ARTICLE |
Correspondence to: Siân E. Hughes, Div. of Histopathology, UMDS, St Thomass Campus, Lambeth Palace Road, London SE1 7EH, UK.
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Summary |
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This report describes a systematic analysis of the expression of the fibroblast growth factor receptor (FGFR) multigene family (FGFR1, FGFR2, FGFR3, and FGFR4) in archival serial sections of normal human adult tissues representing the major organ systems, using immunohistochemical techniques. Polyclonal antisera specific for FGFR1, FGFR2, FGFR3, and FGFR4 and a three-stage immunoperoxidase technique were employed to determine the cellular distribution of these receptors at the protein level. The expression profiles for the tissue-specific cellular localization of the FGFR multigene family demonstrated widespread and striking differential patterns of expression of individual receptors in the epithelia and mesenchyme of multiple tissues (stomach, salivary glands, pancreas, thymus, ureter, and cornea) and co-expression of FGFR1-4 in the same cell types of other tissues. The widespread expression of FGFR1-4 in multiple organ systems suggests an important functional role in normal tissue homeostasis. Differences in the spatial patterns of FGFR gene expression may generate functional diversity in response to FGF-1 and FGF-2, both of which bind with equally high affinity to more than one receptor subtype. In vivo, this may lead to functional differences that are crucial for the regulation of normal physiological processes and are responsible for the pathological mechanisms that orchestrate various disease processes. (J Histochem Cytochem 45:1005-1019, 1997)
Key Words: immunolocalization, human tissues, fibroblast growth factor receptor, differential expression
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Introduction |
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The fibroblast growth factors (FGFs) constitute a family of at least nine structurally related heparin-binding polypeptide mitogens which can induce diverse cellular responses in multiple biological systems. The best-characterized family members are the prototypes FGF-1 (
The FGFs mediate their biological effects by binding to high-affinity cell-surface receptors with protein tyrosine kinase activity. Four receptors have been identified in the human. These include FGFR1 (
FGF-FGFR interactions are extremely complex. Individual receptors show specific patterns of expression in adult tissues and during development (
Despite major progress in the characterization of the FGFR multigene family, there are limited data regarding the tissue-specific cell distribution of individual receptors in normal human adult tissues at the protein level. In the currently available reports that have specifically addressed this issue in human and murine tissues, techniques such as reverse transcriptase polymerase chain reaction (RT-PCR) (
More extensive in situ hybridization analyses specifically evaluating the tissue-specific cell distribution of FGFR mRNA transcripts in a wider range of tissues have been confined largely to the mouse (
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Materials and Methods |
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Tissue Preparation
Formalin-fixed, wax-embedded normal human tissues representing the major organ systems were selected from the surgical diagnostic files of the Department of Histopathology, St Thomas's Campus, UMDS, London. A series of fresh normal human tissues (tonsil, skin, colon, skeletal muscle) was obtained at surgical resection and snap-frozen in liquid nitrogen-cooled isopentane. These tissues were embedded in OCT before storage at -70C. Serial sections from frozen and wax-embedded tissues were cut at 5 µm and 4 µm, respectively, and mounted on silane-coated slides (Sigma; Poole, UK) before use in immunohistochemistry. In addition, the effects of different fixatives were evaluated in the panel of fresh frozen tissues. Cryostat sections were fixed in either ice-cold acetone, acetone:methanol (1:1), methanol, or formalin for 10 minutes before immunostaining.
Cell Culture
The following cell lines were grown in 150-mm dishes for the preparation of protein lysates for immunoblotting experiments: human stomach cancer cells (Kato III), human chronic myeloid leukemia cells (K-562), human umbilical vein endothelial cells (ECV304), FGFR1-transfected (L631) and parental (L6V) rat skeletal muscle myoblasts, FGFR4-transfected (F4) and parental (Neo) murine NIH3T3 fibroblasts. Kato III, L6V, and L631 skeletal muscle myoblasts, Neo and F4 NIH3T3 cells were grown in DMEM supplemented with 10% fetal calf serum (FCS) in 10% CO2/90% air. ECV304 and K-562 cells were grown in Medium 199 and RPMI supplemented with 10% FCS, respectively. ECV304 cells were maintained in 5% CO2/95% air and K-562 cells in 10% CO2/90% air at 37C. Media and FCS were purchased from Gibco (Paisley, Renfrewshire, UK). K-562 cells, FGFR1 and FGFR4 overexpressing cell lines, and Kato III cells were kindly provided by Dr. J. Knight, Department of Histopathology, St Thomas's Campus, UMDS, London; Dr. N. Lemoine, ICRF Oncology Group, Hammersmith Hospital, London; and Dr. Andrew Stubbs, Department of Gastroenterology, Guy's Campus, UMDS, London, respectively. ECV304 cells were purchased from the European Collection of Animal Cell Cultures (ECACC; Salisbury, Wiltshire, UK) No. 92091712.
