Development of new cancer chemoprevention agents: role of pharmacokinetic/pharmacodynamic and intermediate endpoint biomarker monitoring

Dimerization is a prerequisite for many growth factors in their receptor activation leading to cellular response. FGF-1 and FGF-2, members of the Fibroblast Growth Factor (FGF) family, were shown to form non-covalent dimers and oligomers in vitro. Using the two-hybrid system as an in vivo binding assay we show here that of three representative members of the FGF family, only FGF-2 is able to homodimerize. Moreover the FGF-2 isoforms could heterodimerize. Two single-point mutants (T121F and W123R), defective in their dimerization capability, were isolated through random mutagenesis and were used to study the role of FGF-2 dimerization with regard to its biological activity. Remarkably, these mutant proteins were still able to induce cell differentiation, but were strongly affected in their capacity to promote cell proliferation. This study thus highlights the uncoupling between proliferation and differentiation FGF-2 signaling pathways and the crucial role of FGF-2 dimerization in the mitogenic activity of this factor.     

Identification and characterization of a novel member of the fibroblast growth factor family

A new member of the fibroblast growth factor (FGF) family, FGF-13, has been molecularly cloned as a result of high throughput sequencing of a human ovarian cancer cell library. The open reading frame of the novel human gene (1419 bp) encodes for a protein of 216 a.a. with a molecular weight of 22 kDa. The FGF-13 sequence contains an amino-terminal hydrophobic region of 23 a.a. characteristic of a signal secretion sequence. FGF-13 is most homologous, 70% similarity at the amino acid level, to FGF-8. Northern hybridization analysis demonstrated prominent expression of FGF-13 in human foetal and adult brain, particularly in the cerebellum and cortex. In proliferation studies with BaF3 cells, FGF-13 preferentially activates cell clones expressing either FGF receptor variant, 3-IIIc or 4. The signal transduction pathways of FGF-13 and FGF-2 were compared in rat hippocampal astrocytes. The two FGFs induce an equivalent level of tyrosine phosphorylation of mitogen-activated protein kinase (MAPK) and c-raf activation. However, FGF-13 is more effective than FGF-2 in inducing the phosphorylation of phospholipase C-gamma (PLC-gamma). Treatment of neuronal cultures from rat embryonic cortex with FGF-13 increases the number of glutamic acid decarboxylase immunopositive neurons, the level of high-affinity gamma-aminobutyric acid (GABA) uptake, and choline acetyltransferase enzyme activity. The GABAergic neuronal response to FGF-13 treatment is rapid with a significant increase occurring within 72 h. We have identified a novel member of the FGF family that is expressed in the central nervous system (CNS) and increases the number as well as the level of phenotypic differentiation of cortical neurons in vitro.     

A simple neonatal mock circulation enabling pulsatility and different hemodynamical states for neonatal ECMO research: application to assess the effect of a centrifugal pump operated neonatal ECMO system on the circulation

In the developing forebrain, mounting evidence suggests that neural stem cell proliferation and differentiation is regulated by growth factors. In vitro in the presence of serum, stem cell proliferation is predominantly mediated by fibroblast growth factor-2 (FGF-2) whereas neuronal differentiation can be triggered by FGF-1 in association with a specific heparan sulphate proteoglycan. On the other hand, astrocyte differentiation in vivo and in vitro appears to be dependent on signalling through the leukaemia inhibitory factor receptor (LIFR). The evidence suggests that in the absence of LIFR signalling, the stem cell population is present at approximately the same frequency and can generate neurons but is blocked from producing astrocytes that express glial fibrillary acidic protein (GFAP) or have trophic functions. The block can be overcome by other growth factors such as BMP-2/4 or interferon-gamma, providing further evidence that the inhibition to astrocyte development does not result from loss of a precursor population. Signalling through the LIFR, in addition to stimulating astrocyte differentiation, may also inhibit neuronal differentiation, which may explain why this receptor is expressed at the earliest stages of neurogenesis. Another signalling system which also exerts its influence on neurogenesis through active inhibition is Delta-Notch. We show in vitro that at high cell densities which impede neuronal production by FGF-1, lowering the levels of expression of the receptor Notch by antisense oligonucleotide results in a significant increase in neuronal production. Thus, stem cell differentiation appears to be dependent on the outcome of interactions between a number of signalling pathways, some which promote specific lineages and some which inhibit.     

