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1.
Cell ; 158(1): 171-84, 2014 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-24954536

RESUMO

Cancer cells that express oncogenic alleles of RAS typically require sustained expression of the mutant allele for survival, but the molecular basis of this oncogene dependency remains incompletely understood. To identify genes that can functionally substitute for oncogenic RAS, we systematically expressed 15,294 open reading frames in a human KRAS-dependent colon cancer cell line engineered to express an inducible KRAS-specific shRNA. We found 147 genes that promoted survival upon KRAS suppression. In particular, the transcriptional coactivator YAP1 rescued cell viability in KRAS-dependent cells upon suppression of KRAS and was required for KRAS-induced cell transformation. Acquired resistance to Kras suppression in a Kras-driven murine lung cancer model also involved increased YAP1 signaling. KRAS and YAP1 converge on the transcription factor FOS and activate a transcriptional program involved in regulating the epithelial-mesenchymal transition (EMT). Together, these findings implicate transcriptional regulation of EMT by YAP1 as a significant component of oncogenic RAS signaling.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sobrevivência Celular , Neoplasias do Colo/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Transição Epitelial-Mesenquimal , Neoplasias Pulmonares/tratamento farmacológico , Fosfoproteínas/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas ras/metabolismo , Animais , Proteínas de Ciclo Celular , Neoplasias do Colo/metabolismo , Sistemas de Liberação de Medicamentos , Células HCT116 , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais , Fatores de Transcrição , Ativação Transcricional , Proteínas de Sinalização YAP
2.
Nature ; 617(7959): 139-146, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37076617

RESUMO

Loss of the PTEN tumour suppressor is one of the most common oncogenic drivers across all cancer types1. PTEN is the major negative regulator of PI3K signalling. The PI3Kß isoform has been shown to play an important role in PTEN-deficient tumours, but the mechanisms underlying the importance of PI3Kß activity remain elusive. Here, using a syngeneic genetically engineered mouse model of invasive breast cancer driven by ablation of both Pten and Trp53 (which encodes p53), we show that genetic inactivation of PI3Kß led to a robust anti-tumour immune response that abrogated tumour growth in syngeneic immunocompetent mice, but not in immunodeficient mice. Mechanistically, PI3Kß inactivation in the PTEN-null setting led to reduced STAT3 signalling and increased the expression of immune stimulatory molecules, thereby promoting anti-tumour immune responses. Pharmacological PI3Kß inhibition also elicited anti-tumour immunity and synergized with immunotherapy to inhibit tumour growth. Mice with complete responses to the combined treatment displayed immune memory and rejected tumours upon re-challenge. Our findings demonstrate a molecular mechanism linking PTEN loss and STAT3 activation in cancer and suggest that PI3Kß controls immune escape in PTEN-null tumours, providing a rationale for combining PI3Kß inhibitors with immunotherapy for the treatment of PTEN-deficient breast cancer.


Assuntos
Evasão da Resposta Imune , Neoplasias Mamárias Animais , PTEN Fosfo-Hidrolase , Fosfatidilinositol 3-Quinase , Animais , Camundongos , Imunoterapia , Fosfatidilinositol 3-Quinase/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , PTEN Fosfo-Hidrolase/deficiência , PTEN Fosfo-Hidrolase/genética , Transdução de Sinais , Neoplasias Mamárias Animais/enzimologia , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/imunologia , Neoplasias Mamárias Experimentais/enzimologia , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/imunologia
3.
Blood ; 143(19): 1965-1979, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38271660

RESUMO

ABSTRACT: Acute myeloid leukemia (AML) is an aggressive hematological malignancy originating from transformed hematopoietic stem or progenitor cells. AML prognosis remains poor owing to resistance and relapse driven by leukemia stem cells (LSCs). Targeting molecules essential for LSC function is a promising therapeutic approach. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway is often dysregulated in AML. We found that although PI3Kγ is highly enriched in LSCs and critical for self-renewal, it was dispensable for normal hematopoietic stem cells. Mechanistically, PI3Kγ-AKT signaling promotes nuclear factor erythroid 2-related factor 2 (NRF2) nuclear accumulation, which induces 6-phosphogluconate dehydrogenase (PGD) and the pentose phosphate pathway, thereby maintaining LSC stemness. Importantly, genetic or pharmacological inhibition of PI3Kγ impaired expansion and stemness of murine and human AML cells in vitro and in vivo. Together, our findings reveal a key role for PI3Kγ in selectively maintaining LSC function by regulating AKT-NRF2-PGD metabolic pathway. Targeting the PI3Kγ pathway may, therefore, eliminate LSCs without damaging normal hematopoiesis, providing a promising therapeutic strategy for AML.


