Fibroblast growth factors, their receptors and signaling.
TL;DR: FGF signaling also appears to play a role in tumor growth and angiogenesis, and autocrine FGF signaling may be particularly important in the progression of steroid hormone-dependent cancers to a hormone-independent state.
Abstract: Fibroblast growth factors (FGFs) are small polypeptide growth factors, all of whom share in common certain structural characteristics, and most of whom bind heparin avidly. Many FGFs contain signal peptides for secretion and are secreted into the extracellular environment, where theycan bind to the heparan-like glycosaminoglycans (HLGAGs) of the extracellular matrix (ECM). From this reservoir, FGFs mayact directlyon target cells, or theycan be released through digestion of the ECM or the activityof a carrier protein, a secreted FGF binding protein. FGFs bind specific receptor tyrosine kinases in the context of HLGAGs and this binding induces receptor dimerization and activation, ultimatelyresulting in the activation of various signal transduction cascades. Some FGFs are potent angiogenic factors and most playimportant roles in embry onic development and wound healing. FGF signaling also appears to playa role in tumor growth and angiogenesis, and autocrine FGF signaling maybe particularlyimportant in the progression of steroid hormone-dependent cancers to a hormone-independent state.
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TL;DR: A review of the specific roles of these growth factors and cytokines during wound healing can be found in this article, where patients are treated by three growth factors: PDGF-BB, bFGF, and GM-CSF.
Abstract: Wound healing is an evolutionarily conserved, complex, multicellular process that, in skin, aims at barrier restoration. This process involves the coordinated efforts of several cell types including keratinocytes, fibroblasts, endothelial cells, macrophages, and platelets. The migration, infiltration, proliferation, and differentiation of these cells will culminate in an inflammatory response, the formation of new tissue and ultimately wound closure. This complex process is executed and regulated by an equally complex signaling network involving numerous growth factors, cytokines and chemokines. Of particular importance is the epidermal growth factor (EGF) family, transforming growth factor beta (TGF-beta) family, fibroblast growth factor (FGF) family, vascular endothelial growth factor (VEGF), granulocyte macrophage colony stimulating factor (GM-CSF), platelet-derived growth factor (PDGF), connective tissue growth factor (CTGF), interleukin (IL) family, and tumor necrosis factor-alpha family. Currently, patients are treated by three growth factors: PDGF-BB, bFGF, and GM-CSF. Only PDGF-BB has successfully completed randomized clinical trials in the Unites States. With gene therapy now in clinical trial and the discovery of biodegradable polymers, fibrin mesh, and human collagen serving as potential delivery systems other growth factors may soon be available to patients. This review will focus on the specific roles of these growth factors and cytokines during the wound healing process.
2,617 citations
TL;DR: A subset of the FGF family, expressed in adult tissue, is important for neuronal signal transduction in the central and peripheral nervous systems.
Abstract: Fibroblast growth factors (FGFs) make up a large family of polypeptide growth factors that are found in organisms ranging from nematodes to humans. In vertebrates, the 22 members of the FGF family range in molecular mass from 17 to 34 kDa and share 13-71% amino acid identity. Between vertebrate species, FGFs are highly conserved in both gene structure and amino-acid sequence. FGFs have a high affinity for heparan sulfate proteoglycans and require heparan sulfate to activate one of four cell-surface FGF receptors. During embryonic development, FGFs have diverse roles in regulating cell proliferation, migration and differentiation. In the adult organism, FGFs are homeostatic factors and function in tissue repair and response to injury. When inappropriately expressed, some FGFs can contribute to the pathogenesis of cancer. A subset of the FGF family, expressed in adult tissue, is important for neuronal signal transduction in the central and peripheral nervous systems.
2,228 citations
TL;DR: It is concluded that FGF-21, which was discovered to be a potent regulator of glucose uptake in mouse 3T3-L1 and primary human adipocytes, exhibits the therapeutic characteristics necessary for an effective treatment of diabetes.
