Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 432
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Helminthol ; 95: e72, 2021 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-34879884

RESUMEN

Since the exogenous compound tris(hydroxymethyl)aminomethane (Tris) showed a potent chemoattractant activity for Brugia pahangi infective third-stage larvae (L3), it was assumed that, in natural infection to a host, filarial L3 can be expected to recognize an endogenous Tris-related compound. In addition, a few amino acids have been identified as water-soluble attractants for second-stage juveniles of Meloidogyne incognita, a plant parasitic nematode. Therefore, the present study assesses the in vitro chemotactic responses of B. pahangi L3 to Tris-related compounds and amino acids using an agar-plate assay. Among Tris-related compounds, 2-amino-1,3-propanediol (APD) and 2-amino-2-methyl-1,3-propanediol (AMPD) exhibited a potent chemoattractant activity for filarial L3 at a level similar to Tris. Furthermore, arginine (Arg) was identified as a potent attractant for filarial L3 among amino acids. In addition, filarial L3 were attracted to Arg, APD and AMPD in mild alkaline conditions rather than acidic conditions. The chemoattractant activity of the three compounds for filarial L3 was observed in concentrations between 6.3 and 200 mm. This is the first report to demonstrate that Arg, APD and AMPD are potent chemoattractants for B. pahangi L3. Endogenous Arg and APD, in particular, may be involved in the regulation of the chemotactic behaviour of filarial L3 in the infection to a host. The present results will help to elucidate the mechanism of filarial skin-penetrating invasion of a host.


Asunto(s)
Brugia pahangi , Filarioidea , Aminoácidos , Animales , Larva , Trometamina
2.
J Clin Pharm Ther ; 43(1): 117-120, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28718220

RESUMEN

WHAT IS KNOWN AND OBJECTIVE: Long-acting formulations are an important therapeutic option for non-adherent patients with schizophrenia. There is a commonly held view that management of long-acting formulation-induced side effects is difficult. CASE DESCRIPTION: We present a patient with schizophrenia who developed acute and persistent extrapyramidal symptoms requiring tracheostomy and long-term rehabilitation after long-acting injections of fluphenazine decanoate. Extrapyramidal symptoms improved with declining fluphenazine concentration and antiparkinsonian drug therapy with bromocriptine. WHAT IS NEW AND CONCLUSION: Long-acting formulations may lead to severe persistent adverse effects. For preventing fluphenazine-induced side effects, a possible option might be the antiparkinsonian drug therapy with bromocriptine.


Asunto(s)
Enfermedades de los Ganglios Basales/inducido químicamente , Flufenazina/efectos adversos , Femenino , Flufenazina/uso terapéutico , Humanos , Persona de Mediana Edad , Cooperación del Paciente , Esquizofrenia/tratamiento farmacológico
3.
J Helminthol ; 92(3): 317-321, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-28735573

RESUMEN

Urocanic acid (UCA) is known as a major chemoattractant for Strongyloides stercoralis infective third-stage larvae (L3). Since Brugia pahangi is a skin-penetrating parasitic nematode similar to S. stercoralis, UCA was expected to be a chemoattractant for B. pahangi L3. Thus, the chemoattractant activity of UCA for B. pahangi L3 was assessed. The chemotactic responses of B. pahangi L3 to UCA or acetic acid (CH3COOH) dissolved in amine solutions were assessed using an agar-plate assay. A test solution of 200 mm UCA dissolved in aqueous 270 mm tris(hydroxymethyl)aminomethane (Tris) significantly attracted B. pahangi L3 compared with deionized water (DW), while neither a solution of 200 mm UCA dissolved in aqueous 230 mm ammonia (NH3) nor 290 mm triethylamine (TEA) significantly attracted L3. Similarly, a test solution of 200 mm CH3COOH dissolved with 200 mm Tris significantly attracted L3, but neither a test solution of 200 mm CH3COOH plus 200 mm NH3 nor 200 mm TEA attracted L3. Furthermore, L3 were significantly attracted to 200 mm Tris alone, compared with DW, but avoided 200 mm NH3 and 200 mm TEA. Moreover, the chemoattractant activity of Tris for L3 was observed even at a low concentration of 25 mm, and it was observed in a mild alkaline condition but not in an acidic condition. The present study reveals that Tris is a potential chemoattractant for B. pahangi L3 while UCA is not. This finding will contribute to an understanding of the mechanisms of skin-penetrating infection of filarial L3.


