RESUMEN
Cervical cancer is associated with human papilloma virus infection. However, this infection is insufficient to induce transformation and progression. Loss of heterozygosity analyses suggest the presence of a tumor suppressor gene (TSG) on chromosome 6p21.3-p25. Here we report the cloning NOL7, its mapping to chromosome band 6p23, and localization of the protein to the nucleolus. Fluorescence in situ hybridization analysis demonstrated an allelic loss of an NOL7 in cultured tumor cells and human tumor samples. Transfection of NOL7 into cervical carcinoma cells inhibited their growth in mouse xenografts, confirming its in vivo tumor suppressor activity. The induction of tumor dormancy correlated with an angiogenic switch caused by a decreased production of vascular endothelial growth factor and an increase in the production of the angiogenesis inhibitor thrombospondin-1. These data suggest that NOL7 may function as a TSG in part by modulating the expression of the angiogenic phenotype.
Asunto(s)
Nucléolo Celular/química , Genes Supresores de Tumor , Neovascularización Patológica/prevención & control , Neoplasias del Cuello Uterino/genética , Animales , Línea Celular Tumoral , Mapeo Cromosómico , Cromosomas Humanos Par 6 , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Trombospondina 1/genética , Neoplasias del Cuello Uterino/irrigación sanguínea , Factor A de Crecimiento Endotelial Vascular/genéticaRESUMEN
UpI is a basic protein, with molecular mass (approximately 28 kDa) and a pI > 9.4, isolated from the sea anemone Urticina piscivora. It is a potent cardiac stimulatory protein with the partial amino acid sequence D1ENEN5LYGPN10ENKAK15AKDLT20AGASY25LTKEA30GCTKL35QAGCT40MYQAY45N [1]. The toxic effects of UpI and the crude extract from which it was isolated have been investigated on three tumour cell lines: KB, L1210, and HEL 299 cells. UpI, however, was less potent on each cell line than the crude extract. Since previous experiments had shown extracts of U. piscivora to be haemolytic on erythrocytes of rat, guinea pig and dog, the haemolytic action of UpI was investigated. It was found to be a potent haemolysin on erythrocytes of rat, guinea pig, dog, pig and human, causing haemolysis on erythrocytes of each species tested at concentrations as low as 10(-10) M. Haemolysis was inhibited in a concentration-dependent manner by the phospholipid sphingomyelin but not cholesterol. Using scanning electron microscopy, it is now being shown that UpI produces significant structural damage to membranes of erythrocytes from rat and guinea pig. It proved to be a potent ichthyotoxin. These data suggest that sea anemone toxin not only possess different pharmacological activities but that UpI, one of the active constituents, could be responsible for the different pharmacological effects exhibited by the crude extract.
Asunto(s)
Venenos de Cnidarios/toxicidad , Toxinas Marinas/toxicidad , Secuencia de Aminoácidos , Animales , Supervivencia Celular/efectos de los fármacos , Colesterol/farmacología , Venenos de Cnidarios/química , Perros , Eritrocitos/efectos de los fármacos , Eritrocitos/ultraestructura , Peces , Cobayas , Hemólisis/efectos de los fármacos , Humanos , Técnicas In Vitro , Células KB , Leucemia L1210/tratamiento farmacológico , Toxinas Marinas/química , Ratones , Microscopía Electrónica de Rastreo , Datos de Secuencia Molecular , Ratas , Esfingomielinas/farmacología , Porcinos , Células Tumorales CultivadasRESUMEN
The antibacterial activities of the methanol and hot and cold aqueous extracts of the leaves of Aspilia africana, Ficus exasperata and Mareya micrantha were bioassayed against three Gram-negative and three Gram-positive bacterial species: Aerobacter aerogenes, Agrobacterium tumefaciens, Bacillus subtilis, Clostridium sporogenes, Escherichia coli and Staphylococcus aureus. The methanol and aqueous extracts of the leaves of Aspilia africana and Mareya micrantha and the undiluted oil of M. micrantha exhibited differential antibacterial activities on both Gram-positive and Gram-negative bacterial species at concentrations ranging from 0.1 to 0.5 g/ml. Extracts of Ficus exasperata leaves were inactive at all concentrations tested.