Abstract: Diabetes mellitus is a major health concern, affecting more than 5% of the population. Here we describe a potential novel therapeutic agent for this disease, FGF-21, which was discovered to be a potent regulator of glucose uptake in mouse 3T3-L1 and primary human adipocytes. FGF-21-transgenic mice were viable and resistant to diet-induced obesity. Therapeutic administration of FGF-21 reduced plasma glucose and triglycerides to near normal levels in both ob/ob and db/db mice. These effects persisted for at least 24 hours following the cessation of FGF-21 administration. Importantly, FGF-21 did not induce mitogenicity, hypoglycemia, or weight gain at any dose tested in diabetic or healthy animals or when overexpressed in transgenic mice. Thus, we conclude that FGF-21, which we have identified as a novel metabolic factor, exhibits the therapeutic characteristics necessary for an effective treatment of diabetes.
1,921 citations
TL;DR: Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning.
Abstract: The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs) Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer © 2015 Wiley Periodicals, Inc
1,445 citations
TL;DR: This study completes the mitogenesis-based comparison of receptor specificity of the entire FGF family under standard conditions and should help in interpreting and predicting in vivo biological activity.
1,052 citations
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TL;DR: These results suggest specific interactions between ECM or ECM components with BEL cell that restrain excessive cell spreading and restore an original polarized phenotype of the cells seen in vivo.
19 citations
Journal Article•
TL;DR: Determination of the structure of the FGF-3 transcripts indicates that they are generated by splicing of the three exons and termination at the single polyadenylation site predicted from the genomic sequence, and size heterogeneity is due to multiple initiation sites spanning a 700 base-pair long promoter region.
Abstract: The human colon carcinoma cell line, SW613-S, is composed of cells with a high-level amplification of the MYC proto-oncogene that are tumorigenic in nude mice and of cells with a low-level amplification of MYC that are not tumorigenic. Transcripts from FGF-3, a member of the fibroblast growth factor gene family, accumulate in cells from tumorigenic clones, but are undetectable in those from non-tumorigenic clones. Nuclear run-on analyses indicate that this differential FGF-3 expression is regulated at the level of transcription initiation. Determination of the structure of the FGF-3 transcripts indicates that they are generated by splicing of the three exons and termination at the single polyadenylation site predicted from the genomic sequence. Their size heterogeneity is due to multiple initiation sites spanning a 700 base-pair long promoter region. FGF-3 is activated in tumors induced in nude mice by MYC-transfected cells from non-tumorigenic clones. However, in most of the cell lines established from these tumors, FGF-3 expression tends to be lost upon in vitro propagation. Thus, in these transfectant cell lines, the presence of exogenous MYC gene copies is not sufficient to activate FGF-3 expression and in vivo growth is also required.
19 citations
"Fibroblast growth factors, their re..." refers background in this paper
...However, fgf-3 is consistently expressed in tumorigenic, but not non-tumorigenic, clones of human colon cancer cell lines (Galdemard et al. 1995), suggesting that it may be necessary, although not sufficient, for some tumors....
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TL;DR: Even though the MMTV promoter itself is weak without hormonal stimulation, viral integration can position the 5′ LTR elements to efficiently activate transcription from cellular proto-oncogenes, suggesting that the5′ elements of the LTR are the predominant determinants of the tissue- and orientation-specific activation of cellular promoters by MMTV.
Abstract: Integration of mouse mammary tumor virus (MMTV) near the int genes results in the inappropriate expression of these proto-oncogenes and initiates events that lead to the formation of mammary adenocarcinomas. In most cases, the MMTV provirus integrates in a transcriptional orientation opposite that of the int genes. We have used a novel, vector-based system designed to recapitulate the integration of MMTV upstream of the int-2 promoter. Compared to a cellular promoter or another retroviral promoter, the MMTV long terminal repeat (LTR) in this configuration is particularly efficacious at activating the int-2 promoter. The sequences responsible for enhancing the activity of the int-2 promoter map to two domains in the 5' end of the MMTV LTR. One domain is a previously defined element; the second is an element delineated by these studies that acts synergistically with the first. Both of these elements display mammary cell-specific activity. Thus, even though the MMTV promoter itself is weak without hormonal stimulation, viral integration can position the 5' LTR elements to efficiently activate transcription from cellular proto-oncogenes. Other functional elements in the LTR have little effect on the activation of the int-2 promoter. Even stimulation of the MMTV promoter with steroid hormones only modestly activates transcription from the int-2 promoter, suggesting that the 5' elements of the LTR are the predominant determinants of the tissue- and orientation-specific activation of cellular promoters by MMTV.
