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Query: EC:2.7.10.1 (
ERK
)
95,504
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
A primary culture system of olfactory cells derived from newborn mouse was established by coculturing with a feeder layer of brain astrocytes. In this system, the whole lifespan of olfactory cells could be observed in vitro. Neurogenesis occurred from 5 days after plating and coexistence of immature and mature olfactory cells was observed until day 14. After day 15, immature cells were diminished and most of the culture cells appeared differentiated after day 20. The lifespan of differentiated cells was estimated to be 3 to 6 weeks. Cultured cells expressed growth associated protein 43 (GAP43), neurofilament protein (NFP), protein gene product 9.5 (PGP9.5) and olfactory marker protein (OMP). In addition, other round cells were cytokeratin-positive by immunostaining. RT-PCR of growth factor receptors on the coculture cells revealed the expressions of fibroblast growth factor receptor 2 (FGFR2) and
FGFR3
, both of which could not be detected in the feeder cell layer of astrocytes.
FGFR1
and transforming growth factor beta receptor (TGF beta R) were detected both on the coculture and on feeder cells.
FGFR4
, insulin-like growth factor 2 receptor (IGF2R) and hepatocyte growth factor receptor (HGFR) could not be detected in both samples. Furthermore, basic
FGF
, a prototypic
FGF
, was also found in the coculture system and in feeder cells. The present study indicated
FGF
might affect regulation of proliferation and differentiation of olfactory cells.
...
PMID:[Proliferation and differentiation of olfactory cells in primary culture system]. 910 46
The c-ret proto-oncogene encodes a receptor tyrosine kinase which plays an important role in kidney and enteric nervous system development. Germline mutations in c-ret are responsible for the dominantly inherited cancer syndromes, multiple endocrine neoplasia types 2A and 2B and familial medullary thyroid carcinoma as well as the developmental disorder Hirschsprung's disease. Using SK-N-MC neuroepithelioma cells stably transfected with an
EGFR
/Ret chimeric receptor, we have studied cellular consequences and signalling events following activation of exogenous
EGFR
/Ret and endogenous
FGF
and PDGF receptor tyrosine kinases in cells of neuroectodermal origin. Here we report that Ret activation led to cell scattering, growth inhibition and loss of anchorage-independent growth. Basic
FGF
, but not PDGF, evoked similar responses in those cells. Nevertheless, activation of all three receptor tyrosine kinases led to ERK2 activation. Analysis of the kinetics of ERK2 activation and downstream events revealed that Ret and FGF receptor activation led to sustained ERK2 activation and SRE transactivation, while PDGF treatment led to transient ERK2 activation and failed to induce SRE transactivation. Our results suggest that sustained, but not transient ERK2 activation may be involved in cell scattering.
...
PMID:Cell scattering of SK-N-MC neuroepithelioma cells in response to Ret and FGF receptor tyrosine kinase activation is correlated with sustained ERK2 activation. 912 63
Studies on epidermal-growth-factor-like-, fibroblast- and transforming growth factors suggested their implication in tumorigenesis involving effects on tumour-cell proliferation and migration. In human transitional-cell carcinomas (TCC), enhanced expression of TGF alpha and EGF receptors correlated with an aggressive phenotype. However, little is known about functions of these growth factors in invasive TCCs. In this study, we performed protein- and RNA-expression studies on a set of growth factors and their receptors on the newly established invasive human TCC cell line designated 1207. The data were correlated with functional proliferation and migration studies. Similar expression patterns of many cellular markers, growth factors and their receptors were noted both in the original TCC tissue and in its derivative cell line, indicating the relevance of this cell line to the investigation of growth factor functions on TCC cells. The proliferation induction by EGF, TGF alpha, amphiregulin, heregulin alpha,
FGF
-1 and FGF-7 correlated with the presence of EGF receptors, c-erbB4 and
FGFR2
(IIIb), respectively. Amphiregulin and heregulin alpha induced the most proliferation. In conformity with the low expression of TGF beta receptors I and II, TGF beta1, barely inhibited proliferation, while TGF alpha induced invasion of 1207 cells into Matrigel. These data support the notion that notably EGF-like proteins mediate TCC growth and invasion through autocrine pathways which can be reinforced by loss of TGF beta1 regulation.
...