Differential binding of fibroblast growth factor-2 and -7 to basement membrane heparan sulfate: comparison of normal and abnormal human tissues

Fibroblast growth factors (FGFs) play multiple roles during development and in adult tissues as paracrine regulators of growth and differentiation. FGFs signal through transmembrane receptor tyrosine kinases, but heparan sulfate is also required for signaling by members of the FGF family. In addition, heparan sulfate may be involved in determining tissue distribution of FGFs. Using biotinylated FGF-2 and FGF-7 (KGF) as probes, we have identified specific interactions between FGFs and heparan sulfates in human tissues. Both FGF species bind to tissue mast cells and to epithelial cell membranes. Binding to basement membrane heparan sulfate is tissue source dependent and specific. Although FGF-2 strongly binds to basement membrane heparan sulfate in skin and most other tissue sites examined, FGF-7 fails to bind to basement membrane heparan sulfate in most locations. However, in subendothelial matrix in blood vessels and in the basement membrane of a papillary renal cell carcinoma, strong FGF-7 binding is seen. In summary, distinct and specific affinities of heparan sulfates for different FGFs were identified that may affect growth factor activation and local distribution. Heparan sulfate may have a gatekeeper function to either restrict or permit diffusion of heparin-binding growth factors across the basement membrane.     

Molecular cloning of a novel cytokine cDNA encoding the ninth member of the fibroblast growth factor family, which has a unique secretion property

Glia-activating factor (GAF) is a novel heparin-binding growth factor purified from the culture supernatant of a human glioma cell line. It shows a spectrum of activity slightly different from those of other known growth factors. We have isolated the cDNA which encodes human GAF. A homology search revealed that GAF would be the ninth member of the FGF family, and we therefore call it FGF-9. The human FGF-9 cDNA cloned by using oligonucleotide probes encoded a polypeptide consisting of 208 amino acids. Sequence similarity to other members of the FGF family was estimated to be around 30%. Two cysteine residues and other consensus sequences in family members were also well conserved in the FGF-9 sequence. FGF-9 was found to have no typical signal sequence in its N terminus like those in acidic FGF and basic FGF. Acidic FGF and basic FGF are known not to be secreted from cells in a conventional manner. However, FGF-9 was found to be secreted from cells after synthesis despite its lack of a typical signal sequence. It could be detected exclusively in the culture medium of cDNA-transfected COS cells. The amino acid sequence of proteins purified from culture supernatant of the CHO cell line, which was cDNA transfected and selected as a high producer of FGF-9, showed that no peptides were cleaved from the N terminus except the initiation methionine. The rat FGF-9 cDNA was also cloned, and the structural analysis indicated that the PGF-9 gene is highly conserved. Expression of the FGF-9 gene could be detected in the brain and kidney of the adult rat. Restricted gene expression in organs and the unique secretion nature of the protein suggest that FGF-9 plays a physiological role which differs from those of well-characterized acidic FGF and basic FGF.     