Assuntos
Classe Ib de Fosfatidilinositol 3-Quinase , Leucemia Mieloide Aguda , Células-Tronco Neoplásicas , Via de Pentose Fosfato , Animais , Humanos , Camundongos , Autorrenovação Celular , Classe Ib de Fosfatidilinositol 3-Quinase/metabolismo , Classe Ib de Fosfatidilinositol 3-Quinase/genética , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Via de Pentose Fosfato/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais
4.
J Cell Sci ; 135(3)2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35044463

RESUMO

PCTAIRE1 (also known as CDK16) is a serine-threonine kinase implicated in physiological processes like neuronal development, vesicle trafficking, spermatogenesis and cell proliferation. However, its exact role in cell division remains unclear. In this study, using a library screening approach, we identified PCTAIRE1 among several candidates that resisted mitotic arrest and mitotic cell death induced by polyomavirus small T (PolST) expression in mammalian cells. Our study showed that PCTAIRE1 is a mitotic kinase that localizes at centrosomes during G2 and at spindle poles as the cells enter mitosis, and then at the midbody during cytokinesis. We also report that PCTAIRE1 protein levels fluctuate through the cell cycle and reach their peak at mitosis, during which there is an increase in PCTAIRE1 phosphorylation as well. Interestingly, knockdown of PCTAIRE1 resulted in aberrant mitosis by interfering with spindle assembly and chromosome segregation. Further, we found that PCTAIRE1 promotes resistance of cancer cells to antimitotic drugs, and this underscores the significance of PCTAIRE1 as a potential drug target for overcoming chemotherapeutic resistance. Taken together, these studies establish PCTAIRE1 as a critical mediator of mitotic progression and highlight its role in chemotherapeutic resistance. This article has an associated First Person interview with the first author of the paper.


Assuntos
Antimitóticos , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Centrossomo/metabolismo , Segregação de Cromossomos , Células HeLa , Humanos , Masculino , Mitose , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Fuso Acromático/metabolismo
5.
Am J Pathol ; 193(6): 813-828, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36871751

RESUMO

The principal mechanism underlying the reduced rate of protein synthesis in atrophied skeletal muscle is largely unknown. Eukaryotic elongation factor 2 kinase (eEF2k) impairs the ability of eukaryotic translation elongation factor 2 (eEF2) to bind to the ribosome via T56 phosphorylation. Perturbations in the eEF2k/eEF2 pathway during various stages of disuse muscle atrophy have been investigated utilizing a rat hind limb suspension (HS) model. Two distinct components of eEF2k/eEF2 pathway misregulation were demonstrated, observing a significant (P < 0.01) increase in eEF2k mRNA expression as early as 1-day HS and in eEF2k protein level after 3-day HS. We set out to determine whether eEF2k activation is a Ca2+-dependent process with involvement of Cav1.1. The ratio of T56-phosphorylated/total eEF2 was robustly elevated after 3-day HS, which was completely reversed by 1,2-bis (2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM) and decreased by 1.7-fold (P < 0.05) by nifedipine. Transfection of C2C12 with cytomegalovirus promoter (pCMV)-eEF2k and administration with small molecules were used to modulate eEF2k and eEF2 activity. More importantly, pharmacologic enhancement of eEF2 phosphorylation induced phosphorylated ribosomal protein S6 kinase (T389) up-regulation and restoration of global protein synthesis in the HS rats. Taken together, the eEF2k/eEF2 pathway was up-regulated during disuse muscle atrophy involving calcium-dependent activation of eEF2k partly via Cav1.1. The study provides evidence, in vitro and in vivo, of the eEF2k/eEF2 pathway impact on ribosomal protein S6 kinase activity as well as protein expression of key atrophy biomarkers, muscle atrophy F-box/atrogin-1 and muscle RING finger-1.