PMID:Expression and functions of EGF, FGF and TGFbeta-growth-factor family members and their receptors in invasive human transitional-cell-carcinoma cells. 913 55
In this study we describe the presence of high affinity FGF-2 binding sites in the nuclei of U251MG glioma cells (K(d)=7 pM). Immunoprecipitation of total cell extracts with FGF receptor (FGFR) 1-4 antibodies showed that U251MG glioma cells express only
FGFR1
. [125I]FGF-2 cross linking to nuclear extracts followed by
FGFR1
immunoprecipitation showed that
FGFR1
may account for the nuclear FGF-2 binding sites. Western blot analysis demonstrated the presence of 103, 118 kDa and small amounts of 145 kDa
FGFR1
isoforms in the nuclei of glioma cells. All isoforms contain both the C- and N-terminal domains. Nuclear
FGFR1
retains kinase activity. Immunocytochemistry using confocal microscopy showed specific
FGFR1
immunoreactivity within the nuclear interior. In continuously proliferating glioma cells, nuclear
FGFR1
is constitutively expressed, independent of cell density. In contrast, in nontransformed human astrocytes, nuclear
FGFR1
levels fluctuate with the proliferative state of the cell. In quiescent, confluent astrocytes nuclear FGFR1 protein was depleted. An accumulation of nuclear
FGFR1
was observed following the transition to a subconfluent, proliferating state. Transfection of a pcDNA3.1-
FGFR1
expression vector into glioma cells that do not express
FGFR1
resulted in the nuclear accumulation of
FGFR1
, increased cell proliferation, and stimulated transition from the G0/G1 to the S-phase of the cell cycle. The increased proliferative rate was resistant to inhibition by the cell-impermeable
FGF
binding antagonist, myoinositol hexakis [dihydrogen phosphate]. Our results suggest that the constitutive nuclear presence of
FGFR1
contributes to the increased proliferation of glioma cells while the transient nuclear accumulation of
FGFR1
in normal astrocytes may play a role in the transition to a reactive state.
...
PMID:Nuclear accumulation of fibroblast growth factor receptors in human glial cells--association with cell proliferation. 917 56
Acidic fibroblast growth factor (FGF1) and two of its receptors,
FGFR1
and
FGFR4
, were localized in cryostat sections of normal, benign and malignant human breast tissue by immunohistochemistry. Without pretreatment, FGF1 staining was mainly seen in normal epithelial cells. However, polymerase chain reaction (PCR) analysis and immunoblotting of isolated normal epithelial and myoepithelial cells showed FGF1 mRNA and protein to be present in both cell types. Following incubation of frozen sections at 37 degrees C in phosphate-buffered saline, FGF1 staining was also revealed in myoepithelial cells and basement membrane adjacent to carcinoma cells. Treatment with protease inhibitors demonstrated that this effect was due to the activity of an endogenous protease. In contrast, FGF1 staining was found to be associated with the stroma adjacent to malignant cells only in the presence of protease inhibitors.
FGFR1
and
FGFR4
immunostaining was localized to both normal and malignant epithelial cells and to a lesser extent to myoepithelial cells. There was no difference in the staining intensity for the
FGF
receptors between normal and cancer samples. The change in location of FGF1 between normal and malignant tissues and the sensitivity of stored FGF1 to the action of endogenous proteases raises the possibility of both autocrine and paracrine roles for FGF1 in the normal and malignant human breast.
...
PMID:The location of acidic fibroblast growth factor in the breast is dependent on the activity of proteases present in breast cancer tissue. 918 78
Adherent cultures of E10.5 rat neuroepithelial cells (
NEP
cells) from the caudal neural tube require
FGF
(fibroblast growth factor) and CEE (chick embryo extract) to proliferate and maintain an undifferentiated phenotype in culture. Epidermal growth factor (EGF) does not support E10.5
NEP
cells in adherent culture and
NEP
cells do not form EGF-dependent neurospheres.
NEP
cells, however, can be grown as
FGF
-dependent neurospheres.
NEP
cells express nestin and lack all lineage-specific markers for neuronal and glial sublineages, retain their pleuripotent character over multiple passages, and can differentiate into neurons, astrocytes, and oligodendrocytes when plated on laminin in the absence of CEE. In clonal culture,
NEP
cells undergo self-renewal and generate colonies that vary in size from single cells to several thousand cells. With the exception of a few single-cell clones, all other
NEP
-derived clones contain more than one identified phenotype, with over 40% of the colonies containing A2B5, beta-111 tubulin, and GFAP-immunoreactive cells. Thus,
NEP
cells are multipotent and capable of generating multiple neural derivatives.
