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Gene essentiality is typically determined by assessing the viability of the corresponding mutant cells, but this definition fails to account for the ability of cells to adaptively evolve to genetic perturbations. Here, we performed a stringent screen to assess the degree to which Saccharomyces cerevisiae cells can survive the deletion of ~1,000 individual "essential" genes and found that ~9% of these genetic perturbations could in fact be overcome by adaptive evolution. Our analyses uncovered a genome-wide gradient of gene essentiality, with certain essential cellular functions being more "evolvable" than others. Ploidy changes were prevalent among the evolved mutant strains, and aneuploidy of a specific chromosome was adaptive for a class of evolvable nucleoporin mutants. These data justify a quantitative redefinition of gene essentiality that incorporates both viability and evolvability of the corresponding mutant cells and will enable selection of therapeutic targets associated with lower risk of emergence of drug resistance.
Assuntos
Evolução Biológica , Genes Essenciais , Saccharomyces cerevisiae/genética , Deleção de Genes , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/citologia , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos/metabolismoRESUMO
Caveolin-1 (Cav1) is a 22â kDa intracellular protein that is the main protein constituent of bulb-shaped membrane invaginations known as caveolae. Cav1 can be also found in functional non-caveolar structures at the plasma membrane called scaffolds. Scaffolds were originally described as SDS-resistant oligomers composed of 10-15 Cav1 monomers observable as 8S complexes by sucrose velocity gradient centrifugation. Recently, cryoelectron microscopy (cryoEM) and super-resolution microscopy have shown that 8S complexes are interlocking structures composed of 11 Cav1 monomers each, which further assemble modularly to form higher-order scaffolds and caveolae. In addition, Cav1 can act as a critical signaling regulator capable of direct interactions with multiple client proteins, in particular, the endothelial nitric oxide (NO) synthase (eNOS), a role believed by many to be attributable to the highly conserved and versatile scaffolding domain (CSD). However, as the CSD is a hydrophobic domain located by cryoEM to the periphery of the 8S complex, it is predicted to be enmeshed in membrane lipids. This has led some to challenge its ability to interact directly with client proteins and argue that it impacts signaling only indirectly via local alteration of membrane lipids. Here, based on recent advances in our understanding of higher-order Cav1 structure formation, we discuss how the Cav1 CSD may function through both lipid and protein interaction and propose an alternate view in which structural modifications to Cav1 oligomers may impact exposure of the CSD to cytoplasmic client proteins, such as eNOS.
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Caveolina 1 , Transdução de Sinais , Animais , Humanos , Cavéolas/metabolismo , Caveolina 1/metabolismo , Caveolina 1/química , Membrana Celular/metabolismo , Microscopia Crioeletrônica , Óxido Nítrico Sintase Tipo III/metabolismo , Domínios ProteicosRESUMO
A novel series of 3-amino-piperidin-2-one-based calcitonin gene-related peptide (CGRP) receptor antagonists was invented based upon the discovery of unexpected structure-activity observations. Initial exploration of the structure-activity relationships enabled the generation of a moderately potent lead structure (4). A series of modifications, including ring contraction and inversion of stereocenters, led to surprising improvements in CGRP receptor affinity. These studies identified compound 23, a structurally novel potent, orally bioavailable CGRP receptor antagonist.
RESUMO
Para-hydroxycinnamic acid (pHCA) is one of the most abundant naturally occurring hydroxycinnamic acids, a class of chemistries known for their antioxidant properties. In this study, we evaluated the impact of pHCA on different parameters of skin aging in in vitro skin models after H2O2 and UV exposure. These parameters include keratinocyte senescence and differentiation, inflammation, and energy metabolism, as well as the underlying molecular mechanisms. Here we demonstrate that pHCA prevents oxidative stress-induced premature senescence of human primary keratinocytes in both 2D and 3D skin models, while improving clonogenicity in 2D. As aging is linked to inflammation, referred to as inflammaging, we analyzed the release of IL-6, IL-8, and PGE2, known to be associated with senescence. All of them were downregulated by pHCA in both normal and oxidative stress conditions. Mechanistically, DNA damage induced by oxidative stress is prevented by pHCA, while pHCA also exerts a positive effect on the mitochondrial and glycolytic functions under stress. Altogether, these results highlight the protective effects of pHCA against inflammaging, and importantly, help to elucidate its potential mechanisms of action.