Assuntos
Quinase do Fator 2 de Elongação , Músculo Esquelético , Ratos , Animais , Quinase do Fator 2 de Elongação/genética , Quinase do Fator 2 de Elongação/metabolismo , Fator 2 de Elongação de Peptídeos/genética , Fator 2 de Elongação de Peptídeos/metabolismo , Fosforilação , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo
6.
J Exp Biol ; 227(5)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38353270

RESUMO

The operating length of a muscle is a key determinant of its ability to produce force in vivo. Muscles that operate near the peak of their force-length relationship will generate higher forces whereas muscle operating at relatively short length may be safe from sudden lengthening perturbations and subsequent damage. At longer lengths, passive mechanical properties have the potential to contribute to force or constrain operating length with stiffer muscle-tendon units theoretically being restricted to shorter lengths. Connective tissues typically increase in density during aging, thus increasing passive muscle stiffness and potentially limiting the operating lengths of muscle during locomotion. Here, we compare in vivo and in situ muscle strain from the medial gastrocnemius in young (7 months old) and aged (30-32 months old) rats presumed to have varying passive tissue stiffness to test the hypothesis that stiffer muscles operate at shorter lengths relative to their force-length relationship. We measured in vivo muscle operating length during voluntary locomotion on inclines and flat trackways and characterized the muscle force-length relationship of the medial gastrocnemius using fluoromicrometry. Although no age-related results were evident, rats of both age groups demonstrated a clear relationship between passive stiffness and in vivo operating length, such that shorter operating lengths were significantly correlated with greater passive stiffness. Our results suggest that increased passive stiffness may restrict muscles to operating lengths shorter than optimal lengths, potentially limiting force capacity during locomotion.


Assuntos
Músculo Esquelético , Tendões , Ratos , Animais , Músculo Esquelético/fisiologia , Tendões/fisiologia , Tecido Conjuntivo , Locomoção , Membro Posterior , Contração Muscular/fisiologia , Fenômenos Biomecânicos
7.
J Exp Biol ; 227(8)2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38563306

RESUMO

Large and stout snakes commonly consume large prey and use rectilinear crawling; yet, whether body wall distention after feeding impairs rectilinear locomotion is poorly understood. After eating large prey (30-37% body mass), all Boa constrictor tested could perform rectilinear locomotion in the region with the food bolus despite a greatly increased distance between the ribs and the ventral skin that likely lengthens muscles relevant to propulsion. Unexpectedly, out of 11 kinematic variables, only two changed significantly (P<0.05) after feeding: cyclic changes in snake height increased by more than 1.5 times and the longitudinal movements of the ventral skin relative to the skeleton decreased by more than 25%. Additionally, cyclic changes in snake width suggest that the ribs are active and mobile during rectilinear locomotion, particularly in fed snakes, but also in unfed snakes. These kinematic changes suggest that rectilinear actuators reorient more vertically and undergo smaller longitudinal excursions following large prey ingestion, both of which likely act to reduce elongation of these muscles that may otherwise experience substantial strain.


Assuntos
Boidae , Locomoção , Comportamento Predatório , Animais , Fenômenos Biomecânicos , Locomoção/fisiologia , Boidae/fisiologia , Tamanho Corporal , Ingestão de Alimentos/fisiologia
8.
Hosp Pharm ; 59(3): 300-309, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38765000

RESUMO

Background: Infectious diseases (ID) pharmacists are pivotal members of antimicrobial stewardship teams. Prospective audit and feedback is a strong recommendation by The Infectious Diseases Society of America Guidelines for Antimicrobial Stewardship Programs (ASP). Utilizing customized ASP intervention documentation tools known as "ivents" in Epic, we aimed to assess the impact of interventions by measuring outcomes that were accepted compared to those that were rejected in a multihospital health system over 5 years. Methods: A multicenter, retrospective cohort study was conducted to compare clinical outcomes among intensive care unit (ICU) and non-ICU patients with accepted and rejected ASP interventions over 5 years from October 2015 to December 2020. Outcomes measured included antibiotic days of therapy per 1000 patient days (DOT/1000 PD), antibiotic doses per 1000 patient days (doses/1000 PD), hospital length of stay (LOS), in-hospital mortality, hospital-acquired Clostridioides difficile infection (HA-CDI), community-onset C. difficile infection (CO-CDI) within 30 days, and hospital readmission within 30 days. Coarsened exact matching (CEM) was used as a non-parametric matching method to balance covariates between groups and to control for confounding. Results: ASP recommendations by ID pharmacists were well-received by providers in a multihospital system over 5 years as evidenced by an overall acceptance rate of 92%. Acceptance of ASP interventions was associated with substantial reductions in antibiotic utilization without adversely affecting mortality or hospital readmissions. While high-risk C. difficile antibiotic use increased significantly due to frequent de-escalation to ceftriaxone among non-ICU patients with accepted interventions, rates of HA-CDI and CO-CDI within 30 days did not worsen. Furthermore, hospital LOS was notably shorter by an average of 1 day for non-ICU patients with accepted interventions, which resulted in substantial cost avoidance of $7 631 400. Conclusion: Collaboration with ID pharmacists to optimize antimicrobial stewardship was associated with significant reductions in antibiotic utilization, costs, and hospital LOS without worsening patient outcomes.

