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Query: KEGG:D02003 (NBT)
 1,323 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The comparative biological properties of NBT-II cells, a rat bladder carcinoma cell line constitutively expressing FGF-1 and FGF-2 were analysed in nude mice. FGF-1 is not secreted by the transfected cells unless the cDNA contains a signal sequence; conversely, NBT-II cells transfected with FGF-2 coding sequence produce and secrete the factor in a biologically active form. Bovine brain capillary endothelial cells are stimulated to proliferate upon addition of medium conditioned by the FGF-2-producing cells and this activity can be abrogated by the addition of anti-FGF-2 blocking antibodies. In addition, the FGF-2-containing medium, which cannot stimulate NBT-II cells due to absence of appropriate receptors, is able to induce scattering of NBT-II cells expressing the FGFR1. It has been reported previously that FGF-1-producing cells are highly tumorigenic in nude mice and induce carcinoma with a period of latency reduced from 6 to 5 weeks when compared to parental NBT-II cells. In contrast, NBT-II cells producing FGF-2 are no more tumorigenic than parental cells, indicating that FGF-1 and FGF-2 have different oncogenic properties in carcinoma. FGF-1 and FGF-2 are potent antiogenic factors that trigger the host endothelial cells. VEGF, another potent angiogen was found to be expressed in small amounts by NBT-II cells and to be expressed in reduced amount in the FGF-producing cells. In the NBT-II system in vivo FGF-1 and FGF-2 are highly and comparatively angiogenic in the resultant carcinoma and this occurs in the absence of production of significant amounts of VEGF by the carcinoma cells. Taken together, our results indicate that activated angiogenesis is not sufficient for rapid tumor expansion. FGF-1 behaves as a tumorigenic factor in the NBT-II bladder carcinoma cell model, whereas expression and secretion of large amounts of FGF-2 are not sufficient for increasing tumor growth.
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PMID:FGF-2 and FGF-1 expressed in rat bladder carcinoma cells have similar angiogenic potential but different tumorigenic properties in vivo. 903 74

The role of FGF-2 in tumor progression and tumor cell invasiveness was investigated using the rat bladder carcinoma cells NBT-II, which do not constitutively express FGF-2 or its membrane-spanning receptor. The NBT-II cells were transfected using expression vectors encoding either the 18 kD or the 24 kD isoform of FGF-2. The 24 kD isoform contains a nuclear localization signal. The transfected NBT-II cells that expressed 18 kD FGF-2 produced and secreted this factor as the biologically active form and retained an epithelial morphology. When injected to nude mice, the tumorigenic potential of these cells was not increased over that of non-transfected NBT-II cells; however, although the time to tumor development was long, the tumors were highly vascularized, indicating secretion of the angiogenic factor FGF-2. The transfected NBT-II cells that expressed 24 kD FGF-2 varied in their morphological appearance and did not secrete FGF-2; immunofluorescence and Western-blot studies showed that the FGF-2 was mainly intranuclear. When injected to nude mice, these cells produced tumors and migrated not only to the lymph nodes but also to the lungs where they produced metastases. In aggregate, these data indicate that stimulation of angiogenesis is not sufficient to increase tumor growth and that nuclear FGF-2 acts as a tumorigenic and metastasis-promoting factor in the NBT-II carcinoma model.
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PMID:[Impact on tumor angiogenesis and tumor progression of expression of the 18 kd and 24 kd isoforms of FGF-2]. 1037 8

FGF-1 and FGF-2 are pleiotropic growth factors for many cell types, operating through the activation of specific transmembrane FGF receptors (FGFRs). The role of these factors in tumor progression was investigated, with specific discrimination between their autocrine and non autocrine cellular activity. The rat bladder carcinoma NBT-II cells were engineered to produce FGF-1 or 18 kDa FGF-2 in the presence or absence of their specific receptor. Non-autocrine cells that produced FGF-1 or FGF-2 but lacked FGFRs were epithelial and reminiscent of the parental NBT-II cells. Whilst autocrine cells, which both constitutively produced and secreted the growth factor and expressed FGFRs, had a highly invasive mesenchymal phenotype. Correspondingly, the autocrine cells were highly tumorigenic in vivo compared to the parental and non-autocrine cells, which correlated with the increased production of uPAR and active uPA and increased in vitro invasive potential. Although all cells produced VEGF, only tumors derived from cells that produced FGF-1 or FGF-2 were highly vascularized, suggesting that these two growth factors could be involved in the angiogenic process by activating host endothelial cells. As a result of activation of the FGFR in autocrine cells, changes in cell morphology and an increase in the invasive and tumorigenic properties were observed, however no in vitro or in vivo differential functions between FGF-1 and FGF-2 could be identified in this system. In conclusion, our data demonstrates that rapid tumor development is not dependent upon increased tumor vascularization, suggesting that 'basal' angiogenesis, probably mediated by VEGF, is sufficient to support tumor growth.
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PMID:Rapid tumor development and potent vascularization are independent events in carcinoma producing FGF-1 or FGF-2. 1244 48

The hypothesis that tumor growth is angiogenesis-dependent has been documented by a considerable body of direct and indirect experimental data. Since the discovery of the vascular endothelial growth factor (VEGF), most attention has been focused on the VEGF system. Although fibroblast growth factors 1 and 2 (FGF-1 and FGF-2) can exert a strong angiogenic activity when they are supplied as a single pharmacological agent, their role in pathological angiogenesis in preclinical models remains controversial. To decipher the contribution of FGF receptors in various models of angiogenesis, we took advantage of the anti-idiotypic strategy to obtain circulating agonists specific for FGFR-1 and FGFR-2 (AIdF-1 and AIdF-2). They mimicked FGF-1 and FGF-2 for receptor binding, signal transduction, proliferation of endothelial cells and differentiation of the bladder carcinoma cell NBT-II which expresses FGFR-2b but not FGFR-1. The constitutive expression of FGFR-1 allowed binding of FGF-2 and AIdF-2 and inhibition of the proliferation of NBT-II cells. AIdF-1 and AIdF-2 induced angiogenesis in the corneal pocket assay. Although FGFR-1 dimerization achieved by AIdF-2 injection led to highly differentiated and smaller NBT-II tumors, no sign of reduction of tumor angiogenesis was observed, thus suggesting that endothelial cells are resistant to FGF.
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PMID:Direct FGF receptor 1 activation through an anti-idiotypic strategy mimicks the biological activity of FGF-2 and inhibits the progression of the bladder carcinoma derived from NBT-II cells. 1527 29