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Query: UNIPROT:P04626 (
erbB-2
)
5,251
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The induction of prostaglandin G/H synthase (PGHS; prostaglandin endoperoxide synthase, cyclooxygenase) by proinflammatory cytokines accounts, at least in part, for the altered eicosanoid biosynthesis in inflammatory diseases. In secondary cultures of normal human bronchial epithelial cells (NHBECs), interferon-gamma (IFN-gamma, 10 ng/ml for 24 h) increased the amount of prostaglandin E2 (PGE2) released in response to stimulation with exogenous arachidonic acid (5 microM). The enhanced production of PGE2 reflected the upregulation of PGHS-2 as indicated by enhanced expression of PGHS-2 RNA and increased recovery of PGHS-2 protein in NHBECs. IFN-gamma did not alter the production of PGE2 in A549 cells (a human lung adenocarcinoma cell line) or 6-keto-PGF1alpha in human umbilical vein endothelial cells (HUVECs), although prostaglandin release and/or the expression of PGHS-2 RNA in these cell lines was upregulated by other proinflammatory cytokines. Induction of PGHS-2 RNA in IFN-gamma-treated NHBECs, which peaked at 24 h, suggested the presence of an intermediary substance regulating the expression of PGHS-2. When the binding between the
epidermal growth factor (EGF) receptor
and its ligands was disrupted by a neutralizing antibody (LA-1), IFN-gamma failed to upregulate the release of PGE2 and the expression of PGHS-2 RNA in NHBECs. Furthermore, IFN-gamma induced the expression of RNAs for a number of ligands at the EGF receptor
TGF-alpha
; heparin-binding EGF-like growth factor (HB-EGF); and amphiregulin in NHBECs, and when administered exogenously, these ligands increased PGE2 release from NHBECs. Heparin at the concentration that neutralized the function of amphiregulin, or antibodies against TGFalpha or HB-EGF also reduced the release of PGE2 from IFN-gamma-stimulated NHBECs. These data are consistent with the presence of an autocrine growth factor/EGF receptor loop regulating PGHS-2 expression and PGE2 synthesis in bronchial epithelial cells.
...
PMID:Interferon gamma induces prostaglandin G/H synthase-2 through an autocrine loop via the epidermal growth factor receptor in human bronchial epithelial cells. 906 64
Although in Fischer-344 rats aging is found to be associated with increased gastric mucosal proliferative activity, little is known about the intracellular events that regulate this process. The present investigation examines the age-related changes in gastric mucosal tyrosine kinase activity and expression of epidermal growth factor receptor(EGFR) and its structural and functional analog p185c-
erbB-2
, the protein product of c-
erbB-2
/c-neu protooncogene. We observed a significantly higher intrinsic tyrosine kinase activity and tyrosine phosphorylation of EGFR and p185c-
erbB-2
in the gastric mucosa of 24-mo-old (aged) rats than in that of their 4- or 12-mo-old counterparts. This was associated with increased levels of EGFR protein and steady-state mRNA levels of EGFR and p185c-
erbB-2
. In addition, we also observed threefold higher steady-state mRNA levels of transforming growth factor-alpha (
TGF-alpha
; one of the primary ligands of EGFR) in the gastric mucosa of aged rats than in that of 4-mo-old (young) animals. This was accompanied by a fivefold increase in the relative concentration of the 18-kDa precursor form of
TGF-alpha
in gastric mucosal membranes but not in the cytosol. In conclusion, our data demonstrate that aging is associated with increased tyrosine kinase activity of EGFR and p185c-
erbB-2
in the gastric mucosa. Moreover, the observation that aging results in increased accumulation of
TGF-alpha
in gastric mucosal membranes raises the possibility that the membrane-bound
TGF-alpha
could partly be responsible for the constitutively active EGFR-induced signaling pathway in the gastric mucosa of aged rats and, in turn, for stimulation of mucosal proliferative activity.
...
