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1.
J Obstet Gynaecol Can ; 45(8): 581-586, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37271344

RESUMEN

We describe the disability-related education and training experiences of perinatal care providers in Ontario. Twenty perinatal care providers (e.g., obstetricians, midwives) participated in semi-structured interviews. Using a content analysis approach, we found most acquired disability-related training through their own initiative as opposed to education through professional training programs. Barriers to training included lack of data on disability and pregnancy and limited experiential learning opportunities. Providers recommended that future training focus on experiential learning and social determinants of health, with people with disabilities involved in developing and delivering training. These efforts are vital to optimize pregnancy outcomes for people with disabilities.


Asunto(s)
Partería , Atención Perinatal , Embarazo , Femenino , Recién Nacido , Niño , Humanos , Ontario , Investigación Cualitativa , Resultado del Embarazo
2.
Burns ; 49(6): 1403-1411, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-36878736

RESUMEN

BACKGROUND: Several studies demonstrated that burn size calculations by referring clinicians are poor. The purpose of this study was to determine if inaccuracies in burn size estimation have improved with time within the same population, and whether widespread roll-out of a smartphone-based TBSA calculator (in the form of the NSW Trauma App) had an impact on accuracy. METHODS: A review of all burn-injured adult patients transferred to Burn Units from August 2015, following the roll out of the NSW Trauma App, to January 2021 was performed. The TBSA determined by the referring centre was compared with the TBSA calculated by the Burn Unit. This was compared to historical data from the same population between January 2009 and August 2013. RESULTS: There were 767 adult burn-injured patients transferred to a Burn Unit between 2015 and 2021. The median overall TBSA was 7%. There were 290 patients (37.9%) who had equivalent TBSA calculations by the referring hospital and the Burn Unit. This was a significant improvement compared to the preceding time period (P < 0.005). Overestimation by the referring hospital occurred in 364 cases (47.5%), which was significantly reduced compared to 2009 - 2013 (P < 0.001). Unlike the earlier time period where changes in estimation accuracy were seen in relation to increasing time after the burn injury, burn size estimation accuracy remained relatively consistent in the contemporary time period with no significant change observed (P = 0.86). CONCLUSIONS: This cumulative, longitudinal study of nearly 1500 adult burn-injured patients over 13 years demonstrates improvements in burn size estimation by referring clinicians over time. It is the largest cohort of patients analysed with respect to burn size estimation and is the first to demonstrate improvements in accuracy of TBSA in association with a smartphone-based app. Adopting this simple strategy into burn retrieval systems will augment early assessment of these injuries and improve outcomes.


Asunto(s)
Quemaduras , Aplicaciones Móviles , Adulto , Humanos , Estudios Longitudinales , Superficie Corporal , Puntaje de Gravedad del Traumatismo , Unidades de Quemados , Estudios Retrospectivos
3.
J Adv Nurs ; 79(9): 3324-3336, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36932042

RESUMEN

AIM: To understand the postpartum care received by birthing people with disabilities and their newborns, from their own perspectives. DESIGN: A qualitative study with semi-structured interviews. METHODS: Between July 2019 and February 2020, in-person and virtual interviews were conducted with 31 people with physical, sensory, and intellectual/developmental disabilities in Ontario, Canada, about the formal inpatient and outpatient services and supports they used in the first few months after they gave birth. Thematic analysis was used identify common themes. RESULTS: We identified three overall themes concerning participants' postpartum care experiences and the different types of formal services received in and out of hospital: (1) lack of adequate care, (2) lack of provider awareness of disability and disability accommodations, and (3) fear of judgement, discrimination, and intrusive surveillance. The identified themes were applicable across disability groups. However, most comments on disability accommodations came from participants with physical or sensory disabilities, while participants with intellectual/developmental disabilities most commonly reported concerns about lack of adequate care and fear of judgement, discrimination, and intrusive surveillance. CONCLUSION: Findings indicate that postpartum care often fails people with disabilities. This could contribute to negative health consequences for them and their newborns. IMPACT: Birthing people with disabilities need multidisciplinary, proactive, and strengths-based postpartum care to mitigate risk for health complications. Further, disability-related training and guidelines for health and social service providers is required. REPORTING METHOD: Consolidated criteria for reporting qualitative research (COREQ). PATIENT OR PUBLIC CONTRIBUTION: Our research team included two peer researchers with physical disabilities who served as co-interviewers and participated in data analysis, contributing their lived experience of disability and interactions with the health care system. All stages of the study were also informed by feedback from the study's Advisory Committee, which comprised women with disabilities (many of whom are parents), disability organization staff, clinicians, and policy representatives.


