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1.
Nature ; 609(7926): 416-423, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35830882

RESUMEN

RAS-MAPK signalling is fundamental for cell proliferation and is altered in most human cancers1-3. However, our mechanistic understanding of how RAS signals through RAF is still incomplete. Although studies revealed snapshots for autoinhibited and active RAF-MEK1-14-3-3 complexes4, the intermediate steps that lead to RAF activation remain unclear. The MRAS-SHOC2-PP1C holophosphatase dephosphorylates RAF at serine 259, resulting in the partial displacement of 14-3-3 and RAF-RAS association3,5,6. MRAS, SHOC2 and PP1C are mutated in rasopathies-developmental syndromes caused by aberrant MAPK pathway activation6-14-and SHOC2 itself has emerged as potential target in receptor tyrosine kinase (RTK)-RAS-driven tumours15-18. Despite its importance, structural understanding of the SHOC2 holophosphatase is lacking. Here we determine, using X-ray crystallography, the structure of the MRAS-SHOC2-PP1C complex. SHOC2 bridges PP1C and MRAS through its concave surface and enables reciprocal interactions between all three subunits. Biophysical characterization indicates a cooperative assembly driven by the MRAS GTP-bound active state, an observation that is extendible to other RAS isoforms. Our findings support the concept of a RAS-driven and multi-molecular model for RAF activation in which individual RAS-GTP molecules recruit RAF-14-3-3 and SHOC2-PP1C to produce downstream pathway activation. Importantly, we find that rasopathy and cancer mutations reside at protein-protein interfaces within the holophosphatase, resulting in enhanced affinities and function. Collectively, our findings shed light on a fundamental mechanism of RAS biology and on mechanisms of clinically observed enhanced RAS-MAPK signalling, therefore providing the structural basis for therapeutic interventions.


Asunto(s)
Cristalografía por Rayos X , Péptidos y Proteínas de Señalización Intracelular , Complejos Multiproteicos , Proteína Fosfatasa 1 , Proteínas ras , Proteínas 14-3-3 , Guanosina Trifosfato/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Sistema de Señalización de MAP Quinasas , Complejos Multiproteicos/química , Mutación , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Proteína Fosfatasa 1/química , Proteína Fosfatasa 1/genética , Proteína Fosfatasa 1/metabolismo , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Quinasas raf , Proteínas ras/química , Proteínas ras/metabolismo
2.
Nature ; 575(7783): 545-550, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31581174

RESUMEN

RAF family kinases are RAS-activated switches that initiate signalling through the MAP kinase cascade to control cellular proliferation, differentiation and survival1-3. RAF activity is tightly regulated and inappropriate activation is a frequent cause of cancer4-6; however, the structural basis for RAF regulation is poorly understood at present. Here we use cryo-electron microscopy to determine autoinhibited and active-state structures of full-length BRAF in complexes with MEK1 and a 14-3-3 dimer. The reconstruction reveals an inactive BRAF-MEK1 complex restrained in a cradle formed by the 14-3-3 dimer, which binds the phosphorylated S365 and S729 sites that flank the BRAF kinase domain. The BRAF cysteine-rich domain occupies a central position that stabilizes this assembly, but the adjacent RAS-binding domain is poorly ordered and peripheral. The 14-3-3 cradle maintains autoinhibition by sequestering the membrane-binding cysteine-rich domain and blocking dimerization of the BRAF kinase domain. In the active state, these inhibitory interactions are released and a single 14-3-3 dimer rearranges to bridge the C-terminal pS729 binding sites of two BRAFs, which drives the formation of an active, back-to-back BRAF dimer. Our structural snapshots provide a foundation for understanding normal RAF regulation and its mutational disruption in cancer and developmental syndromes.


Asunto(s)
Proteínas 14-3-3/antagonistas & inhibidores , Proteínas 14-3-3/química , Microscopía por Crioelectrón , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 1/química , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/química , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Sitios de Unión , Transformación Celular Neoplásica/genética , Humanos , MAP Quinasa Quinasa 1/genética , MAP Quinasa Quinasa 1/metabolismo , Modelos Moleculares , Mutación , Fosforilación , Unión Proteica , Dominios Proteicos , Multimerización de Proteína , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo
3.
J Biol Chem ; 299(5): 104634, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36963492