PMID:Increased expression of EGFR in gastric mucosa of aged rats. 927 18
The extrauterine development of marsupial pouch young (northern brown bandicoot Isoodon macrourus) has facilitated the study of the effects of murine epidermal growth factor (mEGF) on pattern formation in skin. Hair follicle initiation and development, which in the mouse would occur from about Days 13-14 of gestation onward, occurs postnatally. In the present study the effect in vivo of mEGF on developing skin corresponding to mouse gestational ages from Day 13 onward was examined. Subcutaneous injections of mEGF (0.5, 1.0 and 2.0 microg g[-1] body weight) or equivalent volumes of saline (0.9% w/w) were administered daily, before and during hair follicle initiation and development. Murine EGF inhibited the formation of hair follicles, hair follicle sweat glands, sebaceous glands and dermal papillae. The pattern of follicle initiation was perturbed. The characteristic trio follicle grouping was absent, and follicle rudiment densities (no. per mm2 skin surface) were significantly lower in animals treated with mEGF, whereas follicle diameters were increased. These data may reflect a role for the
epidermal growth factor (EGF) receptor
in epidermal pattern formation. The EGF receptor and its potential ligands (such as EGF, transforming growth factor (
TGF-alpha
) or other yet-to-be-discovered ligands) perhaps act as parts of a pattern-forming system in vertebrate skin.
...
PMID:In vivo effects of epidermal growth factor on epidermal pattern formation and hair follicle initiation in the marsupial bandicoot Isoodon macrourus. 941 78
Pulmonary epithelial cells are important in lung growth, development, and injury. H441 pulmonary adenocarcinoma cells may be a useful model for studying pulmonary epithelial cell growth factor responses in vitro. Isolated pulmonary epithelial type II cells proliferate in response to transforming growth factor (TGF)-alpha via the
epidermal growth factor (EGF) receptor
. Type II cells also proliferate in response to hepatocyte growth factor (HGF). In the present study, H441 cell responses to these growth factors were examined, and compared to type II cells. Both the EGF-R and the c-met proto-oncogene receptor, to which HGF binds, were immunoprecipitated from H441 cells. In H441 cells, addition of
TGF-alpha
resulted in phosphorylation of the EGF receptor and increased cell number and tritiated thymidine incorporation. Incubation with HGF resulted in phosphorylation of its c-met proto-oncogene receptor in type II and H441 cells, and also increased cell number and tritiated thymidine incorporation. Both HGF and
TGF-alpha
stimulated phosphorylation of the intracellular signaling molecules p42 and p44 mitogen activated protein kinases in H441 cells. H441 cells exhibited responses to mitogenic growth factors similar to type II cells and may be useful as a model for type II cell growth factor responses and signal transduction.
...
PMID:H441 pulmonary epithelial cell mitogenic effects and signaling pathways in response to HGF and TGF-alpha. 945 67
Over-expression of
erbB-2
is associated with shortened survival of patients with lung adenocarcinomas. We demonstrated that human lung epithelial cells, overexpressing
erbB-2
, formed tumours in nude mice only when high levels of transforming growth factor (TGF)-alpha were produced (E6T cells). To define the role that
TGF-alpha
production played in induction of tumorigenicity, a non-tumorigenic
TGF-alpha
-negative clone of ErbB-2 overexpressing cells (E2 cells) was transfected with an expression vector for
TGF-alpha
(E2alpha cells). Transfected clones produced
TGF-alpha
at 11-25% of the level produced by the E6T cell line. Tumorigenic E6T cells transfected with a
TGF-alpha
antisense vector (E6TA cells) expressed only 6% of the
TGF-alpha
level of the parental cells. Clones of E6T, E6TA, E2 and E2alpha were inoculated into athymic nude mice to measure tumorigenic potential. E6T cells formed tumours with a 70% efficiency. E2, E6TA and E2alpha cells failed to form tumours. The levels of EGFR were similar in non-tumorigenic E2 and tumorigenic E6T cells but higher in E2alpha and E6TA cells, and ErbB-2 were greatly overexpressed in an E2alpha clone. In vitro, ErbB-2 co-immunoprecipitated with EGFR in lysates of unstimulated E6T and E2alpha
TGF-alpha
-producing cells, indicating that the lower
TGF-alpha
levels were sufficient to induce in vitro heterodimerization. These studies suggest that induction of the tumorigenic phenotype depends on achieving a threshold level of
TGF-alpha
sufficient to activate downstream signalling by ErbB-2 containing active heterodimers.
...
PMID:The role of transforming growth factor alpha production and ErbB-2 overexpression in induction of tumorigenicity of lung epithelial cells. 956 41
The investigation of a N-terminally truncated human transforming growth factor-alpha (
TGF-alpha
; residues 8-50) has been completed to determine the contribution of the N terminus to receptor binding and activation. The deletion protein was proposed and designed through study of NMR relaxation and nuclear Overhauser enhancement data obtained from the
TGF-alpha
-
epidermal growth factor (EGF) receptor
complex, which indicated that the residues N-terminal to the A loop remain flexible in receptor-bound
TGF-alpha
and thus suggested their lack of involvement in receptor binding (Hoyt, D. W., Harkins, R. N., Debanne, M. T., O'Connor-McCourt, M., and Sykes, B. D. (1994) Biochemistry 33, 15283-15292; McInnes, C., Hoyt, D. W., Harkins, R. N., Pagila, R. N., Debanne, M. T., O'Connor-McCourt, M., and Sykes, B. D. (1996) J. Biol. Chem. 271, 32204-32211).
TGF-alpha
8-50 was shown to have approximately 10-fold lower affinity for the receptor than the native molecule in an assay quantifying the ability to compete with EGF for binding and to have a similar reduction in activity as indicated by a cell proliferation assay. NMR solution structural calculations on this molecule demonstrate correct formation of the three disulfide bonds of
TGF-alpha
8-50 and have established the presence of native secondary structure in the B and C loops of the protein. However, some perturbation of the global fold with respect to the orientation of the subdomains was observed. These results suggest that although the N-terminal residues do not contribute directly to binding, they make a significant contribution in defining the conformation of the growth factor, which is required for complete binding and activity and is therefore significant in terms of producing native folding of
TGF-alpha
. They also show that information obtained from the receptor-bound ligand can be used to guide the design and minimization of
TGF-alpha
analogues. The implications of the study of
TGF-alpha
8-50 for the design and synthesis of reductants of this growth factor are therefore discussed.
...
PMID:Structure-based minimization of transforming growth factor-alpha (TGF-alpha) through NMR analysis of the receptor-bound ligand. Design, solution structure, and activity of TGF-alpha 8-50. 976 63
Adenocarcinoma of the pancreas carries a grave prognosis for affected patients. Certain oncogenes (K-ras and
HER-2/neu
) are mutated in a large proportion of these aggressive tumors. Adenocarcinoma of the pancreas has also been associated with loss of tumor suppressor genes (p53, DPC4, p16/MTS), either by deletion or by mutation and loss of function. Growth factors (EGF,
TGF-alpha
, HGF) and growth factor receptors (EGF-R, c-met, CCK) are expressed at levels not found in the normal pancreas. Finally, factors important for angiogenesis (FGF, integrins, selectins) are likely to play an important role in the growth and metastasis of clinically relevant tumors. This review attempts to summarize and assimilate current research into the molecular and cellular biology of pancreatic cancer.
...
PMID:The molecular and cellular biology of pancreatic cancer. 980 1
The role of estrogen and estrogen-related growth factors in the mechanism of hormone dependency of endometrial adenocarcinoma cells was investigated. The proliferation of hormone-responsive human endometrial adenocarcinoma cells (Ishikawa cells), which possess both estrogen and progesterone receptors, was optimally stimulated by 10 nM estradiol. Both transforming growth factor (TGF)-alpha and epidermal growth factor (EGF), added to the culture media, stimulated the proliferation of Ishikawa cells in a dose-dependent manner. Anti-
TGF-alpha
antibody completely eliminated the stimulatory effects of
TGF-alpha
. Anti-EGF receptor antibody inhibited the proliferation of these cells. The production of
TGF-alpha
into culture media was 5-40 pg/10 cells/24 h in 9 human endometrial adenocarcinoma cells. Ten nanomoles of estradiol increased the
TGF-alpha
production of Ishikawa cells by approximately 2.5-fold of the control level. In contrast, the production of
TGF-alpha
in hormone-unresponsive HEC-50 cels was not influenced by estradiol.
C-erbB-2
oncoprotein expression of human endometrial adenocarcinoma cells, detected by both immunocytochemical staining and Western blot analysis, was associated with the tumor grade of the original tumor tissues. Ten nanomoles of estradiol clearly increased the c-
erbB-2
oncoprotein levels at an optimal incubation period of 72 h, whereas estradiol did not affect the expression in HEC-50 cells.
...
