Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have purified and characterized a novel 30-kDa glycoprotein (gp30) with TGF alpha-like properties secreted from the estrogen receptor negative breast cancer cell line MDA-MB-231. This factor was immunoprecipitated by an anti-TGF alpha polyclonal antibody and also had TGF alpha-like biological activity, as assayed by EGF radioreceptor assay and anchorage-independent assays. In addition, the novel growth factor stimulated phosphorylation of the EGF receptor and erbB-2 receptor. However, the novel growth factor, unlike EGF and TGF alpha, bound to heparin-Sepharose. Purification of gp30 was obtained to apparent homogeneity by heparin affinity chromatography and subsequent reversed-phase chromatography. Tunicamycin treatment in vivo or N-glycanase deglycosylation in vitro revealed a putative precursor of approximately 22 kDa molecular mass in contrast to the "normal" 16-kDa precursor species for TGF alpha. In vitro translation of total mRNA from MDA-MB-231 cells confirmed the size of the putative precursor. Biochemical characterization of gp30 was begun by V8 protease digestion of the deglycosylated polypeptide and the translated products. Peptide mapping of V8-digested, immunoprecipitated material suggests that the amino acid sequence of this unique protein is distinct from mature TGF alpha and not the result of a posttranslational modification of the precursor. We conclude that this TGF alpha-like (gp30) polypeptide is a novel growth factor with agonistic activity for both EGF and erbB-2 receptors.
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PMID:Purification and characterization of a novel growth factor from human breast cancer cells. 132 10

We have previously shown that basic fibroblast growth factor (bFGF) inhibits the FSH-induced differentiation of cultured rat granulosa cells, as manifested by prominent reduction of the LH receptor expression. We now investigate the possible sites and mechanism of action of bFGF. Whereas bFGF decreased the cAMP formation induced by FSH, it enhanced the cAMP production caused by cholera toxin and forskolin, suggesting that bFGF exerted its inhibitory action on cell differentiation at a step to cAMP production. Photoaffinity labeling with 8-azido-[32P]cAMP revealed that bFGF markedly reduced the FSH-induced increase in the level of regulatory subunit RII beta of the cAMP-dependent protein kinase (PKA) type II. In contrast to its striking effect on RII beta expression (70-80% inhibition), bFGF decreased PKA enzymatic activity by only 30%. On the other hand, transforming growth factor-beta (TGF beta) slightly amplified the stimulatory action of FSH and antagonized the bFGF inhibitory effect on both LH receptor expression and RII beta synthesis. We report that the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol-13-acetate (TPA), which impaired granulosa cell differentiation, also abolished the RII beta synthesis induced by FSH. The activation of PKC by bFGF in granulosa cells was supported by the following findings: (i) bFGF markedly enhanced the production of diacylglycerol (2.3-fold stimulation at 5 min), the intracellular activator of PKC; (ii) bFGF promoted tight association of PKC to cellular membranes, a process that is believed to correlate with the enzyme activation; (iii) bFGF induced the phosphorylation of an endogenous M(r) 78,000/pI 4.7 protein that appears as a specific PKC substrate; (iv) bFGF mimicked the TPA-induced transmodulation of the epidermal growth factor (EGF) receptor, reducing by 36% the 125I-EGF binding on granulosa cells. We conclude that bFGF may exert its repressive action on RII beta synthesis, PKA activity, and granulosa cell differentiation by primarily targeting PKC activation.
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PMID:Regulation of cyclic adenosine 3',5'-monophosphate-dependent protein kinase activity and regulatory subunit RII beta content by basic fibroblast growth factor (bFGF) during granulosa cell differentiation: possible implication of protein kinase C in bFGF action. 132 4

In order to evaluate the possible contribution of phospholipase D (PLD) stimulation to the mitogenic response, a screening of a variety of different compounds, some of which are known to be potent mitogens, was performed using the well characterized Chinese hamster lung fibroblast (CCL39) cell line. In wild type CCL39 cells, or derivatives expressing high levels of either the human M1 muscarinic receptor (Hm1) or the human epidermal growth factor (EGF) receptor (39M1-81 and 39ER22 clones, respectively), thrombin, a potent mitogen for all three cell types, elicited the rapid activation of PLD (t1/2 activation, 30 s). Carbachol-mediated activation of the Hm1 receptor in the 39M1-81 clone, which is not a mitogenic signal, produced a similarly rapid although greater activation of PLD. Addition of EGF to the 39ER22 clone was able to provoke both a mitogenic response and stimulate PLD, albeit a comparatively small effect. In each case, the stimulation of PLD correlated closely with the ability to stimulate inositol phospholipid breakdown and was entirely dependent on the activation of protein kinase C. Moreover, the ability of both thrombin and carbachol to stimulate PLD was found to be rapidly desensitized, with a similar time course of desensitization (t1/2 desensitization, 90 s). It has recently been reported that an increase in phospholipase C (PLC)-mediated phosphocholine (PC) hydrolysis by either addition of agonist or by extracellular addition of PC-specific PLC enzyme constitutes a mitogenic signal. In this regard, in addition to stimulation of PLD, thrombin and carbachol were both able to stimulate the activity of a phosphocholine-specific phospholipase C (PC-PLC), which did not appear to desensitize within the time course employed. By contrast, EGF was unable to elicit the stimulation of PC-PLC. Ligands such as fibroblast growth factor (FGF) and platelet-derived growth factor (PDGF), which bind to and activate receptors with intrinsic tyrosine kinase activity, are potent mitogens for CCL39 cells but were unable to stimulate either PLD or PC-PLC activity. Furthermore, exogenous addition of purified PC-PLC enzyme, although able to induce a strong and lasting hydrolysis of PC, was unable to produce a mitogenic signal on its own. On the basis of these results, we conclude that the activation of both PLD and PC-PLC is neither sufficient nor required to produce a mitogenic response.
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PMID:Stimulation of phosphatidylcholine breakdown by thrombin and carbachol but not by tyrosine kinase receptor ligands in cells transfected with M1 muscarinic receptors. Rapid desensitization of phosphocholine-specific (PC) phospholipase D but sustained activity of PC-phospholipase C. 133 Oct 66

