RESUMEN
Ectodomain shedding is an important mechanism to regulate the biological activities of membrane proteins. We focus here on the signaling mechanism of the ectodomain shedding of heparin-binding epidermal growth factor (EGF)-like growth factor (pro HB-EGF). Lysophosphatidic acid (LPA), a ligand for seven-transmembrane G protein-coupled receptors, stimulates the shedding of pro HB-EGF, which constitutes a G protein-coupled receptor-mediated transactivation of the EGF receptor. Experiments using a series of inhibitors and overexpression of mutant forms of signaling molecules revealed that the Ras-Raf-MEK signal is essential for the LPA-induced shedding. In addition, the small GTPase Rac is involved in the LPA-induced shedding, possibly to promote MEK activation. 12-O-Tetradecanoylphorbol-13-acetate is another potent inducer of pro HB-EGF shedding. We also demonstrate that the LPA-induced pathway is distinct from the 12-O-tetradecanoylphorbol-13-acetate-induced pathway and that these pathways constitute a dual signaling cascade that regulates the shedding of pro HB-EGF.
Asunto(s)
Factor de Crecimiento Epidérmico/química , Factor de Crecimiento Epidérmico/metabolismo , Lisofosfolípidos/farmacología , Receptores de Superficie Celular/química , Receptores de Superficie Celular/metabolismo , Transducción de Señal , Androstadienos/farmacología , Animales , Western Blotting , Membrana Celular/metabolismo , Células Cultivadas , Chlorocebus aethiops , Relación Dosis-Respuesta a Droga , Activación Enzimática , Inhibidores Enzimáticos/farmacología , GTP Fosfohidrolasas/metabolismo , Factor de Crecimiento Similar a EGF de Unión a Heparina , Péptidos y Proteínas de Señalización Intercelular , Ligandos , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Modelos Biológicos , Mutación , Plásmidos/metabolismo , Proteína Quinasa C/metabolismo , Estructura Terciaria de Proteína , Proteínas Proto-Oncogénicas c-raf/metabolismo , Acetato de Tetradecanoilforbol , Factores de Tiempo , Activación Transcripcional , Transfección , Células Vero , Wortmanina , Proteínas ras/metabolismoRESUMEN
Because CD9 is implicated in cell growth, cell adhesion and cell motility, altered CD9 expression might be involved in cancer invasion and metastasis. We have studied the immunolocalization of CD9 in oral squamous cell carcinoma (SCC). Sections prepared from paraffin-embedded specimens from patients with SCC of the oral cavity were stained with a monoclonal anti-CD9 antibody by means of the streptoavidin biotin method. Significant reduction or complete loss of CD9 expression was observed in cancer cells at the periphery of the cancer nests in the advancing front of invading tumor. Among 78 cases of oral SCCs examined, 46 (59.0%) cases were completely negative for CD9 expression. Loss of CD9 expression in cancer tissue strongly correlated with a high incidence of cervical lymph node metastasis and poorer prognosis (P=0.001). Thus a close examination of CD9 in SCC tissue would be useful for the prognosis of patients with oral carcinoma.
Asunto(s)
Antígenos CD/análisis , Carcinoma de Células Escamosas/inmunología , Metástasis Linfática/patología , Glicoproteínas de Membrana/análisis , Neoplasias de la Boca/inmunología , Anciano , Anticuerpos Monoclonales , Antígenos CD/genética , Western Blotting , Carcinoma de Células Escamosas/secundario , Adhesión Celular/inmunología , División Celular/inmunología , Movimiento Celular/inmunología , Colorantes , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Técnicas para Inmunoenzimas , Incidencia , Metástasis Linfática/inmunología , Masculino , Glicoproteínas de Membrana/genética , Persona de Mediana Edad , Neoplasias de la Boca/patología , Invasividad Neoplásica , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Prevalencia , Pronóstico , Tetraspanina 29RESUMEN
To examine whether cancer cell dissemination results from incisional biopsy, we tried to detect squamous cell carcinoma (SCC) cells in peripheral blood before and after incisional biopsy by means of cytokeratin 19 (CK19) reverse-transcriptase polymerase chain reaction (RT-PCR). The study population consisted of 20 patients with oral SCC; 10 were given incisional biopsies followed by radical excision (the incisional biopsy group), and the remaining 10 were treated by excisional biopsy alone (the excisional biopsy group). Ten non-oral cancer patients with benign oral lesions served as controls. Five-ml blood aspirates collected before and after incision were used for CK19 RT-PCR. Two (20.0%) of 10 patients from the incisional biopsy group were positive for CK19 transcripts in their peripheral blood drained 15 min after incision. In contrast, CK19 transcript was not detected either in the excisional biopsy group or in controls. Surgical invasiveness for oral cancer, including incisional biopsy, causes dissemination of cancer cells into circulation, resulting in increased risk of metastasis.
Asunto(s)
Biopsia/efectos adversos , Carcinoma de Células Escamosas/diagnóstico , Neoplasias de la Boca/diagnóstico , Siembra Neoplásica , Anciano , Anciano de 80 o más Años , Biopsia/métodos , Carcinoma de Células Escamosas/sangre , Estudios de Casos y Controles , ADN de Neoplasias/análisis , Femenino , Humanos , Queratinas/análisis , Masculino , Persona de Mediana Edad , Neoplasias de la Boca/sangre , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
CD9 is an integral membrane protein associated with integrins and other membrane proteins. Mice lacking CD9 were produced by homologous recombination. Both male and female CD9-/- mice were born healthy and grew normally. However, the litter size from CD9-/- females was less than 2% of that of the wild type. In vitro fertilization experiments indicated that the cause of this infertility was due to the failure of sperm-egg fusion. When sperm were injected into oocytes with assisted microfertilization techniques, however, the fertilized eggs developed to term. These results indicate that CD9 has a crucial role in sperm-egg fusion.
