Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 142
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Exp Cell Res ; 411(1): 112731, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34270980

RESUMO

Adhesion of cells to each other and to the extracellular matrix (ECM) are both required for cellular functions. Cell-to-cell adhesion is mediated by cadherins, and their engagement triggers the activation of Stat3, which offers a potent survival signal. Adhesion to the ECM on the other hand, activates FAK which attracts and activates Src, as well as receptor tyrosine kinases (RTKs), the PI3k/Akt and Ras/Erk pathways. However, the effect of cell density upon FAK and Akt activity has not been examined. We now demonstrate that, interestingly, despite being potent Stat3 activators, Src and RTKs are unable to activate Stat3 in sparsely growing (i.e., without cadherin engagement), non-neoplastic cells attached to the ECM. In contrast, cell aggregation (i.e., cadherin engagement in the absence of adhesion to a solid substratum) was found to activate both Stat3 and Akt. Pharmacologic or genetic reduction of FAK activity abolished Akt activity at low densities, indicating that FAK is an important activator of Akt in this setting. Notably, FAK knockout increased cellular sensitivity to the Stat3 inhibitor CPA7, while FAK reintroduction restored resistance to this drug. These findings suggest a complementary role of integrin/FAK/Akt and cadherin/Stat3-mediated pro-survival pathways, which may be of significance during neoplastic transformation and metastasis.

2.
Exp Cell Res ; 404(1): 112601, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33957118

RESUMO

Adhesion of cells to each other and to the extracellular matrix (ECM) are both required for cellular functions. Cell-to-cell adhesion is mediated by cadherins and their engagement triggers the activation of Stat3, which offers a potent survival signal. Adhesion to the ECM on the other hand, activates FAK which attracts and activates Src, as well as receptor tyrosine kinases (RTKs), the PI3k/Akt and Ras/Erk pathways. However, the effect of cell density upon FAK and Akt activity has not been examined. We now demonstrate that, interestingly, despite being potent Stat3 activators, Src and RTKs are unable to activate Stat3 in sparsely growing (i.e., without cadherin engagement), non-neoplastic cells attached to the ECM. In contrast, cell aggregation (i.e., cadherin engagement in the absence of adhesion to a solid substratum) was found to activate both Stat3 and Akt. Pharmacologic or genetic reduction of FAK activity abolished Akt activity at low densities, indicating that FAK is an important activator of Akt in this setting. Notably, FAK knockout increased cellular sensitivity to the Stat3 inhibitor CPA7, while FAK reintroduction restored resistance to this drug. These findings suggest a complementary role of integrin/FAK/Akt and cadherin/Stat3-mediated pro-survival pathways, which may be of significance during neoplastic transformation and metastasis.


Assuntos
Caderinas/metabolismo , Fibroblastos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Adesão Celular/fisiologia , Sobrevivência Celular/fisiologia , Transformação Celular Neoplásica/metabolismo , Matriz Extracelular/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/fisiologia
3.
J Sports Sci Med ; 21(4): 586-594, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36523890

RESUMO

Drive volley is one of the essential backhand stroke technique trends seen in recent women's tennis competitions. Although movements of the drive volley and groundstroke are similar, activation of the internal muscles vary due to different incoming ball conditions. Most previous studies only focused on the groundstroke, however. The current study investigates the different muscle activation patterns in the upper extremity muscle during the two-handed backhand drive volley as well as the groundstroke for female tennis players. Ten elite female tennis players were measured in the muscle activation of the flexor carpi radialis (FCR), extensor carpi radialis (ECR), biceps brachii (BB), and triceps brachii (TB) from both upper extremities. Racket-head speed at impact, swing duration of each phase, and racket-head average velocity in both strokes were also recorded. Significant differences were found between the drive volley and groundstroke in the velocity profile of racket tip, swing duration of each phase (preparation, early follow-through, and late follow-through), activation patterns of upper extremity muscles, and flexor/ extensor ratios of wrist and elbow in both upper extremities. Different racket trajectory strategies were also observed between the two strokes, with greater horizontal racket velocity recorded in the groundstroke but greater vertical velocity in the drive volley. ECR and TB muscle activation during the drive volley preparation phase was greater than the groundstroke when completing a quicker backswing. In the early acceleration phase, the greater FCR leading arm activation in the drive volley assisted wrist stabilization in preparation for impact. In the late follow-through phase, less TB leading arm activity and higher ECR trailing arm activity in the drive volley showed more forward compression movement in racket contact with the ball. As it is essential for the drive volley to complete a quicker backswing and to increase shot efficiency at the end of the forward movement, coaches should consider the two strokes' muscle activation and technique differences to enhance specific techniques and fitness training programs.


