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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)
The epidermal growth factor (EGF) family and the EGF receptor (
EGFR
, ErbB) tyrosine kinase family have been spearheading the studies of signal transduction events that determine cell fate and behavior in vitro and in vivo. The
EGFR
family and their signaling pathways are giving us tremendous advantages in developing fascinating molecular target strategies for cancer therapy. Currently, two important types of
EGFR
inhibitors are in clinical use: neutralizing antibodies of
EGFR
or ErbB2, and synthetic small compounds of tyrosine kinase inhibitors designed for receptors. On the other hand, basic research of the EGF family ligands presents new challenges as membrane-anchored growth factors. All members of the EGF family have important roles in development and diseases and are shed from the plasma membrane by metalloproteases. The ectodomain shedding of the ligands has emerged as a critical component in the functional transactivation of EGFRs in interreceptor cross-talk in response to various shedding stimulants such as G-protein coupled receptor agonists, growth factors, cytokines, and various physicochemical stresses. Among the
EGFR
-ligands,
heparin-binding EGF-like growth factor
(
HB-EGF
) is a prominent ligand in our understanding of the pathophysiological roles of ectodomain shedding in cancer, wound healing, cardiac diseases, etc. Here we focus on ectodomain shedding of the EGF family ligands, especially
HB-EGF
by disintegrin and metalloproteases, which are not only key events of receptor cross talk, but also novel intercellular signaling by their carboxy-terminal fragments to regulate gene expression directly.
...
PMID:Membrane-anchored growth factors, the epidermal growth factor family: beyond receptor ligands. 1827 17
Little is understood about the regulation of gene expression in human preimplantation embryos. We set out to examine the expression in human preimplantation embryos of a number of genes known to be critical for early development of the murine embryo. The expression profile of these genes was analysed throughout preimplantation development and in response to growth factor (GF) stimulation. Developmental expression of a number of genes was similar to that seen in murine embryos (OCT3B/4, CDX2, NANOG). However, GATA6 is expressed throughout preimplantation development in the human. Embryos were cultured in IGF-I, leukaemia inhibitory factor (LIF) or
heparin-binding EGF-like growth factor
(
HBEGF
), all of which are known to stimulate the development of human embryos. Our data show that culture in
HBEGF
and LIF appears to facilitate human embryo expression of a number of genes:
ERBB4
(LIF) and LIFR and DSC2 (
HBEGF
) while in the presence of
HBEGF
no blastocysts expressed EOMES and when cultured with LIF only two out of nine blastocysts expressed TBN. These data improve our knowledge of the similarities between human and murine embryos and the influence of GFs on human embryo gene expression. Results from this study will improve the understanding of cell fate decisions in early human embryos, which has important implications for both IVF treatment and the derivation of human embryonic stem cells.
...
PMID:Expression of genes involved in early cell fate decisions in human embryos and their regulation by growth factors. 1841 10
Activation of V(1a) receptor triggers the expression of growth-related immediate-early genes (IEGs), including c-Fos and Egr-1. We found that pre-treatment of rat vascular smooth muscle A-10 cell line with the EGF receptor inhibitor AG1478 or the over-expression of an
EGFR
dominant negative mutant (HEBCD533) blocked the vasopressin-induced expression of IEGs, suggesting that activation of these early genes mediated by V(1a) receptor is via transactivation of the EGF receptor. Importantly, the inhibition of the metalloproteinases, which catalyzed the shedding of the EGF receptor agonist
HB-EGF
, selectively blocked the vasopressin-induced expression c-Fos. On the other hand, the inhibition of c-Src selectively blocked the vasopressin-induced expression of Egr-1. Interestingly, in contrast to the expression of c-Fos, the expression of Egr-1 was mediated via the Ras/MEK/MAPK-dependent signalling pathway. Vasopressin-triggered expression of both genes required the release of intracellular calcium, activation of PKC and beta-arrestin 2. These findings demonstrated that vasopressin up-regulated the expression of c-Fos and Erg-1 via transactivation of two distinct EGF receptor-dependent signalling pathways.
...
PMID:Vasopressin up-regulates the expression of growth-related immediate-early genes via two distinct EGF receptor transactivation pathways. 1857 97
We previously reported that EMD (Enamel Matrix Derivative) induces proliferation of human gingival fibroblasts via activation of Extracellular Regulated Kinase (ERK), and this study assessed the possible mediatory role of
EGFR
(Epidermal Growth Factor Receptor) in this effect. Treatment of gingival fibroblasts with EMD resulted in tyrosine phosphorylation of the
EGFR
, as assessed by immunoblotting and ELISA, while EMD-induced ERK activation and thymidine incorporation were markedly inhibited (approximately 40-50%) by a specific
EGFR
tyrosine kinase inhibitor. Using appropriate inhibitors, we established that EMD-induced
EGFR
activation is largely due to shedding of
HB-EGF
(Heparin-binding EGF) from the cell membrane via a metalloproteinase-mediated process. Finally, the addition of PP1, a Src family inhibitor, abrogated both
EGFR
phosphorylation and ERK activation. Taken together, these results indicate that, at least in human gingival fibroblasts, EMD-induced ERK activation and proliferation are partially due to a Src-dependent, metalloproteinase-mediated transactivation of
EGFR
.
...
PMID:EGFR in Enamel Matrix Derivative-induced gingival fibroblast mitogenesis. 1871 12
A site-directed mutagenesis approach was taken to disrupt each of 3 disulfide bonds within human
HB-EGF
by substituting serine for both cysteine residues that contribute to disulfide bonding. Each
HB-EGF
disulfide analogue (
HB-EGF
-Cys/Ser(108/121),
HB-EGF
-Cys/Ser(116/132), and
HB-EGF
-Cys/Ser(134/143)) was cloned under the regulation of the mouse metallothionein (MT) promoter and stably expressed in mouse fibroblasts.
HB-EGF
immunoreactive proteins with M(r) of 6.5, 21 and 24 kDa were observed from lysates of
HB-EGF
and each
HB-EGF
disulfide analogue.
HB-EGF
immunohistochemical analyses of each
HB-EGF
stable cell line demonstrated ubiquitous protein expression except
HB-EGF
-Cys/Ser(108/121) and
HB-EGF
-Cys/Ser(116/132) stable cell lines which exhibited accumulated expression immediately outside the nucleus. rHB-EGF,
HB-EGF
, and
HB-EGF
(134/143) proteins competed with 125I-EGF in an A431 competitive binding assay, whereas
HB-EGF
-Cys/Ser(108/121) and
HB-EGF
-Cys/Ser(116/132) failed to compete. Each
HB-EGF
disulfide analogue lacked the ability to stimulate tyrosine phosphorylation of the 170 kDa
EGFR
. These results suggest that
HB-EGF
-Cys/Ser(134/143) antagonizes EGFRs.
...
PMID:The significance of disulfide bonding in biological activity of HB-EGF, a mutagenesis approach. 1872 2
The human epidermal growth factor (EGF) receptor (HER) family members cooperate in malignancy. Of this family,
HER2
does not bind growth factors and
HER3
does not encode an active tyrosine kinase. This diversity creates difficulty in creating pan-specific therapeutic HER family inhibitors. We have identified single amino acid changes in epidermal growth factor receptor (EGFR) and
HER3
which create high affinity sequestration of the cognate ligands, and may be used as receptor decoys to downregulate aberrant HER family activity. In silico modeling and high throughput mutagenesis were utilized to identify receptor mutants with very high ligand binding activity. A single mutation (T15S; EGFR subdomain I) enhanced affinity for EGF (two-fold), TGF-alpha (twenty-six-fold), and heparin-binding (HB)-EGF (six-fold). This indicates that T15 is an important, previously undescribed, negative regulatory amino acid for EGFR ligand binding. Another mutation (Y246A; HER 3 subdomain II) enhanced neuregulin (NRG)1-beta binding eight-fold, probably by interfering with subdomain II-IV interactions. Further work revealed that the
HER3
subunit of an EGFR:
HER3
heterodimer suppresses EGFR ligand binding. Optimization required reversing this suppression by mutation of the EGFR tether domain (G564A; subdomain IV). This mutation resulted in enhanced ligand binding (EGF, ten-fold; TGF-alpha, thirty-four-fold;
HB-EGF
, seventeen-fold; NRG1-beta, thirty-one-fold). This increased ligand binding was reflected in improved inhibition of in vitro tumor cell proliferation and tumor suppression in a human non-small cell lung cancer xenograft model. In conclusion, amino acid substitutions were identified in the EGFR and
HER3
ECDs that enhance ligand affinity, potentially enabling a pan-specific therapeutic approach for downregulating the HER family in cancer.
...
PMID:Rational optimization of a bispecific ligand trap targeting EGF receptor family ligands. 1904 33
We previously described a population of regulatory macrophages that produced high levels of IL-10 and low levels of IL-12/23. We now describe and characterize the expression of heparin-binding epidermal growth factor (EGF)-like growth factor (
HB-EGF
) by these macrophages.
HB-EGF
has previously been associated with a number of physiological and pathological conditions, including tumor growth and angiogenesis. The induction of
HB-EGF
in regulatory macrophages is due to new transcription and not to increased mRNA stability. The transcription factor Sp1 is a major factor in
HB-EGF
production, and knockdown of Sp1 substantially diminishes
HB-EGF
production. Sp1 was recruited to three sites within the first 2 kb of the
HB-EGF
promoter following stimulation, and the site located at -83/-54 was required for
HB-EGF
promoter activity. These regions of the promoter become more accessible to endonuclease activity following macrophage activation, and this accessibility was contingent on activation of the MAPK,
ERK
. We show that several experimental manipulations that give rise to regulatory macrophages also result in
HB-EGF
production. These observations indicate that in addition to the secretion of the anti-inflammatory cytokine IL-10, another novel characteristic of regulatory macrophages is the production of angiogenic
HB-EGF
.