PMID:Role of estrogen and estrogen-related growth factor in the mechanism of hormone dependency of endometrial carcinoma cells. 985
The mammary gland seems to be the only organ that is not fully developed at birth. Estrogens stimulate breast tissue via estrogen receptors (ERs). In the mammary gland, ER-mediated mechanisms have been shown to regulate: various growth factors, such as
TGF-alpha
and TGF-beta; enzymes, such as cathepsin D and plasminogen-activator; proto-oncogenes, such as c-fos, c-myc and
HER-2/neu
; cyclines and other regulatory substances that provide signaling systems for cell division and differentiation; other steroid receptors and epidermal growth factor receptors. Estrogen target genes contain estrogen-responsive elements. In these genes, transcription will be activated through interaction with the estrogen/ER protein complex. Subsequent activation of proto-oncogenes provides an explanation for the stimulating effect of estrogens on the glandular breast. Progesterone may be the key in influencing the risk of breast cancer with the peak of mitotic activity in the breast during the luteal phase of the menstrual cycle. On the other hand, in human breast cancer cell lines, both proliferation and inhibition have been observed with various progestational agents. Relevant biological and clinical issues are pregnancy and exposure to exogenous hormones. The intense hormonal stimulation of pregnancy (both estrogen and progesterone) has no adverse impact on the course of breast cancer. Pregnancy, with its mammogenetic differentiation, results in the protection of this organ from carcinogenesis. Characterization of specific lobular morphology serves as an indicator of the level of differentiation achieved by the organ, and thus provides means to assess the risk of the gland undergoing neoplastic transformation when exposed to given agents. Sufficient evidence exists to indicate the possibility of a slightly increased risk of breast cancer after approximately one decade of postmenopausal estrogen use. A review of the epidemiologic studies of postmenopausal hormone replacement and the risk of breast cancer fails to provide definitive evidence. Recent information derives from observations of cellular proliferation, plasma and tissue estradiol and progesterone receptor levels, and the percentage of apoptotic epithelial cells in human breast tissue. Several studies suggest that short-term, continuous combined HRT does not increase breast cancer recurrence or mortality. The participation of sexual hormones in the mammogenetic process during pregnancy might serve as an intermediate end point in assessing the effectiveness of hormones as chemopreventive agents. Investigations based on history, and breast morphology, should enable us to select estrogens and progestogens for HRT, and adopt optimal therapeutic regimens.
...
PMID:Potential benefits of estrogens and progestogens on breast cancer. 992 May 36
An NCI-sponsored, phase II trial of N-(4-hydroxyphenyl)- retinamide (4-HPR) in patients with organ-confined prostate cancer in the period prior to radical prostatectomy was carried out. Thirty-seven men with the histologic diagnosis of prostate cancer planning to have radical prostatectomy entered the study after informed consent and were given 4-HPR (or matching placebo) as a single daily dose (two 100-mg capsules of 4-HPR or two capsules of placebo daily) for 3 weeks prior to surgery. Four men dropped out for unrelated reasons. Thirty-three men completed the study. At the time of surgery, repeat biopsies of the prostate were performed to study the effects of the drug on potential surrogate endpoint biomarkers (SEBs) of malignancy within the tissue. The panel of potential SEBs of malignancy include p53, cytomorphometric indices, ploidy, PNCA,
erbB-2
, erbB-3, EGF receptor,
TGF-alpha
tumor-associated glycoprotein-72, fatty acid synthetase and Lewis Y antigen. Twenty-three patients had matching pre- and posttherapy lesions and were considered informative. Results from the patients indicate significant differential expression of biomarkers in pretreatment specimens of uninvolved prostatic tissue (normal-appearing epithelia) prostatic intraepithelial neoplasia (PIN) and prostate cancer. The mean
erbB-2
expression was 0.58 in uninvolved vs. 1.04 in PIN (p = 0.002); while the mean
erbB-2
expression was 1.35 in prostate cancer (p = 0.0007, uninvolved vs. prostate cancer). A similar pattern of increased biomarker expression between uninvolved and PIN or prostate cancer tissues can be observed for EGF receptor (mean = 1.21, 1.87 and 1.76 for uninvolved, PIN and prostate cancer, respectively) and erbB-3 (mean = 0.81, 1.59 and 1.30 for uninvolved, PIN and prostate cancer, respectively). There were no statistically significant differences in biomarkers observed in the 4-HPR-treated patients when compared with placebo-treated control patients. There was a posttreatment up-regulation of biomarkers observed in both groups of patients. This observation is most likely explained by an effect due to the diagnostic sextant biopsy equally affecting both groups of patients. Results from this study do not demonstrate a chemoprevention effect of 4-HPR on tissue-based SEBs at the dose given.
...
PMID:Evaluation of biomarker modulation by fenretinide in prostate cancer patients. 1032 1
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