Asunto(s)
Brugia pahangi/efectos de los fármacos , Factores Quimiotácticos/farmacología , Quimiotaxis/efectos de los fármacos , Larva/efectos de los fármacos , Ácido Acético/farmacología , Animales , Concentración de Iones de Hidrógeno , Trometamina/química , Ácido Urocánico/farmacología
4.
Br J Cancer ; 112(2): 403-12, 2015 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-25314065

RESUMEN

BACKGROUND: Sessile serrated adenomas/polyps (SSA/Ps) are a putative precursor of colon cancer with microsatellite instability (MSI). However, the developmental mechanism of SSA/P remains unknown. We performed genetic analysis and genome-wide DNA methylation analysis in aberrant crypt foci (ACF), SSA/P, and cancer in SSA/P specimens to show a close association between ACF and the SSA/P-cancer sequence. We also evaluated the prevalence and number of ACF in SSA/P patients. METHODS: ACF in the right-side colon were observed in 36 patients with SSA/Ps alone, 2 with cancers in SSA/P, and 20 normal subjects and biopsied under magnifying endoscopy. B-RAF mutation and MSI were analysed by PCR-restriction fragment length polymorphism (RFLP) and PCR-SSCP, respectively, in 15 ACF, 20 SSA/P, and 2 cancer specimens. DNA methylation array analysis of seven ACF, seven SSA/P, and two cancer in SSA/P specimens was performed using the microarray-based integrated analysis of methylation by isochizomers (MIAMI) method. RESULTS: B-RAF mutations were frequently detected in ACF, SSA/P, and cancer in SSA/P tissues. The number of methylated genes increased significantly in the order of ACF

Asunto(s)
Focos de Criptas Aberrantes/genética , Adenoma/genética , Neoplasias del Colon/genética , Proteínas Proto-Oncogénicas B-raf/genética , Anciano , Estudios de Casos y Controles , Metilación de ADN , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Mutación Missense
5.
J Helminthol ; 86(4): 406-9, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22030560

RESUMEN

In vitro chemotactic responses of infective third-stage larvae (L3) of Brugia pahangi to NaCl, Na2HPO4, KCl, K2HPO4, MgCl2 and CaCl2 were assessed. Compared to deionized water as a control, 200 mm NaCl and 100 mm Na2HPO4 significantly attracted L3 (P < 0.01 and P < 0.01), whereas L3 were likely to avoid 200 mm KCl and 100 mm K2HPO4 (P < 0.05 and P < 0.05). L3 showed no significant tendency to avoid or to be attracted to 200 mm CaCl2 and 200 mm MgCl2. Furthermore, NaCl exhibited a significant chemoattractant activity for L3 at a low concentration of 100 mm.


Asunto(s)
Brugia pahangi/fisiología , Factores Quimiotácticos/metabolismo , Quimiotaxis , Iones/metabolismo , Sodio/metabolismo , Animales , Brugia pahangi/efectos de los fármacos , Larva/efectos de los fármacos , Larva/fisiología
6.
J Cell Biol ; 104(4): 1105-15, 1987 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-3104350

RESUMEN

To establish the relation of glycosaminoglycan synthesis to cell proliferation, we investigated the synthesis of individual glycosaminoglycan species by intact cells and in a cell-free system, using normal and transformed human fibroblasts under differing culture conditions. Reducing serum concentration brought about a marked decline in the synthesis of hyaluronate (HA) as well as cell proliferation on both normal and transformed cells. Both HA synthesis and proliferation decreased with increasing cell densities markedly (in inverse proportion to cell density) in normal cells but gradually in transformed cells. This noticeable congruity of the changes in HA synthesis and proliferation indicates that the change in HA synthesis is related primarily to cell proliferation rather than to cell density or cellular transformation. Examination of HA synthesis in a cell-free system demonstrated that the activity of HA synthetase also fluctuated in conjunction with cell proliferation. Furthermore, growth-reduced cells (except crowded transformed cells) inhibited cell-free HA synthesis and this inhibition was induced coincidentally with a decrease in both HA synthetase activity and proliferation. These findings suggest that the change in HA synthesis is significant in the regulation of cell proliferation.


