Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0476089 (endometrial cancer)
 11,379 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tamoxifen is the most widely prescribed anti-neoplastic drug for the treatment of both localized and metastatic breast cancer. It is also the prototype for a class of drugs that are referred to as selective estrogen receptor modifiers (SERMs), most of which have both estrogenic and anti-estrogenic activity in estrogen target tissues including the breast and endometrium. The underlying mechanisms of action of SERMs in the breast and endometrium that lead to profound differences in the tissue-specific effects of tamoxifen have not yet been elucidated. We have compared the effects of tamoxifen and the pure anti-estrogen ICI 182,780 (Faslodex) in the RUCA-I hormone-responsive rat endometrial cell line in vitro and in vivo. In cell culture, RUCA-I cells responded to both estrogens and anti-estrogens, and the expression of clusterin and complement C3 mRNAs required the presence of estradiol and was repressed in the absence of estradiol or in the presence of the pure anti-estrogen ICI 182,780. Tamoxifen, on the other hand, induced both complement C3 and clusterin mRNA in the absence of estradiol and failed to repress their expression in the presence of estradiol. When grown as subcutaneous xenografts in syngeneic Da/Han rats for 5 weeks, the RUCA-I cells retained their sensitivity to estradiol, as demonstrated by significantly enhanced tumor growth in intact female rats compared with the growth in ovariectomized rats. But neither ICI 182,780 nor tamoxifen had a significant impact on tumor growth in cycling or ovariectomized animals. On the other hand, tamoxifen was potently estrogenic in metastatic lymph nodes, increasing the size of the lymph node tumors almost 6-fold over that seen in the intact cycling animals. In primary tumors, the expression of complement C3 mirrored that seen in vitro, although tamoxifen showed some agonist activity in ovariectomized animals. Tamoxifen also displayed marked agonist activity with respect to clusterin expression and enhanced clusterin mRNA levels and protein in both the primary tumors and lymph metastases in intact and ovariectomized animals. Given the recent demonstration that over-expression of clusterin increases the metastatic potential of breast cancer cells, these data may provide a mechanistic explanation for the increased incidence of endometrial cancer in postmenopausal patients treated with tamoxifen.
 ...
PMID:Tamoxifen exerts agonistic effects on clusterin and complement C3 gene expression in RUCA-I primary xenografts and metastases but not normal uterus. 1561 55

Estrogen receptor alpha (ERalpha) is a ligand-inducible transcription factor that mediates the biological effects of estrogens and antiestrogens. Many point mutations in the human ERalpha gene have been reported to be associated with breast cancer, endometrial cancer, and psychiatric diseases. However, functional analyses for most mutants with amino acid changes are still lacking. In the present study, to investigate the effects of point mutations on the function, gel-shift assays and luciferase assays were performed for eight kinds of mutated ERalpha proteins, including a single nucleotide change of C207G (N69K), G478T (G160C), T887C (L296P), A908G (K303R), C926T (S309F), A1058T (E353V), A1186G (M396V), and G1231deletion (411fsX7). The mutated ERalpha expression plasmids were constructed by site-directed mutagenesis. With gel-shift assays using in vitro translated ERalpha proteins, binding to the consensus estrogen response element (ERE) was observed for the mutated ERalpha proteins except ERalpha (G160C) and ERalpha (411fsX7), the binding of which was comparable with that of the wild type. Western blot analyses showed that ERalpha (G160C) could not be efficiently translated with the in vitro transcription/translation system and that ERalpha (411fsX7) produced a truncated protein. To investigate the transactivation potency, wild-type or mutated ERalpha expression plasmids were co-transfected with pGL3-3EREc38 reporter plasmid into human breast adenocarcinoma MDA-MB-435 cells. The concentration-response curves (10pM-100nM E2) of the mutant ERalpha proteins except ERalpha (E353V) and ERalpha (411fsX7) were similar to that of wild-type ERalpha. However, at a low level of E2 (100pM), the mutants ERalpha (N69K), ERalpha (L296P), ERalpha (S309F), and ERalpha (M396V) showed a significant decrease of transactivation compared with that of the wild-type ERalpha. The mutants ERalpha (E353V) and ERalpha (411fsX7) did not show responsiveness to E2 and antiestrogens, 4-hydroxytamoxifen (4OHT) and ICI 182,780. The mutant ERalpha (S309F) showed decreased responsiveness for the antiestrogenicity of 4OHT. In conclusion, we found that some of the naturally occurring human ERalpha mutants with amino acid changes may have an altered responsiveness to estrogen and antiestrogens.
 ...
PMID:Decreased responsiveness of naturally occurring mutants of human estrogen receptor alpha to estrogens and antiestrogens. 1671 53