Antibodies
Rabbit polyclonal antibodies raised against synthetic residues 808-822 of human flg gene product/FGFR1 (
Western Blotting
To confirm the specificities of the anti-FGFR1 and anti-FGFR4 antibodies, immunoblot analyses using protein lysates prepared from FGFR1 and FGFR4 overexpressing cell lines were carried out. For the anti-FGFR3 and anti-FGFR2 antisera, protein lysates from the chronic myeloid leukemic cell line K-562 (
Immunocytochemistry
Immunostaining was performed using a sensitive three-layer avidin-biotin complex (ABC) method with the rabbit IgG Vectastain Elite ABC (peroxidase) kit as outlined by the manufacturer (Vector Laboratories). Before application of normal goat serum, fixed and unfixed frozen sections were immersed in PBS, pH 7.4. Similarly, paraffin sections were dewaxed in xylene and hydrated through graded alcohols to water, then subsequently placed in PBS. To optimize immunostaining with the anti-human FGFR2 antiserum, enzymatic predigestion of paraffin sections with 0.01% protease XXIV (Sigma) was carried out for 15, 10, and 5 min at 37C, respectively. Optimal digestion of tissue sections was obtained with 0.01% protease for 10 min at 37C. Proteolytic digestion of tissue sections for the other FGFR antisera was found in earlier experiments not to improve immunostaining. Primary anti-FGFR1-4 antisera were diluted in PBS/0.3% BSA and used at predetermined optimal dilutions of 1:700 (anti-FGFR1), 1:200 (anti-FGFR2), 1:50 (anti-FGFR3), and 1:100 (anti-FGFR4). After overnight incubation at 4C, sections were rinsed in PBS and incubated for 1 hr at 22C with a biotinylated goat anti-rabbit antibody. Endogenous peroxidase was quenched by incubation in 0.3% hydrogen peroxide in methanol for 30 min; sections were rinsed in PBS and incubated for 30 min with the ABC solution. After further washes in PBS, the reaction product was visualized using diaminobenzidine (Sigma) as chromogen. Sections were counterstained with Harris's hematoxylin, dehydrated in graded alcohols, cleared in xylene, and mounted.
Controls
Control immunocytochemical experiments were performed by substitution of the primary antibody with normal rabbit serum at the same concentration as that of the respective primary antisera or by preincubation of the primary anti-FGFR1-4 antiserum with a molar excess of the corresponding synthetic peptide antigen (NBS Biologicals) used for immunization. Because of the high overall structural homology and the similar molecular weights of the FGFR family members, which limits Western analysis, additional cross-blocking peptide antigen neutralization experiments were performed. In these experiments, the respective primary anti-FGFR1-4 antisera were preincubated with a molar excess of either the corresponding or reciprocal peptide synthetic antigens in serial sections from tissues known to preferentially express individual receptors.
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Results |
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Specificity of Antibodies
The specificities of the the anti-human FGFR1-4 antibodies were confirmed by 8% SDS-PAGE using protein lysates prepared from cell lines known to preferentially express individual receptors and cell lines transfected with human FGFR1 and FGFR4 cDNA constructs. The FGFR1 antiserum recognized protein bands of 130 and 150 kD in lysates from rat L6 skeletal myoblasts overexpressing FGFR1 protein (Figure 1). Likewise, in lysates from FGFR4-transfected murine NIH3T3 fibroblasts, the anti-FGFR4 antibody recognized protein bands of 110 and 95 kD (Figure 2). The FGFR2 and FGFR3 antisera recognized protein bands of 135 kD and 115 kD in Kato III cell lysates and of 135, 125, and 97 kD in K-562 cell lysates, respectively (data not shown). These antibody-reactive bands were not observed in the nontransfected parental cell lines or in duplicate blots probed with irrelevant FGFR antisera or nonimmune normal rabbit serum (
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Moreover, other investigators have used identical synthetic peptide antigens to those employed in this study to generate specific polyclonal antisera to FGFR1 and FGFR2 (
Tissue Distribution
All four receptors were found to have distinct spatial patterns of distribution in many tissues, and the results in human tissues are summarized in Table 1. The most widespread expression was observed for FGFR1 and FGFR2. High levels of immunoreactive FGFR1 were seen in the skin, cornea, lung, heart, placenta, kidney, and ureter, and moderate levels in testis and ovary. Abundant FGFR2 expression was found in the prostate and stomach. In contrast, no expression was seen in the pancreas, ovary, cornea, and placenta. FGFR3 and FGFR4 exhibited more restricted patterns of tissue distribution. Marked FGFR3 positivity was seen in the appendix, colon, liver, sublingual gland, placenta, and cervix, although the overall intensity of immunostaining for FGFR3 was found to be much lower in the majority of tissues and associated vasculature compared with that of FGFR1, FGFR2, and FGFR4. Tissues exhibiting minimal or no FGFR3 expression included the stomach, duodenum, ileum, kidney, ureter, and ovary. Prominent expression of FGFR4 was observed in the liver, sublingual gland ducts, kidney, and ureter, as well as in the media of some (but not all) arterioles and veins in most tissues. A far higher proportion of tissues lacked immunoreactive FGFR4 compared with the proportion of tissues showing nonreactivity for the other receptors. FGFR4 has been shown to bind FGF-1 with higher affinity than FGF-2 (
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The degree of immunoreactivity, reflecting differences in the amount of protein expressed at the cellular level, varied qualitatively from intense to moderate or low in many of the tissues examined. The various degrees of cellular positivity both within and between given tissues for the same and different FGFRs are in concordance with the findings of other investigators (
Skin
The anti-human FGFR1 antibody revealed widespread strong staining for this receptor in the epidermis and appendages of the skin and in the media of dermal arterioles, veins, and microvasculature. Similarly, with the anti-human FGFR3-4 antisera, the patterns of immunostaining in the vasculature were practically concordant with those obtained for FGFR1, the principal exceptions being the lack of expression of these receptors in the epidermis. FGFR2 was expressed in the epidermis and dermal fibroblasts.