Assuntos
Senescência Celular , Ácidos Cumáricos , Queratinócitos , Estresse Oxidativo , Envelhecimento da Pele , Pele , Humanos , Ácidos Cumáricos/farmacologia , Senescência Celular/efeitos dos fármacos , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Pele/metabolismo , Pele/efeitos dos fármacos , Envelhecimento da Pele/efeitos dos fármacos , Inflamação/metabolismo , Dano ao DNA/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Raios Ultravioleta/efeitos adversos , Antioxidantes/farmacologia , Células Cultivadas , Interleucina-8/metabolismo , Interleucina-6/metabolismoRESUMO
In the skin fragility disorder epidermolysis bullosa simplex (EBS), mutations in keratin 14 (K14, also known as KRT14) or keratin 5 (K5, also known as KRT5) lead to keratinocyte rupture and skin blistering. Severe forms of EBS are associated with cytoplasmic protein aggregates, with elevated kinase activation of ERK1 and ERK2 (ERK1/2; also known as MAPK3 and MAPK1, respectively), suggesting intrinsic stress caused by misfolded keratin protein. Human keratinocyte EBS reporter cells stably expressing GFP-tagged EBS-mimetic mutant K14 were used to optimize a semi-automated system to quantify the effects of test compounds on keratin aggregates. Screening of a protein kinase inhibitor library identified several candidates that reduced aggregates and impacted on epidermal growth factor receptor (EGFR) signalling. EGF ligand exposure induced keratin aggregates in EBS reporter keratinocytes, which was reversible by EGFR inhibition. EBS keratinocytes treated with a known EGFR inhibitor, afatinib, were driven out of activation and towards quiescence with minimal cell death. Aggregate reduction was accompanied by denser keratin filament networks with enhanced intercellular cohesion and resilience, which when extrapolated to a whole tissue context would predict reduced epidermal fragility in EBS patients. This assay system provides a powerful tool for discovery and development of new pathway intervention therapeutic avenues for EBS.
Assuntos
Epidermólise Bolhosa Simples , Citoesqueleto , Descoberta de Drogas , Epidermólise Bolhosa Simples/tratamento farmacológico , Epidermólise Bolhosa Simples/genética , Humanos , Filamentos Intermediários , Queratinócitos , Queratinas/genética , Mutação/genéticaRESUMO
LacY catalyzes accumulation of galactosides against a concentration gradient by coupling galactoside and H+ transport (i.e., symport). While alternating access of sugar- and H+-binding sites to either side of the membrane is driven by binding and dissociation of sugar, the electrochemical H+ gradient ([Formula: see text]) functions kinetically by decreasing the Km for influx 50- to 100-fold with no change in Kd The affinity of protonated LacY for sugar has an apparent pK (pKapp) of â¼10.5, due specifically to the pKa of Glu325, a residue that plays an irreplaceable role in coupling. In this study, rates of lactose/H+ efflux were measured from pH 5.0 to 9.0 in the absence or presence of a membrane potential (ΔΨ, interior positive), and the effect of the imposed ΔΨ on the kinetics of efflux was also studied in right-side-out membrane vesicles. The findings reveal that [Formula: see text] induces an asymmetry in the transport cycle based on the following observations: 1) the efflux rate of WT LacY exhibits a pKapp of â¼7.2 that is unaffected by the imposed ΔΨ; 2) ΔΨ increases the rate of efflux at all tested pH values, but enhancement is almost 2 orders of magnitude less than observed for influx; 3) mutant Glu325 - Ala does little or no efflux in the absence or presence of ΔΨ, and ambient pH has no effect; and 4) the effect of ΔΨ (interior positive) on the Km for efflux is almost insignificant relative to the 50- to 100-fold decrease in the Km for influx driven by ΔΨ (interior negative).
