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1.
Nat Commun ; 15(1): 3244, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38622111

RESUMEN

Proteins are molecular machines and to understand how they work, we need to understand how they move. New pump-probe time-resolved X-ray diffraction methods open up ways to initiate and observe protein motions with atomistic detail in crystals on biologically relevant timescales. However, practical limitations of these experiments demands parallel development of effective molecular dynamics approaches to accelerate progress and extract meaning. Here, we establish robust and accurate methods for simulating dynamics in protein crystals, a nontrivial process requiring careful attention to equilibration, environmental composition, and choice of force fields. With more than seven milliseconds of sampling of a single chain, we identify critical factors controlling agreement between simulation and experiments and show that simulated motions recapitulate ligand-induced conformational changes. This work enables a virtuous cycle between simulation and experiments for visualizing and understanding the basic functional motions of proteins.


Asunto(s)
Simulación de Dinámica Molecular , Proteínas , Proteínas/metabolismo , Difracción de Rayos X , Conformación Proteica
2.
J Patient Exp ; 11: 23743735241241179, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38515761

RESUMEN

The use of telehealth, specifically virtual visits, has increased and adoption continues. Providers need effective training for how to communicate with patients to develop a connection during virtual visits. This article describes the implementation and evaluation of a course called Mastering Presence in Virtual Visits. Results show that although providers perceive lack of time, technology issues, and lacking experiential knowledge as barriers to enacting course behaviors, the course was feasible and acceptable. Following the course, providers rated key course behaviors as helpful for practice, and 80.7% of providers were likely to recommend the course to a colleague. The course shifted provider perceptions of the purpose, patient experience, and procedures in virtual visits. Prior to the course, providers perceived virtual visits as fundamentally different than in-person visits. However, after the course, they recognized the importance of connection in virtual visits and how to foster that connection. Providers continue to require support in conducting high-quality virtual visits. Online, asynchronous courses, developed in partnership with providers, are feasible and effective for encouraging behavior change. Key findings: When asked on a needs assessment in 2020, communication strategies to connect with patients in virtual visits were a top provider need. Partnering with providers to create online, communication training content is effective for increasing the acceptability of courses about virtual visits. Asynchronous, online courses can meet provider needs for communication strategies to connect with patients in virtual visits.

3.
Obesity (Silver Spring) ; 32(5): 840-856, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38413012

RESUMEN

OBJECTIVE: This network meta-analysis evaluates the efficacy and safety of tirzepatide compared to glucagon-like peptide-1 receptor agonists (GLP-1 RA) and other weight loss drugs in the treatment of overweight and obesity. METHODS: MEDLINE, Embase, and Cochrane CENTRAL were searched for randomized controlled trials on tirzepatide, GLP-1 RA, and weight loss drugs approved by the US Food and Drug Administration. A network meta-analysis was performed, drawing direct and indirect comparisons between treatment groups. Network diagrams and surface under the cumulative ranking curve analysis were performed for primary (≥5%, ≥10%, ≥15%, absolute weight loss) and secondary outcomes and adverse effects. RESULTS: Thirty-one randomized controlled trials, involving more than 35,000 patients, were included in this study. Tirzepatide 15 mg ranked in the top three across weight-related parameters, glycemic profile (glycated hemoglobin), lipid parameters (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides), and blood pressure. Tirzepatide 15 mg had the highest efficacy compared with placebo for achieving ≥15% weight loss (risk ratio 10.24, 95% CI: 6.42-16.34). As compared to placebo, tirzepatide and GLP-1 RA across all doses had significant increases in gastrointestinal adverse effects. CONCLUSIONS: The superiority of tirzepatide and GLP-1 RA in inducing weight loss and their ability to target multiple metabolic parameters render them promising candidates in the treatment of patients with overweight and obesity.

