The evaluation of basic fibroblast growth factor and fibroblastic growth factor receptor 1 levels in saliva and serum of patients with salivary gland tumor

Basic fibroblast growth factor (FGF2) is a well-known endothelial mitogen that regulates endothelial cell proliferation, migration, differentiation, and survival. In the present study, we investigated the levels of FGF2 and fibroblastic growth factor receptor 1 (FGFR1) in saliva and serum of patients with salivary gland tumors. Saliva and serum samples were collected from 43 patients with salivary gland tumors and 40 healthy volunteers. The FGF2 and FGFR1 concentrations in saliva and serum samples were measured by enzyme-linked immunosorbent assay. We found that the levels of FGF2 and FGFR1 in saliva and serum from patients with salivary gland tumors were significantly higher than those from healthy control subjects. These results suggest that salivary FGF2 and FGFR1 can be used as potential biomarkers in the diagnosis of salivary gland tumors.     

Expression of basic fibroblast growth factor in human gastric carcinomas

The expression of mRNA for the basic fibroblast growth factor (FGF) gene was examined in seven human gastric carcinoma cell lines and in tissue from 29 gastric carcinomas together with the adjacent normal mucosa. Among the seven gastric carcinoma cell lines, the MKN45 cell line expressed mRNA for the basic FGF gene. Basic FGF protein production was confirmed by flow cytometric analysis and immunohistochemistry. Among the surgical specimens, 16 (55%) of 29 gastric carcinomas showed higher levels of basic FGF mRNA than the normal mucosa. Interestingly, in scirr-hous gastric carcinomas characterized by their fibrous stroma and rapid growth, 9 (69%) of 13, samples examined revealed higher levels of basic FGF mRNA than normal mucosa, whereas only 3 (33%) of the 9 well differentiated adenocarcinomas studied produced similar results. Immunohistochemically, basic FGF protein was localized in tumor cells. These results suggest that basic FGF produced by tumor cells may play an important role in producing fibrosis and angiogenesis in gastric carcinomas.     

Expression of basic fibroblast growth factor in human gastric carcinomas.

The expression of mRNA for the basic fibroblast growth factor (FGF) gene was examined in seven human gastric carcinoma cell lines and in tissue from 29 gastric carcinomas together with the adjacent normal mucosa. Among the seven gastric carcinoma cell lines, the MKN45 cell line expressed mRNA for the basic FGF gene. Basic FGF protein production was confirmed by flow cytometric analysis and immunohistochemistry. Among the surgical specimens, 16 (55%) of 29 gastric carcinomas showed higher levels of basic FGF mRNA than the normal mucosa. Interestingly, in scirrhous gastric carcinomas characterized by their fibrous stroma and rapid growth, 9 (69%) of 13, samples examined revealed higher levels of basic FGF mRNA than normal mucosa, whereas only 3 (33%) of the 9 well differentiated adenocarcinomas studied produced similar results. Immunohistochemically, basic FGF protein was localized in tumor cells. These results suggest that basic FGF produced by tumor cells may play an important role in producing fibrosis and angiogenesis in gastric carcinomas.     

Complementary DNA cloning and sequencing of rat ovarian basic fibroblast growth factor and tissue distribution study of its mRNA

Three cDNA clones encoding rat basic fibroblast growth factor (FGF) were isolated from 10(6) independent clones prepared from a pregnant mare serum gonadotropin (PMSG)-stimulated rat ovarian cDNA library. One of the cDNA clones contained the entire coding sequence for basic FGF. The other two possessed the sequence coding the carboxy terminal 61 amino acids of rat basic FGF, the putative upstream intron sequence, and a 3'-noncoding region. The cDNAs encoding rat basic FGF predict a molecule consisting of 154 amino acid residues, which is one amino acid shorter than the human and bovine basic FGF. Otherwise, there are only 5 conservative amino acid substitutions between the rat and the human/bovine sequences. Poly A+ RNA from brain cortex and hypothalamus show a single 6.0 kb band that hybridizes to the cloned cDNA probe by Northern analyses. The observation that basic FGF mRNA is below the limits of detection in adrenal, spleen, heart, lung, kidney, liver, stomach, small intestine, large intestine, testis, and ovary support the notion that the that the high levels of the protein found in these tissues is due to storage of the mitogen in the extracellular matrix and not continuous gene expression. The significance of the abundance of mRNA in tissues which are not undergoing either active angiogenesis or cell proliferation (hypothalamus and brain cortex) is unclear but emphasizes the potential neuronotrophic function of basic FGF.     