Asunto(s)
Fibroblastos/citología , Glucuronosiltransferasa/antagonistas & inhibidores , Glicosiltransferasas , Proteínas de la Membrana , Transferasas , Proteínas de Xenopus , División Celular , Línea Celular , Medios de Cultivo , Glicosaminoglicanos/biosíntesis , Humanos , Hialuronano Sintasas , Cinética
7.
J Helminthol ; 83(1): 7-11, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18845029

RESUMEN

The effect of artesunate (ART) on the survival time of adult worm pairs of Schistosoma mansoni and on their egg output during in vitro culture was assessed. ART significantly decreased the survival time of both paired male and female worms at concentrations of 5, 10, 20 and 40 mg l- 1 during in vitro cultivation. An inhibitory effect of ART on the daily egg output of paired female worms during in vitro cultivation was also observed.


Asunto(s)
Artemisininas/farmacología , Oviposición/efectos de los fármacos , Recuento de Huevos de Parásitos/estadística & datos numéricos , Schistosoma mansoni/efectos de los fármacos , Esquistosomicidas/farmacología , Animales , Artesunato , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Técnicas In Vitro , Masculino , Distribución Aleatoria , Esquistosomiasis/tratamiento farmacológico , Factores Sexuales , Factores de Tiempo
8.
Transplant Proc ; 40(7): 2400-2, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18790247

RESUMEN

A cohort of 429 patients who received kidney grafts between 1973 and 2007 at our hospital was studied for the incidence and sites of malignancy. Sixty-two malignant diseases developed in 57 of 429 patients (13.3%). The cumulative incidences of malignancy increased markedly in the second and third posttransplantation decades. The overall rates were 1.8% at 5 years, 6.7% at 10 years, 12.5% at 15 years, 17.3% at 20 years, and 25.6% at 25 years. In the second and third posttransplantation decades, patients without malignancy showed significantly superior survival versus than those with cancer (P = .0002). Their survival rates were 83.4% versus 86.9% at 10 years and 63.1% versus 80.3% at 20 years, respectively. Skin cancer, renal cell carcinoma of the native kidney, hepatocellular carcinoma, posttransplantation lymphoproliferative disease, uterine cancer, and colorectal cancer were common in our series. The 5-year survival rates after the treatment of malignancy were better for skin cancer and renal cell carcinoma of the native kidney. Concerning the effects of immunosuppression, the tacrolimus-based group displayed a higher incidence among 3 groups (P = .0044).


Asunto(s)
Trasplante de Riñón/efectos adversos , Neoplasias/epidemiología , Cadáver , Femenino , Humanos , Incidencia , Japón , Trasplante de Riñón/mortalidad , Donadores Vivos/estadística & datos numéricos , Masculino , Neoplasias/mortalidad , Estudios Retrospectivos , Análisis de Supervivencia , Donantes de Tejidos/estadística & datos numéricos
10.
Transplant Proc ; 50(3): 895-897, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29571743

