Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 216
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
J Biol Chem ; 299(5): 104699, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37059179

RESUMO

The receptor tyrosine kinase ephrin type-A receptor 2 (EphA2) is overexpressed in malignant tumors. We previously reported that non-canonical EphA2 phosphorylation at Ser-897 was catalyzed by p90 ribosomal S6 kinase (RSK) via the MEK-ERK pathway in ligand- and tyrosine kinase-independent manners. Non-canonical EphA2 activation plays a key role in tumor progression; however, its activation mechanism remains unclear. In the present study, we focused on cellular stress signaling as a novel inducer of non-canonical EphA2 activation. p38, instead of ERK in the case of epidermal growth factor signaling, activated RSK-EphA2 under cellular stress conditions, including anisomycin, cisplatin, and high osmotic stress. Notably, p38 activated the RSK-EphA2 axis via downstream MAPK-activated protein kinase 2 (MK2). Furthermore, MK2 directly phosphorylated both RSK1 Ser-380 and RSK2 Ser-386, critical residues for the activation of their N-terminal kinases, which is consistent with the result showing that the C-terminal kinase domain of RSK1 was dispensable for MK2-mediated EphA2 phosphorylation. Moreover, the p38-MK2-RSK-EphA2 axis promoted glioblastoma cell migration induced by temozolomide, a chemotherapeutic agent for the treatment of glioblastoma patients. Collectively, the present results reveal a novel molecular mechanism for non-canonical EphA2 activation under stress conditions in the tumor microenvironment.


Assuntos
Glioblastoma , Receptor EphA2 , Transdução de Sinais , Humanos , Anisomicina/farmacologia , Movimento Celular , Cisplatino/farmacologia , Sistema de Sinalização das MAP Quinases/fisiologia , Pressão Osmótica , Fosforilação , Receptores Proteína Tirosina Quinases/metabolismo , Receptor EphA2/metabolismo , Proteínas Quinases S6 Ribossômicas 90-kDa/genética , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Microambiente Tumoral
2.
Biol Pharm Bull ; 47(5): 895-903, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38692865

RESUMO

Epidermal growth factor (EGF)-EGF receptor (EGFR) signaling studies paved the way for a basic understanding of growth factor and oncogene signaling pathways and the development of tyrosine kinase inhibitors (TKIs). Due to resistance mutations and the activation of alternative pathways when cancer cells escape TKIs, highly diverse cell populations form in recurrent tumors through mechanisms that have not yet been fully elucidated. In this review, we summarize recent advances in EGFR basic research on signaling networks and intracellular trafficking that may clarify the novel mechanisms of inhibitor resistance, discuss recent clinical developments in EGFR-targeted cancer therapy, and offer novel strategies for cancer drug development.


Assuntos
Antineoplásicos , Receptores ErbB , Neoplasias , Inibidores de Proteínas Quinases , Transdução de Sinais , Humanos , Receptores ErbB/metabolismo , Receptores ErbB/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Transdução de Sinais/efeitos dos fármacos , Inibidores de Proteínas Quinases/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/farmacologia , Animais , Resistencia a Medicamentos Antineoplásicos , Terapia de Alvo Molecular/métodos
3.
Org Biomol Chem ; 21(22): 4656-4660, 2023 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-37212260

RESUMO

Tuning the electrophilicities of Michael acceptors is important for the development of targeted covalent drugs. To this end, the electronic effects of electrophilic structures have been well investigated, but not the steric effects. In this work, we synthesized ten α-methylene cyclopentanones (MCPs), screened them for NF-κB inhibitory activity, and analyzed their conformations. We found that MCP-4b, MCP-5b, and MCP-6b are novel NF-κB inhibitors, whereas the corresponding diastereomers MCP-4a, MCP-5a, and MCP-6a are inactive. Conformational analysis suggested that the stereochemistry of the side chain (R) on MCPs dictates the stable conformation of the core bicyclic 5/6 ring system. The conformational preference seemed to influence their reactivity toward nucleophiles. Consequently, a thiol reactivity assay showed that MCP-5b has higher reactivity than MCP-5a. The results indicate that the conformational switching of MCPs may control reactivity and bioactivity in the presence of steric effects.