Assuntos
Galactosídeos/metabolismo , Potenciais da Membrana/fisiologia , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Prótons , Sítios de Ligação , Transporte Biológico , Concentração de Íons de Hidrogênio , Transporte de Íons , Cinética , Lactose/metabolismo , Proteínas de Membrana Transportadoras/genética , Modelos MolecularesRESUMO
Previous studies show that the main cannabinoid receptor in the brain-cannabinoid type 1 receptor (CB1R)-is required for establishment of axonal projections in developing neurons but questions remain regarding the cellular and molecular mechanisms, especially in neurons developing in their native environment. We assessed the effects of CB1R signalling on growth cone filopodia and axonal projections of retinal ganglion cells (RGCs) in whole mount brains from Xenopus laevis tadpoles. Our results indicate that growth cones of RGC axons in brains from tadpoles exposed to a CB1R agonist had fewer filopodial protrusions, whereas growth cones from tadpoles exposed to a CB1R inverse agonist had more filopodia than growth cones of RGC axons in whole brains from control tadpoles. However, application of both the CB1R agonist and inverse agonist resulted in RGC axons that were overly dispersed and undulatory in the optic tract in situ. In addition, expression of a mutant for cadherin adhesive factor, ß-catenin, that disrupts its binding to α-catenin, and application of an inhibitor for actin regulator non-muscle Myosin II, phenocopied the effects of the CB1R agonist and inverse agonist on growth cone filopodia, respectively. These findings suggest that both destablization and stabilization of growth cone filopodia are required for RGC axonal fasciculation/defasciculation in the optic tract and that CB1R regulates growth cone filopodia and axon dispersion of RGCs by oppositely modulating ß-catenin adhesive and Myosin II actin regulatory functions. This study extends and confirms our understanding of cannabinoid mechanisms in sculpting developing neuronal circuits in vivo.
Assuntos
Canabinoides , Trato Óptico , Actinas , Animais , Axônios/fisiologia , Canabinoides/metabolismo , Cones de Crescimento/metabolismo , Larva/metabolismo , Trato Óptico/metabolismo , Pseudópodes/metabolismo , Receptores de Canabinoides/metabolismo , Células Ganglionares da Retina , Xenopus laevis/metabolismo , beta Catenina/metabolismoRESUMO
Current therapeutic approaches to avoid or reverse bronchoconstriction rely primarily on ß2 adrenoceptor agonists (ß-agonists) that regulate pharmacomechanical coupling/cross bridge cycling in airway smooth muscle (ASM). Targeting actin cytoskeleton polymerization in ASM represents an alternative means to regulate ASM contraction. Herein we report the cooperative effects of targeting these distinct pathways with ß-agonists and inhibitors of the mammalian Abelson tyrosine kinase (Abl1 or c-Abl). The cooperative effect of ß-agonists (isoproterenol) and c-Abl inhibitors (GNF-5, or imatinib) on contractile agonist (methacholine, or histamine) -induced ASM contraction was assessed in cultured human ASM cells (using Fourier Transfer Traction Microscopy), in murine precision cut lung slices, and in vivo (flexiVent in mice). Regulation of intracellular signaling that regulates contraction (pMLC20, pMYPT1, pHSP20), and actin polymerization state (F:G actin ratio) were assessed in cultured primary human ASM cells. In each (cell, tissue, in vivo) model, c-Abl inhibitors and ß-agonist exhibited additive effects in either preventing or reversing ASM contraction. Treatment of contracted ASM cells with c-Abl inhibitors and ß-agonist cooperatively increased actin disassembly as evidenced by a significant reduction in the F:G actin ratio. Mechanistic studies indicated that the inhibition of pharmacomechanical coupling by ß-agonists is near optimal and is not increased by c-Abl inhibitors, and the cooperative effect on ASM relaxation resides in further relaxation of ASM tension development caused by actin cytoskeleton depolymerization, which is regulated by both ß-agonists and c-Abl inhibitors. Thus, targeting actin cytoskeleton polymerization represents an untapped therapeutic reserve for managing airway resistance.