RESUMEN

BACKGROUND: Mycophenolate mofetil (MMF) and mizoribine (MZR) are increasingly used as immunosuppressive agents for organ transplantation and chronic inflammation. We report a patient with rheumatoid arthritis who had an acute inflammatory syndrome triggered by preoperative immunosuppression therapy with both MMF and MZR. CASE REPORT: A 41-year-old woman with IgA nephropathy was referred to our department for living donor renal transplantation. She had rheumatoid arthritis that was adequately treated with prednisolone 5 mg once a day and salazosulfapyridine 2000 mg once a day. MMF 1000 mg twice a day was started for desensitization therapy. Three days later, the patient developed arthritis in the joints of her left hand and elevated inflammatory markers. On day 7, MMF was switched to MZR 150 mg 3 times a day. However, the symptoms extended to both shoulders and the joints of the right foot; MZR was discontinued. The arthritis and inflammatory markers improved. Two months later, the patient was rechallenged with MMF followed by MZR, resulting in a similar clinical course as previously. Tacrolimus (TAC) 3 mg twice a day and everolimus (EVL) 0.5 mg twice a day were introduced as alternative immunosuppressant therapies. No arthritis occurred. ABO-compatible living donor renal transplantation was successfully performed. The patient received TAC, EVL, prednisolone, rituximab, and basiliximab, and her postoperative course was uneventful without arthritis or rejection. At 9 months postoperatively, the serum creatinine was 0.79 mg/dL. CONCLUSIONS: Acute inflammatory syndrome is an extremely rare complication triggered by preoperative immunosuppression therapy. If antimetabolites cannot be used in immunologically high-risk patients, transplantation becomes very difficult. Clinicians should keep in mind this paradoxical reaction.


Asunto(s)
Artritis/inducido químicamente , Inmunosupresores/efectos adversos , Trasplante de Riñón/métodos , Ácido Micofenólico/efectos adversos , Ribonucleósidos/efectos adversos , Adulto , Femenino , Rechazo de Injerto/prevención & control , Humanos , Inflamación/inducido químicamente , Síndrome
11.
Acta Trop ; 102(3): 165-71, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17572368

RESUMEN

The objective of this research was to assess drug efficacy in school children after mass chemotherapy with praziquantel and albendazole conducted in Mwea Division, Kirinyaga District, Central Kenya in 2004. In total 2300 children aged between 4 and 18 years in five primary schools were selected for the study. Before mass chemotherapy, prevalence of infection was 47.4% for Schistosoma mansoni, 16.7% for Necator americanus, 1.6% for Ascaris lumbricoides, and 0.8% for Trichuris trichiura. Post-treatment stool examination was carried out 8 weeks later, and a total of 1942 stool samples were collected. Prevalence decreased to 8.6% for S. mansoni, 0.2% for N. americunus, 0 for A. lumbricoides, and 0.6% for T. trichiura. Efficacy was good for S. mansoni and N. americanus (92.6% and 95.0%, respectively). Results of the first round of treatment of school-age children in Mwea indicate a good reduction in parasite burden.


Asunto(s)
Albendazol/uso terapéutico , Antihelmínticos/uso terapéutico , Helmintiasis/tratamiento farmacológico , Praziquantel/uso terapéutico , Adolescente , Envejecimiento , Niño , Preescolar , Helmintiasis/epidemiología , Humanos , Kenia/epidemiología , Prevalencia
12.
Oncogene ; 36(19): 2667-2679, 2017 05 11.
Artículo en Inglés | MEDLINE | ID: mdl-27893706

RESUMEN

A major genomic alteration in prostate cancer (PCa) is frequent loss of chromosome (chr) 8p with a common region of loss of heterozygosity (LOH) at chr8p22 locus. Genomic studies implicate this locus in the initiation of clinically significant PCa and with progression to metastatic disease. However, the genes within this region have not been fully characterized to date. Here we demonstrate for the first time that a microRNA component of this region-miR-383-is frequently downregulated in prostate cancer, has a critical role in determining tumor-initiating potential and is involved in prostate cancer metastasis via direct regulation of CD44, a ubiquitous marker of PCa tumor-initiating cells (TICs)/stem cells. Expression analyses of miR-383 in PCa clinical tissues established that low miR-383 expression is associated with poor prognosis. Functional data suggest that miR-383 regulates PCa tumor-initiating/stem-like cells via CD44 regulation. Ectopic expression of miR-383 inhibited tumor-initiating capacity of CD44+ PCa cells. Also, 'anti-metastatic' effects of ectopic miR-383 expression were observed in a PCa experimental metastasis model. In view of our results, we propose that frequent loss of miR-383 at chr8p22 region leads to tumor initiation and prostate cancer metastasis. Thus, we have identified a novel finding that associates a long observed genomic alteration to PCa stemness and metastasis. Our data suggest that restoration of miR-383 expression may be an effective therapeutic modality against PCa. Importantly, we identified miR-383 as a novel PCa tissue diagnostic biomarker with a potential that outperforms that of serum PSA.