Assuntos
Ciclopentanos , NF-kappa B , Conformação Molecular , Ciclopentanos/farmacologia , Compostos de Sulfidrila/química , Quimiocina CCL2
4.
Biol Pharm Bull ; 45(2): 162-168, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35110502

RESUMO

The long-term administration of tamoxifen to estrogen receptor α (ERα)-positive breast cancer patients is an established treatment that reduces mortality and recurrence. However, resistance to tamoxifen and an increased risk of endometrial cancer may occur; therefore, the mechanisms by which tamoxifen causes these adverse effects warrant further study. Tamoxifen has been shown to activate mitogen-activated protein kinase (MAPK) in an ERα-independent manner; therefore, we investigated its effects on the MAPK-mediated non-canonical activation of EphA2, a critical event regulating cell migration. Tamoxifen at slightly higher concentrations induced the rapid phosphorylation of EphA2 at Ser-897 via the MAPK/extracellular signal-regulated kinase (ERK) kinase (MEK)-ERK-ribosomal S6 kinases (RSK) pathway in HeLa cells. In addition, tamoxifen significantly enhanced the migration ability of ERα-negative MDA-MB-231 breast cancer cells in RSK- and EphA2-dependent manners. Phosphorylated EphA2 was internalized and re-localized to the plasma membrane, including lamellipodia, in an RSK-dependent manner. Collectively, the present results provide novel insights into the tumor-promoting activity of tamoxifen.


Assuntos
Antineoplásicos Hormonais/farmacologia , Neoplasias da Mama/metabolismo , Receptor EphA2/metabolismo , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Tamoxifeno/farmacologia , Linhagem Celular Tumoral , Movimento Celular , Receptor alfa de Estrogênio , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Fosforilação , Receptor EphA2/genética , Proteínas Quinases S6 Ribossômicas 90-kDa/genética
5.
Biol Pharm Bull ; 45(10): 1553-1558, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36184515

RESUMO

9,10-Phenanthrenequinone (9,10-PQ), a polycyclic aromatic hydrocarbon that is present in air pollutants, such as diesel exhaust gas and PM2.5, causes the production of excess reactive oxygen species. 9,10-PQ was recently shown to induce the activation of epidermal growth factor receptor (EGFR) by inhibiting protein tyrosine phosphatase 1B. In the present study, we focused on the non-canonical regulation of EGFR, including negative feedback and internalization. In contrast to previous findings, 9,10-PQ inhibited the constitutive tyrosine phosphorylation of EGFR via the mitogen-activated protein extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK)-mediated phosphorylation of Thr-669 in EGFR-overexpressing A431 and MDA-MB-468 cells. In addition, 9,10-PQ induced the clathrin-mediated endocytosis of EGFR via the p38 phosphorylation of Ser-1015 in HeLa and A549 cells. These results revealed that 9,10-PQ strongly induced the non-canonical regulation of EGFR by activating mitogen-activated protein kinase (MAPK).


Assuntos
Poluentes Atmosféricos , Fenantrenos , Poluentes Atmosféricos/toxicidade , Clatrina/metabolismo , Receptores ErbB/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mitógenos , Material Particulado , Fenantrenos/farmacologia , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Espécies Reativas de Oxigênio/metabolismo , Tirosina/metabolismo , Emissões de Veículos
6.
J Stroke Cerebrovasc Dis ; 31(1): 106169, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34735899