18 citations
"Fibroblast growth factors, their re..." refers background in this paper
...Normally the FGF-3 promoter is silent in adult animals, but the long terminal repeat (LTR) of the proviral MMTV is a strong activator of the FGF-3 promoter (Grimm & Nordeen 1998), driving expression of a gene more properly expressed during development....
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...…with androgens in both the human breast cancer cell line MDA-MB-231 and the 168 www.endocrinology.org SC-3 cell lines (Paysonet al.1996).fgf-8 was also identified as a frequently activated gene in tumors from MMTV-infected Wnt-1 transgenic mice, much likefgf-3 and fgf-4 (MacArthur et al. 1995b)....
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Journal Article•
TL;DR: HST-1/FGF-4 can regulate MK development not only as an MK potentiating factor, but also as an inducer of cytokine secretion from MK, and as a modulator of adhesive interactions with endothelial cells.
Abstract: Megakaryocyte (MK) development is dependent on the complex interaction of MK progenitors, various cytokines and stromal elements. We previously reported that an injection of replication-deficient adenovirus containing HST-1/FGF-4 cDNA (Adex1HST-1) into mice caused a twofold increase in peripheral platelet count for 30 days without any other hematological or histological abnormality. In the present study using Adex1HST-1-infected human megakaryocytic Dami cells, we demonstrated for the first time that HST-1/FGF-4 promoted MK maturation, inducing increases in DNA ploidy, cytoplasmic and membrane maturation, and platelet-like particle release. Moreover, HST-1/FGF-4 acted on megakaryocytic cells to induce secretion of IL-6 and TNF-alpha, and increased adhesion of megakaryocytic cells to human endothelial cells primarily via VLA-4 and LFA-1 molecules; both mechanisms have been shown to lead to MK maturation. We also showed that HST-1/FGF-4 stimulates the proliferation of MK progenitors not alone but synergistically with IL-3 via IL-6 and with c-mpl ligand (thrombopoietin) not via IL-6. This result supports the hypothesis of the presence of two distinct populations of MK progenitors: IL-3-dependent and Tpo-dependent. All these results suggest that HST-1/FGF-4 can regulate MK development not only as an MK potentiating factor, but also as an inducer of cytokine secretion from MK, and as a modulator of adhesive interactions with endothelial cells.
16 citations
"Fibroblast growth factors, their re..." refers background in this paper
...FGF-4 has been shown to stimulate the proliferation of megakaryocyte progenitor cells (Konishi et al. 1996) and FGF-2 knockout mice have abnormalities in their serum platelet levels (Zhouet al....
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TL;DR: The results indicate that a blockade of AIGF activity is an important therapeutic target and some compounds such as heparin and suramin are found to inhibit this androgen-induced autocrine loop.
16 citations
"Fibroblast growth factors, their re..." refers background in this paper
...†From Ornitz et al. (1996), except where stated; ‡From Koga et al. (1995); §From Miralles et al. (1999); ¶From Xu et al. (1999). topologically identical to interleukin-1β (IL-1β) (Zhu et al. 1991), with which some members also share the feature of secretion by an endoplasmic reticulum (ER)-Golgiindependent mechanism....
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...From the ER, proteins destined for secretion are transported to the Golgi apparatus and are eventually packaged into vesicles for secretion from the cell surface....
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...in itself sufficient to induce it (Koga et al. 1995), suggesting...
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...†From Ornitz et al. (1996), except where stated; ‡From Koga et al. (1995); §From Miralles et al. (1999); ¶From Xu et al. (1999). topologically identical to interleukin-1β (IL-1β) (Zhu et al. 1991), with which some members also share the feature of secretion by an endoplasmic reticulum…...
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...From this reservoir, FGFs may act directly on target cells, or they can be released through digestion of the ECM or the activity of a carrier protein, a secreted FGF binding protein....
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