Asunto(s)
Biomarcadores de Tumor/genética , Receptores de Hialuranos/genética , MicroARNs/genética , Neoplasias de la Próstata/genética , Anciano , Proliferación Celular/genética , Deleción Cromosómica , Cromosomas Humanos Par 8/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Neoplasias de la Próstata/patología , Análisis de Supervivencia
13.
Structure ; 4(1): 33-45, 1996 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-8805511

RESUMEN

BACKGROUND: Mouse lung carbonyl reductase (MLCR) is a member of the short-chain dehydrogenase/reductase (SDR) family. Although it uses both NADPH and NADH as coenzymes, the structural basis of its strong preference for NADPH is unknown. RESULTS: The crystal structure of the ternary complex of MLCR (with NADPH and 2-propanol) has been determined at 1.8 A resolution. This is the first three-dimensional structure of a carbonyl reductase, and MLCR is the first member of the SDR family to be solved in complex with NADPH (rather than NADH). Comparison of the MLCR ternary complex with three structures reported previously for enzymes of the SDR family (all crystallized as complexes with NADH) reveals a pair of basic residues (Lys17 and Arg39) making strong electrostatic interactions with the 2'-phosphate group of NADPH. This pair of residues is well conserved among the NADPH-preferring enzymes of the SDR family, but not among the NADH-preferring enzymes. In the latter, an aspartate side chain occupies the position of the two basic side chains. The aspartate residue, which would come into unacceptably close contact with the 2'-phosphate group of the adenosine moiety of NADPH, is replaced by a threonine or alanine in the primary sequences of NADPH-preferring enzymes of the SDR family. CONCLUSIONS: The cofactor preferences exhibited by the enzymes of the SDR family are mainly determined by the electrostatic environment surrounding the 2'-hydroxyl (or phosphate) group of the adenosine ribose moiety of NADH (or NADPH). Thus, positively charged and negatively charged environments correlate with preference for NADPH and NADH respectively.


Asunto(s)
Oxidorreductasas de Alcohol/química , 1-Propanol/química , Secuencia de Aminoácidos , Animales , Sitios de Unión , Coenzimas/metabolismo , Pulmón/metabolismo , Ratones , Modelos Moleculares , Datos de Secuencia Molecular , NAD/metabolismo , NADP/química , NADP/metabolismo , Oxidorreductasas/química , Unión Proteica , Conformación Proteica , Estructura Terciaria de Proteína , Especificidad por Sustrato
14.
Structure ; 7(8): 953-65, 1999 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-10467151

RESUMEN

BACKGROUND: Sphingomonas paucimobilis SYK-6 utilizes an extradiol-type catecholic dioxygenase, the LigAB enzyme (a protocatechuate 4,5-dioxygenase), to oxidize protocatechuate (or 3,4-dihydroxybenzoic acid, PCA). The enzyme belongs to the family of class III extradiol-type catecholic dioxygenases catalyzing the ring-opening reaction of protocatechuate and related compounds. The primary structure of LigAB suggests that the enzyme has no evolutionary relationship with the family of class II extradiol-type catecholic dioxygenases. Both the class II and class III enzymes utilize a non-heme ferrous center for adding dioxygen to the substrate. By elucidating the structure of LigAB, we aimed to provide a structural basis for discussing the function of class III enzymes. RESULTS: The crystal structure of substrate-free LigAB was solved at 2.2 A resolution. The molecule is an alpha2beta2 tetramer. The active site contains a non-heme iron coordinated by His12, His61, Glu242, and a water molecule located in a deep cleft of the beta subunit, which is covered by the alpha subunit. Because of the apparent oxidation of the Fe ion into the nonphysiological Fe(III) state, we could also solve the structure of LigAB complexed with a substrate, PCA. The iron coordination sphere in this complex is a distorted tetragonal bipyramid with one ligand missing, which is presumed to be the O2-binding site. CONCLUSIONS: The structure of LigAB is completely different from those of the class II extradiol-type dioxygenases exemplified by the BphC enzyme, a 2,3-dihydroxybiphenyl 1,2-dioxygenase from a Pseudomonas species. Thus, as already implicated by the primary structures, no evolutionary relationship exists between the class II and III enzymes. However, the two classes of enzymes share many geometrical characteristics with respect to the nature of the iron coordination sphere and the position of a putative catalytic base, strongly suggesting a common catalytic mechanism.