RESUMO

OBJECTIVES: To examine the relationship between patients' transfer ability and fall risk in stroke patients during hospitalization. MATERIALS AND METHODS: We retrospectively enrolled 237 stroke patients who were transferred to a convalescent rehabilitation ward from acute wards in the same hospital. Using incident reports, we investigated their fall rates and activity status at the falls according to their transfer abilities, which were assessed with Functional Independence Measure (FIM) transfer scores. The bi-weekly time trend of fall rates in all patients and in three subgroups based on FIM transfer scores of 1-3, 4-5, and 6-7, and activity status at the falls, were investigated. In addition, changes of patients' transfer ability on admission, at the first fall, and at discharge were investigated among falling patients. RESULTS: The fall rate was the greatest in patients with a FIM transfer score of 4 (14.3 times/1000 person-days). The majority of falls for patients with a FIM transfer score of 1 occurred at the activity status of "on the bed" and "sitting", while three quarters of patients with a FIM score of 7 had falls during "standing" and "walking". No longitudinal trend in fall rates was found overall; however, the fall rate trends differed depending on the FIM transfer score. The majority of the patients who fell required full assistance for transfers upon admission but required no assistance at discharge. CONCLUSIONS: Fall risk differed among patients with various transfer abilities; the greatest risk was in those who needed minimal assistance for transfers.


Assuntos
Acidentes por Quedas , Estado Funcional , Transferência de Pacientes , Acidente Vascular Cerebral , Humanos , Alta do Paciente , Estudos Retrospectivos , Medição de Risco , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapia , Reabilitação do Acidente Vascular Cerebral
7.
Biol Pharm Bull ; 44(11): 1681-1687, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34719645

RESUMO

The ligand-induced internalization of epidermal growth factor receptor (EGFR) is generally considered to attenuate downstream signaling via its endosomal degradation. However, the endocytosis of an oncogenic EGFR variant III (EGFRvIII) is impaired, which leads to persistent signaling from the cell surface, thereby promoting the proliferation and survival of glioblastoma multiforme (GBM) cells. Cellular stress triggers the non-canonical endocytosis-recycling of EGFR by p38-mediated phosphorylation. In the present study, we used temozolomide (TMZ), the standard chemotherapeutic agent for the treatment of GBM patients, to examine whether EGFRvIII is controlled by a non-canonical mechanism. TMZ triggered the endocytic trafficking of serine phosphorylated EGFRvIII. Moreover, phosphorylation and endocytosis were abrogated by the selective p38 inhibitor SB203580, but not gefitinib, indicating that EGFRvIII is recruited to p38-mediated non-canonical endocytosis. The combination of TMZ and SB203580 also showed potential inhibitory effects on the proliferation and motility of glioblastoma cells.


Assuntos
Antineoplásicos/farmacologia , Endocitose/efeitos dos fármacos , Receptores ErbB/metabolismo , Glioblastoma/tratamento farmacológico , Temozolomida/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Anisomicina/farmacologia , Western Blotting , Linhagem Celular Tumoral , Eletroforese em Gel de Poliacrilamida , Imunofluorescência , Glioblastoma/metabolismo , Humanos , Fosforilação/efeitos dos fármacos
8.
Somatosens Mot Res ; 37(1): 1-5, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31771387

RESUMO

Purpose/aim of the study: An increase of hip abductor muscle strength contributes to the increase in gait speed. It is known that the rate of force development (RFD), an indicator of muscle strength, is increased by the combined use of low-intensity neuromuscular electrical stimulation (NMES) to the glutaeus medius (GM) and low-load resistance training (RT). However, it is unclear whether low-intensity neuromuscular electrical stimulation of the glutaeus medius during walking also increases the rate of force development. The aim of this study was to clarify whether NMES to the GM during gait modulates the RFD of the hip abductor muscles in healthy adults.Materials and methods: Twenty-two healthy adults randomly received both gait with sub-motor threshold NMES and gait with sham NMES conditions. The RFD was assessed at pre- and post-intervention. A two-way repeated measures analysis of variance was used to analyse the effects of time and intervention.Results: Gait with sub-motor threshold NMES condition significantly increased the RFD in shorter time interval (0-50 and 0-100 ms) compared to gait with sham NMES condition.Conclusions: These findings suggest that the adding low-intensity NMES of the GM to gait is effective in increasing the RFD of the hip abductor muscles.


Assuntos
Fenômenos Biomecânicos/fisiologia , Marcha/fisiologia , Quadril/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto , Estimulação Elétrica , Feminino , Humanos , Masculino , Adulto Jovem
9.
J Biol Chem ; 293(7): 2288-2301, 2018 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-29255092

RESUMO

The canonical description of transmembrane receptor function is initial binding of ligand, followed by initiation of intracellular signaling and then internalization en route to degradation or recycling to the cell surface. It is known that low concentrations of extracellular ligand lead to a higher proportion of receptor that is recycled and that non-canonical mechanisms of receptor activation, including phosphorylation by the kinase p38, can induce internalization and recycling. However, no connections have been made between these pathways; i.e. it has yet to be established what happens to unbound receptors following stimulation with ligand. Here we demonstrate that a minimal level of activation of epidermal growth factor receptor (EGFR) tyrosine kinase by low levels of ligand is sufficient to fully activate downstream mitogen-activated protein kinase (MAPK) pathways, with most of the remaining unbound EGFR molecules being efficiently phosphorylated at intracellular serine/threonine residues by activated mitogen-activated protein kinase. This non-canonical, p38-mediated phosphorylation of the C-tail of EGFR, near Ser-1015, induces the clathrin-mediated endocytosis of the unliganded EGFR monomers, which occurs slightly later than the canonical endocytosis of ligand-bound EGFR dimers via tyrosine autophosphorylation. EGFR endocytosed via the non-canonical pathway is largely recycled back to the plasma membrane as functional receptors, whereas p38-independent populations are mainly sorted for lysosomal degradation. Moreover, ligand concentrations balance these endocytic trafficking pathways. These results demonstrate that ligand-activated EGFR signaling controls unliganded receptors through feedback phosphorylation, identifying a dual-mode regulation of the endocytic trafficking dynamics of EGFR.


Assuntos
Fator de Crescimento Epidérmico , Receptores ErbB , Proteínas Quinases p38 Ativadas por Mitógeno , Motivos de Aminoácidos , Dimerização , Endocitose , Ativação Enzimática , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB/química , Receptores ErbB/genética , Receptores ErbB/metabolismo , Humanos , Ligantes , Lisossomos/enzimologia , Lisossomos/genética , Fosforilação , Ligação Proteica , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
10.
Biochem Biophys Res Commun ; 514(2): 456-461, 2019 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-31053301

RESUMO

ErbB4 receptor tyrosine kinase has four different isoforms that are classified based on variants in the extracellular juxtamembrane domain (JM-a and JM-b) and the C-terminal region (CYT-1 and CYT-2). Here, we used the JM-b/CYT-1 isoform to investigate the roles of serine/threonine phosphorylation in MEK-ERK-dependent feedback inhibition. TPA as an activator of the ERK pathway markedly induced ErbB4 phosphorylation at Thr-674, the conserved common feedback site in the intracellular JM domain, which resulted in the downregulation of tyrosine autophosphorylation. We also identified Ser-1026 as an ErbB4-specific ERK target site in the CYT-1 region. Moreover, double mutations (Thr-674/Ser-1026 to Ala) significantly upregulated ErbB4 activation, indicating that Thr-674 and Ser-1026 are cooperatively involved in negative feedback regulation. Given the fact that ErbB4 mutation is one of the most common genetic alterations in melanoma cells, we demonstrated that a typical oncogenic ErbB4 mutant was resistant to the negative feedback regulation to maintain a highly active status of tyrosine kinase activity. Together, these findings indicate that feedback mechanisms are key switches determining oncogenic potentials of ErbB receptor kinases.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Retroalimentação Fisiológica , Receptor ErbB-4/química , Receptor ErbB-4/metabolismo , Sequência de Aminoácidos , Células HEK293 , Humanos , Isoenzimas/química , Isoenzimas/metabolismo , Melanoma/genética , Mutação , Fosforilação , Fosfosserina/química , Fosfosserina/metabolismo , Fosfotreonina/química , Fosfotreonina/metabolismo , Receptor ErbB-4/genética
11.
J Hand Ther ; 32(4): 519-524, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30025843

RESUMO

STUDY DESIGN: Single case report. INTRODUCTION: A previous study clarified that spasticity and motor function were improved by combined treatment with botulinum toxin type A (BTX) injection and 1-Hz repetitive transcranial magnetic stimulation (rTMS) with intensive motor training at 4 weeks after injection. However, it is not clear whether 1-Hz rTMS with intensive motor training immediately after BTX injection also improves spasticity and motor function in stroke patients. PURPOSE OF THE CASE REPORT: The purpose of this case report is to test the short- and long-term effects of BTX injection and rTMS with intensive motor training on the spasticity, motor function, and usefulness of the paretic hand in a stroke patient. METHODS: A 64-year-old male, who suffered from a right cerebral hemorrhage 53 months previously, participated in the present study. BTX was injected into the spastic muscles of the affected upper limb. He then received the new protocol for a total of 24 sessions. The Modified Ashworth Scale (MAS), Fugl-Meyer Assessment (FMA), and Motor Activity Log, consisting of the amount of use and quality of movement scales, were assessed before and immediately after BTX injection, at discharge, and monthly for up to 5 months after discharge. RESULTS: For the short-term effects of the therapy, the MAS scores of the elbow and wrist, FMA score, and quality of movement score improved. For the long-term effects of the therapy, the MAS score of the fingers, FMA score, and amount of use score improved for up to 5 months after discharge. CONCLUSIONS: The present case report showed the improvement of all assessments performed in the short and/or long term and suggest the possibility of shortening the intervention period of combined therapy of BTX and rTMS with intensive motor training.


Assuntos
Toxinas Botulínicas Tipo A/uso terapêutico , Espasticidade Muscular/terapia , Reabilitação do Acidente Vascular Cerebral/métodos , Estimulação Magnética Transcraniana , Extremidade Superior/fisiopatologia , Terapia Combinada , Humanos , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Espasticidade Muscular/fisiopatologia , Fármacos Neuromusculares/uso terapêutico , Acidente Vascular Cerebral/fisiopatologia
12.
Cancer Sci ; 108(5): 1071-1079, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28256087

RESUMO

Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell lymphoma subtype, and the Epstein-Barr virus (EBV)-positive subtype of DLBCL is known to show a more aggressive clinical behavior than the EBV-negative one. BTB and CNC homology 2 (BACH2) has been highlighted as a tumor suppressor in hematopoietic malignancies; however, the role of BACH2 in EBV-positive DLBCL is unclear. In the present study, BACH2 expression and its significance were studied in 23 EBV-positive and 43 EBV-negative patient samples. Immunohistochemistry revealed BACH2 downregulation in EBV-positive cases (P < 0.0001), although biallelic deletion of BACH2 was not detected by FISH. Next, we analyzed the contribution of BACH2 negativity to aggressiveness in EBV-positive B-cell lymphomas using FL-18 (EBV-negative) and FL-18-EB cells (FL-18 sister cell line, EBV-positive). In BACH2-transfected FL-18-EB cells, downregulation of phosphorylated transforming growth factor-ß-activated kinase 1 (pTAK1) and suppression in p65 nuclear fractions were observed by Western blot analysis contrary to non-transfected FL-18-EB cells. In patient samples, pTAK1 expression and significant nuclear p65, p50, and p52 localization were detected immunohistochemically in BACH2-negative DLBCL (P < 0.0001, P = 0.006, and P = 0.001, respectively), suggesting that BACH2 downregulation contributes to constitutive activation of the nuclear factor-κB pathway through TAK1 phosphorylation in BACH2-negative DLBCL (most EBV-positive cases). Although further molecular and pathological studies are warranted to clarify the detailed mechanisms, downregulation of BACH2 may contribute to constitutive activation of the nuclear factor-κB pathway through TAK1 activation.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Regulação para Baixo/fisiologia , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/virologia , Feminino , Herpesvirus Humano 4/patogenicidade , Humanos , Imuno-Histoquímica/métodos , MAP Quinase Quinase Quinases/metabolismo , Masculino , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Fator de Transcrição RelA/metabolismo , Adulto Jovem
13.
Int J Hyperthermia ; 33(4): 411-418, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28111999