RESUMEN

Upon activation by RAS, RAF family kinases initiate signaling through the MAP kinase cascade to control cell growth, proliferation, and differentiation. Among RAF isoforms (ARAF, BRAF, and CRAF), oncogenic mutations are by far most frequent in BRAF. The BRAFV600E mutation drives more than half of all malignant melanoma and is also found in many other cancers. Selective inhibitors of BRAFV600E (vemurafenib, dabrafenib, encorafenib) are used clinically for these indications, but they are not effective inhibitors in the context of oncogenic RAS, which drives dimerization and activation of RAF, nor for malignancies driven by aberrantly dimerized truncation/fusion variants of BRAF. By contrast, a number of "type II" RAF inhibitors have been developed as potent inhibitors of RAF dimers. Here, we compare potency of type II inhibitors tovorafenib (TAK-580) and naporafenib (LHX254) in biochemical assays against the three RAF isoforms and describe crystal structures of both compounds in complex with BRAF. We find that tovorafenib and naporafenib are most potent against CRAF but markedly less potent against ARAF. Crystal structures of both compounds with BRAFV600E or WT BRAF reveal the details of their molecular interactions, including the expected type II-binding mode, with full occupancy of both subunits of the BRAF dimer. Our findings have important clinical ramifications. Type II RAF inhibitors are generally regarded as pan-RAF inhibitors, but our studies of these two agents, together with recent work with type II inhibitors belvarafenib and naporafenib, indicate that relative sparing of ARAF may be a property of multiple drugs of this class.


Asunto(s)
Modelos Moleculares , Inhibidores de Proteínas Quinasas , Proteínas Proto-Oncogénicas B-raf , Humanos , Línea Celular Tumoral , Cristalografía por Rayos X , Sistema de Señalización de MAP Quinasas , Melanoma/tratamiento farmacológico , Estructura Molecular , Mutación , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/química , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo
4.
J Synchrotron Radiat ; 31(Pt 3): 469-477, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38517754

RESUMEN

Various X-ray techniques are employed to investigate specimens in diverse fields. Generally, scattering and absorption/emission processes occur due to the interaction of X-rays with matter. The output signals from these processes contain structural information and the electronic structure of specimens, respectively. The combination of complementary X-ray techniques improves the understanding of complex systems holistically. In this context, we introduce a multiplex imaging instrument that can collect small-/wide-angle X-ray diffraction and X-ray emission spectra simultaneously to investigate morphological information with nanoscale resolution, crystal arrangement at the atomic scale and the electronic structure of specimens.

5.
Hum Resour Health ; 22(1): 39, 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38872223

RESUMEN

BACKGROUND: According to previous studies, stress and job burnout among medical personnel increased during the COVID-19 pandemic. This study analyzed the effect of the experience of COVID-19 response work on the intention of municipal hospital staffs to leave their workplaces during the pandemic. METHODS: The 3556 employees who had worked for more than 1 year at one of the eight Seoul Municipal Hospitals that either provided inpatient treatment for quarantined COVID-19 patients or operated as screening clinics were taken as the study population. In total, 1227 employees completed a web or mobile survey between October 21 and November 18, 2020. A chi-squared test was performed to confirm the difference in the distribution of turnover intention depending on whether the employees performed COVID-19 response tasks. Multiple logistic regression analyses were performed to determine the factors that affected the intention to leave. RESULTS: Of the 1227 respondents, 761 (62.0%) were frontline workers who were the first line of response to COVID-19. Experience with COVID-19 response tasks (OR = 1.59, p = 0.003) was significantly associated with the intention to leave. Additionally, the probability of turnover intention was significantly higher among workers aged 20-29 years (OR = 2.11, p = 0.038) and 40-49 years (OR = 1.57, p = 0.048), unmarried individuals (OR = 1.66, p = 0.005), doctors (OR = 2.41, p = 0.010), nurses (OR = 1.59, p = 0.036), and technical staff members (OR = 2.22, p = 0.009). High turnover intention was found among those who experienced high levels of burnout (OR = 2.03, p < 0.001) and those working in non-directly managed municipal hospitals (OR = 1.87, p = 0.018). CONCLUSION: Employees directly involved in COVID-19 response work displayed higher turnover intention. Various personal, job, and organizational factors significantly influenced employees' intentions to leave their positions in dedicated COVID-19 hospitals. These findings suggest the necessity of introducing management programs to aid workers who have experienced sudden changes in their duties and loss of autonomy while performing COVID-19 response tasks.