Urinary System
Distinct differences in FGFR expression were also detected in the ureter. Prominent immunoreactivity for FGFR4 was seen in both the urothelium and muscularis of the ureter (Figure 3A). This was in sharp contrast to the intense urothelial expression of FGFR1 and lack of reactivity in the muscularis (Figure 3B). In kidney, the tubule epithelium showed variable levels of FGFR expression. The strongest expression was that for FGFR4 (Figure 4), with intermediate and low levels of immunoreactive FGFR1 and FGFR2, respectively.
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Female and Male Reproductive Tracts
In the oviduct and ovary, spatial differences in FGFR expression were observed. Widespread expression of FGFR2 was seen in the epithelia of the oviduct and throughout the tissue vasculature, but in the ovary there was little staining for this receptor. FGFR4 was not expressed in the oviduct, but focal immunoreactivity for FGFR1 and FGFR3 was seen in the epithelia and occasional blood vessel of this tissue. In the ovary there was widespread expression of FGFR1 in stromal fibroblasts. Perhaps the most unusual receptor distribution was seen in the cervix, where widespread FGFR1 positivity was found in the endocervical epithelia. In contrast, immunoreactive FGFR1 was confined to the stratum spinosum, with total sparing of the basal epithelial cell layer in the ectocervix. Widespread immunoreactive FGFR3 was seen in the ecto- and endocervix, stromal fibroblasts, and the tissue vasculature, in contrast to the lack of FGFR2 and FGFR4 positivity in the cervix. Similarly, wide expression of FGFR1 and FGFR3 was seen in placental chorionic villi, with no FGFR2 or FGFR4 expression at this site. High levels of FGFR2 were found in the ducts, stromal fibroblasts, and vasculature of the breast (Figure 5), with little FGFR1 and FGFR3 expression and total lack of FGFR4.
Conversely, tissues constituting the male reproductive tract showed only weak positivity for FGFRs. The only tissue to exhibit wide expression was the prostate gland. In this tissue, FGFR1 and FGFR2 expression was seen in prostate epithelium and the microvasculature. In the epididymis, testis, and vas deferens there was little FGFR expression, and this was essentially confined to the media of small blood vessels and the muscularis of the vas deferens.
Heart and Respiratory System
Expression of FGFR1 and FGFR4 was especially marked in cardiac myocytes, with barely detectable staining for the other receptors. In the respiratory system, the distribution of FGFR2 was more widespread than that of the other three receptors. Intense FGFR2 positivity was detected in the respiratory epithelium, chondrocytes, muscularis, and vasculature, although FGFR2 was absent from the alveoli. In contrast, FGFR1 immunoreactivity was seen in the basal layer of respiratory epithelial cells and in many microvessels, with weak staining of chondrocytes and monocytes. Overall, there was limited expression of FGFR3 and FGFR4 in respiratory tissues. However, immunoreactive FGFR4 was seen in the smooth muscle cells underlying the bronchi and bronchioles.
Endocrine Tissues
Compared with all other tissues analyzed, the most widespread and greatest degree of immunoreactivity for all four receptors was observed in endocrine tissues. Staining for FGFRs was also frequently observed in cells of the same type. Intense immunoreactive FGFR1 and FGFR2 were seen focally in discrete populations of basophils and acidophils located at the periphery of the pituitary gland (Figure 6A). In contrast, low levels of FGFR3 and no expression of FGFR4 were seen in these cells. In general, widespread expression of FGFR family members was seen in the parathyroid gland and adrenal cortex, although immunoreactive FGFR4 was absent from the former tissue. The steroidogenic cells of the adrenal cortex and the oxyphilic and chief cells of the parathyroid gland showed intense positivity for FGFR1 (Figure 6B), FGFR2, and FGFR3, as did the tissue vasculature. In the thyroid gland, FGFR2 was seen focally in follicular epithelial cells, and expression of FGFR1 and FGFR3 was confined to the vasculature.
