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1.
PLoS One ; 15(6): e0235270, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32589657

RESUMO

Growth hormone (GH) activates multiple signal transduction pathways. To investigate these pathways, we identified novel genes whose transcription was induced by GH in the liver of hypophysectomized (HPX) rats using the suppression subtractive hybridization technique. We found that regulator of calcineurin 1 (Rcan1) mRNA was upregulated by GH administration. RCAN1 regulates the activity of calcineurin, a Ca/calmodulin-dependent phosphatase. Rcan1 encodes two major transcripts, Rcan1-1 and Rcan1-4, resulting from differential promoter use and first exon choice. We found that a single injection of GH increased the levels of Rcan1-4 mRNA and RCAN1-4 protein transiently, but did not increase Rcan1-1 mRNA in HPX rat liver. Then the molecular mechanism of GH to induce Rcan1-4 transcription was examined in rat hepatoma H4IIE cells. Experiments using inhibitors suggested that c-JUN N-terminal kinase was required for the induction of Rcan1-4 mRNA by GH. GH increased the levels of phosphorylated c-JUN protein and c-Jun mRNA in HPX rat liver. The luciferase and electrophoretic mobility shift assays showed that c-JUN upregulated Rcan1-4 mRNA by binding to the cAMP-responsive element in the upstream of Rcan1 exon 4. These results indicate that GH activates c-JUN to affect the activity of calcineurin by the induction of Rcan1-4 in rat liver.


Assuntos
Hormônio do Crescimento/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , RNA Mensageiro/genética , Ratos , Transdução de Sinais/efeitos dos fármacos
2.
Endocr J ; 67(2): 185-200, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-31748431

RESUMO

Growth hormone (GH) has multiple physiological roles, acting on many organs. In order to investigate its roles in rat liver, we tried to identify novel genes whose transcription was regulated by GH. We identified X-box binding protein 1 (Xbp1) as a candidate gene. XBP1 is a key transcription factor activated in response to endoplasmic reticulum (ER) stress. The purpose of this study was to investigate the mode of action of GH on XBP1, including the relation with ER stress, sex-dependent expression of the mRNA, and the signaling pathway. Intravenous administration of GH rapidly and transiently increased Xbp1 mRNA in hypophysectomized rat livers. Neither phosphorylated inositol-requiring-1α (IRE1α) nor phosphorylated PKR-like ER kinase (PERK) increased, suggesting that Xbp1 expression is induced by an ER stress-independent mechanism. The active form of XBP1(S) protein was increased by GH administration and was followed by an increased ER-associated dnaJ protein 4 (ERdj4) mRNA level. XBP1(S) protein levels were predominantly identified in male rat livers with variations among individuals similar to those of phosphorylated signal transducer and activator of transcription 5B (STAT5B), suggesting that XBP1(S) protein levels are regulated by the sex-dependent secretary pattern of GH. The GH signaling pathway to induce Xbp1 mRNA was examined in rat hepatoma H4IIE cells. GH induced the phosphorylation of CCAAT/enhancer-binding protein ß (C/EBPß) following extracellular signal-regulated protein kinase (ERK) phosphorylation. Taken together, the results indicated that XBP1 is activated by GH in rat liver in a sexually dimorphic manner via ERK and C/EBPß pathway.


Assuntos
Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Hormônio do Crescimento/farmacologia , Fígado/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases , RNA Mensageiro/efeitos dos fármacos , Proteína 1 de Ligação a X-Box/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático/genética , Endorribonucleases/efeitos dos fármacos , Endorribonucleases/metabolismo , Proteínas de Choque Térmico HSP40/efeitos dos fármacos , Proteínas de Choque Térmico HSP40/genética , Hipofisectomia , Fígado/metabolismo , Complexos Multienzimáticos/efeitos dos fármacos , Complexos Multienzimáticos/metabolismo , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/metabolismo , RNA Mensageiro/metabolismo , Ratos , Fator de Transcrição STAT5/efeitos dos fármacos , Fator de Transcrição STAT5/metabolismo , Caracteres Sexuais , Transdução de Sinais , Proteína 1 de Ligação a X-Box/genética , eIF-2 Quinase/efeitos dos fármacos , eIF-2 Quinase/metabolismo
3.
J Immunother Cancer ; 7(1): 219, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412935