Assuntos
Agonistas Adrenérgicos beta/farmacologia , Sinergismo Farmacológico , Contração Muscular , Relaxamento Muscular , Músculo Liso/fisiologia , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Traqueia/fisiologia , Citoesqueleto de Actina/metabolismo , Animais , Antineoplásicos/farmacologia , Benzamidas/farmacologia , Humanos , Mesilato de Imatinib/farmacologia , Isoproterenol/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Músculo Liso/citologia , Músculo Liso/efeitos dos fármacos , Pirimidinas/farmacologia , Transdução de Sinais , Traqueia/citologia , Traqueia/efeitos dos fármacosRESUMO
Exaggerated airway smooth muscle (ASM) contraction regulated by the Gq family of G protein-coupled receptors causes airway hyperresponsiveness in asthma. Activation of Gq-coupled G protein-coupled receptors leads to phospholipase C (PLC)-mediated generation of inositol triphosphate (IP3) and diacylglycerol (DAG). DAG signaling is terminated by the action of DAG kinase (DGK) that converts DAG into phosphatidic acid (PA). Our previous study demonstrated that DGKζ and α isoform knockout mice are protected from the development of allergen-induced airway hyperresponsiveness. Here we aimed to determine the mechanism by which DGK regulates ASM contraction. Activity of DGK isoforms was inhibited in human ASM cells by siRNA-mediated knockdown of DGKα and ζ, whereas pharmacological inhibition was achieved by pan DGK inhibitor I (R59022). Effects of DGK inhibition on contractile agonist-induced activation of PLC and myosin light chain (MLC) kinase, elevation of IP3, and calcium levels were assessed. Furthermore, we used precision-cut human lung slices and assessed the role of DGK in agonist-induced bronchoconstriction. DGK inhibitor I attenuated histamine- and methacholine-induced bronchoconstriction. DGKα and ζ knockdown or pretreatment with DGK inhibitor I resulted in attenuated agonist-induced phosphorylation of MLC and MLC phosphatase in ASM cells. Furthermore, DGK inhibition decreased Gq agonist-induced calcium elevation and generation of IP3 and increased histamine-induced production of PA. Finally, DGK inhibition or treatment with DAG analog resulted in attenuation of activation of PLC in human ASM cells. Our findings suggest that DGK inhibition perturbed the DAG:PA ratio, resulting in inhibition of Gq-PLC activation in a negative feedback manner, resulting in protection against ASM contraction.