NEP
cells also differentiate into motoneurons immunoreactive for choline acetyl transferase (ChAT) and the low-affinity neurotrophin receptor (p75) in both mass and clonal culture. Double labeling of clones for ChAT and glial, neuronal, or oligodendrocytic lineage markers shows that motoneurons always arose in mixed cultures with other differentiated cells. Thus,
NEP
cells represent a common progenitor for motoneurons and other spinal cord cells. The relationship of
NEP
cells with other neural stem cells is discussed.
...
PMID:Neuroepithelial stem cells from the embryonic spinal cord: isolation, characterization, and clonal analysis. 920 40
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 wide-spread 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 wide-spread 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.
...
PMID:Differential expression of the fibroblast growth factor receptor (FGFR) multigene family in normal human adult tissues. 921 26
We isolated a novel bHLH protein gene Mesp2 (for mesoderm posterior 2) that cross-hybridizes with Mesp1 expressed in the early mouse mesoderm. Mesp2 is expressed in the rostral presomitic mesoderm, but down-regulated immediately after the formation of the segmented somites. To determine the function of MesP2 protein (MesP2) in somitogenesis, we generated Mesp2-deficient mice by gene targeting. The homozygous Mesp2 (-/-) mice died shortly after birth and had fused vertebral columns and dorsal root ganglia, with impaired sclerotomal polarity. The earliest defect in the homozygous embryos was a lack of segmented somites. Their disruption of the metameric features, altered expression of Mox-1, Pax-1, and Dll1, and lack of expression of Notch1, Notch2, and
FGFR1
suggested that MesP2 controls sclerotomal polarity by regulating the signaling systems mediated by notch-delta and
FGF
, which are essential for segmentation.
...
PMID:Mesp2: a novel mouse gene expressed in the presegmented mesoderm and essential for segmentation initiation. 924 90
FGF
ligands and FGF receptor 1 (FGFR1) appear associated with the nucleus in addition to their extracellular and transmembrane locations. After receptor-dependent internalization in liver cells, radiolabeled 16-kDa
FGF
-1 appears in a 40-kDa covalent complex with a cellular protein. In this report, we show that in a human hepatoma cell line, HepG2, which expresses both
FGFR4
and FGFR1, the 40-kDa complex cross-reacts with antibodies against the ectodomain of both types of receptors. In addition to antibody against
FGF
-1, a polyclonal antiserum against the three immunoglobulin (Ig)-like loop ectodomain of
FGFR4
and a monoclonal antibody to a 19-residue sequence in the NH2-terminus of the NH2-terminal Ig Loop I of the three loop splice variant of FGFR1 (FGFR1alpha) reacts with the complex. A monoclonal antibody against an epitope in FGFR1 downstream of the inter-loop I/II sequence which reacts with intact FGFR1 failed to cross-react with the 40-kDa complex. Cell fractionations and indirect immunofluorescent localization revealed that the 40-kDa complex associates with the particulate fraction of cells, particularly the nucleus and associated cytoskeletal elements. We propose that the NH2-terminal Ig-loop of the three loop isoforms of FGFR, which are generally associated inversely with cell growth, may play a role at or in the nucleus in addition to modification of affinity of the FGFR ectodomain for heparan sulfate and
FGF
ligand.
...
PMID:Nuclear localization of a complex of fibroblast growth factor(FGF)-1 and an NH2-terminal fragment of FGF receptor isoforms R4 and R1alpha in human liver cells. 924 77
Fibroblast growth factor 2 (FGF2), also known as basic fibroblast growth factor (bFGF), belongs to the
FGF
family, which consists of at least 9 closely related members. FGF2 is a potent mitogen for fibroblasts derived from normal prostate and, to a lesser extent, for prostatic epithelial cells. Its role in the physiology of the normal prostate seems to be limited to stromal cells, whereas in prostate cancer FGF2 may also have an autocrine/paracrine effect on epithelial cells. In order to better understand the effects of FGF2 on the prostatic epithelium, especially its role in the progression of prostate cancer by establishing an autocrine-stimulation loop, we transfected FGF2 cDNA into a human prostatic epithelial cell line, PNT1A, immortalized with SV40 large-T antigen. This cell line is non-tumorigenic and expresses a high-affinity FGF2 receptor,
FGFR1
/flg. We characterized 3 independent FGF2-transfected clones and found that the establishment of an FGF2 autocrine loop on these cells led to (i) serum-independent growth, (ii) increased proliferation and (iii) anchorage-independent growth. Such results argue in favor of the possible action of FGF2 on progression of prostate cancer via an FGF2 autocrine loop on epithelial cells.
...
PMID:Constitutive expression of FGF2/bFGF in non-tumorigenic human prostatic epithelial cells results in the acquisition of a partial neoplastic phenotype. 924 2
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