Assuntos
Articulação do Cotovelo , Tênis , Feminino , Humanos , Tênis/fisiologia , Punho/fisiologia , Braço/fisiologia , Articulação do Cotovelo/fisiologia , Músculo Esquelético/fisiologia
4.
FASEB J ; 34(4): 5106-5127, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32068312

RESUMO

Excessive proliferation and apoptosis-resistance are hallmarks of cancer. Increased dynamin-related protein 1 (Drp1)-mediated mitochondrial fission is one of the mediators of this phenotype. Mitochondrial fission that accompanies the nuclear division is called mitotic fission and occurs when activated Drp1 binds partner proteins on the outer mitochondrial membrane. We examine the role of Drp1-binding partners, mitochondrial dynamics protein of 49 and 51 kDa (MiD49 and MiD51), as drivers of cell proliferation and apoptosis-resistance in non-small cell lung cancer (NSCLC) and invasive breast carcinoma (IBC). We also evaluate whether inhibiting MiDs can be therapeutically exploited to regress cancer. We show that MiD levels are pathologically elevated in NSCLC and IBC by an epigenetic mechanism (decreased microRNA-34a-3p expression). MiDs silencing causes cell cycle arrest through (a) increased expression of cell cycle inhibitors, p27Kip1 and p21Waf1 , (b) inhibition of Drp1, and (c) inhibition of the Akt-mTOR-p70S6K pathway. Silencing MiDs leads to mitochondrial fusion, cell cycle arrest, increased apoptosis, and tumor regression in a xenotransplant NSCLC model. There are positive correlations between MiD expression and tumor size and grade in breast cancer patients and inverse correlations with survival in NSCLC patients. The microRNA-34a-3p-MiDs axis is important to cancer pathogenesis and constitutes a new therapeutic target.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Ciclo Celular , Epigênese Genética , Neoplasias Pulmonares/patologia , Proteínas Mitocondriais/metabolismo , Fatores de Alongamento de Peptídeos/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/terapia , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/terapia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Dinâmica Mitocondrial , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Fatores de Alongamento de Peptídeos/antagonistas & inibidores , Fatores de Alongamento de Peptídeos/genética , Prognóstico , Taxa de Sobrevida , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
5.
J Sports Sci ; 38(3): 280-287, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31766951

RESUMO

Delivering a cricket ball with a wrist-spin (WS) bowling technique is considered one of the game's most difficult skills. Limited biomechanical information exists for WS bowlers across skill levels. The purpose of this study was to compare biomechanical, isokinetic strength and anthropometric measures between elite (12) and pathway bowlers (eight). Data were collected using a motion analysis system, dynamometer and a level-two anthropometrist. A regression analysis identified that performance was best explained by increased wrist radial deviation torque and longitudinal axis rotational moments at the shoulder and wrist. From back foot impact (BFI) to ball release (BR), elite bowlers rotated their trunks less, experienced less trunk deceleration resulting in a more front-on position and increased pelvis rotation angular velocity. They also displayed an increased shoulder internal rotation moment as the upper arm moved from external into internal rotation and was a major contributor in the subsequent differences observed in the distal segments of the bowling limb. Anthropometric differences were observed at the wrist and finger joints and may be used to form the basis for talent identification programmes. This study highlights the important contribution to bowling performance of the musculature responsible for producing long axis rotations of the bowling limb.