4.
Curr Cardiol Rep ; 26(4): 199-210, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38376745

RESUMEN

PURPOSE OF REVIEW: The objective of this manuscript is to examine the current literature on the epidemiology of metabolic dysfunction-associated steatotic liver disease (MASLD), its correlation with cardiovascular disease (CVD) outcomes, as well as to evaluate the update in nomenclature from non-alcoholic liver disease (NAFLD). RECENT FINDINGS: The update of diagnostic criteria from NAFLD to MASLD reduces the stigma associated with alcohol consumption and poor health choices. It also shines a light on the crucial role of cardiometabolic risk factors in disease pathophysiology. The incidence and prevalence of MASLD are projected to increase significantly in the future as the population burden of cardiometabolic risk factors rises. MASLD is also a potent risk factor for developing CVD that should be tackled by using a multi-disciplinary team with a holistic approach. As the new nomenclature for metabolic liver disease is adopted on a global scale, more research is needed to investigate the applicability of findings from previous trials focusing on NAFLD. It is anticipated that the epidemic of MASLD will continue to increase globally, hence the urgent need for therapeutic approaches to reverse this trend.


Asunto(s)
Enfermedades Cardiovasculares , Enfermedad del Hígado Graso no Alcohólico , Humanos , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Factores de Riesgo , Consumo de Bebidas Alcohólicas , Enfermedades Cardiovasculares/epidemiología
5.
J Educ Teach Emerg Med ; 9(1): V15-V18, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38344055

RESUMEN

Intussusception is the telescoping of bowel into an adjacent segment of bowel and has an associated risk for bowel ischemia and perforation. The classic triad of abdominal pain, blood in stool, and an abdominal mass is present in less than 40% of pediatric cases and is less common in older children.1 Ultrasound has a high sensitivity and specificity for the diagnosis of intussusception, and once diagnosed, treatment modalities include reduction by either ultrasound or fluoroscopic guided air or hydrostatic enema. The risk of recurrence after successful reduction occurs in up to 12% of pediatric patients and occurs more frequently in older children and children with a pathologic lead point.2 We present a case of a 6-year-old child with colocolic intussusception that was successfully reduced and recurred within five days due to a large colonic polyp. Topics: Intussusception, lead point, pediatrics.

6.
bioRxiv ; 2024 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-37461732

RESUMEN

Proteins are molecular machines and to understand how they work, we need to understand how they move. New pump-probe time-resolved X-ray diffraction methods open up ways to initiate and observe protein motions with atomistic detail in crystals on biologically relevant timescales. However, practical limitations of these experiments demands parallel development of effective molecular dynamics approaches to accelerate progress and extract meaning. Here, we establish robust and accurate methods for simulating dynamics in protein crystals, a nontrivial process requiring careful attention to equilibration, environmental composition, and choice of force fields. With more than seven milliseconds of sampling of a single chain, we identify critical factors controlling agreement between simulation and experiments and show that simulated motions recapitulate ligand-induced conformational changes. This work enables a virtuous cycle between simulation and experiments for visualizing and understanding the basic functional motions of proteins.

7.
Cell Genom ; 3(10): 100409, 2023 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-37868034

RESUMEN

Genomic and transcriptomic analysis has furthered our understanding of many tumors. Yet, thyroid cancer management is largely guided by staging and histology, with few molecular prognostic and treatment biomarkers. Here, we utilize a large cohort of 251 patients with 312 samples from two tertiary medical centers and perform DNA/RNA sequencing, spatial transcriptomics, and multiplex immunofluorescence to identify biomarkers of aggressive thyroid malignancy. We identify high-risk mutations and discover a unique molecular signature of aggressive disease, the Molecular Aggression and Prediction (MAP) score, which provides improved prognostication over high-risk mutations alone. The MAP score is enriched for genes involved in epithelial de-differentiation, cellular division, and the tumor microenvironment. The MAP score also identifies aggressive tumors with lymphocyte-rich stroma that may benefit from immunotherapy. Future clinical profiling of the stromal microenvironment of thyroid cancer could improve prognostication, inform immunotherapy, and support development of novel therapeutics for thyroid cancer and other stroma-rich tumors.