9.
J Exp Biol ; 226(21)2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37767690

RESUMO

Many animals use a combination of skeletal muscle and elastic structures to amplify power output for fast motions. Among vertebrates, tendons in series with skeletal muscle are often implicated as the primary power-amplifying spring, but muscles contain elastic structures at all levels of organization, from the muscle tendon to the extracellular matrix to elastic proteins within sarcomeres. The present study used ex vivo muscle preparations in combination with high-speed video to quantify power output, as the product of force and velocity, at several levels of muscle organization to determine where power amplification occurs. Dynamic ramp-shortening contractions in isolated frog flexor digitorum superficialis brevis were compared with isotonic power output to identify power amplification within muscle fibers, the muscle belly, free tendon and elements external to the muscle tendon. Energy accounting revealed that artifacts from compliant structures outside of the muscle-tendon unit contributed significant peak instantaneous power. This compliance included deflection of clamped bone that stored and released energy contributing 195.22±33.19 W kg-1 (mean±s.e.m.) to the peak power output. In addition, we found that power detected from within the muscle fascicles for dynamic shortening ramps was 338.78±16.03 W kg-1, or approximately 1.75 times the maximum isotonic power output of 195.23±8.82 W kg-1. Measurements of muscle belly and muscle-tendon unit also demonstrated significant power amplification. These data suggest that intramuscular tissues, as well as bone, have the capacity to store and release energy to amplify whole-muscle power output.


Assuntos
Músculo Esquelético , Tendões , Animais , Fenômenos Biomecânicos , Músculo Esquelético/fisiologia , Tendões/fisiologia , Contração Muscular/fisiologia , Sarcômeros
10.
Crit Rev Food Sci Nutr ; 63(9): 1170-1186, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34357823

RESUMO

Sorghum grain is a staple food for about 500 million people in 30 countries in Africa and Asia. Despite this contribution to global food production, most of the world's sorghum grain, and nearly all in Western countries, is used as animal feed. A combination of the increasingly important ability of sorghum crops to resist heat and drought, the limited history of the use of sorghum in Western foods, and the excellent functional properties of sorghum grain in healthy diets, suggests a greater focus on the development of new sorghum-based foods. An understanding of the structural and functional properties of sorghum grain to develop processes for production of new sorghum-based foods is required. In this review, we discuss the potential of sorghum in new food products, including sorghum grain composition, the functional properties of sorghum in foods, processing of sorghum-based products, the digestibility of sorghum protein and starch compared to other grains, and the health benefits of sorghum. In the potential for sorghum as a major ingredient in new foods, we suggest that the gluten-free status of sorghum is of relatively minor importance compared to the functionality of the slowly digested starch and the health benefits of the phenolic compounds present.


Assuntos
Sorghum , Animais , Sorghum/química , Grão Comestível/química , Amido/química , Ração Animal/análise , África
11.
Mol Biol Rep ; 51(1): 41, 2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38158512

RESUMO

While global climate change poses a significant environmental threat to agriculture, the increasing population is another big challenge to food security. To address this, developing crop varieties with increased productivity and tolerance to biotic and abiotic stresses is crucial. Breeders must identify traits to ensure higher and consistent yields under inconsistent environmental challenges, possess resilience against emerging biotic and abiotic stresses and satisfy customer demands for safer and more nutritious meals. With the advent of omics-based technologies, molecular tools are now integrated with breeding to understand the molecular genetics of genotype-based traits and develop better climate-smart crops. The rapid development of omics technologies offers an opportunity to generate novel datasets for crop species. Identifying genes and pathways responsible for significant agronomic traits has been made possible by integrating omics data with genetic and phenotypic information. This paper discusses the importance and use of omics-based strategies, including genomics, transcriptomics, proteomics and phenomics, for agricultural and horticultural crop improvement, which aligns with developing better adaptability in these crop species to the changing climate conditions.


Assuntos
Biotecnologia , Melhoramento Vegetal , Produtos Agrícolas/genética , Proteômica , Agricultura
12.
Nature ; 548(7668): 471-475, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28813415

RESUMO

Cyclin-dependent kinases 4 and 6 (CDK4/6) are fundamental drivers of the cell cycle and are required for the initiation and progression of various malignancies. Pharmacological inhibitors of CDK4/6 have shown significant activity against several solid tumours. Their primary mechanism of action is thought to be the inhibition of phosphorylation of the retinoblastoma tumour suppressor, inducing G1 cell cycle arrest in tumour cells. Here we use mouse models of breast carcinoma and other solid tumours to show that selective CDK4/6 inhibitors not only induce tumour cell cycle arrest, but also promote anti-tumour immunity. We confirm this phenomenon through transcriptomic analysis of serial biopsies from a clinical trial of CDK4/6 inhibitor treatment for breast cancer. The enhanced anti-tumour immune response has two underpinnings. First, CDK4/6 inhibitors activate tumour cell expression of endogenous retroviral elements, thus increasing intracellular levels of double-stranded RNA. This in turn stimulates production of type III interferons and hence enhances tumour antigen presentation. Second, CDK4/6 inhibitors markedly suppress the proliferation of regulatory T cells. Mechanistically, the effects of CDK4/6 inhibitors both on tumour cells and on regulatory T cells are associated with reduced activity of the E2F target, DNA methyltransferase 1. Ultimately, these events promote cytotoxic T-cell-mediated clearance of tumour cells, which is further enhanced by the addition of immune checkpoint blockade. Our findings indicate that CDK4/6 inhibitors increase tumour immunogenicity and provide a rationale for new combination regimens comprising CDK4/6 inhibitors and immunotherapies as anti-cancer treatment.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/imunologia , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Animais , Apresentação de Antígeno/efeitos dos fármacos , Apresentação de Antígeno/imunologia , Mimetismo Biológico/efeitos dos fármacos , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Humanos , Interferons/metabolismo , Camundongos , Fosforilação/efeitos dos fármacos , RNA de Cadeia Dupla/genética , Proteínas Repressoras/biossíntese , Transdução de Sinais/efeitos dos fármacos , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Transcriptoma , Vírus/efeitos dos fármacos , Vírus/genética , Vírus/imunologia
13.
Nature ; 546(7658): 426-430, 2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28607489

RESUMO

D-type cyclins (D1, D2 and D3) and their associated cyclin-dependent kinases (CDK4 and CDK6) are components of the core cell cycle machinery that drives cell proliferation. Inhibitors of CDK4 and CDK6 are currently being tested in clinical trials for patients with several cancer types, with promising results. Here, using human cancer cells and patient-derived xenografts in mice, we show that the cyclin D3-CDK6 kinase phosphorylates and inhibits the catalytic activity of two key enzymes in the glycolytic pathway, 6-phosphofructokinase and pyruvate kinase M2. This re-directs the glycolytic intermediates into the pentose phosphate (PPP) and serine pathways. Inhibition of cyclin D3-CDK6 in tumour cells reduces flow through the PPP and serine pathways, thereby depleting the antioxidants NADPH and glutathione. This, in turn, increases the levels of reactive oxygen species and causes apoptosis of tumour cells. The pro-survival function of cyclin D-associated kinase operates in tumours expressing high levels of cyclin D3-CDK6 complexes. We propose that measuring the levels of cyclin D3-CDK6 in human cancers might help to identify tumour subsets that undergo cell death and tumour regression upon inhibition of CDK4 and CDK6. Cyclin D3-CDK6, through its ability to link cell cycle and cell metabolism, represents a particularly powerful oncoprotein that affects cancer cells at several levels, and this property can be exploited for anti-cancer therapy.