Assuntos
Antropometria , Desempenho Atlético/fisiologia , Críquete/fisiologia , Destreza Motora/fisiologia , Força Muscular/fisiologia , Extremidade Superior/fisiologia , Adolescente , Adulto , Humanos , Masculino , Pelve/fisiologia , Amplitude de Movimento Articular/fisiologia , Rotação , Tórax/fisiologia , Estudos de Tempo e Movimento , Adulto Jovem
6.
Breast Cancer Res ; 21(1): 12, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30678714

RESUMO

BACKGROUND: Limited understanding of the cancer biology of metastatic sites is a major factor contributing to poor outcomes in cancer patients. The regional lymph nodes are the most common site of metastasis in most solid cancers and their involvement is a strong predictor of relapse in breast cancer (BC). We have previously shown that ezrin, a cytoskeletal-membrane linker protein, is associated with lymphovascular invasion and promotes metastatic progression in BC. However, the efficacy of pharmacological inhibition of ezrin in blocking cancer cell migration and metastasis remains unexplored in BC. METHODS: We quantified ezrin expression in a BC tissue microarray (n = 347) to assess its correlation with risk of relapse. Next, we developed a quantitative intravital microscopy (qIVM) approach, using a syngeneic lymphatic reporter mouse tumor model, to investigate the effect of systemic ezrin inhibition on cancer cell migration and metastasis. RESULTS: We show that ezrin is expressed at significantly higher levels in lymph node metastases compared to matched primary tumors, and that a high tumor ezrin level is associated with increased risk of relapse in BC patients with regional disease. Using qIVM, we observe a subset of cancer cells that retain their invasive and migratory phenotype at the tumor-draining lymph node. We further show that systemic inhibition of ezrin, using a small molecule compound (NSC668394), impedes the migration of cancer cells in vivo. Furthermore, systemic ezrin inhibition leads to reductions in metastatic burden at the distal axillary lymph node and lungs. CONCLUSIONS: Our findings demonstrate that the tumor ezrin level act as an independent biomarker in predicting relapse and provide a rationale for therapeutic targeting of ezrin to reduce the metastatic capacity of cancer cells in high-risk BC patients with elevated ezrin expression.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Proteínas do Citoesqueleto/metabolismo , Neoplasias Pulmonares/patologia , Recidiva Local de Neoplasia/patologia , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/antagonistas & inibidores , Mama/patologia , Neoplasias da Mama/diagnóstico por imagem , Linhagem Celular Tumoral/transplante , Movimento Celular/efeitos dos fármacos , Estudos de Coortes , Proteínas do Citoesqueleto/antagonistas & inibidores , Modelos Animais de Doenças , Feminino , Genes Reporter , Humanos , Microscopia Intravital , Pulmão/diagnóstico por imagem , Pulmão/patologia , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/secundário , Linfonodos/diagnóstico por imagem , Linfonodos/efeitos dos fármacos , Linfonodos/patologia , Metástase Linfática/diagnóstico por imagem , Metástase Linfática/patologia , Metástase Linfática/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pessoa de Meia-Idade , Fenóis/farmacologia , Fenóis/uso terapêutico , Quinolonas/farmacologia , Quinolonas/uso terapêutico , Análise Serial de Tecidos
7.
FASEB J ; : fj201800120R, 2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29812973

RESUMO

Triple-negative breast cancers (TNBCs) account for ∼25% of all invasive carcinomas and represent a large subset of aggressive, high-grade tumors. Despite current research focused on understanding the genetic landscape of TNBCs, reliable prognostic and predictive biomarkers remain limited. Although dysregulated microRNAs (miRNAs) have emerged as key players in many cancer types, the role of miRNAs in TNBC disease progression is unclear. We performed miRNA profiling of 51 TNBCs by next-generation sequencing to reveal differentially expressed miRNAs. A total of 228 miRNAs were identified. Three miRNAs (miR-224-5p, miR-375, and miR-205-5p) separated the tumors based on basal status. Six miRNAs (high let-7d-3p, miR-203b-5p, and miR-324-5p; low miR-30a-3p, miR-30a-5p, and miR-199a-5p) were significantly associated with decreased overall survival (OS) and 5 miRNAs (high let-7d-3p; low miR-30a-3p, miR-30a-5p, miR-30c-5p, and miR-128-3p) with decreased relapse-free survival (RFS). On multivariate analysis, high expression of let-7d-3p and low expression of miR-30a were independent predictors of decreased OS and RFS. High expression of miR-95-3p was significantly associated with decreased OS and RFS in patients treated with anthracycline-based chemotherapy. Five miRNAs (let-7d-3p, miR-30a-3p, miR-30c-5p, miR-128-3p, and miR-95-3p) were validated by quantitative RT-PCR. Our findings unveil novel prognostic and predictive miRNA targets for TNBC, including a miRNA signature that predicts patient response to anthracycline-based chemotherapy. This may improve clinical management and/or lead to the development of novel therapies.-Turashvili, G., Lightbody, E. D., Tyryshkin, K., SenGupta, S. K., Elliott, B. E., Madarnas, Y., Ghaffari, A., Day, A., Nicol, C. J. B. Novel prognostic and predictive microRNA targets for triple-negative breast cancer.