Asunto(s)
Antígenos CD/fisiología , Infertilidad Femenina/fisiopatología , Glicoproteínas de Membrana , Oocitos/fisiología , Interacciones Espermatozoide-Óvulo/fisiología , Animales , Membrana Celular/inmunología , Membrana Celular/metabolismo , Cruzamientos Genéticos , Desarrollo Embrionario y Fetal , Femenino , Fertilización/fisiología , Fertilización In Vitro , Marcación de Gen , Integrina alfa6beta1 , Integrinas/fisiología , Tamaño de la Camada , Masculino , Ratones , Ratones Endogámicos C57BL , Oocitos/inmunología , Ovulación , Tetraspanina 29RESUMEN
CD9 and CD63 belong to a tetramembrane-spanning glycoprotein family called tetraspanin, and are involved in a wide variety of cellular processes, but the structure-function relationship of this family of proteins has yet to be clarified. CD9 associates with diphtheria toxin receptor (DTR), which is identical to the membrane-anchored form of heparin-binding EGF-like growth factor (proHB-EGF). CD9 upregulates the diphtheria toxin (DT) binding activity of DTR/proHB-EGF, while CD63 does not upregulate the DT binding activity in spite of the fact that this protein also associates with DTR/proHB-EGF on the cell surface. CD9 molecules localize on the cell surface, while those of CD63 localize predominantly at lysosomes and intracellular compartments. We made CD9/CD63 chimeric molecules and then studied their intracellular localization and upregulation activities. The C-terminal regions of CD63, which includes the lysosome sorting motif, showed a strong inhibitory effect on the expression of the chimeric proteins at the cell surface, while mutants lacking the lysosome sorting motif delivered more efficiently on the cell surface, indicating that the lysosome sorting motif contributes to the inhibitory effect of the C-terminal region. However, the N-terminal half of this family of proteins containing the 1st to 3rd transmembrane domains also seems to influence the cell surface expression. For the upregulation of DT binding activity the large extracellular loop (EC2) of CD9 was essential, while the remaining regions influenced the upregulation activity by changing the efficiency of cell surface expression. From these results we discussed the structure-function relationship of this family of proteins.
Asunto(s)
Antígenos CD/metabolismo , Toxina Diftérica/metabolismo , Glicoproteínas de Membrana , Glicoproteínas de Membrana Plaquetaria/metabolismo , Proteínas Recombinantes de Fusión/genética , Fracciones Subcelulares/ultraestructura , Animales , Antígenos de Superficie , Técnicas In Vitro , Lisosomas/ultraestructura , Ratones , Unión Proteica/fisiología , Estructura Terciaria de Proteína/fisiología , Ratas , Proteínas Recombinantes de Fusión/metabolismo , Tetraspanina 29 , Tetraspanina 30 , Regulación hacia Arriba/fisiologíaRESUMEN
Efficacy and safety of sulbactam/cefoperazone (SBT/CPZ) was studied on gynecological infections. The results obtained are as follows: In the treatment of 31 cases of gynecological infections, the clinical efficacy of SBT/CPZ was assessed as excellent in 9 cases and effective in 22 cases. As for the bacteriological effects of SBT/CPZ, clinically isolated organisms were completely (100%) eradicated. In comparison with MICs of CPZ, SBT/CPZ was found to show a combined effect on Gram-negative and Gram-positive organisms in the order mentioned, but this effect was not observed against anaerobes. The combined effect of SBT/CPZ on beta-lactamase producing bacteria was also investigated in the same manner. As a result, SBT/CPZ was found to exert a combined effect on beta-lactamase strains of S. aureus, S. epidermidis, E. coli, B. catarrhalis and B. fragilis. The laboratory tests performed before and after administration of SBT/CPZ revealed rise in GOT and GPT values in 1 case, GPT values in 2 cases and eosinophil in 1 case. However, these rises were all mild and required no particular measures.
Asunto(s)
Infecciones Bacterianas/tratamiento farmacológico , Cefoperazona/administración & dosificación , Enfermedades de los Genitales Femeninos/tratamiento farmacológico , Ácido Penicilánico/administración & dosificación , Inhibidores de beta-Lactamasas , Adulto , Anciano , Bacterias/efectos de los fármacos , Bacterias/aislamiento & purificación , Infecciones Bacterianas/microbiología , Cefoperazona/farmacología , Combinación de Medicamentos , Evaluación de Medicamentos , Farmacorresistencia Microbiana , Femenino , Enfermedades de los Genitales Femeninos/microbiología , Humanos , Persona de Mediana Edad , Ácido Penicilánico/farmacología , SulbactamRESUMEN
Ceftazidime (CAZ) was studied for its transference into adnexa uteri and uterine tissues as well as for its effects and safety on gynecological infections. The results obtained are as follows: Peak levels of CAZ were obtained in the tissues of adnexa uteri and uteri at 15--30 minutes after one shot intravenous injection of CAZ 1 g, and relatively high concentrations were maintained for several hours. In the treatment of 33 cases of gynecological infections, the clinical efficacy of CAZ was assessed as excellent in 13 cases and effective in 20 cases. As for the bacteriological effects of CAZ, 95.5% of clinically isolated organisms were eradicated. The laboratory tests performed before and after administration of CAZ revealed rise in GOT, GPT values in 2 cases and eosinophilia in 1 case. However, these cases were all mild and required no particular measures.