8.
Cureus ; 15(9): e45829, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37881396

RESUMEN

Introduction The treatments and prognosis of bacterial meningitis differ greatly from those of aseptic meningitis, making early identification and differentiation essential. Several different clinical prediction rules have been developed to distinguish bacterial meningitis from aseptic meningitis. We sought to validate one clinical prediction rule for pediatric patients utilizing a centralized data warehouse that collects daily data from 184 hospitals across the United States. Methods We retrospectively collected data on all patients aged 29 days to 14 years who presented to Hospital Corporation of America (HCA) Healthcare hospitals from January 1, 2016, to May 31, 2021, with a diagnosis of meningitis. Our study replicated the original study of the meningitis score for emergencies (MSE) for the pediatric clinical prediction rule and assigned 3 points for procalcitonin (PCT) >1.2 ng/dL, 2 points for CSF protein >80 mg/dL, and 1 point for each of the other variables of C-reactive protein (CRP) >40 mg/L and CSF absolute neutrophil count >1000 cells per mm3. Patients were categorized either as having bacterial or aseptic meningitis. Using the clinical prediction rule, a calculation of the sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic (ROC) curve was performed. Results The optimum test characteristic was found to have a score of ≥ 3, showing a sensitivity of 92.86% (95% CI, 83.3-100), a specificity of 65.22% (95% CI, 51.5-79), a positive predictive value of 61.90% (95% CI, 47.2-76.6), and a negative predictive value of 93.75% (95% CI, 85.4-100). The ROC curve from this study showed an area under the curve (AUC) of 0.7892 (95% CI, 0.681-0.897). Conclusion Our study validated a high sensitivity for distinguishing bacterial meningitis from aseptic meningitis, suggesting the clinical prediction rule has clinical utility as a predictive screening tool. Although the original MSE advised a cutoff score of ≥1, our study suggests that a score ≥3 would give the best test performance.

9.
Nat Commun ; 14(1): 6174, 2023 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-37798281

RESUMEN

The control of Wnt receptor abundance is critical for animal development and to prevent tumorigenesis, but the mechanisms that mediate receptor stabilization remain uncertain. We demonstrate that stabilization of the essential Wingless/Wnt receptor Arrow/LRP6 by the evolutionarily conserved Usp46-Uaf1-Wdr20 deubiquitylase complex controls signaling strength in Drosophila. By reducing Arrow ubiquitylation and turnover, the Usp46 complex increases cell surface levels of Arrow and enhances the sensitivity of target cells to stimulation by the Wingless morphogen, thereby increasing the amplitude and spatial range of signaling responses. Usp46 inactivation in Wingless-responding cells destabilizes Arrow, reduces cytoplasmic accumulation of the transcriptional coactivator Armadillo/ß-catenin, and attenuates or abolishes Wingless target gene activation, which prevents the concentration-dependent regulation of signaling strength. Consequently, Wingless-dependent developmental patterning and tissue homeostasis are disrupted. These results reveal an evolutionarily conserved mechanism that mediates Wnt/Wingless receptor stabilization and underlies the precise activation of signaling throughout the spatial range of the morphogen gradient.


Asunto(s)
Proteínas de Drosophila , Vía de Señalización Wnt , Animales , Proteínas de Drosophila/metabolismo , Proteína Wnt1/genética , Proteína Wnt1/metabolismo , Drosophila/genética , Factores de Transcripción/metabolismo
10.
Nat Commun ; 14(1): 6173, 2023 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-37798301

RESUMEN

The relative abundance of Wnt receptors plays a crucial role in controlling Wnt signaling in tissue homeostasis and human disease. While the ubiquitin ligases that ubiquitylate Wnt receptors are well-characterized, the deubiquitylase that reverses these reactions remains unclear. Herein, we identify USP46, UAF1, and WDR20 (USP46 complex) as positive regulators of Wnt signaling in cultured human cells. We find that the USP46 complex is similarly required for Wnt signaling in Xenopus and zebrafish embryos. We demonstrate that Wnt signaling promotes the association between the USP46 complex and cell surface Wnt coreceptor, LRP6. Knockdown of USP46 decreases steady-state levels of LRP6 and increases the level of ubiquitylated LRP6. In contrast, overexpression of the USP46 complex blocks ubiquitylation of LRP6 by the ubiquitin ligases RNF43 and ZNFR3. Size exclusion chromatography studies suggest that the size of the USP46 cytoplasmic complex increases upon Wnt stimulation. Finally, we show that USP46 is essential for Wnt-dependent intestinal organoid viability, likely via its role in LRP6 receptor homeostasis. We propose a model in which the USP46 complex increases the steady-state level of cell surface LRP6 and facilitates the assembly of LRP6 into signalosomes via a pruning mechanism that removes sterically hindering ubiquitin chains.