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Gastrointestinal System
Immunostaining with the anti-human FGFR1-4 antibodies revealed an unusual pattern of staining in the gastrointestinal tract. FGFR1 was not observed in the epithelium or vasculature of the stomach, and extremely faint staining of the muscularis was seen. A similar lack of expression in this tissue was observed for FGFR3. In contrast, marked expression of FGFR4 was seen predominantly in the muscularis, and expression of FGFR2 was seen throughout the gastric epithelium and submucosal macro- and microvasculature, with marked expression in the muscularis mucosae and muscularis. In the duodenum, positivity for FGFR1 was seen in the epithelial cells at the tips of villi. The muscularis mucosae, muscularis, and vessels of the submucosa were essentially nonreactive. Foci of FGFR1-positive microvessels in association with the outer layer of the muscularis were seen. For FGFR4, moderate focal immunoreactivity was detected in the muscularis but there was total lack of expression in the muscularis mucosae, lamina propria, and mucosa. The media of a few submucosal arterioles and veins demonstrated FGFR4 immunoreactivity, as well as the occasional capillary. In contrast, the FGFR1-positive microvessels associated with the muscularis were nonreactive for this receptor despite moderate FGFR4 positivity in microvessels at other sites. There was little expression of FGFR3 in this tissue.
Patterns of FGFR3 and FGFR1 expression in both the ileum and appendix were remarkably similar, with positivity seen primarily in the epithelia at the tips of villi. FGFR4 expression was not observed in the appendix, and faint focal staining of the muscularis of the ileum was seen. In these tissues, FGFR2 expression was more widespread than that observed for the other receptors, and the entire mucosal epithelium and muscularis of the appendix exhibited marked positivity, as did the ileal submucosal vasculature and muscularis mucosae. High levels of FGFR1 were seen in the colon, where there was marked positivity throughout the epithelium lining colonic glands, fibroblasts of the lamina propria, muscularis mucosae, and vessels of the submucosa and microvessels. A similar pattern of expression was seen for FGFR3 and FGFR2. Notably, the epithelial cells at the crypt luminal surface were nonreactive for FGFR3. Little staining for FGFR4 was seen in this tissue, although focal areas of positive smooth muscle cells in the muscularis were noted.
A striking differential pattern of FGFR expression was observed in the pancreas. There was intense positivity for FGFR3 in the islets of Langerhans (Figure 7A). Small foci of FGFR4-positive cells were also seen in the islets, but there was total lack of FGFR2 (Figure 7B) and FGFR1 reactivity at this site. Similarly, in the vasculature of this organ, the media of small arterioles and veins showed variable levels of FGFR1 and FGFR3 expression. In contrast, FGFR4 was seen predominantly in the media of arterioles, with absence of staining in the media of adjacent veins. This unusual differential pattern of FGFR4 expression in the vasculature was not apparent in other tissues examined, in which medial smooth muscle cells of both veins and arterioles tended to show positivity.
In the liver, differential patterns of FGFR expression were observed. Marked levels of expression of FGFR1, FGFR3, and FGFR4 were seen in this tissue, with variable degrees of immunostaining for all three receptors in the hepatocytes and portal tract vasculature. In addition, expression of FGFR1, FGFR3, and FGFR4 was seen in bile duct epithelium. In contrast, minimal FGFR2 expression was observed in hepatocytes and bile duct epithelium, but there was strong staining of medial smooth muscle cells of the portal tract vasculature. There was total absence of staining for all four receptors in the fibroblasts of the portal tracts.
The submandibular and sublingual salivary glands provided further examples of distinct differences in the spatial patterns of FGFR expression. In the sublingual gland, high levels of FGFR3 expression were seen in the glandular epithelium and moderate levels in the tissue vasculature (Figure 8A). The ducts of the sublingual gland were nonreactive for FGFR3, but expression of FGFR1 (Figure 8B), FGFR2, and FGFR4 was seen at this site. There was marked deviation in the submandibular gland, where FGFR3 was detected primarily in the ducts but not in the glandular epithelium. For FGFR1 and FGFR2, the patterns of expression seen in the sublingual gland were essentially maintained in the submandibular gland. No expression of FGFR1-4 was seen in connective tissue fibroblasts of either type of salivary gland.