Asunto(s)
Personas con Discapacidad , Discapacidad Intelectual , Recién Nacido , Humanos , Femenino , Atención a la Salud , Periodo Posparto , Ontario , Investigación Cualitativa
4.
J Obstet Gynecol Neonatal Nurs ; 52(3): 235-247, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36940781

RESUMEN

OBJECTIVE: To explore the care experiences of childbearing people with physical, sensory, and/or intellectual/developmental disabilities during pregnancy. DESIGN: Descriptive qualitative. SETTING: Ontario, Canada, where physician and midwifery care during pregnancy are provided at no direct cost to residents. PARTICIPANTS: Thirty-one people with physical, sensory, and/or intellectual/developmental disabilities (who self-identified as cisgender women [n = 29] and trans or nonbinary persons [n = 2]) who gave birth in the last 5 years. METHODS: We recruited childbearing people with disabilities through disability and parenting organizations, social media, and our team's networks. Using a semistructured guide, we conducted in-person and virtual (e.g., telephone or Zoom) interviews with childbearing people with disabilities in 2019 to 2020. We asked participants about the services they accessed during pregnancy and if services met their needs. We used a reflexive thematic analysis approach to analyze interview data. RESULTS: Across disability groups, we identified four common themes: Unmet Accommodation Needs, Lack of Coordinated Care, Ableism, and Advocacy as a Critical Resource. We found that these experiences manifested in unique ways based on disability type. CONCLUSION: Our findings suggest the need for accessible, coordinated, and respectful prenatal care for people with disabilities, with the requirements of such care depending on the needs of the individual person with a disability. Nurses can play a key role in identifying the needs and supporting people with disabilities during pregnancy. Education and training for nurses, midwives, obstetricians, and other prenatal care providers should focus on disability-related knowledge and respectful prenatal care.


Asunto(s)
Personas con Discapacidad , Partería , Embarazo , Femenino , Humanos , Atención Prenatal , Ontario , Parto , Investigación Cualitativa
5.
Burns ; 49(4): 961-972, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-35728985

RESUMEN

INTRODUCTION: Modern burn care is centralised, and studies show that early, prompt referral to dedicated burn services improve clinical outcomes. We describe the use of a novel clinical instrument, the burn injury Transfer Feedback Form, to support and educate referring clinicians about the early assessment and management of burn injuries. Since 2005, Transfer Feedback Forms have been completed for all burn-injured patients with inter-hospital transfer to a specialised burn unit in the state of New South Wales (NSW), Australia. The aim of this study was to review physiological, procedural, and system or process issues in the care of both adult and paediatric burn-injured patients needing retrieval and transfer in NSW as identified by the Transfer Feedback Form. Secondary objectives were to determine any significant differences in these parameters between metropolitan and regional or remote referring institutions, and if any improvements occurred in these parameters over time. METHODS: This was a retrospective analysis of all patients who were transferred to a burn unit in NSW between July 2005 and July 2021 using their prospectively completed Transfer Feedback Forms. Patients were divided into metropolitan and non-metropolitan referral sources based on geographic location. Clinical issues or deficiencies identified during each patient transfer were then classified into various groups. To determine if transfer-related clinical concerns had changed with time, two distinct periods before and after 2015, when the NSW Trauma App was introduced, were analysed. We compared trends in frequency of transfer-related concerns before and after App introduction by using interrupted time series analysis. RESULTS: A total of 3233 patients had Feedback Forms submitted during the 16-year period. We included 929 children (28.7%) and 2304 adults (71.3%). Transfer-related clinical issues were identified in 904 adults (39.0%) and 484 children (52.0%). In both adult and paediatric patients, the most common transfer-related clinical deficiency was in relation to burn size estimation with 525 patients (43.7%) and 207 patients (30.6%), respectively. Between the time periods analysed, the number of issues arising during inter-hospital transfer fell significantly for both adults (from 46.1% to 26.1%; p < 0.05) and children (from 55.3% to 40.7%; p < 0.05). Segmented regression analysis demonstrated a significant break in the rate of transfer-related clinical issues in 2014 (p < 0.05) and 2015 (p < 0.01) for adults. Accurate body surface area estimations also increased significantly by 53% and 50% for adults and children (p < 0.05 for both), respectively, after 2015. CONCLUSION: Our analysis indicates that the early care of burn-injured patients undergoing inter-hospital transfer is associated with clinical, technical, and logistical challenges. However, introduction of the burn injury Transfer Feedback Form has been associated with improvements in early burn care by referring centres both temporally and geographically. Smartphone-based applications such as the NSW Trauma App have also probably contributed to these findings. Adopting these simple, inexpensive strategies into burn care systems will augment inter-hospital transfer of burn-injured patients, and improve clinical outcomes.