Asunto(s)
Endopeptidasas , Vía de Señalización Wnt , beta Catenina , Animales , Humanos , beta Catenina/genética , beta Catenina/metabolismo , Ligasas/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baja Densidad/metabolismo , Receptores Wnt , Ubiquitina , Pez Cebra/metabolismo , Endopeptidasas/metabolismo
11.
Int J Mol Sci ; 24(13)2023 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-37446210

RESUMEN

Chromatin structure plays a fundamental role in regulating gene expression, with histone modifiers shaping the structure of chromatin by adding or removing chemical changes to histone proteins. The p53 transcription factor controls gene expression, binds target genes, and regulates their activity. While p53 has been extensively studied in cancer research, specifically in relation to fundamental cellular processes, including gene transcription, apoptosis, and cell cycle progression, its association with histone modifiers has received limited attention. This review explores the interplay between histone modifiers and p53 in regulating gene expression. We discuss how histone modifications can influence how p53 binds to target genes and how this interplay can be disrupted in cancer cells. This review provides insights into the complex mechanisms underlying gene regulation and their implications for potential cancer therapy.


Asunto(s)
Histonas , Proteína p53 Supresora de Tumor , Histonas/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Cromatina , Regulación de la Expresión Génica , Expresión Génica
12.
J Clin Invest ; 133(13)2023 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-37166989

RESUMEN

Although selenium deficiency correlates with colorectal cancer (CRC) risk, the roles of the selenium-rich antioxidant selenoprotein P (SELENOP) in CRC remain unclear. In this study, we defined SELENOP's contributions to sporadic CRC. In human single-cell cRNA-Seq (scRNA-Seq) data sets, we discovered that SELENOP expression rose as normal colon stem cells transformed into adenomas that progressed into carcinomas. We next examined the effects of Selenop KO in a mouse adenoma model that involved conditional, intestinal epithelium-specific deletion of the tumor suppressor adenomatous polyposis coli (Apc) and found that Selenop KO decreased colon tumor incidence and size. We mechanistically interrogated SELENOP-driven phenotypes in tumor organoids as well as in CRC and noncancer cell lines. Selenop-KO tumor organoids demonstrated defects in organoid formation and decreases in WNT target gene expression, which could be reversed by SELENOP restoration. Moreover, SELENOP increased canonical WNT signaling activity in noncancer and CRC cell lines. In defining the mechanism of action of SELENOP, we mapped protein-protein interactions between SELENOP and the WNT coreceptors low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6). Last, we confirmed that SELENOP-LRP5/6 interactions contributed to the effects of SELENOP on WNT activity. Overall, our results position SELENOP as a modulator of the WNT signaling pathway in sporadic CRC.


Asunto(s)
Adenoma , Neoplasias Colorrectales , Selenio , Ratones , Animales , Humanos , Vía de Señalización Wnt , Selenoproteína P/genética , Selenoproteína P/metabolismo , Neoplasias Colorrectales/patología , Selenio/metabolismo , Carcinogénesis/genética , Adenoma/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteína-5 Relacionada con Receptor de Lipoproteína de Baja Densidad/genética , Proteína-5 Relacionada con Receptor de Lipoproteína de Baja Densidad/metabolismo
13.
Int J Obes (Lond) ; 47(8): 677-685, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37253796