Assuntos
Broncoconstrição/efeitos dos fármacos , Diacilglicerol Quinase/antagonistas & inibidores , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Contração Muscular/efeitos dos fármacos , Músculo Liso/enzimologia , Pirimidinonas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Tiazóis/farmacologia , Broncoconstrição/genética , Células Cultivadas , Diacilglicerol Quinase/genética , Diacilglicerol Quinase/metabolismo , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Técnicas de Silenciamento de Genes , Humanos , Contração Muscular/genética , Transdução de Sinais/genéticaRESUMO
BACKGROUND & AIMS: There are few in vitro models for studying the 3-dimensional interactions among different liver cell types during organogenesis or disease development. We aimed to generate hepatic organoids that comprise different parenchymal liver cell types and have structural features of the liver, using human pluripotent stem cells. METHODS: We cultured H1 human embryonic stem cells (WA-01, passage 27-40) and induced pluripotent stem cells (GM23338) with a series of chemically defined and serum-free media to induce formation of posterior foregut cells, which were differentiated in 3 dimensions into hepatic endoderm spheroids and stepwise into hepatoblast spheroids. Hepatoblast spheroids were reseeded in a high-throughput format and induced to form hepatic organoids; development of functional bile canaliculi was imaged live. Levels of albumin and apolipoprotein B were measured in cell culture supernatants using an enzyme-linked immunosorbent assay. Levels of gamma glutamyl transferase and alkaline phosphatase were measured in cholangiocytes. Organoids were incubated with troglitazone for varying periods and bile transport and accumulation were visualized by live-imaging microscopy. Organoids were incubated with oleic and palmitic acid, and formation of lipid droplets was visualized by staining. We compared gene expression profiles of organoids incubated with free fatty acids or without. We also compared gene expression profiles between liver tissue samples from patients with nonalcoholic steatohepatitis (NASH) versus without. We quantified hepatocyte and cholangiocyte populations in organoids using immunostaining and flow cytometry; cholangiocyte proliferation of cholangiocytes was measured. We compared the bile canaliculi network in the organoids incubated with versus without free fatty acids by live imaging. RESULTS: Cells in organoids differentiated into hepatocytes and cholangiocytes, based on the expression of albumin and cytokeratin 7. Hepatocytes were functional, based on secretion of albumin and apolipoprotein B and cytochrome P450 activity; cholangiocytes were functional, based on gamma glutamyl transferase and alkaline phosphatase activity and proliferative responses to secretin. The organoids organized a functional bile canaliculi system, which was disrupted by cholestasis-inducing drugs such as troglitazone. Organoids incubated with free fatty acids had gene expression signatures similar to those of liver tissues from patients with NASH. Incubation of organoids with free fatty acid-enriched media resulted in structural changes associated with nonalcoholic fatty liver disease, such as decay of bile canaliculi network and ductular reactions. CONCLUSIONS: We developed a hepatic organoid platform with human cells that can be used to model complex liver diseases, including NASH.
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Hepatócitos/citologia , Hepatopatias/etiologia , Hepatopatias/patologia , Organoides/crescimento & desenvolvimento , Células-Tronco Pluripotentes/fisiologia , Técnicas de Cultura de Células , Humanos , Modelos BiológicosRESUMO
Alexander Giaquinto and co-authors discuss the East African Community's Medicines Regulatory Harmonization initiative.
Assuntos
Medicina Comunitária/normas , Controle de Medicamentos e Entorpecentes , Acessibilidade aos Serviços de Saúde/normas , Guias de Prática Clínica como Assunto/normas , Qualidade da Assistência à Saúde/normas , África Oriental/epidemiologia , Medicina Comunitária/legislação & jurisprudência , Controle de Medicamentos e Entorpecentes/legislação & jurisprudência , Acessibilidade aos Serviços de Saúde/legislação & jurisprudência , Humanos , Qualidade da Assistência à Saúde/legislação & jurisprudênciaRESUMO
Data about patient reported outcomes from cancer genetics services (CGS) are lacking but are essential to guide service evaluation and improvements. We measured improvement in empowerment, following genetic counseling in Singapore using a culturally-adapted version of the Genetic Counseling Outcome Scale (GCOS-24); and sought to identify factors associated with change in empowerment. The GCOS-24 was administered to 155 patients of the CGS, at pre- and post-counseling or testing timepoints. Of which, 110 patients underwent genetic testing. Individual pre- and post-counseling responses were subjected to Rasch analysis; the scale was subsequently split into cognitive control (CC) and emotional control (EC) domains. Associations of baseline characteristics with changes in pre- and post-CC and EC scores were assessed using multiple regression analysis. Both CC and EC scores showed significant improvement following genetic counseling and testing. While all items in the CC domain of being showed increases at follow-up, aspects of EC related to alleviating negative emotions (P = .88) and hopelessness (P = .2) did not show significant improvement. Our study revealed significant improvement in empowerment in patients who have received cancer genetic counseling, while revealing a need to cultivate hope and facilitate the alleviation of negative emotions in patients during genetic counseling.