Asunto(s)
Dioxigenasas , Oxigenasas/química , Secuencia de Aminoácidos , Catálisis , Cristalografía por Rayos X , Hierro/química , Modelos Moleculares , Datos de Secuencia Molecular , Oxigenasas/metabolismo , Conformación Proteica , Pseudomonas/enzimología , Homología de Secuencia de Aminoácido
15.
J Int Med Res ; 34(6): 624-31, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17294994

RESUMEN

The aim of this study was to examine interleukin-6 production and the activation of signal transducer and activator of transcription-3 (STAT3) in ruptured rotator cuff tendon. Specimens of ruptured rotator cuff tendons were analysed using real-time reverse transcriptase polymerase chain reaction, Western blotting and immunohistochemistry. Specimens of co-existing inflammatory subacromial synovia were examined for comparison. The level of interleukin-6 messenger RNA was increased in ruptured rotator cuff tendon as well as in subacromial synovium. Western blot analysis showed constitutive production of activated, phosphorylated STAT3 in ruptured rotator cuff tendon and co-existing subacromial synovium. Immunohistochemical examination detected cells producing interleukin-6, interleukin-6 receptor and phosphorylated STAT3 in ruptured rotator cuff tendon, mainly in proliferative vessels and, to a lesser extent, in tendon fibroblasts around the vessels. This study demonstrates that activation of STAT3 induced by interleukin-6 is promoted mainly by proliferative vessels in ruptured rotator cuff tendon.


Asunto(s)
Interleucina-6/fisiología , Manguito de los Rotadores/patología , Rotura/metabolismo , Factor de Transcripción STAT3/metabolismo , Adulto , Secuencia de Bases , Cartilla de ADN , Humanos , Inmunohistoquímica , Interleucina-6/genética , Fosforilación , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
16.
Oncogene ; 13(6): 1231-7, 1996 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-8808697

RESUMEN

An 81 kDa protein was found to be highly expressed in spontaneously immortalized CD1-ICR mouse fibroblasts, RS-4, as compared to normal fibroblasts. RS-4 cells have a reduced serum requirement and exhibit multilayered growth in vitro but are not tumorigenic. The protein was purified from RS-4 cell extracts and used to obtain a polyclonal antibody that specifically immunoprecipitated an 81 kDa protein from cell lysates. Immunocloning of its cDNA and sequence analysis revealed its identity with ezrin, an F-actin binding protein that is a component of the cortical cytoskeleton. Microinjection of the purified IgG fraction of the anti-p81 antiserum into the cytoplasm of RS-4 cells blocked their entry into S phase suggesting that the protein has a proliferative function. Immunostaining of normal mouse tissues showed that the expression of p81/ezrin was highest in proliferating cell populations. Unlike RS-4, NIH3T3 cells exhibit contact inhibition and express levels of p81/ezrin similar to those of normal fibroblasts. When NIH3T3 cells were transfected with p81/ezrin cDNA they lost contact inhibition and thus resembled RS-4 cells. The study demonstrates a proliferative function of p81/ezrin and suggests its involvement in pathways that negatively regulate contact inhibition.