RESUMO

PURPOSE: Transforming growth factor-ß-activated kinase1 (TAK1) plays an anti-apoptotic role in response to multiple stresses. TAK1 inhibitor, 5Z-7-oxozeaenol (OZ) has been studied for its apoptotic effects. However, the combined effect of OZ with physical stresses remains to be elusive. Therefore, in this study we focussed to determine the combined effects of OZ with hyperthermia (HT) using Molt-4 cell line. MATERIALS AND METHODS: Molt-4 cells were pre-treated with OZ for 1 h followed by heat exposure (44 °C, 10 min) and harvested 24 h after incubation at 37 °C, apoptosis was measured by Annexin V-FITC/PI double staining assay using flow cytometry and cell growth was observed by cell counting assay. Further mechanism involved in the combination was investigated by measuring mitochondrial membrane potential (MMP), intracellular ROS generation, expression of apoptosis related protein, intracellular calcium ion level and Fas activity. RESULTS: Combination of OZ with HT significantly enhances MMP loss and superoxide generation. Furthermore, OZ pre-treatment promotes caspase-8 cleavage, Fas externalisation, caspase 3 activity and intracellular calcium ion levels. OZ pre-treatment decreased the expression of HT-induced Bcl-2 and increased the expression of pro-apoptotic Bax, while markedly suppressed the phosphorylation of JNK and p38. In addition, increased expression of CHOP following combined treatment indicates that ER stress may also involve in the enhancement of HT-induced apoptosis. CONCLUSION: Our data showed for the first time that OZ sensitizes Molt-4 cells to HT-induced apoptosis via extrinsic and intrinsic apoptotic pathways. Furthermore, ROS and ER stress may also play role in the enhancement of HT-induced apoptosis by OZ.

14.
Somatosens Mot Res ; 34(1): 52-57, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28270048

RESUMO

This study investigated the influence of stimulus conditions of transcutaneous electrical nerve stimulation (TENS) on disynaptic reciprocal Ia inhibition (RI) and presynaptic inhibition (D1 inhibition) in healthy adults. Eight healthy participants received TENS (stimulus frequencies of 50, 100, and 200 Hz) over the deep peroneal nerve and tibialis anterior (TA) muscle in the resting condition for 30 min. At pre- and post-intervention, the RI from the TA to the soleus (SOL) and D1 inhibition of the SOL alpha motor neuron were assessed by evoked electromyography. The results showed that RI was not changed by TENS at any stimulus frequency condition. Conversely, D1 inhibition was significantly changed by TENS regardless of the stimulus frequency. The present results and previous studies pertaining to RI suggest that the resting condition might strongly influence the lack of pre- vs. post-intervention change in the RI. Regarding the D1 inhibition, the present results suggest that the effect of TENS might be caused by post-tetanic potentiation. The knowledge gained from the present study might contribute to a better understanding of fundamental studies of TENS in healthy adults and its clinical application for stroke survivors.


Assuntos
Músculo Esquelético/fisiologia , Inibição Neural/fisiologia , Estimulação Elétrica Nervosa Transcutânea , Adulto , Análise de Variância , Fenômenos Biofísicos/fisiologia , Eletromiografia , Feminino , Reflexo H/fisiologia , Voluntários Saudáveis , Humanos , Masculino , Adulto Jovem
15.
Biol Pharm Bull ; 40(10): 1616-1624, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28966234

RESUMO

Erythropoietin-producing hepatocellular receptor A2 (EphA2) receptor tyrosine kinase controls multiple physiological processes to maintain homeostasis in normal cells. In many types of solid tumors, it has been reported that EphA2 is overexpressed and plays a critical role in oncogenic signaling. However, in recent years, the opposing functions of EphA2 have been explained by the canonical and noncanonical signaling pathways. Ligand- and tyrosine kinase-dependent EphA2 activation (the canonical pathway) inhibits cancer cell proliferation and motility. In contrast, ligand- and tyrosine kinase-independent EphA2 signaling (the noncanonical pathway) promotes tumor survival and metastasis and controls acquired drug resistance and maintenance of cancer stem cell-like properties. Evidence has accumulated showing that the EphA2 noncanonical pathway is mainly regulated by inflammatory cytokines and growth factors via phosphorylation at Ser-897 in the intracellular C-tail region via some serine/threonine kinases, including p90 ribosomal S6 kinase. In this review, we focus on the regulation of Ser-897 phosphorylation and its functional importance in tumor malignancy and discuss future therapeutic targeting.


Assuntos
Neoplasias/metabolismo , Receptor EphA2/metabolismo , Animais , Progressão da Doença , Humanos , Receptor EphA2/química , Transdução de Sinais
16.
J Phys Ther Sci ; 29(11): 2013-2017, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29200647

RESUMO

[Purpose] To create a regression formula in order to estimate 1RM for knee extensors, based on the maximal isometric muscle strength measured using a hand-held dynamometer and data regarding the body composition. [Subjects and Methods] Measurement was performed in 21 healthy males in their twenties to thirties. Single regression analysis was performed, with measurement values representing 1RM and the maximal isometric muscle strength as dependent and independent variables, respectively. Furthermore, multiple regression analysis was performed, with data regarding the body composition incorporated as another independent variable, in addition to the maximal isometric muscle strength. [Results] Through single regression analysis with the maximal isometric muscle strength as an independent variable, the following regression formula was created: 1RM (kg)=0.714 + 0.783 × maximal isometric muscle strength (kgf). On multiple regression analysis, only the total muscle mass was extracted. [Conclusion] A highly accurate regression formula to estimate 1RM was created based on both the maximal isometric muscle strength and body composition. Using a hand-held dynamometer and body composition analyzer, it was possible to measure these items in a short time, and obtain clinically useful results.

17.
Cancer Sci ; 107(10): 1416-1421, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27403934

RESUMO

Although the secretory matricellular protein connective tissue growth factor (CTGF) has been reported to be related to lung cancer metastasis, the precise mechanism by which CTGF regulates lung cancer metastasis has not been elucidated. In the present study, we show the molecular link between CTGF secretion and the p38 pathway in the invasive and metastatic potential of non-small-cell lung cancer (NSCLC). Among three different human NSCLC cell lines (PC-14, A549, and PC-9), their in vitro invasiveness was inversely correlated with the level of CTGF secretion. By supplementing or reducing CTGF secretion in NSCLC culture, dysregulation of the invasive and metastatic potential of NSCLC cell lines was largely compensated. By focusing on the protein kinases that are known to be regulated by CTGF, we found that the p38 pathway is a key downstream signal of CTGF to regulate the metastatic potential of NSCLC. Importantly, a negative correlation between CTGF and phosphorylation status of p38 was identified in The Cancer Genome Atlas lung adenocarcinoma dataset. In the context of the clinical importance of our findings, we showed that p38 inhibitor, SB203580, reduced the metastatic potential of NSCLC secreting low levels of CTGF. Collectively, our present findings indicate that the CTGF/p38 axis is a novel therapeutic target of NSCLC metastasis, particularly NSCLC secreting low levels of CTGF.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Sistema de Sinalização das MAP Quinases , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Metástase Neoplásica
18.
Somatosens Mot Res ; 33(1): 8-15, 2016 03.
Artigo em Inglês | MEDLINE | ID: mdl-26949041

RESUMO

Neurophysiological studies in healthy subjects suggest that increased spinal inhibitory reflexes from the tibialis anterior (TA) muscle to the soleus (SOL) muscle might contribute to decreased spasticity. While 50 Hz is an effective frequency for transcutaneous electrical nerve stimulation (TENS) in healthy subjects, in stroke survivors, the effects of TENS on spinal reflex circuits and its appropriate frequency are not well known. We examined the effects of different frequencies of TENS on spinal inhibitory reflexes from the TA to SOL muscle in stroke survivors. Twenty chronic stroke survivors with ankle plantar flexor spasticity received 50-, 100-, or 200-Hz TENS over the deep peroneal nerve (DPN) of the affected lower limb for 30 min. Before and immediately after TENS, reciprocal Ia inhibition (RI) and presynaptic inhibition of the SOL alpha motor neuron (D1 inhibition) were assessed by adjusting the unconditioned H-reflex amplitude. Furthermore, during TENS, the time courses of spinal excitability and spinal inhibitory reflexes were assessed via the H-reflex, RI, and D1 inhibition. None of the TENS protocols affected mean RI, whereas D1 inhibition improved significantly following 200-Hz TENS. In a time-series comparison during TENS, repeated stimulation did not produce significant changes in the H-reflex, RI, or D1 inhibition regardless of frequency. These results suggest that the frequency-dependent effect of TENS on spinal reflexes only becomes apparent when RI and D1 inhibition are measured by adjusting the amplitude of the unconditioned H-reflex. However, 200-Hz TENS led to plasticity of synaptic transmission from the antagonist to spastic muscles in stroke survivors.


Assuntos
Espasticidade Muscular/etiologia , Espasticidade Muscular/terapia , Inibição Neural/fisiologia , Reflexo/fisiologia , Acidente Vascular Cerebral/complicações , Estimulação Elétrica Nervosa Transcutânea/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético , Acidente Vascular Cerebral/mortalidade , Acidente Vascular Cerebral/terapia , Sobreviventes
19.
J Strength Cond Res ; 30(4): 980-8, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26382131

RESUMO

We aimed to investigate whether a linear regression formula based on the relationship between joint torque and angular velocity measured using a high-speed video camera and image measurement software is effective for estimating 1 repetition maximum (1RM) and isometric peak torque in knee extension. Subjects comprised 20 healthy men (mean ± SD; age, 27.4 ± 4.9 years; height, 170.3 ± 4.4 cm; and body weight, 66.1 ± 10.9 kg). The exercise load ranged from 40% to 150% 1RM. Peak angular velocity (PAV) and peak torque were used to estimate 1RM and isometric peak torque. To elucidate the relationship between force and velocity in knee extension, the relationship between the relative proportion of 1RM (% 1RM) and PAV was examined using simple regression analysis. The concordance rate between the estimated value and actual measurement of 1RM and isometric peak torque was examined using intraclass correlation coefficients (ICCs). Reliability of the regression line of PAV and % 1RM was 0.95. The concordance rate between the actual measurement and estimated value of 1RM resulted in an ICC(2,1) of 0.93 and that of isometric peak torque had an ICC(2,1) of 0.87 and 0.86 for 6 and 3 levels of load, respectively. Our method for estimating 1RM was effective for decreasing the measurement time and reducing patients' burden. Additionally, isometric peak torque can be estimated using 3 levels of load, as we obtained the same results as those reported previously. We plan to expand the range of subjects and examine the generalizability of our results.


Assuntos
Teste de Esforço/estatística & dados numéricos , Articulação do Joelho/fisiologia , Força Muscular , Músculo Quadríceps/fisiologia , Torque , Adulto , Humanos , Contração Isométrica , Modelos Lineares , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
20.
J Phys Ther Sci ; 28(1): 134-41, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26957745

RESUMO

[Purpose] This study examined the contents of supervision needed by novice therapists to develop clinical abilities, focusing on their clinical experience and using an original evaluation table. [Subjects and Methods] An evaluation of clinical abilities basic attitudes, therapeutic skills, and clinical practice-related thoughts was conducted in 29, 21, and 9 therapists with clinical experience of 0-1 (1 year group), 1-2 (2 years group), and 2-3 (3 years group) years, respectively. [Results] There were no significant differences among the 3 groups in basic attitudes. Therapeutic skills markedly varied between the 1 and 3 years groups. In clinical practice-related thoughts, significant differences were observed between the 1 and 3 years groups and between the 2 and 3 years groups. [Conclusion] It may be appropriate for educators to provide technical education regarding skills that are achievable for students in the early stages in consideration of applied movements. Also, education for novices should be provided with importance attached to abilities influenced by clinical experience.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA