Showing papers by "Novartis published in 2008"
TL;DR: This paper describes simultaneous inference procedures in general parametric models, where the experimental questions are specified through a linear combination of elemental model parameters, and extends the canonical theory of multiple comparison procedures in ANOVA models to linear regression problems, generalizedlinear models, linear mixed effects models, the Cox model, robust linear models, etc.
Abstract: Simultaneous inference is a common problem in many areas of application. If multiple null hypotheses are tested simultaneously, the probability of rejecting erroneously at least one of them increases beyond the pre-specified significance level. Simultaneous inference procedures have to be used which adjust for multiplicity and thus control the overall type I error rate. In this paper we describe simultaneous inference procedures in general parametric models, where the experimental questions are specified through a linear combination of elemental model parameters. The framework described here is quite general and extends the canonical theory of multiple comparison procedures in ANOVA models to linear regression problems, generalized linear models, linear mixed effects models, the Cox model, robust linear models, etc. Several examples using a variety of different statistical models illustrate the breadth
10,545 citations
TL;DR: Treatment with everolimus prolongs progression-free survival relative to placebo in patients with metastatic renal cell carcinoma that had progressed on other targeted therapies, but were mostly mild or moderate in severity.
2,822 citations
Daniel J. Klionsky1, Hagai Abeliovich2, Patrizia Agostinis3, Devendra K. Agrawal4 +232 more•Institutions (137)
TL;DR: A set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes are presented.
Abstract: Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms Recent reviews have described the range of assays that have been used for this purpose(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi) Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response
2,310 citations
Wellcome Trust Centre for Human Genetics1, University of Michigan2, University of Oxford3, Harvard University4, Massachusetts Institute of Technology5, Brigham and Women's Hospital6, Lund University7, Steno Diabetes Center8, University of Southern California9, National Institutes of Health10, Health Science University11, Novartis12, Ninewells Hospital13, University of Exeter14, University of Düsseldorf15, Queen Mary University of London16, Glostrup Hospital17, deCODE genetics18, University of Eastern Finland19, University of Cambridge20, Aarhus University21, University of North Carolina at Chapel Hill22, Norwegian University of Science and Technology23, Wellcome Trust Sanger Institute24, University of Bristol25, University of Helsinki26, Newcastle University27
TL;DR: The results illustrate the value of large discovery and follow-up samples for gaining further insights into the inherited basis of T2D, and detect at least six previously unknown loci with robust evidence for association.
Abstract: Genome-wide association (GWA) studies have identified multiple loci at which common variants modestly but reproducibly influence risk of type 2 diabetes (T2D). Established associations to common and rare variants explain only a small proportion of the heritability of T2D. As previously published analyses had limited power to identify variants with modest effects, we carried out meta-analysis of three T2D GWA scans comprising 10,128 individuals of European descent and approximately 2.2 million SNPs (directly genotyped and imputed), followed by replication testing in an independent sample with an effective sample size of up to 53,975. We detected at least six previously unknown loci with robust evidence for association, including the JAZF1 (P = 5.0 x 10(-14)), CDC123-CAMK1D (P = 1.2 x 10(-10)), TSPAN8-LGR5 (P = 1.1 x 10(-9)), THADA (P = 1.1 x 10(-9)), ADAMTS9 (P = 1.2 x 10(-8)) and NOTCH2 (P = 4.1 x 10(-8)) gene regions. Our results illustrate the value of large discovery and follow-up samples for gaining further insights into the inherited basis of T2D.
1,872 citations
TL;DR: The benazepril-amlodipine combination was superior in reducing cardiovascular events in patients with hypertension who were at high risk for such events.