RESUMEN

BACKGROUND: Recent studies suggest that tirzepatide, a dual glucose-dependent insulinotropic-peptide (GIP) and glucagon-like peptide-1 receptor agonist (GLP-1 RA), has significant weight loss effects. This systematic review and meta-analysis aims to assess the efficacy and safety of tirzepatide for weight loss in patients with overweight or obesity. METHODS: Medline, Embase and Cochrane CENTRAL were searched for randomized controlled trials (RCTs) on tirzepatide's weight loss efficacy for these patients. A single arm meta-analysis of proportions estimated primary outcomes, ≥5%, ≥10%, and ≥15% weight loss, and adverse events (AEs); while meta-analysis of means estimated secondary outcomes. Comparative meta-analysis was conducted between tirzepatide and control arms where mean differences and odds ratios were estimated for continuous and dichotomous outcomes respectively. RESULTS: RCTs included in this study revealed that among 5800 patients, 78.22% (95% CI: 72.15% to 83.73%), 55.60% (95% CI: 46.54% to 64.47%), 32.28% (95% CI: 23.17% to 42.12%) achieved ≥5%, ≥10%, and ≥15% weight loss, respectively. Tirzepatide 5 mg demonstrated weight loss superiority relative to placebo (MD: -12.47 kg, 95% CI: -13.94 kg to -11.00 kg) and semaglutide (n = 1409, MD: -1.90 kg, 95% CI: -2.97 kg to -0.83 kg) with dose-dependent increase for 10 mg and 15 mg doses. The comparison between tirzepatide and semaglutide was examined in the SURPASS-2 trial that was included in this systematic review. For AEs, there was increase odds of experiencing gastrointestinal AEs with tirzepatide compared to placebo, but no significant difference with semaglutide. CONCLUSION: Tirzepatide has significant potential as a weight loss drug in patients with overweight and obesity, with little increase in AEs compared to other weight loss drugs. With its ability to concurrently target multiple aspects of metabolic syndrome, it should be considered as the next helm of weight loss therapies.


Asunto(s)
Fármacos Antiobesidad , Diabetes Mellitus Tipo 2 , Humanos , Sobrepeso/tratamiento farmacológico , Obesidad/tratamiento farmacológico , Polipéptido Inhibidor Gástrico , Fármacos Antiobesidad/efectos adversos , Pérdida de Peso , Hipoglucemiantes , Receptor del Péptido 1 Similar al Glucagón
14.
EClinicalMedicine ; 57: 101850, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36864983

RESUMEN

Background: Malnutrition and obesity are interdependent pathologies along the same spectrum. We examined global trends and projections of disability-adjusted life years (DALYs) and deaths from malnutrition and obesity until 2030. Methods: Using data from the 2019 Global Burden of Disease study involving 204 countries and territories, trends in DALYs and deaths were described for obesity and malnutrition from 2000 to 2019, stratified by geographical regions (as defined by WHO) and Socio-Demographic Index (SDI). Malnutrition was defined according to the 10th revision of International Classification of Diseases codes for nutritional deficiencies, stratified by malnutrition type. Obesity was measured via body mass index (BMI) using metrics related to national and subnational estimates, defined as BMI ≥25 kg/m2. Countries were stratified into low, low-middle, middle, high-middle, and high SDI bands. Regression models were constructed to predict DALYs and mortality up to 2030. Association between age-standardised prevalence of the diseases and mortality was also assessed. Findings: In 2019, age-standardised malnutrition-related DALYs was 680 (95% UI: 507-895) per 100,000 population. DALY rates decreased from 2000 to 2019 (-2.86% annually), projected to fall 8.4% from 2020 to 2030. Africa and low SDI countries observed highest malnutrition-related DALYs. Age-standardised obesity-related DALY estimates were 1933 (95% UI: 1277-2640). Obesity-related DALYs rose 0.48% annually from 2000 to 2019, predicted to increase by 39.8% from 2020 to 2030. Highest obesity-related DALYs were in Eastern Mediterranean and middle SDI countries. Interpretation: The ever-increasing obesity burden, on the backdrop of curbing the malnutrition burden, is predicted to rise further. Funding: None.