Asunto(s)
Agotamiento Profesional , COVID-19 , Intención , Reorganización del Personal , SARS-CoV-2 , Humanos , COVID-19/epidemiología , COVID-19/psicología , Reorganización del Personal/estadística & datos numéricos , Adulto , Masculino , Femenino , Agotamiento Profesional/epidemiología , Persona de Mediana Edad , Seúl , Encuestas y Cuestionarios , Personal de Hospital/psicología , Adulto Joven , Lugar de Trabajo/psicología , Pandemias , Satisfacción en el Trabajo
6.
Proc Natl Acad Sci U S A ; 118(36)2021 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-34470822

RESUMEN

The RAF/MEK/ERK pathway is central to the control of cell physiology, and its dysregulation is associated with many cancers. Accordingly, the proteins constituting this pathway, including MEK1/2 (MEK), have been subject to intense drug discovery and development efforts. Allosteric MEK inhibitors (MEKi) exert complex effects on RAF/MEK/ERK pathway signaling and are employed clinically in combination with BRAF inhibitors in malignant melanoma. Although mechanisms and structures of MEKi bound to MEK have been described for many of these compounds, recent studies suggest that RAF/MEK complexes, rather than free MEK, should be evaluated as the target of MEKi. Here, we describe structural and biochemical studies of eight structurally diverse, clinical-stage MEKi to better understand their mechanism of action on BRAF/MEK complexes. We find that all of these agents bind in the MEK allosteric site in BRAF/MEK complexes, in which they stabilize the MEK activation loop in a conformation that is resistant to BRAF-mediated dual phosphorylation required for full activation of MEK. We also show that allosteric MEK inhibitors act most potently on BRAF/MEK complexes rather than on free active MEK, further supporting the notion that a BRAF/MEK complex is the physiologically relevant pharmacologic target for this class of compounds. Our findings provide a conceptual and structural framework for rational development of RAF-selective MEK inhibitors as an avenue to more effective and better-tolerated agents targeting this pathway.


Asunto(s)
Quinasas Quinasa Quinasa PAM/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/metabolismo , Regulación Alostérica , Activación Enzimática , Estabilidad de Enzimas , Humanos , Quinasas Quinasa Quinasa PAM/química , Quinasas Quinasa Quinasa PAM/metabolismo , Fosforilación , Conformación Proteica , Transducción de Señal
7.
BMC Nurs ; 23(1): 78, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38291434

RESUMEN

BACKGROUND: In nursing research and practice, there is a paucity of information about how fathers perceive their role in shaping their children's health behaviors. Most studies on the parental factors affecting children's health behaviors have focused on the role of mothers. However, recent studies showed that fathers' health behaviors can influence those of their children. Therefore, the aim of this study was to synthesize existing qualitative studies to explore fathers' perspectives regarding how they influence children's obesity-related health behaviors. METHODS: We conducted a descriptive meta-synthesis. To retrieve relevant articles, we used databases including PubMed, CINAHL, and Web of Science. Only qualitative studies published in English-language peer-reviewed journals, targeting fathers of children aged 2-18 years, and focusing on fathers' perspectives were included. All the quotes collected from the studies were reviewed and coded, and thematic analysis was used to derive themes. RESULTS: Article screening and review yielded a total of 13 qualitative studies, from which the following themes emerged: (1) fathers' parenting practices and role-modeling behaviors, (2) fathers' roles in their relationships with their family members, and (3) fathers' resource-seeking behaviors and contributions to their home food environment. Fathers were aware that their parenting practices and role-modeling behaviors could influence their children's health behaviors. Furthermore, fathers recognized the importance of their relationships with family members, which was reflected in their family roles; that is, whether they took responsibility for childcare and household work, whether their parenting practices were similar to those of their spouses, and whether they involved their children in their activities. Fathers also reported their resource-seeking behaviors as well as their contribution to the home food environment, which affected their children's health behaviors. CONCLUSION: Fathers' perspectives on their influence on children's health behaviors reveal their unique paternal role in influencing children's health behaviors. Fathers' perspectives could be incorporated into future nursing research to examine the relationship between fathers' roles and children's health behaviors to develop better health intervention programs.

8.
Biophys J ; 122(9): 1691-1700, 2023 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-36987391

RESUMEN

The brain cells are affected by continuous fluid shear stress that is driven by varying hydrostatic and osmotic pressure conditions, depending on the brain's pathophysiological conditions. Although all brain cells are sensitive to the subtle changes in various physicochemical factors in the microenvironment, microglia, the resident brain immune cells, exhibit the most significant morphodynamic transformation. However, little is known about the phenotypic alterations in microglia in response to changes in fluid shear stress. In this study, we established a flow-controlled microenvironment to investigate the effects of shear flow on microglial phenotypes, including morphology, motility, and activation states. We observed two distinct morphologies of microglia in a static condition: bipolar cells that oscillate along their long axis and unipolar cells that migrate persistently. When exposed to flow, a significant fraction of bipolar cells showed unstable oscillation with an increased amplitude of oscillation and a decreased frequency, which consequently led to the phenotypic transformation of oscillating cells into migrating cells. Furthermore, we observed that the level of proinflammatory genes increased in response to shear stress, although there were no significant changes in the level of antiinflammatory genes. Our findings suggest that an interstitial fluid-level stimulus can cause a dramatic phenotypic shift in microglia toward proinflammatory states, shedding light on the pathological outbreaks of severe brain diseases. Given that the fluidic environment in the brain can be locally disrupted in pathological circumstances, the mechanical stimulus by fluid flow should also be considered a crucial element in regulating the immune activities of the microglia in brain diseases.


Asunto(s)
Encefalopatías , Microglía , Humanos , Microglía/patología , Microglía/fisiología , Encéfalo , Encefalopatías/patología , Antiinflamatorios
9.
Am J Epidemiol ; 192(8): 1406-1414, 2023 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-37092245

RESUMEN

Regression calibration is a popular approach for correcting biases in estimated regression parameters when exposure variables are measured with error. This approach involves building a calibration equation to estimate the value of the unknown true exposure given the error-prone measurement and other covariates. The estimated, or calibrated, exposure is then substituted for the unknown true exposure in the health outcome regression model. When used properly, regression calibration can greatly reduce the bias induced by exposure measurement error. Here, we first provide an overview of the statistical framework for regression calibration, specifically discussing how a special type of error, called Berkson error, arises in the estimated exposure. We then present practical issues to consider when applying regression calibration, including: 1) how to develop the calibration equation and which covariates to include; 2) valid ways to calculate standard errors of estimated regression coefficients; and 3) problems arising if one of the covariates in the calibration model is a mediator of the relationship between the exposure and outcome. Throughout, we provide illustrative examples using data from the Hispanic Community Health Study/Study of Latinos (United States, 2008-2011) and simulations. We conclude with recommendations for how to perform regression calibration.


Asunto(s)
Salud Pública , Humanos , Calibración , Análisis de Regresión , Sesgo
10.
BMC Neurol ; 23(1): 237, 2023 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-37340392

RESUMEN

BACKGROUND: The Caregiving Difficulty Scale is used to measure the burden of caregiving experienced by mothers of children with cerebral palsy. This study aimed to identify the psychometric properties of the Caregiving Difficulty Scale using the Rasch model. METHODS: Data collected from 206 mothers of children with cerebral palsy were analyzed. Unidimensionality, difficulty of item, rating scale appropriateness, and reliability using the separation index of the Caregiving Difficulty Scale were verified. Unidimensionality of all 25 items was identified through the item fit. RESULTS: Our analysis of item difficulty indicated that person ability and item difficulty are expressed as a similar logit extend. The use of the 5-point rating scale appeared to be appropriate. Outcome analysis revealed that the reliability was high based on the person and that the item separation level was acceptable. CONCLUSIONS: This study showed that the Caregiving Difficulty Scale could be a valuable tool for evaluating the caregiving burden in mothers of children with cerebral palsy.


Asunto(s)
Parálisis Cerebral , Madres , Femenino , Humanos , Niño , Psicometría , Reproducibilidad de los Resultados
11.
Mol Ther ; 30(8): 2800-2816, 2022 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-35526096

RESUMEN

Several preclinical studies demonstrate that antitumor efficacy of programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) blockade can be improved by combination with other checkpoint inhibitors. Lymphocyte-activation gene 3 (LAG-3) is an inhibitory checkpoint receptor involved in T cell exhaustion and tumor immune escape. Here, we describe ABL501, a bispecific antibody targeting LAG-3 and PD-L1 in modulating immune cell responses against tumors. ABL501 that efficiently inhibits both LAG-3 and PD-L1 pathways enhances the activation of effector CD4+ and CD8+ T cells with a higher degree than a combination of single anti-LAG-3 and anti-PD-L1. The augmented effector T cell responses by ABL501 resulted in mitigating regulatory-T-cell-mediated immunosuppression. Mechanistically, the simultaneous binding of ABL501 to LAG-3 and PD-L1 promotes dendritic cell (DC) activation and tumor cell conjugation with T cells that subsequently mounts effective CD8+ T cell responses. ABL501 demonstrates its potent in vivo antitumor efficacy in a humanized xenograft model and with knockin mice expressing human orthologs. The immune profiling analysis of peripheral blood reveals an increased abundance of LAG-3hiPD-1hi memory CD4+ T cell subset in relapsed cholangiocarcinoma patients after gemcitabine plus cisplatin therapy, which are more responsive to ABL501. This study supports the clinical evaluation of ABL501 as a novel cancer immunotherapeutic, and a first-in-human trial has started (NCT05101109).