8.
Clin Chem Lab Med ; 57(3): 375-382, 2019 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-30375343

RESUMO

This position paper presents the role of laboratory test results in traditional general practice and provides a recommendation for responsible sharing of results with patients for improved safety, efficiency and outcomes. This paper looks at the relationship between the laboratory, the general practitioner consultation, the patient, safety and general practice capacity. We suggest changes in the traditional practice of communicating laboratory test results whereby normal or abnormal results are made available to patients as soon as they become available. We also endorse the opinion that using online tools such as email or text messages could enhance the provision of rapid access to laboratory test results for patients.


Assuntos
Registros Eletrônicos de Saúde , Correio Eletrônico , Clínicos Gerais , Laboratórios , Relações Médico-Paciente , Medicina Geral , Humanos
9.
Int J Sports Med ; 40(3): 191-199, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30630192

RESUMO

This study aimed to develop a 2-dimensional (2D) video screening tool capable of predicting an athlete's peak 3-dimensional (3D) knee moments during unplanned sidestepping. 2D video-based kinematic measures were simultaneously captured with 3D peak knee moments for 30 female field hockey players (15 junior, 15 senior). Intra- and intertester repeatability of 2D kinematic measures was performed. Then, linear regression models were used to model 3D knee moments from 2D kinematic variables utilizing 80% of the sample (n=24). Regression equations were then validated on the remaining 20% of the sample (n=6). Angular 2D measures had good-excellent intra- (ICC=0.936-0.998) and intertester (ICC=0.662-0.949) reliability. Displacement measures had poor-excellent intra- (ICC=0.377-0.539) and inter-tester (ICC=0.219-0.869) reliability. Significant independent predictors of peak knee moments were dynamic knee valgus, knee flexion angle at foot strike, trunk flexion range of motion (ROM), trunk lateral flexion, hip abduction and knee flexion ROM (P<0.05). Regression equations generated from these models effectively predicted peak knee extension, valgus and internal rotation moments (i. e., were not different from measured values P>0.05, ES<0.4) in the 20% subsample. 2D video-based measurements of an athlete's full body kinematics during unplanned sidestepping provide a reliable, specific, sensitive and cost-effective means for screening female team sport athletes.


Assuntos
Lesões do Ligamento Cruzado Anterior/diagnóstico , Hóquei/lesões , Programas de Rastreamento/métodos , Gravação em Vídeo , Adolescente , Lesões do Ligamento Cruzado Anterior/fisiopatologia , Fenômenos Biomecânicos , Feminino , Pé/fisiopatologia , Quadril/fisiopatologia , Humanos , Articulação do Joelho/fisiopatologia , Modelos Lineares , Movimento , Amplitude de Movimento Articular , Tronco/fisiopatologia , Adulto Jovem
10.
J Sports Sci ; 37(5): 515-524, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30175947