...
PMID:The expression of heparin-binding epidermal growth factor-like growth factor by regulatory macrophages. 1920 46
Previously, we showed that ACh-induced proliferation of human colon cancer cells is mediated by transactivation of epidermal growth factor (EGF) receptors (EGFRs). In the present study, we elucidate the molecular mechanism underlying this action. ACh-induced proliferation of H508 colon cancer cells, which express exclusively M3 muscarinic receptors (M3Rs), was attenuated by anti-
EGFR
ligand binding domain antibody, a broad-spectrum matrix metalloproteinase (MMP) inhibitor, anti-MMP7 antibody, a diphtheria toxin analog that blocks release of an
EGFR
ligand [
heparin-binding EGF-like growth factor
(
HBEGF
)], and anti-
HBEGF
antibody. Conditioned media from ACh-treated H508 cells induced proliferation of SNU-C4 colon cancer cells that express
EGFR
but not M3R. These actions were attenuated by an
EGFR
inhibitor and by anti-
EGFR
and anti-
HBEGF
antibodies. In H508, but not SNU-C4, colon cancer cells, ACh caused a striking dose- and time-dependent increase in levels of MMP7 mRNA and MMP7 protein. Similarly, ACh induced robust MMP1 and MMP10 gene transcription. ACh-induced MMP1, MMP7, and MMP10 gene transcription was attenuated by atropine, anti-
EGFR
antibody, and chemical inhibitors of
EGFR
and
ERK
activation. In contrast, inhibitors of phosphatidylinositol 3-kinase and NF-kappaB activation did not alter MMP gene transcription. Collectively, these findings indicate that MMP7-catalyzed release of
HBEGF
mediates ACh-induced transactivation of
EGFR
and consequent proliferation of colon cancer cells. ACh-induced activation of
EGFR
and downstream
ERK
signaling also regulates transcriptional activation of MMP7, thereby identifying a novel feed-forward mechanism for neoplastic cell proliferation.
...
PMID:Acetylcholine-induced activation of M3 muscarinic receptors stimulates robust matrix metalloproteinase gene expression in human colon cancer cells. 1922 Oct 16
Regulation of nestin gene expression is largely unknown despite that it is widely used as a progenitor cell marker. In this study, we showed that nestin expression is regulated by the thrombin-mediated
EGFR
transactivation in serum-deprived primary cultures of rat vascular smooth muscle cells (VSMCs). This resulted from the direct binding of thrombin to PAR-1 rather than indirectly affecting through the binding to thrombomodulin, as demonstrated by thrombomodulin RNAi. In this process, the PAR-1-induced c-Src plays a critical role through two routes; one was the direct intracellular phosphorylation of
EGFR
and the other was the extracellular activation of the MMP-2-mediated shedding of
HB-EGF
. The transactivated
EGFR
then led to the downstream Ras-Raf-
ERK
signaling axis, but not the p38 or JNK pathways. In addition, the EMSA experiment showed that the transcriptional factor Sp1 is critical for the thrombin-induced nestin expression in rat VSMCs. Furthermore, RNAi of nestin attenuated the thrombin-induced cell proliferation, indicating that thrombin-induced nestin expression and cell proliferation share the same
EGFR
transactivation mechanism. This study also suggested that nestin may play an important role in cell proliferation induced by the thrombin-mediated
EGFR
transactivation.
...
PMID:Thrombin induces nestin expression via the transactivation of EGFR signalings in rat vascular smooth muscle cells. 1924 30
The effects of estradiol (E2) and of an AFP-derived cyclized peptide (cP) on the proliferation of primary cultures of cancer cells isolated from spontaneous canine mammary tumors were studied. The cellular response to E2 and cP was related to the expression of estradiol receptor (isoforms alpha and beta). In ER-positive cells, 2 nM estradiol increased cell proliferation and the phosphorylation of ERK1/2; 2 microg/ml cP inhibited all these effects. Estradiol also increased
HER2
immunoreactivity in ER-positive cells, an effect that was reverted to its basal values by cP. Estradiol stimulated in these cells the release of MMP2 and MMP9 and the shedding of
HB-EGF
, effects that the cP did not affect. ER-negative cells were refractory to estradiol or cP. All canine mammary tumor cells in culture responded to treatments analogously to human mammary cancer cells. Our results support the proposal of cP as a new, potentially effective therapeutic agent for the management of mammary cancer.
...
PMID:A cyclized peptide derived from alpha fetoprotein inhibits the proliferation of ER-positive canine mammary cancer cells. 1942 16
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