RESUMO

BACKGROUND: Erythropoietin-producing hepatocellular receptor A2 (EPHA2) is overexpressed on the cell surface in many cancers and predicts poor prognosis. DS-8895a is a humanized anti-EPHA2 IgG1 monoclonal antibody afucosylated to enhance antibody-dependent cellular cytotoxicity activity. We conducted a two-step, phase I, multicenter, open-label study to determine the safety, tolerability, and pharmacokinetics of DS-8895a in patients with advanced solid tumors. METHODS: Step 1 was a dose escalation cohort in advanced solid tumor patients (six dose levels, 0.1-20 mg/kg) to determine Step 2 dosing. Step 2 was a dose expansion cohort in EPHA2-positive esophageal and gastric cancer patients. DS-8895a was intravenously administered every 2 weeks for the duration of the study, with a 28-day period to assess dose-limiting toxicity (DLT). Safety, pharmacokinetics, tumor response, and potential biomarkers were evaluated. RESULTS: Thirty-seven patients (Step 1: 22, Step 2: 15 [9: gastric cancer, 6: esophageal cancer]) were enrolled. Although one DLT (Grade 4 platelet count decreased) was observed in Step 1 (dose level 6, 20 mg/kg), the maximum tolerated dose was not reached; the highest dose (20 mg/kg) was used in Step 2. Of the 37 patients, 24 (64.9%) experienced drug-related adverse events (AEs) including three (8.1%) with Grade ≥ 3 AEs. Infusion-related reactions occurred in 19 patients (51.4%) but were manageable. All patients discontinued the study (evident disease progression, 33; AEs, 4). Maximum and trough serum DS-8895a concentrations increased dose-dependently. One gastric cancer patient achieved partial response and 13 patients achieved stable disease. Serum inflammatory cytokines transiently increased at completion of and 4 h after the start of DS-8895a administration. The proportion of CD16-positive natural killer (NK) cells (CD3-CD56+CD16+) decreased 4 h after the start of DS-8895a administration, and the ratio of CD3-CD56+CD137+ to CD3-CD56+CD16+ cells increased on day 3. CONCLUSIONS: Twenty mg/kg DS-8895a infused intravenously every 2 weeks was generally safe and well tolerated in patients (n = 21) with advanced solid tumors. The exposure of DS-8895a seemed to increase dose-dependently and induce activated NK cells. TRIAL REGISTRATION: Phase 1 Study of DS-8895a in patients with advanced solid tumors ( NCT02004717 ; 7 November 2013 to 2 February 2017); retrospectively registered on 9 December 2013.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Efrina-A2/imunologia , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Gástricas/tratamento farmacológico , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/farmacocinética , Relação Dose-Resposta Imunológica , Neoplasias Esofágicas/imunologia , Neoplasias Esofágicas/metabolismo , Feminino , Humanos , Pessoa de Meia-Idade , Receptor EphA2 , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/metabolismo
4.
J Reprod Dev ; 60(4): 312-6, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24909600

RESUMO

Puberty is associated with an increase in gonadotropin secretion as a result of an increase in gonadotropin-releasing hormone (GnRH) secretion. Kisspeptin is considered to play a key role in puberty onset in many mammalian species, including rodents, ruminants and primates. The present study aimed to determine if changes in hypothalamic expression of the KISS1 gene, encoding kisspeptin, are associated with the onset of puberty in pigs. The animals (n=4 in each group) were perfused with 4% paraformaldehyde at 0, 1, 2, 3 and 4 months old, as prepubertal stages, and at 5 months old, as the peripubertal stage, following each blood sampling. KISS1 gene expressions in coronal sections of brains were visualized by in situ hybridization. Plasma luteinizing hormone (LH) was measured by radioimmunoassay. KISS1 mRNA signals were observed in the arcuate nucleus (ARC) at all ages examined without any significant difference in the number of KISS1-expressing cells, indicating that the KISS1 gene is constantly expressed in the ARC throughout pubertal development in pigs. The plasma LH concentration was the highest in 0-month-old piglets and significantly decreased in the 1- and 2 month-old groups (P<0.05), suggesting a developing negative feedback mechanism affecting gonadotropin release during the prepubertal period. Considering the potent stimulating effect of kisspeptin on gonadotropin release in prepubertal pigs, kisspeptin secretion rather than kisspeptin synthesis may be responsible for the onset of puberty in pigs.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Maturidade Sexual , Animais , Núcleo Arqueado do Hipotálamo/crescimento & desenvolvimento , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Kisspeptinas/genética , Hormônio Luteinizante/sangue , Ovário/crescimento & desenvolvimento , Progesterona/sangue , Suínos
5.
Clin Calcium ; 21(7): 981-91, 2011 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-21719978