Lymphoid Tissues
In the thymus, intense FGFR1 positivity was seen in epithelial cells, Hassl's corpuscles, and the endothelium and smooth muscle cells of blood vessels. Expression of FGFR2, FGFR3, and FGFR4 was seen predominantly in the thymic vasculature. In the lymph node and tonsil, intense expression of FGFR1 and FGFR2 was noted in high endothelial venules and in the media of all arterioles and venules. FGFR3 and FGFR4 expression was not observed in the high endothelial venules, and FGFR3 was absent from vessels in the lymph node itself, whereas the media of small blood vessels in the lymph node showed marked FGFR4 positivity. Similarly, the media of the muscular artery included in this section showed moderate expression of FGFR4, but the medial smooth muscle cells of neighboring veins showed intense immunoreactivity for this receptor. The pattern of FGFR expression described in the vasculature of the lymph node and attached connective tissue is not unique. Highly variable and complex patterns of receptor expression in the vasculature were a common feature for most tissues examined in this study.
Other Tissues
In addition to reviewing the major organ systems, the cornea and sympathetic ganglia were also examined. The anti-human FGFR1-4 antisera revealed a widespread and subtle differential distribution of the FGFRs in the cornea. For example, immunoreactive FGFR3 was found throughout the cornea, and intense positivity was seen in the corneal epithelium, endothelium, Descemet's membrane, and fibroblasts of the substantia propria. In contrast, expression of FGFR1 and FGFR4 was confined to corneal epithelial and endothelial cells, with lack of immunoreactivity in fibroblasts. FGFR2 was entirely absent in this tissue. In sympathetic ganglia, intense immunoreactive FGFR1 and FGFR3 were detected in Schwann cells, but not FGFR4 or FGFR2. Heterogeneous expression of FGFR1, FGFR2, and FGFR3 was seen in the associated vasculature, but not FGFR4.
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Discussion |
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The present study describes the tissue-specific cell localization of the FGFR multigene family in a panel of normal human adult tissues using a sensitive immunohistochemical technique and specific polyclonal FGFR1-4 antisera. The results obtained show the widespread spatial distribution of FGFR1-4 in tissues from the major organ systems and striking differential FGFR expression in multiple tissues. These data show good correlation with previous immunolocalization studies documenting the wide expression of the ligands for these receptors, FGF-1 and FGF-2, in the same panel of tissues (
Similarly, comparison of these results with patterns of FGFR expression in other species reveals further variation. For example, the extensive studies of
There are many possible reasons for the conflicting reports in FGFR1-4 tissue distribution. Evidence suggests that temporal differences in receptor expression exist between adult and fetal tissues. Indeed, caution must be exercised in extrapolating results obtained in the fetus to those seen in the adult, in view of such differences. Species-specific variations may also occur. Technical variation may also be partly responsible. For example, the decreased sensitivity of Northern blotting may give rise to misleadingly low or lack of receptor expression. Similarly, a panoply of different molecular probes has been employed to detect FGFR gene expression. Furthermore, the cellular expression of FGFR mRNA transcripts does not necessarily correlate with the expression of protein at the cell surface (
The cell type-specific alternate processing of FGFR1 and FGFR2 mRNA transcripts by different tissues provides yet another potential explanation. Tissue- and cell type-specific variations in patterns of FGFR1 and FGFR2 splice variant expression are well-documented (
Further evidence to reinforce this notion is provided by an earlier analysis of the tissue distribution of human FGFR1 utilizing a polyclonal antibody directed against the acidic region of the chicken basic FGF receptor (cek-1 gene product), the chicken homologue of human FGFR1 (
FGFR1, FGFR2, and FGFR3 were widely expressed in many adult human tissues. These receptors bind FGF-1 and FGF-2 with high affinity (
FGF-1 and FGF-2 and their cognate receptors have been implicated in a wide range of normal physiological processes in vivo and in various disease states, including certain forms of neoplasia, atherosclerosis, diabetic retinopathy, and neurodegenerative disorders (
In conclusion, the present results indicate that expression of the FGFRs is regulated spatially in a cell type- and tissue-specific manner in the adult. This phenomenon is a common theme for FGFR family members during the development of various species. The functional significance of these highly complex differential patterns of receptor expression in adult tissues under normal physiological conditions in vivo remains speculative, although such differences probably serve to create functional diversity. This interpretation is consistent with the multifunctional nature of FGF ligands that induce diverse cellular responses in multiple cell types (e.g., proliferation, differentiation, chemotaxis) and the overlapping ligand-binding specificities exhibited by FGFRs and their isoforms. At the cellular level, variations in FGFR expression may in turn lead to functional differences essential for the coordinate regulation of normal tissue homeostasis and the orchestration of complex processes, such as wound healing and tissue repair, that involve more than one cell type and demand a repertoire of biological responses from individual cells. Moreover, the aberrant or inappropriate expression of FGFRs in normal human adult tissues, coupled with abundant FGF-1 and FGF-2 in tissues of endodermal, neuroectodermal, and mesenchymal origin may play a critical role in the development and/or progression of a wide range of tumors. Indeed, there is growing evidence implicating the FGF-FGFR multigene families in the pathogenesis of carcinoma of the colon (
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Acknowledgments |
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Supported by grants from the British Heart Foundation and the Special Trustees for St Thomas's Hospital.