Assuntos
Aconselhamento Genético/normas , Testes Genéticos/normas , Medidas de Resultados Relatados pelo Paciente , Adulto , Emoções/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Singapura/epidemiologia , Inquéritos e QuestionáriosRESUMO
For decades, components of the mammalian nuclear envelope (NE), such as the nuclear lamina and nuclear pore complexes (NPCs), have been largely resistant to quantitative cell biological analysis using conventional fluorescence microscopy. This is in part due to their sub diffraction limit dimensions. Super-resolution microscopy, a major advancement in cell biology research, has now made possible the acquisition of images in which nuclear lamin networks and single NPCs can be resolved in intact mammalian somatic cells. In particular, single molecule localization microscopy is able to generate data sets that are accurate enough to allow detailed quantitative analysis. Here we describe an algorithm that will identify the centroid of single NPCs and will determine their localization relative to the distribution of lamin protein filaments. Using this algorithm, a percentage of NPCs localized within the nuclear lamin network was accurately calculated, that could be compared between cells expressing different lamin complements. With modifications tweaked according to user specified sample images, this algorithm serves as a semi-automatic and fast computational tool to quantify and compare the localization and distribution of two or more cellular components at the nanometre scale.
Assuntos
Técnicas Citológicas/métodos , Lâmina Nuclear/ultraestrutura , Poro Nuclear/ultraestrutura , Imagem Individual de Molécula/métodos , Algoritmos , Interface Usuário-ComputadorRESUMO
PURPOSE: This study aimed to identify patterns of relapse after neoadjuvant chemotherapy (NAC) for breast cancer to refine follow-up recommendations. METHODS: Retrospective analysis on 523 breast cancer patients treated with NAC at two public hospitals in Singapore between 2000 and 2014. RESULTS: Majority of patients (71.9%) had locally advanced disease. Median follow-up was 55 months. 5-year recurrence rate was significantly higher in triple negative breast cancer (TNBC) than non-TNBC subtypes (38.4% vs. 29.5%; p = 0.042); 85% of recurrences involved distant sites. Among TNBC and HR (hormone receptor)-/HER2+ subtypes, 97.0% and 95.0% of relapses occurred within 3 years from diagnosis respectively while 10.6% of relapses among HR+ subgroup occurred beyond 5 years. Recurrence risk in high-grade tumours decreased with time. Stage III at diagnosis (hazard ratio = 2.94; p < 0.001), grade 3 tumours (hazard ratio = 2.87; p = 0.018), not achieving pathologic complete response (pCR) (hazard ratio = 8.77; p = 0.003) and not receiving adjuvant radiotherapy (hazard ratio = 3.19; p < 0.001) were independent predictors of inferior recurrence-free survival. Serum CA 15-3 was raised in 49% of patients upon relapse; it correlated with inferior post-relapse survival (median 11 months vs. 22 months; p = 0.019). CONCLUSIONS: While more intensive follow-up during the first 3 years may be required for patients who do not achieve pCR, especially those with TNBC and HR-/HER2+ tumours, the benefit from blood tests such as CA 15-3 appears limited, and the benefit from intensification of surveillance remains to be addressed in prospective studies on high-risk patients.
Assuntos
Neoplasias da Mama/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/etiologia , Quimioterapia Adjuvante , Terapia Combinada , Gerenciamento Clínico , Feminino , Seguimentos , Pesquisas sobre Atenção à Saúde , Humanos , Testes de Função Hepática , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Padrões de Prática Médica , Estudos Retrospectivos , Fatores de Risco , Análise de Sobrevida , Resultado do Tratamento , Adulto JovemRESUMO
The rate of reaction between N, N'-dicyclohexylbarbituric acid 1 and ethyl 2-isocyanatoacetate 2 is invariant with temperature. Positive orders in each reactant and dissociation of triethylammonium salts of 1 and product 3 at elevated temperature indicate that reaction occurs via a catalytic mechanism where changes to the positions of equilibria negate changes in the rate of the turnover-limiting step. A model for the consumption of 1 in a flow reactor accurately predicted the outcome of a laboratory-scale multivariate study.