Asunto(s)
Anticuerpos Biespecíficos , Antígenos CD , Antígeno B7-H1 , Neoplasias , Animales , Anticuerpos Biespecíficos/farmacología , Anticuerpos Biespecíficos/uso terapéutico , Antígeno B7-H1/metabolismo , Linfocitos T CD8-positivos , Células Dendríticas , Ratones , Neoplasias/tratamiento farmacológico , Receptor de Muerte Celular Programada 1 , Escape del Tumor , Proteína del Gen 3 de Activación de Linfocitos
12.
J Korean Med Sci ; 38(26): e203, 2023 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-37401496

RESUMEN

BACKGROUND: Lead exposure is a known risk factor for cardiovascular disease (CVD), and coronary artery calcification (CAC) is a biomarker for diagnosing atherosclerotic CVD. This study investigated the association between blood lead level (BLL) and CAC using coronary computed tomography (CT) angiography. METHODS: This study enrolled 2,189 participants from the general population with no history or symptoms of CVD. All participants underwent coronary CT angiography, health examination, and BLL testing. The association between coronary artery calcium score (CACS) and BLL was analyzed. RESULTS: The arithmetic mean of BLL was 2.71 ± 1.26 µg/dL, and the geometric mean was 2.42 (1.64) µg/dL, ranging from 0.12 to 10.14 µg/dL. There was a statistically significant positive correlation between CACS and BLL (r = 0.073, P < 0.001). Mean BLLs among predefined CACS categories were as follows: absent grade (CACS = 0), 2.67 ± 1.23 µg/dL; minimal grade (> 0, < 10), 2.81 ± 1.25 µg/dL; mild grade (≥ 10, < 100), 2.74 ± 1.29 µg/dL; moderate grade (≥ 100, < 400), 2.88 ± 1.38 µg/dL; severe grade (≥ 400): 3.22 ± 1.68 µg/dL. The odds ratio for severe CAC was 1.242 in association with an 1 µg/dL increase in BLL (P = 0.042). CONCLUSION: Using coronary CT angiography, we determined a positive correlation between BLL and CAC among participants without CVD from the general population. To reduce the burden of CVD, efforts and policies should be geared toward minimizing environmental lead exposure.


Asunto(s)
Enfermedades Cardiovasculares , Enfermedad de la Arteria Coronaria , Humanos , Plomo , Angiografía por Tomografía Computarizada , Calcio , Vasos Coronarios/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Enfermedades Cardiovasculares/complicaciones , Factores de Riesgo , Angiografía , Angiografía Coronaria/métodos
13.
J Clin Nurs ; 32(15-16): 5328-5356, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36424691

RESUMEN

AIMS AND OBJECTIVES: To determine the effectiveness of nurse-led interventions on medication adherence, medication knowledge and clinical outcomes in adults taking medication for metabolic syndrome. BACKGROUND: Despite the significance of interventions designed to improve medication adherence, a systematic review of nurse-led intervention studies for metabolic syndrome is lacking. DESIGN: A systematic review and meta-analysis of randomised controlled trials. METHODS: The study was conducted following the PRISMA guidelines checklist. PubMed, EMBASE, PsychINFO, CINAHL, Cochrane CENTRAL and other manual sources were searched in May 2021.The quality assessment was conducted using the Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies. Comprehensive Meta-Analysis 3.0 was used to calculate the pooled effect sizes with 95% confidence intervals. RESULTS: This review included 20 studies of nurse-led medication adherence interventions in 6017 adults at risk for metabolic syndrome. The pooled effect size using the random effects model indicated that nurse-led interventions had a significantly moderate impact on enhancing medication adherence and medication knowledge and improving selected clinical outcomes of available studies in nurse-led intervention groups compared with control groups. Duration of intervention (median 12 weeks), mode of delivery (group vs. individual) and using multiple strategies influenced outcomes of nurse-led medication adherence interventions. The results revealed that interventions of moderate- to high-quality studies were more likely to show significant improvements in medication adherence than those of low-quality studies. CONCLUSION: The meta-analyses showed that nurse-led interventions may enhance medication adherence and knowledge and improve clinical outcomes of this population. RELEVANCE TO CLINICAL PRACTICE: The findings may contribute to evidence-based information about nurse-led intervention and its selection of appropriate interventions for improving medication adherence in this population. PATIENT OR PUBLIC CONTRIBUTION: Patients or the public were not directly involved in this review.