Asunto(s)
Quemaduras , Transferencia de Pacientes , Adulto , Niño , Humanos , Australia , Retroalimentación , Hospitales , Estudios Retrospectivos
6.
BMC Pregnancy Childbirth ; 22(1): 364, 2022 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35473673

RESUMEN

BACKGROUND: Effective provider-patient communication is a key element of quality health care, including perinatal care. What constitutes "effective communication" in perinatal care may vary according to the population seeking care, such as women with intellectual and developmental disabilities (IDD) and sensory disabilities. Research broadly indicates that communication issues are among the barriers to perinatal care experienced by women with disabilities. However, few studies have explicitly explored their communication experiences in this context. The purpose of this study was to understand the communication experiences of birthing people with IDD and/or sensory disabilities in perinatal care. METHODS: We conducted semi-structured interviews with 17 people with IDD (e.g., autism, cognitive delay) and/or sensory disabilities (e.g., d/Deaf, blind) in Ontario, Canada, who had recently given birth, to explore barriers to and facilitators of effective communication in perinatal care. A combination of deductive and inductive thematic analysis guided data analysis. RESULTS: We found that birthing people with IDD and/or sensory disabilities encountered multiple barriers to effective communication in perinatal care, namely, lack of policies and guidelines, lack of provider experience, lack of provider effort, as well as ableism and provider assumptions. Facilitators included knowledgeable, aware, and supportive providers; access to communication aids and services; tailoring information to patients' disability-related communication needs; empathic communication; and, communication among providers. CONCLUSION: Unmet communication needs may contribute to negative health and social outcomes for birthing people with disabilities and their newborns. Accessibility policy implementation and practice change are needed to meet the communication needs of people with IDD and/or sensory disabilities in perinatal care to ensure positive experiences and outcomes.


Asunto(s)
Discapacidades del Desarrollo , Atención Perinatal , Niño , Comunicación , Discapacidades del Desarrollo/terapia , Femenino , Accesibilidad a los Servicios de Salud , Humanos , Recién Nacido , Ontario , Embarazo
7.
Womens Health Issues ; 31(6): 550-559, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34556400

RESUMEN

BACKGROUND: Accessible and quality care during the perinatal period is critical for optimal maternal and neonatal health. Using the socio-ecological model, the purpose of this study was to explore barriers and facilitators that shape the perinatal care experiences of people with intellectual and/or developmental disabilities (IDD). METHODS: Semi-structured interviews were conducted with 10 individuals with IDD in Ontario, Canada, who had given birth within the past 5 years. Interviews focused on care experiences before, during, and after pregnancy. Data were analyzed using a directed content analysis approach, and the socio-ecological model guided analysis. RESULTS: Barriers at the societal (e.g., cultural norms of motherhood), policy/institutional (e.g., child protection policies and practices), interpersonal (e.g., inadequate formal and informal support), and intrapersonal levels (e.g., internalized stigma) contributed to participants having negative perinatal care experiences. Conversely, we identified facilitators on the interpersonal level (e.g., positive interactions with perinatal care providers and familial and social service supports) as positively shaping participants' perinatal care experiences. CONCLUSIONS: Findings reveal that the perinatal care experiences of people with IDD are shaped by several interrelated factors that largely stem from societal-level barriers, such as dominant (stigmatizing) discourses of disability. To improve the perinatal care experiences of people with IDD, there is a need for interventions at multiple levels. These include the development of policies to support perinatal care for diverse populations and training care providers to enact policies at the institutional and interpersonal levels.