Assuntos
Barbitúricos/síntese química , Preparações Farmacêuticas/síntese química , Temperatura , Barbitúricos/química , Estrutura Molecular , Preparações Farmacêuticas/químicaRESUMO
Access to quality-assured medical products improves health and save lives. However, one third of the world's population lacks timely access to quality-assured medicines while estimates indicate that at least 10% of medicine in low- and middle-income countries (LMICs) are substandard or falsified (SF), costing approximately US$ 31 billion annually. National regulatory authorities are the key government institutions that promote access to quality-assured medicines and combat SF medical products but despite progress, regulatory capacity in LMICs is still insufficient. Continued and increased investment in regulatory system strengthening (RSS) is needed. We have therefore reviewed existing global normative documents and resources and engaged with our networks of global partners and stakeholders to identify three critical challenges being faced by NRAs in LMICs that are limiting access to medical products and impeding detection of and response to SF medicines. The challenges are; implementing value-added regulatory practices that best utilize available resources, a lack of timely access to new, quality medical products, and limited evidence-based data to support post-marketing regulatory actions. To address these challenges, we have identified seven focused strategies; advancing and leveraging convergence and reliance initiatives, institutionalizing sustainability, utilizing risk-based approaches for resource allocation, strengthening registration efficiency and timeliness, strengthening inspection capacity and effectiveness, developing and implementing risk-based post-marketing quality surveillance systems, and strengthening regulatory management of manufacturing variations. These proposed solutions are underpinned by 13 focused recommendations, which we believe, if financed, technically supported and implemented, will lead to stronger health system and as a consequence, positive health outcomes.
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Países em Desenvolvimento , Medicamentos Essenciais/provisão & distribuição , Saúde Global/economia , Prioridades em Saúde , Humanos , Legislação de MedicamentosRESUMO
Dysregulation of MYC is frequently implicated in both early and late myeloma progression events, yet its therapeutic targeting has remained a challenge. Among key MYC downstream targets is ribosomal biogenesis, enabling increases in protein translational capacity necessary to support the growth and self-renewal programmes of malignant cells. We therefore explored the selective targeting of ribosomal biogenesis with the small molecule RNA polymerase (pol) I inhibitor CX-5461 in myeloma. CX-5461 induced significant growth inhibition in wild-type (WT) and mutant TP53 myeloma cell lines and primary samples, in association with increases in downstream markers of apoptosis. Moreover, Pol I inhibition overcame adhesion-mediated drug resistance and resistance to conventional and novel agents. To probe the TP53-independent mechanisms of CX-5461, gene expression profiling was performed on isogenic TP53 WT and knockout cell lines and revealed reduction of MYC downstream targets. Mechanistic studies confirmed that CX-5461 rapidly suppressed both MYC protein and MYC mRNA levels. The latter was associated with an increased binding of the RNA-induced silencing complex (RISC) subunits TARBP2 and AGO2, the ribosomal protein RPL5, and MYC mRNA, resulting in increased MYC transcript degradation. Collectively, these studies provide a rationale for the clinical translation of CX-5461 as a novel therapeutic approach to target MYC in myeloma.