Received for publication October 7, 1996; accepted February 6, 1997.
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Literature Cited |
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Abraham JA, Whang JL, Tumolo A, Mergia A, Friedman J, Gospodarowicz D, Fiddes JC (1986) Human basic fibroblast growth factor: nucleotide sequence and genomic organization. EMBO J 5:2523-2528[Abstract]
Armstrong E, Vainikka S, Partanen J, Korhonen J, Alitalo R (1992) Expression of fibroblast growth factor receptors in human leukemia cells. Cancer Res 52:2004-2007[Abstract]
Baird A, Bohlen P (1990) Fibroblast growth factors. In Sporn MB, Roberts AB, eds. Handbook of Experimental Pharmacology: Peptide Growth Factors and their Receptors. Berlin, Springer-Verlag, 369-418
Barritault D, Groux-Muscatelli B, Caruelle D, Voisin M-C, Chopin D, Palcy S, Caruelle JP (1991) Acidic fibroblast growth factor content increases with malignancy in human chondrosarcoma and bladder cancer. Ann NY Acad Sci 638:387-393[Medline]
Basilico C, Moscatelli D (1992) The FGF family of growth factors and oncogenes. Adv Cancer Res 59:115-165[Medline]
Becker D, Lee PL, Rodeck U, Herlyn M (1992) Inhibition of the fibroblast growth factor receptor 1 (FGFR-1) gene in human melanocytes and malignant melanomas leads to inhibition of proliferation and signs indicative of differentiation. Oncogene 7:2303-2313[Medline]
Bellot F, Crumley G, Kaplow JM, Schlessinger J, Jaye M, Dionne CA (1991) Ligand-induced transphosphorylation between different FGF receptors. EMBO J 10:2849-2854[Abstract]
Bernard O, Li M, Reid HH (1991) Expression of two different forms of fibroblast growth factor receptor 1 in different mouse tissues and cell lines. Proc Natl Acad Sci USA 88:7625-7629[Abstract]
Brem S, Tsanaclis AMC, Gately S, Gross JL, Herblin WF (1992) Immunolocalization of basic fibroblast growth factor to the microvasculature of human brain tumours. Cancer 70:2673-2680[Medline]
Champion-Arnaud P, Ronsin C, Gilbert E, Gesnel MC, Houssaint E, Breathnach R (1991) Multiple mRNAs code for proteins related to the BEK fibroblast growth factor receptor. Oncogene 6:979-987[Medline]
Chodak GW, Hospelhorn V, Judge SM, Mayforth R, Koeppen H, Sasse J (1988) Increased levels of fibroblast growth factor-like activity in urine from patients with bladder or kidney cancer. Cancer Res 48:2083-2088[Abstract]
Cordon-Cardo C, Vlodavsky I, Haimovitz-Friedman A, Hicklin D, Fuks Z (1990) Expression of basic fibroblast growth factor in normal human tissues. Lab Invest 63:832-840[Medline]
Crumley G, Bellot F, Kaplow JM, Schlessinger J, Jaye M, Dionne CA (1991) High-affinity binding and activation of a truncated FGF receptor by both aFGF and bFGF. Oncogene 6:2255-2262[Medline]
DeLapeyriere O, Rosnet O, Benharroch F, Raybaud S, Marchetto J, Planche F, Galland F, Mattei M-G, Copeland NG, Jenkins NA, Coulier F, Birnbaum D (1990) Structure, chromosome mapping and expression of the murine FGF-6 gene. Oncogene 5:823-831[Medline]
Dionne CA, Crumley G, Bellot F, Kaplow JM, Searfoss G, Ruta M, Burgess WH, Jaye M, Schlessinger J (1990) Cloning and expression of two distinct high-affinity receptors cross-reacting with acidic and basic fibroblast growth factors. EMBO J 9:2685-2692[Abstract]
Eisemann A, Ahn JA, Graziani G, Tronick SR, Ron D (1991) Alternative splicing generates at least five different isoforms of the human basic-FGF receptor. Oncogene 6:1195-1202[Medline]
Engelmann GL, Dionne CA, Jaye MC (1993) Acidic fibroblast growth factor and heart development. Role in myocyte proliferation and capillary angiogenesis. Circ Res 72:7-19[Abstract]
Finch PW, Rubin JS, Miki T, Ron D, Aaronson SA (1989) Human KGF is FGF-related with properties of a paracrine effector of epithelial cell growth. Science 245:752-755[Medline]
Givol D, Yayon A (1992) Complexity of FGF receptors: genetic basis for structural diversity and functional specificity. FASEB J 6:3362-3369
Hattori Y, Odagiri H, Nakatani H, Miyagawa K, Naito K, Sakamoto H, Katoh O, Yoshida T, Sugimura T, Terada M (1990) K-sam, an amplified gene in stomach cancer, is a member of the heparin-binding growth factor receptor genes. Proc Natl Acad Sci USA 87:5983-5987[Abstract]