Asunto(s)
Síndrome Metabólico , Humanos , Adulto , Síndrome Metabólico/tratamiento farmacológico , Rol de la Enfermera , Preparaciones Farmacéuticas , Cumplimiento de la Medicación
14.
J Cell Mol Med ; 26(7): 2104-2118, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35178859

RESUMEN

Damage to normal tissue can occur over a long period after cancer radiotherapy. Free radical by radiation can initiate or accelerate chronic inflammation, which can lead to atherosclerosis. However, the underlying mechanisms remain unclear. Vascular smooth muscle cells (VSMCs) proliferate in response to JAK/STAT3 signalling. C-reactive protein (CRP) can induce VSMCs apoptosis via triggering NADPH oxidase (NOX). Apoptotic VSMCs promote instability and inflammation of atherosclerotic lesions. Herein, we identified a VSMCs that switched from proliferation to apoptosis through was enhanced by radiation-induced CRP. NOX inhibition using lentiviral sh-p22phox prevented apoptosis upon radiation-induced CRP. CRP overexpression reduced the amount of STAT3/Ref-1 complex, decreased JAK/STAT phosphorylation and formed a new complex of Ref-1/CRP in VSMC. Apoptosis of VSMCs was further increased by CRP co-overexpressed with Ref-1. Functional inhibition of NOX or p53 also prevented apoptotic activity of the CRP-Ref-1 complex. Immunofluorescence showed co-localization of CRP, Ref-1 and p53 with α-actin-positive VSMC in human atherosclerotic plaques. In conclusion, radiation-induced CRP increased the VSMCs apoptosis through Ref-1, which dissociated the STAT3/Ref-1 complex, interfered with JAK/STAT3 activity, and interacted with CRP-Ref-1, thus resulting in transcription-independent cell death via p53. Targeting CRP as a vascular side effect of radiotherapy could be exploited to improve curability.


Asunto(s)
Proteína C-Reactiva , Músculo Liso Vascular , Apoptosis , Proteína C-Reactiva/genética , Proteína C-Reactiva/metabolismo , Células Cultivadas , Humanos , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Factor de Transcripción STAT3/metabolismo
15.
J Biol Chem ; 297(4): 101143, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34473996

RESUMEN

Nitroreductases are emerging as attractive bioremediation enzymes, with substrate promiscuity toward both natural and synthetic compounds. Recently, the nitroreductase NfnB from Sphingopyxis sp. strain HMH exhibited metabolic activity for dinitroaniline herbicides including butralin and pendimethalin, triggering the initial steps of their degradation and detoxification. However, the determinants of the specificity of NfnB for these herbicides are unknown. In this study, we performed structural and biochemical analyses of NfnB to decipher its substrate specificity. The homodimer NfnB is a member of the PnbA subgroup of the nitroreductase family. Each monomer displays a central α + ß fold for the core domain, with a protruding middle region and an extended C-terminal region. The protruding middle region of Val75-Tyr129 represents a structural extension that is a common feature to members of the PnbA subgroup and functions as an opening wall connecting the coenzyme FMN-binding site to the surface, therefore serving as a substrate binding site. We performed mutational, kinetic, and structural analyses of mutant enzymes and found that Tyr88 in the middle region plays a pivotal role in substrate specificity by determining the dimensions of the wall opening. The mutation of Tyr88 to phenylalanine or alanine caused significant changes in substrate selectivity toward bulkier dinitroaniline herbicides such as oryzalin and isopropalin without compromising its activity. These results provide a framework to modify the substrate specificity of nitroreductase in the PnbA subgroup, which has been a challenging issue for its biotechnological and bioremediation applications.