RESUMO

The most recommendable MRI sequence for the morphologic assessment of the cartilage damage due to osteoarthritis (OA) is gradient echo fat suppression T1 weighted image (SPGR: Spoiled gradient recalled acquisition in the steady state, FLASH: Fast low-angle shot). For the detection of the cartilage degeneration before the morphological change, T2 mapping, dGEMRIC (delayed Gd-DTPA2-Enhanced MRI of Cartilage), and T1ρ mapping are suggested. Subchondral bone structural changes such as bone sclerosis and cyst are deeply related to the etiology of OA, and quantitative evaluation for them using MDCT (Multi-Detector row CT) and 3TMRI are suggested.


Assuntos
Osso e Ossos/patologia , Cartilagem Articular/patologia , Imageamento por Ressonância Magnética/métodos , Osteoartrite/diagnóstico , Tomografia Computadorizada Espiral , Osso e Ossos/diagnóstico por imagem , Cartilagem Articular/diagnóstico por imagem , Humanos
6.
Bone ; 48(3): 627-30, 2011 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-21087686

RESUMO

The geometry as well as bone mineral density (BMD) of the proximal femur contributes to fracture risk. How and the extent to which they change due to natural aging is not fully understood. We assessed BMD and geometry in the femoral neck and shaft separately, in 59 normal Japanese postmenopausal women aged 54-84 years, using clinical computed tomography (CT) and commercially available software, at baseline and 2-year follow-up. This system detected significant reductions over the 2-year interval in total BMD (%change/year = -0.900 ± 0.257, p < 0.0005), cortical cross-sectional area (CSA) (-0.800 ± 0.423%/year, p < 0.05) and cortical thickness (-1.120 ± 0.453%/year, p < 0.01) in the femoral neck. In the femoral shaft, cortical BMD decreased significantly (-0.642 ± 0.188%/year, p < 0.005). Regarding biomechanical parameters in the femoral neck, the cross-sectional moment of inertia (CSMI) and section modulus (SM) decreased (-1.38 ± 3.65%/year, p < 0.01 and -1.37 ± 2.96%/year, p < 0.005) and the buckling ratio (BR) increased significantly (1.48 ± 4.81%/year, p < 0.05), whereas no changes were found in the femoral shaft. The distinct patterns of age-related changes in the geometry and biomechanical properties in the femoral neck and shaft suggest that improved geometric measures are possible with the current non-invasive method using clinical CT.


Assuntos
Envelhecimento/fisiologia , Densidade Óssea/fisiologia , Fêmur/anatomia & histologia , Fêmur/diagnóstico por imagem , Quadril/anatomia & histologia , Pós-Menopausa/fisiologia , Tomografia Computadorizada por Raios X , Idoso , Fenômenos Biomecânicos/fisiologia , Demografia , Feminino , Seguimentos , Quadril/diagnóstico por imagem , Humanos , Estudos Longitudinais
7.
Planta Med ; 74(4): 413-6, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18484534

RESUMO

Four known friedelane-type triterpenoids, friedelin ( 1), 3-hydroxy-D:A-friedoolean-3-en-2-one ( 2), 2beta-hydroxy-D:A-friedooleanan-3-one ( 3), and 3alpha-hydroxy-D:A-friedooleanan-2-one ( 4), and two known lupane-type triterpenoids, lupeol ( 5) and betulin ( 6), were isolated from the stem bark of Mallotus philippensis. Isolates 1 - 4 and their synthetic analogues, 3-acetoxy-D:A-friedoolean-3-en-2-one ( 2A) and 3alpha-acetoxy-D:A-friedooleanan-2-one ( 4A), were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12- O-tetradecanoylphorbol 13-acetate (TPA). The inhibitory effect of compounds 2 (IC (50) = 292 mol ratio/32 pmol/TPA) and 4 (IC (50) = 288) was stronger than those of the other compounds tested and the positive control, curcumin (IC (50) = 343). Compound 4 strongly inhibited mouse skin tumor promotion in an IN VIVO two-stage carcinogenesis model. Studies have been conducted to identify the biologically active compounds extracted from the leaves, bark, and cones of trees that currently have no specific commercial use and are therefore treated as waste in the forestry industry.


Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Mallotus (Planta)/química , Casca de Planta/química , Triterpenos/química , Triterpenos/farmacologia , Animais , Linhagem Celular , Feminino , Herpesvirus Humano 4 , Humanos , Camundongos , Camundongos Endogâmicos ICR , Estrutura Molecular , Neoplasias Experimentais/tratamento farmacológico , Caules de Planta , Organismos Livres de Patógenos Específicos , Ativação Viral/efeitos dos fármacos
8.
J Antibiot (Tokyo) ; 60(10): 633-9, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17965479

RESUMO

In the course of our screening for inhibitors of hyaluronic acid (HA) binding to cellular receptor CD44, a novel inhibitor, F-19848 A, was isolated from the cultured broth of the fungus strain Dacrymyces sp. SANK 20204. This compound inhibited the binding of CD44 and HA with an IC50 value of 23.5 microM and CD44-dependent HA degradation was inhibited with an IC50 value of 98.6 microM in a cell-based assay. The structure was elucidated by physico-chemical properties, analysis of spectral data, and decomposition experiments.


Assuntos
Receptores de Hialuronatos/efeitos dos fármacos , Receptores de Hialuronatos/metabolismo , Ácido Hialurônico/antagonistas & inibidores , Ácido Hialurônico/metabolismo , Oligossacarídeos/síntese química , Basidiomycota/química , Basidiomycota/ultraestrutura , Ligação Competitiva/efeitos dos fármacos , Sequência de Carboidratos , Linhagem Celular , Fenômenos Químicos , Físico-Química , Ácidos Graxos/química , Fermentação , Glucose/química , Espectroscopia de Ressonância Magnética , Metilação , Dados de Sequência Molecular , Oligossacarídeos/farmacologia , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Xilose/química
9.
Bioorg Med Chem ; 15(1): 257-64, 2007 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-17049251

RESUMO

Two new lanostane-type triterpenoids, inonotsuoxides A (1) and B (2) along with three known lanostane-type triterpenoids, inotodiol (3), trametenolic acid (4), and lanosterol (5), were isolated from the sclerotia of Inonotus obliquus (Pers.: Fr.) (Japanese name: Kabanoanakake) (Russian name: Chaga). Their structures were determined to be 22R,25-epoxylanost-8-ene-3beta,24S-diol (1) and 22S,25-epoxylanost-8-ene-3beta,24S-diol (2) on the basis of spectral data including single crystal X-ray analysis. These compounds except for 2 were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), as a test for potential cancer chemopreventive agents. The most abundant triterpene, inotodiol (3), was investigated for the inhibitory effect in a two-stage carcinogenesis test on mouse skin using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter. Compound 3 was found to exhibit the potent anti-tumor promoting activity in the in vivo carcinogenesis test.


Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos/química , Basidiomycota/química , Lanosterol/análogos & derivados , Triterpenos/química , 9,10-Dimetil-1,2-benzantraceno/química , Animais , Antígenos Virais/efeitos dos fármacos , Antígenos Virais/metabolismo , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Lanosterol/química , Lanosterol/farmacologia , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/normas , Camundongos , Camundongos Endogâmicos ICR , Modelos Moleculares , Conformação Molecular , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Padrões de Referência , Estereoisomerismo , Relação Estrutura-Atividade , Acetato de Tetradecanoilforbol/química , Acetato de Tetradecanoilforbol/farmacologia , Triterpenos/isolamento & purificação , Triterpenos/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
10.
J Antibiot (Tokyo) ; 59(12): 770-6, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17323643

RESUMO

In an attempt to obtain inhibitors of hyaluronic acid (HA) binding to its receptor, CD44, we established an efficient assay method to detect and quantify binding using fluorescein-labeled HA and HEK293 cells stably expressing CD44. As a result of the screening of culture broths of microorganisms, we found fungus strain Gloeoporus dichrous SANK 30502 produced inhibitory activity in this new assay. Five compounds, F-16438 A, B, E, F and G, were isolated from the fermentation broths, and their IC50 values were determined to be 10.3, 13.5, 27.3, 12.0 and 13.0 microM, respectively. F-16438 A, B, E, F and G are the first reported inhibitors of binding HA to CD44. F-16438 A, B, E and F have novel structures.