Fractionation of the neutral extract of Onobrychis ebenoides (Leguminosae) yielded a new isoflavone, named ebenosin (1), in addition to the known ones, afrormosin (2), formononetin (3) and daidzein (4). Although the relative binding affinities of 1 - 4 for estrogen receptor alpha (ERalpha) were nearly comparable and matched those of 1-3 for ERbeta, that of 4 for the latter receptor was significantly higher than any of the other. Compounds 1 - 4 induced cell proliferation and gene expression in breast and endometrial cancer cells in an ER-dependent manner. Nonetheless, the rank order of induction potencies ( 4 > 3 >or= 2 >or= 1) matched better that of affinities for ERbeta ( 4 > 3 >or= 2 >or= 1) rather than ERalpha ( 4 >or= 3 >or= 2 >or= 1). While the antiestrogen ICI 182,780 could inhibit the induction of proliferation of ER-positive breast cancer cells by 1-4, it could not prevent 1 from exhibiting significant ER-independent cytotoxicity at 10 microM. By contrast, 1 was much less cytotoxic and only weakly estrogenic for ER-positive endometrial adenocarcinoma cells. In conclusion, our data suggest that the C-8 isoprenyl substituent of 1 renders it cytotoxic and/or estrogenic in a cell-dependent manner.
 ...
PMID:Estrogenic activity of isoflavonoids from Onobrychis ebenoides. 1677 31

Tamoxifen (TAM) has been used as an agent for the treatment and prevention of breast cancer. However, long-term treatment of TAM in women increases the risk of developing endometrial cancer. The secondary cancer may be due to the genotoxicity of TAM. To find safer alternatives, four selective estrogen receptor modulators (SERMs), 4-hydroxytamoxifen (4-OHTAM), toremifene (TOR), raloxifene (RAL), and ICI 182,780, were administered to rats with an equimolar dose of TAM [54 micromol/kg (20 mg/kg)/day, p.o. for 7 days]. To evaluate the genotoxicity of each SERM, the presence of bulky DNA adducts was determined by (32)P-postlabeling/polyacrylamide gel electrophoresis and (32)P-postlabeling/high-performance liquid chromatography. The formation of 7,8-dihydro-8-oxodeoxyguanosine (8-oxodG) was analyzed as a marker of typical oxidative damage, using liquid chromatography electrospray tandem mass spectrometry. Among the SERMs, bulky DNA adducts were detected in the livers of rats treated with TAM; the total amount of TAM-DNA adducts was 26.1 adducts/10(7) nucleotides. However, with a detection limit of approximately 2 adducts/10(9) nucleotides, no bulky DNA adducts were observed with 4-OHTAM, TOR, RAL, or ICI 182,780. In addition, no significant increase of hepatic 8-oxodG lesions was detected in rats treated with any of the antiestrogens. Therefore, TOR, RAL, and ICI 182,780 are likely to be less genotoxic than TAM.
 ...
PMID:Antiestrogens and the formation of DNA damage in rats: a comparison. 1678 Mar 65

Estrogen receptor-related receptor alpha (ERRalpha) was reported to compete with estrogen receptor alpha (ERalpha) in a constitutive manner as an orphan nuclear closely related to (ERalpha). To discuss the role of ERRalpha in the endometrial carcinoma cells, this study was performed. ER-responsive endometrial carcinoma cells Ishikawa and ER-nonresponse HEC-1A cells were treated with different concentration of 17beta-E2 or E2 plus ICI 182780. Semiquantitative reverse transcription-polymerase chain reaction and western blot were performed to analysis the expression of human estrogen receptor-related receptor alpha (hERRalpha). Plasmid PLXSN-hERRalpha was constructed and transfected into cells. Selected in the medium containing high-dose G418, the Ishikawa and HEC-1A cells with stable overexpression of hERRalpha were constructed and renamed as Ishikawa/hERRalpha and HEC-1A/hERRalpha, respectively. To discuss the effect of overexpression of hERRalpha in the cell biological behavior (3-[4,5-dimethylth-lazol-2yl]-2,5-diphenyltetrazolium bromid) (MTT) cell assay was performed. Estrogen downregulates ERRalpha expression in ER-positive Ishikawa cells, while upregulates the expression of ERRalpha in ER-negative HEC-1A cells. In Ishikawa cells, the downregulation of 17beta-E2 in ERRalpha expression cells could be blocked by ICI 182780. A decreasing expression of hERalpha was observed in the ER-responsive cells with overexpression of ERRalpha (Ishikawa/hERRalpha). Overexpression of hERRalpha inhibits the cell proliferation in the ERalpha-responsive Ishikawa cells and stimulated the cell proliferation in the ERalpha-nonresponsive HEC-1A cells. Function of hERRalpha depends on the expression and function of hERalpha. ER-mediated signaling might be the important factor resulting in the hormone-dependent endometrial carcinoma, whereas ERRalpha-mediated pathway might act as the vital role in hormone-independent endometrial carcinoma.
 ...
PMID:An estrogen receptor alpha-dependent regulation of estrogen receptor-related receptor alpha in the proliferation of endometrial carcinoma cells. 1701 74

In the early 1970s, a failed post-coital contraceptive, ICI 46,474, was reinvented as tamoxifen, the first targeted therapy for breast cancer. A cluster of papers published in the European Journal of Cancer described the idea of targeting tamoxifen to patients with oestrogen receptor positive tumours, and proposed the strategic value of using long-term tamoxifen therapy in an adjuvant setting with a consideration of the antitumour properties of the hydroxylated metabolites of tamoxifen. At the time, these laboratory results were slow to be embraced by the clinical community. Today, it is estimated that hundreds of thousands of breast cancer patients are alive today because of targeted long-term adjuvant tamoxifen therapy. Additionally, the first laboratory studies for the use of tamoxifen as a chemopreventive were published. Eventually, the worth of tamoxifen was tested as a chemopreventive and the drug is now known to have an excellent risk benefit ratio in high risk pre-menopausal women. Overall, the rigorous investigation of the pharmacology of tamoxifen facilitated tamoxifen's ubiquitous use for the targeted treatment of breast cancer, chemoprevention and pioneered the exploration of selective oestrogen receptor modulators (SERMs). This new concept subsequently heralded the development of raloxifene, a failed breast cancer drug, for the prevention of osteoporosis and breast cancer without the troublesome side-effect of endometrial cancer noted in post-menopausal women who take tamoxifen. Currently, the pharmaceutical industry is exploiting the SERM concept for all members of the nuclear receptor superfamily so that medicines can now be developed for diseases once thought impossible.
 ...
PMID:Tamoxifen: catalyst for the change to targeted therapy. 1806 50

During the first David A. Karnofsky Award lecture entitled "Thoughts on Chemical Therapy" in 1970, Sir Alexander Haddow commented about the dramatic regressions observed with estrogen in some breast cancers in postmenopausal women, but regrettably the mechanism was unknown. He was concerned that a cancer-specific target would remain elusive, without tests to predict response to therapy. At that time, I was conducting research for my PhD on an obscure group of estrogen derivatives called nonsteroidal antiestrogens. Antiestrogens had failed to fulfill their promise as postcoital contraceptives and were unlikely to be developed further by the pharmaceutical industry. In 1972, that perspective started to change and ICI 46,474 was subsequently reinvented as the first targeted therapy for breast cancer. The scientific strategy of targeting the estrogen receptor (ER) in the tumor, treating patients with long-term adjuvant therapy, examining active metabolites, and considering chemoprevention all translated through clinical trials to clinical practice during the next 35 years. Hundreds of thousands of women now have enhanced survivorship after their diagnosis of ER-positive breast cancer. However, it was the recognition of selective ER modulation (SERM) that created a new dimension in therapeutics. Nonsteroidal antiestrogens selectively turn on or turn off estrogen target tissues throughout the body. Patient care was immediately affected by the recognition in the laboratory that tamoxifen would potentially increase the growth of endometrial cancer during long-term adjuvant therapy. At that time, a failed breast cancer drug, keoxifene, was found to maintain bone density of rats (estrogenic action) while simultaneously preventing mammary carcinogenesis (antiestrogenic action). Perhaps a SERM used to prevent osteoporosis could simultaneously prevent breast cancer? Keoxifene was renamed raloxifene and became the first SERM for the treatment and prevention of osteoporosis as well as the prevention of breast cancer, but without an increase in endometrial cancer. There the story might have ended had the study of antihormone resistance not revealed a vulnerability of cancer cells that could be exploited in the clinic. The evolution of antihormone resistance over years of therapy reconfigures the survival mechanism of the breast cancer cell, so estrogen no longer is a survival signal but a death signal. Remarkably, remaining tumor tissue is again responsive to continuing antihormone therapy. This new discovery is currently being evaluated in clinical trials but it also solves the mystery mechanism of chemical therapy with estrogen noted by Haddow in the first Karnofsky lecture.
 ...
PMID:The 38th David A. Karnofsky lecture: the paradoxical actions of estrogen in breast cancer--survival or death? 1851 49

Selective estrogen receptor modulators (SERMs) are potentially useful in treating various endometrial disorders, including endometrial cancer, as they block some of the detrimental effects of estrogen. It remains unclear whether each SERM regulates a unique subset of genes and, if so, whether the combination of a SERM and 17beta-estradiol has an additive or synergistic effect on gene expression. We performed microarray analysis with Affymetrix Mouse Genome 430 2.0 short oligomer arrays to determine gene expression changes in uteri of ovariectomized mice treated with estradiol (low and high dose), methyl-piperidino-pyrazole (MPP), ICI 182 780, raloxifene, and combinations of high dose of estradiol with one of the SERM and dimethyl sulfoxide (DMSO) vehicle control. The nine treatments clustered into two groups, with MPP, raloxifene, and high dose of estradiol in one, and low dose of estradiol, ICI + estradiol, ICI, MPP + estradiol, and raloxifene + estradiol in the second group. Surprisingly, combining a high dose of estradiol with a SERM markedly increased (P<0.02) the number of regulated genes compared with each individual treatment. Analysis of expression for selected genes in uteri of estradiol and SERM-treated mice by quantitative (Q)RT-PCR generally supported the microarray results. For some cancer-associated genes, including Klk1, Ihh, Cdc45l, and Cdca8, administration of MPP or raloxifene with estradiol resulted in greater expression than estradiol alone (P<0.05). By contrast, ICI 182 780 suppressed more genes governing DNA replication compared with MPP and raloxifene treatments. Therefore, ICI 182 780 might be superior to MPP and raloxifene to treat estrogen-induced endometrial cancer in women.
 ...
PMID:Comparative effects of estradiol, methyl-piperidino-pyrazole, raloxifene, and ICI 182 780 on gene expression in the murine uterus. 1863 74

To examine estrogen-induced growth mechanisms of endometrial carcinoma, we investigated the estrogen-induced activation of the mitogen-activated protein kinase (MAPK) pathway and cell cycle regulators. Estradiol (E(2)) treatment at concentrations of 10(-8) M and 10(-6) M to estrogen receptor (ER)-positive endometrial carcinoma Ishikawa cells for 24 h resulted in increased cell proliferation by 20% and 28% respectively. The E(2)-induced proliferation was associated with the activation of extracellular signal-regulated kinase (MAPK)3/1 and up-regulation of cyclin D1 and E, which were suppressed by the addition of an MAP2K inhibitor (U0126) or an ER antagonist (ICI 182 780). Then, our screening for estrogen-inducible growth factors identified that IGF1 was up-regulated remarkably by E(2). Immunoprecipitation using conditioned medium of Ishikawa cells after E(2) treatment confirmed the E(2)-induced secretion of IGF1 protein. Treatment with recombinant IGF1 stimulated cell proliferation in a dose-dependent fashion, in association with MAPK3/1 phosphorylation and up-regulation of cyclin D1 and E. These IGF1-induced responses were suppressed by treatment with MAP2K inhibitor or anti-IGF1 receptor antibody. Immunohistochemical staining confirmed the expression of activated MAPK3/1 in normal proliferative phase endometria and endometrial carcinomas, indicating the involvement of this pathway in actively proliferating endometrial tissues in vivo. These findings suggest that E(2)-induced proliferation of endometrial carcinoma cells is mediated by the MAPK3/1 pathway via autocrine stimulation of IGF1.
 ...
PMID:Autocrine stimulation of IGF1 in estrogen-induced growth of endometrial carcinoma cells: involvement of the mitogen-activated protein kinase pathway followed by up-regulation of cyclin D1 and cyclin E. 1885 62

Prunella vulgaris (PV), a commonly used Chinese herb, also known as Self-heal, has a wide range of reported medicinal activities. By screening multiple herbs using the endometrial cancer cell line, ECC-1, and an alkaline phosphatase detection assay, we found that PV displayed significant antiestrogenic activity. We investigated the possible usefulness of antiestrogenic activity using both in vitro and in vivo models of endometrial function. Using the well-differentiated, hormone-responsive endometrial cell line, ECC-1, PV extract, at concentrations that were not toxic to the cells, significantly reduced alkaline phosphatase activity and cell proliferation in response to estrogen in a dose-dependent manner. The expression of CYR61, an estrogen-induced protein, was blocked in ECC-1 cells by both the antiestrogen ICI 182,780 and PV extract. Interestingly, PV extract did not appear to directly inhibit estrogen signaling. Rather, we found that its activities were probably related to an ability to function as an aryl hydrocarbon receptor (AHR) agonist in ECC-1 cells. In support of this hypothesis, we noted that PV induced CYP1A1, CYP1B1, and AHR repressor expression in a dose-dependent manner--responses that were blocked by small interfering RNA treatment to reduce AHR and specific AHR antagonists. Ovariectomized immunodeficient RAG-2/gamma(c) knockout mice implanted with human endometrial xenografts developed implants only when treated with estrogen. Mice treated with estrogen and PV tea in their drinking water had fewer and smaller xenograft implants compared with their estrogen-treated counterparts that drank only water (P < 0.05). Analysis of the resulting implants by immunohistochemistry demonstrated persistent estrogen receptor (ER), but reduced proliferation and CYR61 expression. Mouse uterine tissue weight in PV-treated mice was not different from controls, and cycle fecundity of intact C57 female mice was unaffected by PV tea treatment. PV, or Self-heal, exhibits significant antiestrogenic properties, both in vitro and in vivo. This activity is likely due to the ability of PV-activated AHR to interfere with estrogen. This herb may be useful as an adjunct for the treatment of estrogen-dependent processes like endometriosis and breast and uterine cancers. Full characterization of this herb will likely provide new insights into the crosstalk between AHR and ESR1, with potential for therapeutic applications in women.
 ...
PMID:Characterization of antiestrogenic activity of the Chinese herb, prunella vulgaris, using in vitro and in vivo (Mouse Xenograft) models. 1892 63


<< Previous 1 2 3 4 Next >>