RESUMO

Magnetic and inertial measurement units (MIMUs) may provide an accessible, three-dimensional, in-field alternative to laboratory-restricted marker-based motion capture. Existing upper limb MIMU models have predominantly been validated with low-velocity motion and their suitability for use with sport-based movements remains relatively untested. We propose a MIMU system approach to enable the estimation of anatomically meaningful and participant-specific elbow kinematics with considerations for use with cricket bowling. A novel standardised elbow reference posture of 90 degrees flexion and 0 deg pronation, and functional definition of elbow joint axes of rotation calibrated the MIMU method model before it was validated across three experiments: (1) simple elbow rotations with a mechanical linkage; (2) low-velocity elbow rotations in human participants; and (3) low-medium velocity sport-based movements in human participants. The proposed MIMU method demonstrated high elbow kinematic measurement agreement when compared with a criterion measure across all three conditions. However, during experiment 3, sensor components neared their measurement capacity and the MIMU method elbow flexion measurement variability increased. We conclude that the proposed MIMU method can estimate anatomically referenced, participant-specific joint angles, however, the hardware specifications of currently available systems may limit application in high-velocity/acceleration situations, preventing the measurement of cricket bowling in-field for now.


Assuntos
Articulação do Cotovelo/fisiologia , Fenômenos Magnéticos , Esportes/fisiologia , Estudos de Tempo e Movimento , Aceleração , Fenômenos Biomecânicos , Calibragem , Estudos de Viabilidade , Humanos , Movimento , Amplitude de Movimento Articular , Rotação
12.
Exp Cell Res ; 361(1): 112-125, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29031557

RESUMO

It was previously demonstrated that differentiation of some established breast epithelial cell lines requires confluence and stimulation with hydrocortisone, insulin and prolactin inducers. We and others previously demonstrated that E-cadherin engagement, which is favored under conditions of confluence, increases the levels and activity of the Rac small GTPase. To investigate the functional relationship between the transforming ability of Rac and its role as an integral component of the differentiative E-cadherin signaling pathway, we introduced a mutationally activated form of Rac, RacV12, into the mouse breast epithelium-derived cell line, HC11. Our results demonstrate that the strength of the Rac signal is key for the outcome of the differentiation process; cRac1 is critically required for differentiation, and at low levels, mutationally activated RacV12 is able to increase differentiation, presumably reinforcing the E-cadherin/Rac differentiative signal. However, high RacV12 expression blocked differentiation concomitant with E-cadherin downregulation, while inducing neoplastic transformation. Therefore, the intensity of the Rac signal is a central determinant in the balance between cell proliferation vs differentiation, two fundamentally opposed processes, a finding which could also have important therapeutic implications.


Assuntos
Caderinas/metabolismo , Diferenciação Celular , Células Epiteliais/citologia , Glândulas Mamárias Animais/citologia , Proteínas rac de Ligação ao GTP/metabolismo , Animais , Células Cultivadas , Células Epiteliais/metabolismo , Feminino , Glândulas Mamárias Animais/metabolismo , Camundongos , Transdução de Sinais
13.
Scand J Med Sci Sports ; 28(6): 1691-1699, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29415324

RESUMO

With advances in technology, scientists are now able to more accurately measure elbow displacement changes during the cricket bowling action. This has led to the realization that the majority of bowlers undergo some degree of elbow extension during the forward swing phase of bowling. Consequently, the International Cricket Council were obliged to revise the once zero tolerance for elbow extension threshold to a 15° range. However, it is still not understood if bowling with >15° of elbow extension aids performance or alters other kinematic movements. The purpose of this study was to compare performance and technique measures between legal and illegal finger-spin bowlers. Data were collected from 48 pathway and elite bowlers using a 22-camera motion analysis system. Results indicated that the ball velocity and revolutions at ball release of pathway bowlers with illegal actions showed no significant difference and were similar to elite legal bowlers. Technique differences were also identified, with illegal bowlers being more front-on, forcing a reliance on increased elbow flexion and supination to impart effective ball kinematics at ball release. The performance benefit of greater ball velocity and revolutions is obtained when finger-spin bowlers deliver the ball with more than the allowable 15° of elbow extension, thus reinforcing the validity of the current bowling laws. To counteract bowling with an illegal action, it is recommended that a more side-on technique at back foot impact and rotating the trunk through to the point of ball release will assist bowlers in reducing undesirable elbow extension levels.