Tissue culture assays using Caco-2 cell line differentiate virulent from non-virulent Listeria monocytogenes strains

OBJECTIVE: Fibroblast growth factor 9 (FGF-9) is a relatively new member of the FGF family isolated from the conditioned medium of a human glioblastoma cell line as a secreting type factor that exhibits a growth-stimulating effect on primary glial cells. To elucidate the roles of FGF-9 in human brain tumors, the expression and biological activities of FGF-9 were studied using culture cells and surgically obtained tumor specimens. METHODS: Measurement of FGF-9 and basic FGF in conditioned media of cell cultures was performed by using a sandwich enzyme immunoassay. The mitogenic effect of FGF-9 was evaluated by cell growth studies. FGF-9 expression in vivo was demonstrated by immunohistochemistry. RESULTS: One of 4 glioma cell lines and 4 of 16 human meningiomas examined actually secreted detectable amounts of FGF-9 proteins. In comparison, basic FGF production was detected from 3 of 4 glioma cell lines and 11 of 16 human meningiomas. Similarly to basic FGF, recombinant human FGF-9 significantly stimulated the in vitro cell proliferation in three of four glioma cell lines investigated in a dose-dependent manner. A time course growth study using U87 MG cells revealed an accelerated growth stimulation by FGF-9 after Day 4. The growth stimulatory activity was also shown in three of four human meningiomas studied. Moderate to strong immunoreactivity for FGF-9 was observed in 40 (82%) of 49 human brain tumors examined irrespective of origin, tumor type, grade of malignancy, or whether initial or recurrent. In contrast, strong immunostaining was localized in neurons in the normal human cerebral cortex. CONCLUSION: The present findings suggest that FGF-9 may be involved in the biology of human brain tumors with a possible importance in tumor cell growth. Whether the growth factor is more generally involved in oncogenesis of human tumors awaits further investigation.     

Characterization of GH3 cells overexpressing basic fibroblast growth factor (FGF-2)

Basic fibroblast growth factor (FGF-2) is not only a potent mitogen for various cells but also a multifunctional factor with angiogenic and chemotactic activity, and the capacity to induce the synthesis of various proteinases and to modulate endocrine function. To clarify the role played by FGF-2 in the progression of pituitary tumor, we fused rat FGF-2 cDNA to the promoter SR alpha, consisting of the early promoter of SV40 and HTLV(I)-LTR, and we cotransfected GH3 cells with pSV2-neo by an electroporation method. After selection by G418, we obtained 7 neomycin-resistant clones. Southern blot analysis of genomic DNA revealed the presence of transfected rat FGF-2 cDNA in 4 of the 7 clones. To measure FGF-2 molecules, we established a new immuno-fluorometric assay system, using 3 monoclonal antibodies against different portions of human FGF-2. This assay had a minimum sensitivity of 10 pg/ml and cross-reacted neither with acidic fibroblast growth factor (FGF-1) nor insulin-like growth factor 1 (IGF-1), even at a concentration of 100 ng/ml. Although FGF-2 was undetectable in the culture medium of any of the clones, the cell homogenate contained a significant amount of FGF-2 (7.2 ng/mg protein) in 1 of the 4 FGF-2-transfected clones (GH3FGF(+)), whereas FGF-2 was not detected (< 5.2 pg/mg protein) in the cell homogenates of either the parent GH3 cells or the control cells transfected with pSV2-neo alone (GH3FGF(-)), GH3FGF(+) grew as adherent cells and formed epithelial sheets with a growth rate similar to that of control cells. The amount of prolactin(PRL) released by TRH was greater in GH3FGF(+) than that in GH3 or GH3FGF(-). On the other hand, the sensitivity to SRIF was increased in GH3FGF(+) compared with that in other clones. The findings of these in vitro studies indicate that FGF-2, if it is expressed in pituitary tumor cells, plays little if any role in cell growth but may modulate certain cell functions such as responsiveness to hormones.     

Kinetics of conformational changes associated with potassium binding to and release from Na+/K(+)-ATPase

Previous studies have demonstrated that embryonal carcinoma (EC) cells express both fibroblast growth factor-4 (FGF-4) and FGF receptors. It has also been established that differentiation of EC cells represses the expression of the FGF-4 gene. Currently, the role of FGF-4 in the growth and differentiation of EC cells is unclear. In this study, we examined whether the differentiation of EC cells requires the repression of FGF-4 expression. To address this and related questions, F9 EC cells were transfected with an expression vector that uses the human beta-actin promoter to drive the constitutive expression of recombinant FGF-4. Unlike their untransfected counterparts, F9 EC cells transfected with this plasmid continue to produce recombinant FGF-4 after they differentiate. However, constitutive expression of this growth factor does not block morphological differentiation of the cells, nor does it alter the expression of six genes regulated by the differentiation of EC cells. Constitutive expression of recombinant FGF-4 also did not noticeably alter the growth of the transfected F9 EC cells before or after differentiation. Furthermore, unlike immortalized fibroblasts, which are known to grow in soft agar after transfection with FGF-4 expression plasmids, continued expression of recombinant FGF-4 activity did not enhance the ability of the EC-derived differentiated cells to form colonies in soft agar. These findings argue that continuous expression of recombinant FGF-4 activity does not block the differentiation of EC cells and that repression of the FGF-4 gene after EC cells differentiate does not appear, on its own, to be responsible for the loss of tumorigenicity that accompanies the differentiation of EC cells.     

L-deprenyl potentiates cAMP-induced elevation of FGF-2 mRNA levels in rat cortical astrocytes

The expression of fibroblast growth factor-2 (FGF-2, basic FGF) is up-regulated in astroglial cells by different stimuli, including glucocorticoid hormones and agents that cause an increase in cyclic AMP (cAMP) levels. In the present study we showed that L-deprenyl, a drug able to rescue neurons from potentially lethal damage, can potentiate FGF-2 induction by 8Br-cAMP in cultured astrocytes. This effect appears to be independent from its well known inhibitory activity on monoamine oxidase (MAO) type B. As astrocyte activation is an important step in response to neuronal injury, our data suggest that potentiation of neurotrophic factor expression may exert neuroprotection and therefore limit the progression of neuronal damage in several pathological situations.     

Suppression of fibroblast growth factors 1 and 2 by antisense oligonucleotides in embryonic chick retinal cells in vitro inhibits neuronal differentiation and survival

As retinal histogenesis proceeds there is a pronounced increase in the expression of fibroblast growth factor (FGF), reaching its maximum in the mature retina and largely in terminal differentiated retinal neurons. Recent in vivo evidence suggests that exogenous FGF functions as a differentiation and survival factor for a wide variety of cell types including CNS neurons and that endogenous FGF may perform similar functions. We have examined the consequences of selectively and independently inhibiting FGF1 or FGF2 expression using antisense oligonucleotides in embryonic chick retinal cells, differentiating in vitro. Whether FGF1 or FGF2 expression was inhibited the results were the same: a marked reduction in neuronal photoreceptor cells differentiation, an increase in programmed cell death, but no effects on cell proliferation. Even although these two related factors promote the same final effect on retinal cells, namely, neuronal differentiation and survival, their normal combined activities or levels appear to be important in achieving this effect. Stimulation with either exogenous FGF1 or FGF2 served to increase endogenous levels of both FGF1 and FGF2 and reversed the effects of antisense blockade of either FGF1 or FGF2. Our data suggest that although other sources of FGF exist within the eye, the function of endogenous FGF in differentiating retinal neurons may be to stimulate their differentiation and promote their survival.     

Distribution of fibroblast growth factor (FGF)-2 and FGF receptor-1 messenger RNA expression and protein presence in the mid-trimester human fetus

Fibroblast growth factors (FGF) are known to have key roles in embryonic growth and morphogenesis, but their presence and contributions to fetal development are unclear. In particular, little information exists as to the relevance of FGF and their specific receptors to human fetal development. We studied the anatomical distribution of messenger RNA encoding FGF-2 and one of its high affinity receptors, FGFR1, using in situ hybridization in a variety of human fetal tissues in early second trimester. Corresponding protein distributions were determined by immunohistochemistry. Both FGF-2 and FGFR1 mRNA and proteins were found to be present in every organ and tissue examined, but with defined cellular localizations. In skeletal muscle, both FGF-2 and FGFR1 mRNA and peptides were present in differentiated fibers, and both co-localized to proliferating chondrocytes of the epiphyseal growth plate. FGF-2 and FGFR1 mRNA and peptides were also present within cardiac or gastrointestinal smooth muscle. Within the gastrointestinal tract FGF-2 mRNA and peptide were located in the submucosal tissue, whereas FGFR1 was expressed within the overlying mucosa. Similarly, in skin, FGF-2 was expressed within the dermis whereas FGFR1 mRNA and peptide were most apparent in the stratum germinativum of the epidermis. In kidney and lung, FGFR1 mRNA was located in the tubular and alveolar epithelia respectively, whereas FGF-2 was expressed in both epithelial and mesenchymal cell populations. Both growth factor and receptor were widespread in both neuroblasts and glioblasts in the cerebral cortex of the brain. Immunoreactivity for FGF-2 and FGFR1 was seen in all vascular endothelial cells of major vessels and capillaries. Within the skin, kidney, lung, and intestine FGF-2 immunoreactivity was found in basement membranes underlying epithelia, and was associated with the extracellular matrix and plasma membranes of many cell types. The results show that FGF-2 and one of its receptors are widely expressed anatomically in the mid-trimester human fetus.     

Characterization of recombinant human fibroblast growth factor (FGF)-10 reveals functional similarities with keratinocyte growth factor (FGF-7)

A newly identified member of the fibroblast growth factor (FGF) family, designated FGF-10, is expressed during development and preferentially in adult lung. The predicted FGF-10 protein is most related to keratinocyte growth factor (KGF, or FGF-7). The latter is unique among FGFs in that it binds and signals only through the FGF receptor (FGFR2b) isoform KGF receptor (KGFR) expressed specifically by epithelial cells. In order to examine the biological and biochemical properties of human FGF-10, we isolated the cDNA and expressed its encoded protein in bacteria. The recombinant protein (rFGF-10) was a potent mitogen for Balb/MK mouse epidermal keratinocytes with activity detectable at 0.1 nM and maximal at around 5 nM. Within this concentration range, FGF-10 did not stimulate DNA synthesis in NIH/3T3 mouse fibroblasts. rFGF-10 bound the KGFR with high affinity comparable to that of KGF, and did not bind detectably to either the FGFR1c (Flg) or FGFR2c (Bek) receptor isoforms. The mitogenic activity of FGF-10 could be distinguished from that of KGF by its different sensitivity to heparin and lack of neutralization by a KGF monoclonal antibody. These results indicate that FGF-10 and KGF have similar receptor binding properties and target cell specificities, but are differentially regulated by components of the extracellular matrix.     

Expression of receptors for basic fibroblast growth factor on human periodontal ligament cells

Basic fibroblast growth factor (FGF-2; bFGF) is a major mitogen for connective tissue cells, and participates in the healing process. It has already been reported that FGF-2 could be applicable to enhance periodontal regeneration. In the present study, we examined FGF receptor (FGFR) expression on human periodontal ligament (PDL) cells. The binding of [125I]-labeled FGF-2 to human PDL cells was studied by radioreceptor assay. The binding of [125I]-FGF-2 to PDL cells reached a plateau after 2.5 h incubation at 4 degrees C and was inhibited by the addition of unlabeled FGF-2 and acidic FGF (FGF-1; aFGF), but not insulin-like growth factor-I, platelet-derived growth factor and transforming growth factor-beta 1. Scatchard analysis revealed the presence of approximately 1.0 x 10(5) FGF-2 binding sites per cell with an apparent Kd of 1.2 x 10(-10) M. Interestingly, the binding of [125I]-FGF-2 on PDL cells reached its maximum at d 6 of the culture and then gradually decreased. Scatchard analysis also demonstrated that the number of FGFRs on a PDL cell was altered during the course of the culture, while the affinity between FGF-2 and its receptor was not. The responsiveness of PDL cells to FGF-2, which was monitored by the inhibitory effect on alkaline phosphatase activity, was reduced in proportion to the decrease in the number of FGFRs on the PDL cells. The present study suggests that PDL cells alter the responsiveness to FGF-2 during the course of the culture by changing the density of its receptor, and that the density of FGFR expression might be a marker of the cytodifferentiation of PDL cells into mineralized tissue forming cells.     

Mouse fibroblast growth factor 10: cDNA cloning, protein characterization, and regulation of mRNA expression

Fibroblast growth factor 7 (FGF-7) or keratinocyte growth factor (KGF), is a potent and specific mitogen for epithelial cells. We have recently identified a novel human FGF-7 homologue, named FGF-10. To study the expression of this new FGF family member and its regulation in wound repair, we cloned the mouse FGF-10 (mFGF-10) cDNA. The encoded protein is 92% identical to human FGF-10 and 91% identical to rat FGF-10. When expressed in mammalian 293 cells, the mFGF-10 protein was glycosylated but remained cell- or extracellular matrix-associated. Upon addition of heparin, mFGF-10 protein was released into the media. mRNA encoding mFGF-10 was relatively abundant in lung, skin, brain and heart. In the skin, both FGF-7 and mFGF-10 were expressed in the dermal, but not the epidermal compartment. In contrast to FGF-7, mFGF-10 expression was not induced during cutaneous wound repair. In cultured fibroblasts, expression of mFGF-10 was strongly repressed by transforming growth factor beta and tumor necrosis factor alpha, whereas epidermal growth factor and interleukin-1beta had no effect. These results demonstrate a differential regulation of mFGF-10 and FGF-7 expression in vitro and during the wound healing process.     

alphavbeta3 integrin mediates the cell-adhesive capacity and biological activity of basic fibroblast growth factor (FGF-2) in cultured endothelial cells

Fibroblast growth factor-2 (FGF-2) immobilized on non-tissue culture plastic promotes adhesion and spreading of bovine and human endothelial cells that are inhibited by anti-FGF-2 antibody. Heat-inactivated FGF-2 retains its cell-adhesive activity despite its incapacity to bind to tyrosine-kinase FGF receptors or to cell-surface heparan sulfate proteoglycans. Recombinant glutathione-S-transferase-FGF-2 chimeras and synthetic FGF-2 fragments identify two cell-adhesive domains in FGF-2 corresponding to amino acid sequences 38-61 and 82-101. Both regions are distinct from the FGF-receptor-binding domain of FGF-2 and contain a DGR sequence that is the inverse of the RGD cell-recognition sequence. Calcium deprivation, RGD-containing eptapeptides, soluble vitronectin (VN), but not fibronectin (FN), inhibit cell adhesion to FGF-2. Conversely, soluble FGF-2 prevents cell adhesion to VN but not FN, thus implicating VN receptor in the cell-adhesive activity of FGF-2. Accordingly, monoclonal and polyclonal anti-alphavbeta3 antibodies prevent cell adhesion to FGF-2. Also, purified human alphavbeta3 binds to immobilized FGF-2 in a cation-dependent manner, and this interaction is competed by soluble VN but not by soluble FN. Finally, anti-alphavbeta3 monoclonal and polyclonal antibodies specifically inhibit mitogenesis and urokinase-type plasminogen activator (uPA) up-regulation induced by free FGF-2 in endothelial cells adherent to tissue culture plastic. These data demonstrate that FGF-2 interacts with alphavbeta3 integrin and that this interaction mediates the capacity of the angiogenic growth factor to induce cell adhesion, mitogenesis, and uPA up-regulation in endothelial cells.     

A functional fibroblast growth factor-1 immunoglobulin fusion protein

Proteins of the fibroblast growth factor (FGF) family play diverse roles in embryonic development, angiogenesis, and wound healing. The most well studied targets of FGF activity typically are cells of mesodermal and neuroectodermal origin; in addition, expression of FGF-1 (acidic FGF) is increased at several sites of chronic immunologic injury, and recent studies show that FGF-1 also may interact with cells of the immune system. In some human T cells, FGF-1 can induce signals necessary for production of interleukin-2, a key cytokine required for T cell proliferation. To better characterize the interaction of FGF-1 with FGF receptors on T cells, a fusion protein was constructed containing a portion of the constant region of human IgG1 (Fc) at the amino terminus of FGF-1. The Fc-FGF-1 fusion protein retained FGF function as determined by stimulation of tyrosine phosphorylation and DNA synthesis in NIH 3T3 cells. Binding of the intact fusion protein to FGF receptor 1 (FGFR1) on T cells was demonstrated by immunoprecipitation of the receptor bound to Fc-FGF-1 and by flow cytometry showing binding of fusion protein to T cells expressing FGFR1. This functional Fc-FGF-1 protein should prove useful in identifying FGFR-expressing cells.     

FGF-18, a novel member of the fibroblast growth factor family, stimulates hepatic and intestinal proliferation

The fibroblast growth factors (FGFs) play key roles in controlling tissue growth, morphogenesis, and repair in animals. We have cloned a novel member of the FGF family, designated FGF-18, that is expressed primarily in the lungs and kidneys and at lower levels in the heart, testes, spleen, skeletal muscle, and brain. Sequence comparison indicates that FGF-18 is highly conserved between humans and mice and is most homologous to FGF-8 among the FGF family members. FGF-18 has a typical signal sequence and was glycosylated and secreted when it was transfected into 293-EBNA cells. Recombinant murine FGF-18 protein (rMuFGF-18) stimulated proliferation in the fibroblast cell line NIH 3T3 in vitro in a heparan sulfate-dependent manner. To examine its biological activity in vivo, rMuFGF-18 was injected into normal mice and ectopically overexpressed in transgenic mice by using a liver-specific promoter. Injection of rMuFGF-18 induced proliferation in a wide variety of tissues, including tissues of both epithelial and mesenchymal origin. The two tissues which appeared to be the primary targets of FGF-18 were the liver and small intestine, both of which exhibited histologic evidence of proliferation and showed significant gains in organ weight following 7 (sometimes 3) days of FGF-18 treatment. Transgenic mice that overexpressed FGF-18 in the liver also exhibited an increase in liver weight and hepatocellular proliferation. These results suggest that FGF-18 is a pleiotropic growth factor that stimulates proliferation in a number of tissues, most notably the liver and small intestine.     

Itraconazole oral solution versus clotrimazole troches for the treatment of oropharyngeal candidiasis in immunocompromised patients

The development of the nervous system appears to be under the control of multiple growth factors, neurotrophins and cytokines, which may be expressed either continuously or transiently throughout defined stages of cellular generation, proliferation or differentiation. Fibroblast growth factor (FGF) cytokines and their receptors are abundantly expressed in the embryonic nervous system but their localization at autonomic levels in the fetal spinal cord has not yet been detailed. Immunoreactivity to FGF-2, probably the best characterized member of the FGF family (FGF-1 to FGF-10) and of one of its high affinity receptors, FGFR-1, was found in autonomic neurons at embryonic day E14, the peak day of generation and proliferation in the common ventral motoneuron pool. It was also continuously present throughout the investigated subsequent stages (E15 to postnatal day P30). Immunogold electron microscopy revealed the cytoplasmic localization of FGF-2 and FGFR-1 in intermediolateral neurons, the major group of sympathetic preganglionic neurons in the spinal cord. In these neurons, immunocytochemistry from E14 onwards showed the co-distribution of both markers at the period of axonal outgrowth to peripheral targets, e.g. the adrenal medulla. Our findings suggest autocrine and/or paracrine actions of FGF-2 for sympathetic preganglionic development but do not support its role as a target-derived neurotrophic factor for autonomic neuron development.