Haub O, Goldfarb M (1991) Expression of the fibroblast growth factor-5 gene in the mouse embryo. Development 112:397-406[Abstract]
Hebert J, Basilico C, Goldfarb M, Haub O, Martin GR (1990) Isolation of cDNAs encoding four mouse FGF family members and characterization of their expression patterns during embryogenesis. Dev Biol 138:454-463[Medline]
Holtrich U, Brauninger A, Strebhardt K, Rubsamen-Waigmann H (1991) Two additional protein-tyrosine kinases expressed in human lung: fourth member of the fibroblast growth factor receptor family and an intracellular protein-tyrosine kinase. Proc Natl Acad Sci USA 88:10411-10415[Abstract]
Hou J, Kan M, McKeehan K, McBride G, Adams P, McKeehan WL (1991) Fibroblast growth factor receptors from liver vary in three structural domains. Science 251:665-668[Medline]
Hughes SE, Hall PA (1993a) Immunolocalization of fibroblast growth factor receptor 1 and its ligands in human tissues. Lab Invest 71:173-182
Hughes SE, Hall PA (1993b) Editorialthe fibroblast growth factor and receptor multigene families. J Pathol 170:219-221[Medline]
Hughes SE, Hobbs C, Hall PA (1994) Expression of the fibroblast growth factor receptor (FGFR) multigene family in normal and atherosclerotic human arteries. J Pathol 172:1-49[Medline]
Jakobovits A, Shackleford G, Varmus H, Martin G (1986) Two proto-oncogenes implicated in mammary carcinogenesis, int-1 and int-2, are independently regulated during mouse development. Proc Natl Acad Sci USA 83:7806-7810[Abstract]
Jaye M, Howk R, Burgess W, Ricca GA, Chiu IM, Ravera MW, O'Brien SJ, Modi WS, Maciag T, Drohan WN (1986) Human endothelial cell growth factor: cloning nucleotide sequence, and chromosome localization. Science 233:541-545[Medline]
Katoh M, Hattori Y, Sasaki H, Tanaka M, Sugano K, Yazaki Y, Sugimura T, Terada M (1992) K-sam gene encodes secreted as well as transmembrane receptor tyrosine kinase. Proc Natl Acad Sci USA 89:2960-2964[Abstract]
Keegan K, Johnson DE, Williams LT, Hayman MJ (1991a) Isolation of an additional member of the fibroblast growth factor receptor family, FGFR-3. Proc Natl Acad Sci USA 88:1095-1099[Abstract]
Keegan K, Johnson DE, Williams LT, Hayman MJ (1991c) Characterization of the FGFR-3 gene and its product. Ann NY Acad Sci 638:400-402[Medline]
Keegan K, Meyer S, Hayman MJ (1991b) Structural and biosynthetic characterization of the fibroblast growth factor receptor 3 (FGFR-3) protein. Oncogene 6:2229-2236[Medline]
Korhonen J, Partanen J, Eerola E, Vainikka S, Ilvesmaki V, Voutilainen Julkunen M, Makela T, Alitalo K (1991) Novel human FGF receptors with distinct expression patterns. Ann NY Acad Sci 638:403-405[Medline]
Kornbluth S, Paulson KE, Hanafusa H (1988) Novel tyrosine kinase identified by phosphotyrosine antibody screening of cDNA libraries. Mol Cell Biol 8:5541-5544[Medline]
Luqmani YA, Graham M, Coombes RC (1992) Expression of basic fibroblast growth factor, FGFR1 and FGFR2 in normal and malignant human breast, and comparison with other normal tissues. Br J Cancer 66:273-280[Medline]
Mignatti P, Morimoto T, Rifkin DB (1992) Basic fibroblast growth factor, a protein devoid of secretory signal sequence, is released by cells via a pathway independent of the endoplasmic reticulum-Golgi complex. J Cell Physiol 151:81-93[Medline]
Miki T, Bottaro DP, Fleming TP, Smith CL, Burgess WH, Chan A, Aaronson SA (1992) Determination of ligand-binding specificity by alternative splicing: two distinct growth factor receptors encoded by a single gene. Proc Natl Acad Sci USA 89:246-250[Abstract]
New BA, Yeoman LC (1992) Identification of basic fibroblast growth factor sensitivity and receptor and ligand expression in human colon tumor cell lines. J Cell Physiol 150:320-326[Medline]
Orr-Urtreger A, Givol D, Yayon A, Yarden Y, Lonai P (1991) Developmental expression of two murine fibroblast growth factor receptors, flg and bek. Development 113:1419-1434[Abstract]