Asunto(s)
Fibroblastos/fisiología , Fosfoproteínas/fisiología , Células 3T3/citología , Animales , Comunicación Celular/fisiología , División Celular/fisiología , Células Cultivadas , Proteínas del Citoesqueleto , ADN Complementario/genética , Fibroblastos/citología , Fibroblastos/metabolismo , Ratones , Ratones Endogámicos ICR , Microinyecciones , Fosfoproteínas/biosíntesis , Fosfoproteínas/genética , Plásmidos , Transfección
17.
Oncogene ; 18(3): 593-605, 1999 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-9989809

RESUMEN

The cell cycle-regulated transcription factor E2F is a family of heterodimers composed of E2F and DP protein subunits. While DP proteins stabilize DNA binding of E2F proteins, and influence the entry of E2F-4 and E2F-5 into the nucleus, the role of DP proteins in E2F-dependent gene expression is not well understood. Using immunolocalization, immunoprecipitation, and cell fractionation experiments, here we show association with E2F subunits governs intracellular trafficking and ubiquitination of DP-1. In transient transfection experiments, DP-1 polypeptides that stably bound E2F-1 entered the nucleus. DP-1 proteins that failed to associate with E2F subunits accumulated in the cell cytoplasm as polyubiquitinated DP-1. A Chinese hamster cell line that conditionally expresses HA-DP-1 was used to examine the effect of DP-1 on cell cycle progression. In serum response experiments, moderate increases in HA-DP-1 led to a threefold increase in E2F DNA binding activity in vitro, a corresponding increase in dhfr gene expression during transition of G1, and higher rates of S phase entry. However, flow cytometry showed cells expressing very high levels of HA-DP-1 failed to enter the S phase. Inhibition of cell cycle progression by high levels of HA-DP-1 was associated with the accumulation of other ubiquitinated cellular proteins, including c-jun and the cyclin-dependent kinase inhibitor p21, indicating that degradation of ubiquitinated proteins is required for progression from G0 to S phase even in the presence of activated E2F. Under similar conditions, expression of E2F-1 reduced the levels of ubiquitinated cellular proteins and accelerated cell cycle progression. Our studies indicate association with E2F subunits prevents ubiquitin-dependent degradation of DP-1 in the cytoplasm by promoting nuclear entry of E2F/DP heterodimers.


Asunto(s)
Proteínas Portadoras , Proteínas de Ciclo Celular , Proteínas de Unión al ADN , Factores de Transcripción/metabolismo , Ubiquitinas/metabolismo , Animales , Transporte Biológico , Células CHO , Ciclo Celular , Cricetinae , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/metabolismo , ADN/metabolismo , Factores de Transcripción E2F , Factor de Transcripción E2F1 , Factor de Transcripción E2F4 , Factor de Transcripción E2F5 , Expresión Génica , Humanos , Líquido Intracelular , Proteínas Proto-Oncogénicas c-jun/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteína 1 de Unión a Retinoblastoma , Fase S , Factor de Transcripción DP1 , Factores de Transcripción/genética
18.
Oncogene ; 17(7): 907-11, 1998 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-9780007

RESUMEN

The murine mortalin genes, mot-1 and mot-2, are members of the hsp70 family of proteins and differ from each other by only two amino acid residues. Mot-1 is expressed in normal cells and has pancytosolic cellular distribution whereas mot-2 is found in the perinuclear region of immortal cells. We report here that a high level of expression of mot-2 protein resulted in malignant transformation of cells as analysed by anchorage independent growth and nude mice assays. A high level of protein expression is attributed to the 900 bp 3' untranslated region of the cDNA which does not have any transforming activity per se. Mortalin cDNA clones isolated from human transformed cells were also found to have transforming activity in similar assays and a high level of expression was apparent in some of the human immortalized cells that showed non-pancytosolic mortalin immunofluorescence. Taken together, the data suggest that nonpancytosolic mortalin may have a role in tumorigenesis.


Asunto(s)
Transformación Celular Neoplásica , Genes p53 , Proteínas HSP70 de Choque Térmico/biosíntesis , Proteínas HSP70 de Choque Térmico/genética , Células 3T3 , Animales , Secuencia de Bases , Proteínas Portadoras , Adhesión Celular , División Celular , Línea Celular Transformada , Clonación Molecular , ADN Complementario , Proteínas HSP70 de Choque Térmico/metabolismo , Humanos , Ratones , Ratones Desnudos , Proteínas Mitocondriales , Datos de Secuencia Molecular , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/metabolismo , Transfección
19.
Oncogene ; 3(4): 383-9, 1988 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-2978866