Asunto(s)
Personas con Discapacidad , Atención Perinatal , Discapacidades del Desarrollo , Femenino , Humanos , Recién Nacido , Ontario , Parto , Embarazo
8.
PLoS One ; 11(9): e0161952, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27617834

RESUMEN

Members of the Inhibitor of APoptosis (IAP) protein family suppress apoptosis within tumor cells, particularly in the context of immune cell-mediated killing by the tumor necrosis factor (TNF) superfamily cytokines. Most IAPs are opposed endogenously by the second mitochondrial activator of caspases (SMAC), which binds to selected baculovirus IAP repeat (BIR) domains of IAPs to displace interacting proteins. The development of SMAC mimetics as novel anticancer drugs has gained impetus, with several agents now in human clinical trials. To further understand the cellular mechanisms of SMAC mimetics, we focused on IAP family members cIAP1 and cIAP2, which are recruited to TNF receptor complexes where they support cell survival through NF-κB activation while suppressing apoptosis by preventing caspase activation. We established fluorescence polarization (FP) assays for the BIR2 and BIR3 domains of human cIAP1 and cIAP2 using fluorochrome-conjugated SMAC peptides as ligands. A library of SMAC mimetics was profiled using the FP assays to provide a unique structure activity relationship (SAR) analysis compared to previous assessments of binding to XIAP. Potent compounds displayed mean inhibitory binding constants (Ki) of 9 to 27 nM against the BIR3 domains of cIAP1 and cIAP2, respectively. Selected compounds were then characterized using cytotoxicity assays in which a cytokine-resistant human tumor cell line was sensitized to either TNF or lymphotoxin-α (LT-α). Cytotoxicity correlated closely with cIAP1 and cIAP2 BIR3 binding activity with the most potent compounds able to reduce cell viability by 50%. Further testing demonstrated that active compounds also inhibit RIP1 binding to BIR3 of cIAP1 and cIAP2 in vitro and reduce steady-state cIAP1 protein levels in cells. Altogether, these data inform the SAR for our SMAC mimetics with respect to cIAP1 and cIAP2, suggesting that these IAP family members play an important role in tumor cell resistance to cytotoxicity mediated by TNF and LT-α.


Asunto(s)
Apoptosis/fisiología , Proteínas Inhibidoras de la Apoptosis/fisiología , Péptidos y Proteínas de Señalización Intracelular/fisiología , Proteínas Mitocondriales/fisiología , Imitación Molecular , Factor de Necrosis Tumoral alfa/fisiología , Proteínas Reguladoras de la Apoptosis , Línea Celular Tumoral , Polarización de Fluorescencia , Humanos , Proteínas Inhibidoras de la Apoptosis/metabolismo , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Mitocondriales/química , Proteínas Mitocondriales/metabolismo , Unión Proteica
9.
J Biomol Screen ; 19(8): 1201-11, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24870016

RESUMEN

Antiapoptotic Bcl-2 family proteins are validated cancer targets composed of six related proteins. From a drug discovery perspective, these are challenging targets that exert their cellular functions through protein-protein interactions (PPIs). Although several isoform-selective inhibitors have been developed using structure-based design or high-throughput screening (HTS) of synthetic chemical libraries, no large-scale screen of natural product collections has been reported. A competitive displacement fluorescence polarization (FP) screen of nearly 150,000 natural product extracts was conducted against all six antiapoptotic Bcl-2 family proteins using fluorochrome-conjugated peptide ligands that mimic functionally relevant PPIs. The screens were conducted in 1536-well format and displayed satisfactory overall HTS statistics, with Z'-factor values ranging from 0.72 to 0.83 and a hit confirmation rate between 16% and 64%. Confirmed active extracts were orthogonally tested in a luminescent assay for caspase-3/7 activation in tumor cells. Active extracts were resupplied, and effort toward the isolation of pure active components was initiated through iterative bioassay-guided fractionation. Several previously described altertoxins were isolated from a microbial source, and the pure compounds demonstrate activity in both Bcl-2 FP and caspase cellular assays. The studies demonstrate the feasibility of ultra-high-throughput screening using natural product sources and highlight some of the challenges associated with this approach.