The expression and localization of epidermal growth factor (EGF) receptor were investigated immunohistochemically using anti-EGF receptor antibody in the normal rat liver and 3'-methyl-4-dimethylaminoazobenzen (3'-Me-DAB) induced tumors in rats. In 8 weeks after 3'-Me-DAB treatment, multiple nodules of cholangiocarcinoma were found in the rat liver, and atypical nodules of hepatocytes were also found 14 weeks later. Immunoreactive products against EGF receptor were only slightly positive in the normal liver, the nodule of cholangiocarcinoma, and atypical nodule of hepatocytes. It was noted that EGF receptor immunoreactivity was more intense in non-cancerous tissue adjacent to tumorous nodules than in the cancerous tissue. The present finding suggests that the expression of EGF receptor may be associated with regenerating as well as carcinogenetic processes in the rat liver.
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PMID:Immunohistochemical study on epidermal growth factor (EGF) receptor during carcinogenesis in the rat liver. 133 35

Selective inhibitors of tyrosine kinases, tyrphostin 23 and genistein, produced concentration-dependent inhibition of voltage-operated calcium channel currents in vascular smooth muscle cells isolated from rabbit ear artery. The potency of these two structurally dissimilar inhibitors was similar to that reported for their action as inhibitors of tyrosine kinases. Daidzein, an inactive analogue of genistein, had little inhibitory effect on calcium channel currents at concentrations below 300 microM consistent with an action of these agents at a tyrosine kinase. However, tyrphostin 1, a reportedly less active tyrphostin derivative, also inhibited calcium channel currents with a potency similar to tyrphostin 23. These findings suggest that voltage-operated calcium channels in vascular smooth muscle may be modulated by endogenous tyrosine kinase(s) which display different sensitivities to inhibitors compared with the epidermal growth factor (EGF) receptor. Alternatively the possibility of direct blocking actions of these inhibitors at voltage-operated calcium channels cannot be excluded.
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PMID:Tyrosine kinase inhibitors block calcium channel currents in vascular smooth muscle cells. 133 77

Among the various factors reported as having significant prognostic value in primary breast cancers, the author discusses the value of well established "classical" prognostic factors used routinely and "new" prognostic factors developed over recent years as a result of progress in cell and molecular biology. The presence of axillary lymph node metastases remains the most important prognostic factor of recurrence, justifying post-surgical adjuvant therapy. However, in patients with negative axillary nodes (N-), the size of the tumour, Scarff-Bloom-Richardson (SBR and MSBR) histological grade, certain particular histological types (carcinoma in situ and tubular, colloid or pure papillary cancer) and hormone receptors (ER and PR) appear to be well established prognostic factors allowing the identification, within this group of N- patients who generally have a good prognosis, those patients with a low risk of recurrence and therefore not requiring adjuvant therapy. In contrast, the proliferative activity (ploidy and S phase, Thymidine Labeling Index, antibody Ki67), cathepsin D, thymidine kinase, EGF receptors, several genes including oncogene HER-2/neu, are recently developed prognostic factors whose significance needs to be confirmed by further studies.
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PMID:[Prognostic factors in breast cancer]. 134 Jan 64

HER-2/neu oncogene protein, epidermal growth factor receptor, progesterone receptor, and estrogen receptor were examined immunohistochemically in specimens of normal and neoplastic endometrium. Tissues obtained at the time of hysterectomy were snap-frozen at liquid nitrogen temperature and serially sectioned at 4 microns. Normal endometrial epithelial cells stained with anti-epidermal growth factor receptor and anti-HER-2/neu with intensities graded from 0 to 3+. Of the 49 endometrial malignancies studied, seven (14%) contained tissue exhibiting HER-2/neu staining in excess (4+) of any of the normal tissues or the other 42 cancer specimens. Expression of both HER-2/neu and steroid receptors was heterogeneous within these seven tumors. To examine this heterogeneity more closely, sections of these and other tumors were double-stained for HER-2/neu and progesterone receptor. It was found that the cells exhibiting 4+ HER-2/neu staining were progesterone receptor-negative. Conversely, cells that were progesterone receptor-positive within the same specimen exhibited HER-2/neu immunostaining equal to or less than 3+. All specimens containing 4+ HER-2/neu tissue were graded 1 or 2 adenocarcinomas, stage I. Thus, there is an inverse relationship between overexpression of HER-2/neu and progesterone receptor in endometrial cancer. On the other hand, overexpression of HER-2/neu in endometrial cancer does not seem to be related to loss of other differentiated characteristics. The prognostic value of these observations awaits continued study.
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PMID:Immunohistochemical study of HER-2/neu, epidermal growth factor receptor, and steroid receptor expression in normal and malignant endometrium. 134 72

Using sections of formalin-fixed, paraffin-embedded tissues from 64 colorectal cancer patients, the expression of c-erbB-2 oncoprotein was studied immunohistochemically. Twenty-seven percent of the cases with liver metastasis showed positive staining. On the other hand, only 3% of cases without liver metastasis were positive. Expression rates of c-erbB-2 protein in liver metastasis cases showed no significant difference between primary operation (26%) and recurrence (27%). Of all c-erbB-2 positive patients, 90% (9/10) had liver metastasis. Secondly, vessel invasions of 45 rectal cancer patients were studied using Victoria Blue (VB) elastic staining and endothelial staining by factor VIII-related antigen and Ulex europaeus agglutinin I (UEA-I) lectin. VB-HE double stain was efficacious to detect vascular invasion, but endothelial staining was not. There were statistically more vascular invasions in 30 patients with liver or lymph node metastases than in those without metastasis. And in cases with metastasis, many vascular invasions into the extra-muscular layer were seen. Both vascular invasions and c-erbB-2 protein were valuable indicators of possible liver metastasis.
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PMID:[Expression of c-erbB-2 protein and vessel invasion in colorectal cancer]. 134 87

Overexpression of the c-erbB-2/neu protooncogene has recently been shown in ovarian tumors collected from the United States. It is known that environmental and cultural factors may contribute to certain types of cancer, therefore, we examined expression of c-erbB-2/neu in ovarian tumors collected from China by immunohistochemical staining. Out of 81 tumor specimens, 57 (70.4%) were found to be immunopositive, whereas only one out of 17 (5.9%) normal ovarian tissue samples was slightly positive. Our results indicate that overexpression of c-erbB-2/neu is a general phenomenon for ovarian cancer regardless of different population. To search for a c-erbB/neu overexpressing cell line for future study on molecular mechanism, we also analyzed 13 cancer cell lines from the female genital tract for expression of c-erbB-2/neu. The c-erbB-2/neu RNA was found to be overexpressed at least 100-fold in one of the four ovarian cancer cell lines examined. An aberrant c-erbB-2/neu RNA was also found to be overexpressed in this cell line. Southern blot analysis indicated that the c-erbB-2/neu was amplified 2-4-fold in this line, and some of these alleles have structural alteration which may account for expression of the aberrant c-erbB-2/neu RNA. Since the 2-4-fold gene amplification is not proportional to the greater than 100-fold overexpression in RNA, other mechanisms such as transcriptional or posttranscriptional control must be involved in overexpression of this gene in ovarian cancer.
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PMID:Aberrant expression of the c-erbB-2/neu protooncogene in ovarian cancer. 134 99

Of 221 patients with breast cancer of known epidermal growth factor receptor (EGFR) and oestrogen receptor (ER) status, 99 had developed recurrences during the period of follow-up (range 3-60 months, median 24 months). Of these, 72 received endocrine therapy as first-line treatment for relapse. Immunohistochemical assessment of c-erbB-2 protein product expression was made using paraffin-embedded tumour tissue from 65 of these 72 patients. Including patients whose disease remained stable for more than 6 months with those showing an objective response (CR or PR for more than 3 months), only one (7%) of 14 c-erbB-2 positive tumours responded to endocrine manipulation compared with 19 (37%) of 51 c-erbB-2 negative tumours (P less than 0.05). Coexpression of c-erbB-2 reduced the response rate of ER positive patients from 48% to 20% and of ER negative cases from 27% to 0% (P less than 0.01). EGFR and c-erbB-2 protein appeared to have additive effects in reducing the likelihood of response, and none of eight patients with EGFR positive, c-erbB-2 positive tumours derived benefit from endocrine therapy. The results of this study suggest that c-erbB-2 protein overexpression, a marker of poor prognosis in breast cancer, is associated with a lack of response to endocrine therapy on relapse, and particularly in combination with EGFR may be useful in directing therapeutic choices.
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PMID:Relationship between c-erbB-2 protein product expression and response to endocrine therapy in advanced breast cancer. 134 66


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