Assuntos
Desempenho Atlético/normas , Fenômenos Biomecânicos , Cotovelo/fisiologia , Dedos/fisiologia , Esportes/normas , Adolescente , Adulto , , Humanos , Masculino , Rotação , Análise e Desempenho de Tarefas , Tronco , Gravação em Vídeo , Adulto Jovem
14.
J Sports Sci ; 36(6): 651-659, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28532284

RESUMO

Spin bowling plays a fundamental role within the game of cricket yet little is known about the initial ball kinematics in elite and pathway spin bowlers or their relationship to performance. Therefore, the purpose of this study was to record three-dimensional ball kinematics in a large and truly high level cohort of elite and pathway finger-spin (FS) and wrist-spin (WS) bowlers, identifying potential performance measures that can be subsequently used in future research. A 22-camera Vicon motion analysis system captured retro-reflective markers placed on the seam (static) and ball (dynamic) to quantify ball kinematics in 36 FS (12 elite and 24 pathway) and 20 WS (eight elite and 12 pathway) bowlers. Results indicated that FS bowlers delivered the ball with an increased axis of rotation elevation, while wrist-spin bowlers placed greater amounts of revolutions on the ball. It also highlighted that ball release (BR) velocity, revolutions and velocity/revolution index scores for both groups and seam stability for FS bowlers, and seam azimuth angle and spin axis elevation angle for WS bowlers, were discriminators of playing level. As such these variables could be used as indicators of performance (i.e. performance measures) in future research.


Assuntos
Desempenho Atlético/fisiologia , Dedos/fisiologia , Destreza Motora/fisiologia , Equipamentos Esportivos , Esportes/fisiologia , Punho/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Rotação , Estudos de Tempo e Movimento , Adulto Jovem
15.
Cytokine ; 82: 70-9, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26876578

RESUMO

Here we report that the STAT5A transcription factor is a direct p53 transcriptional target gene. STAT5A is well expressed in p53 wild type cells but not in p53-null cells. Inhibition of p53 reduces STAT5A expression. DNA damaging agents such as doxorubicin also induced STAT5A expression in a p53 dependent manner. Two p53 binding sites were mapped in the STAT5A gene and named PBS1 and PBS2; these sites were sufficient to confer p53 responsiveness in a luciferase reporter gene. Chromatin immunoprecipitation experiments revealed that PBS2 has constitutive p53 bound to it, while p53 binding to PBS1 required DNA damage. In normal human breast lobules, weak p53 staining correlated with regions of intense STAT5A staining. Interestingly, in a cohort of triple negative breast tumor tissues there was little correlation between regions of p53 and STAT5A staining, likely reflecting a high frequency of p53 mutations that stabilize the protein in these tumors. We thus reveal an unexpected connection between cytokine signaling and p53.


Assuntos
Neoplasias da Mama/metabolismo , Dano ao DNA , Mutação , Elementos de Resposta , Fator de Transcrição STAT5/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Feminino , Humanos , Células MCF-7 , Fator de Transcrição STAT5/genética , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/genética
16.
Inj Prev ; 22(2): 123-8, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26399611

RESUMO

BACKGROUND: Exercise-based training programmes are commonly used to prevent sports injuries but programme effectiveness within community men's team sport is largely unknown. OBJECTIVE: To present the intention-to-treat analysis of injury outcomes from a clustered randomised controlled trial in community Australian football. METHODS: Players from 18 male, non-elite, community Australian football clubs across two states were randomly allocated to either a neuromuscular control (NMC) (intervention n=679 players) or standard-practice (control n=885 players) exercise training programme delivered as part of regular team training sessions (2× weekly for 8-week preseason and 18-week regular-season). All game-related injuries and hours of game participation were recorded. Generalised estimating equations, adjusted for clustering (club unit), were used to compute injury incidence rates (IIRs) for all injuries, lower limb injuries (LLIs) and knee injuries sustained during games. The IIRs were compared across groups with cluster-adjusted Injury Rate Ratios (IRRs). RESULTS: Overall, 773 game injuries were recorded. The lower limb was the most frequent body region injured, accounting for 50% of injuries overall, 96 (12%) of which were knee injuries. The NMC players had a reduced LLI rate compared with control players (IRR: 0.78 (95% CI 0.56 to 1.08), p=0.14.) The knee IIR was also reduced for NMC compared with control players (IRR: 0.50 (95% CI 0.24 to 1.05), p=0.07). CONCLUSIONS: These intention-to-treat results indicate that positive outcomes can be achieved from targeted training programmes for reducing knee and LLI injury rates in men's community sport. While not statistically significant, reducing the knee injury rate by 50% and the LLI rate by 22% is still a clinically important outcome. Further injury reductions could be achieved with improved training attendance and participation in the programme.