Asunto(s)
Productos Biológicos/química , Ensayos Analíticos de Alto Rendimiento/métodos , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Células CACO-2 , Caspasa 3/metabolismo , Caspasa 7/metabolismo , Ensayos de Selección de Medicamentos Antitumorales/métodos , Polarización de Fluorescencia/métodos , Ensayos Analíticos de Alto Rendimiento/instrumentación , Humanos , Miniaturización , Terapia Molecular Dirigida/métodos , Micotoxinas/aislamiento & purificación , Micotoxinas/farmacología , Extracción en Fase Sólida , Proteína bcl-X/antagonistas & inhibidores
10.
Mol Cancer Ther ; 13(1): 5-15, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24194568

RESUMEN

TNF-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent because it shows apoptosis-inducing activity in transformed, but not in normal, cells. As with most anticancer agents, however, its clinical use is restricted by either inherent or acquired resistance by cancer cells. We demonstrate here that small-molecule SMAC mimetics that antagonize the inhibitor of apoptosis proteins (IAP) potently sensitize previously resistant human cancer cell lines, but not normal cells, to TRAIL-induced apoptosis, and that they do so in a caspase-8-dependent manner. We further show that the compounds have no cytotoxicity as single agents. Also, we demonstrate that several IAP family members likely participate in the modulation of cellular sensitivity to TRAIL. Finally, we note that the compounds that sensitize cancer cells to TRAIL are the most efficacious in binding to X-linked IAP, and in inducing cellular-IAP (cIAP)-1 and cIAP-2 degradation. Our studies thus describe valuable compounds that allow elucidation of the signaling events occurring in TRAIL resistance, and demonstrate that these agents act as potent TRAIL-sensitizing agents in a variety of cancer cell lines.


Asunto(s)
Proteínas Inhibidoras de la Apoptosis/metabolismo , Neoplasias/genética , Ligando Inductor de Apoptosis Relacionado con TNF/genética , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Proteína 3 que Contiene Repeticiones IAP de Baculovirus , Caspasa 8/genética , Caspasa 8/metabolismo , Línea Celular Tumoral , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Humanos , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Terapia Molecular Dirigida , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Transducción de Señal/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/administración & dosificación , Ligando Inductor de Apoptosis Relacionado con TNF/administración & dosificación , Ubiquitina-Proteína Ligasas , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores
11.
Bioorg Med Chem Lett ; 23(14): 4253-7, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23743278

RESUMEN

We recently reported the systematic ligand-based rational design and synthesis of monovalent Smac mimetics that bind preferentially to the BIR2 domain of the anti-apoptotic protein XIAP. Expanded structure-activity relationship (SAR) studies around these peptidomimetics led to compounds with significantly improved selectivity (>60-fold) for the BIR2 domain versus the BIR3 domain of XIAP. The potent and highly selective IAP antagonist 8q (ML183) sensitized TRAIL-resistant prostate cancer cells to apoptotic cell death, highlighting the merit of this probe compound as a valuable tool to investigate the biology of XIAP.


Asunto(s)
Materiales Biomiméticos/síntesis química , Diseño de Fármacos , Oligopéptidos/síntesis química , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores , Sitios de Unión , Materiales Biomiméticos/química , Materiales Biomiméticos/toxicidad , Línea Celular Tumoral , Supervivencia Celular , Resistencia a Antineoplásicos/efectos de los fármacos , Humanos , Simulación del Acoplamiento Molecular , Oligopéptidos/química , Oligopéptidos/toxicidad , Unión Proteica , Estructura Terciaria de Proteína , Relación Estructura-Actividad , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo
12.
ACS Chem Biol ; 8(4): 725-32, 2013 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-23323685