15.
Obesity (Silver Spring) ; 31(3): 832-840, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36748957

RESUMEN

OBJECTIVE: With rising prevalence of hypertension and obesity, the effect of hypertension in obesity remains an important global issue. The prognosis of the US general population with obesity based on hypertension control was examined. METHODS: This study examined participants from the National Health and Nutrition Examination Survey between 1999 and 2018. Individuals with obesity were stratified into no hypertension, controlled hypertension, and uncontrolled hypertension. The study outcome was all-cause mortality. Cox regression of all-cause mortality was adjusted for age, sex, ethnicity, diabetes, and previous myocardial infarction. RESULTS: Of 16,386 individuals with obesity, 53.1% had no hypertension, 24.7% had controlled hypertension, and 22.2% had uncontrolled hypertension. All-cause mortality was significantly higher in uncontrolled hypertension (17.1%), followed by controlled hypertension (14.8%) and no hypertension (4.0%). Uncontrolled hypertension had the highest mortality risk (hazard ratio [HR] 1.34, 95% CI: 1.13-1.59, p = 0.001), followed by controlled hypertension (HR 1.21, 95% CI: 1.10-1.34, p < 0.001), compared with no hypertension after adjustment. The excess mortality trend was more pronounced in females, those with diabetes, and those older than age 65 years. CONCLUSIONS: The incremental mortality risk in controlled and uncontrolled hypertension, compared with the normotensive counterparts, irrespective of sex, age, and diabetes status, urges health care providers to optimize hypertension control and advocate weight loss to achieve better outcomes in obesity.


Asunto(s)
Diabetes Mellitus , Hipertensión , Femenino , Humanos , Estados Unidos , Anciano , Encuestas Nutricionales , Hipertensión/epidemiología , Obesidad/epidemiología , Presión Sanguínea , Factores de Riesgo
16.
Sci Signal ; 16(771): eabn8372, 2023 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-36749823

RESUMEN

The Wnt-ß-catenin signal transduction pathway is essential for embryonic development and adult tissue homeostasis. Wnt signaling converts TCF from a transcriptional repressor to an activator in a process facilitated by the E3 ligase XIAP. XIAP-mediated monoubiquitylation of the transcriptional corepressor Groucho (also known as TLE) decreases its affinity for TCF, thereby allowing the transcriptional coactivator ß-catenin to displace it on TCF. Through a genome-scale screen in cultured Drosophila melanogaster cells, we identified the deubiquitylase USP47 as a positive regulator of Wnt signaling. We found that USP47 was required for Wnt signaling during Drosophila and Xenopus laevis development, as well as in human cells, indicating evolutionary conservation. In human cells, knockdown of USP47 inhibited Wnt reporter activity, and USP47 acted downstream of the ß-catenin destruction complex. USP47 interacted with TLE3 and XIAP but did not alter their amounts; however, knockdown of USP47 enhanced XIAP-mediated ubiquitylation of TLE3. USP47 inhibited ubiquitylation of TLE3 by XIAP in vitro in a dose-dependent manner, suggesting that USP47 is the deubiquitylase that counteracts the E3 ligase activity of XIAP on TLE. Our data suggest a mechanism by which regulated ubiquitylation and deubiquitylation of TLE enhance the ability of ß-catenin to cycle on and off TCF, thereby helping to ensure that the expression of Wnt target genes continues only as long as the upstream signal is present.


Asunto(s)
Vía de Señalización Wnt , beta Catenina , Animales , Humanos , beta Catenina/metabolismo , Drosophila , Drosophila melanogaster/metabolismo , Factores de Transcripción/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Xenopus
17.
Proc Natl Acad Sci U S A ; 120(2): e2208787120, 2023 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-36598937

RESUMEN

Wnt ligands are considered classical morphogens, for which the strength of the cellular response is proportional to the concentration of the ligand. Herein, we show an emergent property of bistability arising from feedback among the Wnt destruction complex proteins that target the key transcriptional co-activator ß-catenin for degradation. Using biochemical reconstitution, we identified positive feedback between the scaffold protein Axin and the kinase glycogen synthase kinase 3 (GSK3). Theoretical modeling of this feedback between Axin and GSK3 suggested that the activity of the destruction complex exhibits bistable behavior. We experimentally confirmed these predictions by demonstrating that cellular cytoplasmic ß-catenin concentrations exhibit an "all-or-none" response with sustained memory (hysteresis) of the signaling input. This bistable behavior was transformed into a graded response and memory was lost through inhibition of GSK3. These findings provide a mechanism for establishing decisive, switch-like cellular response and memory upon Wnt pathway stimulation.