Asunto(s)
Compuestos de Anilina/química , Dinitrobencenos/química , Herbicidas/química , Nitrorreductasas/química , Sphingomonadaceae/enzimología , Sulfanilamidas/química , Sitios de Unión , Relación Estructura-Actividad , Especificidad por Sustrato
16.
Nature ; 534(7605): 129-32, 2016 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-27251290

RESUMEN

The epidermal growth factor receptor (EGFR)-directed tyrosine kinase inhibitors (TKIs) gefitinib, erlotinib and afatinib are approved treatments for non-small cell lung cancers harbouring activating mutations in the EGFR kinase, but resistance arises rapidly, most frequently owing to the secondary T790M mutation within the ATP site of the receptor. Recently developed mutant-selective irreversible inhibitors are highly active against the T790M mutant, but their efficacy can be compromised by acquired mutation of C797, the cysteine residue with which they form a key covalent bond. All current EGFR TKIs target the ATP-site of the kinase, highlighting the need for therapeutic agents with alternative mechanisms of action. Here we describe the rational discovery of EAI045, an allosteric inhibitor that targets selected drug-resistant EGFR mutants but spares the wild-type receptor. The crystal structure shows that the compound binds an allosteric site created by the displacement of the regulatory C-helix in an inactive conformation of the kinase. The compound inhibits L858R/T790M-mutant EGFR with low-nanomolar potency in biochemical assays. However, as a single agent it is not effective in blocking EGFR-driven proliferation in cells owing to differential potency on the two subunits of the dimeric receptor, which interact in an asymmetric manner in the active state. We observe marked synergy of EAI045 with cetuximab, an antibody therapeutic that blocks EGFR dimerization, rendering the kinase uniformly susceptible to the allosteric agent. EAI045 in combination with cetuximab is effective in mouse models of lung cancer driven by EGFR(L858R/T790M) and by EGFR(L858R/T790M/C797S), a mutant that is resistant to all currently available EGFR TKIs. More generally, our findings illustrate the utility of purposefully targeting allosteric sites to obtain mutant-selective inhibitors.


Asunto(s)
Antineoplásicos/farmacología , Bencenoacetamidas/farmacología , Resistencia a Antineoplásicos/genética , Receptores ErbB/genética , Proteínas Mutantes/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Tiazoles/farmacología , Regulación Alostérica/efectos de los fármacos , Sitio Alostérico/efectos de los fármacos , Animales , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/enzimología , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cetuximab/farmacología , Modelos Animales de Enfermedad , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Múltiples Medicamentos/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Sinergismo Farmacológico , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/química , Receptores ErbB/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/enzimología , Neoplasias Pulmonares/patología , Ratones , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Conformación Proteica/efectos de los fármacos , Multimerización de Proteína/efectos de los fármacos
17.
Ecotoxicol Environ Saf ; 243: 113988, 2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-36029578

RESUMEN

Dermal & inhalation exposure was examined and according to these results, risk assessment of agricultural workers to thiamethoxam was performed during pesticide mixing/loading and hand-held sprayer application (11 replicates, each of about 1000 L of spray suspension) in vineyards. For the whole body dosimetry (WBD), clothing (Outer and inner), gauze, and nitrile gloves were analyzed to determine dermal exposure using whole-body dosimetry exposure protocol. The inhalation exposure was measured using a glass fiber filter with an IOM sampler. Analytical method validation of exposure matrices was evaluated including the field recovery and breakthrough test. The dermal exposure amount during mixing/loading was 0.163 mg (0.0004% of the total mixed/loaded active ingredient [a.i.]), whereas there was no inhalation exposure. The gloves (0.154 mg, 94.5%) were the most exposed body parts followed by the chest and stomach (0.009 mg, 5.5%). During application, the dermal and inhalation exposure amounts were 32.3 mg (0.07% of the total applied a.i.) and 10.8 µg (2.4 × 10-6% of the total applied a.i), respectively. The shin (35.1%) had the highest exposure to pesticides, followed by the chest & stomach (15.6%) and pelvis (12.6%). In case of mixing/loading, the amounts of actual dermal exposure (ADE) and actual inhalation exposure (AIE) were 0.0 and 0.0 µg/day, while those of ADE and AIE were 4707.6 and 15.8 µg/day for application. In risk assessment of the two different scenarios, the risk index was much lower than 1 (mixing/loading:0.000, application:0.014), indicating that vineyard workers are at low risk of thiamethoxam exposure. To determine the validity of the risk assessment using WBD method, the urinary metabolite was analyzed. Comparison of biomonitoring data and WBD exposure data show a reliable correlation (r = 0.885, p = 0.0003), suggesting that these are suitable methods to estimate exposure.


