RESUMEN
Bovine brain-derived acidic fibroblast growth factor (aFGF) is a protein mitogen originally identified in partially purified preparations of whole brain. The protein was purified to homogeneity and shown to be a potent vascular endothelial cell mitogen in culture and angiogenic substance in vivo. The homology of aFGF to human interleukin-1 beta was inferred from partial sequence data. The complete amino acid sequence of aFGF has now been determined and observed to be similar to both basic FGF and interleukin-1's. A neuropeptide-like sequence, flanked by basic dipeptides, was observed within the aFGF sequence.
Asunto(s)
Química Encefálica , Factores de Crecimiento de Fibroblastos/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Bovinos , Hormonas , Humanos , Concentración de Iones de Hidrógeno , Proteínas del Tejido Nervioso , Homología de Secuencia de Ácido Nucleico , Especificidad de la EspecieRESUMEN
Pure bovine brain-derived acidic fibroblast growth factor is a very potent mitogen for vascular endothelial cells in culture and, in the presence of heparin, induces blood vessel growth in vivo. Partial amino acid sequence determinations confirm that this mitogen is a unique protein having amino acid sequence homology with human interleukin 1.
Asunto(s)
Factores de Crecimiento de Fibroblastos/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Química Encefálica , Bovinos , Células Cultivadas , Embrión de Pollo/efectos de los fármacos , Endotelio/efectos de los fármacos , Interleucina-1/genética , Neovascularización Patológica , Homología de Secuencia de Ácido NucleicoRESUMEN
Bovine brain, hypothalamus, pituitary, and retina contain potent anionic polypeptide mitogens for endothelial cells. Immunological assays using murine monoclonal antibodies against bovine endothelial cell growth factor (ECGF) and radioreceptor assays using [125I]ECGF were performed to determine the cross-reactivity of ECGF with bovine acidic pI brain-derived fibroblast growth factor (acidic FGF) and bovine eye-derived growth factor-II [EDGF-II). We observed that acidic FGF and EDGF-II are recognized by anti-ECGF monoclonal antibodies and compete with [125I] ECGF for receptor occupancy. Furthermore, the biological activity of ECGF, acidic FGF, and EDGF-II is potentiated by the glycosaminoglycan, heparin. These results argue that ECGF, acidic FGF, and EDGF-II belong to a common family of polypeptide growth factors.
Asunto(s)
Química Encefálica , Factores de Crecimiento de Fibroblastos/metabolismo , Sustancias de Crecimiento/clasificación , Sustancias de Crecimiento/metabolismo , Animales , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Unión Competitiva , Bovinos , División Celular/efectos de los fármacos , Células Cultivadas , Reacciones Cruzadas , Sinergismo Farmacológico , Factores de Crecimiento Endotelial , Endotelio/efectos de los fármacos , Factor de Crecimiento Epidérmico/inmunología , Factor de Crecimiento Epidérmico/metabolismo , Factores de Crecimiento de Fibroblastos/inmunología , Sustancias de Crecimiento/inmunología , Heparina/inmunología , Heparina/metabolismo , Heparina/farmacología , Humanos , Proteínas , Receptores de Superficie Celular/metabolismoRESUMEN
Acidic brain fibroblast growth factor has been purified a minimum of 35,000-fold to apparent homogeneity by a combination of differential salt precipitation, ion exchange chromatography, gel filtration, isoelectric focusing, and hydrophobic chromatography on a C4 reversed-phase HPLC column. Two microheterogeneous forms of the molecule are obtained with apparent molecular masses of 16,600 and 16,800 daltons. The mitogen is highly active with half-maximal stimulation of BALB/c 3T3 fibroblasts at about 40 pg/ml in an assay using incorporation of [methyl-3H]thymidine into DNA.
Asunto(s)
Química Encefálica , Factores de Crecimiento de Fibroblastos/aislamiento & purificación , Aminoácidos/análisis , Animales , Bovinos , División Celular/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Factores de Crecimiento de Fibroblastos/farmacología , Punto Isoeléctrico , Peso MolecularRESUMEN
The effect of natural protease inhibitors and a chemoattractant on tumor cell invasion were studied with the use of a new in vitro quantitative assay of tumor cell penetration of native connective tissue. Human amnion membrane denuded of its epithelium is composed of a continuous basement membrane (BM) attached to a dense avascular collagenous stroma. M5076 reticulum sarcoma cells, known to be highly invasive in vivo, were placed on the BM side of the amnion connective tissue. Tumor cells penetrating the full thickness of the connective tissue barrier were collected on the stromal side with a Millipore filter. N-Formylmethionyl-leucyl-phenylalanine (FMLP) at an optimal concentration of 10(-7) M stimulated the penetration of up to 600% more tumor cells into the connective tissue after 20 hours in comparison to the number of tumor cells spontaneously penetrating in serum-free media. Natural protease inhibitors blocked both FMLP-stimulated and spontaneous invasion. A bovine cartilage extract containing inhibitors of both serine proteinases and metalloproteinases caused a 500% decrease in invasion. Furthermore, a 500% inhibition of invasion was produced by a purified collagenase (metalloproteinase) inhibitor. In contrast, soybean trypsin inhibitor and bovine serum albumin did not significantly alter the invasion rate. The protease inhibitors were nontoxic and did not reduce tumor cell proliferation, attachment to the amnion, and the rate of tumor cell migration through Nuclepore filters. These data support the hypothesis that collagenolytic metalloproteinases play a necessary role in tumor cell invasion of native connective tissue.