Assuntos
Receptores de Hialuronatos/metabolismo , Ácido Hialurônico/antagonistas & inibidores , Manosídeos/farmacologia , Polyporales/metabolismo , Salicilatos/farmacologia , Linhagem Celular , Endocitose , Humanos , Ácido Hialurônico/metabolismo
11.
J Antibiot (Tokyo) ; 59(12): 777-84, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17323644

RESUMO

In the course of our screening for binding inhibitors of CD44 and hyaluronic acid, five active compounds, F-16438 A, B, E, F and G were found and isolated from the cultured broth of a fungal strain, Gloeoporus dichrous SANK 30502. The structures of these compounds except for F-16438 G were elucidated by physico-chemical and spectral data to be new compounds related to caloporoside; F-16438 G was identified to be the 6'-malonylated derivative of caloporoside.


Assuntos
Fermentação , Receptores de Hialuronatos/metabolismo , Ácido Hialurônico/antagonistas & inibidores , Manosídeos/isolamento & purificação , Polyporales/metabolismo , Salicilatos/isolamento & purificação , Ácido Hialurônico/metabolismo , Espectroscopia de Ressonância Magnética , Manosídeos/química , Conformação Molecular , Salicilatos/química
12.
Endocr J ; 51(2): 145-54, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15118263

RESUMO

The activation of the growth hormone (GH) receptor is followed by activation of the JAK2-STAT system in peripheral tissues, which in turn induces the expression of suppressors of cytokine signaling (SOCS) and/or cytokine-inducible SH2 protein (CIS) to achieve the attenuation of the signaling. To examine whether GH involves the SOCS/CIS system as intracellular negative regulators in the hypothalamus, we observed the effects of human GH on the gene expression of SOCS/CIS in the rat hypothalamus. The mRNAs of CIS, SOCS2, and SOCS3 in the hypothalamus of hypophysectomized male rats were examined by Northern analysis following the intravenous administration of recombinant human GH (hGH), 50 microg/100 g BW. The SOCS3 and CIS mRNAs were increased transiently with maximum expression at 1 h after hGH administration. The intravenous hGH did not induce SOCS2 mRNA expression in the hypothalamus. In situ hybridization demonstrated the increase of SOCS3 and CIS mRNAs in the arcuate nucleus after hGH administration, and the increase of SOCS3 mRNA in the periventricular nucleus. The hGH applied to primary cultured hypothalamic neurons at 500 ng/ml induced transient increase of SOCS3 and CIS mRNAs, but not SOCS2 mRNA. The results show that hGH acts directly on the neurons in the hypothalamus, and increases SOCS3 and CIS mRNAs, suggesting that these negative regulators may be involved in the mechanism that turns off the hGH action in the hypothalamic neurons.


Assuntos
Hormônio do Crescimento Humano/farmacologia , Hipotálamo/metabolismo , Proteínas Imediatamente Precoces/genética , Neurônios/metabolismo , RNA Mensageiro/metabolismo , Proteínas Repressoras/genética , Fatores de Transcrição/genética , Animais , Northern Blotting , Células Cultivadas , Hipofisectomia , Hibridização In Situ , Masculino , Neurônios/efeitos dos fármacos , RNA Mensageiro/efeitos dos fármacos , Ratos , Ratos Wistar , Proteínas Recombinantes/farmacologia , Proteínas Son Of Sevenless/genética , Proteína 3 Supressora da Sinalização de Citocinas , Proteínas Supressoras da Sinalização de Citocina
13.
Jpn J Ophthalmol ; 48(1): 34-6, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-14767648

RESUMO

PURPOSE: The purpose of this study was to compare the binding affinity of bunazosin and dorzolamide to synthetic melanin relative to that of timolol. METHODS: Synthetic melanin was prepared from dopa by the action of tyrosinase. Timolol, dorzolamide, and bunazosin were incubated separately at a concentration of 10(-4) M in 2 ml of 0.066 M phosphate buffer containing 5 mg of synthetic melanin. After centrifugation, the absorbance of each free drug in the supernatant was measured at its optimum wavelength. The percentage of each drug bound to melanin was calculated directly from the change in absorbance relative to the initial value. RESULTS: The increase in the binding rates of all three drugs seemed to reach a plateau after 30 min. After incubating for 60 min, the binding rate of timolol was 22.2% +/- 4.9%, bunazosin 36.3% +/- 2.5%, and dorzolamide 8.5% +/- 1.9%. There were statistically significant differences between the binding rates of each drug. CONCLUSIONS: Under our study conditions, the order of binding affinity of these ocular hypotensive agents to synthetic melanin seems to be as follows: bunazosin>timolol>dorzolamide.