RESUMEN

A series of novel, potent antagonists of the inhibitor of apoptosis proteins (IAPs) were synthesized in a highly convergent and rapid fashion (≤6 steps) using the Ugi four-component reaction as the key step, thus enabling rapid optimization of binding potency. These IAP antagonists compete with caspases 3, 7, and 9 for inhibition by X chromosome-linked IAP (XIAP) and bind strongly (nanomolar binding constants) to several crucial members of the IAP family of cancer pro-survival proteins to promote apoptosis, with a particularly unique selectivity for melanoma IAP (ML-IAP). Experiments in cell culture revealed powerful cancer cell growth inhibitory activity in multiple (breast, ovarian, and prostate) cell lines with single agent toxicity at low nanomolar levels against SKOV-3 human ovarian carcinoma cells. Administration of the compounds to human foreskin fibroblast cells revealed no general toxicity to normal cells. Furthermore, computational modeling was performed, revealing key contacts between the IAP proteins and antagonists, suggesting a structural basis for the observed potency.


Asunto(s)
Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Melanoma/metabolismo , Inhibidores de Caspasas/farmacología , Diseño de Fármacos , Polarización de Fluorescencia , Proteínas Inhibidoras de la Apoptosis/metabolismo , Modelos Moleculares
13.
J Biomol Screen ; 17(2): 163-76, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22034497

RESUMEN

UBC13 is a noncanonical ubiquitin conjugating enzyme (E2) that has been implicated in a variety of cellular signaling processes due to its ability to catalyze formation of lysine 63-linked polyubiquitin chains on various substrates. In particular, UBC13 is required for signaling by a variety of receptors important in immune regulation, making it a candidate target for inflammatory diseases. UBC13 is also critical for double-strand DNA repair and thus a potential radiosensitizer and chemosensitizer target for oncology. The authors developed a high-throughput screening (HTS) assay for UBC13 based on the method of time-resolved fluorescence resonance energy transfer (TR-FRET). The TR-FRET assay combines fluorochrome (Fl)-conjugated ubiquitin (fluorescence acceptor) with terbium (Tb)-conjugated ubiquitin (fluorescence donor), such that the assembly of mixed chains of Fl- and Tb-ubiquitin creates a robust TR-FRET signal. The authors defined conditions for optimized performance of the TR-FRET assay in both 384- and 1536-well formats. Chemical library screens (total 456 865 compounds) were conducted in high-throughput mode using various compound collections, affording superb Z' scores (typically >0.7) and thus validating the performance of the assays. Altogether, the HTS assays described here are suitable for large-scale, automated screening of chemical libraries in search of compounds with inhibitory activity against UBC13.


Asunto(s)
Ensayos Analíticos de Alto Rendimiento/métodos , Poliubiquitina/biosíntesis , Enzimas Ubiquitina-Conjugadoras/antagonistas & inhibidores , Transferencia Resonante de Energía de Fluorescencia/métodos , Poliubiquitina/química , Bibliotecas de Moléculas Pequeñas , Ubiquitinación
14.
Bioorg Med Chem Lett ; 21(14): 4332-6, 2011 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-21680182

RESUMEN

We report the systematic rational design and synthesis of new monovalent Smac mimetics that bind preferentially to the BIR2 domain of the anti-apoptotic protein XIAP. Characterization of compounds in vitro (including 9i; ML101) led to the determination of key structural requirements for BIR2 binding affinity. Compounds 9h and 9j sensitized TRAIL-resistant breast cancer cells to apoptotic cell death, highlighting the value of these probe compounds as tools to investigate the biology of XIAP.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/química , Proteínas Mitocondriales/química , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores , Apoptosis , Sitios de Unión , Materiales Biomiméticos/síntesis química , Materiales Biomiméticos/química , Materiales Biomiméticos/farmacología , Línea Celular Tumoral , Simulación por Computador , Diseño de Fármacos , Humanos , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Mitocondriales/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Proteína Inhibidora de la Apoptosis Ligada a X/química , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo
15.
Exp Biol Med (Maywood) ; 236(2): 247-51, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21321323

RESUMEN

We report here a series of new inhibitors of the X-linked inhibitor of apoptosis protein (XIAP protein) based on the SMAC-tetrapeptide AVPI. The structural novelty of these molecules is the presence of the proline mimetic exo-2-azabicyclo[2.2.1]heptane-3-carboxylic acid, leading to analogs with similar activity to the natural ligand peptide. The structure-activity relationship and computational docking studies support the convenience of this unnatural amino acid as a building block to develop new peptides or small molecules targeting the XIAP-BIR3 domain.