Abstract: Background The optimal combination drug therapy for hypertension is not established, although current U.S. guidelines recommend inclusion of a diuretic. We hypothesized that treatment with the combination of an angiotensin-converting–enzyme (ACE) inhibitor and a dihydropyridine calcium-channel blocker would be more effective in reducing the rate of cardiovascular events than treatment with an ACE inhibitor plus a thiazide diuretic. Methods In a randomized, double-blind trial, we assigned 11,506 patients with hypertension who were at high risk for cardiovascular events to receive treatment with either benazepril plus amlodipine or benazepril plus hydrochlorothiazide. The primary end point was the composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, hospitalization for angina, resuscitation after sudden cardiac arrest, and coronary revascularization. Results The baseline characteristics of the two groups were similar. The trial was terminated early after a mean follow-up of 36 months, when the boundary of the prespecified stopping rule was exceeded. Mean blood pressures after dose adjustment were 131.6/73.3 mm Hg in the benazepril–amlodipine group and 132.5/74.4 mm Hg in the benazepril–hydrochlorothiazide group. There were 552 primary-outcome events in the benazepril–amlodipine group (9.6%) and 679 in the benazepril–hydrochlorothiazide group (11.8%), representing an absolute risk reduction with benazepril–amlodipine therapy of 2.2% and a relative risk reduction of 19.6% (hazard ratio, 0.80, 95% confidence interval [CI], 0.72 to 0.90; P<0.001). For the secondary end point of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke, the hazard ratio was 0.79 (95% CI, 0.67 to 0.92; P = 0.002). Rates of adverse events were consistent with those observed from clinical experience with the study drugs. Conclusions The benazepril–amlodipine combination was superior to the benazepril–hydrochlorothiazide combination in reducing cardiovascular events in patients with hypertension who were at high risk for such events. (ClinicalTrials.gov number, NCT00170950.)
1,825 citations
TL;DR: The most common functional groups that are amenable to prodrug design are described, and examples of prodrugs that are either launched or are undergoing human trials are highlighted.
Abstract: Prodrugs are bioreversible derivatives of drug molecules that undergo an enzymatic and/or chemical transformation in vivo to release the active parent drug, which can then exert the desired pharmacological effect. In both drug discovery and development, prodrugs have become an established tool for improving physicochemical, biopharmaceutical or pharmacokinetic properties of pharmacologically active agents. About 5-7% of drugs approved worldwide can be classified as prodrugs, and the implementation of a prodrug approach in the early stages of drug discovery is a growing trend. To illustrate the applicability of the prodrug strategy, this article describes the most common functional groups that are amenable to prodrug design, and highlights examples of prodrugs that are either launched or are undergoing human trials.
1,412 citations
TL;DR: In vivo studies suggest that inhibitors of the PI3K-mTOR pathway may be active in cancers with PIK3CA mutations and, when combined with MEK inhibitors, may effectively treat KRAS mutated lung cancers.
Abstract: Somatic mutations that activate phosphoinositide 3-kinase (PI3K) have been identified in the p110-alpha catalytic subunit (encoded by PIK3CA). They are most frequently observed in two hotspots: the helical domain (E545K and E542K) and the kinase domain (H1047R). Although the p110-alpha mutants are transforming in vitro, their oncogenic potential has not been assessed in genetically engineered mouse models. Furthermore, clinical trials with PI3K inhibitors have recently been initiated, and it is unknown if their efficacy will be restricted to specific, genetically defined malignancies. In this study, we engineered a mouse model of lung adenocarcinomas initiated and maintained by expression of p110-alpha H1047R. Treatment of these tumors with NVP-BEZ235, a dual pan-PI3K and mammalian target of rapamycin (mTOR) inhibitor in clinical development, led to marked tumor regression as shown by positron emission tomography-computed tomography, magnetic resonance imaging and microscopic examination. In contrast, mouse lung cancers driven by mutant Kras did not substantially respond to single-agent NVP-BEZ235. However, when NVP-BEZ235 was combined with a mitogen-activated protein kinase kinase (MEK) inhibitor, ARRY-142886, there was marked synergy in shrinking these Kras-mutant cancers. These in vivo studies suggest that inhibitors of the PI3K-mTOR pathway may be active in cancers with PIK3CA mutations and, when combined with MEK inhibitors, may effectively treat KRAS mutated lung cancers.
1,279 citations
TL;DR: This work focuses on the cellular and molecular mechanisms that enable CCR7 and its two ligands, CCL19 and CCL21, to balance immunity and tolerance.
Abstract: A key feature of the immune system is its ability to induce protective immunity against pathogens while maintaining tolerance towards self and innocuous environmental antigens. Recent evidence suggests that by guiding cells to and within lymphoid organs, CC-chemokine receptor 7 (CCR7) essentially contributes to both immunity and tolerance. This receptor is involved in organizing thymic architecture and function, lymph-node homing of naive and regulatory T cells via high endothelial venules, as well as steady state and inflammation-induced lymph-node-bound migration of dendritic cells via afferent lymphatics. Here, we focus on the cellular and molecular mechanisms that enable CCR7 and its two ligands, CCL19 and CCL21, to balance immunity and tolerance.
1,192 citations
TL;DR: The preclinical data show that NVP-BEZ235 is a potent dual PI3K/mTOR modulator with favorable pharmaceutical properties, and the compound was well tolerated, displayed disease stasis when administered orally, and enhanced the efficacy of other anticancer agents when used in in vivo combination studies.
Abstract: The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin inhibitor (mTOR) pathway is often constitutively activated in human tumor cells, providing unique opportunities for anticancer therapeutic intervention. NVP-BEZ235 is an imidazo[4,5-c]quinoline derivative that inhibits PI3K and mTOR kinase activity by binding to the ATP-binding cleft of these enzymes. In cellular settings using human tumor cell lines, this molecule is able to effectively and specifically block the dysfunctional activation of the PI3K pathway, inducing G(1) arrest. The cellular activity of NVP-BEZ235 translates well in in vivo models of human cancer. Thus, the compound was well tolerated, displayed disease stasis when administered orally, and enhanced the efficacy of other anticancer agents when used in in vivo combination studies. Ex vivo pharmacokinetic/pharmacodynamic analyses of tumor tissues showed a time-dependent correlation between compound concentration and PI3K/Akt pathway inhibition. Collectively, the preclinical data show that NVP-BEZ235 is a potent dual PI3K/mTOR modulator with favorable pharmaceutical properties. NVP-BEZ235 is currently in phase I clinical trials.
1,127 citations
TL;DR: The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization.
Abstract: Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization.
1,044 citations
TL;DR: PGC-1α and ERR-α, major regulators of mitochondrial function in response to exercise and other stimuli, also control a novel angiogenic pathway that delivers needed oxygen and substrates, and may provide a novel therapeutic target for treating ischaemic diseases.
Abstract: Ischaemia of the heart, brain and limbs is a leading cause of morbidity and mortality worldwide. Hypoxia stimulates the secretion of vascular endothelial growth factor (VEGF) and other angiogenic factors, leading to neovascularization and protection against ischaemic injury. Here we show that the transcriptional coactivator PGC-1alpha (peroxisome-proliferator-activated receptor-gamma coactivator-1alpha), a potent metabolic sensor and regulator, is induced by a lack of nutrients and oxygen, and PGC-1alpha powerfully regulates VEGF expression and angiogenesis in cultured muscle cells and skeletal muscle in vivo. PGC-1alpha-/- mice show a striking failure to reconstitute blood flow in a normal manner to the limb after an ischaemic insult, whereas transgenic expression of PGC-1alpha in skeletal muscle is protective. Surprisingly, the induction of VEGF by PGC-1alpha does not involve the canonical hypoxia response pathway and hypoxia inducible factor (HIF). Instead, PGC-1alpha coactivates the orphan nuclear receptor ERR-alpha (oestrogen-related receptor-alpha) on conserved binding sites found in the promoter and in a cluster within the first intron of the VEGF gene. Thus, PGC-1alpha and ERR-alpha, major regulators of mitochondrial function in response to exercise and other stimuli, also control a novel angiogenic pathway that delivers needed oxygen and substrates. PGC-1alpha may provide a novel therapeutic target for treating ischaemic diseases.
TL;DR: The human SIRT6 protein is an NAD+-dependent, histone H3 lysine 9 (H3K9) deacetylase that modulates telomeric chromatin and contributes to the propagation of a specialized chromatin state at mammalian telomeres, which in turn is required for proper telomere metabolism and function.
Abstract: The Sir2 deacetylase regulates chromatin silencing and lifespan in Saccharomyces cerevisiae. In mice, deficiency for the Sir2 family member SIRT6 leads to a shortened lifespan and a premature ageing-like phenotype. However, the molecular mechanisms of SIRT6 function are unclear. SIRT6 is a chromatin-associated protein, but no enzymatic activity of SIRT6 at chromatin has yet been detected, and the identity of physiological SIRT6 substrates is unknown. Here we show that the human SIRT6 protein is an NAD+-dependent, histone H3 lysine 9 (H3K9) deacetylase that modulates telomeric chromatin. SIRT6 associates specifically with telomeres, and SIRT6 depletion leads to telomere dysfunction with end-to-end chromosomal fusions and premature cellular senescence. Moreover, SIRT6-depleted cells exhibit abnormal telomere structures that resemble defects observed in Werner syndrome, a premature ageing disorder. At telomeric chromatin, SIRT6 deacetylates H3K9 and is required for the stable association of WRN, the factor that is mutated in Werner syndrome. We propose that SIRT6 contributes to the propagation of a specialized chromatin state at mammalian telomeres, which in turn is required for proper telomere metabolism and function. Our findings constitute the first identification of a physiological enzymatic activity of SIRT6, and link chromatin regulation by SIRT6 to telomere maintenance and a human premature ageing syndrome.
TL;DR: EZH1 partially complements Ezh2 in executing pluripotency during ESC differentiation, suggesting that cell-fate transitions require epigenetic specificity.
TL;DR: A model how de novo DNA methylation and dynamic switches in Polycomb targets restrict pluripotency and define the developmental potential of progenitor cells is suggested.
TL;DR: It is suggested that a redistribution of synaptic drive between silent and hyperactive neurons, rather than an overall decrease in synaptic activity, provides a mechanism for the disturbed cortical function in Alzheimer's disease.
Abstract: The neurodegeneration observed in Alzheimer's disease has been associated with synaptic dismantling and progressive decrease in neuronal activity. We tested this hypothesis in vivo by using two-photon Ca2+ imaging in a mouse model of Alzheimer's disease. Although a decrease in neuronal activity was seen in 29% of layer 2/3 cortical neurons, 21% of neurons displayed an unexpected increase in the frequency of spontaneous Ca2+ transients. These "hyperactive" neurons were found exclusively near the plaques of amyloid beta-depositing mice. The hyperactivity appeared to be due to a relative decrease in synaptic inhibition. Thus, we suggest that a redistribution of synaptic drive between silent and hyperactive neurons, rather than an overall decrease in synaptic activity, provides a mechanism for the disturbed cortical function in Alzheimer's disease.
TL;DR: In this paper, DNA methylation and Piwi-interacting small RNA (piRNA) expression were analyzed in wild-type, MILI-null, and MIWI2-null male fetal germ cells.
Abstract: Silencing of transposable elements occurs during fetal gametogenesis in males via de novo DNA methylation of their regulatory regions. The loss of MILI (miwi-like) and MIWI2 (mouse piwi 2), two mouse homologs of Drosophila Piwi, activates retrotransposon gene expression by impairing DNA methylation in the regulatory regions of the retrotransposons. However, as it is unclear whether the defective DNA methylation in the mutants is due to the impairment of de novo DNA methylation, we analyze DNA methylation and Piwi-interacting small RNA (piRNA) expression in wild-type, MILI-null, and MIWI2-null male fetal germ cells. We reveal that defective DNA methylation of the regulatory regions of the Line-1 (long interspersed nuclear elements) and IAP (intracisternal A particle) retrotransposons in the MILI-null and MIWI2-null male germ cells takes place at the level of de novo methylation. Comprehensive analysis shows that the piRNAs of fetal germ cells are distinct from those previously identified in neonatal and adult germ cells. The expression of piRNAs is reduced under MILI- and MIWI2-null conditions in fetal germ cells, although the extent of the reduction differs significantly between the two mutants. Our data strongly suggest that MILI and MIWI2 play essential roles in establishing de novo DNA methylation of retrotransposons in fetal male germ cells.
TL;DR: A new model of broad applicability is suggested, including examples of its implementation, and the size of the gene repertoire accessible to any given species is characterized together with an estimate of the number of whole genome sequences required for proper analysis.
Karolinska Institutet1, University of Oxford2, University of Toronto3, Centre national de la recherche scientifique4, University of California, Berkeley5, Los Alamos National Laboratory6, Tsinghua University7, University of Science and Technology of China8, Weizmann Institute of Science9, Scripps Research Institute10, Novartis11, Argonne National Laboratory12, Yeshiva University13, Brookhaven National Laboratory14, Rutgers University15, Case Western Reserve University16, University of California, San Francisco17, Columbia University18, Max Delbrück Center for Molecular Medicine19, New York University20
TL;DR: This review presents methods that could be applied at the outset of any project, a prioritized list of alternate strategies and a list of pitfalls that trip many new investigators.
Abstract: In selecting a method to produce a recombinant protein, a researcher is faced with a bewildering array of choices as to where to start. To facilitate decision-making, we describe a consensus 'what to try first' strategy based on our collective analysis of the expression and purification of over 10,000 different proteins. This review presents methods that could be applied at the outset of any project, a prioritized list of alternate strategies and a list of pitfalls that trip many new investigators.
TL;DR: Characteristics of dosing history in patients prescribed a once a day antihypertensive medication are described, finding that early discontinuation of treatment and suboptimal daily execution of the prescribed regimens are the most common facets of poor adherence with once aDay anti Hypertensive drug treatments.
Abstract: Objective To describe characteristics of dosing history in patients prescribed a once a day antihypertensive medication. Design Longitudinal database study. Setting Clinical studies archived in database for 1989-2006. Participants Patients who participated in the studies whose dosing histories were available through electronic monitoring. Main outcome measures Persistence with prescribed antihypertensive treatment and execution of their once a day drug dosing regimens. Results The database contained dosing histories of 4783 patients with hypertension. The data came from 21 phase IV clinical studies, with lengths ranging from 30 to 330 days and involving 43 different antihypertensive drugs, including angiotensin II receptor blockers (n=2088), calcium channel blockers (n=937), angiotensin converting enzyme inhibitors (n=665), β blockers (n=195), and diuretics (n=155). About half of the patients who were prescribed an antihypertensive drug had stopped taking it within one year. On any day, patients who were still engaged with the drug dosing regimen omitted about 10% of the scheduled doses: 42% of these omissions were of a single day’s dose, whereas 43% were part of a sequence of several days (three or more days—that is, drug “holidays”). Almost half of the patients had at least one drug holiday a year. The likelihood that a patient would discontinue treatment early was inversely related to the quality of his or her daily execution of the dosing regimen. Conclusions Early discontinuation of treatment and suboptimal daily execution of the prescribed regimens are the most common facets of poor adherence with once a day antihypertensive drug treatments. The shortfalls in drug exposure that these dosing errors create might be a common cause of low rates of blood pressure control and high variability in responses to prescribed antihypertensive drugs.
TL;DR: There was continuous circulation in east and Southeast Asia via a region-wide network of temporally overlapping epidemics and that epidemics in the temperate regions were seeded from this network each year, suggesting that once A (H3N2) viruses leave E-SE Asia, they are unlikely to contribute to long-term viral evolution.
Abstract: Antigenic and genetic analysis of the hemagglutinin of approximately 13,000 human influenza A (H3N2) viruses from six continents during 2002-2007 revealed that there was continuous circulation in east and Southeast Asia (E-SE Asia) via a region-wide network of temporally overlapping epidemics and that epidemics in the temperate regions were seeded from this network each year. Seed strains generally first reached Oceania, North America, and Europe, and later South America. This evidence suggests that once A (H3N2) viruses leave E-SE Asia, they are unlikely to contribute to long-term viral evolution. If the trends observed during this period are an accurate representation of overall patterns of spread, then the antigenic characteristics of A (H3N2) viruses outside E-SE Asia may be forecast each year based on surveillance within E-SE Asia, with consequent improvements to vaccine strain selection.
TL;DR: Evidence for an even greater degree of operational diversity is supported by the existence of a great number of splice and editing variants for several 5-HT receptors, their possible modulation by accessory proteins and chaperones, as well as their potential to form homo or heteromers both at the GPCR and at the ligand-gated channel level.
TL;DR: Overexpression of VEGFA via 6p21 gain in hepatocellular carcinomas suggested a novel, non-cell-autonomous mechanism of oncogene activation, and the prevalence of V EGFA high-level gains in multiple tumor types suggests indications for clinical trials of antiangiogenic therapies.
Abstract: Hepatocellular carcinomas represent the third leading cause of cancer-related deaths worldwide. The vast majority of cases arise in the context of chronic liver injury due to hepatitis B virus or hepatitis C virus infection. To identify genetic mechanisms of hepatocarcinogenesis, we characterized copy number alterations and gene expression profiles from the same set of tumors associated with hepatitis C virus. Most tumors harbored 1q gain, 8q gain, or 8p loss, with occasional alterations in 13 additional chromosome arms. In addition to amplifications at 11q13 in 6 of 103 tumors, 4 tumors harbored focal gains at 6p21 incorporating vascular endothelial growth factor A (VEGFA). Fluorescence in situ hybridization on an independent validation set of 210 tumors found 6p21 high-level gains in 14 tumors, as well as 2 tumors with 6p21 amplifications. Strikingly, this locus overlapped with copy gains in 4 of 371 lung adenocarcinomas. Overexpression of VEGFA via 6p21 gain in hepatocellular carcinomas suggested a novel, non-cell-autonomous mechanism of oncogene activation. Hierarchical clustering of gene expression among 91 of these tumors identified five classes, including "CTNNB1", "proliferation", "IFN-related", a novel class defined by polysomy of chromosome 7, and an unannotated class. These class labels were further supported by molecular data; mutations in CTNNB1 were enriched in the "CTNNB1" class, whereas insulin-like growth factor I receptor and RPS6 phosphorylation were enriched in the "proliferation" class. The enrichment of signaling pathway alterations in gene expression classes provides insights on hepatocellular carcinoma pathogenesis. Furthermore, the prevalence of VEGFA high-level gains in multiple tumor types suggests indications for clinical trials of antiangiogenic therapies.
TL;DR: The correlation of imatinib trough plasma concentrations with clinical responses, event-free survival (EFS), and adverse events (AEs) is described and it is suggested that an adequate plasma concentration ofImatinib is important for a good clinical response.
TL;DR: It is demonstrated that mice survive well without HDAC6 and that tubulin hyperacetylation is not detrimental to normal mammalian development, and that this deacetylase plays a minor role in bone biology.
Abstract: Posttranslational modifications play important roles in regulating protein structure and function. Histone deacetylase 6 (HDAC6) is a mostly cytoplasmic class II HDAC, which has a unique structure with two catalytic domains and a domain binding ubiquitin with high affinity. This enzyme was recently identified as a multisubstrate protein deacetylase that can act on acetylated histone tails, alpha-tubulin and Hsp90. To investigate the in vivo functions of HDAC6 and the relevance of tubulin acetylation/deacetylation, we targeted the HDAC6 gene by homologous recombination in embryonic stem cells and generated knockout mice. HDAC6-deficient mice are viable and fertile and show hyperacetylated tubulin in most tissues. The highest level of expression of HDAC6 is seen in the testis, yet development and function of this organ are normal in the absence of HDAC6. Likewise, lymphoid development is normal, but the immune response is moderately affected. Furthermore, the lack of HDAC6 results in a small increase in cancellous bone mineral density, indicating that this deacetylase plays a minor role in bone biology. HDAC6-deficient mouse embryonic fibroblasts show apparently normal microtubule organization and stability and also show increased Hsp90 acetylation correlating with impaired Hsp90 function. Collectively, these data demonstrate that mice survive well without HDAC6 and that tubulin hyperacetylation is not detrimental to normal mammalian development.
TL;DR: Although p110α activation is required to sustain the proliferation of established PIK3CA-mutant tumors, PTEN-deficient tumors are dependent instead on p110β signaling, demonstrating the need to tailor therapeutic approaches to the genetic basis of PI3K pathway activation to achieve optimal treatment response.
Abstract: Deregulation of the PI3K signaling pathway is observed in many human cancers and occurs most frequently through loss of PTEN phosphatase tumor suppressor function or through somatic activating mutations in the Class IA PI3K, PIK3CA. Tumors harboring activated p110α, the protein product of PIK3CA, require p110α activity for growth and survival and hence are expected to be responsive to inhibitors of its lipid kinase activity. Whether PTEN-deficient cancers similarly depend on p110α activity to sustain activation of the PI3K pathway has been unclear. In this study, we used a single-vector lentiviral inducible shRNA system to selectively inactivate the three Class IA PI3Ks, PIK3CA, PIK3CB, and PIK3CD, to determine which PI3K isoforms are responsible for driving the abnormal proliferation of PTEN-deficient cancers. Down-regulation of PIK3CA in colorectal cancer cells harboring mutations in PIK3CA inhibited downstream PI3K signaling and cell growth. Surprisingly, PIK3CA depletion affected neither PI3K signaling nor cell growth in 3 PTEN-deficient cancer cell lines. In contrast, down-regulation of the PIK3CB isoform, which encodes p110β, resulted in pathway inactivation and subsequent inhibition of growth in both cell-based and in vivo settings. This essential function of PIK3CB in PTEN-deficient cancer cells required its lipid kinase activity. Our findings demonstrate that although p110α activation is required to sustain the proliferation of established PIK3CA-mutant tumors, PTEN-deficient tumors are dependent instead on p110β signaling. This unexpected finding demonstrates the need to tailor therapeutic approaches to the genetic basis of PI3K pathway activation to achieve optimal treatment response.
TL;DR: Breast cancer patients with pathological stage 1 or 0 disease after neoadjuvant endocrine therapy and a low-risk biomarker profile in the surgical specimen (PEPI score 0) have an extremely low risk of relapse and are therefore unlikely to benefit from adjuvant chemotherapy.