Assuntos
Anti-Hipertensivos/metabolismo , Melaninas/metabolismo , Quinazolinas/metabolismo , Sulfonamidas/metabolismo , Tiofenos/metabolismo , Timolol/metabolismo , Melaninas/síntese química , Ligação Proteica
14.
Genes Chromosomes Cancer ; 35(1): 30-7, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12203787

RESUMO

A novel gene, ELKS, whose 5' portion was fused to the RET gene, was found in a papillary thyroid carcinoma. A cDNA of this gene obtained from a human-brain cDNA library revealed that it encoded a peptide of 948 amino acids, termed ELKSalpha. We identified four other isoforms, which encoded ELKSbeta, ELKSgamma, ELKSdelta, and ELKSepsilon proteins consisting, respectively, of 992, 720, 1088, and 1116 amino acid residues. Analysis of the gene structure revealed that the isoforms were generated by alternative splicing. Isoforms beta, gamma, delta, and epsilon all contain an optional exon (exon14a), but ELKSgamma, -delta, and -epsilon lack exon 1b. ELKSgamma lacks exons 3 to 6. ELKSdelta and -epsilon lack exons 12 and 17; ELKSepsilon contains an optional exon (exon 6a). Analysis by RT-PCR suggested that ELKSalpha and ELKSbeta mRNAs are abundant in the brain, ELKSdelta and ELKSepsilon mRNAs predominate in testis and thyroid, and ELKSepsilon mRNA predominates in other tissues. To prove whether the fusion of different ELKS isoforms to RET (between ELKS coiled-coil domains and the RET kinase domain) could produce chimeric proteins that could be autophosphorylated, we synthesized ELKSgamma-RET, ELKSdelta-RET, and ELKSepsilon-RET fusion proteins in vitro. Immunoblotting with anti-ELKS, anti-RET, and anti-phosphotyrosine antibodies demonstrated that the chimeric proteins were constitutively phosphorylated at tyrosine residues, whereas native RET protein was not. These results indicate that the ELKS gene is alternatively spliced, and that every type of ELKS-RET chimeric protein having oligomerization domains can activate RET's cytoplasmic tyrosine kinase.


Assuntos
Carcinoma Papilar/genética , Proteínas de Drosophila , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/biossíntese , Neoplasias da Glândula Tireoide/genética , Proteínas Adaptadoras de Transdução de Sinal , Adolescente , Adulto , Processamento Alternativo/genética , Sequência de Aminoácidos , Proteínas do Citoesqueleto , DNA de Neoplasias/genética , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Especificidade de Órgãos/genética , Fosforilação , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Estrutura Quaternária de Proteína/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-ret , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Análise de Sequência de DNA/métodos
15.
Neuroendocrinology ; 75(6): 384-91, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12065891

RESUMO

The pattern of growth hormone (GH) secretion is sexually dimorphic in rats. We have previously shown that the secretory pattern in adult ovariectomized (OVX) female rats is masculinized by the administration of a single dose of dihydrotestosterone (DHT), a nonaromatizable androgen. To investigate the primary site of action of DHT in the brain, a small amount of DHT was injected directly into a defined area of the brain, and the blood GH profile was observed for 18 h in conscious adult OVX female rats. The bilateral direct injection of 1 microg DHT into the medial preoptic area (MPA) produced a male-like secretory pattern of GH in OVX rats. The masculinizing effects became apparent at 9 h after injection, from which time the episodic GH secretion was produced regularly at intervals of about 150 min, the amplitude of the peak increased and baseline levels were lowered. These parameters, analyzed during 9-18 h after DHT injection, were not different from those in adult male rats. On the contrary, microinjection of DHT into the bed nucleus of the stria terminalis, the hypothalamic periventricular nucleus, or the hypothalamic arcuate-ventromedial nucleus did not affect the secretory pattern of GH. The data indicate that DHT primarily acts on cells in the MPA through androgen receptors and modulates the secretion of somatostatin and/or GH-releasing hormone secondarily to masculinize the GH secretory pattern in OVX rats.


Assuntos
Di-Hidrotestosterona/farmacologia , Hormônio do Crescimento/metabolismo , Ovariectomia , Área Pré-Óptica/efeitos dos fármacos , Caracteres Sexuais , Animais , Di-Hidrotestosterona/administração & dosagem , Feminino , Cinética , Masculino , Microinjeções , Área Pré-Óptica/fisiologia , Ratos , Ratos Sprague-Dawley
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