Asunto(s)
Apoptosis , Biología Molecular/métodos , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo , Compuestos Bicíclicos con Puentes/metabolismo , Humanos , Modelos Moleculares , Simulación de Dinámica Molecular , Péptidos/química , Péptidos/metabolismo , Prolina/análogos & derivados , Relación Estructura-Actividad
16.
J Biomol Screen ; 16(2): 174-82, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21245471

RESUMEN

Autophagy is an evolutionarily conserved process for catabolizing damaged proteins and organelles in a lysosome-dependent manner. Dysregulation of autophagy may cause various diseases, such as cancer and neurodegeneration. However, the relevance of autophagy to diseases remains controversial because of the limited availability of chemical modulators. Herein, the authors developed a fluorescence-based assay for measuring activity of the autophagy protease, autophagin-1(Atg4B). The assay employs a novel reporter substrate of Atg4B composed of a natural substrate (LC3B) fused to an assayable enzyme (PLA(2)) that becomes active upon cleavage by this cysteine protease. A high-throughput screening (HTS) assay was validated with excellent Z' factor (>0.7), remaining robust for more than 5 h and suitable for screening of large chemical libraries. The HTS assay was validated by performing pilot screens with 2 small collections of compounds enriched in bioactive molecules (n = 1280 for Lopac™ and 2000 for Spectrum™ library), yielding confirmed hit rates of 0.23% and 0.70%, respectively. As counterscreens, PLA(2) and caspase-3 assays were employed to eliminate nonspecific inhibitors. In conclusion, the LC3B-PLA(2) reporter assay provides a platform for compound library screening for identification and characterization of Atg4B-specific inhibitors that may be useful as tools for interrogating the role of autophagy in disease models.


Asunto(s)
Cisteína Endopeptidasas/metabolismo , Inhibidores Enzimáticos/metabolismo , Ensayos Analíticos de Alto Rendimiento , Espectrometría de Fluorescencia , Autofagia , Proteínas Relacionadas con la Autofagia , Caspasa 3/metabolismo , Cisteína Endopeptidasas/genética , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Orden Génico , Humanos , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Bibliotecas de Moléculas Pequeñas
17.
Mol Cell ; 41(1): 107-16, 2011 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-21185211

RESUMEN

ARTS (apoptosis-related protein in the TGF-ß signaling pathway) is a mitochondrial protein that binds XIAP (X-linked inhibitor of apoptosis protein) upon entering the cytosol, thus promoting cell death. Expression of ARTS is lost in some malignancies. Here, we show that ARTS binds to XIAP at BIR1, a domain distinct from the caspase-binding sites. Furthermore, ARTS interacts with the E3 ligase Siah-1 (seven in absentia homolog 1) to induce ubiquitination and degradation of XIAP. Cells lacking either Siah or ARTS contain higher steady-state levels of XIAP. Thus, ARTS serves as an adaptor to bridge Siah-1 to XIAP, targeting it for destruction.


Asunto(s)
Proteínas Nucleares/fisiología , Septinas/fisiología , Ubiquitina-Proteína Ligasas/fisiología , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo , Animales , Apoptosis , Sitios de Unión , Línea Celular , Células HEK293 , Humanos , Ratones , Proteínas Nucleares/metabolismo , Mapeo de Interacción de Proteínas , Septinas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación
18.
J Biol Chem ; 285(8): 5569-80, 2010 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-20022954

RESUMEN

Apoptosis plays important roles in host defense, including the elimination of virus-infected cells. The executioners of apoptosis are caspase family proteases. We report that vaccinia virus-encoded F1L protein, previously recognized as anti-apoptotic viral Bcl-2 family protein, is a caspase-9 inhibitor. F1L binds to and specifically inhibits caspase-9, the apical protease in the mitochondrial cell death pathway while failing to inhibit other caspases. In cells, F1L inhibits apoptosis and proteolytic processing of caspases induced by overexpression of caspase-9 but not caspase-8. An N-terminal region of F1L preceding the Bcl-2-like fold accounts for caspase-9 inhibition and significantly contributes to the anti-apoptotic activity of F1L. Viral F1L thus provides the first example of caspase inhibition by a Bcl-2 family member; it functions both as a suppressor of proapoptotic Bcl-2 family proteins and as an inhibitor of caspase-9, thereby neutralizing two sequential steps in the mitochondrial cell death pathway.