Assuntos
Ciclina D3/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Aminopiridinas/farmacologia , Aminopiridinas/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Feminino , Glicólise/efeitos dos fármacos , Humanos , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Estresse Oxidativo/efeitos dos fármacos , Via de Pentose Fosfato/efeitos dos fármacos , Fosfofrutoquinase-1/metabolismo , Fosforilação/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/enzimologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Purinas/farmacologia , Purinas/uso terapêutico , Piruvato Quinase/metabolismo , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Serina/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Proc Natl Acad Sci U S A ; 117(3): 1772-1778, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31879350

RESUMO

Fluid fills intracellular, extracellular, and capillary spaces within muscle. During normal physiological activity, intramuscular fluid pressures develop as muscle exerts a portion of its developed force internally. These pressures, typically ranging between 10 and 250 mmHg, are rarely considered in mechanical models of muscle but have the potential to affect performance by influencing force and work produced during contraction. Here, we test a model of muscle structure in which intramuscular pressure directly influences contractile force. Using a pneumatic cuff, we pressurize muscle midcontraction at 260 mmHg and report the effect on isometric force. Pressurization reduced isometric force at short muscle lengths (e.g., -11.87% of P0 at 0.9 L0), increased force at long lengths (e.g., +3.08% of P0 at 1.25 L0), but had no effect at intermediate muscle lengths ∼1.1-1.15 L0 This variable response to pressurization was qualitatively mimicked by simple physical models of muscle morphology that displayed negative, positive, or neutral responses to pressurization depending on the orientation of reinforcing fibers representing extracellular matrix collagen. These findings show that pressurization can have immediate, significant effects on muscle contractile force and suggest that forces transmitted to the extracellular matrix via pressurized fluid may be important, but largely unacknowledged, determinants of muscle performance in vivo.


Assuntos
Fenômenos Biomecânicos , Líquidos Corporais/fisiologia , Pressão Hidrostática , Contração Muscular/fisiologia , Animais , Colágeno , Matriz Extracelular , Músculos Isquiossurais/fisiologia , Contração Isométrica , Modelos Biológicos , Músculo Esquelético/fisiologia , Rana catesbeiana
15.
Proc Natl Acad Sci U S A ; 117(39): 24427-24433, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32929011

RESUMO

PIK3CA hotspot mutation is well established as an oncogenic driver event in cancer and its durable and efficacious inhibition is a focus in the development and testing of clinical cancer therapeutics. However, hundreds of cancer-associated PIK3CA mutations remain uncharacterized, their sensitivity to PI3K inhibitors unknown. Here, we describe a series of PIK3CA C-terminal mutations, primarily nucleotide insertions, that produce a frame-shifted protein product with an extended C terminus. We report that these mutations occur at a low frequency across multiple cancer subtypes, including breast, and are sufficient to drive oncogenic transformation in vitro and in vivo. We demonstrate that the oncogenicity of these mutant p110α proteins is dependent on p85 but not Ras association. P110α-selective pharmacologic inhibition blocks transformation in cells and mammary tumors characterized by PIK3CA C-terminal mutation. Taken together, these results suggest patients with breast and other tumors characterized by PIK3CA C-terminal frameshift mutations may derive benefit from p110α-selective inhibitors, including the recently FDA-approved alpelisib.


Assuntos
Neoplasias da Mama/enzimologia , Classe I de Fosfatidilinositol 3-Quinases/química , Classe I de Fosfatidilinositol 3-Quinases/genética , Mutação da Fase de Leitura , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Classe Ia de Fosfatidilinositol 3-Quinase/genética , Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Feminino , Humanos , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Domínios Proteicos
16.
J Arthroplasty ; 38(9): 1839-1845.e1, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-36858130

RESUMO

BACKGROUND: Visceral obesity, a strong indicator of chronic inflammation and impaired metabolic health, has been shown to be associated with poor postoperative outcomes and complications. This study aimed to evaluate the relationship between visceral fat area (VFA) and periprosthetic joint infection (PJI) in total joint arthroplasty (TJA) patients. METHODS: A retrospective study of 484 patients who had undergone a total hip or knee arthroplasty was performed. All patients had a computed tomography scan of the abdomen/pelvis within two years of their TJA. Body composition data (ie, VFA, subcutaneous fat area, and skeletal muscle area) were calculated at the Lumbar-3 vertebral level via two fully automated and externally validated machine learning algorithms. A multivariable logistic model was created to determine the relationship between VFA and PJI, while accounting for other PJI risk factors. Of the 484 patients, 31 (6.4%) had a PJI complication. RESULTS: The rate of PJI among patients with VFA in the top quartile (> 264.1 cm2) versus bottom quartile (< 82.6 cm2) was 5.6% versus 10.6% and 18.8% versus 2.7% in the total hip arthroplasty and total knee arthroplasty cohorts, respectively. In the multivariate model, total knee arthroplasty patients with a VFA in the top quartile had a 30.5 times greater risk of PJI than those in the bottom quartile of VFA (P = .0154). CONCLUSION: VFA may have a strong association with PJI in TJA patients. Using a standardized imaging modality like computed tomography scans to calculate VFA can be a valuable tool for surgeons when assessing risk of PJI.


Assuntos
Artrite Infecciosa , Artroplastia de Quadril , Artroplastia do Joelho , Infecções Relacionadas à Prótese , Humanos , Artroplastia do Joelho/efeitos adversos , Estudos Retrospectivos , Infecções Relacionadas à Prótese/etiologia , Infecções Relacionadas à Prótese/complicações , Gordura Intra-Abdominal/diagnóstico por imagem , Artroplastia de Quadril/efeitos adversos , Fatores de Risco , Artrite Infecciosa/etiologia
17.
Int J Mol Sci ; 24(3)2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36769030

RESUMO

Serpins constitute a family of proteins with a very wide distribution in nature. Serpins have a well-conserved tertiary structure enabling irreversible protease inhibition or other specific biochemical functions. We examined the 189 putative wheat serpin genes previously identified by Benbow et al. (2019) via analysis of gene annotations (RefSeq v1.0) and combined our previous examinations of wheat ESTs and the 454 genome assembly. We found that 81 of the 189 putative serpin genes, plus two manually annotated genes, encode full-length, structurally conserved serpins. Expression of these serpin genes during wheat development and disease/abiotic stress responses was analysed using a publicly available RNAseq database. Results showed that the wheat LR serpins, homologous to Arabidopsis AtSerpin1 and barley BSZx, are ubiquitously expressed across all tissues throughout the wheat lifecycle, whereas the expression of other wheat serpin genes is tissue-specific, including expression only in the grain, only in the root, and only in the anther and microspore. Nine serpin genes were upregulated in both biotic and abiotic responses. Two genes in particular were highly expressed during disease and abiotic challenges. Our findings provide valuable information for further functional study of the wheat serpins, which in turn may lead to their application as molecular markers in wheat breeding.


Assuntos
Arabidopsis , Serpinas , Serpinas/genética , Serpinas/metabolismo , Triticum/genética , Triticum/metabolismo , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Estresse Fisiológico/genética , Desenvolvimento Vegetal , Filogenia , Regulação da Expressão Gênica de Plantas , Genoma de Planta
18.
Acta Neuropathol ; 143(6): 713-731, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35522298

RESUMO

Androgens and androgen-related molecules exert a plethora of functions across different tissues, mainly through binding to the transcription factor androgen receptor (AR). Despite widespread therapeutic use and misuse of androgens as potent anabolic agents, the molecular mechanisms of this effect on skeletal muscle are currently unknown. Muscle mass in adulthood is mainly regulated by the bone morphogenetic protein (BMP) axis of the transforming growth factor (TGF)-ß pathway via recruitment of mothers against decapentaplegic homolog 4 (SMAD4) protein. Here we show that, upon activation, AR forms a transcriptional complex with SMAD4 to orchestrate a muscle hypertrophy programme by modulating SMAD4 chromatin binding dynamics and enhancing its transactivation activity. We challenged this mechanism of action using spinal and bulbar muscular atrophy (SBMA) as a model of study. This adult-onset neuromuscular disease is caused by a polyglutamine expansion (polyQ) in AR and is characterized by progressive muscle weakness and atrophy secondary to a combination of lower motor neuron degeneration and primary muscle atrophy. Here we found that the presence of an elongated polyQ tract impairs AR cooperativity with SMAD4, leading to an inability to mount an effective anti-atrophy gene expression programme in skeletal muscle in response to denervation. Furthermore, adeno-associated virus, serotype 9 (AAV9)-mediated muscle-restricted delivery of BMP7 is able to rescue the muscle atrophy in SBMA mice, supporting the development of treatments able to fine-tune AR-SMAD4 transcriptional cooperativity as a promising target for SBMA and other conditions associated with muscle loss.


Assuntos
Atrofia Muscular Espinal , Receptores Androgênicos , Androgênios/metabolismo , Androgênios/farmacologia , Animais , Homeostase , Camundongos , Camundongos Transgênicos , Músculo Esquelético/patologia , Atrofia Muscular/metabolismo , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/metabolismo , Receptores Androgênicos/genética , Proteína Smad4
19.
J Cardiovasc Magn Reson ; 24(1): 71, 2022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-36517850

RESUMO

BACKGROUND: Image-domain motion correction of black-blood contrast T2-weighted fetal cardiovascular magnetic resonance imaging (CMR) using slice-to-volume registration (SVR) provides high-resolution three-dimensional (3D) images of the fetal heart providing excellent 3D visualisation of vascular anomalies [1]. However, 3D segmentation of these datasets, important for both clinical reporting and the application of advanced analysis techniques is currently a time-consuming process requiring manual input with potential for inter-user variability. METHODS: In this work, we present novel 3D fetal CMR population-averaged atlases of normal and abnormal fetal cardiovascular anatomy. The atlases are created using motion-corrected 3D reconstructed volumes of 86 third trimester fetuses (gestational age range 29-34 weeks) including: 28 healthy controls, 20 cases with postnatally confirmed neonatal coarctation of the aorta (CoA) and 38 vascular rings (21 right aortic arch (RAA), 17 double aortic arch (DAA)). We used only high image quality datasets with isolated anomalies and without any other deviations in the cardiovascular anatomy.In addition, we implemented and evaluated atlas-guided registration and deep learning (UNETR) methods for automated 3D multi-label segmentation of fetal cardiac vessels. We used images from CoA, RAA and DAA cohorts including: 42 cases for training (14 from each cohort), 3 for validation and 6 for testing. In addition, the potential limitations of the network were investigated on unseen datasets including 3 early gestational age (22 weeks) and 3 low SNR cases. RESULTS: We created four atlases representing the average anatomy of the normal fetal heart, postnatally confirmed neonatal CoA, RAA and DAA. Visual inspection was undertaken to verify expected anatomy per subgroup. The results of the multi-label cardiac vessel UNETR segmentation showed 100[Formula: see text] per-vessel detection rate for both normal and abnormal aortic arch anatomy. CONCLUSIONS: This work introduces the first set of 3D black-blood T2-weighted CMR atlases of normal and abnormal fetal cardiovascular anatomy including detailed segmentation of the major cardiovascular structures. Additionally, we demonstrated the general feasibility of using deep learning for multi-label vessel segmentation of 3D fetal CMR images.


Assuntos
Coartação Aórtica , Cardiopatias Congênitas , Humanos , Lactente , Recém-Nascido , Aorta Torácica/diagnóstico por imagem , Coração Fetal/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética , Valor Preditivo dos Testes
20.
J Pathol ; 253(3): 292-303, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33166087

RESUMO

Loss of the tumor suppressor gene Pten in murine prostate recapitulates human carcinogenesis and causes stromal proliferation surrounding murine prostate intraepithelial neoplasia (mPIN), which is reactive to microinvasion. In turn, invasion has been shown to be regulated in part by de novo fatty acid synthesis in prostate cancer. We therefore investigated the effects of genetic ablation of Fasn on invasive potential in prostate-specific Pten knockout mice. Combined genetic ablation of Fasn and Pten reduced the weight and volume of all the prostate lobes when compared to single knockouts. The stromal reaction to microinvasion and the cell proliferation that typically occurs in Pten knockout were largely abolished by Fasn knockout. To verify that Fasn knockout indeed results in decreased invasive potential, we show that genetic ablation and pharmacologic inhibition of FASN in prostate cancer cells significantly inhibit cellular motility and invasion. Finally, combined loss of PTEN with FASN overexpression was associated with lethality as assessed in 660 prostate cancer patients with 14.2 years of median follow-up. Taken together, these findings show that de novo lipogenesis contributes to the aggressive phenotype induced by Pten loss in murine prostate and targeting Fasn may reduce the invasive potential of prostate cancer driven by Pten loss. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.


Assuntos
Ácido Graxo Sintase Tipo I/genética , PTEN Fosfo-Hidrolase/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Movimento Celular/genética , Ácido Graxo Sintase Tipo I/metabolismo , Humanos , Lipogênese/fisiologia , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Neoplasias da Próstata/patologia
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