Assuntos
Antineoplásicos/farmacologia , Benzotiazóis/farmacologia , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Naftiridinas/farmacologia , Proteínas Proto-Oncogênicas c-myc/genética , RNA Polimerase I/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Benzotiazóis/uso terapêutico , Linhagem Celular Tumoral , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Expressão Gênica , Perfilação da Expressão Gênica , Humanos , Camundongos , Terapia de Alvo Molecular , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/patologia , Mutação , Naftiridinas/uso terapêutico , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Polimerase I/metabolismo , Carga Tumoral/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The colon differs regionally in local luminal environment, excretory function, and gene expression. Polycistronic microRNA (miR)-143 and miR-145 are downregulated early in colon cancer. We asked if these microRNAs (miRNAs) might be differentially expressed in the proximal vs. the distal colon, contributing to regional differences in protein expression. Primary transcripts and mature miR-143 and miR-145 were quantified by real-time PCR, putative targets were measured by Western blotting, and DNA methylation was assessed by sequencing bisulfite-treated DNA in proximal and distal normal colonic mucosa as well as colon cancers. Putative targets of these miRNAs were assessed following transfection with miR-143 or miR-145. Mean expression of mature miR-143 and miR-145 was 2.0-fold (P < 0.001) and 1.8-fold (P = 0.03) higher, respectively, in proximal than distal colon. DNA methylation or primary transcript expression of these miRNAs did not differ by location. In agreement with increased expression of miR-143 and miR-145 in proximal colon, predicted targets of these miRNAs, apoptosis inhibitor 5 (API5), ERK5, K-RAS, and insulin receptor substrate 1 (IRS-1), which are cell cycle and survival regulators, were expressed at a lower level in proximal than distal colon. Transfection of HCA-7 colon cancer cells with miR-145 downregulated IRS-1, and transfection of HT-29 colon cancer cells with miR-143 decreased K-RAS and ERK5 expression. In conclusion, miR-143 and miR-145 and the predicted target proteins API5, ERK5, K-RAS, and IRS-1 display regional differences in expression in the colon. We speculate that differences in these tumor suppressors might contribute to regional differences in normal colonic gene expression and modulate site-specific differences in malignant predisposition.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Colo/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , MicroRNAs/metabolismo , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas ras/metabolismo , Adulto , Ciclo Celular , Linhagem Celular Tumoral , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Proteínas Proto-Oncogênicas p21(ras) , Reação em Cadeia da Polimerase em Tempo Real/métodos , Adulto JovemRESUMO
Light sheet fluorescence microscopy (LSFM) has emerged as an important imaging modality to follow biology in live 3D samples over time with reduced phototoxicity and photobleaching. In particular, LSFM has been instrumental in revealing the detail of early embryonic development of Zebrafish, Drosophila, and C. elegans. Open access projects, DIY-SPIM, OpenSPIM, and OpenSPIN, now allow LSFM to be set-up easily and at low cost. The aim of this paper is to facilitate the set-up and use of LSFM by reviewing and comparing open access projects, image processing tools and future challenges.
Assuntos
Microscopia de Fluorescência , Animais , Rastreamento de Células , Desenvolvimento Embrionário , Processamento de Imagem Assistida por Computador , Microscopia Confocal , Reconhecimento Automatizado de PadrãoRESUMO
BACKGROUND: Inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal soft tissue sarcomas that often present diagnostic challenges due to their wide and varied morphology. A subset of IMTs have fusions involving ALK or ROS1. The role of next-generation sequencing (NGS) for classification of unselected sarcomas remains controversial. METHODS AND RESULTS: We report a case of a metastatic sarcoma in a 34-year-old female originally diagnosed as an unclassified spindle cell sarcoma with myofibroblastic differentiation and later reclassified as IMT after NGS revealed a TFG-ROS1 rearrangement. Histologically, the neoplasm had spindle cell morphology with a lobulated to focally infiltrative growth pattern with scant inflammatory cell infiltrate. Immunohistochemistry demonstrated focal desmin and variable smooth muscle actin staining but was negative for SOX10, S100, and CD34. Fluorescence in situ hybridization was negative for USP6 or ALK gene rearrangements. NGS revealed a TFG-ROS1 rearrangement and the patient was treated with crizotinib with clinical benefit. CONCLUSIONS: We discuss the role of NGS as well as its potential benefit in patients with unresectable, ALK-negative metastatic disease. Considering this case and previous literature, we support the use of NGS for patients requiring systemic treatment.