Asunto(s)
Inhibidores de Caspasas , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Virus Vaccinia/metabolismo , Proteínas Virales/metabolismo , Animales , Apoptosis/genética , Caspasa 8/química , Caspasa 8/genética , Caspasa 8/metabolismo , Caspasa 9/química , Caspasa 9/genética , Caspasa 9/metabolismo , Bovinos , Células HeLa , Humanos , Mitocondrias/química , Mitocondrias/genética , Mitocondrias/metabolismo , Unión Proteica/fisiología , Estructura Terciaria de Proteína/genética , Proteínas Proto-Oncogénicas c-bcl-2/química , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Virus Vaccinia/química , Virus Vaccinia/genética , Proteínas Virales/química , Proteínas Virales/genética
19.
Bioorg Med Chem Lett ; 19(22): 6413-8, 2009 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-19819692

RESUMEN

Based on tetrapeptide AVPI, we were able to design and synthesize a new simplified scaffold to inhibit the BIR3 domain of the XIAP protein at low micromolar range. The uncomplicated synthesis and the binding activity of the molecule disclosed here represent an attractive alternative to develop new compounds targeting the protein-protein interaction of XIAP/caspase9.


Asunto(s)
Proteínas Inhibidoras de la Apoptosis , Oligopéptidos/química , Relación Estructura-Actividad , Proteína Inhibidora de la Apoptosis Ligada a X/administración & dosificación , Apoptosis , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Proteínas Mitocondriales , Conformación Proteica , Estructura Terciaria de Proteína , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores
20.
Proc Natl Acad Sci U S A ; 106(34): 14524-9, 2009 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-19667203

RESUMEN

NOD1 and NOD2 are members of the NOD-like receptor (NLR) protein family that are involved in sensing the presence of pathogens and are a component of the innate immune system. Upon activation by specific bacterial peptides derived from peptidoglycans, NODs interact via a CARD-CARD interaction with the receptor-interacting protein kinase RIP2, an inducer of NF-kappaB activation. In this report, we show that NOD signaling is dependent on XIAP, a member of the inhibitor of apoptosis protein (IAP) family. Cells deficient in XIAP exhibit a marked reduction in NF-kappaB activation induced by microbial NOD ligands and by over-expression of NOD1 or NOD2. Moreover, we show that XIAP interacts with RIP2 via its BIR2 domain, which could be disrupted by XIAP antagonists SMAC and SMAC-mimicking compounds. Both NOD1 and NOD2 associated with XIAP in a RIP2-dependent manner, providing evidence that XIAP associates with the NOD signalosome. Taken together, our data suggest a role for XIAP in regulating innate immune responses by interacting with NOD1 and NOD2 through interaction with RIP2.


Asunto(s)
Proteína Adaptadora de Señalización NOD1/metabolismo , Proteína Adaptadora de Señalización NOD2/metabolismo , Proteína Serina-Treonina Quinasa 2 de Interacción con Receptor/metabolismo , Transducción de Señal , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo , Línea Celular , Línea Celular Tumoral , Ensayo de Inmunoadsorción Enzimática , Expresión Génica , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HCT116 , Humanos , Immunoblotting , Inmunoprecipitación , Interleucina-8/metabolismo , Luciferasas/genética , Luciferasas/metabolismo , Mutación , FN-kappa B/genética , FN-kappa B/metabolismo , Proteína Adaptadora de Señalización NOD1/genética , Proteína Adaptadora de Señalización NOD2/genética , Unión Proteica , ARN Interferente Pequeño/genética , Proteína Serina-Treonina Quinasa 2 de Interacción con Receptor/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transfección , Proteína Inhibidora de la Apoptosis Ligada a X/genética
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