Asunto(s)
Exposición Profesional , Plaguicidas , Agricultores , Granjas , Humanos , Exposición Profesional/análisis , Medición de Riesgo , Tiametoxam
18.
Molecules ; 27(23)2022 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-36500220

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) has one of the highest mortality rates and requires the development of highly efficacious medications that can improve the efficiency of existing treatment methods. In particular, in PDAC, resistance to conventional chemotherapy reduces the effectiveness of anticancer drugs, decreasing the therapeutic efficiency. Sphingosine 1-phosphate (S1P), produced by sphingosine kinase (SK), plays a vital role in cancer growth, metastasis, chemotherapy, and drug resistance. Focusing on the structural characteristics of mebendazole (MBZ), we studied whether MBZ would affect metastasis, invasion, and drug resistance in cancer by lowering S1P production through inhibition of SK activity. MBZ selectively inhibited SK1 more than SK2 and regulated the levels of sphingolipids. MBZ inhibited the proliferation and migration of cancer cells in other PDAC cell lines. To determine whether the effect of MBZ on cancer cell growth and migration is S1P-mediated, S1P was treated, and the growth and migration of cancer cells were observed. It was found that MBZ inhibited S1P-induced cancer cell growth, and MBZ showed a growth inhibitory effect by regulating the JAK2/STAT3/Bcl-2 pathway. The phosphorylation of focal adhesion kinase (FAK), a transcription factor that regulates migration, was inhibited by MBZ, so it was found that the effect of MBZ regulates the migration of cancer cells through the S1P/FAK/vimentin pathway. In conclusion, our study suggests that the anthelmintic MBZ can be used as a potential therapeutic agent for treating PDAC and for structural synthesis studies of its analogs.


Asunto(s)
Lisofosfolípidos , Neoplasias Pancreáticas , Humanos , Lisofosfolípidos/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Esfingosina , Mebendazol/farmacología , Neoplasias Pancreáticas/tratamiento farmacológico , Proliferación Celular , Neoplasias Pancreáticas
19.
Molecules ; 27(10)2022 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-35630821

RESUMEN

Sphingosine kinase (SK) is involved in the growth of cells, including cancer cells. However, which of its two isotypes-SK1 and SK2-is more favorable for cancer growth remains unclear. Although PF-543 strongly and selectively inhibits SK1, its anticancer effect is not high, and the underlying reason remains difficult to explain. We previously determined that the tail group of PF-543 is responsible for its low metabolic stability (MS). In this study, compounds containing aromatic or aliphatic tails in the triazole group were synthesized, and changes in the SK-inhibitory effect and anticancer activity of PF-543 were assessed using pancreatic cancer cells. The compounds with aliphatic tails showed high inhibitory effects on pancreatic cancer cells but slightly lower selectivity for SK1. A compound with an introduced aliphatic tail activated protein phosphatase 2A (PP2A), showing an effect similar to that of FTY720. Molecular docking analysis revealed that the PP2A-binding form of this newly synthesized compound was different from that noted in the case of FTY720. This compound also improved the MS of PF-543. These results indicate that the tail structure of PF-543 influences MS.


Asunto(s)
Neoplasias Pancreáticas , Proteína Fosfatasa 2 , Clorhidrato de Fingolimod/farmacología , Humanos , Metanol , Simulación del Acoplamiento Molecular , Neoplasias Pancreáticas/tratamiento farmacológico , Pirrolidinas , Sulfonas
20.
J Appl Res Intellect Disabil ; 35(1): 271-279, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34658098

RESUMEN

BACKGROUND: Studies have reported difficulties in job acquisition and retention as well as unstable employment status among individuals with intellectual disabilities. METHOD: Chi-square, one-way ANOVA, and binary logistic regression analysis were employed to investigate the factors that affect the labour market transition of 374 individuals with intellectual disabilities. RESULTS: There were significant differences in sex between the sustained unemployment group and the sustained employment groups; in educational level, between sustained employment and other groups; and in basic living security assistance received, between sustained unemployment and other groups. All psychological factors in the sustained employment group were higher than in the sustained unemployment group. Communication ability significantly affected sustained employment. CONCLUSIONS: Greater family support was associated with a lower turnover probability, and a higher educational level and greater family support increased the probability of retention. Developing family support systems may decrease the possibility of turnover and increase retention.


Asunto(s)
Discapacidad Intelectual , Desempleo , Escolaridad , Empleo , Humanos
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