptosis, tissue breakdown and regeneration. Although the rise and fall in ovarian hormones, estradiol and progesterone, orchestrate these reproductive events, FOXO transcription factors, an evolutionary conserved subfamily of forkhead transcription factors, have emerged major downstream effector molecules, capable of integrating hormonal cues with a variety of stress, growth factor and cytokine signal transduction pathways. The ability of FOXOs to regulate seemingly opposing cellular responses, ranging from cell cycle arrest and oxidative stress responses to differentiation and apoptosis, renders these transcription factors indispensable for cyclic tissue remodelling in the reproductive tract.

FOXO and FOXM1 in cancer: the FOXO-FOXM1 axis shapes the outcome of cancer chemotherapy.

FOXO transcription factors, functioning downstream of the PI3K-PTEN-AKT (PKB) signalling cascade, are essential for cell proliferation, differentiation, DNA damage repair, and apoptosis. Recent research indicates that the related transcription factor FOXM1 is a direct target of repression by FOXO proteins. Inactivation of FOXO or overexpression of FOXM1 is associated with tumorigenesis and cancer progression.

Arabidopsis metacaspase 2d is a positive mediator of cell death induced during biotic and abiotic stresses.

Cysteine proteases such as caspases play important roles in programmed cell death (PCD) of metazoans. Plant metacaspases (MCPs), a family of cysteine proteases structurally related to caspases, have been hypothesized to be ancestors of metazoan caspases, despite their different substrate specificity. Arabidopsis thaliana contains six type II MCP genes (AtMCP2a-f).

The diversity of sex steroid action: the role of micro-RNAs and FOXO transcription factors in cycling endometrium and cancer.

The rise and fall in ovarian oestrogen and progesterone production orchestrates a series of events that are indispensable for reproduction, including ovulation, implantation, decidualisation and menstruation. In the uterus, these events involve extensive tissue remodelling, characterised by waves of endometrial cell proliferation, differentiation, recruitment of inflammatory cells, apoptosis, tissue breakdown, menstruation and regeneration. The ability of ovarian hormones to trigger such diverse physiological responses is foremost dependent upon interaction of activated steroid receptors with specific transcription factors, such as Forkhead box class O (FOXO) proteins, involved in cell fate decisions.

FLIM FRET technology for drug discovery: automated multiwell-plate high-content analysis, multiplexed readouts and application in situ.

A fluorescence lifetime imaging (FLIM) technology platform intended to read out changes in Förster resonance energy transfer (FRET) efficiency is presented for the study of protein interactions across the drug-discovery pipeline. FLIM provides a robust, inherently ratiometric imaging modality for drug discovery that could allow the same sensor constructs to be translated from automated cell-based assays through small transparent organisms such as zebrafish to mammals. To this end, an automated FLIM multiwell-plate reader is described for high content analysis of fixed and live cells, tomographic FLIM in zebrafish and FLIM FRET of live cells via confocal endomicroscopy.

Calcium-dependent activation and autolysis of Arabidopsis metacaspase 2d.

Metacaspases (MCPs) are members of a new family of cysteine proteases found in plants, fungi, and protozoa that are structurally related to metazoan caspases. Recent studies showed that plant MCPs are arginine/lysine-specific cysteine proteases with caspase-like processing activities in vitro and in vivo, and some of the plant type II MCPs exhibit Ca(2+) dependence for their endopeptidase activity in vitro. However, the mechanisms and biological relevance of Ca(2+) dependence and self-processing of plant MCPs remains unclear.

Interplay between SIRT proteins and tumour suppressor transcription factors in chemotherapeutic resistance of cancer.

Sirtuins, commonly referred to as SIRTs, are a family of seven mammalian NAD+-dependent deacetylases implicated in the regulation of critical biological processes, including metabolism, cell division, differentiation, survival, and senescence. These diverse functions reflect the ability of SIRTs to target and modify a broad spectrum of protein substrates, including cytoskeletal proteins, signalling components, transcription factors, and histones. SIRTs are also implicated in tumorigenesis as well as in the response of the tumour to chemotherapy.

Chromatin beacons: global sampling of chromatin physical properties using chromatin charting lines.

The extent to which physical properties and intranuclear locations of chromatin can influence transcription output remains unclear and poorly quantified. Because the scale and resolution at which structural parameters can be queried are usually so different from the scale that transcription outputs are measured, the integration of these data is often indirect. To overcome this limitation in quantifying chromatin structural parameters at different locations in the genome, a Chromatin Charting collection with 277 transposon-tagged Arabidopsis lines has been established in order to discover correlations between gene expression and the physical properties of chromatin loci within the nuclei.

Overexpression of proto-oncogene FBI-1 activates membrane type 1-matrix metalloproteinase in association with adverse outcome in ovarian cancers.

Background: FBI-1 (factor that binds to the inducer of short transcripts of human immunodeficiency virus-1) is a member of the POK (POZ and Kruppel) family of transcription factors and play important roles in cellular differentiation and oncogenesis. Recent evidence suggests that FBI-1 is expressed at high levels in a subset of human lymphomas and some epithelial solid tumors. However, the function of FBI-1 in human ovarian cancers remains elusive.

NADPH oxidase-derived reactive oxygen species mediate decidualization of human endometrial stromal cells in response to cyclic AMP signaling.

Differentiation of human endometrial stromal cells into specialized decidual cells is critical for embryo implantation and survival of the conceptus. Initiation of this differentiation process is strictly dependent on elevated cAMP levels, but the signal intermediates that control the expression of decidual marker genes, such as prolactin (PRL) and IGFBP1, remain poorly characterized. Here we show that cAMP-dependent decidualization can be attenuated or enhanced upon treatment of primary cultures with a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor (diphenylen iodonium) or activator (apocynin), respectively.

Factors associated with incomplete small bowel capsule endoscopy studies.

Aim: To identify patient risk factors associated with incomplete small bowel capsule endoscopy (CE) studies.

Methods: Data from all CE procedures performed at St. Paul's Hospital in Vancouver, British Columbia, Canada, between December 2001 and June 2008 were collected and analyzed on a retrospective basis.

Cyclin-dependent kinase 5 activity is required for T cell activation and induction of experimental autoimmune encephalomyelitis.

Cyclin-dependent kinase 5 (Cdk5) is a ubiquitously expressed serine/threonine kinase. However, a requirement for Cdk5 has been demonstrated only in postmitotic neurons where there is abundant expression of its activating partners p35 and/or p39. Although hyperactivation of the Cdk5-p35 complex has been found in a variety of inflammatory neurodegenerative disorders, the potential contribution of nonneuronal Cdk5-p35 activity has not been explored in this context.

Sustained spindle-assembly checkpoint response requires de novo transcription and translation of cyclin B1.

Background: Microtubule-targeting drugs induce mitotic delay at pro-metaphase by preventing the spindle assembly checkpoint to be satisfied. However, especially after prolonged treatments, cells can escape this arrest in a process called mitotic slippage. The mechanisms underlying the spindle assembly checkpoint and slippage are not fully understood.