Partanen J, Makela TP, Alitalo R, Lehvaslaiho H, Alitalo K (1990) Putative tyrosine kinases expressed in K-562 human leukemia cells. Proc Natl Acad Sci USA 87:8913-8917[Abstract]
Partanen J, Makela TP, Eerola E, Korhonen H, Hirvonen H, Claesson-Welsh L, Alitalo K (1991) FGFR-4, a novel acidic fibroblast growth factor receptor with a distinct expression pattern. EMBO J 10:1347-1354[Abstract]
Patstone G, Pasquale EB, Maher PA (1993) Different members of the fibroblast growth factor receptor family are specific to distinct cell types in the developing chick embryo. Development 155:107-123
Peters KG, Werner S, Chen G, Williams LT (1992) Two FGF receptor genes are differentially expressed in epithelial and mesenchymal tissues during limb formation and organogenesis in the mouse. Development 114:233-243[Abstract]
Reid HH, Wilks AF, Bernard O (1990) Two forms of the basic fibroblast growth factor receptor-like mRNA are expressed in the developing mouse brain. Proc Natl Acad Sci USA 87:1596-1600[Abstract]
Safran A, Avivi A, Orr-Urtereger A, Neufeld G, Lonai P, Givol D, Yarden Y (1990) The murine flg gene encodes a receptor for fibroblast growth factor. Oncogene 5:635-643[Medline]
Schlessinger J, Ullrich A (1992) Growth factor signalling by receptor tyrosine kinases. Neuron 9:383-391[Medline]
Shi E, Kan M, Xu J, Wang F, Hou J, McKeehan WL (1993) Control of fibroblast growth factor receptor kinase signal transduction by heterodimerization of combinatorial splice variants. Mol Cell Biol 13:3907-3917[Abstract]
Stark KL, McMahon JA, McMahon AP (1991) FGFR-4, a new member of the fibroblast growth factor receptor family, expressed in the definitive endoderm and skeletal muscle lineages of the mouse. Development 113:641-651[Abstract]
Takahashi K, Sawasaki Y, Hata J-I, Mukai K, Goto T (1990) Spontaneous transformation and immortalization of human endothelial cells. In Vitro Cell Dev Biol 25:265-274
Takahashi JA, Suzui H, Yasuda Y, Ito N, Ohta M, Jaye M, Fukumoto M, Oda Y, Kikuchi H, Hatanaka M (1991) Gene expression of fibroblast growth factor receptors in the tissues of human gliomas and meningiomas. Biochem Biophys Res Commun 177:1-7[Medline]
Templeton TJ, Hauschka SD (1992) FGF-mediated aspects of skeletal muscle growth and differentiation are controlled by a high affinity receptor, FGFR1. Dev Biol 154:169-181[Medline]
Vainikka S, Partanen J, Bellosta P, Coulier F, Basilico C, Jaye M, Alitalo K (1992) Fibroblast growth factor receptor-4 shows novel features in genomic structure, ligand binding and signal transduction. EMBO J 11:4273-4280[Abstract]
Wanaka A, Milbrandt J, Johnson EM, Jr (1990) Localization of FGF receptor mRNA in the adult rat central nervous system by in situ hybridization. Neuron 5:267-281[Medline]
Wanaka A, Milbrandt J, Johnson EM, Jr (1991) Expression of FGF receptor gene in rat development. Development 111:455-468[Abstract]
Werner S, Duan D-S, de Vries C, Peters KG, Johnson DE, Williams LT (1992) Differential splicing in the extracellular region of fibroblast growth factor receptor 1 generates receptor variants with different ligand-binding specificities. Mol Cell Biol 12:82-88[Abstract]
Wilkinson D, Bhatt S, McMahon A (1989) Expression pattern of the FGF-related proto-oncogene int-2 suggests multiple roles in fetal development. Development 105:131-136[Abstract]
Yan G, Fukabori Y, McBride G, Nikolaropolous S, McKeehan WL (1993) Exon switching and activation of stromal and embryonic fibroblast growth factor (FGF)-FGF receptor genes in prostate epithelial cells accompany stromal independence and malignancy. Mol Cell Biol 13:4513-4522[Abstract]
Yan G, Wang F, Fukabori Y, Sussman D, Hou J, McKeehan WL (1992) Expression and transformation of a variant of the heparin-binding fibroblast growth factor receptor (flg) gene resulting from splicing of the exon at alternate 3'-acceptor site. Biochem Biophys Res Commun 183:423-430[Medline]
Yoshida T, Tsutsumi H, Sakamoto K, Miyagawa S, Teshima S, Sugimura T, Terada M (1988) Expression of the HST1 oncogene in human germ cell tumors. Biochem Biophys Res Commun 155:1324-1329[Medline]