Asunto(s)
Complejo de Señalización de la Axina , beta Catenina , Complejo de Señalización de la Axina/metabolismo , beta Catenina/metabolismo , Proteína Axina/genética , Proteína Axina/metabolismo , Glucógeno Sintasa Quinasa 3/metabolismo , Retroalimentación , Fosforilación , Vía de Señalización Wnt/fisiología
18.
Cancer Res ; 83(1): 3-11, 2023 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-36214645

RESUMEN

Tumor-associated macrophages (TAM) play an important role in supporting tumor growth and suppressing antitumor immune responses, and TAM infiltration has been associated with poor patient prognosis in various cancers. TAMs can be classified as pro-inflammatory, M1-like, or anti-inflammatory, M2-like. While multiple factors within the tumor microenvironment affect the recruitment, polarization, and functions of TAMs, accumulating evidence suggests that Wnt signaling represents an important, targetable driver of an immunosuppressive, M2-like TAM phenotype. TAM production of Wnt ligands mediates TAM-tumor cross-talk to support cancer cell proliferation, invasion, and metastasis. Targeting TAM polarization and the protumorigenic functions of TAMs through inhibitors of Wnt signaling may prove a beneficial treatment strategy in cancers where macrophages are prevalent in the microenvironment.


Asunto(s)
Macrófagos Asociados a Tumores , Vía de Señalización Wnt , Macrófagos , Proliferación Celular , Fenotipo , Microambiente Tumoral
19.
J Biol Chem ; 298(8): 102227, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35780831

RESUMEN

The Cullin-RING ligase 4 E3 ubiquitin ligase component Cereblon (CRBN) is a well-established target for a class of small molecules termed immunomodulatory drugs (IMiDs). These drugs drive CRBN to modulate the degradation of a number of neosubstrates required for the growth of multiple cancers. Whereas the mechanism underlying the activation of CRBN by IMiDs is well described, the normal physiological regulation of CRBN is poorly understood. We recently showed that CRBN is activated following exposure to Wnt ligands and subsequently mediates the degradation of a subset of physiological substrates. Among the Wnt-dependent substrates of CRBN is Casein kinase 1α (CK1α), a known negative regulator of Wnt signaling. Wnt-mediated degradation of CK1α occurs via its association with CRBN at a known IMiD binding pocket. Herein, we demonstrate that a small-molecule CK1α agonist, pyrvinium, directly prevents the Wnt-dependent interaction of CRBN with CK1α, attenuating the consequent CK1α degradation. We further show that pyrvinium disrupts the ability of CRBN to interact with CK1α at the IMiD binding pocket within the CRBN-CK1α complex. Of note, this function of pyrvinium is independent of its previously reported ability to enhance CK1α kinase activity. Furthermore, we also demonstrate that pyrvinium attenuates CRBN-induced Wnt pathway activation in vivo. Collectively, these results reveal a novel dual mechanism through which pyrvinium inhibits Wnt signaling by both attenuating the CRBN-mediated destabilization of CK1α and activating CK1α kinase activity.


Asunto(s)
Caseína Quinasa Ialfa , Compuestos de Pirvinio , Caseína Quinasa Ialfa/metabolismo , Compuestos de Pirvinio/farmacología , Ubiquitina-Proteína Ligasas/metabolismo , Vía de Señalización Wnt
20.
Cancers (Basel) ; 14(8)2022 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-35454763

RESUMEN

Anaplastic thyroid carcinoma (ATC) is the most aggressive endocrine neoplasm, with a median survival of just four to six months post-diagnosis. Even with surgical and chemotherapeutic interventions, the five-year survival rate is less than 5%. Although combination dabrafenib/trametinib therapy was recently approved for treatment of the ~25% of ATCs harboring BRAFV600E mutations, there are no approved, effective treatments for BRAF-wildtype disease. Herein, we perform a screen of 1525 drugs and evaluate therapeutic candidates using monolayer cell lines and four corresponding spheroid models of anaplastic thyroid carcinoma. We utilize three-dimensional culture methods, as they have been shown to more accurately recapitulate tumor responses in vivo. These three-dimensional cultures include four distinct ATC spheroid lines representing unique morphology and mutational drivers to provide drug prioritization that will be more readily translatable to the clinic. Using this screen, we identify three exceptionally potent compounds (bortezomib, cabazitaxel, and YM155) that have established safety profiles and could potentially be moved into clinical trial for the treatment of anaplastic thyroid carcinoma, a disease with few treatment options.

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