Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

These studies attempt to analyze the basis of the estrogenic and antiestrogenic action of three nonsteroidal clomophene-type compounds as monitored by their ability to bind to immature rat uterine cytoplasmic estrogen receptor, transfer receptor sites to the nucleus, and elicit estrogenic responses (increased uterine weight and induction of the synthesis of a specific uterine protein, called induced protein, or "IP"), and by their ability to antagonize the effects of estradiol on these receptor interactions and uterine responses. Both CI-628 (CI) and U-11, 100A (UA) [50 mug] elicit slight IP induction at 1-2 hand give pronounced uterine weight increases at 24 h but feeble increases at 72 h (3 single daily injections). Both bind to cytosol, and effect the transfer of receptor sites to the nucleus, which may account for the estrogenicity of these compounds. Both CI and UA give rapid (by 2-4 h), prolonged (for over 24 h), and complete blockage of estradiol-stimulated treatment abolishes short-term estradiol-stimulated uterine weight increase and antagonizes the 72 h estradiol-stimulated uterine weight response to the level attributable to the antiestrogen alone. MER-25, at the same dose (50 mug), had no estrogenic or antiestrogenic activity. Both CI and UA rapidly deplete the cytoplasmic estrogen binding capacity, reducing it to barely detectable levels for 24-42 h. Although during this period, no IP or uterine wet weight response can be elicited by estradiol, administration of saturating levels of [3H]estradiol in vivo or in vitro results in the appearance of considerable [3H]estradiol in the nucleus, bound to a macromolecule sedimenting identically with that of the nuclear receptor-estradiol complex (5.5S) formed in the absence of prior antiestrogen exposure. Hence, the estradiol which becomes bound in the nucleus after antiestrogen is biologically ineffective. The return of IP responsiveness after antiestrogen correlates well with the level of cytoplasmic receptor capable of translocation to the nucleus, and not with the nuclear estradiol uptake capacity, Presumably, then, the antiestrogenic action of CI and UA results from their depletion of cytoplasmic receptor sites and not from their ability to block specific estradiol-nuclear receptor binding per se. These studies indicate that one should be cautious in assuming that the magnitude of an estrogen response is necessarily related to the level of estrogen receptor complex in the nucleus.
...
PMID:Antiestrogen action in the uterus: biological ineffectiveness of nuclear bound estradiol after antiestrogen. 16 21

Amplification of the c-myc and HER2/neu genes was found in 20 and 23%, respectively, of primary breast cancer tissues derived from 282 patients (median follow-up, 74 months). c-myc amplification was observed more frequently in larger tumors (P = 0.01) and in lymph node-positive patients (P = 0.01) but was not associated with age, menopausal status, or with differentiation grade or steroid receptor status. c-myc amplification was strongly negatively correlated with HER2/neu amplification (P less than 0.001). In univariate analysis, amplification of c-myc proved to be a significant predictor of reduced relapse-free and overall survival (for both, P less than 0.001). In multivariate analysis for relapse-free survival, c-myc amplification significantly (P = 0.001) added to the prognostic power of tumor size (P less than 0.001), lymph node status (P less than 0.001), and estrogen receptor status (P = 0.003), with the highest relative failure rate (1.8) after lymph node status (2.2). In this pilot study, c-myc amplification was predictive for outcome, especially among patients with node-negative disease or steroid receptor-positive tumors; 51 and 46% differences in actuarial 5-year recurrence rates when compared to patients with tumors with normal c-myc gene copy numbers, respectively. HER2/neu amplification was not associated with relapse-free survival but weakly with shorter overall survival in univariate analysis (P = 0.035). Only in the relatively small subgroup of steroid receptor-negative tumors, HER2/neu amplification may identify those patients with an increased risk of death. In conclusion, amplification of c-myc is an independent powerful prognosticator, particularly in node-negative and steroid receptor-positive breast cancer, whereas HER2/neu amplification may be of limited prognostic value, only in steroid receptor-negative disease.
...
PMID:c-myc amplification is a better prognostic factor than HER2/neu amplification in primary breast cancer. 173 70

To refine the analysis of gene amplification in breast cancer, the authors have developed sensitive methods that can be used to screen nucleic acid prepared from a variety of sources. In their analysis, Southern hybridization and DNA dot-blot analysis were used to screen 49 breast cancer DNAs for Myc, Neu, and Int-2 gene amplification. The analysis detected minimal one extra gene copy) as well as expanded (two or more extra gene copies) gene amplifications, and in addition, distinguished between gene amplification and aneuploidy as the cause of extra gene copies. These quantitative methods were adapted to patient specimens routinely available in the anatomic pathology laboratory, including fresh tumor tissue, tumor nuclei discarded during estrogen receptor analysis, and paraffin blocks. One minimal gene amplification was found in three cases of intraductal cancer. Of 25 cases of nonmetastatic invasive cancer, 28% had at least one extra Myc gene, whereas 24% had Neu, and 21% had Int-2 gene amplification. Of 21 cases of metastatic invasive cancer, 43% had Myc, 43% had Neu, and 40% had Int-2 gene amplification. Among the nonmetastatic cancers, 47% had one, 12% had two, and 4% had three amplified genes. Within the metastatic cancers, 48% had one, 28% had two, and 5% had three amplified genes. Our data suggest relationships between tumor progression and both incidence and size of Myc, Neu, and Int-2 gene amplification.
...
PMID:Oncogene amplification in breast cancer. 184 59

Twelve male patients with operable breast cancer were evaluated for the expression of prognostic factors by immunohistochemical staining assay. Seven patients were stage I & II, and five patients were stage III. Axillary lymph node positivity was 42%. Nine patients were nuclear grade I, three were nuclear grade II, and none were nuclear grade III. The expression rate of EGFR (epidermal growth factor receptor), ER (estrogen receptor) were 8.3%, 70.0% respectively. This limited data suggest better tumor behavior in male than in female breast cancer. Adjuvant treatment should be considered in male breast cancer just as in females, based on axillary lymph node and ER states.
...
PMID:Expression of prognostic factors (EGFR, ER) by immunohistochemical staining method in male breast cancer. 194 15

The expression of the pS2 gene, which is induced by estrogen in the breast cancer cell line MCF-7, has been investigated in breast cancers by using pS2 mRNA determination in tumor specimens and immunocytochemistry to identify pS2 protein in paraffin-embedded sections. Using these assays we show that determination of pS2 gene expression allows the definition of subclasses of estrogen-receptor-containing breast cancers that may be used to more precisely identify estrogen-dependent tumors. Tumor specimens have also been analyzed for the presence of mRNAs for the estrogen receptor and for the ERBB2 oncogene. No evidence for the presence of truncated forms of estrogen-receptor mRNA has been found, and overexpression of the ERBB2 oncogene did not correlate with the steroid receptor status or pS2 gene expression.
...
PMID:Specific expression of the pS2 gene in subclasses of breast cancers in comparison with expression of the estrogen and progesterone receptors and the oncogene ERBB2. 332 Oct 71

Experiments were conducted to determine why tamoxifen, a non-steroidal antiestrogen, is uterotrophic in mice, whereas MER-25 (ethamoxytriphetol), a structurally related compound, is antiuterotrophic. Initial experiments indicated that the pituitary was not required for a uterotrophic response in mice to either estradiol (E2), tamoxifen (TAM), or 4-hydroxytamoxifen (4-OH-TAM) MER-25 was not uterotrophic in mice but was capable of completely inhibiting the uterotrophic responses of mice to estrogens (E2) as well as antiestrogens (TAM and 4-OH-TAM); this inhibition was reversible by increasing the dose of the antiestrogen (TAM). The relative binding affinities (RBA) of TAM, 4-OH-TAM, and MER-25 to mouse uterus estrogen receptor (ER) and mouse liver antiestrogen binding sites (AEBS) were compared to determine whether either (or both) of these sites mediate the biological effects of these compounds. E2 is arbitrarily assigned an RBA of 100 for ER; similarly, TAM is assigned an RBA of 100 for AEBS. MER-25 bound to AEBS with an RBA of 8.9 and to ER with an RBA of less than 0.06; in contrast, TAM and 4-OH-TAM bound to AEBS with RBAs of 100 and 53, respectively, and to ER with RBAs of 2 and 131, respectively. Five other compounds that had similar RBAs as MER-25 for AEBs (RBAs in the range 4-9) and for ER (RBAs less than 0.06) were tested for their antiuterotrophic activities in vivo against both estrogen (E2) and antiestrogen (TAM) in ovariectomized mice. None of these compounds were antiuterotrophic against either estradiol or tamoxifen (P less than 0.01), nor were any of the compounds uterotrophic in mice. These data suggest that differences in the biological actions of tamoxifen and MER-25 in mice are not mediated through AEBS and are most likely due to differences in their interactions with ER.
...
PMID:Possible mechanisms for the agonist actions of tamoxifen and the antagonist actions of MER-25 (ethamoxytriphetol) in the mouse uterus. 401 16

Administration of the antiestrogen ethamoxytriphetol (MER-25) during baboon gestation results in a marked decline in placental progesterone production. Since this effect in primates may be modulated via an estrogen receptor, the present study investigated the possible existence of an estrogen receptor in human placenta. Villous tissue of human, term placentas was homogenized in 0.01M Tris-HCl, ethylenediaminetetraacetic acid, dithiothreitol, glycerol buffer. Cytosol was incubated with 10(-8)M [3H] 17 beta-estradiol (E2) in the presence or absence of 10(-6)M diethylstilbestrol (DES). A single peak of [3H]E2 binding occurred in the 5.2 S region after glycerol density gradient centrifugation, which was competed for by DES, E2, and enclomiphene. Scatchard analysis demonstrated E2 binding, which was saturable, of high affinity (Kd = 1.90 X 10(11)M) and of low capacity (N = 0.13 X 10(-14) moles/mg cytosolic protein). Competition for [3H]E2 binding was DES greater than E2 greater than estrone greater than MER-25 greater than enclomiphene, whereas androgens, progestins, and corticosteroids were ineffective. The results fulfill the criteria for a specific estrogen receptor. The influence of antiestrogen and, possibly, estrogen upon placental function in baboons may be modulated by an estrogen receptor.
...
PMID:A specific cytosolic estrogen receptor in human term placenta. 714 4

Antagonists of steroid hormones are clinically important in the management of breast cancer. However, the duration of response is limited due to the development of hormone-independent tumors in virtually all cases. In an attempt to obtain insight into the mechanisms underlying antiestrogen resistance, the consequences of epigenetic changes in gene expression were studied in vitro. Estrogen-dependent ZR-75-1 human breast cancer cells were treated with 5-azacytidine, an inhibitor of DNA methylation, and cultured in the absence of estradiol or in the presence of antiestrogens. Estrogen-independent cell colonies developed within 3 weeks at high frequency in 5-azacytidine-treated cultures (0.7 x 10(-3), in contrast to control cultures (< or = 10(-8). The derived cells (ZR/AZA) were resistant to 4-hydroxytamoxifen and ICI 164,384, independent of the selection protocol, but had lost the ability to grow anchorage-independent. Whereas expression of estrogen receptor, progesterone receptor, and pS2 were down-regulated, expression of epidermal growth factor (EGF) receptor and HER2/neu were increased in ZR/AZA cells. In contrast to the stable altered expression patterns of estrogen receptor and EGF receptor, transient keratin 7 expression was observed. Transforming growth factor-alpha mRNA was identified in ZR-75-1 cells and ZR/AZA cells and EGF-like peptides were secreted in the culture medium. Proliferation of ZR/AZA cells could be partially inhibited with an EGF receptor-blocking antibody. Presence of both growth factor receptors and possible ligands suggests the development of an autocrine growth mechanism. Our data show that epigenetic alterations of gene expression result in rapid progression of breast cancer cells to hormone independence.
...
PMID:Induction of estrogen independence of ZR-75-1 human breast cancer cells by epigenetic alterations. 753 60

The retinoid N-(hydroxyphenyl) retinamide (4-HPR) appears to be a promising tool for chemoprevention of breast carcinoma, and clinical trials to evaluate its effect are in progress. However, its action on tumor cells has remained largely undefined. We report here that 4-HPR induced apoptosis and/or differentiation in breast cancer cell lines, independent of hormone receptor status and retinoic acid receptor expression, although it was slightly more efficient in inhibiting proliferation of estrogen receptor-positive cells. 4-HPR up-modulated expression of several differentiation markers (class 1 HLA, laminin, and beta 1 integrin chain) and down-regulated expression of molecules associated with tumor progression, including the p185/HER2 oncoprotein, the epidermal growth factor receptor, and the M(r) 67,000 laminin receptor. These data suggest that 4-HPR could exert a beneficial effect by inhibiting cell proliferation and modulating breast tumor aggressiveness.
...
PMID:Modulation of markers associated with tumor aggressiveness in human breast cancer cell lines by N-(4-hydroxyphenyl) retinamide. 754 8

For quantificative determination of ERBB2 gene amplification in archival human carcinoma specimens we have developed a rapid, non-radioactive approach, which is based on the differential polymerase chain reaction (PCR) and fluorescent DNA technique. Sequences from the ERBB2 gene and from a single-copy reference gene were amplified simultaneously by PCR, in which one of each primer pair was fluorescently labelled. PCR products were separated by polyacrylamide gel electrophoresis in an automated DNA sequencer and directly quantified after laser activation and emission scanning using appropriate software. This fluorescent differential polymerase chain reaction (fd-PCR) method was used for quantificative determination of ERBB2 gene amplification in 195 formalin-fixed, paraffin-embedded breast carcinoma tissues. ERBB2 gene amplification was found in 52 (26%) of these tumors and correlated significantly with tumor size, absence of estrogen receptor (ER) and pS2 expression, but not with absence of progesterone receptor (PR) or presence of epidermal growth factor receptor (EGF-R) expression, lymph-node metastases or grading. In univariate analysis, ERBB2 gene amplification showed no significant correlation with clinical outcome, either in the whole population or in the subgroup defined by positive axillary lymph-node metastases. However, within the node-negative subgroup, patients with ERBB2 gene amplification had significantly decreased relapse-free survival and overall survival (p < 0.05). The fd-PCR assay is a valuable tool for determination of amplification of ERBB2 gene as well as further oncogenes. In this way, more detailed information about individual tumor biology may be acquired by a routine assay.
...
PMID:ERBB2 gene amplification detected by fluorescent differential polymerase chain reaction in paraffin-embedded breast carcinoma tissues. 759 Dec 99


1 2 3 4 5 6 7 8 9 10 Next >>

---