Cultured human foreskin fibroblasts produce a factor that stimulates their growth with properties similar to basic fibroblast growth factor

Summary To determine if fibroblasts could be a source of fibroblast growth factor (FGF) in tissue, cells were initiated in culture from newborn human foreskin. Cells were studied in Passages 2 to 8. Fibroblast cell lysates promoted radiolabeled thymidine uptake by cultured quiescent fibroblasts. Seventy-nine percent of the growth-promoting activity of lysates was recovered from heparin-Sepharose. The heparin-binding growth factor reacted on immunoblots with antiserum to human placenta-derived basic FGF and competed with iodinated basic FGF for binding to antiserum to (1-24)bFGF synthetic peptide. To confirm that fibroblasts were the source of the growth factor, cell lysates were prepared from cells incubated with radiolabeled methionine. Heparin affinity purified material was immunoprecipitated with basic FGF antiserum and electrophoresed. Radiolabeled material was detected on gel autoradiographs in the same molecular weight region as authentic iodinated basic FGF. The findings are consistant with the notion that cultured fibroblasts express basic FGF. As these cells also respond to the mitogen, it is possible that the regulation of their growth is under autocrine control. Fibroblasts may be an important source of the growth factor in tissue. Supported in part by grant DK 31063 from the National Institutes of Health, Bethesda, MD.     

A rat Sertoli cell factor similar to basic fibroblast growth factor increases c-fos messenger ribonucleic acid in cultured Sertoli cells

We have shown that the cultured Sertoli cell from the immature rat contains a fibroblast growth factor (FGF)-like factor. It behaves as a cationic peptide, is a potent competence factor for BALB/c3T3 mouse embryo fibroblasts, and displays a high affinity for heparin. Both bovine basic FGF and Sertoli cell FGF-like factor rapidly increase c-fos mRNA in cultured Sertoli cells. FSH, serum, and phorbol esters individually stimulate c-fos in cultured Sertoli cells whereas platelet-derived growth factor, epidermal growth factor, and insulin-like growth factor-I have little affect. However, unlike FSH, basic FGF does not stimulate an increase in cAMP and unlike either serum or phorbol esters, basic FGF does not stimulate phosphoinositol turnover or intracellular calcium changes. When Sertoli cell protein kinase C activity is suppressed by preexposure to phorbol ester, basic FGF continues to be a potent stimulator of c-fos, indicating that the calcium/phospholipid pathway is not involved in FGF induction. Basic FGF and FSH also increase jun-B mRNA levels in cultured Sertoli cells. In response to FGF, jun-B is more transiently increased than c-fos. In contrast, in response to FSH, jun-B persists longer than c-fos. These results indicate that cultured Sertoli cells contain a FGF-like factor that increases c-fos mRNA via a mechanism not involving cAMP and the calcium/phospholipid pathways. The different responsiveness of c-fos and jun-B to FSH and basic FGF may explain differences in the ultimate actions of these two ligands.     

Basic fibroblast growth factor (FGF) promotes cartilage repair in vivo

Although it has been clearly established that basic fibroblast growth factor (FGF) is a potent mitogen for chondrocytes in vitro, there is little evidence that it can stimulate this cell type in vivo. In an effort to address this problem, we examined the effect of an intraarticular administration of basic FGF. Alzet osmotic pumps delivering the mitogen to the site of injury promotes the healing of intra-chondrial lesions by stimulating chondrocyte proliferation and the formation of extracellular matrix. The observation that chronic infusions of basic FGF can elicit a repair response at the site of injury suggests that this growth factor may have therapeutic applications that extend beyond its capacity to induce neovascularization. The results also suggest that one of the ways that the perichondrium mediates cartilage repair may be by the local production of FGF-like mitogens.     

Analysis of chromosome 22 deletions in neurofibromatosis type 2-related tumors.

The neurofibromatosis type 2 (NF2) gene has been hypothesized to be a recessive tumor suppressor, with mutations at the same locus on chromosome 22 that lead to NF2 also leading to sporadic tumors of the types seen in NF2. Flanking markers for this gene have previously been defined as D22S1 centromeric and D22S28 telomeric. Identification of subregions of this interval that are consistently rearranged in the NF2-related tumors would aid in better defining the disease locus. To this end, we have compared tumor and constitutional DNAs, isolated from 39 unrelated patients with sporadic and NF2-associated acoustic neuromas, meningiomas, schwannomas, and ependymomas, at eight polymorphic loci on chromosome 22. Two of the tumors studied revealed loss-of-heterozygosity patterns, which is consistent with the presence of chromosome 22 terminal deletions. By using additional polymorphic markers, the terminal deletion breakpoint found in one of the tumors, an acoustic neuroma from an NF2 patient, was mapped within the previously defined NF2 region. The breakpoint occurred between the haplotyped markers D22S41/D22S46 and D22S56. This finding redefines the proximal flanking marker and localizes the NF2 gene between markers D22S41/D22S46 and D22S28. In addition, we identified a sporadic acoustic neuroma that reveals a loss-of-heterozygosity pattern consistent with mitotic recombination or deletion and reduplication, which are mechanisms not previously seen in studies of these tumors. This finding, while inconsistent with models of tumorigenesis that invoke single deletions and their gene-dosage effects, lends further support to the recessive tumor-suppressor model.     

FGF modulates the PDGF-driven pathway of oligodendrocyte development

PDGF promotes the growth of oligodendrocyte type-2 astrocyte (O-2A) glial progenitor cells and allows their timely differentiation into oligodendrocytes, the CNS myelin-forming cells. We demonstrate that basic FGF is a potent mitogen for brain O-2A progenitor cells, but blocks their differentiation into oligodendrocytes. Treatment with basic FGF also influences the level of expression of PDGF receptors on O-2A progenitor cells. These cells express only the alpha chain PDGF receptor, and the levels of PDGF alpha receptors decrease as the cells differentiate. In contrast, basic FGF maintains a high level of functionally responsive PDGF alpha receptors in O-2A progenitors. Thus basic FGF activates a signaling pathway that can positively regulate PDGF receptors in O-2A progenitor cells. In this way basic FGF or an FGF-like factor may modulate the production of myelin-forming cells in the CNS.     

FGF9 is an autocrine and paracrine prostatic growth factor expressed by prostatic stromal cells

Polypeptide growth factors, including members of the fibroblast growth factor (FGF) family, play an important role in the growth and maintenance of the normal prostate. We have found that FGF9 is expressed at high levels in the normal peripheral and transition zone of the human prostate. Analysis of FGF9 production by primary cultures of prostatic epithelial and stromal cells has shown that FGF9 is produced and secreted by the prostatic stromal cells. Neither of these processes appears to be modulated by androgens. Production of FGF9 by stromal cells in vivo was confirmed by immunohistochemistry. FGF9 is a potent mitogen for both prostatic epithelial and stromal cells in culture and is a more potent mitogen for these cells than either FGF2 or FGF7, two other FGFs expressed in the human prostate. FGF9 is an abundant secreted growth factor that can act as both a paracrine mitogen for epithelial cells and an autocrine mitogen for stromal cells. Western blot analysis of tissue extracts from the normal and hyperplastic transition zone shows that FGF9 is present at two to threefold higher levels in the hyperplastic transition zone. Overexpression of this paracrine and autocrine growth factor may play an important role in the epithelial and stromal proliferation in benign prostatic hyperplasia. J. Cell. Physiol. 180:53–60, 1999. © 1999 Wiley-Liss, Inc.     

Up-regulation of fibroblast growth factor (FGF) receptor mRNA levels by basic FGF or testosterone in androgen-sensitive mouse mammary tumor cells.

Since we had previously shown that both basic fibroblast growth factor (bFGF) and testosterone stimulate the growth of mouse mammary carcinoma cells (SC-3) in serum-free culture, we tested the effect of bFGF or testosterone on FGF receptor mRNA levels. Northern blot analyses revealed that stimulation with bFGF resulted in a 5-fold increase in FGF receptor mRNA levels at 6-8 h followed by a decline to the unstimulated levels at 24 h. Simultaneous addition of cycloheximide blocked bFGF-induced accumulation of FGF receptor mRNA, although exposure of SC-3 cells to cycloheximide alone caused marginal increase in its basal level. Neither phorbol ester nor forskolin stimulated FGF receptor mRNA expression, but testosterone could raise FGF receptor mRNA levels. To obtain the maximum stimulation, however, testosterone required the longer stimulation period (12 h) than bFGF, suggesting that testosterone-induced FGF receptor mRNA accumulation is mediated through an induction of FGF-like growth factor.     

Signal transduction defect appears to be the cause of rat prostate cancer cell fibroblast growth factor insensitivity.

Using monolayer cultures of clonally isolated C3 and T5 rat prostate cancer cells, we determined that acidic (aFGF) and basic (bFGF) fibroblast growth factors profoundly enhanced T5 cell thymidine incorporation with half-maximum stimulation at 0.53 and 0.35 ng/ml, respectively. In contrast, aFGF or bFGF enhancement of C3 cell thymidine incorporation was about 5% of that of T5 cells, and effects were principally mitogen concentration independent. Saturation analyses and cross-linking studies established that both C3 and T5 cells contained high-affinity FGF receptors of 120 and 145 kilodaltons and that receptor content and Kd of C3 and T5 cells were comparable. aFGF or bFGF stimulation of T5 cell thymidine incorporation profoundly decreased as cell plating density was reduced from 1.5 x 10(5) to 1.0 x 10(4) cells/well. The modest response of C3 cells to either aFGF or bFGF also decreased as cell plating density was reduced. Because heparin preserves FGF biological activity and enhances bFGF binding to high-affinity FGF receptors, we examined the effect of heparin on FGF stimulation of C3 cell thymidine incorporation. We found that changes in cell plating density and/or medium heparin concentration had variable, inconsistent effects. These were C3 cell plating density associated and included inhibition or modest enhancement of FGF effects. Binding analyses established that high-affinity bFGF binding of C3 and T5 cells immediately prior to assessing FGF-stimulated thymidine incorporation was comparable and independent of cell plating density, implying that C3 cell FGF insensitivity was not attributable to differences in C3 and T5 cell FGF receptor content at the time of mitogen stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Basic fibroblast growth factor inhibits mineralization but induces neuronal differentiation by human dental pulp stem cells through a FGFR and PLCγ signaling pathway

Basic fibroblast growth factor (basic FGF) has pivotal roles in the function of various cell types. Here, we report the effects of basic FGF in the regulation of dental pulp stem cell (DPSC) behaviors including maintaining stemness and directing differentiation. Cells isolated from human dental pulp tissues exhibited stem cell properties including the expression of mRNA markers for embryonic and mesenchymal stem cells, the expression of Stro-1, and the multipotential differentiation. Basic FGF stimulated colony-forming units of DPSCs and up-regulated the expression of the embryonic stem cell markers; Oct4, Rex-1, and Nanog. Moreover, osteogenic medium containing basic FGF inhibited alkaline phosphatase enzymatic activity and mineralization of DPSCs. On the contrary, basic FGF appeared to be an influential growth factor in the neurogenic differentiation of DPSCs. In the presence of basic FGF, increased DPSCs neurosphere size and the up-regulation of neurogenic markers were noted. Inhibitors of FGFR or PLCγ were able to ablate the basic FGF-induced neuronal differentiation of DPSCs. Taken together, these results suggest basic FGF may be involved in the mechanisms controlling DPSCs cell fate decisions.     

Bovine brain and pituitary fibroblast growth factors: comparison of their abilities to support the proliferation of human and bovine vascular endothelial cells

The mitogenic effects of brain and pituitary fibroblast growth factors (FGF) on vascular endothelial cells derived from either human umbilical vein or bovine aortic arch have been compared. Both brain and pituitary FGF are mitogenic for low density human umbilical endothelial (HUE) cell cultures maintained on either fibronectin- or laminin-coated dishes or on biomatrices produced by cultured cells such as bovine corneal endothelial cells or the teratocarcinoma cell line PF-HR-9. Pituitary FGF triggered the proliferation of HUE cells at concentrations as low as 0.25 ng/ml, with a half-maximal response at 0.55 ng/ml and optimal effect at 2.5 to 5 ng/ml. It was 50,000-fold more potent than commercial preparations of endothelial cell growth factor and 40 times more potent than commercial preparations of pituitary FGF. Similar results were observed when the effect of pituitary FGF was tested on low density cultures of adult bovine aortic endothelial cells. When the activity of brain and pituitary FGF on low density HUE cell cultures was compared, both mitogens were active. To confirm the presence in brain extract of both acidic and neutral, as well as of basic mitogen, for HUE cells, brain tissues were extracted at acidic (4.5), neutral (7.2), and basic (8.5) pH. The three types of extracts were equally potent in supporting the proliferation of either HUE or adult bovine aortic endothelial cells. When the various extracts were absorbed at pH 6.0 on a carboxymethyl Sephadex C-50 column, the neutral and basic extracts had an activity after adsorption similar to that of unadsorbed extracts. In contrast, extracts prepared at pH 4.5 lost 90-95% of their activity which was recovered in the adsorbed fraction containing FGF.