RESUMEN

A protein encoded by an hst-1 transforming gene was expressed in silkworm-derived BmN cells and secreted into the culture medium using a recombinant baculovirus vector. The strong affinity for heparin of the secreted protein made it possible to purify the hst-1 protein to homogeneity in a two-step procedure. The purified hst-1 protein has a molecular weight of 18,000 and stimulates both DNA synthesis in NIH3T3 cells and human umbilical vein endothelial cell proliferation. In addition, morphological changes and anchorage-independent growth of NIH3T3 cells are induced by this product. These results show that the hst-1 transforming protein is a novel heparin-binding growth factor as predicted by nucleotide sequence analysis.


Asunto(s)
Factores de Crecimiento de Fibroblastos , Sustancias de Crecimiento/genética , Heparina/genética , Proteínas Oncogénicas/genética , Oncogenes , Proteínas Proto-Oncogénicas , Animales , Secuencia de Bases , Bombyx , Adhesión Celular , División Celular/efectos de los fármacos , Línea Celular , Células Cultivadas , Cromatografía de Afinidad , Replicación del ADN/efectos de los fármacos , Endotelio Vascular/citología , Endotelio Vascular/efectos de los fármacos , Factor 4 de Crecimiento de Fibroblastos , Expresión Génica , Vectores Genéticos , Sustancias de Crecimiento/aislamiento & purificación , Sustancias de Crecimiento/farmacología , Mitógenos/genética , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Proteínas Oncogénicas/aislamiento & purificación , Proteínas Oncogénicas/farmacología , Transfección
20.
Oncogene ; 15(7): 759-69, 1997 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-9266962

RESUMEN

The transcription factors p53 and E2F-1 play important roles in the control of cell cycle progression. In transient transfection experiments, expression of E2F-1, other E2F family members, or p53 squelched transcription from cotransfected plasmids in a dose-dependent manner. Although the proteasome inhibitors MG-132 and lactacystin markedly increased the level of expression of E2F-1 and p53, these inhibitors completely alleviated squelching by both proteins. Several observations indicate MG-132 alleviates squelching by influencing the conformation of newly synthesized p53 and E2F-1:MG-132 increased the fraction of wild type p53 bound by a monoclonal antibody which preferentially recognizes mutant conformers of p53, increased binding of hsp70 to p53 and inhibited nuclear accumulation of both p53 and E2F-1, but not the pocket protein p107. The protease inhibitors ALLN and ALLM did not influence expression of E2F-1 or p53, nor did they alleviate squelching by either transcription factor. Because MG-132 and lactacycstin are highly specific inhibitors of the proteasome protease, our results suggest that the proteasome influences post-translational processes involved in proper folding and cytoplasmic clearing of E2F-1 and p53.


Asunto(s)
Acetilcisteína/análogos & derivados , Proteínas Portadoras , Proteínas de Ciclo Celular/metabolismo , Inhibidores de Cisteína Proteinasa/metabolismo , Proteínas de Unión al ADN , Leupeptinas/metabolismo , Factores de Transcripción/metabolismo , Transcripción Genética/efectos de los fármacos , Proteína p53 Supresora de Tumor/metabolismo , Acetilcisteína/metabolismo , Animales , Northern Blotting , Células CHO , Proteínas de Ciclo Celular/efectos de los fármacos , Proteínas de Ciclo Celular/genética , Cricetinae , Cicloheximida/farmacología , Inhibidores de Cisteína Proteinasa/farmacología , Factores de Transcripción E2F , Factor de Transcripción E2F1 , Leupeptinas/farmacología , Oligopéptidos/farmacología , Inhibidores de la Síntesis de la Proteína/farmacología , ARN Mensajero/metabolismo , Proteína 1 de Unión a Retinoblastoma , Factores de Transcripción/efectos de los fármacos , Factores de Transcripción/genética , Activación Transcripcional , Transfección , Proteína p53 Supresora de Tumor/efectos de los fármacos , Proteína p53 Supresora de Tumor/genética , Ubiquitinas/metabolismo , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA