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
References
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TL;DR: Investigating whether the expression in tumors of a secreted fibroblast growth factor-binding protein (FGF-BP) that mobilizes and activates locally stored FGFs can serve as an angiogenic switch molecule found that the reduction of FGF- BP reduced the release of biologically active basic FGF (bFGF) from cells in culture.
Abstract: The growth and metastatic spread of cancer is directly related to tumor angiogenesis, and the driving factors need to be understood to exploit this process therapeutically. However, tumor cells and their normal stroma express a multitude of candidate angiogenic factors, and very few specific inhibitors have been generated to assess which of these gene products are only innocent bystanders and which contribute significantly to tumor angiogenesis and metastasis. Here we investigated whether the expression in tumors of a secreted fibroblast growth factor (FGF)-binding protein (FGF-BP) that mobilizes and activates locally stored FGFs (ref. 11) can serve as an angiogenic switch molecule. Developmental expression of the retinoid-regulated FGF-BP gene is prominent in the skin and intestine during the perinatal phase and is down-modulated in the adult. The gene is, however, upregulated in carcinogen-induced skin tumors, in squamous cell carcinoma (SCC) and in some colon cancer cell lines and tumor samples. To assess the significance of FGF-BP expression in tumors, we depleted human SCC (ME-180) and colon carcinoma (LS174T) cell lines of their endogenous FGF-BP by targeting with specific ribozymes. We found that the reduction of FGF-BP reduced the release of biologically active basic FGF (bFGF) from cells in culture. Furthermore, the growth and angiogenesis of xenograft tumors in mice was decreased in parallel with the reduction of FGF-BP. This suggests that human tumors can utilize FGF-BP as an angiogenic switch molecule.
237 citations
233 citations
TL;DR: In an attempt to clone protein tyrosine kinases, antiphosphotyrosine antibodies were used to screen lambda gt11 cDNA expression libraries, and a 2.5-kilobase cDNA encoding a novel tyrosinesine kinase was isolated from a mouse liver cDNA library.
Abstract: In an attempt to clone protein tyrosine kinases, antiphosphotyrosine antibodies were used to screen lambda gt11 cDNA expression libraries. By this method, a 2.5-kilobase cDNA encoding a novel tyrosine kinase was isolated from a mouse liver cDNA library. This new gene is most closely related to the receptor tyrosine kinases ret, fms, and kit.
224 citations
"Fibroblast growth factors, their re..." refers background in this paper
...(1995) saw no direct interaction and instead proposed that, as the Tyr766 to Phe766 mutant had high levels of phosphorylated Src, the PLCγ pathway inhibits Src activity....
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...Cloning of the human FGF receptor (FGFR) genes identified the first two,fgfr-1 and fgfr-2, asflg and bek (Dionne et al. 1990), both of which were previously identified tyrosine kinase proteins (Kornbluth et al. 1988, Rutaet al. 1989)....
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TL;DR: Results indicate that signaling occurs partly through cell surface receptors and partly by transport of the growth factor into the cell as well as stimulated DNA synthesis in toxin-resistant cells lacking functional aFGF receptors while having a high number of diphtheria toxin receptors.
222 citations
"Fibroblast growth factors, their re..." refers background in this paper
...FGF-1 has also been shown to stimulate DNA synthesis without signaling through a cell-surface FGF receptor (Wiedlocha et al. 1994), suggesting that the nuclear localization signal may allow FGF-1 to act through an intracrine mechanism....
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213 citations
"Fibroblast growth factors, their re..." refers background in this paper
...One way these recruited target proteins may be localized to the activated receptor is through the interaction between their Src-homology 2 (SH2) domains and specific phosphotyrosine residues on the activated receptor (Pawson 1995)....
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...Phosphorylated tyrosine residues, in turn, recruit other signaling molecules to the activated receptors and propagate the signal through many possible transduction pathways (Pawson 1995)....
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