Abstract: An accurate test to predict the effectiveness of adjuvant endocrine therapy for hormone receptor – positive breast cancer on an individual basis would be an important advance ( 1 ). Current approaches focus on biomarker analysis of the diagnostic specimen. An alternative is to treat patients with an endocrine agent for several months before surgery to identify tumors that are responsive to treatment, with the assumption that responsiveness indicates a lower risk of relapse. However, compared with neoadjuvant chemotherapy studies ( 2 ), fewer neoadjuvant endocrine therapy trials have been conducted; thus, fewer data are available to link postneoadjuvant therapy tumor characteristics and survival. The P024 neoadjuvant endocrine therapy trial, which compared 4 months of letrozole and tamoxifen before surgery ( 3 , 4 ), now has suffi cient follow-up (median >60 months) to address the relationships between postneoadjuvant endocrine therapy tumor characteristics and risk of early relapse. In this study, we used data from P024 to examine pathological stage posttreatment, histological grade posttreatment, response to treatment, and the biomarker status of the surgical specimen to develop a prognostic
TL;DR: The discovery of the amino-acetonitrile derivatives (AADs) as a new chemical class of synthetic anthelmintics and the development of drug candidates that are efficacious against various species of livestock-pathogenic nematodes are described.
Abstract: Anthelmintic resistance in human and animal pathogenic helminths has been spreading in prevalence and severity to a point where multidrug resistance against the three major classes of anthelmintics--the benzimidazoles, imidazothiazoles and macrocyclic lactones--has become a global phenomenon in gastrointestinal nematodes of farm animals. Hence, there is an urgent need for an anthelmintic with a new mode of action. Here we report the discovery of the amino-acetonitrile derivatives (AADs) as a new chemical class of synthetic anthelmintics and describe the development of drug candidates that are efficacious against various species of livestock-pathogenic nematodes. These drug candidates seem to have a novel mode of action involving a unique, nematode-specific clade of acetylcholine receptor subunits. The AADs are well tolerated and of low toxicity to mammals, and overcome existing resistances to the currently available anthelmintics.
TL;DR: It is shown that Hedgehog signaling is activated in LSCs through upregulation of Smo, and this indicates that Smo inhibition might be an effective treatment strategy to reduce the LSC pool in CML.
TL;DR: It is demonstrated that 35 amino acids of the carboxyl terminus of flagellin triggered inflammasome activation in the absence of bacterial contaminants or secretion systems, clarifying the molecular basis for the cytosolic response to flageLLin.
Abstract: Inflammasomes are cytosolic multiprotein complexes that sense microbial infection and trigger cytokine production and cell death. However, the molecular components of inflammasomes and what they sense remain poorly defined. Here we demonstrate that 35 amino acids of the carboxyl terminus of flagellin triggered inflammasome activation in the absence of bacterial contaminants or secretion systems. To further elucidate the host flagellin-sensing pathway, we generated mice deficient in the intracellular sensor Naip5. These mice failed to activate the inflammasome in response to the 35 amino acids of flagellin or in response to Legionella pneumophila infection. Our data clarify the molecular basis for the cytosolic response to flagellin.
TL;DR: The high bactericidal activity of the F0F1 ATP synthase inhibitor R207910 on hypoxic nonreplicating bacteria is described, supporting the potential of this drug candidate for shortening the time of tuberculosis therapy.
Abstract: The persistence of Mycobacterium tuberculosis despite prolonged chemotherapy represents a major obstacle for the control of tuberculosis. The mechanisms used by Mtb to persist in a quiescent state are largely unknown. Chemical genetic and genetic approaches were used here to study the physiology of hypoxic nonreplicating mycobacteria. We found that the intracellular concentration of ATP is five to six times lower in hypoxic nonreplicating Mtb cells compared with aerobic replicating bacteria, making them exquisitely sensitive to any further depletion. We show that de novo ATP synthesis is essential for the viability of hypoxic nonreplicating mycobacteria, requiring the cytoplasmic membrane to be fully energized. In addition, the anaerobic electron transport chain was demonstrated to be necessary for the generation of the protonmotive force. Surprisingly, the alternate ndh-2, but not -1, was shown to be the electron donor to the electron transport chain and to be essential to replenish the [NAD+] pool in hypoxic nonreplicating Mtb. Finally, we describe here the high bactericidal activity of the F0F1 ATP synthase inhibitor R207910 on hypoxic nonreplicating bacteria, supporting the potential of this drug candidate for shortening the time of tuberculosis therapy.