Assuntos
Traumatismos em Atletas/prevenção & controle , Exercício Físico , Futebol Americano , Traumatismos do Joelho/prevenção & controle , Articulação do Joelho/fisiologia , Adulto , Traumatismos em Atletas/epidemiologia , Austrália/epidemiologia , Fenômenos Biomecânicos , Análise por Conglomerados , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Traumatismos do Joelho/epidemiologia , Masculino , Educação Física e Treinamento/métodos , Avaliação de Programas e Projetos de Saúde
17.
J Appl Biomech ; 32(1): 32-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26367081

RESUMO

Adolescent tennis players are at risk for low back pain (LBP). Recent research has demonstrated a potential mechanical etiology during serves; however, groundstrokes have also been suggested to load this region. Therefore, this study compared lumbar mechanics between players with and without a history of LBP during open and square stance tennis forehands and backhands. Nineteen elite, adolescent, male tennis players participated, 7 with a history of recurrent disabling LBP and 12 without. Differences in three-dimensional lumbar kinetics and kinematics were compared between pain/no pain groups and groundstrokes using linear mixed models (P < .01). There were no significant differences between pain/no pain groups. Relative to a right-handed player, groundstroke comparisons revealed that forehands had greater racquet velocity, greater lumbar right lateral flexion force, as well as upper lumbar extension/rightward rotation and lower lumbar right rotation/lateral flexion movements that were closer to or further beyond end of range than backhands. Backhands required upper lumbar leftward rotation that was beyond end range, while forehands did not. Given that players typically rotated near to their end of range during the backswing of both forehands and backhands, independent of pain, groundstrokes may contribute to the cumulative strain linked to LBP in tennis players.


Assuntos
Dor Lombar/fisiopatologia , Região Lombossacral/fisiopatologia , Amplitude de Movimento Articular/fisiologia , Tênis/fisiologia , Adolescente , Fenômenos Biomecânicos/fisiologia , Humanos , Imageamento Tridimensional , Masculino
18.
J Sports Sci ; 33(7): 675-86, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25358037

RESUMO

Enhancing the understanding of coordination and variability in the tennis serve may be of interest to coaches as they work with players to improve performance. The current study examined coordinated joint rotations and variability in the lower limbs, trunk, serving arm and ball location in the elite female tennis serve. Pre-pubescent, pubescent and adult players performed maximal effort flat serves while a 22-camera 500 Hz motion analysis system captured three-dimensional body kinematics. Coordinated joint rotations in the lower limbs and trunk appeared most consistent at the time players left the ground, suggesting that they coordinate the proximal elements of the kinematic chain to ensure that they leave the ground at a consistent time, in a consistent posture. Variability in the two degrees of freedom at the elbow became significantly greater closer to impact in adults, possibly illustrating the mechanical adjustments (compensation) these players employed to manage the changing impact location from serve to serve. Despite the variable ball toss, the temporal composition of the serve was highly consistent and supports previous assertions that players use the location of the ball to regulate their movement. Future work should consider these associations in other populations, while coaches may use the current findings to improve female serve performance.


Assuntos
Braço/fisiologia , Extremidade Inferior/fisiologia , Destreza Motora/fisiologia , Tênis/fisiologia , Tronco/fisiologia , Adolescente , Tornozelo/fisiologia , Desempenho Atlético/fisiologia , Fenômenos Biomecânicos , Criança , Cotovelo/fisiologia , Feminino , Humanos , Joelho/fisiologia , Movimento , Rotação , Análise e Desempenho de Tarefas , Adulto Jovem
19.
J Sports Sci ; 33(15): 1622-31, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25643181

RESUMO

This modelling study sought to describe the relationships between elbow joint kinematics and wrist joint linear velocity in cricket fast bowlers, and to assess the sensitivity of wrist velocity to systematic manipulations of empirical joint kinematic profiles. A 12-camera Vicon motion analysis system operating at 250 Hz recorded the bowling actions of 12 high performance fast bowlers. Empirical elbow joint kinematic data were entered into a cricket bowling specific "Forward Kinematic Model" and then subsequently underwent fixed angle, angular offset and angle amplification manipulations. A combination of 20° flexion and 20° abduction at the elbow was shown to maximise wrist velocity within the experimental limits. An increased elbow flexion offset manipulation elicited an increase in wrist velocity. Amplification of elbow joint flexion-extension angular displacement indicated that, contrary to previous research, elbow extension range of motion and angular velocity at the time of ball release were negatively related to wrist velocity. Some relationships between manipulated joint angular waveforms and wrist velocity were non-linear, supporting the use of a model that accounts for the non-linear relationships between execution and outcome variables in assessing the relationships between elbow joint kinematics and wrist joint velocity in cricket fast bowlers.


Assuntos
Fenômenos Biomecânicos/fisiologia , Articulação do Cotovelo/fisiologia , Modelos Biológicos , Esportes/fisiologia , Articulação do Punho/fisiologia , Humanos , Masculino , Adulto Jovem
20.
Breast Cancer Res ; 16(5): 438, 2014 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-25231728

RESUMO

INTRODUCTION: Recent evidence suggests that tumour lymphangiogenesis promotes lymph node metastasis, a major prognostic factor for survival of breast cancer patients. However, signaling mechanisms involved in tumour-induced lymphangiogenesis remain poorly understood. The expression of ezrin, a membrane cytoskeletal crosslinker and Src substrate, correlates with poor outcome in a diversity of cancers including breast. Furthermore, ezrin is essential in experimental invasion and metastasis models of breast cancer. Ezrin acts cooperatively with Src in the regulation of the Src-induced malignant phenotype and metastasis. However, it remains unclear if ezrin plays a role in Src-induced tumour angio/lymphangiogenesis. METHODS: The effects of ezrin knockdown and mutation on angio/lymphangiogenic potential of human MDA-MB-231 and mouse AC2M2 mammary carcinoma cell lines were examined in the presence of constitutively active or wild-type (WT) Src. In vitro assays using primary human lymphatic endothelial cells (hLEC), an ex vivo aortic ring assay, and in vivo tumour engraftment were utilized to assess angio/lymphangiogenic activity of cancer cells. RESULTS: Ezrin-deficient cells expressing activated Src displayed significant reduction in endothelial cell branching in the aortic ring assay in addition to reduced hLEC migration, tube formation, and permeability compared to the controls. Intravital imaging and microvessel density (MVD) analysis of tumour xenografts revealed significant reductions in tumour-induced angio/lymphangiogenesis in ezrin-deficient cells when compared to the WT or activated Src-expressing cells. Moreover, syngeneic tumours derived from ezrin-deficient or Y477F ezrin-expressing (non-phosphorylatable by Src) AC2M2 cells further confirmed the xenograft results. Immunoblotting analysis provided a link between ezrin expression and a key angio/lymphangiogenesis signaling pathway by revealing that ezrin regulates Stat3 activation, VEGF-A/-C and IL-6 expression in breast cancer cell lines. Furthermore, high expression of ezrin in human breast tumours significantly correlated with elevated Src expression and the presence of lymphovascular invasion. CONCLUSIONS: The results describe a novel function for ezrin in the regulation of tumour-induced angio/lymphangiogenesis promoted by Src in breast cancer. The combination of Src/ezrin might prove to be a beneficial prognostic/predictive biomarker for early-stage metastatic breast cancer.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas do Citoesqueleto/fisiologia , Linfangiogênese , Neovascularização Patológica/metabolismo , Animais , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/patologia , Feminino , Humanos , Interleucina-6/metabolismo , Camundongos Endogâmicos CBA , Camundongos Knockout , Mutação de Sentido Incorreto , Invasividade Neoplásica , Transplante de Neoplasias , Fosforilação , Processamento de Proteína Pós-Traducional , Ratos Sprague-Dawley , Fator de Transcrição STAT3/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator C de Crescimento do Endotélio Vascular/metabolismo , Quinases da Família src
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA