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Sample records for tamoxifen mediated estrogen

  1. Tamoxifen

    Science.gov (United States)

    ... their age, personal medical history, and family medical history.Tamoxifen is in a class of medications known as antiestrogens. It blocks the activity of estrogen (a female hormone) in the breast. This may stop the growth ...

  2. ERBB2 regulation by Estrogen Receptor-Pax2 determines tamoxifen response

    Science.gov (United States)

    Hurtado, Antoni; Holmes, Kelly A.; Geistlinger, Timothy R.; Hutcheson, Iain R.; Nicholson, Robert I.; Brown, Myles; Jiang, Jie; Howat, William J.; Ali, Simak; Carroll, Jason S.

    2010-01-01

    Cross talk between the Estrogen Receptor (ER) and ErbB2/HER-2 pathways have long been implicated in breast cancer aetiology and drug response1, yet no direct connection at a transcriptional level has been shown. We now show that estrogen-ER and tamoxifen-ER complexes directly repress ErbB2 transcription via a cis-regulatory element within the ERBB2 gene. We implicate the Paired Box 2 gene product (Pax2), in a novel role, as a crucial mediator of ER repression of ErbB2 by the anti-cancer drug tamoxifen. We show that Pax2 and the ER co-activator AIB-1/SRC-3 compete for binding and regulation of ErbB2 transcription, the outcome of which determines tamoxifen response in breast cancer cells. The repression of ErbB2 by ER-Pax2 links these two important breast cancer subtypes and suggests that aggressive ErbB2 positive tumours can originate from ER positive luminal tumours by circumventing this repressive mechanism. These data provide mechanistic insight into the molecular basis of endocrine resistance in breast cancer. PMID:19005469

  3. Metformin enhances tamoxifen-mediated tumor growth inhibition in ER-positive breast carcinoma

    International Nuclear Information System (INIS)

    Ma, Ji; Zhang, Jian; Liu, Wenchao; Guo, Yan; Chen, Suning; Zhong, Cuiping; Xue, Yan; Zhang, Yuan; Lai, Xiaofeng; Wei, Yifang; Yu, Shentong

    2014-01-01

    Tamoxifen, an endocrine therapy drug used to treat breast cancer, is designed to interrupt estrogen signaling by blocking the estrogen receptor (ER). However, many ER-positive patients are low reactive or resistant to tamoxifen. Metformin is a widely used anti-diabetic drug with noteworthy anti-cancer effects. We investigated whether metformin has the additive effects with tamoxifen in ER-positive breast cancer therapy. The efficacy of metformin alone and in combination with tamoxifen against ER-positive breast cancer was analyzed by cell survival, DNA replication activity, plate colony formation, soft-agar, flow cytometry, immunohistochemistry, and nude mice model assays. The involved signaling pathways were detected by western blot assay. When metformin was combined with tamoxifen, the concentration of tamoxifen required for growth inhibition was substantially reduced. Moreover, metformin enhanced tamoxifen-mediated inhibition of proliferation, DNA replication activity, colony formation, soft-agar colony formation, and induction of apoptosis in ER-positive breast cancer cells. In addition, these tamoxifen-induced effects that were enhanced by metformin may be involved in the bax/bcl-2 apoptotic pathway and the AMPK/mTOR/p70S6 growth pathway. Finally, two-drug combination therapy significantly inhibited tumor growth in vivo. The present work shows that metformin and tamoxifen additively inhibited the growth and augmented the apoptosis of ER-positive breast cancer cells. It provides leads for future research on this drug combination for the treatment of ER-positive breast cancer

  4. The formation of estrogen-like tamoxifen metabolites and their influence on enzyme activity and gene expression of ADME genes.

    Science.gov (United States)

    Johänning, Janina; Kröner, Patrick; Thomas, Maria; Zanger, Ulrich M; Nörenberg, Astrid; Eichelbaum, Michel; Schwab, Matthias; Brauch, Hiltrud; Schroth, Werner; Mürdter, Thomas E

    2018-03-01

    Tamoxifen, a standard therapy for breast cancer, is metabolized to compounds with anti-estrogenic as well as estrogen-like action at the estrogen receptor. Little is known about the formation of estrogen-like metabolites and their biological impact. Thus, we characterized the estrogen-like metabolites tamoxifen bisphenol and metabolite E for their metabolic pathway and their influence on cytochrome P450 activity and ADME gene expression. The formation of tamoxifen bisphenol and metabolite E was studied in human liver microsomes and Supersomes™. Cellular metabolism and impact on CYP enzymes was analyzed in upcyte® hepatocytes. The influence of 5 µM of tamoxifen, anti-estrogenic and estrogen-like metabolites on CYP activity was measured by HPLC MS/MS and on ADME gene expression using RT-PCR analyses. Metabolite E was formed from tamoxifen by CYP2C19, 3A and 1A2 and from desmethyltamoxifen by CYP2D6, 1A2 and 3A. Tamoxifen bisphenol was mainly formed from (E)- and (Z)-metabolite E by CYP2B6 and CYP2C19, respectively. Regarding phase II metabolism, UGT2B7, 1A8 and 1A3 showed highest activity in glucuronidation of tamoxifen bisphenol and metabolite E. Anti-estrogenic metabolites (Z)-4-hydroxytamoxifen, (Z)-endoxifen and (Z)-norendoxifen inhibited the activity of CYP2C enzymes while tamoxifen bisphenol consistently induced CYPs similar to rifampicin and phenobarbital. On the transcript level, highest induction up to 5.6-fold was observed for CYP3A4 by tamoxifen, (Z)-4-hydroxytamoxifen, tamoxifen bisphenol and (E)-metabolite E. Estrogen-like tamoxifen metabolites are formed in CYP-dependent reactions and are further metabolized by glucuronidation. The induction of CYP activity by tamoxifen bisphenol and the inhibition of CYP2C enzymes by anti-estrogenic metabolites may lead to drug-drug-interactions.

  5. A study on platinum(iv) species containing an estrogen receptor modulator to reverse tamoxifen resistance of breast cancer.

    Science.gov (United States)

    Hu, Weiwei; Zhao, Jian; Hua, Wuyang; Gou, Shaohua

    2018-02-21

    Several dual-action Tam-Pt(iv) complexes derived from tamoxifen (Tam) and platinum(ii) drugs were designed and synthesized for targeting estrogen receptors (ERs) and DNA. These novel compounds not only exhibited potent cytotoxicity against breast cancer cells, but also reversed the tamoxifen resistance of TamR-MCF-7 cancer cells. Computational docking assays together with cellular uptake data demonstrated that the ER ligand portion of these conjugates plays a targeting role in ER-positive tumor cells and promotes the uptake of platinum via an estrogen receptor-mediated pathway. A study on the preliminary mechanism of the typical conjugate, complex 1, revealed that the Tam-Pt(iv) complex induced apoptosis via the mitochondrial-dependent apoptosis pathway mediated through the activation of caspase 3 and PARP proteins. These results suggested that the conjugation of estrogen receptor modulators with the platinum moiety could facilitate a selective enrichment of platinum in estrogen-positive tumors and possibly broaden the scope of ER ligand clinical use to resistant breast tumors.

  6. [Effect of the estrogen antagonist tamoxifen in the treatment of advanced mastocarcinoma (author's transl)].

    Science.gov (United States)

    Szepesi, T; Kärcher, K H

    1977-12-01

    Today the endocrin therapy of the advanced mastocarcinoma is in common use. Besides the already known therapy by estrogens, androgens, gestagens, and steroids, Tamoxifen, and estrogen antagonist, is a very promising therapeutic drug. In the presented study, Tamoxifen was submitted to a critical clinical control during a period of one year from 1st October 1975 until 1st October 1976. After a three months' treatment, a rate of 41% of objective remissions could be obtained. The criteria of success were estimated according to the scheme of Karnofsky. The average remission time is 5,5 months. By a determination of the estrogen receptors it would be possible to realize a therapeutic selection and to achieve a higher remission rate. The authors made an interesting observation, i.e. a probably immuno-stimulating effect which, however, still has to be submitted to further examinations. The side effects are described in detail and the indications are established. Its is astonishing that the subjective ameliorations, i.e. cessation of pains in case of generalized formation of metastases in the bones are much more frequent than the objective remissions. We came to the conclusion that the treatment by Tamoxifen is a valuable alternative in the therapy of the mastocarcinoma, above all in the postmenopausal period if the disease is advanced and incurable.

  7. OCT-4: a novel estrogen receptor-α collaborator that promotes tamoxifen resistance in breast cancer cells.

    Science.gov (United States)

    Bhatt, S; Stender, J D; Joshi, S; Wu, G; Katzenellenbogen, B S

    2016-11-03

    Tamoxifen has shown great success in the treatment of breast cancer; however, long-term treatment can lead to acquired tamoxifen (TOT) resistance and relapse. TOT classically antagonizes estradiol (E2) -dependent breast cancer cell growth, but exerts partial agonist/antagonist behavior on gene expression. Although both E2 and TOT treatment of breast cancer cells results in recruitment of the estrogen receptor (ER) to common and distinct genomic sites, the mechanisms and proteins underlying TOT preferential recruitment of the ER remains poorly defined. To this end, we performed in silico motif-enrichment analyses within the ER-binding peaks in response to E2 or TOT, to identify factors that would specifically recruit ER to genomic binding sites in the presence of TOT as compared to E2. Intriguingly, we found Nkx3-1 and Oct-transcription factor homodimer motifs to be enriched in TOT preferential binding sites and confirmed the critical role of Oct-3/4 (aka Oct-4) in directing ER recruitment to TOT preferential genomic binding sites, by chromatin immunoprecipitation (ChIP) analyses. Further investigation revealed Oct-4 expression to be basally repressed by Nkx3-1 in MCF-7 cells and TOT treatment appeared to elevate Nkx3-1 degradation through a p38MAPK-dependent phosphorylation of the E3 ligase, Skp2 at serine-64 residue, as observed by quantitative mass-spectrometry analyses. Consistently, Oct-4 upon induction by phospho-Ser64-Skp2-mediated proteasomal degradation of Nkx3-1, participated in ER transcriptional complexes along with p38MAPK and Skp2 in a tamoxifen-dependent manner leading to TOT-dependent gene activation and cell proliferation of the TOT-resistant MCF-7-tam r breast cancer cells. Notably, Oct-4 levels were highly elevated in MCF-7-tam r cells, and appeared critical for their TOT sensitivity in cell proliferation assays. Furthermore, overexpression of Oct-4 enhanced tumor growth in the presence of tamoxifen in mice in vivo. Collectively, our work presents

  8. Microarray Analysis on Gene Regulation by Estrogen, Progesterone and Tamoxifen in Human Endometrial Stromal Cells

    Science.gov (United States)

    Ren, Chun-E; Zhu, Xueqiong; Li, Jinping; Lyle, Christian; Dowdy, Sean; Podratz, Karl C.; Byck, David; Chen, Hai-Bin; Jiang, Shi-Wen

    2015-01-01

    Epithelial stromal cells represent a major cellular component of human uterine endometrium that is subject to tight hormonal regulation. Through cell-cell contacts and/or paracrine mechanisms, stromal cells play a significant role in the malignant transformation of epithelial cells. We isolated stromal cells from normal human endometrium and investigated the morphological and transcriptional changes induced by estrogen, progesterone and tamoxifen. We demonstrated that stromal cells express appreciable levels of estrogen and progesterone receptors and undergo different morphological changes upon hormonal stimulation. Microarray analysis indicated that both estrogen and progesterone induced dramatic alterations in a variety of genes associated with cell structure, transcription, cell cycle, and signaling. However, divergent patterns of changes, and in some genes opposite effects, were observed for the two hormones. A large number of genes are identified as novel targets for hormonal regulation. These hormone-responsive genes may be involved in normal uterine function and the development of endometrial malignancies. PMID:25782154

  9. Amplification of distant estrogen response elements deregulates target genes associated with tamoxifen resistance in breast cancer.

    Science.gov (United States)

    Hsu, Pei-Yin; Hsu, Hang-Kai; Lan, Xun; Juan, Liran; Yan, Pearlly S; Labanowska, Jadwiga; Heerema, Nyla; Hsiao, Tzu-Hung; Chiu, Yu-Chiao; Chen, Yidong; Liu, Yunlong; Li, Lang; Li, Rong; Thompson, Ian M; Nephew, Kenneth P; Sharp, Zelton D; Kirma, Nameer B; Jin, Victor X; Huang, Tim H-M

    2013-08-12

    A causal role of gene amplification in tumorigenesis is well known, whereas amplification of DNA regulatory elements as an oncogenic driver remains unclear. In this study, we integrated next-generation sequencing approaches to map distant estrogen response elements (DEREs) that remotely control the transcription of target genes through chromatin proximity. Two densely mapped DERE regions located on chromosomes 17q23 and 20q13 were frequently amplified in estrogen receptor-α-positive luminal breast cancer. These aberrantly amplified DEREs deregulated target gene expression potentially linked to cancer development and tamoxifen resistance. Progressive accumulation of DERE copies was observed in normal breast progenitor cells chronically exposed to estrogenic chemicals. These findings may extend to other DNA regulatory elements, the amplification of which can profoundly alter target transcriptome during tumorigenesis. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Microarray Analysis on Gene Regulation by Estrogen, Progesterone and Tamoxifen in Human Endometrial Stromal Cells

    Directory of Open Access Journals (Sweden)

    Chun-E Ren

    2015-03-01

    Full Text Available Epithelial stromal cells represent a major cellular component of human uterine endometrium that is subject to tight hormonal regulation. Through cell-cell contacts and/or paracrine mechanisms, stromal cells play a significant role in the malignant transformation of epithelial cells. We isolated stromal cells from normal human endometrium and investigated the morphological and transcriptional changes induced by estrogen, progesterone and tamoxifen. We demonstrated that stromal cells express appreciable levels of estrogen and progesterone receptors and undergo different morphological changes upon hormonal stimulation. Microarray analysis indicated that both estrogen and progesterone induced dramatic alterations in a variety of genes associated with cell structure, transcription, cell cycle, and signaling. However, divergent patterns of changes, and in some genes opposite effects, were observed for the two hormones. A large number of genes are identified as novel targets for hormonal regulation. These hormone-responsive genes may be involved in normal uterine function and the development of endometrial malignancies.

  11. Gene expression changes induced by estrogen and selective estrogen receptor modulators in primary-cultured human endometrial cells: signals that distinguish the human carcinogen tamoxifen

    International Nuclear Information System (INIS)

    Pole, Jessica C.M.; Gold, Leslie I.; Orton, Terry; Huby, Russell; Carmichael, Paul L.

    2005-01-01

    Tamoxifen has long been the endocrine treatment of choice for women with breast cancer and is now employed for prophylactic use in women at high risk from breast cancer. Other selective estrogen receptor modulators (SERMs), such as raloxifene, mimic some of tamoxifen's beneficial effects and, like tamoxifen, exhibit a complex mixture of organ-specific estrogen agonist and antagonistic properties. However, accompanying the positive effects of tamoxifen has been the emergence of evidence for an increased risk of endometrial cancer associated with its use. A more complete understanding of the mechanism(s) of SERM carcinogenicity and endometrial effects is therefore required. We have sought to compare and characterise the transcript profile of tamoxifen, raloxifene and the agonist estradiol in human endometrial cells. Using primary cultures of human endometria, to best emulate the in vivo responses in a manageable in vitro system, we have shown 230 significant changes in gene expression for epithelial cultures and 83 in stromal cultures, either specific to 17β-estradiol, tamoxifen or raloxifene, or changed across more than one of the treatments. Considering the transcriptome as a whole, the endometrial responses to raloxifene or tamoxifen were more similar than either drug was to 17β-estradiol. Treatment of endometrial cultures with tamoxifen resulted in the largest number of gene changes relative to control cultures and a high proportion of genes associated with regulation of gene transcription, cell-cycle control and signal transduction. Tamoxifen-specific changes that might point towards mechanisms for its proliferative response in the endometrium included changes in retinoblastoma and c-myc binding proteins, the APCL, dihydrofolate reductase (DHFR) and E2F1 genes and other transcription factors. Tamoxifen was also found to give rise to the highest number of gene expression changes common to those that characterise malignant endometria. It is anticipated that this

  12. Epidermal growth factor receptor signalling in human breast cancer cells operates parallel to estrogen receptor α signalling and results in tamoxifen insensitive proliferation

    International Nuclear Information System (INIS)

    Moerkens, Marja; Zhang, Yinghui; Wester, Lynn; Water, Bob van de; Meerman, John HN

    2014-01-01

    Tamoxifen resistance is a major problem in the treatment of estrogen receptor (ER) α -positive breast cancer patients. Although the mechanisms behind tamoxifen resistance are still not completely understood, clinical data suggests that increased expression of receptor tyrosine kinases is involved. Here, we studied the estrogen and anti-estrogen sensitivity of human breast cancer MCF7 cells that have a moderate, retroviral-mediated, ectopic expression of epidermal growth factor receptor (MCF7-EGFR). Proliferation of MCF7-EGFR and parental cells was induced by 17β-estradiol (E2), epidermal growth factor (EGF) or a combination of these. Inhibition of proliferation under these conditions was investigated with 4-hydroxy-tamoxifen (TAM) or fulvestrant at 10 -12 to 10 -6 M. Cells were lysed at different time points to determine the phosphorylation status of EGFR, MAPK 1/3 , AKT and the expression of ERα. Knockdown of target genes was established using smartpool siRNAs. Transcriptomics analysis was done 6 hr after stimulation with growth factors using Affymetrix HG-U133 PM array plates. While proliferation of parental MCF7 cells could only be induced by E2, proliferation of MCF7-EGFR cells could be induced by either E2 or EGF. Treatment with TAM or fulvestrant did significantly inhibit proliferation of MCF7-EGFR cells stimulated with E2 alone. EGF treatment of E2/TAM treated cells led to a marked cell proliferation thereby overruling the anti-estrogen-mediated inhibition of cell proliferation. Under these conditions, TAM however did still inhibit ERα- mediated transcription. While siRNA-mediated knock-down of EGFR inhibited the EGF- driven proliferation under TAM/E2/EGF condition, knock down of ERα did not. The TAM resistant cell proliferation mediated by the conditional EGFR-signaling may be dependent on the PI3K/Akt pathway but not the MEK/MAPK pathway, since a MEK inhibitor (U0126), did not block the proliferation. Transcriptomic analysis under the various E2/TAM

  13. Epidermal growth factor receptor signalling in human breast cancer cells operates parallel to estrogen receptor α signalling and results in tamoxifen insensitive proliferation.

    NARCIS (Netherlands)

    Moerkens, M.; Zhang, Y.; Wester, L.; Water, van de B.; Meerman, J.H.N.

    2014-01-01

    BACKGROUND Tamoxifen resistance is a major problem in the treatment of estrogen receptor (ER) α -positive breast cancer patients. Although the mechanisms behind tamoxifen resistance are still not completely understood, clinical data suggests that increased expression of receptor tyrosine kinases is

  14. Estrogen-mediated inactivation of FOXO3a by the G protein-coupled estrogen receptor GPER

    International Nuclear Information System (INIS)

    Zekas, Erin; Prossnitz, Eric R.

    2015-01-01

    Estrogen (17β-estradiol) promotes the survival and proliferation of breast cancer cells and its receptors represent important therapeutic targets. The cellular actions of estrogen are mediated by the nuclear estrogen receptors ERα and ERβ as well as the 7-transmembrane spanning G protein-coupled estrogen receptor (GPER). We previously reported that estrogen activates the phosphoinositide 3-kinase (PI3Kinase) pathway via GPER, resulting in phosphatidylinositol (3,4,5)-trisphosphate (PIP3) production within the nucleus of breast cancer cells; however, the mechanisms and consequences of this activity remained unclear. MCF7 breast cancer cells were transfected with GFP-fused Forkhead box O3 (FOXO3) as a reporter to assess localization in response to estrogen stimulation. Inhibitors of PI3Kinases and EGFR were employed to determine the mechanisms of estrogen-mediated FOXO3a inactivation. Receptor knockdown with siRNA and the selective GPER agonist G-1 elucidated the estrogen receptor(s) responsible for estrogen-mediated FOXO3a inactivation. The effects of selective estrogen receptor modulators and downregulators (SERMs and SERDs) on FOXO3a in MCF7 cells were also determined. Cell survival (inhibition of apoptosis) was assessed by caspase activation. In the estrogen-responsive breast cancer cell line MCF7, FOXO3a inactivation occurs on a rapid time scale as a result of GPER, but not ERα, stimulation by estrogen, established by the GPER-selective agonist G-1 and knockdown of GPER and ERα. GPER-mediated inactivation of FOXO3a is effected by the p110α catalytic subunit of PI3Kinase as a result of transactivation of the EGFR. The SERMs tamoxifen and raloxifene, as well as the SERD ICI182,780, were active in mediating FOXO3a inactivation in a GPER-dependent manner. Additionally, estrogen-and G-1-mediated stimulation of MCF7 cells results in a decrease in caspase activation under proapoptotic conditions. Our results suggest that non-genomic signaling by GPER contributes

  15. Aspirin regulation of c-myc and cyclinD1 proteins to overcome tamoxifen resistance in estrogen receptor-positive breast cancer cells.

    Science.gov (United States)

    Cheng, Ran; Liu, Ya-Jing; Cui, Jun-Wei; Yang, Man; Liu, Xiao-Ling; Li, Peng; Wang, Zhan; Zhu, Li-Zhang; Lu, Si-Yi; Zou, Li; Wu, Xiao-Qin; Li, Yu-Xia; Zhou, You; Fang, Zheng-Yu; Wei, Wei

    2017-05-02

    Tamoxifen is still the most commonly used endocrine therapy drug for estrogen receptor (ER)-positive breast cancer patients and has an excellent outcome, but tamoxifen resistance remains a great impediment to successful treatment. Recent studies have prompted an anti-tumor effect of aspirin. Here, we demonstrated that aspirin not only inhibits the growth of ER-positive breast cancer cell line MCF-7, especially when combined with tamoxifen, but also has a potential function to overcome tamoxifen resistance in MCF-7/TAM. Aspirin combined with tamoxifen can down regulate cyclinD1 and block cell cycle in G0/G1 phase. Besides, tamoxifen alone represses c-myc, progesterone receptor (PR) and cyclinD1 in MCF-7 cell line but not in MCF-7/TAM, while aspirin combined with tamoxifen can inhibit the expression of these proteins in the resistant cell line. When knocking down c-myc in MCF-7/TAM, cells become more sensitive to tamoxifen, cell cycle is blocked as well, indicating that aspirin can regulate c-myc and cyclinD1 proteins to overcome tamoxifen resistance. Our study discovered a novel role of aspirin based on its anti-tumor effect, and put forward some kinds of possible mechanisms of tamoxifen resistance in ER-positive breast cancer cells, providing a new strategy for the treatment of ER-positive breast carcinoma.

  16. The antipsychotic drug chlorpromazine enhances the cytotoxic effect of tamoxifen in tamoxifen-sensitive and tamoxifen-resistant human breast cancer cells

    DEFF Research Database (Denmark)

    Yde, Christina Westmose; Clausen, Mathias Porsmose; Bennetzen, Martin

    2009-01-01

    Tamoxifen resistance is a major clinical problem in the treatment of estrogen receptor a-positive breast tumors. It is, at present, unclear what exactly causes tamoxifen resistance. For decades, chlorpromazine has been used for treating psychotic diseases, such as schizophrenia. However, the comp......Tamoxifen resistance is a major clinical problem in the treatment of estrogen receptor a-positive breast tumors. It is, at present, unclear what exactly causes tamoxifen resistance. For decades, chlorpromazine has been used for treating psychotic diseases, such as schizophrenia. However......-sensitive breast cancer cell line, MCF-7, and in a tamoxifen-resistant cell line, established from the MCF-7 cells. Tamoxifen-sensitive and tamoxifen-resistant cells were killed equally well by combined treatment with chlorpromazine and tamoxifen. This synergistic effect could be prevented by addition of estrogen......, suggesting that chlorpromazine enhances the effect of tamoxifen through an estrogen receptor-mediated mechanism. To investigate this putative mechanism, we applied biophysical techniques to simple model membranes in the form of unilamellar liposomes of well-defined composition and found that chlorpromazine...

  17. The impact of tamoxifen on breast recurrence, cosmesis, complications, and survival in estrogen receptor-positive early-stage breast cancer

    International Nuclear Information System (INIS)

    Fowble, Barbara; Fein, Douglas A.; Hanlon, Alexandra L.; Eisenberg, Burton L.; Hoffman, John P.; Sigurdson, Elin R.; Daly, Mary B.; Goldstein, Lori J.

    1996-01-01

    Purpose: To evaluate the impact of tamoxifen on breast recurrence, cosmesis, complications, overall and cause-specific survival in women with Stage I-II breast cancer and estrogen receptor positive tumors undergoing conservative surgery and radiation. Methods and Materials: From 1982 to 1991, 491 women with estrogen receptor positive Stage I-II breast cancer underwent excisional biopsy, axillary dissection, and radiation. The median age of the patient population was 60 years with 21% < 50 years of age. The median follow-up was 5.3 years (range 0.1 to 12.8). Sixty-nine percent had T1 tumors and 83% had histologically negative axillary nodes. Reexcision was performed in 49% and the final margin of resection was negative in 64%. One hundred fifty-four patients received tamoxifen and 337 patients received no adjuvant therapy. None of the patients received adjuvant chemotherapy. Results: There were no significant differences between the two groups for age, race, clinical tumor size, histology, the use of reexcision, or median total dose to the primary. Patients who received tamoxifen were more often axillary node positive (44% tamoxifen vs. 5% no tamoxifen), and, therefore, a greater percentage received treatment to the breast and regional nodes. The tamoxifen patients less often had unknown margins of resection (9% tamoxifen vs. 22% no tamoxifen). The 5-year actuarial breast recurrence rate was 4% for the tamoxifen patients compared to 7% for patients not receiving tamoxifen (p 0.21). Tamoxifen resulted in a modest decrease in the 5-year actuarial risk of a breast recurrence in axillary node-negative patients, in those with unknown or close margins of resection, and in those who underwent a single excision. Axillary node-positive patients had a clinically significant decrease in the 5-year actuarial breast recurrence rate (21 vs. 4%; p 0.08). The 5-year actuarial rate of distant metastasis was not significantly decreased by the addition of adjuvant tamoxifen in all

  18. Novel Selective Estrogen Mimics for the Treatment of Tamoxifen-Resistant Breast Cancer

    Science.gov (United States)

    Molloy, Mary Ellen; Perez White, Bethany E.; Gherezghiher, Teshome; Michalsen, Bradley T.; Xiong, Rui; Patel, Hitisha; Zhao, Huiping; Maximov, Philipp Y.; Jordan, V. Craig; Thatcher, Gregory R. J.; Tonetti, Debra A.

    2014-01-01

    Endocrine-resistant breast cancer is a major clinical obstacle. The use of 17β-estradiol (E2) has re-emerged as a potential treatment option following exhaustive use of tamoxifen (TAM) or aromatase inhibitors although side effects have hindered its clinical usage. Protein kinase C alpha (PKCα) expression was shown to be a predictor of disease outcome for patients receiving endocrine therapy and may predict a positive response to an estrogenic treatment. Here, we have investigated the use of novel benzothiophene selective estrogen mimics (SEMs) as an alternative to E2 for the treatment of TAM-resistant breast cancer. Following in vitro characterization of SEMs, a panel of clinically relevant PKCα-expressing, TAM-resistant models were used to investigate the antitumor effects of these compounds. SEM treatment resulted in growth inhibition and apoptosis of TAM-resistant cell lines in vitro. In vivo SEM treatment induced tumor regression of TAM-resistant T47D:A18/PKCα and T47D:A18-TAM1 tumor models. T47D:A18/PKCα tumor regression was accompanied by translocation of ERα to extranuclear sites, possibly defining a mechanism through which these SEMs initiate tumor regression. SEM treatment did not stimulate growth of E2-dependent T47D:A18/neo tumors. Additionally, unlike E2 or TAM, treatment with SEMs did not stimulate uterine weight gain. These findings suggest the further development of SEMs as a feasible therapeutic strategy for the treatment of endocrine-resistant breast cancer without the side effects associated with E2. PMID:25205655

  19. Integrative analysis of miRNA and gene expression reveals regulatory networks in tamoxifen-resistant breast cancer

    DEFF Research Database (Denmark)

    Joshi, Tejal; Elias, Daniel; Stenvang, Jan

    2016-01-01

    Tamoxifen is an effective anti-estrogen treatment for patients with estrogen receptor-positive (ER+) breast cancer, however, tamoxifen resistance is frequently observed. To elucidate the underlying molecular mechanisms of tamoxifen resistance, we performed a systematic analysis of mi......+ breast cancer patients receiving adjuvant tamoxifen mono-therapy. Our results provide new insight into the molecular mechanisms of tamoxifen resistance and may form the basis for future medical intervention for the large number of women with tamoxifen-resistant ER+ breast cancer.......RNA-mediated gene regulation in three clinically-relevant tamoxifen-resistant breast cancer cell lines (TamRs) compared to their parental tamoxifen-sensitive cell line. Alterations in the expression of 131 miRNAs in tamoxifen-resistant vs. parental cell lines were identified, 22 of which were common to all Tam...

  20. Tamoxifen-Containing Eye Drops Successfully Trigger Cre-Mediated Recombination in the Entire Eye.

    Science.gov (United States)

    Schlecht, Anja; Leimbeck, Sarah V; Tamm, Ernst R; Braunger, Barbara M

    2016-01-01

    Embryonic lethality in mice with targeted gene deletion is a major issue that can be circumvented by using Cre-loxP-based animal models. Various inducible Cre systems are available, e.g. such that are activated following tamoxifen treatment, and allow deletion of a specific target gene at any desired time point during the life span of the animal. In this study, we describe the efficiency of topical tamoxifen administration by eye drops using a Cre- reporter mouse strain (R26R). We report that tamoxifen-responsive CAGGCre-ER (TM) mice show a robust Cre- mediated recombination throughout the entire eye.

  1. Gene expression signatures that predict outcome of tamoxifen-treated estrogen receptor-positive, high-risk, primary breast cancer patients

    DEFF Research Database (Denmark)

    Lyng, Maria B; Lænkholm, Anne-Vibeke; Tan, Qihua

    2013-01-01

    BACKGROUND: Tamoxifen significantly improves outcome for estrogen receptor-positive (ER+) breast cancer, but the 15-year recurrence rate remains 30%. The aim of this study was to identify gene profiles that accurately predicted the outcome of ER+ breast cancer patients who received adjuvant...... Tamoxifen mono-therapy. METHODOLOGY/PRINCIPAL FINDINGS: Post-menopausal breast cancer patients diagnosed no later than 2002, being ER+ as defined by >1% IHC staining and having a frozen tumor sample with >50% tumor content were included. Tumor samples from 108 patients treated with adjuvant Tamoxifen were...

  2. Prognostic and predictive importance of the estrogen receptor coactivator AIB1 in a randomized trial comparing adjuvant letrozole and tamoxifen therapy in postmenopausal breast cancer

    DEFF Research Database (Denmark)

    Alkner, S; Jensen, M-B; Rasmussen, B B

    2017-01-01

    PURPOSE: To evaluate the estrogen receptor coactivator amplified in breast cancer 1 (AIB1) as a prognostic marker, as well as a predictive marker for response to adjuvant tamoxifen and/or aromatase inhibitors, in early estrogen receptor-positive breast cancer. METHOD: AIB1 was analyzed...... with immunohistochemistry in tissue microarrays of the Danish subcohort (N = 1396) of the International Breast Cancer Study Group's trial BIG 1-98 (randomization between adjuvant tamoxifen versus letrozole versus the sequence of the two drugs). RESULTS: Forty-six percent of the tumors had a high AIB1 expression. In line...... with previous studies, AIB1 correlated to a more aggressive tumor-phenotype (HER2 amplification and a high malignancy grade). High AIB1 also correlated to higher estrogen receptor expression (80-100 vs. 1-79%), and ductal histological type. High AIB1 expression was associated with a poor disease-free survival...

  3. Raptor localization predicts prognosis and tamoxifen response in estrogen receptor-positive breast cancer.

    Science.gov (United States)

    Bostner, Josefine; Alayev, Anya; Berman, Adi Y; Fornander, Tommy; Nordenskjöld, Bo; Holz, Marina K; Stål, Olle

    2018-02-01

    Deregulated PI3K/mTOR signals can promote the growth of breast cancer and contribute to endocrine treatment resistance. This report aims to investigate raptor and its intracellular localization to further understand its role in ER-positive breast cancer. Raptor protein expression was evaluated by immunohistochemistry in 756 primary breast tumors from postmenopausal patients randomized to tamoxifen or no tamoxifen. In vitro, the MCF7 breast cancer cell line and tamoxifen-resistant MCF7 cells were studied to track the raptor signaling changes upon resistance, and raptor localization in ERα-positive cell lines was compared with that in ERα-negative cell lines. Raptor protein expression in the nucleus was high in ER/PgR-positive and HER2-negative tumors with low grade, features associated with the luminal A subtype. Presence of raptor in the nucleus was connected with ERα signaling, here shown by a coupled increase of ERα phosphorylation at S167 and S305 with accumulation of nuclear raptor. In addition, the expression of ERα-activated gene products correlated with nuclear raptor. Similarly, in vitro we observed raptor in the nucleus of ERα-positive, but not of ER-negative cells. Interestingly, raptor localized to the nucleus could still be seen in tamoxifen-resistant MCF7 cells. The clinical benefit from tamoxifen was inversely associated with an increase of nuclear raptor. High cytoplasmic raptor expression indicated worse prognosis on long-term follow-up. We present a connection between raptor localization to the nucleus and ERα-positive breast cancer, suggesting raptor as a player in stimulating the growth of the luminal A subtype and a possible target along with endocrine treatment.

  4. Profiling of gene expression regulated by 17β-estradiol and tamoxifen in estrogen receptor-positive and estrogen receptor-negative human breast cancer cell lines

    Directory of Open Access Journals (Sweden)

    Rangel N

    2017-09-01

    Full Text Available Nelson Rangel,1,2 Victoria E Villegas,2 Milena Rondón-Lagos3 1Department of Medical Sciences, University of Turin, Turin, Italy; 2Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá, Colombia; 3School of Biological Sciences, Universidad Pedagógica y Tecnológica de Colombia, Tunja, Colombia Abstract: One area of great importance in breast cancer (BC research is the study of gene expression regulated by both estrogenic and antiestrogenic agents. Although many studies have been performed in this area, most of them have only addressed the effects of 17β-estradiol (E2 and tamoxifen (TAM on MCF7 cells. This study aimed to determine the effect of low doses of E2 and TAM on the expression levels of 84 key genes, which are commonly involved in breast carcinogenesis, in four BC cell lines differentially expressing estrogen receptor (ER α and HER2 (MCF7, T47D, BT474, and SKBR3. The results allowed us to determine the expression patterns modulated by E2 and TAM in ERα+ and ERα− cell lines, as well as to identify differences in expression patterns. Although the MCF7 cell line is the most frequently used model to determine gene expression profiles in response to E2 and TAM, the changes in gene expression patterns identified in ERα+ and ERα− cell lines could reflect distinctive properties of these cells. Our results could provide important markers to be validated in BC patient samples, and subsequently used for predicting the outcome in ERα+ and ERα− tumors after TAM or hormonal therapy. Considering that BC is a molecularly heterogeneous disease, it is important to understand how well, and which cell lines, best model that diversity. Keywords: breast cancer, cell lines, 17β-estradiol, tamoxifen, ERα+, ERα−, qPCR

  5. A comparison of survival outcomes and side effects of toremifene or tamoxifen therapy in premenopausal estrogen and progesterone receptor positive breast cancer patients: a retrospective cohort study

    International Nuclear Information System (INIS)

    Gu, Ran; Long, Meijun; Chen, Kai; Chen, Lili; Xiao, Qiaozhen; Wu, Mei; Song, Erwei; Su, Fengxi; Jia, Weijuan; Zeng, Yunjie; Rao, Nanyan; Hu, Yue; Li, Shunrong; Wu, Jiannan; Jin, Liang; Chen, Lijuan

    2012-01-01

    In premenopausal women, endocrine adjuvant therapy for breast cancer primarily consists of tamoxifen alone or with ovarian suppressive strategies. Toremifene is a chlorinated derivative of tamoxifen, but with a superior risk-benefit profile. In this retrospective study, we sought to establish the role of toremifene as an endocrine therapy for premenopausal patients with estrogen and/or progesterone receptor positive breast cancer besides tamoxifen. Patients with early invasive breast cancer were selected from the breast tumor registries at the Sun Yat-Sen Memorial Hospital (China). Premenopausal patients with endocrine responsive breast cancer who underwent standard therapy and adjuvant therapy with toremifene or tamoxifen were considered eligible. Patients with breast sarcoma, carcinosarcoma, concurrent contralateral primary breast cancer, or with distant metastases at diagnosis, or those who had not undergone surgery and endocrine therapy were ineligible. Overall survival and recurrence-free survival were the primary outcomes measured. Toxicity data was also collected and compared between the two groups. Of the 810 patients reviewed, 452 patients were analyzed in the study: 240 received tamoxifen and 212 received toremifene. The median and mean follow up times were 50.8 and 57.3 months, respectively. Toremifene and tamoxifen yielded similar overall survival values, with 5-year overall survival rates of 100% and 98.4%, respectively (p = 0.087). However, recurrence-free survival was significantly better in the toremifene group than in the tamoxifen group (p = 0.022). Multivariate analysis showed that recurrence-free survival improved independently with toremifene (HR = 0.385, 95% CI = 0.154-0.961; p = 0.041). Toxicity was similar in the two treatment groups with no women experiencing severe complications, other than hot flashes, which was more frequent in the toremifene patients (p = 0.049). No patients developed endometrial cancer. Toremifene may be a valid and

  6. Effects of SULT1A1 Copy Number Variation on Estrogen Concentration and Tamoxifen-Associated Adverse Drug Reactions in Premenopausal Thai Breast Cancer Patients: A Preliminary Study.

    Science.gov (United States)

    Charoenchokthavee, Wanaporn; Ayudhya, Duangchit Panomvana Na; Sriuranpong, Virote; Areepium, Nutthada

    2016-01-01

    Tamoxifen is a pharmacological estrogen inhibitor that binds to the estrogen receptor (ER) in breast cells. However, it shows an estrogenic effect in other organs, which causes adverse drug reactions (ADRs). The sulfotransferase 1A1 (SULT1A1) enzyme encoded by the SULT1A1 gene is involved in estrogen metabolism. Previous research has suggested that the SULT1A1 copy number is linked with the plasma estradiol (E2) concentration. Here, a total of 34 premenopausal breast cancer patients, selected from the Thai Tamoxifen (TTAM) Project, were screened for their SULT1A1 copy number, plasma E2 concentration and ADRs. The mean age was 44.3±11.1 years, and they were subtyped as ER+/ progesterone receptor (PR) + (28 patients), ER+/ PR- (5 patients) and ER-/PR- (1 patient). Three patients reported ADRs, which were irregular menstruation (2 patients) and vaginal discharge (1 patient). Most (33) patients had two SULT1A1 copies, with one patient having three copies. The median plasma E2 concentration was 1,575.6 (IQR 865.4) pg/ml. Patients with ADRs had significantly higher plasma E2 concentrations than those patients without ADRs (p = 0.014). The plasma E2 concentration was numerically higher in the patient with three SULT1A1 copies, but this lacked statistical significance.

  7. The impact of tamoxifen on breast recurrence, cosmesis, complications, and survival in estrogen receptor positive early stage breast cancer

    International Nuclear Information System (INIS)

    Fowble, B.; Fein, D.A.; Hanlon, A.L.; Eisenberg, B.L.; Hoffman, J.P.; Sigurdson, E.R.; Daly, M.B.; Goldstein, L.J.

    1995-01-01

    Purpose: In the NSABP B14 trial evaluating tamoxifen (tam) in axillary node negative, estrogen receptor positive tumors fewer breast recurrences were observed in patients treated with conservative surgery and radiation who received tam compared to the observation arm. An additional series, however, has suggested that tam adversely impacts on the cosmetic result. To further address these issues we compared the outcome of estrogen receptor positive tumors treated with conservative surgery and radiation with or without tam. Materials and Methods: From 1982 to 1991, 491 women with estrogen receptor positive stage I-II breast cancer underwent excisional biopsy, axillary dissection and radiation. The median age of the patient population was 60 years (range 39-85). The median followup was 5.3 years (range .1-12.8). 69% had T1 tumors and 83% had histologically negative axillary nodes. Reexcision was performed in 49%. The final margin of resection was negative in 64%, unknown in 18%, and close or positive in 19%. None of the patients received adjuvant chemotherapy. 154 patients received tam and 337 received no adjuvant therapy. Patients who received tam were more often axillary node positive (44% tam vs 5% no tam) and less often had unknown margins (9% tam vs 22% no tam). There were no significant differences for the 2 groups for median age, primary tumor size, histology, race, or use of reexcision. Results: The 5 yr act rate of breast recurrence was 4% for the tam patients compared to 7% for patients not receiving tam (p=.21). At 8 yrs, the breast recurrence rates were 4% for the tam patients compared to 11% for the no tam patients (p=.05). However, at 9 years the rates were 17% tam vs 14% no tam (p=.21). The benefit from tam in terms of a decreased 5 year actuarial breast recurrence rate was most evident for patients who did not have a reexcision (3% tam vs 10% no tam, p=.15), had unknown margins (7% tam vs 13% no tam, p=.37) or close margins (0% tam vs 11% no tam, p=.34

  8. Do microRNAs Mediate Estrogen-Dependent Repression of Genes

    National Research Council Canada - National Science Library

    Nakshatri, Harikrishna; Collins, Nikail R

    2008-01-01

    Estrogen receptor alpha (ERa) mediates transcriptional effects of estrogen. Estrogen inducible proteins c-Myc and E2F family are required for optimal ERa activity and secondary estrogen response, respectively...

  9. ROLE OF MORPHOLOGICAL AND GENETIC STRUCTURAL CHARACTERISTICS OF ESTROGEN RECEPTOR ALPHA IN THE DEVELOPMENT OF RESISTANCE TO ENDOCRINOTHERAPY WITH TAMOXIFEN IN PATIENTS WITH LUMINAL BREAST CANCER

    Directory of Open Access Journals (Sweden)

    Е. М. Slonimskaya

    2014-01-01

    Full Text Available Hormone therapy with tamoxifen is the commonly used treatment for luminal breast cancer. However, it appears to be ineffective in 20–40 % of cases and the possible reasons of this failure are related to the features of distribution and structure of estrogen receptor alpha (ERα in tumor tissue. Realization of the therapeutic effect of tamoxifen is carried out by blocking the activation center of AF-2 receptor. The change in the functional state of this receptor resulted from single-nucleotide polymorphisms coding 2228480 (G/A in exon 8 of ERα gene is considered as a possible cause of treatment failure with tamoxifen.The purpose of the study was to analyze the relationship between the ERα expression and polymorphic variants in exon 8 of the ERα gene and the efficacy of tamoxifen in patientswith luminal breast cancer.Material and methods: The study included 97 patients with stage T1–2N0–1M0 luminal breast cancer, who received adjuvant chemotherapy with tamoxifen. The follow-up ranged from 24 to 130 months. Long-term treatment outcomes were assessed upon the progression of the disease with the evidence of distant metastases. In tumor tissue samples, the ERα expression was studied using the immunohistochemical method. The values of the ERα expression intensity as well as the character of ERα distribution were assessed. Polymorphic variants of exon 8 of the ERα gene were studied using real-time PCR.Results. The heterogeneous distribution of ERα gene was observed in 86.5 % cases with diseases progression and in 58.3 % of cases with favorable disease outcome (р=0.0072; χ2 =7.22. Mutation of rs2228480 (G/A in exon 8 of the ERα gene was observed in 19.4 % of cases. Mutations were not noted in tumor cells with homogenous distribution of the ERα gene and mutations were found in 25.7 % (р=0.014; χ2 =6.09 in heterogeneous distribution. Mutation in exon 8 of the ERα gene was shown to occur more often in patients with disease progression

  10. Investigating the Regulation of Estrogen Receptor-Mediated Transcription

    National Research Council Canada - National Science Library

    Thackray, Varykina

    2002-01-01

    ...-mediated regulation of specific target genes are still lacking. We have developed an estrogen responsive system in the fruit fly, Drosophila melanogaster in order to explore the functional interactions between ER and other cellular proteins...

  11. Investigating the Regulation of Estrogen Receptor-Mediated Transcription

    National Research Council Canada - National Science Library

    Thackray, Varykina

    2001-01-01

    ...-mediated regulation of specific target genes are still lacking. We have developed an estrogen responsive system in the fruit fly, Drosophila melanogaster in order to explore the functional interactions between ER and other cellular proteins...

  12. Optimized axolotl (Ambystoma mexicanum) husbandry, breeding, metamorphosis, transgenesis and tamoxifen-mediated recombination.

    Science.gov (United States)

    Khattak, Shahryar; Murawala, Prayag; Andreas, Heino; Kappert, Verena; Schuez, Maritta; Sandoval-Guzmán, Tatiana; Crawford, Karen; Tanaka, Elly M

    2014-03-01

    The axolotl (Mexican salamander, Ambystoma mexicanum) has become a very useful model organism for studying limb and spinal cord regeneration because of its high regenerative capacity. Here we present a protocol for successfully mating and breeding axolotls in the laboratory throughout the year, for metamorphosing axolotls by a single i.p. injection and for axolotl transgenesis using I-SceI meganuclease and the mini Tol2 transposon system. Tol2-mediated transgenesis provides different features and advantages compared with I-SceI-mediated transgenesis, and it can result in more than 30% of animals expressing the transgene throughout their bodies so that they can be directly used for experimentation. By using Tol2-mediated transgenesis, experiments can be performed within weeks (e.g., 5-6 weeks for obtaining 2-3-cm-long larvae) without the need to establish germline transgenic lines (which take 12-18 months). In addition, we describe here tamoxifen-induced Cre-mediated recombination in transgenic axolotls.

  13. Tamoxifen enhances erlotinib-induced cytotoxicity through down-regulating AKT-mediated thymidine phosphorylase expression in human non-small-cell lung cancer cells.

    Science.gov (United States)

    Ko, Jen-Chung; Chiu, Hsien-Chun; Syu, Jhan-Jhang; Jian, Yi-Jun; Chen, Chien-Yu; Jian, Yun-Ting; Huang, Yi-Jhen; Wo, Ting-Yu; Lin, Yun-Wei

    2014-03-01

    Tamoxifen is a triphenylethylene nonsteroidal estrogen receptor (ER) antagonist used worldwide as an adjuvant hormone therapeutic agent in the treatment of breast cancer. However, the molecular mechanism of tamoxifen-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Thymidine phosphorylase (TP) is an enzyme of the pyrimidine salvage pathway which is upregulated in cancers. In this study, tamoxifen treatment inhibited cell survival in two NSCLC cells, H520 and H1975. Treatment with tamoxifen decreased TP mRNA and protein levels through AKT inactivation. Furthermore, expression of constitutively active AKT (AKT-CA) vectors significantly rescued the decreased TP protein and mRNA levels in tamoxifen-treated NSCLC cells. In contrast, combination treatment with PI3K inhibitors (LY294002 or wortmannin) and tamoxifen further decreased the TP expression and cell viability of NSCLC cells. Knocking down TP expression by transfection with small interfering RNA of TP enhanced the cytotoxicity and cell growth inhibition of tamoxifen. Erlotinib (Tarceva, OSI-774), an orally available small molecular inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, is approved for clinical treatment of NSCLC. Compared to a single agent alone, tamoxifen combined with erlotinib resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells, accompanied with reduced activation of phospho-AKT and phospho-ERK1/2, and reduced TP protein levels. These findings may have implications for the rational design of future drug regimens incorporating tamoxifen and erlotinib for the treatment of NSCLC. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Implications of astrocytes in mediating the protective effects of Selective Estrogen Receptor Modulators upon brain damage

    Directory of Open Access Journals (Sweden)

    George E. Barreto

    2015-04-01

    Full Text Available Selective Estrogen Receptor Modulators (SERMs are steroidal or non-steroidal compounds that are already used in clinical practice for the treatment of breast cancer, osteoporosis and menopausal symptoms. While SERMs actions in the breast, bone, and uterus have been well characterized, their actions in the brain are less well understood. Previous works have demonstrated the beneficial effects of SERMs in different chronic neurodegenerative diseases like Alzheimer, Parkinson’s disease and Multiple sclerosis, as well as acute degeneration as stroke and traumatic brain injury. Moreover, these compounds exhibit similar protective actions as those of estradiol in the Central Nervous System, overt any secondary effect. For these reasons, in the past few years, there has been a growing interest in the neuroprotective effects exerted directly or indirectly by SERMs in the SNC. In this context, astrocytes play an important role in the maintenance of brain metabolism, and antioxidant support to neurons, thus indicating that better protection of astrocytes are an important asset targeting neuronal protection. Moreover, various clinical and experimental studies have reported that astrocytes are essential for the neuroprotective effects of SERMs during neuronal injuries, as these cells express different estrogen receptors in cell membrane, demonstrating that part of SERMs effects upon injury may be mediated by astrocytes. The present work highlights the current evidence on the protective mechanisms of SERMs, such as tamoxifen and raloxifene, in the SNC, and their modulation of astrocytic properties as promising therapeutic targets during brain damage.

  15. Src Is a Potential Therapeutic Target in Endocrine-Resistant Breast Cancer Exhibiting Low Estrogen Receptor-Mediated Transactivation.

    Science.gov (United States)

    Guest, Stephanie K; Ribas, Ricardo; Pancholi, Sunil; Nikitorowicz-Buniak, Joanna; Simigdala, Nikiana; Dowsett, Mitch; Johnston, Stephen R; Martin, Lesley-Ann

    2016-01-01

    Despite the effectiveness of endocrine therapies in estrogen receptor positive (ER+) breast cancer, approximately 40% of patients relapse. Previously, we identified the Focal-adhesion kinase canonical pathway as a major contributor of resistance to estrogen deprivation and cellular-sarcoma kinase (c-src) as a dominant gene in this pathway. Dasatinib, a pan-src inhibitor, has recently been used in clinical trials to treat ER+ patients but has shown mixed success. In the following study, using isogenic cell line models, we provide a potential explanation for these findings and suggest a sub-group that may benefit. A panel of isogenic cell lines modelling resistance to aromatase inhibitors (LTED) and tamoxifen (TAMR) were assessed for response to dasatinib ± endocrine therapy. Dasatinib caused a dose-dependent decrease in proliferation in MCF7-TAMR cells and resensitized them to tamoxifen and fulvestrant but not in HCC1428-TAMR. In contrast, in estrogen-deprived conditions, dasatinib increased the proliferation rate of parental-MCF7 cells and had no effect on MCF7-LTED or HCC1428-LTED. Treatment with dasatinib caused a decrease in src-phosphorylation and inhibition of downstream pathways, including AKT and ERK1/2 in all cell lines tested, but only the MCF7-TAMR showed a concomitant decrease in markers of cell cycle progression. Inhibition of src also caused a significant decrease in cell migration in both MCF7-LTED and MCF7-TAMR cells. Finally, we showed that, in MCF7-TAMR cells, in contrast to tamoxifen sensitive cell lines, ER is expressed throughout the cell rather than being restricted to the nucleus and that treatment with dasatinib resulted in nuclear shuttling of ER, which was associated with an increase in ER-mediated transcription. These data suggest that src has differential effects in endocrine-resistant cell lines, particularly in tamoxifen resistant models, with low ER genomic activity, providing further evidence of the importance of patient selection

  16. Relationship between intratumoral expression of genes coding for xenobiotic-metabolizing enzymes and benefit from adjuvant tamoxifen in estrogen receptor alpha-positive postmenopausal breast carcinoma

    International Nuclear Information System (INIS)

    Bièche, Ivan; Girault, Igor; Urbain, Estelle; Tozlu, Sengül; Lidereau, Rosette

    2004-01-01

    Little is known of the function and clinical significance of intratumoral dysregulation of xenobiotic-metabolizing enzyme expression in breast cancer. One molecular mechanism proposed to explain tamoxifen resistance is altered tamoxifen metabolism and bioavailability. To test this hypothesis, we used real-time quantitative RT-PCR to quantify the mRNA expression of a large panel of genes coding for the major xenobiotic-metabolizing enzymes (12 phase I enzymes, 12 phase II enzymes and three members of the ABC transporter family) in a small series of normal breast (and liver) tissues, and in estrogen receptor alpha (ERα)-negative and ERα-positive breast tumors. Relevant genes were further investigated in a well-defined cohort of 97 ERα-positive postmenopausal breast cancer patients treated with primary surgery followed by adjuvant tamoxifen alone. Seven of the 27 genes showed very weak or undetectable expression in both normal and tumoral breast tissues. Among the 20 remaining genes, seven genes (CYP2A6, CYP2B6, FMO5, NAT1, SULT2B1, GSTM3 and ABCC11) showed significantly higher mRNA levels in ERα-positive breast tumors than in normal breast tissue, or showed higher mRNA levels in ERα-positive breast tumors than in ERα-negative breast tumors. In the 97 ERα-positive breast tumor series, most alterations of these seven genes corresponded to upregulations as compared with normal breast tissue, with an incidence ranging from 25% (CYP2A6) to 79% (NAT1). Downregulation was rare. CYP2A6, CYP2B6, FMO5 and NAT1 emerged as new putative ERα-responsive genes in human breast cancer. Relapse-free survival was longer among patients with FMO5-overexpressing tumors or NAT1-overexpressing tumors (P = 0.0066 and P = 0.000052, respectively), but only NAT1 status retained prognostic significance in Cox multivariate regression analysis (P = 0.0013). Taken together, these data point to a role of genes coding for xenobiotic-metabolizing enzymes in breast tumorigenesis, NAT1 being an

  17. Activation of estrogen response elements is mediated both via estrogen and muscle contractions in rat skeletal muscle myotubes

    DEFF Research Database (Denmark)

    Wiik, A.; Hellsten, Ylva; Berthelson, P.

    2009-01-01

    then differentiated into myotubes and subjected to either estrogen or electrical stimulation. Activation of the ERE sequence was determined by measurement of luciferase activity. The results show that both ERalpha and ERbeta are expressed in myotubes from rats. Both estrogen stimulation and muscle contraction......The aim of the present study was to investigate the activation of estrogen response elements (EREs) by estrogen and muscle contractions in rat myotubes in culture and to assess whether the activation is dependent on the estrogen receptors (ERs). In addition, the effect of estrogen and contraction...... increased (P muscle contraction. Use of ER antagonists showed that, whereas the estrogen-induced transactivation is mediated via ERs, the effect of muscle contraction...

  18. Nongenomic mechanisms of physiological estrogen-mediated dopamine efflux

    Directory of Open Access Journals (Sweden)

    Watson Cheryl S

    2009-06-01

    Full Text Available Abstract Background Neurological diseases and neuropsychiatric disorders that vary depending on female life stages suggest that sex hormones may influence the function of neurotransmitter regulatory machinery such as the dopamine transporter (DAT. Results In this study we tested the rapid nongenomic effects of several physiological estrogens [estradiol (E2, estrone (E1, and estriol (E3] on dopamine efflux via the DAT in a non-transfected, NGF-differentiated, rat pheochromocytoma (PC12 cell model that expresses membrane estrogen receptors (ERs α, β, and GPR30. We examined kinase, ionic, and physical interaction mechanisms involved in estrogenic regulation of the DAT function. E2-mediated dopamine efflux is DAT-specific and not dependent on extracellular Ca2+-mediated exocytotic release from vesicular monoamine transporter vesicles (VMATs. Using kinase inhibitors we also showed that E2-mediated dopamine efflux is dependent on protein kinase C and MEK activation, but not on PI3K or protein kinase A. In plasma membrane there are ligand-independent associations of ERα and ERβ (but not GPR30 with DAT. Conditions which cause efflux (a 9 min 10-9 M E2 treatment cause trafficking of ERα (stimulatory to the plasma membrane and trafficking of ERβ (inhibitory away from the plasma membrane. In contrast, E1 and E3 can inhibit efflux with a nonmonotonic dose pattern, and cause DAT to leave the plasma membrane. Conclusion Such mechanisms explain how gender biases in some DAT-dependent diseases can occur.

  19. Risk of Parkinson's disease after tamoxifen treatment

    Directory of Open Access Journals (Sweden)

    Destefano Anita L

    2010-04-01

    Full Text Available Abstract Background Women have a reduced risk of developing Parkinson's disease (PD compared with age-matched men. Neuro-protective effects of estrogen potentially explain this difference. Tamoxifen, commonly used in breast cancer treatment, may interfere with the protective effects of estrogen and increase risk of PD. We compared the rate of PD in Danish breast cancer patients treated with tamoxifen to the rate among those not treated with tamoxifen. Methods A cohort of 15,419 breast cancer patients identified from the Danish Breast Cancer Collaborative Group database was linked to the National Registry of Patients to identify PD diagnoses. Overall risk and rate of PD following identification into the study was compared between patients treated with tamoxifen as adjuvant hormonal therapy and patients not receiving tamoxifen. Time-dependent effects of tamoxifen treatment on PD rate were examined to estimate the likely induction period for tamoxifen. Results In total, 35 cases of PD were identified among the 15,419 breast cancer patients. No overall effect of tamoxifen on rate of PD was observed (HR = 1.3, 95% CI: 0.64-2.5, but a PD hazard ratio of 5.1 (95% CI: 1.0-25 was seen four to six years following initiation of tamoxifen treatment. Conclusions These results provide evidence that the neuro-protective properties of estrogen against PD occurrence may be disrupted by tamoxifen therapy. Tamoxifen treatments may be associated with an increased rate of PD; however these effects act after four years, are of limited duration, and the adverse effect is overwhelmed by the protection against breast recurrence conferred by tamoxifen therapy.

  20. Long-Term Data from 20 Trials Confirm Tamoxifen's Long-Lasting Benefit

    Science.gov (United States)

    Women with estrogen receptor-positive breast cancer who received about 5 years of adjuvant tamoxifen had a lower risk of recurrence in the 15 years after treatment than women who did not receive tamoxifen.

  1. The role of estrogen receptor alpha in mediating chemoresistance in breast cancer cells

    Directory of Open Access Journals (Sweden)

    Jiang Zhinong

    2012-05-01

    Full Text Available Abstract Introduction Previous studies suggested that estrogen receptor alpha (ERα plays an important role in the chemoresistance of breast cancers. However, large random trials failed to demonstrate any benefit of the concurrent estrogen antagonist tamoxifen on the chemotherapy efficacy. Thus, in the present study, the importance of the role of ERα in the chemoresistance of breast cancer cells was investigated. Methods The ERα-transfected Bcap37 cells and natural ERα-positive T47D breast cancer cells were treated using chemotherapeutic agents with or without 17-beta estradiol (E2 pretreatment. Their viabilities were assessed using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assays. The dead cell rates were determined using propidium iodide dye exclusion tests, and the expression levels of Bcl-2 and Bax were detected through Western blot analysis. The effects of E2 on the growth of breast cancer cells were also determined via cell growth curve and cell cycle analysis. Results ERα activation by E2 increased the sensitivity of natural ERα-positive T47D breast cancer cells to chemotherapeutic agents. However, the increase in ERα expression in ERα-negative Bcap37 breast cancer cells also significantly increased their resistance. These phenomena cannot be explained by asserting that ERα mediated the chemoresistance of breast cancer cells by regulating the expression of Bcl-2 and Bax. Our findings show that ERα activation upregulated the expression of Bcl-2 in natural ERα-positive T47D breast cancer cells, whereas ERα activation by E2 downregulated and upregulated the Bcl-2 and Bax expression levels, respectively, in ERα-transfected Bcap37 cells. This phenomenon was due to the influence of ERα on the growth of breast cancer cells. Specifically, ERα activation enhanced the growth of natural ERα-positive breast cancer cells and thus increased their sensitivity to chemotherapeutic agents. However, ERα activation also

  2. Tamoxifen and ovarian function.

    Directory of Open Access Journals (Sweden)

    Martine Berliere

    Full Text Available BACKGROUND: Some studies suggest that the clinical parameter "amenorrhea" is insufficient to define the menopausal status of women treated with chemotherapy or tamoxifen. In this study, we investigated and compared the ovarian function defined either by clinical or biological parameters in pre-menopausal breast cancer patients treated with tamoxifen administered as adjuvant therapy. MATERIALS AND METHODS: Between 1999 and 2003, 138 premenopausal patients consecutively treated for early breast cancer were included. Sixty-eight received tamoxifen in monotherapy as the only adjuvant systemic treatment (Group I and 70 were treated with tamoxifen after adjuvant chemotherapy (Group II. All patients had a confirmed premenopausal status based on clinical parameters and hormonal values at study entry. They were followed prospectively every 3 months for 3 years: menses data, physical examination and blood tests (LH, FSH, 17-beta-estradiol. Vaginal ultrasonography was carried out every 6 months. After 3 years, prospective evaluation was completed and monitoring of ovarian function was performed as usual in our institution (1x/year. All data were retrospectively evaluated in 2011. RESULTS: Three patients were excluded from the study in group I and 2 were excluded in group II. Patients were divided into 4 subgroups according to clinical data, i.e. menses patterns. These patterns were assessed by questionnaires. a: Regular menses (>10 cycles/year b: Oligomenorrhea (5 to 9 cycles/year c: Severe oligomenorrhea (1 to 4 cycles/year d: Complete amenorrhea Estrogen levels did not appear to have any impact on disease-free survival rates after 3 or 8 years. FSH values were also documented and analyzed. They exhibited the same profile as estradiol values. CONCLUSIONS: Amenorrhea is an insufficient parameter to define menopausal status in patients receiving tamoxifen. Low estradiol levels must be coupled with other biological parameters to characterize endocrine status

  3. Changes in the transcriptome of the human endometrial Ishikawa cancer cell line induced by estrogen, progesterone, tamoxifen, and mifepristone (RU486 as detected by RNA-sequencing.

    Directory of Open Access Journals (Sweden)

    Karin Tamm-Rosenstein

    Full Text Available BACKGROUND: Estrogen (E2 and progesterone (P4 are key players in the maturation of the human endometrium. The corresponding steroid hormone modulators, tamoxifen (TAM and mifepristone (RU486 are widely used in breast cancer therapy and for contraception purposes, respectively. METHODOLOGY/PRINCIPAL FINDINGS: Gene expression profiling of the human endometrial Ishikawa cancer cell line treated with E2 and P4 for 3 h and 12 h, and TAM and RU486 for 12 h, was performed using RNA-sequencing. High levels of mRNA were detected for genes, including PSAP, ATP5G2, ATP5H, and GNB2L1 following E2 or P4 treatment. A total of 82 biomarkers for endometrial biology were identified among E2 induced genes, and 93 among P4 responsive genes. Identified biomarkers included: EZH2, MDK, MUC1, SLIT2, and IL6ST, which are genes previously associated with endometrial receptivity. Moreover, 98.8% and 98.6% of E2 and P4 responsive genes in Ishikawa cells, respectively, were also detected in two human mid-secretory endometrial biopsy samples. TAM treatment exhibited both antagonistic and agonistic effects of E2, and also regulated a subset of genes independently. The cell cycle regulator cyclin D1 (CCND1 showed significant up-regulation following treatment with TAM. RU486 did not appear to act as a pure antagonist of P4 and a functional analysis of RU486 response identified genes related to adhesion and apoptosis, including down-regulated genes associated with cell-cell contacts and adhesion as CTNND1, JUP, CDH2, IQGAP1, and COL2A1. CONCLUSIONS: Significant changes in gene expression by the Ishikawa cell line were detected after treatments with E2, P4, TAM, and RU486. These transcriptome data provide valuable insight into potential biomarkers related to endometrial receptivity, and also facilitate an understanding of the molecular changes that take place in the endometrium in the early stages of breast cancer treatment and contraception usage.

  4. CB1 and CB2 receptors are novel molecular targets for Tamoxifen and 4OH-Tamoxifen

    Energy Technology Data Exchange (ETDEWEB)

    Prather, Paul L. [Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR 72205 (United States); FrancisDevaraj, FeAna; Dates, Centdrika R.; Greer, Aleksandra K.; Bratton, Stacie M. [Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR 72205 (United States); Ford, Benjamin M.; Franks, Lirit N. [Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR 72205 (United States); Radominska-Pandya, Anna, E-mail: RadominskaAnna@uams.edu [Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR 72205 (United States)

    2013-11-15

    Highlights: •Tamoxifen produces cytotoxicity via estrogen-receptor (ER) independent mechanisms. •Tamoxifen binds to CB1 and CB2 cannabinoid receptors and acts as an inverse agonist. •CB1 and CB2 receptors are novel molecular targets for Tamoxifen. •ER-independent effects for Tamoxifen may be mediated via CB1 and/or CB2 receptors. -- Abstract: Tamoxifen (Tam) is classified as a selective estrogen receptor modulator (SERM) and is used for treatment of patients with ER-positive breast cancer. However, it has been shown that Tam and its cytochrome P450-generated metabolite 4-hydroxy-Tam (4OH-Tam) also exhibit cytotoxic effects in ER-negative breast cancer cells. These observations suggest that Tam and 4OH-Tam can produce cytotoxicity via estrogen receptor (ER)-independent mechanism(s) of action. The molecular targets responsible for the ER-independent effects of Tam and its derivatives are poorly understood. Interestingly, similar to Tam and 4OH-Tam, cannabinoids have also been shown to exhibit anti-proliferative and apoptotic effects in ER-negative breast cancer cells, and estrogen can regulate expression levels of cannabinoid receptors (CBRs). Therefore, this study investigated whether CBRs might serve as novel molecular targets for Tam and 4OH-Tam. We report that both compounds bind to CB1 and CB2Rs with moderate affinity (0.9–3 μM). Furthermore, Tam and 4OH-Tam exhibit inverse activity at CB1 and CB2Rs in membrane preparations, reducing basal G-protein activity. Tam and 4OH-Tam also act as CB1/CB2R-inverse agonists to regulate the downstream intracellular effector adenylyl cyclase in intact cells, producing concentration-dependent increases in intracellular cAMP. These results suggest that CBRs are molecular targets for Tam and 4OH-Tam and may contribute to the ER-independent cytotoxic effects reported for these drugs. Importantly, these findings also indicate that Tam and 4OH-Tam might be used as structural scaffolds for development of novel

  5. CB1 and CB2 receptors are novel molecular targets for Tamoxifen and 4OH-Tamoxifen

    International Nuclear Information System (INIS)

    Prather, Paul L.; FrancisDevaraj, FeAna; Dates, Centdrika R.; Greer, Aleksandra K.; Bratton, Stacie M.; Ford, Benjamin M.; Franks, Lirit N.; Radominska-Pandya, Anna

    2013-01-01

    Highlights: •Tamoxifen produces cytotoxicity via estrogen-receptor (ER) independent mechanisms. •Tamoxifen binds to CB1 and CB2 cannabinoid receptors and acts as an inverse agonist. •CB1 and CB2 receptors are novel molecular targets for Tamoxifen. •ER-independent effects for Tamoxifen may be mediated via CB1 and/or CB2 receptors. -- Abstract: Tamoxifen (Tam) is classified as a selective estrogen receptor modulator (SERM) and is used for treatment of patients with ER-positive breast cancer. However, it has been shown that Tam and its cytochrome P450-generated metabolite 4-hydroxy-Tam (4OH-Tam) also exhibit cytotoxic effects in ER-negative breast cancer cells. These observations suggest that Tam and 4OH-Tam can produce cytotoxicity via estrogen receptor (ER)-independent mechanism(s) of action. The molecular targets responsible for the ER-independent effects of Tam and its derivatives are poorly understood. Interestingly, similar to Tam and 4OH-Tam, cannabinoids have also been shown to exhibit anti-proliferative and apoptotic effects in ER-negative breast cancer cells, and estrogen can regulate expression levels of cannabinoid receptors (CBRs). Therefore, this study investigated whether CBRs might serve as novel molecular targets for Tam and 4OH-Tam. We report that both compounds bind to CB1 and CB2Rs with moderate affinity (0.9–3 μM). Furthermore, Tam and 4OH-Tam exhibit inverse activity at CB1 and CB2Rs in membrane preparations, reducing basal G-protein activity. Tam and 4OH-Tam also act as CB1/CB2R-inverse agonists to regulate the downstream intracellular effector adenylyl cyclase in intact cells, producing concentration-dependent increases in intracellular cAMP. These results suggest that CBRs are molecular targets for Tam and 4OH-Tam and may contribute to the ER-independent cytotoxic effects reported for these drugs. Importantly, these findings also indicate that Tam and 4OH-Tam might be used as structural scaffolds for development of novel

  6. Tumorigenic Effects of Tamoxifen on the Female Genital Tract

    Directory of Open Access Journals (Sweden)

    Kaei Nasu M.D., Ph.D.

    2008-01-01

    Full Text Available Tamoxifen is widely used for endocrine treatment and breast cancer prevention. It acts as both an estrogen antagonist in breast tissue and an estrogen agonist in the female lower genital tract. Tamoxifen causes severe gynecologic side effects, such as endometrial cancer. This review focuses on the effects of prolonged tamoxifen treatment on the human female genital tract and considers its tumorigenicity in the gynecologic organs through clinical data analysis. Tamoxifen is associated with an increased incidence of benign endometrial lesions such as polyps and hyperplasia and a two- to four-fold increased risk of endometrial cancer in postmenopausal patients. Moreover, the incidence of functional ovarian cysts is significantly high in premenopausal tamoxifen users. To prevent tamoxifen from having severe side effects in gynecologic organs, frequent gynecological examination should be performed for both premenopausal and postmenopausal patients with breast cancer who are treated with this drug.

  7. Paradoxical action of fulvestrant in estradiol-induced regression of tamoxifen-stimulated breast cancer.

    Science.gov (United States)

    Osipo, Clodia; Gajdos, Csaba; Liu, Hong; Chen, Bin; Jordan, V Craig

    2003-11-05

    Long-term tamoxifen treatment of breast cancer can result in tamoxifen-stimulated breast cancer, in which estrogen inhibits tumor growth after tamoxifen withdrawal. We investigated the molecular mechanism(s) of estradiol-induced tumor regression by using an in vivo model of tamoxifen-stimulated human breast cancer. Growth of parental estradiol-stimulated MCF-7E2 and long-term tamoxifen-stimulated MCF-7TAMLT xenografts in athymic mice was measured during treatment with vehicle, estradiol, estradiol plus tamoxifen, tamoxifen alone, estradiol plus fulvestrant, or fulvestrant alone. Apoptosis was detected by the terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. Protein expression was assessed by western blot analysis. mRNA expression was assessed by real-time reverse transcription-polymerase chain reaction. All statistical tests were two-sided. MCF-7E2 tumor growth was stimulated by estradiol (cross-sectional area at week 13 = 1.06 cm2, 95% confidence interval [CI] = 0.82 to 1.30 cm2; Pestradiol-induced regression to 0.18 cm2 (95% CI = 0.15 to 0.21 cm2; P<.001), and tamoxifen or estradiol plus fulvestrant enhanced tumor growth to 1.00 cm2 (95% CI = 0.88 to 1.22 cm2). Estradiol increased the number of apoptotic cells in tumors by 23% (95% CI = 20% to 26%; P<.001) compared with all other treatments, decreased estrogen receptor alpha(ERalpha) protein expression, increased the expression of Fas mRNA and protein, decreased the expression of HER2/neu mRNA and protein and nuclear factor kappaB (NF-kappaB) protein but did not affect Fas ligand protein expression compared with control. Paradoxically, fulvestrant reversed this effect and stimulated MCF-7TAMLT tumor growth apparently through ERalpha-mediated regulation of Fas, HER2/neu, and NF-kappaB. Physiologic levels of estradiol induced regression of tamoxifen-stimulated breast cancer tumors, apparently by inducing the death receptor Fas and suppressing the antiapoptotic

  8. Estrogen receptor alpha mediates estrogen-inducible abnormalities in the developing penis.

    Science.gov (United States)

    Goyal, H O; Braden, T D; Cooke, P S; Szewczykowski, M A; Williams, C S; Dalvi, P; Williams, J W

    2007-05-01

    Previously, we reported an association between estrogen receptor-alpha (ERalpha) upregulation and detrimental effects of neonatal diethylstilbestrol (DES) exposure in the rat penis. The objective of this study was to employ the ERalpha knockout (ERalphaKO) mouse model to test the hypothesis that ERalpha mediates DES effects in the developing penis. ERalphaKO and wild-type C57BL/6 mice received oil or DES at a dose of 0.2 microg/pup per day (0.1 mg/kg) on alternate days from postnatal days 2 to 12. Fertility was tested at 80-240 days of age and tissues were examined at 96-255 days of age. DES caused malformation of the os penis, significant reductions in penile length, diameter, and weight, accumulation of fat cells in the corpora cavernosa penis, and significant reductions in weight of the bulbospongiosus and levator ani muscles in wild-type mice. Conversely, ERalphaKO mice treated with DES developed none of the above abnormalities. While nine out of ten male mice sired pups in the wild-type/control group, none did in the wild-type/DES group. ERalphaKO mice, despite normal penile development, are inherently infertile. Both plasma and intratesticular testosterone levels were unaltered in the DES-treated wild-type or DES-treated ERalphaKO mice when compared with controls, although testosterone concentration was much higher in the ERalphaKO mice. Hence, the resistance of ERalphaKO mice to developing penile abnormalities provides unequivocal evidence of an obligatory role for ERalpha in mediating the harmful effects of neonatal DES exposure in the developing penis.

  9. Estrogen inhibits glucocorticoid action via protein phosphatase 5 (PP5)-mediated glucocorticoid receptor dephosphorylation.

    Science.gov (United States)

    Zhang, Yong; Leung, Donald Y M; Nordeen, Steven K; Goleva, Elena

    2009-09-04

    Although glucocorticoids suppress proliferation of many cell types and are used in the treatment of certain cancers, trials of glucocorticoid therapy in breast cancer have been a disappointment. Another suggestion that estrogens may affect glucocorticoid action is that the course of some inflammatory diseases tends to be more severe and less responsive to corticosteroid treatment in females. To date, the molecular mechanism of cross-talk between estrogens and glucocorticoids is poorly understood. Here we show that, in both MCF-7 and T47D breast cancer cells, estrogen inhibits glucocorticoid induction of the MKP-1 (mitogen-activated protein kinase phosphatase-1) and serum/glucocorticoid-regulated kinase genes. Estrogen did not affect glucocorticoid-induced glucocorticoid receptor (GR) nuclear translocation but reduced ligand-induced GR phosphorylation at Ser-211, which is associated with the active form of GR. We show that estrogen increases expression of protein phosphatase 5 (PP5), which mediates the dephosphorylation of GR at Ser-211. Gene knockdown of PP5 abolished the estrogen-mediated suppression of GR phosphorylation and induction of MKP-1 and serum/glucocorticoid-regulated kinase. More importantly, after PP5 knockdown estrogen-promoted cell proliferation was significantly suppressed by glucocorticoids. This study demonstrates cross-talk between estrogen-induced PP5 and GR action. It also reveals that PP5 inhibition may antagonize estrogen-promoted events in response to corticosteroid therapy.

  10. Effects of gamma irradiation on the DNA-protein complex between the estrogen response element and the estrogen receptor

    Energy Technology Data Exchange (ETDEWEB)

    Stisova, Viktorie [Department of Radiation Dosimetry, Nuclear Physics Institute AS CR, Na Truhlarce 39/64, 18086 Praha 8 (Czech Republic); Goffinont, Stephane; Spotheim-Maurizot, Melanie [Centre de Biophysique Moleculaire CNRS, rue Charles Sadron, 45071 Orleans Cedex 2 (France); Davidkova, Marie, E-mail: davidkova@ujf.cas.c [Department of Radiation Dosimetry, Nuclear Physics Institute AS CR, Na Truhlarce 39/64, 18086 Praha 8 (Czech Republic)

    2010-08-15

    Signaling by estrogens, risk factors in breast cancer, is mediated through their binding to the estrogen receptor protein (ER), followed by the formation of a complex between ER and a DNA sequence, called estrogen response element (ERE). Anti-estrogens act as competitive inhibitors by blocking the signal transduction. We have studied in vitro the radiosensitivity of the complex between ERalpha, a subtype of this receptor, and a DNA fragment bearing ERE, as well as the influence of an estrogen (estradiol) or an anti-estrogen (tamoxifen) on this radiosensitivity. We observe that the complex is destabilized upon irradiation with gamma rays in aerated aqueous solution. The analysis of the decrease of binding abilities of the two partners shows that destabilization is mainly due to the damage to the protein. The destabilization is reduced when irradiating in presence of tamoxifen and is increased in presence of estradiol. These effects are due to opposite influences of the ligands on the loss of binding ability of ER. The mechanism that can account for our results is: binding of estradiol or tamoxifen induces distinct structural changes of the ER ligand-binding domain that can trigger (by allostery) distinct structural changes of the ER DNA-binding domains and thus, can differently affect ER-ERE interaction.

  11. Tamoxifen induces a pluripotency signature in breast cancer cells and human tumors.

    Science.gov (United States)

    Notas, George; Pelekanou, Vassiliki; Kampa, Marilena; Alexakis, Konstantinos; Sfakianakis, Stelios; Laliotis, Aggelos; Askoxilakis, John; Tsentelierou, Eleftheria; Tzardi, Maria; Tsapis, Andreas; Castanas, Elias

    2015-11-01

    Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients that are eligible for adjuvant endocrine therapy. However, ∼50% of ERα-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment. Unfortunately, prediction of de novo resistance to endocrine therapy and/or assessment of relapse likelihood remain difficult. While several mechanisms regulating the acquisition and the maintenance of endocrine resistance have been reported, there are several aspects of this phenomenon that need to be further elucidated. Altered metabolic fate of tamoxifen within patients and emergence of tamoxifen-resistant clones, driven by evolution of the disease phenotype during treatment, appear as the most compelling hypotheses so far. In addition, tamoxifen was reported to induce pluripotency in breast cancer cell lines, in vitro. In this context, we have performed a whole transcriptome analysis of an ERα-positive (T47D) and a triple-negative breast cancer cell line (MDA-MB-231), exposed to tamoxifen for a short time frame (hours), in order to identify how early pluripotency-related effects of tamoxifen may occur. Our ultimate goal was to identify whether the transcriptional actions of tamoxifen related to induction of pluripotency are mediated through specific ER-dependent or independent mechanisms. We report that even as early as 3 hours after the exposure of breast cancer cells to tamoxifen, a subset of ERα-dependent genes associated with developmental processes and pluripotency are induced and this is accompanied by specific phenotypic changes (expression of pluripotency-related proteins). Furthermore we report an association between the increased expression of pluripotency-related genes in ERα-positive breast cancer tissues samples and disease relapse after tamoxifen therapy. Finally we describe that in a small group of ERα-positive breast cancer patients, with disease relapse after surgery and tamoxifen treatment, ALDH

  12. ERBB2 influences the subcellular localization of the estrogen receptor in tamoxifen-resistant MCF-7 cells leading to the activation of AKT and RPS6KA2.

    Science.gov (United States)

    Pancholi, Sunil; Lykkesfeldt, Anne E; Hilmi, Caroline; Banerjee, Susana; Leary, Alexandra; Drury, Suzanne; Johnston, Stephen; Dowsett, Mitch; Martin, Lesley-Ann

    2008-12-01

    Acquired resistance to endocrine therapies remains a major clinical obstacle in hormone-sensitive breast tumors. We used an MCF-7 breast tumor cell line (Tam(R)-1) resistant to tamoxifen to investigate this mechanism. We demonstrate that Tam(R)-1 express elevated levels of phosphorylated AKT and MAPK3/1-activated RPS6KA2 compared with the parental MCF-7 cell line (MCF-7). There was no change in the level of total ESR between the two cell lines; however, the Tam(R)-1 cells had increased phosphorylation of ESR1 ser(167). SiRNA blockade of AKT or MAPK3/1 had little effect on ESR1 ser(167) phosphorylation, but a combination of the two siRNAs abrogated this. Co-localization studies revealed an association between ERBB2 and ESR1 in the Tam(R)-1 but not MCF-7 cells. ESR1 was redistributed to extranuclear sites in Tam(R)-1 and was less transcriptionally competent compared with MCF-7 suggesting that nuclear ESR1 activity was suppressed in Tam(R)-1. Tamoxifen resistance in the Tam(R)-1 cells could be partially overcome by the ERBB2 inhibitor AG825 in combination with tamoxifen, and this was associated with re-localization of ESR1 to the nucleus. These data demonstrate that tamoxifen-resistant cells have the ability to switch between ERBB2 or ESR1 pathways promoting cell growth and that pharmacological inhibition of ERBB2 may be a therapeutic strategy for overcoming tamoxifen resistance.

  13. Estrogen-Mediated Breast Carcinogenesis: The Role of Sulfation Pharmacogenetics

    Science.gov (United States)

    2002-05-01

    WHAT? Sulfate -conjugation catalyzed by SULTs is one of the major important pathways in the biotransformation of drugs, xenobiotics , neurotransmitters...requests should be ad- estrogens-as well as neurotransmitters, xenobiotics and dressed. Fax: (507) 284-9111. E-mail: weinshilboum.richard@ many drugs...45. Klauber, N., Parangi, S., Flynn, E., Hamel, E., and D’Amato, dogenous estrogen exposure, well-done meat intake, and R. J. (1997) Inhibition of

  14. Oxidative stress contributes to the tamoxifen-induced killing of breast cancer cells: implications for tamoxifen therapy and resistance.

    Science.gov (United States)

    Bekele, Raie T; Venkatraman, Ganesh; Liu, Rong-Zong; Tang, Xiaoyun; Mi, Si; Benesch, Matthew G K; Mackey, John R; Godbout, Roseline; Curtis, Jonathan M; McMullen, Todd P W; Brindley, David N

    2016-02-17

    Tamoxifen is the accepted therapy for patients with estrogen receptor-α (ERα)-positive breast cancer. However, clinical resistance to tamoxifen, as demonstrated by recurrence or progression on therapy, is frequent and precedes death from metastases. To improve breast cancer treatment it is vital to understand the mechanisms that result in tamoxifen resistance. This study shows that concentrations of tamoxifen and its metabolites, which accumulate in tumors of patients, killed both ERα-positive and ERα-negative breast cancer cells. This depended on oxidative damage and anti-oxidants rescued the cancer cells from tamoxifen-induced apoptosis. Breast cancer cells responded to tamoxifen-induced oxidation by increasing Nrf2 expression and subsequent activation of the anti-oxidant response element (ARE). This increased the transcription of anti-oxidant genes and multidrug resistance transporters. As a result, breast cancer cells are able to destroy or export toxic oxidation products leading to increased survival from tamoxifen-induced oxidative damage. These responses in cancer cells also occur in breast tumors of tamoxifen-treated mice. Additionally, high levels of expression of Nrf2, ABCC1, ABCC3 plus NAD(P)H dehydrogenase quinone-1 in breast tumors of patients at the time of diagnosis were prognostic of poor survival after tamoxifen therapy. Therefore, overcoming tamoxifen-induced activation of the ARE could increase the efficacy of tamoxifen in treating breast cancer.

  15. An overlooked connection: serotonergic mediation of estrogen-related physiology and pathology

    Directory of Open Access Journals (Sweden)

    Gilders Roger M

    2005-12-01

    Full Text Available Abstract Background In humans, serotonin has typically been investigated as a neurotransmitter. However, serotonin also functions as a hormone across animal phyla, including those lacking an organized central nervous system. This hormonal action allows serotonin to have physiological consequences in systems outside the central nervous system. Fluctuations in estrogen levels over the lifespan and during ovarian cycles cause predictable changes in serotonin systems in female mammals. Discussion We hypothesize that some of the physiological effects attributed to estrogen may be a consequence of estrogen-related changes in serotonin efficacy and receptor distribution. Here, we integrate data from endocrinology, molecular biology, neuroscience, and epidemiology to propose that serotonin may mediate the effects of estrogen. In the central nervous system, estrogen influences pain transmission, headache, dizziness, nausea, and depression, all of which are known to be a consequence of serotonergic signaling. Outside of the central nervous system, estrogen produces changes in bone density, vascular function, and immune cell self-recognition and activation that are consistent with serotonin's effects. For breast cancer risk, our hypothesis predicts heretofore unexplained observations of the opposing effects of obesity pre- and post-menopause and the increase following treatment with hormone replacement therapy using medroxyprogesterone. Summary Serotonergic mediation of estrogen has important clinical implications and warrants further evaluation.

  16. Distinct Hypothalamic Neurons Mediate Estrogenic Effects on Energy Homeostasis and Reproduction

    OpenAIRE

    Xu, Yong; Nedungadi, Thekkethil P.; Zhu, Liangru; Sobhani, Nasim; Irani, Boman G.; Davis, Kathryn E.; Zhang, Xiaorui; Zou, Fang; Gent, Lana M.; Hahner, Lisa D.; Khan, Sohaib A.; Elias, Carol F.; Elmquist, Joel K.; Clegg, Deborah J.

    2011-01-01

    Estrogens regulate body weight and reproduction primarily through actions on estrogen receptor-α (ERα). However, ERα-expressing cells mediating these effects are not identified. We demonstrate that brain-specific deletion of ERα in female mice causes abdominal obesity stemming from both hyperphagia and hypometabolism. Hypometabolism and abdominal obesity, but not hyperphagia, are recapitulated in female mice lacking ERα in hypothalamic steroidogenic factor-1 (SF1) neurons. In contrast, deleti...

  17. Effects of tamoxifen on vaginal blood flow and epithelial morphology in the rat

    Directory of Open Access Journals (Sweden)

    Goldstein Irwin

    2006-09-01

    Full Text Available Abstract Background Tamoxifen, a selective estrogen receptor modulator with both estrogenic and anti-estrogenic activity, is widely used as adjuvant therapy in breast cancer patients. Treatment with tamoxifen is associated with sexual side effects, such as increased vaginal dryness and pain/discomfort during sexual activity. There have been limited investigations of the effect of tamoxifen on estrogen-dependent peripheral genital arousal responses. The objective of this study was to investigate the effects of tamoxifen on vaginal physiology in the rat. Methods Female Sprague-Dawley rats were subjected to sham surgery or bilateral ovariectomy. After 2 weeks, sham-operated rats were implanted with subcutaneous osmotic infusion pumps containing vehicle (control or tamoxifen (150 μg/day. Ovariectomized rats were similarly infused with vehicle. After an additional 2 weeks, vaginal blood flow responses to pelvic nerve stimulation were measured by laser Doppler flowmetry and vaginal tissue was collected for histological and biochemical assay. Results Tamoxifen treatment did not change plasma estradiol concentrations relative to control animals, while ovariectomized rats exhibited a 60% decrease in plasma estradiol. Tamoxifen treatment caused a significant decrease in mean uterine weight, but did not alter mean vaginal weight. Vaginal blood flow was significantly decreased in tamoxifen-infused rats compared to controls. Similar to ovariectomized animals, estrogen receptor binding was increased and arginase enzyme activity was decreased in tamoxifen-infused rats. However, different from control and ovariectomized animals, the vaginal epithelium in tamoxifen-infused rats appeared highly mucified. Periodic acid-Schiff staining confirmed a greater production of carbohydrate-rich compounds (e.g. mucin, glycogen by the vaginal epithelium of tamoxifen-infused rats. Conclusion The observations suggest that tamoxifen exerts both anti-estrogenic and pro-estrogenic

  18. Combination treatment of tamoxifen with risperidone in breast cancer.

    Directory of Open Access Journals (Sweden)

    Wei-Lan Yeh

    Full Text Available Tamoxifen has long been used and still is the most commonly used endocrine therapy for treatment of both early and advanced estrogen receptor-positive breast cancer in pre- and post-menopause women. Tamoxifen exerts its cytotoxic effect primarily through cytostasis which is associated with the accumulation of cells in the G0/G1 phase of the cell cycle. Apoptotic activity can also be exerted by tamoxifen which involves cleavage of caspase 9, caspase 7, caspase 3, and poly-ADP-ribose polymerase (PARP. Down-regulation of anti-apoptotic proteins Bcl-2 and Bcl-xL and up-regulation of pro-apoptotic proteins Bax and Bak have also been observed. In addition, stress response protein of GRP 94 and GRP 78 have also been induced by tamoxifen in our study. However, side effects occur during tamoxifen treatment in breast cancer patients. Researching into combination regimen of tamoxifen and drug(s that relieves tamoxifen-induced hot flushes is important, because drug interactions may decrease tamoxifen efficacy. Risperidone has been shown to be effective in reducing or eliminating hot flushes on women with hormonal variations. In this present study, we demonstrated that combination of tamoxifen with risperidone did not interfered tamoxifen-induced cytotoxic effects in both in vitro and in vivo models, while fluoxetine abrogated the effects of tamoxifen. This is the first paper suggesting the possibility of combination treatment of tamoxifen with risperidone in breast cancer patients, providing a conceivable resolution of tamoxifen-induced side effects without interfering the efficacy of tamoxifen against breast cancer.

  19. Combination Treatment of Tamoxifen with Risperidone in Breast Cancer

    Science.gov (United States)

    Yeh, Wei-Lan; Lin, Hui-Yi; Wu, Hung-Ming; Chen, Dar-Ren

    2014-01-01

    Tamoxifen has long been used and still is the most commonly used endocrine therapy for treatment of both early and advanced estrogen receptor-positive breast cancer in pre- and post-menopause women. Tamoxifen exerts its cytotoxic effect primarily through cytostasis which is associated with the accumulation of cells in the G0/G1 phase of the cell cycle. Apoptotic activity can also be exerted by tamoxifen which involves cleavage of caspase 9, caspase 7, caspase 3, and poly-ADP-ribose polymerase (PARP). Down-regulation of anti-apoptotic proteins Bcl-2 and Bcl-xL and up-regulation of pro-apoptotic proteins Bax and Bak have also been observed. In addition, stress response protein of GRP 94 and GRP 78 have also been induced by tamoxifen in our study. However, side effects occur during tamoxifen treatment in breast cancer patients. Researching into combination regimen of tamoxifen and drug(s) that relieves tamoxifen-induced hot flushes is important, because drug interactions may decrease tamoxifen efficacy. Risperidone has been shown to be effective in reducing or eliminating hot flushes on women with hormonal variations. In this present study, we demonstrated that combination of tamoxifen with risperidone did not interfered tamoxifen-induced cytotoxic effects in both in vitro and in vivo models, while fluoxetine abrogated the effects of tamoxifen. This is the first paper suggesting the possibility of combination treatment of tamoxifen with risperidone in breast cancer patients, providing a conceivable resolution of tamoxifen-induced side effects without interfering the efficacy of tamoxifen against breast cancer. PMID:24886861

  20. Food-associated estrogenic compounds induce estrogen receptor-mediated luciferase gene expression in transgenic male mice.

    Science.gov (United States)

    Ter Veld, Marcel G R; Zawadzka, E; van den Berg, J H J; van der Saag, Paul T; Rietjens, Ivonne M C M; Murk, Albertinka J

    2008-07-30

    The present paper aims at clarifying to what extent seven food-associated compounds, shown before to be estrogenic in vitro, can induce estrogenic effects in male mice with an estrogen receptor (ER)-mediated luciferase (luc) reporter gene system. The luc induction was determined in different tissues 8h after dosing the ER-luc male mice intraperitoneally (IP) or 14h after oral dosing. Estradiol-propionate (EP) was used as a positive control at 0.3 and 1mg/kg bodyweight (bw), DMSO as solvent control. The food-associated estrogenic compounds tested at non-toxic doses were bisphenol A (BPA) and nonylphenol (NP) (both at 10 and 50mg/kgbw), dichlorodiphenyldichloroethylene (p,p'-DDE; at 5 and 25mg/kgbw), quercetin (at 1.66 and 16.6mg/kgbw), di-isoheptyl phthalate (DIHP), di-(2-ethylhexyl) phthalate (DEHP) and di-(2-ethylhexyl) adipate (DEHA) all at 30 and 100mg/kgbw. In general IP dosing resulted in higher luc inductions than oral dosing. EP induced luc activity in the liver in a statistically significant dose-related way with the highest induction of all compounds tested which was 20,000 times higher than the induction by the DMSO-control. NP, DDE, DEHA and DIHP did not induce luc activity in any of the tissues tested. BPA induced luc in the liver up to 420 times via both exposure routes. BPA, DEHP and quercetin induced luc activity in the liver after oral exposure. BPA (50mg/kgbw IP) also induced luc activity in the testis, kidneys and tibia. The current study reveals that biomarker-responses in ER-luc male mice occur after a single oral exposure to food-associated estrogenic model compounds at exposure levels 10 to 10(4) times higher than the established TDI's for some of these compounds. Given the facts that (i) the present study did not include chronic exposure and that (ii) simultaneous exposure to multiple estrogenic compounds may be a realistic exposure scenario, it remains to be seen whether this margin is sufficiently high.

  1. GPR30 mediates anorectic estrogen-induced STAT3 signaling in the hypothalamus.

    Science.gov (United States)

    Kwon, Obin; Kang, Eun Seok; Kim, Insook; Shin, Sora; Kim, Mijung; Kwon, Somin; Oh, So Ra; Ahn, Young Soo; Kim, Chul Hoon

    2014-11-01

    Estrogen plays an important role in the control of energy balance in the hypothalamus. Leptin-independent STAT3 activation (i.e., tyrosine(705)-phosphorylation of STAT3, pSTAT3) in the hypothalamus is hypothesized as the primary mechanism of the estrogen-induced anorexic response. However, the type of estrogen receptor that mediates this regulation is unknown. We investigated the role of the G protein-coupled receptor 30 (GPR30) in estradiol (E2)-induced STAT3 activation in the hypothalamus. Regulation of STAT3 activation by E2, G-1, a specific agonist of GPR30 and G-15, a specific antagonist of GPR30 was analyzed in vitro and in vivo. Effect of GPR30 activation on eating behavior was analyzed in vivo. E2 stimulated pSTAT3 in cells expressing GPR30, but not expressing estrogen receptor ERα and ERβ. G-1 induced pSTAT3, and G-15 inhibited E2-induced pSTAT3 in primary cultures of hypothalamic neurons. A cerebroventricular injection of G-1 increased pSTAT3 in the arcuate nucleus of mice, which was associated with a decrease in food intake and body weight gain. These results suggest that GPR30 is the estrogen receptor that mediates the anorectic effect of estrogen through the STAT3 pathway in the hypothalamus. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Tamoxifen or letrozole versus standard methods for women with estrogen-receptor positive breast cancer undergoing oocyte or embryo cryopreservation in assisted reproduction

    NARCIS (Netherlands)

    Dahhan, Taghride; Balkenende, Eva; van Wely, Madelon; Linn, Sabine; Goddijn, Mariette

    2013-01-01

    Cryopreservation of oocytes or embryos preceded by controlled ovarian stimulation (COS) can increase the chance of future pregnancy in women with breast cancer who risk therapy-induced ovarian failure. In women with estrogen-receptor (ER) positive breast cancer, alternative COS protocols with

  3. Genomics of signaling crosstalk of estrogen receptor alpha in breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Peter Dudek

    Full Text Available BACKGROUND: The estrogen receptor alpha (ERalpha is a ligand-regulated transcription factor. However, a wide variety of other extracellular signals can activate ERalpha in the absence of estrogen. The impact of these alternate modes of activation on gene expression profiles has not been characterized. METHODOLOGY/PRINCIPAL FINDINGS: We show that estrogen, growth factors and cAMP elicit surprisingly distinct ERalpha-dependent transcriptional responses in human MCF7 breast cancer cells. In response to growth factors and cAMP, ERalpha primarily activates and represses genes, respectively. The combined treatments with the anti-estrogen tamoxifen and cAMP or growth factors regulate yet other sets of genes. In many cases, tamoxifen is perverted to an agonist, potentially mimicking what is happening in certain tamoxifen-resistant breast tumors and emphasizing the importance of the cellular signaling environment. Using a computational analysis, we predicted that a Hox protein might be involved in mediating such combinatorial effects, and then confirmed it experimentally. Although both tamoxifen and cAMP block the proliferation of MCF7 cells, their combined application stimulates it, and this can be blocked with a dominant-negative Hox mutant. CONCLUSIONS/SIGNIFICANCE: The activating signal dictates both target gene selection and regulation by ERalpha, and this has consequences on global gene expression patterns that may be relevant to understanding the progression of ERalpha-dependent carcinomas.

  4. Effect of conjugated equine estrogens and tamoxifen administration on thyroid gland histomorphology of the rat Os efeitos dos estrogênios conjugados equinos e do tamoxifeno na histomorfologia da glândula tireóide de ratas

    Directory of Open Access Journals (Sweden)

    Luiz Felipe Bittencourt de Araujo

    2006-08-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the action of the conjugated equine estrogens and tamoxifen on the morphology of thyroid gland in ovariectomized (OVx rats. METHODS: Conjugated equine estrogens (CEE, clinically used as estrogen therapy, is a complex formulation containing multiple estrogens that decrease menopausal symptoms. Thirty ovariectomized rats were randomly divided into 3 treatment groups: GI, vehicle (propylene glycol; GII, CEE 200 µg/kg per day; and GIII, tamoxifen 1 mg/kg per day. Another group of 10 rats with intact ovaries (GIV was included, treated with the vehicle, and sacrificed during estrous. All animals were treated by gavage for 50 days, after which they were sacrificed. Blood samples were collected, and the thyroid was removed for morphological analysis and PCNA evaluation through immunohistochemical study. RESULTS: The thyroid follicular cell height was increased in animals treated with CEE (14.90 ± 0.20 µm, with TAM (14.90 ± 0.10 µm, and in rats with intact ovaries (15.10 ± 0.50 µm in comparison to that of the vehicle group (9.90 ± 0.20 µm (P OBJETIVO: Avaliar a ação dos estrogênios conjugados eqüinos e do tamoxifeno na histomorfologia da tireóide de ratas. MÉTODO: Estrogênios conjugados eqüinos são ministrados clinicamente como terapia estrogênica e contêm formulação complexa com muitos tipos de estrogênios que diminuem os sintomas da pós-menopausa. Trinta ratas adultas ooforectomizadas foram divididas aleatoriamente em três grupos: GI - veículo (propilenoglicol; GII - ECE 200 µg/Kg por dia; e GIII - TAM 1 mg/Kg por dia. Acrescentou-se ainda um grupo de 10 animais com os ovários intactos e tratados com veículo (GIV. Todos os animais foram tratados por gavagem durante 50 dias consecutivos, ao final foram coletadas amostras do sangue e a tireóide removida e processada para análise morfológica e imunohistoquímico para avaliar o PCNA. RESULTADOS: A maior altura das c

  5. Endogenous Estrogen-Mediated Heme Oxygenase Regulation in Experimental Menopause

    Directory of Open Access Journals (Sweden)

    Anikó Pósa

    2015-01-01

    Full Text Available Estrogen deficiency is one of the main causes of age-associated diseases in the cardiovascular system. Female Wistar rats were divided into four experimental groups: pharmacologically ovariectomized, surgically ovariectomized, and 24-month-old intact aging animals were compared with a control group. The activity and expression of heme oxygenases (HO in the cardiac left ventricle, the concentrations of cardiac interleukin-6 (IL-6 and tumor necrosis factor-α (TNF-α, the myeloperoxidase (MPO activity in the cardiac left ventricle, and the effects of heme oxygenase blockade (by 24-hour and 1-hour pretreatment with tin-protoporphyrin IX, SnPP on the epinephrine and phentolamine-induced electrocardiogram ST segment changes in vivo were investigated. The cardiac HO activity and the expression of HO-1 and HO-2 were significantly decreased in the aged rats and after ovariectomy. Estrogen depletion was accompanied by significant increases in the expression of IL-6 and TNF-α. The aged and ovariectomized animals exhibited a significantly elevated MPO activity and a significant ST segment depression. After pretreatment with SnPP augmented ST segment changes were determined. These findings demonstrate that the sensitivity to cardiac ischemia in estrogen depletion models is associated with suppression of the activity and expression of the HO system and increases in the secretion of proinflammatory cytokines and biomarkers.

  6. Induction of aryl hydrocarbon receptor-mediated and estrogen receptor-mediated activities, and modulation of cell proliferation by dinaphthofurans

    Czech Academy of Sciences Publication Activity Database

    Vondráček, Jan; Chramostová, Kateřina; Plíšková, M.; Bláha, L.; Brack, W.; Kozubík, Alois; Machala, M.

    2004-01-01

    Roč. 23, č. 9 (2004), s. 2214-2220 ISSN 0730-7268 R&D Projects: GA ČR GA525/03/1527 Institutional research plan: CEZ:AV0Z5004920 Keywords : aryl hydrocarbon receptor-mediated activity * estrogenicity * intercellular communication inhibition Subject RIV: BO - Biophysics Impact factor: 2.121, year: 2004

  7. Androgen and estrogen receptor mediated mechanisms of testosterone action in male rat pelvic autonomic ganglia

    Science.gov (United States)

    Purves-Tyson, T.D.; Arshi, M.S.; Handelsman, D. J.; Cheng, Y.; Keast, J. R.

    2007-01-01

    Although male reproductive function is primarily androgen dependent, many studies suggest that estrogens have direct actions on the male reproductive organs. Pelvic autonomic neurons provide the motor control of the internal reproductive organs and the penis and various properties of these neurons are affected by endogenous androgens. However, the possible role of estrogens at this site has not been examined. Here we have investigated the significance of estrogens produced by aromatisation of testosterone in the physiological actions of androgens on adult male rat pelvic ganglion neurons. RT-PCR studies showed that aromatase and both estrogen receptors (ERα and ERβ) are expressed in these ganglia. Western blotting also showed that aromatase is expressed in male pelvic ganglia. Using immunohistochemical visualisation, ERα was predominantly expressed by nitric oxide synthase (NOS)-positive parasympathetic pelvic ganglion neurons. In vivo studies showed that the decrease in pelvic ganglion soma size caused by gonadectomy could be prevented by administration of testosterone (T) or dihydrotestosterone (DHT), but not 17β-estradiol (E2), showing that this maintenance action of testosterone is mediated entirely by androgenic mechanisms. However, in vitro studies of cultured pelvic ganglion neurons revealed that T, DHT and E each stimulated the growth of longer and more complex neurites in both noradrenergic and cholinergic NOS-expressing neurons. The effects of T were attenuated by either androgen or estrogen receptor antagonists, or by inhibition of aromatase. Together these studies demonstrate that estrogens are likely to be synthesised in the male pelvic ganglia, produced from testosterone by local aromatase. The effects of androgens on axonal growth are likely to be at least partly mediated by estrogenic mechanisms, which may be important for understanding disease-, aging- and injury-induced plasticity in this part of the nervous system. PMID:17629410

  8. Androgen and estrogen receptor-mediated mechanisms of testosterone action in male rat pelvic autonomic ganglia.

    Science.gov (United States)

    Purves-Tyson, T D; Arshi, M S; Handelsman, D J; Cheng, Y; Keast, J R

    2007-08-10

    Although male reproductive function is primarily androgen dependent, many studies suggest that estrogens have direct actions on the male reproductive organs. Pelvic autonomic neurons provide the motor control of the internal reproductive organs and the penis and various properties of these neurons are affected by endogenous androgens. However, the possible role of estrogens at this site has not been examined. Here we have investigated the significance of estrogens produced by aromatization of testosterone (T) in the physiological actions of androgens on adult male rat pelvic ganglion neurons. Reverse transcriptase polymerase chain reaction (RT-PCR) studies showed that aromatase and both estrogen receptors (ERalpha and ERbeta) are expressed in these ganglia. Western blotting also showed that aromatase is expressed in male pelvic ganglia. Using immunohistochemical visualization, ERalpha was predominantly expressed by nitric oxide synthase (NOS)-positive parasympathetic pelvic ganglion neurons. In vivo studies showed that the decrease in pelvic ganglion soma size caused by gonadectomy could be prevented by administration of T or dihydrotestosterone (DHT), but not 17beta-estradiol (E2), showing that this maintenance action of testosterone is mediated entirely by androgenic mechanisms. However, in vitro studies of cultured pelvic ganglion neurons revealed that T, DHT and E each stimulated the growth of longer and more complex neurites in both noradrenergic and cholinergic NOS-expressing neurons. The effects of T were attenuated by either androgen or estrogen receptor antagonists, or by inhibition of aromatase. Together these studies demonstrate that estrogens are likely to be synthesized in the male pelvic ganglia, produced from T by local aromatase. The effects of androgens on axonal growth are likely to be at least partly mediated by estrogenic mechanisms, which may be important for understanding disease-, aging- and injury-induced plasticity in this part of the

  9. A SNP in steroid receptor coactivator-1 disrupts a GSK3β phosphorylation site and is associated with altered tamoxifen response in bone.

    Science.gov (United States)

    Hartmaier, R J; Richter, A S; Gillihan, R M; Sallit, J Z; McGuire, S E; Wang, J; Lee, A V; Osborne, C K; O'Malley, B W; Brown, P H; Xu, J; Skaar, T C; Philips, S; Rae, J M; Azzouz, F; Li, L; Hayden, J; Henry, N L; Nguyen, A T; Stearns, V; Hayes, D F; Flockhart, D A; Oesterreich, S

    2012-02-01

    The coregulator steroid receptor coactivator (SRC)-1 increases transcriptional activity of the estrogen receptor (ER) in a number of tissues including bone. Mice deficient in SRC-1 are osteopenic and display skeletal resistance to estrogen treatment. SRC-1 is also known to modulate effects of selective ER modulators like tamoxifen. We hypothesized that single nucleotide polymorphisms (SNP) in SRC-1 may impact estrogen and/or tamoxifen action. Because the only nonsynonymous SNP in SRC-1 (rs1804645; P1272S) is located in an activation domain, it was examined for effects on estrogen and tamoxifen action. SRC-1 P1272S showed a decreased ability to coactivate ER compared with wild-type SRC-1 in multiple cell lines. Paradoxically, SRC-1 P1272S had an increased protein half-life. The Pro to Ser change disrupts a putative glycogen synthase 3 (GSK3)β phosphorylation site that was confirmed by in vitro kinase assays. Finally, knockdown of GSK3β increased SRC-1 protein levels, mimicking the loss of phosphorylation at P1272S. These findings are similar to the GSK3β-mediated phospho-ubiquitin clock previously described for the related coregulator SRC-3. To assess the potential clinical significance of this SNP, we examined whether there was an association between SRC-1 P1272S and selective ER modulators response in bone. SRC-1 P1272S was associated with a decrease in hip and lumbar bone mineral density in women receiving tamoxifen treatment, supporting our in vitro findings for decreased ER coactivation. In summary, we have identified a functional genetic variant of SRC-1 with decreased activity, resulting, at least in part, from the loss of a GSK3β phosphorylation site, which was also associated with decreased bone mineral density in tamoxifen-treated women.

  10. Estrogen-mediated Height Control in Girls with Marfan Syndrome.

    Science.gov (United States)

    Lee, Dong-Yun; Hyun, Hye Sun; Huh, Rimm; Jin, Dong-Kyu; Kim, Duk-Kyung; Yoon, Byung-Koo; Choi, DooSeok

    2016-02-01

    This study evaluated the efficacy of a stepwise regimen of estradiol valerate for height control in girls with Marfan syndrome. Eight girls with Marfan syndrome who had completed estrogen treatment for height control were included. Estradiol valerate was started at a dose of 2 mg/day, and then was increased. The projected final height was estimated using the initial height percentile (on a disease-specific growth curve for Korean Marfan syndrome [gcPFHt]), and the initial bone age (baPFHt). After the estrogen treatment, the projected final height was compared to the actual final height (FHt). The median baseline chronological and bone age were 10.0 and 10.5 years, respectively. After a median of 36.5 months of treatment, the median FHt (172.6 cm) was shorter than the median gcPFHt (181.0 cm) and baPFHt (175.9 cm). In the six patients who started treatment before the age of 11 years, the median FHt (171.8 cm) was shorter than the median gcPFHt (181.5 cm) and baPFHt (177.4 cm) after treatment. The median differences between the FHt and gcPFHt and baPFHt were 9.2 and 8.3 cm, respectively. In two patients started treatment after the age of 11, the differences between FHt and gcPFHt, and baPFHt after treatment were -4 and 1.4 cm, and -1.2 and 0 cm for each case, respectively. A stepwise increasing regimen of estradiol valerate may be an effective treatment for height control in girls with Marfan syndrome, especially when started under 11 years old.

  11. Quantifying mediating effects of endogenous estrogen and insulin in the relation between obesity, alcohol consumption, and breast cancer

    DEFF Research Database (Denmark)

    Hvidtfeldt, Ulla A; Gunter, Marc J; Lange, Theis

    2012-01-01

    Increased exposure to endogenous estrogen and/or insulin may partly explain the relationship of obesity, physical inactivity, and alcohol consumption and postmenopausal breast cancer. However, these potential mediating effects have not been formally quantified in a survival analysis setting....

  12. Biopolymer mediated nanoparticles synthesized from Adenia hondala for enhanced tamoxifen drug delivery in breast cancer cell line

    Science.gov (United States)

    Varadharajaperumal, Pradeepa; Subramanian, Balakumar; Santhanam, Amutha

    2017-09-01

    Silver nanoparticles (AgNPs) are an important class of nanomaterials, which have used as antimicrobial and disinfectant agents due to their detrimental effect on target cells. In the present study it was explored to deliver a novel tamoxifen drug system that can be used in breast cancer treatment, based on chitosan coated silver nanoparticles on MCF-7 human breast cancer cells. AgNPs synthesized from Adenia hondala tuber extract were used to make the chitosan coated AgNPs (Ch-AgNPs), in which the drug tamoxifen was loaded on chitosan coated silver nanoparticles (Tam-Ch-AgNPs) to construct drug loaded nanoparticles as drug delivery system. The morphology and characteristics of the Ch-AgNPs were investigated by UV, FTIR, zeta potential and FESEM. Furthermore, the toxicity of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs was evaluated through cell viability, lactate dehydrogenase leakage, reactive oxygen species generation, caspase-3, DNA laddering, and TUNEL assay in human breast cancer cells (MCF-7) and HBL-100 continuous cell line as a control. Treatment of cancer cells with various concentrations of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs for 24 h revealed that Tam-Ch-AgNPs could inhibit cell viability and induce significant membrane leakage in a dose-dependent manner. Cells exposed to Tam-Ch-AgNPs showed increased reactive oxygen species and hydroxyl radical production when compared to AgNPs, Ch-AgNPs. Furthermore, the apoptotic effects of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs were confirmed by activation of caspase-3 and DNA nuclear fragmentation. The present findings suggest that Tam-Ch-AgNPs could contribute to the development of a suitable anticancer drug delivery.

  13. Approaches for predicting effects of unintended environmental exposure to an endocrine active pharmaceutical, tamoxifen

    Science.gov (United States)

    Tamoxifen is an endocrine-active pharmaceutical (EAP) that is used world-wide. Because tamoxifen is a ubiquitous pharmaceutical and interacts with estrogen receptors, a case study was conducted with this compound to (1) determine effects on reproductive endpoints in a nontarget s...

  14. Tamoxifen for Breast Cancer

    Directory of Open Access Journals (Sweden)

    A Karn

    2010-03-01

    Full Text Available Breast cancer is one of the common cancers. Hormonal therapy along with surgery, chemotherapy, radiotherapy and targeted therapy are vital modalities for the management of breast cancer. Tamoxifen has been the most widely used hormonal therapy for more than two decades. In this article we review the benefits, dose, duration and timing of Tamoxifen therapy in patients with breast cancer. Keywords: breast cancer, hormonal therapy, tamoxifen.

  15. Mixed lineage leukemia histone methylases play critical roles in estrogen-mediated regulation of HOXC13.

    Science.gov (United States)

    Ansari, Khairul I; Kasiri, Sahba; Hussain, Imran; Mandal, Subhrangsu S

    2009-12-01

    HOXC13, a homeobox-containing gene, is involved in hair development and human leukemia. The regulatory mechanism that drives HOXC13 expression is mostly unknown. Our studies have demonstrated that HOXC13 is transcriptionally activated by the steroid hormone estrogen (17beta-estradiol; E2). The HOXC13 promoter contains several estrogen-response elements (EREs), including ERE1 and ERE2, which are close to the transcription start site, and are associated with E2-mediated activation of HOXC13. Knockdown of the estrogen receptors (ERs) ERalpha and ERbeta suppressed E2-mediated activation of HOXC13. Similarly, knockdown of mixed lineage leukemia histone methylase (MLL)3 suppressed E2-induced activation of HOXC13. MLLs (MLL1-MLL4) were bound to the HOXC13 promoter in an E2-dependent manner. Knockdown of either ERalpha or ERbeta affected the E2-dependent binding of MLLs (MLL1-MLL4) into HOXC13 EREs, suggesting critical roles of ERs in recruiting MLLs in the HOXC13 promoter. Overall, our studies have demonstrated that HOXC13 is transcriptionally regulated by E2 and MLLs, which, in coordination with ERalpha and ERbeta, play critical roles in this process. Although MLLs are known to regulate HOX genes, the roles of MLLs in hormone-mediated regulation of HOX genes are unknown. Herein, we have demonstrated that MLLs are critical players in E2-dependent regulation of the HOX gene.

  16. Survivin plays as a resistant factor against tamoxifen-induced apoptosis in human breast cancer cells.

    Science.gov (United States)

    Moriai, Ryosuke; Tsuji, Naoki; Moriai, Mikako; Kobayashi, Daisuke; Watanabe, Naoki

    2009-09-01

    Tamoxifen has been the mainstay of endocrine therapy for estrogen receptor-positive breast cancer. However, approximately 40% of breast cancer patients do not respond to tamoxifen treatment. Further, most tumors eventually acquire tamoxifen resistance. Therefore, it is necessary to develop effective modalities to enhance the efficacy of tamoxifen in breast cancer treatment. In this study, we investigated the mechanism by which breast cancer cells develop resistance against tamoxifen from the viewpoint of tamoxifen-induced apoptosis. Overexpression of the anti-apoptotic molecule survivin rendered the human breast cancer cells MCF-7 resistant to tamoxifen-induced apoptosis. To examine whether the down-regulation of survivin can enhance tamoxifen-induced apoptosis, we introduced siRNA targeting the survivin gene (survivin-siRNA) into MCF-7 cells. Survivin-siRNA transfection not only induced apoptosis without tamoxifen treatment but also augmented the tamoxifen-induced apoptosis. We have previously demonstrated that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (HRIs), which are widely used to reduce the serum cholesterol levels in hypercholesterolemia patients, decreases survivin expression in colon cancer cells. To develop a pharmacological approach for improving the efficacy of tamoxifen treatment, we determined whether HRIs can enhance tamoxifen-induced apoptosis. Lovastatin, an HRI, down-regulated the expression of survivin protein in MCF-7 cells in a dose-dependent manner. In addition, the proportion of apoptotic cells induced by the tamoxifen and lovastatin combination was greater than the theoretical additive effect. These results suggest that survivin may function as a factor inducing resistance against tamoxifen-induced apoptosis, and the combined use of tamoxifen and HRI may be a novel approach to overcome tamoxifen resistance in breast cancer.

  17. Modulators of androgen and estrogen receptor activity.

    Science.gov (United States)

    Clarke, Bart L; Khosla, Sundeep

    2010-01-01

    This review focuses on significant recent findings regarding modulators of androgen and estrogen receptor activity. Selective androgen receptor modulators (SARMs) interact with androgen receptors (ARs), and selective estrogen receptor modulators (SERMs) interact with estrogen receptors (ERs), with variable tissue selectivity. SERMs, which interact with both ERб and ERв in a tissue-specific manner to produce diverse outcomes in multiple tissues, continue to generate significant interest for clinical application. Development of SARMs for clinical application has been slower to date because of potential adverse effects, but these diverse compounds continue to be investigated for use in disorders in which modulation of the AR is important. SARMs have been investigated mostly at the basic and preclinical level to date, with few human clinical trials published. These compounds have been evaluated mostly for application in different stages of prostate cancer to date, but they hold promise for multiple other applications. Publication of the large STAR and RUTH clinical trials demonstrated that the SERMs tamoxifen and raloxifene have interesting similarities and differences in tissues that contain ERs. Lasofoxifene, bazedoxifene, and arzoxifene are newer SERMs that have been demonstrated in clinical trials to more potently increase bone mineral density and lower serum cholesterol values than tamoxifen or raloxifene. Both SARMs and SERMs hold great promise for therapeutic use in multiple disorders in which tissue-specific effects are mediated by their respective receptors.

  18. Estrogen augments shear stress-induced signaling and gene expression in osteoblast-like cells via estrogen receptor-mediated expression of beta1-integrin.

    Science.gov (United States)

    Yeh, Chiuan-Ren; Chiu, Jeng-Jiann; Lee, Chih-I; Lee, Pei-Ling; Shih, Yu-Tsung; Sun, Jui-Sheng; Chien, Shu; Cheng, Cheng-Kung

    2010-03-01

    Estrogen and mechanical forces are positive regulators for osteoblast proliferation and bone formation. We investigated the synergistic effect of estrogen and flow-induced shear stress on signal transduction and gene expression in human osetoblast-like MG63 cells and primary osteoblasts (HOBs) using activations of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) and expressions of c-fos and cyclooxygenase-2 (I) as readouts. Estrogen (17beta-estradiol, 10 nM) and shear stress (12 dyn/cm(2)) alone induced transient phosphorylations of ERK and p38 MAPK in MG63 cells. Pretreating MG63 cells with 17beta-estradiol for 6 hours before shearing augmented these shear-induced MAPK phosphorylations. Western blot and flow cytometric analyses showed that treating MG63 cells with 17beta-estradiol for 6 hrs induced their beta(1)-integrin expression. This estrogen-induction of beta(1)-integrin was inhibited by pretreating the cells with a specific antagonist of estrogen receptor ICI 182,780. Both 17beta-estradiol and shear stress alone induced c-fos and Cox-2 gene expressions in MG63 cells. Pretreating MG63 cells with 17beta-estradiol for 6 hrs augmented the shear-induced c-fos and Cox-2 expressions. The augmented effects of 17beta-estradiol on shear-induced MAPK phosphorylations and c-fos and Cox-2 expressions were inhibited by pretreating the cells with ICI 182,780 or transfecting the cells with beta(1)-specific small interfering RNA. Similar results on the augmented effect of estrogen on shear-induced signaling and gene expression were obtained with HOBs. Our findings provide insights into the mechanism by which estrogen augments shear stress responsiveness of signal transduction and gene expression in bone cells via estrogen receptor-mediated increases in beta(1)-integrin expression. Copyright 2010 American Society for Bone and Mineral Research.

  19. Estrogen Augments Shear Stress–Induced Signaling and Gene Expression in Osteoblast-like Cells via Estrogen Receptor–Mediated Expression of β1-Integrin

    Science.gov (United States)

    Yeh, Chiuan-Ren; Chiu, Jeng-Jiann; Lee, Chih-I; Lee, Pei-Ling; Shih, Yu-Tsung; Sun, Jui-Sheng; Chien, Shu; Cheng, Cheng-Kung

    2010-01-01

    Estrogen and mechanical forces are positive regulators for osteoblast proliferation and bone formation. We investigated the synergistic effect of estrogen and flow-induced shear stress on signal transduction and gene expression in human osetoblast-like MG63 cells and primary osteoblasts (HOBs) using activations of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) and expressions of c-fos and cyclooxygenase-2 (I) as readouts. Estrogen (17β-estradiol, 10 nM) and shear stress (12 dyn/cm2) alone induced transient phosphorylations of ERK and p38 MAPK in MG63 cells. Pretreating MG63 cells with 17β-estradiol for 6 hours before shearing augmented these shear-induced MAPK phosphorylations. Western blot and flow cytometric analyses showed that treating MG63 cells with 17β-estradiol for 6 hrs induced their β1-integrin expression. This estrogen-induction of β1-integrin was inhibited by pretreating the cells with a specific antagonist of estrogen receptor ICI 182,780. Both 17β-estradiol and shear stress alone induced c-fos and Cox-2 gene expressions in MG63 cells. Pretreating MG63 cells with 17β-estradiol for 6 hrs augmented the shear-induced c-fos and Cox-2 expressions. The augmented effects of 17β-estradiol on shear-induced MAPK phosphorylations and c-fos and Cox-2 expressions were inhibited by pretreating the cells with ICI 182,780 or transfecting the cells with β1-specific small interfering RNA. Similar results on the augmented effect of estrogen on shear-induced signaling and gene expression were obtained with HOBs. Our findings provide insights into the mechanism by which estrogen augments shear stress responsiveness of signal transduction and gene expression in bone cells via estrogen receptor–mediated increases in β1-integrin expression. © 2010 American Society for Bone and Mineral Research. PMID:19821775

  20. Differential regulation of somatostatin receptors 1 and 2 mRNA and protein expression by tamoxifen and estradiol in breast cancer cells

    Directory of Open Access Journals (Sweden)

    Rivera Juan A

    2005-07-01

    Full Text Available Abstract Somatostatin (SST inhibition of hormone hypersecretion from tumors is mediated by somatostatin receptors (SSTRs. SSTRs also play an important role in controlling tumor growth through specific antiproliferative actions. These receptors are well expressed in numerous normal and tumor tissues and are susceptible to regulation by a variety of factors. Estradiol, a potent trophic and mitogenic hormone in its target tissues, is known to modulate the expression of SST and its receptors. Accordingly, in the present study, we determined the effects of tamoxifen, a selective estrogen receptor (ER modulator (SERM, and estradiol on SSTR1 and SSTR2 expression at the mRNA and protein levels in ER-positive and -negative breast cancer cells. We found that SSTR1 was upregulated by tamoxifen in a dose-dependent manner but no effect was seen with estradiol. In contrast, SSTR2 was upregulated by both tamoxifen and estradiol. Combined treatment caused suppression of SSTR1 below control levels but had no significant effect on SSTR2. Treatment with SSTR1-specific agonist was significantly more effective in suppressing cell proliferation of cells pre-treated with tamoxifen. Taking these data into consideration, we suggest that tamoxifen and estradiol exert variable effects on SSTR1 and SSTR2 mRNA and protein expression and distributional pattern of the receptors. These changes are cell subtype-specific and affect the ability of SSTR agonists to inhibit cell proliferation.

  1. Regulation of ERRalpha gene expression by estrogen receptor agonists and antagonists in SKBR3 breast cancer cells: differential molecular mechanisms mediated by g protein-coupled receptor GPR30/GPER-1.

    Science.gov (United States)

    Li, Yin; Birnbaumer, Lutz; Teng, Christina T

    2010-05-01

    In selected tissues and cell lines, 17beta-estradiol (E2) regulates the expression of estrogen-related receptor alpha (ERRalpha), a member of the orphan nuclear receptor family. This effect is thought to be mediated by the estrogen receptor alpha (ERalpha). However in the ERalpha- and ERbeta-negative SKBR3 breast cancer cell line, physiological levels of E2 also stimulate ERRalpha expression. Here, we explored the molecular mechanism that mediates estrogen action in ER-negative breast cancer cells. We observed that E2, the ERalpha agonist, as well as the ERalpha antagonists ICI 182,780 and tamoxifen (TAM), a selective ER modulator, stimulate the transcriptional activity of the ERRalpha gene and increase the production of ERRalpha protein in SKBR3 cells. Moreover, the ERRalpha downstream target genes expression and cellular proliferation are also increased. We show further that the G protein-coupled receptor GPR30/GPER-1 (GPER-1) mediates these effects. The GPER-1 specific ligand G-1 mimics the actions of E2, ICI 182,780, and TAM on ERRalpha expression, and changing the levels of GPER-1 mRNA by overexpression or small interfering RNA knockdown affected the expression of ERRalpha accordingly. Utilizing inhibitors, we delineate a different downstream pathway for ER agonist and ER antagonist-triggered signaling through GPER-1. We also find differential histone acetylation and transcription factor recruitment at distinct nucleosomes of the ERRalpha promoter, depending on whether the cells are activated with E2 or with ER antagonists. These findings provide insight into the molecular mechanisms of GPER-1/ERRalpha-mediated signaling and may be relevant to what happens in breast cancer cells escaping inhibitory control by TAM.

  2. Distinct hypothalamic neurons mediate estrogenic effects on energy homeostasis and reproduction.

    Science.gov (United States)

    Xu, Yong; Nedungadi, Thekkethil P; Zhu, Liangru; Sobhani, Nasim; Irani, Boman G; Davis, Kathryn E; Zhang, Xiaorui; Zou, Fang; Gent, Lana M; Hahner, Lisa D; Khan, Sohaib A; Elias, Carol F; Elmquist, Joel K; Clegg, Deborah J

    2011-10-05

    Estrogens regulate body weight and reproduction primarily through actions on estrogen receptor-α (ERα). However, ERα-expressing cells mediating these effects are not identified. We demonstrate that brain-specific deletion of ERα in female mice causes abdominal obesity stemming from both hyperphagia and hypometabolism. Hypometabolism and abdominal obesity, but not hyperphagia, are recapitulated in female mice lacking ERα in hypothalamic steroidogenic factor-1 (SF1) neurons. In contrast, deletion of ERα in hypothalamic pro-opiomelanocortin (POMC) neurons leads to hyperphagia, without directly influencing energy expenditure or fat distribution. Further, simultaneous deletion of ERα from both SF1 and POMC neurons causes hypometabolism, hyperphagia, and increased visceral adiposity. Additionally, female mice lacking ERα in SF1 neurons develop anovulation and infertility, while POMC-specific deletion of ERα inhibits negative feedback regulation of estrogens and impairs fertility in females. These results indicate that estrogens act on distinct hypothalamic ERα neurons to regulate different aspects of energy homeostasis and reproduction. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Cyclin G2 suppresses estrogen-mediated osteogenesis through inhibition of Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Jinlan Gao

    Full Text Available Estrogen plays an important role in the maintenance of bone formation, and deficiency in the production of estrogen is directly linked to postmenopausal osteoporosis. To date, the underlying mechanisms of estrogen-mediated osteogenic differentiation are not well understood. In this study, a pluripotent mesenchymal precursor cell line C2C12 was used to induce osteogenic differentiation and subjected to detection of gene expressions or to manipulation of cyclin G2 expressions. C57BL/6 mice were used to generate bilateral ovariectomized and sham-operated mice for analysis of bone mineral density and protein expression. We identified cyclin G2, an unconventional member of cyclin, is involved in osteoblast differentiation regulated by estrogen in vivo and in vitro. In addition, the data showed that ectopic expression of cyclin G2 suppressed expression of osteoblast transcription factor Runx2 and osteogenic differentiation marker genes, as well as ALP activity and in vitro extracellular matrix mineralization. Mechanistically, Wnt/β-catenin signaling pathway is essential for cyclin G2 to inhibit osteogenic differentiation. To the best of our knowledge, the current study presents the first evidence that cyclin G2 serves as a negative regulator of both osteogenesis and Wnt/β-catenin signaling. Most importantly, the basal and 17β-estradiol-induced osteogenic differentiation was restored by overexpression of cyclin G2. These results taken together suggest that cyclin G2 may function as an endogenous suppressor of estrogen-induced osteogenic differentiation through inhibition of Wnt/β-catenin signaling.

  4. New selective estrogen and androgen receptor modulators.

    Science.gov (United States)

    Clarke, Bart L; Khosla, Sundeep

    2009-07-01

    The present review focuses on the most significant recent findings regarding selective estrogen receptor modulators (SERMs) and selective androgen receptor modulators (SARMs). SERMs, which interact with estrogen receptor-alpha and estrogen receptor-beta in multiple tissues, continue to generate clinical interest in potential applications in as many disorders as the tissues in which the two known receptors are found. SARMs have been demonstrated to have fewer clinical applications to date, but continue to be investigated for use in multiple disorders in which androgen receptor modulation is likely to be important. Both types of compounds hold great promise for therapeutic use in multiple hormonal disorders involving tissue-specific effects mediated by estrogen or androgen receptors. Although SERMs have been available for clinical use for 50 years, recent investigation has focused on large randomized clinical trials for newer indications of older agents or smaller clinical trials of newer agents with improved clinical activity and reduced side effects in specific tissues. In particular, the large, prospective, randomized, controlled, multiyear Study of Tamoxifen and Raloxifene and Raloxifene Use in the Heart clinical trials have recently shown interesting similarities and differences between tamoxifen and raloxifene in estrogen-responsive tissues. Lasofoxifene and arzoxifene are two newer SERMs that have recently been demonstrated to improve bone mineral density and lower serum cholesterol values compared with older SERMs in smaller clinical trials. SARMs are a newer category of drug still being investigated mostly at the basic and preclinical level, with fewer clinical trials available for review. SARMs are currently being investigated mostly for use in prostate cancer at different stages but hold promise for multiple other applications. Recent clinical trials indicate that SERMs are useful in treatment of disorders of bone and mineral metabolism and breast cancer

  5. Tamoxifen-independent recombination in the RIP-CreER mouse.

    Directory of Open Access Journals (Sweden)

    Yanmei Liu

    Full Text Available BACKGROUND: The inducible Cre-lox system is a valuable tool to study gene function in a spatial and time restricted fashion in mouse models. This strategy relies on the limited background activity of the modified Cre recombinase (CreER in the absence of its inducer, the competitive estrogen receptor ligand, tamoxifen. The RIP-CreER mouse (Tg (Ins2-cre/Esr1 1Dam is among the few available β-cell specific CreER mouse lines and thus it has been often used to manipulate gene expression in the insulin-producing cells of the endocrine pancreas. PRINCIPAL FINDINGS: Here, we report the detection of tamoxifen-independent Cre activity as early as 2 months of age in RIP-CreER mice crossed with three distinct reporter strains. SIGNIFICANCE: Evidence of Cre-mediated recombination of floxed alleles even in the absence of tamoxifen administration should warrant cautious use of this mouse for the study of pancreatic β-cells.

  6. Estrogen receptor-mediated transcriptional activity of genistein in the mouse testis.

    Science.gov (United States)

    Montani, C; Penza, M; Jeremic, M; Rando, G; Ciana, P; Maggi, A; La Sala, G; De Felici, M; Di Lorenzo, D

    2009-04-01

    Here we show that genistein, through an estrogen receptor-mediated action, modulates gene expression in the mouse testis throughout development. Genistein passed from the lactating mother to the suckling offspring at levels sufficient to activate gene expression in the testis of the pups. Testis are already responsive to genistein as well as to estradiol at day 14.5 of fetal development. Activation of luciferase correlates with an activation of cell proliferation. In conclusion, our results show that genistein affects reproductive organs of male mice at all developmental ages.

  7. Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients: evidence for an estrogen surface receptor.

    Science.gov (United States)

    Stefano, G B; Prevot, V; Beauvillain, J C; Fimiani, C; Welters, I; Cadet, P; Breton, C; Pestel, J; Salzet, M; Bilfinger, T V

    1999-10-01

    We tested the hypothesis that estrogen acutely stimulates constitutive NO synthase (cNOS) activity in human peripheral monocytes by acting on an estrogen surface receptor. NO release was measured in real time with an amperometric probe. 17beta-estradiol exposure to monocytes stimulated NO release within seconds in a concentration-dependent manner, whereas 17alpha-estradiol had no effect. 17beta-estradiol conjugated to BSA (E2-BSA) also stimulated NO release, suggesting mediation by a membrane surface receptor. Tamoxifen, an estrogen receptor inhibitor, antagonized the action of both 17beta-estradiol and E2-BSA, whereas ICI 182,780, a selective inhibitor of the nuclear estrogen receptor, had no effect. We further showed, using a dual emission microfluorometry in a calcium-free medium, that the 17beta-estradiol-stimulated release of monocyte NO was dependent on the initial stimulation of intracellular calcium transients in a tamoxifen-sensitive process. Leeching out the intracellular calcium stores abolished the effect of 17beta-estradiol on NO release. RT-PCR analysis of RNA obtained from the cells revealed a strong estrogen receptor-alpha amplification signal and a weak beta signal. Taken together, a physiological dose of estrogen acutely stimulates NO release from human monocytes via the activation of an estrogen surface receptor that is coupled to increases in intracellular calcium.

  8. Estrogen receptor-mediated neuroprotection: The role of the Alzheimer’s disease-related gene seladin-1

    Directory of Open Access Journals (Sweden)

    Alessandro Peri

    2008-09-01

    Full Text Available Alessandro Peri, Mario SerioDepartment of Clinical Physiopathology, Endocrine Unit, Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies (DENOThe, University of Florence, Florence, ItalyAbstract: Experimental evidence supports a protective role of estrogen in the brain. According to the fact that Alzheimer’s disease (AD is more common in postmenopausal women, estrogen treatment has been proposed. However, there is no general consensus on the beneficial effect of estrogen or selective estrogen receptor modulators in preventing or treating AD. It has to be said that several factors may markedly affect the efficacy of the treatment. A few years ago, the seladin-1 gene (for selective Alzheimer’s disease indicator-1 has been isolated and found to be down-regulated in brain regions affected by AD. Seladin-1 has been found to be identical to the gene encoding the enzyme 3-beta-hydroxysterol delta-24-reductase, involved in the cholesterol biosynthetic pathway, which confers protection against β-amyloid-mediated toxicity and from oxidative stress, and is an effective inhibitor of caspase-3 activity, a key mediator of apoptosis. Interestingly, we found earlier that the expression of this gene is up-regulated by estrogen. Furthermore, our very recent data support the hypothesis that seladin-1 is a mediator of the neuroprotective effects of estrogen. This review will summarize the current knowledge regarding the neuroprotective effects of seladin-1 and the relationship between this protein and estrogen.Keywords: seladin-1, DHCR24, estrogen, brain, Alzheimer’s disease

  9. Tamoxifen- Induced Dermatomyositis

    Directory of Open Access Journals (Sweden)

    Bandyopadhyay Debabrata

    1997-01-01

    Full Text Available A 38 year old woman developed dermatomyositis after radical mastectomy and tamoxifen therapy for metastatic breast carcinoma. The possibility of the drug as the underlying cause of the connective tissue disease is discussed.

  10. The T61 human breast cancer xenograft: an experimental model of estrogen therapy of breast cancer

    DEFF Research Database (Denmark)

    Brunner, N; Spang-Thomsen, M; Cullen, K

    1996-01-01

    Endocrine therapy is one of the principal treatment modalities of breast cancer, both in an adjuvant setting and in advanced disease. The T61 breast cancer xenograft described here provides an experimental model of the effects of estrogen treatment at a molecular level. T61 is an estrogen receptor...... positive tumor which was originally derived from a T1N0M0 invasive ductal cancer and has been carried as a serially transplanted xenograft in nude mice. T61 is a hormone sensitive tumor whose growth is suppressed by both estrogen and tamoxifen, in contrast to other estrogen receptor positive tumors...... growth is also inhibited in animals treated with a monoclonal antibody which blocks binding of ligand to the IGF-I receptor, which mediates the mitogenic signal of bound IGF-II through autophosphorylation of its intracellular tyrosine kinase domain. These results demonstrate the utility of the T61 model...

  11. WNT4 mediates estrogen receptor signaling and endocrine resistance in invasive lobular carcinoma cell lines.

    Science.gov (United States)

    Sikora, Matthew J; Jacobsen, Britta M; Levine, Kevin; Chen, Jian; Davidson, Nancy E; Lee, Adrian V; Alexander, Caroline M; Oesterreich, Steffi

    2016-09-20

    critical role in estrogen-induced growth that may also mediate endocrine resistance. WNT4 signaling may represent a novel target to modulate endocrine response specifically for patients with ILC.

  12. The anticancer drug tamoxifen counteracts the pathology in a mouse model of duchenne muscular dystrophy.

    Science.gov (United States)

    Dorchies, Olivier M; Reutenauer-Patte, Julie; Dahmane, Elyes; Ismail, Heham M; Petermann, Olivier; Patthey- Vuadens, Ophélie; Comyn, Sophie A; Gayi, Elinam; Piacenza, Tony; Handa, Robert J; Décosterd, Laurent A; Ruegg, Urs T

    2013-02-01

    Duchenne muscular dystrophy (DMD) is a severe disorder characterized by progressive muscle wasting,respiratory and cardiac impairments, and premature death. No treatment exists so far, and the identification of active substances to fight DMD is urgently needed. We found that tamoxifen, a drug used to treat estrogen-dependent breast cancer, caused remarkable improvements of muscle force and of diaphragm and cardiac structure in the mdx(5Cv) mouse model of DMD. Oral tamoxifen treatment from 3 weeks of age for 15 months at a dose of 10 mg/kg/day stabilized myofiber membranes, normalized whole body force, and increased force production and resistance to repeated contractions of the triceps muscle above normal values. Tamoxifen improved the structure of leg muscles and diminished cardiac fibrosis by~ 50%. Tamoxifen also reduced fibrosis in the diaphragm, while increasing its thickness,myofiber count, and myofiber diameter, thereby augmenting by 72% the amount of contractile tissue available for respiratory function. Tamoxifen conferred a markedly slower phenotype to the muscles.Tamoxifen and its metabolites were present in nanomolar concentrations in plasma and muscles,suggesting signaling through high-affinity targets. Interestingly, the estrogen receptors ERa and ERb were several times more abundant in dystrophic than in normal muscles, and tamoxifen normalized the relative abundance of ERb isoforms. Our findings suggest that tamoxifen might be a useful therapy for DMD.

  13. Phytoestrogenic Activity of Blackcurrant Anthocyanins Is Partially Mediated through Estrogen Receptor Beta

    Directory of Open Access Journals (Sweden)

    Naoki Nanashima

    2017-12-01

    Full Text Available Phytoestrogens are plant compounds with estrogenic effects found in many foods. We have previously reported phytoestrogen activity of blackcurrant anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside, delphinidin-3-glucoside, and delphinidin-3-rutinoside via the estrogen receptor (ERα. In this study, we investigated the participation of ERβ in the phytoestrogen activity of these anthocyanins. Blackcurrant anthocyanin induced ERβ-mediated transcriptional activity, and the IC50 of ERβ was lower than that of ERα, indicating that blackcurrant anthocyanins have a higher binding affinity to ERβ. In silico docking analysis of cyanidin and delphinidin, the core portions of the compound that fits within the ligand-binding pocket of ERβ, showed that similarly to 17β-estradiol, hydrogen bonds formed with the ERβ residues Glu305, Arg346, and His475. No fitting placement of glucoside or rutinoside sugar chains within the ligand-binding pocket of ERβ-estradiol complex was detected. However, as the conformation of helices 3 and 12 in ERβ varies depending on the ligand, we suggest that the surrounding structure, including these helices, adopts a conformation capable of accommodating glucoside or rutinoside. Comparison of ERα and ERβ docking structures revealed that the selectivity for ERβ is higher than that for ERα, similar to genistein. These results show that blackcurrant anthocyanins exert phytoestrogen activity via ERβ.

  14. c-Jun/AP-1 overexpression reprograms ERα signaling related to tamoxifen response in ERα-positive breast cancer.

    Science.gov (United States)

    He, Huan; Sinha, Indranil; Fan, Rongrong; Haldosen, Lars-Arne; Yan, Feifei; Zhao, Chunyan; Dahlman-Wright, Karin

    2018-02-22

    A critical mechanism that has been proposed for transcription regulation by estrogen receptor α (ER) is the tethering of ER to DNA via other transcription factors, such as AP-1. However, genome-wide assessment of the overlap in chromatin binding repertoires of these two transcription factors has not been reported. Here, we show that the AP-1 transcription factor c-Jun interacts with ER and that c-Jun chromatin binding shows extensive overlap with ER binding at the global level. Further, we show that c-Jun overexpression reprograms ER chromatin binding and modulates ER-mediated gene regulation. Our data are consistent with a mechanism where estrogen/ER-dependent crosstalk with AP-1 at the transcriptional level is mediated through the tethering of ER to DNA bound AP-1. Additionally, in our system c-Jun overexpression causes reduced sensitivity to tamoxifen in ER+ breast cancer cells. Integrated cistrome, transcriptome, and clinical data reveal TGFBI as a candidate gene which may confer tamoxifen resistance by ER and AP-1 crosstalk. Further, we show that TGFBI expression is elevated in breast cancer compared to normal breast. Together, our data provide a novel genome-wide footprint of ER and AP-1 crosstalk and suggest AP-1 and TGFBI signaling as potential therapeutic targets in AP-1-overexpressing ER-positive breast tumors.

  15. Extranuclear ERα is associated with regression of T47D PKCα-overexpressing, tamoxifen-resistant breast cancer.

    Science.gov (United States)

    Perez White, Bethany; Molloy, Mary Ellen; Zhao, Huiping; Zhang, Yiyun; Tonetti, Debra A

    2013-05-01

    Prior to the introduction of tamoxifen, high dose estradiol was used to treat breast cancer patients with similar efficacy as tamoxifen, albeit with some undesirable side effects. There is renewed interest to utilize estradiol to treat endocrine resistant breast cancers, especially since findings from several preclinical models and clinical trials indicate that estradiol may be a rational second-line therapy in patients exhibiting resistance to tamoxifen and/or aromatase inhibitors. We and others reported that breast cancer patients bearing protein kinase C alpha (PKCα)- expressing tumors exhibit endocrine resistance and tumor aggressiveness. Our T47D:A18/PKCα preclinical model is tamoxifen-resistant, hormone-independent, yet is inhibited by 17β-estradiol (E2) in vivo. We previously reported that E2-induced T47D:A18/PKCα tumor regression requires extranuclear ERα and interaction with the extracellular matrix. T47D:A18/PKCα cells were grown in vitro using two-dimensional (2D) cell culture, three-dimensional (3D) Matrigel and in vivo by establishing xenografts in athymic mice. Immunofluoresence confocal microscopy and co-localization were applied to determine estrogen receptor alpha (ERα) subcellular localization. Co-immunoprecipitation and western blot were used to examine interaction of ERα with caveolin-1. We report that although T47D:A18/PKCα cells are cross-resistant to raloxifene in cell culture and in Matrigel, raloxifene induces regression of tamoxifen-resistant tumors. ERα rapidly translocates to extranuclear sites during T47D:A18/PKCα tumor regression in response to both raloxifene and E2, whereas ERα is primarily localized in the nucleus in proliferating tumors. E2 treatment induced complete tumor regression whereas cessation of raloxifene treatment resulted in tumor regrowth accompanied by re-localization of ERα to the nucleus. T47D:A18/neo tumors that do not overexpress PKCα maintain ERα in the nucleus during tamoxifen-mediated regression

  16. Generation of brain tumours in mice by Cre-mediated recombination of neural progenitors in situ with the tamoxifen metabolite endoxifen

    Directory of Open Access Journals (Sweden)

    Anna Benedykcinska

    2016-02-01

    Full Text Available Targeted cell- or region-specific gene recombination is widely used in the functional analysis of genes implicated in development and disease. In the brain, targeted gene recombination has become a mainstream approach to study neurodegeneration or tumorigenesis. The use of the Cre-loxP system to study tumorigenesis in the adult central nervous system (CNS can be limited, when the promoter (such as GFAP is also transiently expressed during development, which can result in the recombination of progenies of different lineages. Engineering of transgenic mice expressing Cre recombinase fused to a mutant of the human oestrogen receptor (ER allows the circumvention of transient developmental Cre expression by inducing recombination in the adult organism. The recombination of loxP sequences occurs only in the presence of tamoxifen. Systemic administration of tamoxifen can, however, exhibit toxicity and might also recombine unwanted cell populations if the promoter driving Cre expression is active at the time of tamoxifen administration. Here, we report that a single site-specific injection of an active derivative of tamoxifen successfully activates Cre recombinase and selectively recombines tumour suppressor genes in neural progenitor cells of the subventricular zone in mice, and we demonstrate its application in a model for the generation of intrinsic brain tumours.

  17. Generation of brain tumours in mice by Cre-mediated recombination of neural progenitors in situ with the tamoxifen metabolite endoxifen.

    Science.gov (United States)

    Benedykcinska, Anna; Ferreira, Andreia; Lau, Joanne; Broni, Jessica; Richard-Loendt, Angela; Henriquez, Nico V; Brandner, Sebastian

    2016-02-01

    Targeted cell- or region-specific gene recombination is widely used in the functional analysis of genes implicated in development and disease. In the brain, targeted gene recombination has become a mainstream approach to study neurodegeneration or tumorigenesis. The use of the Cre-loxP system to study tumorigenesis in the adult central nervous system (CNS) can be limited, when the promoter (such as GFAP) is also transiently expressed during development, which can result in the recombination of progenies of different lineages. Engineering of transgenic mice expressing Cre recombinase fused to a mutant of the human oestrogen receptor (ER) allows the circumvention of transient developmental Cre expression by inducing recombination in the adult organism. The recombination of loxP sequences occurs only in the presence of tamoxifen. Systemic administration of tamoxifen can, however, exhibit toxicity and might also recombine unwanted cell populations if the promoter driving Cre expression is active at the time of tamoxifen administration. Here, we report that a single site-specific injection of an active derivative of tamoxifen successfully activates Cre recombinase and selectively recombines tumour suppressor genes in neural progenitor cells of the subventricular zone in mice, and we demonstrate its application in a model for the generation of intrinsic brain tumours. © 2016. Published by The Company of Biologists Ltd.

  18. Estrogen receptor, Progesterone receptor, HER2 status and Ki67 index and responsiveness to adjuvant tamoxifen in postmenopausal high-risk breast cancer patients enrolled in the DBCG 77C trial

    DEFF Research Database (Denmark)

    Knoop, Ann; Lænkholm, Anne Vibeke; Jensen, M. B.

    2014-01-01

    BCRR and BCM in postmenopausal patients with ER positive breast cancers. The relative benefit from tamoxifen was not significantly different in luminal A and B subtypes. Funding: The Danish Breast Cancer Cooperative Group (DBCG) prepared the original protocol (DBCG 77C) and was the sponsor of the study....... Funding was not provided to the participating departments. The biomarker study was supported by grants from the Clinical Institute, Odense University. (C) 2014 Elsevier Ltd. All rights reserved....

  19. Rhodacyanine derivative selectively targets cancer cells and overcomes tamoxifen resistance.

    Directory of Open Access Journals (Sweden)

    John Koren

    Full Text Available MKT-077, a rhodacyanine dye, was shown to produce cancer specific cell death. However, complications prevented the use of this compound beyond clinical trials. Here we describe YM-1, a derivative of MKT-077. We found that YM-1 was more cytotoxic and localized differently than MKT-077. YM-1 demonstrated this cytotoxicity across multiple cancer cell lines. This toxicity was limited to cancer cell lines; immortalized cell models were unaffected. Brief applications of YM-1 were found to be non-toxic. Brief treatment with YM-1 restored tamoxifen sensitivity to a refractory tamoxifen-resistant MCF7 cell model. This effect is potentially due to altered estrogen receptor alpha phosphorylation, an outcome precipitated by selective reductions in Akt levels (Akt/PKB. Thus, modifications to the rhodocyanine scaffold could potentially be made to improve efficacy and pharmacokinetic properties. Moreover, the impact on tamoxifen sensitivity could be a new utility for this compound family.

  20. Proteomic Analysis of Estrogen-Mediated Signal Transduction in Osteoclasts Formation

    Directory of Open Access Journals (Sweden)

    Qi Xiong

    2015-01-01

    Full Text Available Estrogen plays an important role in inhibiting osteoclast differentiation and protecting against bone loss from osteoporosis, especially in postmenopausal women. However, the precise mechanisms underlying the effect of estrogen on osteoclasts are not well known. In the present study, we performed proteomics analysis and bioinformatics analysis to comprehensively compare the differential expression of proteins in receptor activator of nuclear factor-κB ligand RANKL-induced osteoclasts in the presence and absence of estrogen. We identified 6403 proteins, of which 124 were upregulated and 231 were downregulated by estrogen. Bioinformatics analysis showed that estrogen treatment interfered with 77 intracellular pathways, including both confirmed canonical and unconfirmed pathways of osteoclast formation. Our findings validate the inhibitory effect of estrogen on osteoclasts via the promotion of apoptosis and suppression of differentiation and polarization and suggest that estrogen might inhibit osteoclast formation via other pathways, which requires further investigation and verification.

  1. Malignant mixed Mullerian tumour of uterus secondary to tamoxifen therapy for hormone responsive breast cancer.

    Science.gov (United States)

    Gupta, Mayank; Kiruthiga, Kala Gnanasekaran

    2015-06-29

    Tamoxifen is used in the treatment of hormone responsive breast cancer because of its antiestrogenic effect. However, it also has an estrogenic effect on the uterus, thereby increasing the risk of endometrial hyperplasia, endometrial polyp and endometrial neoplasms such as endometrial adenocarcinoma and malignant mixed Mullerian tumour (MMMT). This case describes the possible pathogenesis and risk of developing MMMT due to long-term tamoxifen intake in hormone responsive breast cancer. 2015 BMJ Publishing Group Ltd.

  2. ER-α36-Mediated Rapid Estrogen Signaling Positively Regulates ER-Positive Breast Cancer Stem/Progenitor Cells

    Science.gov (United States)

    Deng, Hao; Zhang, Xin-Tian; Wang, Mo-Lin; Zheng, Hong-Yan; Liu, Li-Jiang; Wang, Zhao-Yi

    2014-01-01

    The breast cancer stem cells (BCSC) play important roles in breast cancer occurrence, recurrence and metastasis. However, the role of estrogen signaling, a signaling pathway important in development and progression of breast cancer, in regulation of BCSC has not been well established. Previously, we identified and cloned a variant of estrogen receptor α, ER-α36, with a molecular weight of 36 kDa. ER-α36 lacks both transactivation domains AF-1 and AF-2 of the 66 kDa full-length ER-α (ER-α66) and mediates rapid estrogen signaling to promote proliferation of breast cancer cells. In this study, we aim to investigate the function and the underlying mechanism of ER-α36-mediated rapid estrogen signaling in growth regulation of the ER-positive breast cancer stem/progenitor cells. ER-positive breast cancer cells MCF7 and T47D as well as the variants with different levels of ER-α36 expression were used. The effects of estrogen on BCSC's abilities of growth, self-renewal, differentiation and tumor-seeding were examined using tumorsphere formation, flow cytometry, indirect immunofluorence staining and in vivo xenograft assays. The underlying mechanisms were also studied with Western-blot analysis. We found that 17-β-estradiol (E2β) treatment increased the population of ER-positive breast cancer stem/progenitor cells while failed to do so in the cells with knocked-down levels of ER-α36 expression. Cells with forced expression of recombinant ER-α36, however, responded strongly to E2β treatment by increasing growth in vitro and tumor-seeding efficiency in vivo. The rapid estrogen signaling via the AKT/GSK3β pathway is involved in estrogen-stimulated growth of ER-positive breast cancer stem/progenitor cells. We concluded that ER-α36-mediated rapid estrogen signaling plays an important role in regulation and maintenance of ER-positive breast cancer stem/progenitor cells. PMID:24558373

  3. Mitochondrial p38β and manganese superoxide dismutase interaction mediated by estrogen in cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Han Liu

    Full Text Available While etiology behind the observed acceleration of ischemic heart disease in postmenopausal women is poorly understood, collective scientific data suggest cardioprotective effects of the endogenous female sex hormone, estrogen. We have previously shown that 17β-estradiol (E2 protects cardiomyocytes exposed to hypoxia-reoxygenation (H/R by inhibiting p38α - p53 signaling in apoptosis and activating pro-survival p38β mitogen activated protein kinase (p38β MAPK, leading to suppression of reactive oxygen species (ROS post H/R. However, little is known about the mechanism behind the antioxidant actions of E2-dependent p38β. The aim of this study is to determine whether the cytoprotection by estrogen involves regulation of manganese superoxide dismutase (MnSOD, a major mitochondrial ROS scavenging enzyme, via cardiac p38β.We identified mitochondrial p38β by immunocytochemistry and by immunoblotting in mitochondria isolated from neonatal cardiomyocytes of Sprague-Dawley rats. E2 facilitated the mitochondrial localization of the active form of the kinase, phosphorylated p38β (p-p38β. E2 also reduced the H/R-induced mitochondrial membrane potential decline, augmented the MnSOD activity and suppressed anion superoxide generation, while the dismutase protein expression remained unaltered. Co-immunoprecipitation studies showed physical association between MnSOD and p38β. p38β phosphorylated MnSOD in an E2-dependent manner in in-vitro kinase assays.This work demonstrates for the first time a mitochondrial pool of active p38β and E2-mediated phosphorylation of MnSOD by the kinase. The results shed light on the mechanism behind the cytoprotective actions of E2 in cardiomyocytes under oxidative stress.

  4. Effects on DHEA levels by estrogen in rat astrocytes and CNS co-cultures via the regulation of CYP7B1-mediated metabolism

    DEFF Research Database (Denmark)

    Fex Svenningsen, Åsa; Wicher, Grzegorz; Lundqvist, Johan

    2011-01-01

    in primary cultures of rat astrocytes. Interestingly, diarylpropionitrile, a well-known agonist of estrogen receptor β, also suppressed CYP7B1-mediated hydroxylation of DHEA. Several previous studies have reported neuroprotective effects of estrogens. The current data indicate that one of the mechanisms...

  5. ERα Mediates Estrogen-Induced Expression of the Breast Cancer Metastasis Suppressor Gene BRMS1

    Directory of Open Access Journals (Sweden)

    Hongtao Ma

    2016-01-01

    Full Text Available Recently, estrogen has been reported as putatively inhibiting cancer cell invasion and motility. This information is in direct contrast to the paradigm of estrogen as a tumor promoter. However, data suggests that the effects of estrogen are modulated by the receptor isoform with which it interacts. In order to gain a clearer understanding of the role of estrogen in potentially suppressing breast cancer metastasis, we investigated the regulation of estrogen and its receptor on the downstream target gene, breast cancer metastasis suppressor 1 (BRMS1 in MCF-7, SKBR3, TTU-1 and MDA-MB-231 breast cancer cells. Our results showed that estrogen increased the transcription and expression of BRMS1 in the ERα positive breast cancer cell line, MCF-7. Additionally, the ERα specific agonist PPT also induced the transcription and expression of BRMS1. However, the two remaining estrogen receptor (ER subtype agonists had no effect on BRMS1 expression. In order to further examine the influence of ERα on BRMS1 expression, ERα expression was knocked down using siRNA (siERα. Western blot analysis showed that siERα reduced estrogen-induced and PPT-induced BRMS1 expression. In summary, this study demonstrates estrogen, via its α receptor, positively regulates the expression of BRMS1, providing new insight into a potential inhibitory effect of estrogen on metastasis suppression.

  6. Growth inhibition in response to estrogen withdrawal and tamoxifen therapy of human breast cancer xenografts evaluated by in vivo 31P magnetic resonance spectroscopy, creatine kinase activity, and apoptotic index

    DEFF Research Database (Denmark)

    Kristensen, C A; Kristjansen, P E; Brünner, N

    1995-01-01

    index, and creatine kinase (CK) activity. Tumors of each line were grown in ovariectomized nude mice during stimulation from a s.c. 17 beta-estradiol pellet. At a tumor size of approximately 350 mm3, the pellet was removed from one-half of the animals. The remaining one-half served as controls...... indicate: (a) ZR75-1 and ZR75/LCC-3 xenografts respond differently to estrogen withdrawal and TAM with regard to growth inhibition, 31P magnetic resonance spectroscopy, and CK activity; (b) estrogen withdrawal, but not TAM, induced a decrease in the CK activity of estrogen-dependent tumor tissue, and (c...

  7. Modulators of estrogen receptor inhibit proliferation and migration of prostate cancer cells.

    Science.gov (United States)

    Piccolella, Margherita; Crippa, Valeria; Messi, Elio; Tetel, Marc J; Poletti, Angelo

    2014-01-01

    In the initial stages, human prostate cancer (PC) is an androgen-sensitive disease, which can be pharmacologically controlled by androgen blockade. This therapy often induces selection of androgen-independent PC cells with increased invasiveness. We recently demonstrated, both in cells and mice, that a testosterone metabolite locally synthetized in prostate, the 5α-androstane-3β, 17β-diol (3β-Adiol), inhibits PC cell proliferation, migration and invasion, acting as an anti-proliferative/anti-metastatic agent. 3β-Adiol is unable to bind androgen receptor (AR), but exerts its protection against PC by specifically interacting with estrogen receptor beta (ERβ). Because of its potential retro-conversion to androgenic steroids, 3β-Adiol cannot be used "in vivo", thus, the aims of this study were to investigate the capability of four ligands of ERβ (raloxifen, tamoxifen, genistein and curcumin) to counteract PC progression by mimicking the 3β-Adiol activity. Our results demonstrated that raloxifen, tamoxifen, genistein and curcumin decreased DU145 and PC3 cell proliferation in a dose-dependent manner; in addition, all four compounds significantly decreased the detachment of cells seeded on laminin or fibronectin. Moreover, raloxifen, tamoxifen, genistein and curcumin-treated DU145 and PC3 cells showed a significant decrease in cell migration. Notably, all these effects were reversed by the anti-estrogen, ICI 182,780, suggesting that their actions are mediated by the estrogenic pathway, via the ERβ, the only isoform present in these PCs. In conclusion, these data demonstrate that by selectively activating the ERβ, raloxifen, tamoxifen, genistein and curcumin inhibit human PC cells proliferation and migration favoring cell adesion. These synthetic and natural modulators of ER action may exert a potent protective activity against the progression of PC even in its androgen-independent status. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Androgen and estrogen receptor mediated mechanisms of testosterone action in male rat pelvic autonomic ganglia

    OpenAIRE

    Purves-Tyson, T.D.; Arshi, M.S.; Handelsman, D. J.; Cheng, Y.; Keast, J. R.

    2007-01-01

    Although male reproductive function is primarily androgen dependent, many studies suggest that estrogens have direct actions on the male reproductive organs. Pelvic autonomic neurons provide the motor control of the internal reproductive organs and the penis and various properties of these neurons are affected by endogenous androgens. However, the possible role of estrogens at this site has not been examined. Here we have investigated the significance of estrogens produced by aromatisation of...

  9. Estrogen-induced developmental disorders of the rat penis involve both estrogen receptor (ESR)- and androgen receptor (AR)-mediated pathways.

    Science.gov (United States)

    Goyal, H O; Braden, T D; Williams, C S; Williams, J W

    2009-09-01

    This study tested the hypothesis that the estrogen receptor (ESR) pathway, androgen receptor (AR) pathway, or both mediate estrogen-induced developmental penile disorders. Rat pups received diethylstilbestrol (DES), with or without the ESR antagonist ICI 182,780 (ICI) or the AR agonist dihydrotestosterone (DHT) or testosterone (T), from Postnatal Days 1 to 6. Testicular T concentration, penile morphology and morphometry, and/or fertility was determined at age 7, 28, or 150 days. DES treatment alone caused 90% reduction in the neonatal intratesticular T surge; this reduction was prevented by ICI coadministration, but not by DHT or T coadministration. Unlike the T surge, coadministration of ICI and coadministration of DHT or T mitigated penile deformities and loss of fertility. Generally, ICI, DHT, or T treatment alone did not alter penile morphology; however, fertility was 20% that of controls in ICI-treated rats vs. 70%-90% in DHT- or T-treated rats. The lower fertility in the rats treated with ICI alone could be due to altered sexual behavior, as these males did not deposit vaginal plugs. In conclusion, observations that both an ESR antagonist and AR agonists prevent penile deformities and infertility suggest that both pathways are involved in estrogen-induced penile disorders. Observations that coadministration of ICI, but not DHT or T, prevents the DES-induced reduction in the neonatal T surge suggest that, although ICI exerts its mitigating effect both at the level of Leydig cells and penile stromal cells, DHT and T do so only at the level of stromal cells.

  10. Estrogen-Induced Developmental Disorders of the Rat Penis Involve Both Estrogen Receptor (ESR)- and Androgen Receptor (AR)-Mediated Pathways1

    Science.gov (United States)

    Goyal, H.O.; Braden, T.D.; Williams, C.S.; Williams, J.W.

    2009-01-01

    This study tested the hypothesis that the estrogen receptor (ESR) pathway, androgen receptor (AR) pathway, or both mediate estrogen-induced developmental penile disorders. Rat pups received diethylstilbestrol (DES), with or without the ESR antagonist ICI 182,780 (ICI) or the AR agonist dihydrotestosterone (DHT) or testosterone (T), from Postnatal Days 1 to 6. Testicular T concentration, penile morphology and morphometry, and/or fertility was determined at age 7, 28, or 150 days. DES treatment alone caused 90% reduction in the neonatal intratesticular T surge; this reduction was prevented by ICI coadministration, but not by DHT or T coadministration. Unlike the T surge, coadministration of ICI and coadministration of DHT or T mitigated penile deformities and loss of fertility. Generally, ICI, DHT, or T treatment alone did not alter penile morphology; however, fertility was 20% that of controls in ICI-treated rats vs. 70%–90% in DHT- or T-treated rats. The lower fertility in the rats treated with ICI alone could be due to altered sexual behavior, as these males did not deposit vaginal plugs. In conclusion, observations that both an ESR antagonist and AR agonists prevent penile deformities and infertility suggest that both pathways are involved in estrogen-induced penile disorders. Observations that coadministration of ICI, but not DHT or T, prevents the DES-induced reduction in the neonatal T surge suggest that, although ICI exerts its mitigating effect both at the level of Leydig cells and penile stromal cells, DHT and T do so only at the level of stromal cells. PMID:19420389

  11. The Role of Clusterin in Estrogen Deprivation-Mediated Cell Death in Breast Cancer Cells

    National Research Council Canada - National Science Library

    Leskov, Konstantin

    2002-01-01

    .... The loss of estrogen receptor in C4:2W cells correlated with a higher level of nCLU protein, and concomitant low levels of Ku70 when compared to the parental estrogen-dependent T47D breast cancer cell line...

  12. Importance of Estrogenic Signaling and Its Mediated Receptors in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Kin-Mang Lau

    2016-08-01

    Full Text Available Prostate cancer (PCa treatment was first established by Huggins and Hodges in 1941, primarily described as androgen deprivation via interference of testicular androgen production. The disease remains incurable with relapse of hormone-refractory cancer after treatments. Epidemiological and clinical studies disclosed the importance of estrogens in PCa. Discovery of estrogen receptor ERβ prompted direct estrogenic actions, in conjunction with ERα, on PCa cells. Mechanistically, ERs upon ligand binding transactivate target genes at consensus genomic sites via interactions with various transcriptional co-regulators to mold estrogenic signaling. With animal models, Noble revealed estrogen dependencies of PCa, providing insight into potential uses of antiestrogens in the treatment. Subsequently, various clinical trials were conducted and molecular and functional consequences of antiestrogen treatment in PCa were delineated. Besides, estrogens can also trigger rapid non-genomic signaling responses initiated at the plasma membrane, at least partially via an orphan G-protein-coupled receptor GPR30. Activation of GPR30 significantly inhibited in vitro and in vivo PCa cell growth and the underlying mechanism was elucidated. Currently, molecular networks of estrogenic and antiestrogenic signaling via ERα, ERβ and GPR30 in PCa have not been fully deciphered. This crucial information could be beneficial to further developments of effective estrogen- and antiestrogen-based therapy for PCa patients.

  13. Long-term endometrial effects in postmenopausal women with early breast cancer participating in the Intergroup Exemestane Study (IES)--a randomised controlled trial of exemestane versus continued tamoxifen after 2-3 years tamoxifen.

    Science.gov (United States)

    Bertelli, G; Hall, E; Ireland, E; Snowdon, C F; Jassem, J; Drosik, K; Karnicka-Mlodkowska, H; Coombes, R C; Bliss, J M

    2010-03-01

    The antiestrogen tamoxifen may have partial estrogen-like effects on the postmenopausal uterus. Aromatase inhibitors (AIs) are increasingly used after initial tamoxifen in the adjuvant treatment of postmenopausal early breast cancer due to their mechanism of action: a potential benefit being a reduction of uterine abnormalities caused by tamoxifen. Sonographic uterine effects of the steroidal AI exemestane were studied in 219 women participating in the Intergroup Exemestane Study: a large trial in postmenopausal women with estrogen receptor-positive (or unknown) early breast cancer, disease free after 2-3 years of tamoxifen, randomly assigned to continue tamoxifen or switch to exemestane to complete 5 years adjuvant treatment. The primary end point was the proportion of patients with abnormal (> or =5 mm) endometrial thickness (ET) on transvaginal ultrasound 24 months after randomisation. The analysis included 183 patients. Two years after randomisation, the proportion of patients with abnormal ET was significantly lower in the exemestane compared with tamoxifen arm (36% versus 62%, respectively; P = 0.004). This difference emerged within 6 months of switching treatment (43.5% versus 65.2%, respectively; P = 0.01) and disappeared within 12 months of treatment completion (30.8% versus 34.7%, respectively; P = 0.67). Switching from tamoxifen to exemestane significantly reverses endometrial thickening associated with continued tamoxifen.

  14. Comparative study on transcriptional activity of 17 parabens mediated by estrogen receptor α and β and androgen receptor.

    Science.gov (United States)

    Watanabe, Yoko; Kojima, Hiroyuki; Takeuchi, Shinji; Uramaru, Naoto; Ohta, Shigeru; Kitamura, Shigeyuki

    2013-07-01

    The structure-activity relationships of parabens which are widely used as preservatives for transcriptional activities mediated by human estrogen receptor α (hERα), hERβ and androgen receptor (hAR) were investigated. Fourteen of 17 parabens exhibited hERα and/or hERβ agonistic activity at concentrations of ≤ 1 × 10(-5)M, whereas none of the 17 parabens showed AR agonistic or antagonistic activity. Among 12 parabens with linear alkyl chains ranging in length from C₁ to C₁₂, heptylparaben (C₇) and pentylparaben (C₅) showed the most potent ERα and ERβ agonistic activity in the order of 10(-7)M and 10(-8)M, respectively, and the activities decreased in a stepwise manner as the alkyl chain was shortened to C₁ or lengthened to C₁₂. Most parabens showing estrogenic activity exhibited ERβ-agonistic activity at lower concentrations than those inducing ERα-agonistic activity. The estrogenic activity of butylparaben was markedly decreased by incubation with rat liver microsomes, and the decrease of activity was blocked by a carboxylesterase inhibitor. These results indicate that parabens are selective agonists for ERβ over ERα; their interactions with ERα/β are dependent on the size and bulkiness of the alkyl groups; and they are metabolized by carboxylesterases, leading to attenuation of their estrogenic activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Bioanalytical methods for determination of tamoxifen and its phase I metabolites: A review

    International Nuclear Information System (INIS)

    Teunissen, S.F.; Rosing, H.; Schinkel, A.H.; Schellens, J.H.M.; Beijnen, J.H.

    2010-01-01

    The selective estrogen receptor modulator tamoxifen is used in the treatment of early and advanced breast cancer and in selected cases for breast cancer prevention in high-risk subjects. The cytochrome P450 enzyme system and flavin-containing monooxygenase are responsible for the extensive metabolism of tamoxifen into several phase I metabolites that vary in toxicity and potencies towards estrogen receptor (ER) alpha and ER beta. An extensive overview of publications on the determination of tamoxifen and its phase I metabolites in biological samples is presented. In these publications techniques were used such as capillary electrophoresis, liquid, gas and thin layer chromatography coupled with various detection techniques (mass spectrometry, ultraviolet or fluorescence detection, liquid scintillation counting and nuclear magnetic resonance spectroscopy). A trend is seen towards the use of liquid chromatography coupled to mass spectrometry (LC-MS). State-of-the-art LC-MS equipment allowed for identification of unknown metabolites and quantification of known metabolites reaching lower limit of quantification levels in the sub pg mL -1 range. Although tamoxifen is also metabolized into phase II metabolites, the number of publications reporting on phase II metabolism of tamoxifen is scarce. Therefore the focus of this review is on phase I metabolites of tamoxifen. We conclude that in the past decades tamoxifen metabolism has been studied extensively and numerous metabolites have been identified. Assays have been developed for both the identification and quantification of tamoxifen and its metabolites in an array of biological samples. This review can be used as a resource for method transfer and development of analytical methods used to support pharmacokinetic and pharmacodynamic studies of tamoxifen and its phase I metabolites.

  16. Bioanalytical methods for determination of tamoxifen and its phase I metabolites: A review

    Energy Technology Data Exchange (ETDEWEB)

    Teunissen, S.F., E-mail: Bas.Teunissen@slz.nl [Department of Pharmacy and Pharmacology, Slotervaart Hospital, The Netherlands Cancer Institute, Louwesweg 6, 1066 EC Amsterdam (Netherlands); Rosing, H. [Department of Pharmacy and Pharmacology, Slotervaart Hospital, The Netherlands Cancer Institute, Louwesweg 6, 1066 EC Amsterdam (Netherlands); Schinkel, A.H. [Division of Molecular Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam (Netherlands); Schellens, J.H.M. [Department of Medical Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam (Netherlands); Department of Pharmaceutical Sciences, Science Faculty, Utrecht University, Utrecht (Netherlands); Beijnen, J.H. [Department of Pharmacy and Pharmacology, Slotervaart Hospital, The Netherlands Cancer Institute, Louwesweg 6, 1066 EC Amsterdam (Netherlands); Department of Pharmaceutical Sciences, Science Faculty, Utrecht University, Utrecht (Netherlands)

    2010-12-17

    The selective estrogen receptor modulator tamoxifen is used in the treatment of early and advanced breast cancer and in selected cases for breast cancer prevention in high-risk subjects. The cytochrome P450 enzyme system and flavin-containing monooxygenase are responsible for the extensive metabolism of tamoxifen into several phase I metabolites that vary in toxicity and potencies towards estrogen receptor (ER) alpha and ER beta. An extensive overview of publications on the determination of tamoxifen and its phase I metabolites in biological samples is presented. In these publications techniques were used such as capillary electrophoresis, liquid, gas and thin layer chromatography coupled with various detection techniques (mass spectrometry, ultraviolet or fluorescence detection, liquid scintillation counting and nuclear magnetic resonance spectroscopy). A trend is seen towards the use of liquid chromatography coupled to mass spectrometry (LC-MS). State-of-the-art LC-MS equipment allowed for identification of unknown metabolites and quantification of known metabolites reaching lower limit of quantification levels in the sub pg mL{sup -1} range. Although tamoxifen is also metabolized into phase II metabolites, the number of publications reporting on phase II metabolism of tamoxifen is scarce. Therefore the focus of this review is on phase I metabolites of tamoxifen. We conclude that in the past decades tamoxifen metabolism has been studied extensively and numerous metabolites have been identified. Assays have been developed for both the identification and quantification of tamoxifen and its metabolites in an array of biological samples. This review can be used as a resource for method transfer and development of analytical methods used to support pharmacokinetic and pharmacodynamic studies of tamoxifen and its phase I metabolites.

  17. Modeling mixtures of environmental estrogens found in U.S. surface waters with an in vitro estrogen mediated transcriptionai activation assay (T47D-KBluc).

    Science.gov (United States)

    There is growing concern of exposure to fish, wildlife, and humans to water sources contaminated with estrogens and the potential impact on reproductive health. Environmental estrogens can come from various sources including concentrated animal feedlot operations (CAFO), municipa...

  18. Determining estrogenic activity in serum from ovariectomized rats treated with environmental compounds using an in vitro estrogen-mediated transcriptional activation assay (T47D-KBluc)

    Science.gov (United States)

    The use of cell-based assays to quantify low levels of estrogen in human serum is an accepted method. These assays are more sensitive but less specific than radioimmunoassays (RIA). Thus, we hypothesized that estrogen responsive T47D-KBluc cells would detect estrogenic activity i...

  19. BMI-1 Mediates Estrogen-Deficiency-Induced Bone Loss by Inhibiting Reactive Oxygen Species Accumulation and T Cell Activation.

    Science.gov (United States)

    Li, Jinbo; Wang, Qian; Yang, Renlei; Zhang, Jiaqi; Li, Xing; Zhou, Xichao; Miao, Dengshun

    2017-05-01

    Previous studies have shown that estrogen regulates bone homeostasis through regulatory effects on oxidative stress. However, it is unclear how estrogen deficiency triggers reactive oxygen species (ROS) accumulation. Recent studies provide evidence that the B lymphoma Mo-MLV insertion region 1 (BMI-1) plays a critical role in protection against oxidative stress and that this gene is directly regulated by estrogen via estrogen receptor (ER) at the transcriptional level. In this study, ovariectomized mice were given drinking water with/without antioxidant N-acetyl-cysteine (NAC, 1 mg/mL) supplementation, and compared with each other and with sham mice. Results showed that ovariectomy resulted in bone loss with increased osteoclast surface, increased ROS levels, T cell activation, and increased TNF and RANKL levels in serum and in CD4 T cells; NAC supplementation largely prevented these alterations. BMI-1 expression levels were dramatically downregulated in CD4 T cells from ovariectomized mice. We supplemented drinking water to BMI-1-deficient mice with/without NAC and compared them with each other and with wild-type (WT) mice. We found that BMI-1 deficiency mimicked alterations observed in ovariectomy whereas NAC supplementation reversed all alterations induced by BMI-1 deficiency. Because T cells are critical in mediating ovariectomy-induced bone loss, we further assessed whether BMI-1 overexpression in lymphocytes can protect against estrogen deficiency-induced osteoclastogenesis and bone loss by inhibiting oxidative stress, T cell activation, and RANKL production. When WT and Eμ-BMI-1 transgenic mice with BMI-1 specifically overexpressed in lymphocytes were ovariectomized and compared with each other and with WT sham mice, we found that BMI-1 overexpression in lymphocytes clearly reversed all alterations induced by ovariectomy. Results from this study indicate that estrogen deficiency downregulates BMI-1 and subsequently increases ROS, T cell activation, and

  20. Bradycardic effects mediated by activation of G protein-coupled estrogen receptor in rat nucleus ambiguus.

    Science.gov (United States)

    Brailoiu, G Cristina; Arterburn, Jeffrey B; Oprea, Tudor I; Chitravanshi, Vineet C; Brailoiu, Eugen

    2013-03-01

    The G protein-coupled estrogen receptor (GPER) has been identified in several brain regions, including cholinergic neurons of the nucleus ambiguus, which are critical for parasympathetic cardiac regulation. Using calcium imaging and electrophysiological techniques, microinjection into the nucleus ambiguus and blood pressure measurement, we examined the in vitro and in vivo effects of GPER activation in nucleus ambiguus neurons. A GPER selective agonist, G-1, produced a sustained increase in cytosolic Ca(2+) concentration in a concentration-dependent manner in retrogradely labelled cardiac vagal neurons of nucleus ambiguus. The increase in cytosolic Ca(2+) produced by G-1 was abolished by pretreatment with G36, a GPER antagonist. G-1 depolarized cultured cardiac vagal neurons of the nucleus ambiguus. The excitatory effect of G-1 was also identified by whole-cell visual patch-clamp recordings in nucleus ambiguus neurons, in medullary slices. To validate the physiological relevance of our in vitro studies, we carried out in vivo experiments. Microinjection of G-1 into the nucleus ambiguus elicited a decrease in heart rate; the effect was blocked by prior microinjection of G36. Systemic injection of G-1, in addition to a previously reported decrease in blood pressure, also reduced the heart rate. The G-1-induced bradycardia was prevented by systemic injection of atropine, a muscarinic antagonist, or by bilateral microinjection of G36 into the nucleus ambiguus. Our results indicate that GPER-mediated bradycardia occurs via activation of cardiac parasympathetic neurons of the nucleus ambiguus and support the involvement of the GPER in the modulation of cardiac vagal tone.

  1. Obesity Suppresses Estrogen Receptor Beta Expression in Breast Cancer Cells via a HER2-Mediated Pathway.

    Science.gov (United States)

    Bowers, Laura W; Wiese, Megan; Brenner, Andrew J; Rossi, Emily L; Tekmal, Rajeshwar R; Hursting, Stephen D; deGraffenried, Linda A

    2015-01-01

    Obesity is associated with a worse breast cancer prognosis, while greater breast tumor estrogen receptor beta (ERβ) expression is correlated with improved therapy response and survival. The objective of this study was to determine the impact of obesity on breast cancer cell ERβ expression, which is currently unknown. We utilized an in vitro model of obesity in which breast cancer cells were exposed to patient serum pooled by body mass index category (obese (OB): ≥30 kg/m2; normal weight (N): 18.5-24.9 kg/m2). Four human mammary tumor cell lines representing the major breast cancer subtypes (SKBR3, MCF-7, ZR75, MDA-MB-231) and mammary tumor cells from MMTV-neu mice were used. ERβ expression, assessed by qPCR and western blotting, was suppressed in the two HER2-overexpressing cell lines (SKBR3, MMTV-neu) following OB versus N sera exposure, but did not vary in the other cell lines. Expression of Bcl-2 and cyclin D1, two genes negatively regulated by ERβ, was elevated in SKBR3 cells following exposure to OB versus N sera, but this difference was eliminated when the ERβ gene was silenced with siRNA. Herceptin, a HER2 antagonist, and siRNA to HER2 were used to evaluate the role of HER2 in sera-induced ERβ modulation. SKBR3 cell treatment with OB sera plus Herceptin increased ERβ expression three-fold. Similar results were obtained when HER2 expression was silenced with siRNA. OB sera also promoted greater SKBR3 cell viability and growth, but this variance was not present when ERβ was silenced or the cells were modified to overexpress ERβ. Based on this data, we conclude that obesity-associated systemic factors suppress ERβ expression in breast cancer cells via a HER2-mediated pathway, leading to greater cell viability and growth. Elucidation of the mechanism(s) mediating this effect could provide important insights into how ERβ expression is regulated as well as how obesity promotes a more aggressive disease.

  2. Obesity Suppresses Estrogen Receptor Beta Expression in Breast Cancer Cells via a HER2-Mediated Pathway.

    Directory of Open Access Journals (Sweden)

    Laura W Bowers

    Full Text Available Obesity is associated with a worse breast cancer prognosis, while greater breast tumor estrogen receptor beta (ERβ expression is correlated with improved therapy response and survival. The objective of this study was to determine the impact of obesity on breast cancer cell ERβ expression, which is currently unknown. We utilized an in vitro model of obesity in which breast cancer cells were exposed to patient serum pooled by body mass index category (obese (OB: ≥30 kg/m2; normal weight (N: 18.5-24.9 kg/m2. Four human mammary tumor cell lines representing the major breast cancer subtypes (SKBR3, MCF-7, ZR75, MDA-MB-231 and mammary tumor cells from MMTV-neu mice were used. ERβ expression, assessed by qPCR and western blotting, was suppressed in the two HER2-overexpressing cell lines (SKBR3, MMTV-neu following OB versus N sera exposure, but did not vary in the other cell lines. Expression of Bcl-2 and cyclin D1, two genes negatively regulated by ERβ, was elevated in SKBR3 cells following exposure to OB versus N sera, but this difference was eliminated when the ERβ gene was silenced with siRNA. Herceptin, a HER2 antagonist, and siRNA to HER2 were used to evaluate the role of HER2 in sera-induced ERβ modulation. SKBR3 cell treatment with OB sera plus Herceptin increased ERβ expression three-fold. Similar results were obtained when HER2 expression was silenced with siRNA. OB sera also promoted greater SKBR3 cell viability and growth, but this variance was not present when ERβ was silenced or the cells were modified to overexpress ERβ. Based on this data, we conclude that obesity-associated systemic factors suppress ERβ expression in breast cancer cells via a HER2-mediated pathway, leading to greater cell viability and growth. Elucidation of the mechanism(s mediating this effect could provide important insights into how ERβ expression is regulated as well as how obesity promotes a more aggressive disease.

  3. Estrogenic Activities of Fatty Acids and a Sterol Isolated from Royal Jelly

    Directory of Open Access Journals (Sweden)

    Kazu-Michi Suzuki

    2008-01-01

    Full Text Available We have previously reported that royal jelly (RJ from honeybees (Apis mellifera has weak estrogenic activity mediated by interaction with estrogen receptors that leads to changes in gene expression and cell proliferation. In this study, we isolated four compounds from RJ that exhibit estrogenic activity as evaluated by a ligand-binding assay for the estrogen receptor (ER β. These compounds were identified as 10-hydroxy-trans-2-decenoic acid, 10-hydroxydecanoic acid, trans-2-decenoic acid and 24-methylenecholesterol. All these compounds inhibited binding of 17β-estradiol to ERβ, although more weakly than diethylstilbestrol or phytoestrogens. However, these compounds had little or no effect on the binding of 17β-estradiol to ERα. Expression assays suggested that these compounds activated ER, as evidenced by enhanced transcription of a reporter gene containing an estrogen-responsive element. Treatment of MCF-7 cells with these compounds enhanced their proliferation, but concomitant treatment with tamoxifen blocked this effect. Exposure of immature rats to these compounds by subcutaneous injection induced mild hypertrophy of the luminal epithelium of the uterus, but was not associated with an increase in uterine weight. These findings provide evidence that these compounds contribute to the estrogenic effect of RJ.

  4. Tamoxifen-induced acute pancreatitis – a case report

    Directory of Open Access Journals (Sweden)

    Rafał Czyżykowski

    2014-03-01

    Full Text Available Tamoxifen is a selective estrogen receptor modulator used for the treatment of oestrogen/progesterone receptor positive breast cancer. It has antagonistic or agonistic activity depending on the tissue location. Generally it causes mild and reversible side effects, however more serious ones including cardiovascular and thromboembolic adverse events, uterine cancer or acute pancreatitis can also occur. Tamoxifen, like oestrogens, increases the plasma level of TG and liver secretion of VLDL. Moreover, it inhibits the key enzymes of triglyceride metabolism. In this report we present a case of a 55-year-old woman with a history of a poorly controlled hypertriglyceridaemia diagnosed with breast cancer. She was treated with surgery and adjuvant chemotherapy, radiotherapy and hormonotherapy with tamoxifen. About three months after hormonal treatment, her triglyceride level increased. Five months later she developed an acute necrotic pancreatitis that required hospitalization. Her serum samples on admission were highly lipemic. An abdominal ultrasound showed no evidence of gallstones or dilation of the bile ducts. There was no history of alcohol abuse or abdominal trauma. Tamoxifen was suspected as a trigger factor for pancreatitis. After the drug withdrawal and administration of the conservative management the patient’s medical condition improved. Due to a postmenopausal status of the patient and no harmful effect on serum lipids, an adjuvant hormonotherapy with aromatase inhibitor was started.

  5. Tamoxifen induces regression of estradiol-induced mammary cancer in ACI.COP-Ept2 rat model

    OpenAIRE

    Ruhlen, Rachel L.; Willbrand, Dana M.; Besch-Williford, Cynthia L.; Ma, Lixin; Shull, James D.; Sauter, Edward R.

    2008-01-01

    The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5–7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonan...

  6. Regulation of DNA Damage Response by Estrogen Receptor β-Mediated Inhibition of Breast Cancer Associated Gene 2

    Directory of Open Access Journals (Sweden)

    Yuan-Hao Lee

    2015-04-01

    Full Text Available Accumulating evidence suggests that ubiquitin E3 ligases are involved in cancer development as their mutations correlate with genomic instability and genetic susceptibility to cancer. Despite significant findings of cancer-driving mutations in the BRCA1 gene, estrogen receptor (ER-positive breast cancers progress upon treatment with DNA damaging-cytotoxic therapies. In order to understand the underlying mechanism by which ER-positive breast cancer cells develop resistance to DNA damaging agents, we employed an estrogen receptor agonist, Erb-041, to increase the activity of ERβ and negatively regulate the expression and function of the estrogen receptor α (ERα in MCF-7 breast cancer cells. Upon Erb-041-mediated ERα down-regulation, the transcription of an ERα downstream effector, BCA2 (Breast Cancer Associated gene 2, correspondingly decreased. The ubiquitination of chromatin-bound BCA2 was induced by ultraviolet C (UVC irradiation but suppressed by Erb-041 pretreatment, resulting in a blunted DNA damage response. Upon BCA2 silencing, DNA double-stranded breaks increased with Rad51 up-regulation and ataxia telangiectasia mutated (ATM activation. Mechanistically, UV-induced BCA2 ubiquitination and chromatin binding were found to promote DNA damage response and repair via the interaction of BCA2 with ATM, γH2AX and Rad51. Taken together, this study suggests that Erb-041 potentiates BCA2 dissociation from chromatin and co-localization with Rad51, resulting in inhibition of homologous recombination repair.

  7. Polypoid endometriosis mimicking invasive cancer in an obese, postmenopausal tamoxifen user

    Directory of Open Access Journals (Sweden)

    William T. Jaegle

    2017-11-01

    Précis: Endometriosis is a benign estrogen dependent condition rarely problematic in a postmenopausal patient. Tamoxifen use in the setting of an obese patient may contribute to a proliferation of pre-existing endometriosis which resembles an aggressive late-stage gynecological malignancy.

  8. International Union of Basic and Clinical Pharmacology. XCVII. G Protein–Coupled Estrogen Receptor and Its Pharmacologic Modulators

    Science.gov (United States)

    2015-01-01

    Estrogens are critical mediators of multiple and diverse physiologic effects throughout the body in both sexes, including the reproductive, cardiovascular, endocrine, nervous, and immune systems. As such, alterations in estrogen function play important roles in many diseases and pathophysiological conditions (including cancer), exemplified by the lower prevalence of many diseases in premenopausal women. Estrogens mediate their effects through multiple cellular receptors, including the nuclear receptor family (ERα and ERβ) and the G protein–coupled receptor (GPCR) family (GPR30/G protein–coupled estrogen receptor [GPER]). Although both receptor families can initiate rapid cell signaling and transcriptional regulation, the nuclear receptors are traditionally associated with regulating gene expression, whereas GPCRs are recognized as mediating rapid cellular signaling. Estrogen-activated pathways are not only the target of multiple therapeutic agents (e.g., tamoxifen, fulvestrant, raloxifene, and aromatase inhibitors) but are also affected by a plethora of phyto- and xeno-estrogens (e.g., genistein, coumestrol, bisphenol A, dichlorodiphenyltrichloroethane). Because of the existence of multiple estrogen receptors with overlapping ligand specificities, expression patterns, and signaling pathways, the roles of the individual receptors with respect to the diverse array of endogenous and exogenous ligands have been challenging to ascertain. The identification of GPER-selective ligands however has led to a much greater understanding of the roles of this receptor in normal physiology and disease as well as its interactions with the classic estrogen receptors ERα and ERβ and their signaling pathways. In this review, we describe the history and characterization of GPER over the past 15 years focusing on the pharmacology of steroidal and nonsteroidal compounds that have been employed to unravel the biology of this most recently recognized estrogen receptor. PMID

  9. Alcohol consumption negates estrogen-mediated myocardial repair in ovariectomized mice by inhibiting endothelial progenitor cell mobilization and function.

    Science.gov (United States)

    Mackie, Alexander R; Krishnamurthy, Prasanna; Verma, Suresh K; Thorne, Tina; Ramirez, Veronica; Qin, Gangjian; Abramova, Tatiana; Hamada, Hiromichi; Losordo, Douglas W; Kishore, Raj

    2013-06-21

    We have shown previously that estrogen (estradiol, E2) supplementation enhances voluntary alcohol consumption in ovariectomized female rodents and that increased alcohol consumption impairs ischemic hind limb vascular repair. However, the effect of E2-induced alcohol consumption on post-infarct myocardial repair and on the phenotypic/functional properties of endothelial progenitor cells (EPCs) is not known. Additionally, the molecular signaling of alcohol-estrogen interactions remains to be elucidated. This study examined the effect of E2-induced increases in ethanol consumption on post-infarct myocardial function/repair. Ovariectomized female mice, implanted with 17β-E2 or placebo pellets were given access to alcohol for 6 weeks and subjected to acute myocardial infarction. Left ventricular functions were consistently depressed in mice consuming ethanol compared with those receiving only E2. Alcohol-consuming mice also displayed significantly increased infarct size and reduced capillary density. Ethanol consumption also reduced E2-induced mobilization and homing of EPCs to injured myocardium compared with the E2-alone group. In vitro, exposure of EPCs to ethanol suppressed E2-induced proliferation, survival, and migration and markedly altered E2-induced estrogen receptor-dependent cell survival signaling and gene expression. Furthermore, ethanol-mediated suppression of EPC biology was endothelial nitric oxide synthase-dependent because endothelial nitric oxide synthase-null mice displayed an exaggerated response to post-acute myocardial infarction left ventricular functions. These data suggest that E2 modulation of alcohol consumption, and the ensuing EPC dysfunction, may negatively compete with the beneficial effects of estrogen on post-infarct myocardial repair.

  10. Mechanisms of G Protein-Coupled Estrogen Receptor-Mediated Spinal Nociception

    DEFF Research Database (Denmark)

    Deliu, Elena; Brailoiu, G. Cristina; Arterburn, Jeffrey B.

    2012-01-01

    Human and animal studies suggest that estrogens are involved in the processing of nociceptive sensory information and analgesic responses in the central nervous system. Rapid pronociceptive estrogenic effects have been reported, some of which likely involve G protein-coupled estrogen receptor (GPER...... in spinal nociceptive processing. Intrathecal challenging of mice with the GPER agonist G-1 results in pain-related behaviors. GPER antagonism with G15 reduces the G-1-induced response. Electrophysiological recordings from superficial dorsal horn neurons indicate neuronal membrane depolarization with G-1...... application, which is G15 sensitive. In cultured spinal sensory neurons, G-1 increases intracellular calcium concentration and induces mitochondrial and cytosolic ROS accumulation. In the presence of G15, G-1 does not elicit the calcium and ROS responses, confirming specific GPER involvement in this process...

  11. Expansion of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor Function in Normal and Cancer Cells: From Membrane Restructuring to Mediation of Estrogen Signaling and Stem Cell Programming.

    Science.gov (United States)

    Sukocheva, Olga A

    2018-01-31

    Sphingolipids, sphingolipid metabolizing enzymes, and their receptors network are being recognized as part of the signaling mechanisms, which govern breast cancer cell growth, migration, and survival during chemotherapy treatment. Approximately 70% of breast cancers are estrogen receptor (ER) positive and, thus, rely on estrogen signaling. Estrogen activates an intracellular network composed of many cytoplasmic and nuclear mediators. Some estrogen effects can be mediated by sphingolipids. Estrogen activates sphingosine kinase 1 (SphK1) and amplifies the intracellular concentration of sphingosine-1-phosphate (S1P) in breast cancer cells during stimulation of proliferation and survival. Specifically, Estrogen activates S1P receptors (S1PR) and induces growth factor receptor transactivation. SphK, S1P, and S1PR expression are causally associated with endocrine resistance and progression to advanced tumor stages in ER-positive breast cancers in vivo . Recently, the network of SphK/S1PR was shown to promote the development of ER-negative cancers and breast cancer stem cells, as well as stimulating angiogenesis. Novel findings confirm and broaden our knowledge about the cross-talk between sphingolipids and estrogen network in normal and malignant cells. Current S1PRs therapeutic inhibition was indicated as a promising chemotherapy approach in non-responsive and advanced malignancies. Considering that sphingolipid signaling has a prominent role in terminally differentiated cells, the impact should be considered when designing specific SphK/S1PR inhibitors. This study analyzes the dynamic of the transformation of sphingolipid axis during a transition from normal to pathological condition on the level of the whole organism. The sphingolipid-based mediation and facilitation of global effects of estrogen were critically accented as a bridging mechanism that should be explored in cancer prevention.

  12. Expansion of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor Function in Normal and Cancer Cells: From Membrane Restructuring to Mediation of Estrogen Signaling and Stem Cell Programming

    Directory of Open Access Journals (Sweden)

    Olga A. Sukocheva

    2018-01-01

    Full Text Available Sphingolipids, sphingolipid metabolizing enzymes, and their receptors network are being recognized as part of the signaling mechanisms, which govern breast cancer cell growth, migration, and survival during chemotherapy treatment. Approximately 70% of breast cancers are estrogen receptor (ER positive and, thus, rely on estrogen signaling. Estrogen activates an intracellular network composed of many cytoplasmic and nuclear mediators. Some estrogen effects can be mediated by sphingolipids. Estrogen activates sphingosine kinase 1 (SphK1 and amplifies the intracellular concentration of sphingosine-1-phosphate (S1P in breast cancer cells during stimulation of proliferation and survival. Specifically, Estrogen activates S1P receptors (S1PR and induces growth factor receptor transactivation. SphK, S1P, and S1PR expression are causally associated with endocrine resistance and progression to advanced tumor stages in ER-positive breast cancers in vivo. Recently, the network of SphK/S1PR was shown to promote the development of ER-negative cancers and breast cancer stem cells, as well as stimulating angiogenesis. Novel findings confirm and broaden our knowledge about the cross-talk between sphingolipids and estrogen network in normal and malignant cells. Current S1PRs therapeutic inhibition was indicated as a promising chemotherapy approach in non-responsive and advanced malignancies. Considering that sphingolipid signaling has a prominent role in terminally differentiated cells, the impact should be considered when designing specific SphK/S1PR inhibitors. This study analyzes the dynamic of the transformation of sphingolipid axis during a transition from normal to pathological condition on the level of the whole organism. The sphingolipid-based mediation and facilitation of global effects of estrogen were critically accented as a bridging mechanism that should be explored in cancer prevention.

  13. Lipidosis induced in rat uteri by high doses of tamoxifen.

    Science.gov (United States)

    Ioannidis, N

    1998-08-01

    The anti-estrogenic drug tamoxifen is an amphiphilic cationic compound and might therefore be expected to interfere with intralysosomal catabolism of polar lipids as has been previously reported with several other amphiphilic cationic drugs. The purpose of this study was to investigate whether there is lipidosis induction in the uterus. High oral doses of tamoxifen (100 mg/kg) were administered to 9 adult rats for 6-14 weeks. Their uteri were examined by light and electron microscopy. Lipidosis-like alterations were seen in the glandular epithelia and in the myometrium. The luminal epithelium was most severely affected. The highest degree of intraepithelial change was already observed after a short-term treatment (6 weeks). The results support the previously proposed concept of a relationship between the amphiphilic cationic character of a compound and its ability to cause intralysosomal storage of polar lipids after a high dosage treatment of these drugs in animals.

  14. Estrogen regulates the expression of cathepsin E-A-like gene via ...

    Indian Academy of Sciences (India)

    徐春林

    1College of Animal Science and Veterinary Medicine, Henan Agricultural University,. Zhengzhou ... combined with estrogen receptor antagonists including MPP, ICI 182,780 and tamoxifen. Our results showed that .... The ICI 182,780 and tamoxifen are antagonists of both ERα and ERβ, but may also act as the agonists of.

  15. The role of estrogen in bipolar disorder, a review

    DEFF Research Database (Denmark)

    Meinhard, Ninja; Kessing, Lars Vedel; Vinberg, Maj

    2014-01-01

    BACKGROUND: It appears that the female reproductive events and hormonal treatments may impact the course of bipolar disorder in women. In particular, childbirth is known to be associated with onset of affective episodes in women with bipolar disorder. During the female reproductive events the sex...... estrogen levels and women with bipolar disorder including studies of the anti manic effects of the selective estrogen receptor modulator tamoxifen. METHOD: A systematically literature search on PubMed was conducted: two studies regarding the connection between serum estrogen levels and women with bipolar...... disorder were identified. Furthermore, four studies were found concerning the antimanic effects of tamoxifen. RESULTS: Both studies in the estrogen studies showed very low levels of estrogen in women with postpartum psychosis and significant improvement of symptoms after treatment with estrogen. The four...

  16. The role of estrogen in bipolar disorder, a review

    DEFF Research Database (Denmark)

    Meinhard, Ninja; Kessing, Lars Vedel; Vinberg, Maj

    2014-01-01

    Background: It appears that the female reproductive events and hormonal treatments may impact the course of bipolar disorder in women. In particular, childbirth is known to be associated with onset of affective episodes in women with bipolar disorder. During the female reproductive events the sex...... estrogen levels and women with bipolar disorder including studies of the anti manic effects of the selective estrogen receptor modulator tamoxifen. Method: A systematically literature search on PubMed was conducted: two studies regarding the connection between serum estrogen levels and women with bipolar...... disorder were identified. Furthermore, four studies were found concerning the antimanic effects of tamoxifen. Results: Both studies in the estrogen studies showed very low levels of estrogen in women with postpartum psychosis and significant improvement of symptoms after treatment with estrogen. The four...

  17. Excellent outcomes with adjuvant toremifene or tamoxifen in early stage breast cancer

    Directory of Open Access Journals (Sweden)

    Jaime D. Lewis

    2014-01-01

    Full Text Available Fareston (toremifene and tamoxifen, both selective estrogen receptor modulators, are therapeutically equivalent treatments for metastatic breast cancer. We hypothesized that toremifene as compared with tamoxifen given as adjuvant therapy for early stage breast cancer would result in equivalent survival with an improved side effect profile, therefore, providing superior therapeutic efficacy.Subjects and methods. The North American Fareston versus Tamoxifen Adjuvant trial assigned 1813 perimenopausal or postmenopausal women with hormone receptor (HR – positive invasive breast cancer to adjuvant treatment with either tamoxifen or toremifene. The primary outcomes evaluated were disease-free survival (DFS and overall survival (OS.Results. Median follow-up was 59 months. The baseline characteristics of the 2 treatment groups were well-balanced. On the basis of intenttotreat, 5-year actuarial DFS was not significantly different between tamoxifen and toremifene (91.2 % (standard error of the mean (SE 1.2 % vs 91.2 % (SE 1.1 %, respectively. Similarly, 5-year actuarial OS was not significantly different between tamoxifen and toremifene (92.7 % (SE 1.1 % vs 93.7 % (SE 1.0 %, respectively. Controlling for patient age, tumor size, and tumor grade, a Cox multivariate survival analysis found no difference between patients randomized to toremifene versus tamoxifen in terms of OS (OR 0.951; 95 % confidence interval (CI, 0.623–1.451, p = 0.951 or DFS (OR 1.037; 95 % CI, 0.721–1.491, p = 0.846. Adverse events were similar in the 2 groups.Conclusions. Women treated with adjuvant hormonal therapy enjoyed excellent DFS and OS. No significant differences were found between treatment with either tamoxifen or toremifene. Treatment of HR-positive patients with either tamoxifen or toremifene is appropriate.

  18. Tanshinone IIA Prevents Leu27IGF-II-Induced Cardiomyocyte Hypertrophy Mediated by Estrogen Receptor and Subsequent Akt Activation.

    Science.gov (United States)

    Weng, Yueh-Shan; Wang, Hsueh-Fang; Pai, Pei-Ying; Jong, Gwo-Ping; Lai, Chao-Hung; Chung, Li-Chin; Hsieh, Dennis Jine-Yuan; HsuanDay, Cecilia; Kuo, Wei-Wen; Huang, Chih-Yang

    2015-01-01

    IGF-IIR plays important roles as a key regulator in myocardial pathological hypertrophy and apoptosis, which subsequently lead to heart failure. Salvia miltiorrhiza Bunge (Danshen) is a traditional Chinese medicinal herb used to treat cardiovascular diseases. Tanshinone IIA is an active compound in Danshen and is structurally similar to 17[Formula: see text]-estradiol (E[Formula: see text]. However, whether tanshinone IIA improves cardiomyocyte survival in pathological hypertrophy through estrogen receptor (ER) regulation remains unclear. This study investigates the role of ER signaling in mediating the protective effects of tanshinone IIA on IGF-IIR-induced myocardial hypertrophy. Leu27IGF-II (IGF-II analog) was shown in this study to specifically activate IGF-IIR expression and ICI 182,780 (ICI), an ER antagonist used to investigate tanshinone IIA estrogenic activity. We demonstrated that tanshinone IIA significantly enhanced Akt phosphorylation through ER activation to inhibit Leu27IGF-II-induced calcineurin expression and subsequent NFATc3 nuclear translocation to suppress myocardial hypertrophy. Tanshinone IIA reduced the cell size and suppressed ANP and BNP, inhibiting antihypertrophic effects induced by Leu27IGF-II. The cardioprotective properties of tanshinone IIA that inhibit Leu27IGF-II-induced cell hypertrophy and promote cell survival were reversed by ICI. Furthermore, ICI significantly reduced phospho-Akt, Ly294002 (PI3K inhibitor), and PI3K siRNA significantly reduced the tanshinone IIA-induced protective effect. The above results suggest that tanshinone IIA inhibited cardiomyocyte hypertrophy, which was mediated through ER, by activating the PI3K/Akt pathway and inhibiting Leu27IGF-II-induced calcineurin and NFATC3. Tanshinone IIA exerted strong estrogenic activity and therefore represented a novel selective ER modulator that inhibits IGF-IIR signaling to block cardiac hypertrophy.

  19. Aging negatively affects estrogens-mediated effects on nitric oxide bioavailability by shifting ERα/ERβ balance in female mice.

    Directory of Open Access Journals (Sweden)

    Laura Novensà

    Full Text Available AIMS: Aging is among the major causes for the lack of cardiovascular protection by estrogen (E2 during postmenopause. Our study aims to determine the mechanisms whereby aging changes E2 effects on nitric oxide (NO production in a mouse model of accelerated senescence (SAM. METHODS AND RESULTS: Although we found no differences on NO production in females SAM prone (SAMP, aged compared to SAM resistant (SAMR, young, by either DAF-2 fluorescence or plasmatic nitrite/nitrate (NO2/NO3, in both cases, E2 treatment increased NO production in SAMR but had no effect in SAMP. Those results are in agreement with changes of eNOS protein and gene expression. E2 up-regulated eNOS expression in SAMR but not in SAMP. E2 is also known to increase NO by decreasing its catabolism by superoxide anion (O(2(-. Interestingly, E2 treatment decreased O(2(- production in young females, while increased O(2(- in aged ones. Furthermore, we observed that aging changed expression ratio of estrogen receptors (ERβ/ERα and levels of DNA methylation. Increased ratio ERβ/ERα in aged females is associated to a lack of estrogen modulation of NO production and with a reversal in its antioxidant effect to a pro-oxidant profile. CONCLUSIONS: Together, our data suggest that aging has detrimental effects on E2-mediated benefits on NO bioavailability, partially by affecting the ability of E2 to induce up regulation of eNOS and decrease of O(2(-. These modifications may be associated to aging-mediated modifications on global DNA methylation status, but not to a specific methylation at 5'flanking region of ERα gene.

  20. Estrogenic mediation of serotonergic and neurotrophic systems: implications for female mood disorders.

    Science.gov (United States)

    Borrow, Amanda P; Cameron, Nicole M

    2014-10-03

    Clinical research has demonstrated a significant sex difference in the occurrence of depressive disorders. Beginning at pubertal onset, women report a higher incidence of depression than men. Women are also vulnerable to the development of depressive disorders such as premenstrual dysphoric disorder, postpartum depression, and perimenopausal depression. These disorders are associated with reproductive stages involving changes in gonadal hormone levels. Specifically, female depression and female affective behaviors are influenced by estradiol levels. This review argues two major mechanisms by which estrogens influence depression and depressive-like behavior: through interactions with neurotrophic factors and through an influence on the serotonergic system. In particular, estradiol increases brain derived neurotrophic factor (BDNF) levels within the brain, and alters serotonergic expression in a receptor subtype-specific manner. We will take a regional approach, examining these effects of estrogens in the major brain areas implicated in depression. Finally, we will discuss the gaps in our current knowledge of the effects of estrogens on female depression, and the potential utility for estrogen receptor modulators in treatment for this disorder. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Estrogen-mediated downregulation of AIRE influences sexual dimorphism in autoimmune diseases

    Science.gov (United States)

    Dragin, Nadine; Bismuth, Jacky; Cizeron-Clairac, Géraldine; Biferi, Maria Grazia; Berthault, Claire; Serraf, Alain; Nottin, Rémi; Klatzmann, David; Cumano, Ana; Barkats, Martine; Le Panse, Rozen

    2016-01-01

    Autoimmune diseases affect 5% to 8% of the population, and females are more susceptible to these diseases than males. Here, we analyzed human thymic transcriptome and revealed sex-associated differences in the expression of tissue-specific antigens that are controlled by the autoimmune regulator (AIRE), a key factor in central tolerance. We hypothesized that the level of AIRE is linked to sexual dimorphism susceptibility to autoimmune diseases. In human and mouse thymus, females expressed less AIRE (mRNA and protein) than males after puberty. These results were confirmed in purified murine thymic epithelial cells (TECs). We also demonstrated that AIRE expression is related to sexual hormones, as male castration decreased AIRE thymic expression and estrogen receptor α–deficient mice did not show a sex disparity for AIRE expression. Moreover, estrogen treatment resulted in downregulation of AIRE expression in cultured human TECs, human thymic tissue grafted to immunodeficient mice, and murine fetal thymus organ cultures. AIRE levels in human thymus grafted in immunodeficient mice depended upon the sex of the recipient. Estrogen also upregulated the number of methylated CpG sites in the AIRE promoter. Together, our results indicate that in females, estrogen induces epigenetic changes in the AIRE gene, leading to reduced AIRE expression under a threshold that increases female susceptibility to autoimmune diseases. PMID:26999605

  2. Estrogen-Cholinergic Interactions: Implications for Cognitive Aging

    Science.gov (United States)

    Newhouse, Paul; Dumas, Julie

    2015-01-01

    While many studies in humans have investigated the effects of estrogen and hormone therapy on cognition, potential neurobiological correlates of these effects have been less well studied. An important site of action for estrogen in the brain is the cholinergic system. Several decades of research support the critical role of CNS cholinergic systems in cognition in humans, particularly in learning and memory formation and attention. In humans, the cholinergic system has been implicated in many aspects of cognition including the partitioning of attentional resources, working memory, inhibition of irrelevant information, and improved performance on effort-demanding tasks. Studies support the hypothesis that estradiol helps to maintain aspects of attention and verbal and visual memory. Such cognitive domains are exactly those modulated by cholinergic systems and extensive basic and preclinical work over the past several decades has clearly shown that basal forebrain cholinergic systems are dependent on estradiol support for adequate functioning. This paper will review recent human studies from our laboratories and others that have extended preclinical research examining estrogen-cholinergic interactions to humans. Studies examined include estradiol and cholinergic antagonist reversal studies in normal older women, examinations of the neural representations of estrogen-cholinergic interactions using functional brain imaging, and studies of the ability of selective estrogen receptor modulators such as tamoxifen to interact with cholinergic-mediated cognitive performance. We also discuss the implications of these studies for the underlying hypotheses of cholinergic-estrogen interactions and cognitive aging, and indications for prophylactic and therapeutic potential that may exploit these effects. PMID:26187712

  3. Novel Growth Factor as Prognostic Marker for Estrogen-Independence in Breast Cancer

    National Research Council Canada - National Science Library

    Serrero, Ginette

    2003-01-01

    The Concept Award focused on investigating the expression on the biomarker PCDGF/GP88 in breast cancer and its effect on the acquisition of estrogen independence and tamoxifen resistance, a hallmark...

  4. Progesterone receptor isoforms, agonists and antagonists differentially reprogram estrogen signaling.

    Science.gov (United States)

    Singhal, Hari; Greene, Marianne E; Zarnke, Allison L; Laine, Muriel; Al Abosy, Rose; Chang, Ya-Fang; Dembo, Anna G; Schoenfelt, Kelly; Vadhi, Raga; Qiu, Xintao; Rao, Prakash; Santhamma, Bindu; Nair, Hareesh B; Nickisch, Klaus J; Long, Henry W; Becker, Lev; Brown, Myles; Greene, Geoffrey L

    2018-01-12

    Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast cancer include the lack of highly-specific PR modulators, a poor understanding of the pro- or anti-tumorigenic networks for PR isoforms and ligands, and an incomplete understanding of the cross talk between PR and estrogen receptor (ER) signaling. Through genomic analyses of xenografts treated with various clinically-relevant ER and PR-targeting drugs, we describe how the activation or inhibition of PR differentially reprograms estrogen signaling, resulting in the segregation of transcriptomes into separate PR agonist and antagonist-mediated groups. These findings address an ongoing controversy regarding the clinical utility of PR agonists and antagonists, alone or in combination with tamoxifen, for breast cancer management. Additionally, the two PR isoforms PRA and PRB, bind distinct but overlapping genomic sites and interact with different sets of co-regulators to differentially modulate estrogen signaling to be either pro- or anti-tumorigenic. Of the two isoforms, PRA inhibited gene expression and ER chromatin binding significantly more than PRB. Differential gene expression was observed in PRA and PRB-rich patient tumors and PRA-rich gene signatures had poorer survival outcomes. In support of antiprogestin responsiveness of PRA-rich tumors, gene signatures associated with PR antagonists, but not PR agonists, predicted better survival outcomes. The better patient survival associated with PR antagonists versus PR agonists treatments was further reflected in the higher in vivo anti-tumor activity of therapies that combine tamoxifen with PR antagonists and modulators. This study suggests that distinguishing common effects observed due to concomitant interaction of another receptor with its ligand (agonist or antagonist), from unique isoform and ligand-specific effects will inform the development of biomarkers for patient selection and translation of PR

  5. Progesterone receptor isoforms, agonists and antagonists differentially reprogram estrogen signaling

    Science.gov (United States)

    Singhal, Hari; Greene, Marianne E.; Zarnke, Allison L.; Laine, Muriel; Al Abosy, Rose; Chang, Ya-Fang; Dembo, Anna G.; Schoenfelt, Kelly; Vadhi, Raga; Qiu, Xintao; Rao, Prakash; Santhamma, Bindu; Nair, Hareesh B.; Nickisch, Klaus J.; Long, Henry W.; Becker, Lev; Brown, Myles; Greene, Geoffrey L.

    2018-01-01

    Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast cancer include the lack of highly-specific PR modulators, a poor understanding of the pro- or anti-tumorigenic networks for PR isoforms and ligands, and an incomplete understanding of the cross talk between PR and estrogen receptor (ER) signaling. Through genomic analyses of xenografts treated with various clinically-relevant ER and PR-targeting drugs, we describe how the activation or inhibition of PR differentially reprograms estrogen signaling, resulting in the segregation of transcriptomes into separate PR agonist and antagonist-mediated groups. These findings address an ongoing controversy regarding the clinical utility of PR agonists and antagonists, alone or in combination with tamoxifen, for breast cancer management. Additionally, the two PR isoforms PRA and PRB, bind distinct but overlapping genomic sites and interact with different sets of co-regulators to differentially modulate estrogen signaling to be either pro- or anti-tumorigenic. Of the two isoforms, PRA inhibited gene expression and ER chromatin binding significantly more than PRB. Differential gene expression was observed in PRA and PRB-rich patient tumors and PRA-rich gene signatures had poorer survival outcomes. In support of antiprogestin responsiveness of PRA-rich tumors, gene signatures associated with PR antagonists, but not PR agonists, predicted better survival outcomes. The better patient survival associated with PR antagonists versus PR agonists treatments was further reflected in the higher in vivo anti-tumor activity of therapies that combine tamoxifen with PR antagonists and modulators. This study suggests that distinguishing common effects observed due to concomitant interaction of another receptor with its ligand (agonist or antagonist), from unique isoform and ligand-specific effects will inform the development of biomarkers for patient selection and translation of PR

  6. Effect of Tamoxifen on Seminiferous Tubules Structure during Pregnancy in Adult Mice

    Directory of Open Access Journals (Sweden)

    J Soleimani Rad

    2016-03-01

    Full Text Available Introduction: Tamoxifen is a nonsteroidal drug which mainly treats breast cancer. It is also applied for stimulation of ovulation and remedy of infertility. Regarding the tamoxifen binding to estrogen receptors and the possible role of estrogens in spermatogenesis, the present study aimed to histologically evaluate spermatogenesis in the seminiferous ducts of mice, whose mothers had received tamoxifen during pregnancy. Methods: In the present study, 30 female and 15 male mice of NMRI race were selected for mating. Since 13th day of pregnancy, the experimental group received tamoxifen with the dosage of 5 mg/kg intra-peritoneally for 7 days, wherease the control group received normal saline. After childbirth of the mated mice, male infants were selected and monitored in the standard laboratory conditions. After reaching the age of puberty (6-8Weeks, adult mice were sacrificed by the cervical dislocation, and the testes were removed for histological evaluation of spermatogenesis. After routine histological processing, the samples were studied by the light microscope. Results: Histological studies showed that spermatogenic and Sertoli cells in the seminiferous tubules in control and experimental groups were significantly different, though no difference was observed in the number of Leydig cells in the both groups. Conclusion: The findings of the present study showed that tamoxifen exposure during development can cause histological changes in the seminiferous tubules, which can lead to infertility in the male rat.

  7. Distinct roles for aryl hydrocarbon receptor nuclear translocator and ah receptor in estrogen-mediated signaling in human cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Mark P Labrecque

    Full Text Available The activated AHR/ARNT complex (AHRC regulates the expression of target genes upon exposure to environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD. Importantly, evidence has shown that TCDD represses estrogen receptor (ER target gene activation through the AHRC. Our data indicates that AHR and ARNT act independently from each other at non-dioxin response element sites. Therefore, we sought to determine the specific functions of AHR and ARNT in estrogen-dependent signaling in human MCF7 breast cancer and human ECC-1 endometrial carcinoma cells. Knockdown of AHR with siRNA abrogates dioxin-inducible repression of estrogen-dependent gene transcription. Intriguingly, knockdown of ARNT does not effect TCDD-mediated repression of estrogen-regulated transcription, suggesting that AHR represses ER function independently of ARNT. This theory is supported by the ability of the selective AHR modulator 3',4'-dimethoxy-α-naphthoflavone (DiMNF to repress estrogen-inducible transcription. Furthermore, basal and estrogen-activated transcription of the genes encoding cathepsin-D and pS2 are down-regulated in MCF7 cells but up-regulated in ECC-1 cells in response to loss of ARNT. These responses are mirrored at the protein level with cathepsin-D. Furthermore, knock-down of ARNT led to opposite but corresponding changes in estrogen-stimulated proliferation in both MCF7 and ECC-1 cells. We have obtained experimental evidence demonstrating a dioxin-dependent repressor function for AHR and a dioxin-independent co-activator/co-repressor function for ARNT in estrogen signalling. These results provide us with further insight into the mechanisms of transcription factor crosstalk and putative therapeutic targets in estrogen-positive cancers.

  8. TNF-{alpha} mediates the stimulation of sclerostin expression in an estrogen-deficient condition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Beom-Jun [Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap2-Dong, Seoul (Korea, Republic of); Bae, Sung Jin [Health Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap2-Dong, Seoul (Korea, Republic of); Lee, Sun-Young; Lee, Young-Sun; Baek, Ji-Eun; Park, Sook-Young [Asan Institute for Life Sciences, 388-1 Poongnap2-Dong, Seoul (Korea, Republic of); Lee, Seung Hun [Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap2-Dong, Seoul (Korea, Republic of); Koh, Jung-Min, E-mail: jmkoh@amc.seoul.kr [Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap2-Dong, Seoul (Korea, Republic of); Kim, Ghi Su [Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap2-Dong, Seoul (Korea, Republic of)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer Estrogen deprivation stimulates the bony sclerostin levels with reversal by estrogen. Black-Right-Pointing-Pointer TNF-{alpha} increases the activity and expression of MEF2 in UMR-106 cells. Black-Right-Pointing-Pointer TNF-{alpha} blocker prevents the stimulation of bony sclerostin expression by ovariectomy. Black-Right-Pointing-Pointer No difference in bony sclerostin expression between sham-operated and ovariectomized nude mice. -- Abstract: Although recent clinical studies have suggested a possible role for sclerostin, a secreted Wnt antagonist, in the pathogenesis of postmenopausal osteoporosis, the detailed mechanisms how estrogen deficiency regulates sclerostin expression have not been well-elucidated. Bilateral ovariectomy or a sham operation in female C57BL/6 mice and BALB/c nude mice was performed when they were seven weeks of age. The C57BL/6 mice were intraperitoneally injected with phosphate-buffered serum (PBS), 5 {mu}g/kg {beta}-estradiol five times per week for three weeks, or 10 mg/kg TNF-{alpha} blocker three times per week for three weeks. Bony sclerostin expression was assessed by immunohistochemistry staining in their femurs. The activity and expression of myocyte enhancer factors 2 (MEF2), which is essential for the transcriptional activation of sclerostin, in rat UMR-106 osteosarcoma cells were determined by luciferase reporter assay and western blot analysis, respectively. Bony sclerostin expression was stimulated by estrogen deficiency and it was reversed by estradiol supplementation. When the UMR-106 cells were treated with well-known, estrogen-regulated cytokines, only TNF-{alpha}, but not IL-1 and IL-6, increased the MEF2 activity. Consistently, TNF-{alpha} also increased the nuclear MEF2 expression. Furthermore, the TNF-{alpha} blocker prevented the stimulation of bony sclerostin expression by ovariectomy. We also found that there was no difference in sclerostin expression between ovariectomized

  9. Estrogen mediates innate and adaptive immune alterations to influenza infection in pregnant mice.

    Directory of Open Access Journals (Sweden)

    Michael A Pazos

    Full Text Available Pregnancy is a leading risk factor for severe complications during an influenza virus infection. Women infected during their second and third trimesters are at increased risk for severe cardiopulmonary complications, premature delivery, and death. Here, we establish a murine model of aerosolized influenza infection during pregnancy. We find significantly altered innate antiviral responses in pregnant mice, including decreased levels of IFN-β, IL-1α, and IFN-γ at early time points of infection. We also find reduced cytotoxic T cell activity and delayed viral clearance. We further demonstrate that pregnancy levels of the estrogen 17-β-estradiol are able to induce key anti-inflammatory phenotypes in immune responses to the virus independently of other hormones or pregnancy-related stressors. We conclude that elevated estrogen levels result in an attenuated anti-viral immune response, and that pregnancy-associated morbidities occur in the context of this anti-inflammatory phenotype.

  10. Estrogen mediates innate and adaptive immune alterations to influenza infection in pregnant mice.

    Science.gov (United States)

    Pazos, Michael A; Kraus, Thomas A; Muñoz-Fontela, César; Moran, Thomas M

    2012-01-01

    Pregnancy is a leading risk factor for severe complications during an influenza virus infection. Women infected during their second and third trimesters are at increased risk for severe cardiopulmonary complications, premature delivery, and death. Here, we establish a murine model of aerosolized influenza infection during pregnancy. We find significantly altered innate antiviral responses in pregnant mice, including decreased levels of IFN-β, IL-1α, and IFN-γ at early time points of infection. We also find reduced cytotoxic T cell activity and delayed viral clearance. We further demonstrate that pregnancy levels of the estrogen 17-β-estradiol are able to induce key anti-inflammatory phenotypes in immune responses to the virus independently of other hormones or pregnancy-related stressors. We conclude that elevated estrogen levels result in an attenuated anti-viral immune response, and that pregnancy-associated morbidities occur in the context of this anti-inflammatory phenotype.

  11. 17β-Estradiol inhibits estrogen binding protein-mediated hypha formation in Candida albicans.

    Science.gov (United States)

    Kurakado, Sanae; Kurogane, Rie; Sugita, Takashi

    2017-08-01

    Candida albicans is one of the most prevalent and clinically important fungal pathogens. The ability to change form depending on environmental stress is an important microbial virulence factor. A survey of compounds that inhibit this morphological change identified various steroids, including 17β-estradiol. Interestingly, C. albicans has proteins capable of binding to steroids, including estrogen binding protein (Ebp1). Estrogens regulate cell differentiation and proliferation in humans through estrogen receptor proteins. To determine whether EBP1 regulates a virulence factor, we investigated the effect of 17β-estradiol on the morphological transition of C. albicans using an ebp1 deletion mutant. Treatment with 10 μg/mL of 17β-estradiol inhibited hypha formation, whereas its effect on the ebp1 deletion mutant was decreased compared to that on the wild-type and revertant strains. These data suggest a new pathway for the yeast-to-hypha transition via EBP1 in C. albicans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Coxsackie and adenovirus receptor is a target and a mediator of estrogen action in breast cancer.

    Science.gov (United States)

    Vindrieux, David; Le Corre, Ludovic; Hsieh, Jer-Tsong; Métivier, Raphaël; Escobar, Pauline; Caicedo, Andrès; Brigitte, Madly; Lazennec, Gwendal

    2011-06-01

    The involvement of the coxsackie and adenovirus receptor (CAR), an adhesion molecule known to be the main determinant of adenovirus transduction of the cells, in cancer is currently under investigation. Recent reports suggest that CAR levels are elevated in breast cancer, and this may have an impact on its use as means of delivery for gene therapy. In this study, we show that estradiol (E(2)) treatment of the estrogen receptor (ER)-positive breast cancer cell MCF-7 increases CAR levels and, in turn, enhances adenoviral transduction. Employing the transfection of CAR promoters in breast cancer cells, we show that this regulation of CAR expression occurs at the transcriptional level. In addition, and by chromatin immunoprecipitation, we have identified a crucial region of CAR promoter that controls E(2) responsiveness of CAR gene through the recruitment of ER. Moreover, utilizing CAR antibodies or CAR silencing by RNA interference repressed the estrogen-dependent growth of breast cancer cells, whereas the stable expression of CAR in MCF-7 or MDA-MB-231 cells led to an increased proliferation. Altogether, our data suggest that CAR is a novel estrogen-responsive gene, which is involved in the E(2)-dependent proliferation of breast cancer cells.

  13. Effects of estrogen antagonists on estradiol-enhanced radiation transformation in vitro

    International Nuclear Information System (INIS)

    Umans, R.S.; Kenneddy, A.R.

    1988-01-01

    We have previously reported that radiation and 17β-estrediol can induce transformation in vitro in C3H 10T1/2 cells. In the present series of experiments, we have observed that antagonists of estrogen action, such as c-AMP activating agents(Theophylinne and dibutylc-AMP) and the antiestrogens tamoxifen, suppress radiation/17β-estradiol enhanced transformation in vitro. None of these known estrogen antagonists had a significant effect on transformation induced by radiation alone. Our results with added dibutyl c-AMP, theophylline and tamoxifen suggest that estrogen receptor complex formation may play a role in estrogen-enhanced radiation transformation in vitro (author)

  14. Phenolphthalein metabolite inhibits catechol-O-methyltransferase-mediated metabolism of catechol estrogens: a possible mechanism for carcinogenicity.

    Science.gov (United States)

    Garner, C E; Matthews, H B; Burka, L T

    2000-01-15

    Phenolphthalein (PT), used in over-the-counter laxatives, has recently been identified as a multisite carcinogen in rodents, but the molecular species responsible for the carcinogenicity is not known. A catechol metabolite of PT, hydroxyphenolphthalein (PT-CAT), was recently identified and may be the molecular species responsible for at least part of the toxicity/carcinogenicity of PT. We hypothesize that PT-CAT inhibits the enzyme catechol-O-methyltransferase (COMT) and therefore potentiates genotoxicity by either PT-CAT itself or the endogenous catechol estrogens (CEs) in susceptible tissues. The present studies were conducted to determine the effects of PT treatment and PT-CAT itself on the COMT-mediated metabolism of 4- and 2-hydroxyestradiol both in vitro and in vivo. Female mice were treated with PT (50 mg/kg/d) for 21 days and then euthanized. PT-CAT concentration in urine reached plateau levels by 7 days of exposure. An O-methylated metabolite of PT-CAT was detected in feces. In vitro experiments demonstrated that PT treatment resulted in an increase in free CEs, which are normally cleared by COMT and a concurrent decrease in the capacity of hepatic catechol clearance by COMT. In vitro, PT-CAT was a substrate of COMT, with kinetic properties within the range measured with endogenous substrates. PT-CAT was an extremely potent mixed-type inhibitor of the O-methylation of the catechol estrogens, with 90-300 nM IC50s. The above data, when taken together, suggest that chronic administration of PT may enhance metabolic redox cycling of both PT-CAT and the catechol estrogens and this, in turn, may contribute to PT-induced tumorigenesis.

  15. Müllerian adenosarcoma of the uterus with sarcomatous overgrowth following tamoxifen treatment for breast cancer

    Directory of Open Access Journals (Sweden)

    Carvalho Filomena Marino

    2000-01-01

    Full Text Available Müllerian adenosarcoma with sarcomatous overgrowth presented by a 52-year-old female patient after adjuvant tamoxifen treatment for breast carcinoma is described. The diagnosis was made on histological basis after curettage and complementary total hysterectomy with bilateral salpingo-oophorectomy. The immunohistochemical study showed high expression of estrogen receptors in the epithelial component of the lesion and irregularly positive findings in the stroma. The proliferative activity evaluated by Ki-67 immunoexpression was higher in the stroma than the epithelium. Some of the stromal cells showed rhabdomyoblastic differentiation. The association of tamoxifen use and development of mesenchymal neoplasms is discussed.

  16. Early Endometriosis in Females Is Directed by Immune-Mediated Estrogen Receptor α and IL-6 Cross-Talk.

    Science.gov (United States)

    Burns, Katherine A; Thomas, Seddon Y; Hamilton, Katherine J; Young, Steven L; Cook, Donald N; Korach, Kenneth S

    2018-01-01

    Endometriosis is a gynecological disease that negatively affects the health of 1 in 10 women. Although more information is known about late stage disease, the early initiation of endometriosis and lesion development is poorly understood. Herein, we use a uterine tissue transfer mouse model of endometriosis to examine early disease development and its dependence on estradiol (E2) and estrogen receptor (ER) α within 72 hours of disease initiation. Using wild-type and ERα knockout mice as hosts or donors, we find substantial infiltration of neutrophils and macrophages into the peritoneal cavity. Examining cell infiltration, lesion gene expression, and peritoneal fluid, we find that E2/ERα plays a minor role in early lesion development. Immune-mediated signaling predominates E2-mediated signaling, but 48 hours after the initiation of disease, a blunted interleukin (IL)-6-mediated response is found in developing lesions lacking ERα. Our data provide evidence that the early initiation of endometriosis is predominantly dependent on the immune system, whereas E2/ERα/IL-6-mediated cross-talk plays a partial role. These findings suggest there are two phases of endometriosis-an immune-dependent phase and a hormone-dependent phase, and that targeting the innate immune system could prevent lesion attachment in this susceptible population of women.

  17. SIRT1 Functions as an Important Regulator of Estrogen-Mediated Cardiomyocyte Protection in Angiotensin II-Induced Heart Hypertrophy

    Directory of Open Access Journals (Sweden)

    Tao Shen

    2014-01-01

    Full Text Available Background. Sirtuin 1 (SIRT1 is a member of the sirtuin family, which could activate cell survival machinery and has been shown to be protective in regulation of heart function. Here, we determined the mechanism by which SIRT1 regulates Angiotensin II- (AngII- induced cardiac hypertrophy and injury in vivo and in vitro. Methods. We analyzed SIRT1 expression in the hearts of control and AngII-induced mouse hypertrophy. Female C57BL/6 mice were ovariectomized and pretreated with 17β-estradiol to measure SIRT1 expression. Protein synthesis, cardiomyocyte surface area analysis, qRT-PCR, TUNEL staining, and Western blot were performed on AngII-induced mouse heart hypertrophy samples and cultured neonatal rat ventricular myocytes (NRVMs to investigate the function of SIRT1. Results. SIRT1 expression was slightly upregulated in AngII-induced mouse heart hypertrophy in vivo and in vitro, accompanied by elevated cardiomyocyte apoptosis. SIRT1 overexpression relieves AngII-induced cardiomyocyte hypertrophy and apoptosis. 17β-Estradiol was able to protect cardiomyocytes from AngII-induced injury with a profound upregulation of SIRT1 and activation of AMPK. Moreover, estrogen receptor inhibitor ICI 182,780 and SIRT1 inhibitor niacinamide could block SIRT1’s protective effect. Conclusions. These results indicate that SIRT1 functions as an important regulator of estrogen-mediated cardiomyocyte protection during AngII-induced heart hypertrophy and injury.

  18. Assessment of cellular estrogenic activity based on estrogen receptor-mediated reduction of soluble-form catechol-O-methyltransferase (COMT expression in an ELISA-based system.

    Directory of Open Access Journals (Sweden)

    Philip Wing-Lok Ho

    Full Text Available Xenoestrogens are either natural or synthetic compounds that mimic the effects of endogenous estrogen. These compounds, such as bisphenol-A (BPA, and phthalates, are commonly found in plastic wares. Exposure to these compounds poses major risk to human health because of the potential to cause endocrine disruption. There is huge demand for a wide range of chemicals to be assessed for such potential for the sake of public health. Classical in vivo assays for endocrine disruption are comprehensive but time-consuming and require sacrifice of experimental animals. Simple preliminary in vitro screening assays can reduce the time and expense involved. We previously demonstrated that catechol-O-methyltransferase (COMT is transcriptionally regulated by estrogen via estrogen receptor (ER. Therefore, detecting corresponding changes of COMT expression in estrogen-responsive cells may be a useful method to estimate estrogenic effects of various compounds. We developed a novel cell-based ELISA to evaluate cellular response to estrogenicity by reduction of soluble-COMT expression in ER-positive MCF-7 cells exposed to estrogenic compounds. In contrast to various existing methods that only detect bioactivity, this method elucidates direct physiological effect in a living cell in response to a compound. We validated our assay using three well-characterized estrogenic plasticizers - BPA, benzyl butyl phthalate (BBP, and di-n-butyl phthalate (DBP. Cells were exposed to either these plasticizers or 17β-estradiol (E2 in estrogen-depleted medium with or without an ER-antagonist, ICI 182,780, and COMT expression assayed. Exposure to each of these plasticizers (10(-9-10(-7M dose-dependently reduced COMT expression (p<0.05, which was blocked by ICI 182,780. Reduction of COMT expression was readily detectable in cells exposed to picomolar level of E2, comparable to other in vitro assays of similar sensitivity. To satisfy the demand for in vitro assays targeting different

  19. Estrogen induces apoptosis in estrogen deprivation-resistant breast cancer through stress responses as identified by global gene expression across time.

    Science.gov (United States)

    Ariazi, Eric A; Cunliffe, Heather E; Lewis-Wambi, Joan S; Slifker, Michael J; Willis, Amanda L; Ramos, Pilar; Tapia, Coya; Kim, Helen R; Yerrum, Smitha; Sharma, Catherine G N; Nicolas, Emmanuelle; Balagurunathan, Yoganand; Ross, Eric A; Jordan, V Craig

    2011-11-22

    In laboratory studies, acquired resistance to long-term antihormonal therapy in breast cancer evolves through two phases over 5 y. Phase I develops within 1 y, and tumor growth occurs with either 17β-estradiol (E(2)) or tamoxifen. Phase II resistance develops after 5 y of therapy, and tamoxifen still stimulates growth; however, E(2) paradoxically induces apoptosis. This finding is the basis for the clinical use of estrogen to treat advanced antihormone-resistant breast cancer. We interrogated E(2)-induced apoptosis by analysis of gene expression across time (2-96 h) in MCF-7 cell variants that were estrogen-dependent (WS8) or resistant to estrogen deprivation and refractory (2A) or sensitive (5C) to E(2)-induced apoptosis. We developed a method termed differential area under the curve analysis that identified genes uniquely regulated by E(2) in 5C cells compared with both WS8 and 2A cells and hence, were associated with E(2)-induced apoptosis. Estrogen signaling, endoplasmic reticulum stress (ERS), and inflammatory response genes were overrepresented among the 5C-specific genes. The identified ERS genes indicated that E(2) inhibited protein folding, translation, and fatty acid synthesis. Meanwhile, the ERS-associated apoptotic genes Bcl-2 interacting mediator of cell death (BIM; BCL2L11) and caspase-4 (CASP4), among others, were induced. Evaluation of a caspase peptide inhibitor panel showed that the CASP4 inhibitor z-LEVD-fmk was the most active at blocking E(2)-induced apoptosis. Furthermore, z-LEVD-fmk completely prevented poly (ADP-ribose) polymerase (PARP) cleavage, E(2)-inhibited growth, and apoptotic morphology. The up-regulated proinflammatory genes included IL, IFN, and arachidonic acid-related genes. Functional testing showed that arachidonic acid and E(2) interacted to superadditively induce apoptosis. Therefore, these data indicate that E(2) induced apoptosis through ERS and inflammatory responses in advanced antihormone-resistant breast cancer.

  20. Aryl hydrocarbon receptor-mediated and estrogenic activities of oxygenated polycyclic aromatic hydrocarbons and azaarenes originally identified in extracts of river sediments

    Czech Academy of Sciences Publication Activity Database

    Machala, M.; Ciganek, M.; Bláha, L.; Minksová, Kateřina; Vondráček, Jan

    2001-01-01

    Roč. 20, č. 12 (2001), s. 2736-2743 ISSN 0730-7268 R&D Projects: GA ČR GA525/98/1266 Institutional research plan: CEZ:AV0Z5004920 Keywords : aryl hydrocarbon-mediated activity * estrogenicity * reporter gene bioassays Subject RIV: BO - Biophysics Impact factor: 1.964, year: 2001

  1. Quantitative proteomics and transcriptomics addressing the estrogen receptor subtype-mediated effects in T47D breast cancer cells exposed to the phytoestrogen genistein

    NARCIS (Netherlands)

    Sotoca Covaleda, A.M.; Sollewijn Gelpke, M.D.; Boeren, S.; Ström, A.; Gustafsson, J.A.; Murk, A.J.; Rietjens, I.M.C.M.; Vervoort, J.J.M.

    2011-01-01

    The present study addresses, by transcriptomics and quantitative SILAC-based proteomics, the estrogen receptor alpha (ER) and beta (ERß)-mediated effects on gene and protein expression in T47D breast cancer cells exposed to the phytoestrogen genistein. Using the T47D human breast cancer cell line

  2. A randomized trial of exemestane after two to three years of tamoxifen therapy in postmenopausal women with primary breast cancer.

    Science.gov (United States)

    Coombes, R Charles; Hall, Emma; Gibson, Lorna J; Paridaens, Robert; Jassem, Jacek; Delozier, Thierry; Jones, Stephen E; Alvarez, Isabel; Bertelli, Gianfilippo; Ortmann, Olaf; Coates, Alan S; Bajetta, Emilio; Dodwell, David; Coleman, Robert E; Fallowfield, Lesley J; Mickiewicz, Elizabeth; Andersen, Jorn; Lønning, Per E; Cocconi, Giorgio; Stewart, Alan; Stuart, Nick; Snowdon, Claire F; Carpentieri, Marina; Massimini, Giorgio; Bliss, Judith M; van de Velde, Cornelius

    2004-03-11

    Tamoxifen, taken for five years, is the standard adjuvant treatment for postmenopausal women with primary, estrogen-receptor-positive breast cancer. Despite this treatment, however, some patients have a relapse. We conducted a double-blind, randomized trial to test whether, after two to three years of tamoxifen therapy, switching to exemestane was more effective than continuing tamoxifen therapy for the remainder of the five years of treatment. The primary end point was disease-free survival. Of the 4742 patients enrolled, 2362 were randomly assigned to switch to exemestane, and 2380 to continue to receive tamoxifen. After a median follow-up of 30.6 months, 449 first events (local or metastatic recurrence, contralateral breast cancer, or death) were reported--183 in the exemestane group and 266 in the tamoxifen group. The unadjusted hazard ratio in the exemestane group as compared with the tamoxifen group was 0.68 (95 percent confidence interval, 0.56 to 0.82; P<0.001 by the log-rank test), representing a 32 percent reduction in risk and corresponding to an absolute benefit in terms of disease-free survival of 4.7 percent (95 percent confidence interval, 2.6 to 6.8) at three years after randomization. Overall survival was not significantly different in the two groups, with 93 deaths occurring in the exemestane group and 106 in the tamoxifen group. Severe toxic effects of exemestane were rare. Contralateral breast cancer occurred in 20 patients in the tamoxifen group and 9 in the exemestane group (P=0.04). Exemestane therapy after two to three years of tamoxifen therapy significantly improved disease-free survival as compared with the standard five years of tamoxifen treatment. Copyright 2004 Massachusetts Medical Society

  3. Estrogen receptor mediated effects of Cimicifuga extracts on human breast cancer cells.

    Science.gov (United States)

    Park, Joonwoo; Shim, Myeongkuk; Rhyu, Mee-Ra; Lee, YoungJoo

    2012-11-01

    Cimicifuga racemosa extracts have long been used to treat female reproductive disorders both in Asia and Europe. Here in this study, we examined the possible estrogen receptor (ER)alpha effects of Cimicifuga heracleifolia var. bifida ethanol extract (C-Ex), which has been used traditionally in Asia, in MCF-7 cells. The activity of C-Ex was characterized in a transient transfection system, using ERa and estrogen-responsive luciferase plasmids in HEK 293 cells and endogenous target genes were studied in MCF-7 cells. C-Ex failed to activate ERalpha and at a concentration of 0.005-0.5 mg/ml as examined by reporter activity. In addition, no statistically significant antiestrogenic activity was observed. However, to our interest, C-Ex enhanced expression of VEGF at 0.5 mg/ml concentration and repressed ERalpha both at the mRNA and protein levels in MCF-7 cells. These results suggested that C-Ex does not activate or inactivate ERalpha in a direct manner, but the extracts may affect factors in ER signal transduction pathway.

  4. Assessment of Estrogenic Endocrine-Disrupting Chemical Actions in the Brain Using in Vivo Somatic Gene Transfer

    Science.gov (United States)

    Trudeau, Vance L.; Turque, Nathalie; Le Mével, Sébastien; Alliot, Caroline; Gallant, Natacha; Coen, Laurent; Pakdel, Farzad; Demeneix, Barbara

    2005-01-01

    Estrogenic endocrine-disrupting chemicals abnormally stimulate vitellogenin gene expression and production in the liver of many male aquatic vertebrates. However, very few studies demonstrate the effects of estrogenic pollutants on brain function. We have used polyethylenimine-mediated in vivo somatic gene transfer to introduce an estrogen response element–thymidine kinase–luciferase (ERE-TK-LUC) construct into the brain. To determine if waterborne estrogenic chemicals modulate gene transcription in the brain, we injected the estrogen-sensitive construct into the brains of Nieuwkoop-Faber stage 54 Xenopus laevis tadpoles. Both ethinylestradiol (EE2; p 0.05). The mixed antagonist/agonist tamoxifen was estrogenic in vivo and increased (p < 0.003) luciferase activity in the tadpole brain by 2.3-fold. There have been no previous reports of somatic gene transfer to the fish brain; therefore, it was necessary to optimize injection and transfection conditions for the adult goldfish (Carassius auratus). Following third brain ventricle injection of cytomegalovirus (CMV)-green fluorescent protein or CMV-LUC gene constructs, we established that cells in the telencephalon and optic tectum are transfected. Optimal transfections were achieved with 1 μg DNA complexed with 18 nmol 22 kDa polyethylenimine 4 days after brain injections. Exposure to EE2 increased brain luciferase activity by 2-fold in males (p < 0.05) but not in females. Activation of an ERE-dependent luciferase reporter gene in both tadpole and fish indicates that waterborne estrogens can directly modulate transcription of estrogen-responsive genes in the brain. We provide a method adaptable to aquatic organisms to study the direct regulation of estrogen-responsive genes in vivo. PMID:15743723

  5. Reconsidering the roles of endogenous estrogens and xenoestrogens: the membrane estradiol receptor G protein-coupled receptor 30 (GPR30) mediates the effects of various estrogens.

    Science.gov (United States)

    Kadokawa, Hiroya; Pandey, Kiran; Onalenna, Kereilwe; Nahar, Asrafun

    2018-03-06

    Estrone (E1) and estriol (E3) are considered "weak" estrogens, which exert suppressive effects through estrogen receptors α and β. However, recent studies have demonstrated that E1 and E3, as well as estradiol (E2), suppress gonadotropin-releasing hormone-induced luteinizing hormone secretion from bovine gonadotrophs via G-protein-coupled receptor 30, which is expressed in various reproductive organs. Currently, there is a lack of fundamental knowledge regarding E1 and E3, including their blood levels. In addition, xenoestrogens may remain in the body over long time periods because of enterohepatic circulation. Therefore, it is time to reconsider the roles of endogenous estrogens and xenoestrogens for reproduction.

  6. Tamoxifen affects glucose and lipid metabolism parameters, causes browning of subcutaneous adipose tissue and transient body composition changes in C57BL/6NTac mice

    International Nuclear Information System (INIS)

    Hesselbarth, Nico; Pettinelli, Chiara; Gericke, Martin; Berger, Claudia; Kunath, Anne; Stumvoll, Michael; Blüher, Matthias; Klöting, Nora

    2015-01-01

    Tamoxifen is a selective estrogen receptor (ER) modulator which is widely used to generate inducible conditional transgenic mouse models. Activation of ER signaling plays an important role in the regulation of adipose tissue (AT) metabolism. We therefore tested the hypothesis that tamoxifen administration causes changes in AT biology in vivo. 12 weeks old male C57BL/6NTac mice were treated with either tamoxifen (n = 18) or vehicle (n = 18) for 5 consecutive days. Tamoxifen treatment effects on body composition, energy homeostasis, parameters of AT biology, glucose and lipid metabolism were investigated up to an age of 18 weeks. We found that tamoxifen treatment causes: I) significantly increased HbA 1c , triglyceride and free fatty acid serum concentrations (p < 0.01), II) browning of subcutaneous AT and increased UCP-1 expression, III) increased AT proliferation marker Ki67 mRNA expression, IV) changes in adipocyte size distribution, and V) transient body composition changes. Tamoxifen may induce changes in body composition, whole body glucose and lipid metabolism and has significant effects on AT biology, which need to be considered when using Tamoxifen as a tool to induce conditional transgenic mouse models. Our data further suggest that tamoxifen-treated wildtype mice should be characterized in parallel to experimental transgenic models to control for tamoxifen administration effects. - Highlights: • Tamoxifen treatment causes significantly increased HbA 1c , triglyceride and free fatty acid serum concentrations. • Tamoxifen induces browning of subcutaneous AT and increased UCP-1 expression. • Tamoxifen changes adipocyte size distribution, and transient body composition

  7. Tamoxifen affects glucose and lipid metabolism parameters, causes browning of subcutaneous adipose tissue and transient body composition changes in C57BL/6NTac mice

    Energy Technology Data Exchange (ETDEWEB)

    Hesselbarth, Nico; Pettinelli, Chiara [Department of Medicine, University of Leipzig, D-04103 Leipzig (Germany); Gericke, Martin [Institute of Anatomy, University of Leipzig, D-04103 Leipzig (Germany); Berger, Claudia [IFB Adiposity Disease, Core Unit Animal Models, University of Leipzig, D-04103 Leipzig (Germany); Kunath, Anne [German Center for Diabetes Research (DZD), Leipzig (Germany); Stumvoll, Michael; Blüher, Matthias [Department of Medicine, University of Leipzig, D-04103 Leipzig (Germany); Klöting, Nora, E-mail: nora.kloeting@medizin.uni-leipzig.de [IFB Adiposity Disease, Core Unit Animal Models, University of Leipzig, D-04103 Leipzig (Germany)

    2015-08-28

    Tamoxifen is a selective estrogen receptor (ER) modulator which is widely used to generate inducible conditional transgenic mouse models. Activation of ER signaling plays an important role in the regulation of adipose tissue (AT) metabolism. We therefore tested the hypothesis that tamoxifen administration causes changes in AT biology in vivo. 12 weeks old male C57BL/6NTac mice were treated with either tamoxifen (n = 18) or vehicle (n = 18) for 5 consecutive days. Tamoxifen treatment effects on body composition, energy homeostasis, parameters of AT biology, glucose and lipid metabolism were investigated up to an age of 18 weeks. We found that tamoxifen treatment causes: I) significantly increased HbA{sub 1c}, triglyceride and free fatty acid serum concentrations (p < 0.01), II) browning of subcutaneous AT and increased UCP-1 expression, III) increased AT proliferation marker Ki67 mRNA expression, IV) changes in adipocyte size distribution, and V) transient body composition changes. Tamoxifen may induce changes in body composition, whole body glucose and lipid metabolism and has significant effects on AT biology, which need to be considered when using Tamoxifen as a tool to induce conditional transgenic mouse models. Our data further suggest that tamoxifen-treated wildtype mice should be characterized in parallel to experimental transgenic models to control for tamoxifen administration effects. - Highlights: • Tamoxifen treatment causes significantly increased HbA{sub 1c}, triglyceride and free fatty acid serum concentrations. • Tamoxifen induces browning of subcutaneous AT and increased UCP-1 expression. • Tamoxifen changes adipocyte size distribution, and transient body composition.

  8. Quantitative mapping of RNA-mediated nuclear estrogen receptor β interactome in human breast cancer cells

    Science.gov (United States)

    Giurato, Giorgio; Nassa, Giovanni; Salvati, Annamaria; Alexandrova, Elena; Rizzo, Francesca; Nyman, Tuula A.; Weisz, Alessandro; Tarallo, Roberta

    2018-03-01

    The nuclear receptor estrogen receptor 2 (ESR2, ERβ) modulates cancer cell proliferation and tumor growth, exerting an oncosuppressive role in breast cancer (BC). Interaction proteomics by tandem affinity purification coupled to mass spectrometry was previously applied in BC cells to identify proteins acting in concert with ERβ to control key cellular functions, including gene transcription, RNA splicing and post-transcriptional mRNA regulation. These studies revealed an involvement of RNA in ERβ interactome assembly and functions. By applying native protein complex purification followed by nano LC-MS/MS before and after in vitro RNA removal, we generated a large dataset of newly identified nuclear ERβ interactors, including a subset associating with the receptor via RNA bridging. These datasets will be useful to investigate further the role of ERβ, nuclear RNAs and the other proteins identified here in BC and other cell types.

  9. APOBEC3B-Mediated Cytidine Deamination Is Required for Estrogen Receptor Action in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Manikandan Periyasamy

    2015-10-01

    Full Text Available Estrogen receptor α (ERα is the key transcriptional driver in a large proportion of breast cancers. We report that APOBEC3B (A3B is required for regulation of gene expression by ER and acts by causing C-to-U deamination at ER binding regions. We show that these C-to-U changes lead to the generation of DNA strand breaks through activation of base excision repair (BER and to repair by non-homologous end-joining (NHEJ pathways. We provide evidence that transient cytidine deamination by A3B aids chromatin modification and remodelling at the regulatory regions of ER target genes that promotes their expression. A3B expression is associated with poor patient survival in ER+ breast cancer, reinforcing the physiological significance of A3B for ER action.

  10. Novel Carbonyl Analogues of Tamoxifen: Design, Synthesis, and Biological Evaluation

    Science.gov (United States)

    Kasiotis, Konstantinos M.; Lambrinidis, George; Fokialakis, Nikolas; Tzanetou, Evangelia N.; Mikros, Emmanuel; Haroutounian, Serkos A.

    2017-09-01

    Aim of this work was to provide tamoxifen analogues with enhanced estrogen receptor binding affinity. Hence, several derivatives were prepared using an efficient triarylethylenes synthetic protocol. The novel compounds bioactivity was evaluated through the determination of their receptor binding affinity and their agonist/antagonist activity against breast cancer tissue using a MCF-7 cell-based assay. Phenyl esters 6a,b and 8a,b exhibited binding affinity to both ERα and ERβ higher than 4-hydroxytamoxifen while compounds 13 and 14 have shown cellular antiestrogenic activity similar to 4-hydroxytamoxifen and the known estrogen receptor inhibitor ICI182,780. Theoretical calculations and molecular modelling were applied to investigate, support and explain the biological profile of the new compounds. The relevant data indicated an agreement between calculations and demonstrated biological activity allowing to extract useful structure-activity relationships. Results herein underline that modifications of tamoxifen structure still provide molecules with substantial activity, as portrayed in the inhibition of MCF-7 cells proliferation.

  11. Comparative Cistromics Reveals Genomic Cross-talk between FOXA1 and ER alpha in Tamoxifen-Associated Endometrial Carcinomas

    NARCIS (Netherlands)

    Droog, Marjolein; Nevedomskaya, Ekaterina; Kim, Yongsoo; Severson, Tesa; Flach, Koen D.; Opdam, Mark; Schuurman, Karianne; Gradowska, Patrycja; Hauptmann, Michael; Dackus, Gwen; Hollema, Harry; Mourits, Marian; Nederlof, Petra; van Boven, Hester; Linn, Sabine C.; Wessels, Lodewyk; van Leeuwen, Flora E.; Zwart, Wilbert

    2016-01-01

    Tamoxifen, a small-molecule antagonist of the transcription factor estrogen receptor alpha (ER alpha) used to treat breast cancer, increases risks of endometrial cancer. However, no parallels of ER alpha transcriptional action in breast and endometrial tumors have been found that might explain this

  12. The effect of tamoxifen on pubertal bone development in adolescents with pubertal gynecomastia.

    Science.gov (United States)

    Akgül, Sinem; Derman, Orhan; Kanbur, Nuray

    2016-01-01

    During puberty, estrogen has a biphasic effect on epiphyses; at low levels, it leads to an increase in height and bone mass, whereas at high levels, it leads to closure of the epiphysis. Tamoxifen is a selective estrogen receptor modulator that has been used in the treatment of pubertal gynecomastia. Although it has not been approved for this indication, studies have shown it to be both successful and safe. In males, the peak of pubertal bone development occurs during Tanner stage 3-4, which is also when pubertal gynecomastia reaches its highest prevalence. Thus tamoxifen treatment could potentially effect pubertal bone development. The aim of this study was to assess the effects of tamoxifen on bone mineral density (BMD) and skeletal maturation when used for pubertal gynecomastia. We evaluated 20 boys with pubertal gynecomastia receiving tamoxifen for at least 4 months. BMD was measured with dual-energy X-ray absorptiometry. Z-score and absolute BMD (g/cm(2)) was determined at baseline and 2 months after completing tamoxifen treatment. Bone age and height was evaluated before treatment and again one year later. Using absolute BMD (g/cm(2)), the mean difference from baseline was significant between the two groups both at spine (p=0.002) and femur (p=0.001), but not with the Z-score. This result was attributed to the expected increase during puberty according to sex and age. No significant effect on skeletal maturation was found (p=1.112). We conclude that when pubertal bone development is concerned, tamoxifen is safe for the treatment of pubertal gynecomastia as neither bone mineralization nor growth potential was affected.

  13. Tamoxifen induces resistance to activated protein C.

    Science.gov (United States)

    Rühl, Heiko; Schröder, Lars; Müller, Jens; Fimmers, Rolf; Sukhitashvili, Shorena; Welz, Julia; Kuhn, Walther C; Oldenburg, Johannes; Rudlowski, Christian; Pötzsch, Bernd

    2014-05-01

    The estrogen antagonist tamoxifen (TAM) increases the thrombotic risk similar to estrogen containing oral contraceptives (OC). In OC users this risk is attributed to alterations of hemostasis resulting in acquired resistance to activated protein C (APC). TAM-induced APC resistance has not been reported yet. Blood samples were collected prospectively from women with breast cancer before (n=25) and monthly after start of adjuvant TAM treatment (n=75). APC resistance was evaluated on basis of the effect of APC on the endogenous thrombin generation potential. To detect increased in vivo APC generation APC plasma levels were measured using a highly sensitive oligonucleotide-based enzyme capture assay. Routine hemostasis parameters were measured additionally. APC sensitivity decreased by 41% (p=0.001) compared to baseline after one month of TAM application and remained significantly decreased during the study period. Free protein S increased (p=0.008) while other analyzed procoagulant factors, inhibitors, and activation markers of coagulation decreased or did not change significantly. In five patients the APC concentration increased to non-physiological levels but an overall significant increase of APC was not observed. This is the first study showing acquired APC resistance under TAM therapy. Acquired APC resistance might explain the increased thrombotic risk during TAM treatment. Observed changes of hemostasis parameters suggest different determinants of TAM-induced APC resistance than in OC-induced APC resistance. The presence of acquired APC resistance in TAM patients warrants further evaluation if these patients may benefit from antithrombotic prophylaxis in the presence of additional thrombotic risk factors. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Clinical evidence on the magnitude of change in growth pathway activity in relation to Tamoxifen resistance is required.

    Science.gov (United States)

    Mansouri, Sepideh; Farahmand, Leila; Teymourzadeh, Azin; Majidzadeh-A, Keivan

    2017-08-08

    Despite prolonged disease-free survival and overall survival rates in estrogen receptor (ER)-positive patients undergoing adjuvant treatment, Tamoxifen therapy tends to fail due to eventual acquisition of resistance. Although numerous studies have emphasized the role of receptor tyrosine kinases (RTKs) in the development of Tamoxifen resistance, inadequate clinical evidence is available regarding the alteration of biomarker expression during acquired resistance, thus undermining the validity of the findings. Results of two meta-analyses investigating the effect of HER2 status on the prognosis of Tamoxifen-receiving patients have demonstrated that despite HER2-negative patients having longer disease-free survival; there is no difference in overhaul survival between the two groups. Furthermore, due to the intricate molecular interactions among estrogen receptors including ERα36, ERα66, and also RTKs, it is not surprising that RTK suppression does not restore Tamoxifen sensitivity. In considering such a complex network, we speculate that by the time HER2/EGFR is suppressed via targeted therapies, activation of ERα66 and ERα36 initiate molecular signaling pathways downstream of RTKs, thereby enhancing cell proliferation even in the presence of both Tamoxifen and RTK inhibitors. Although clinical findings regarding the molecular pathways downstream of RTKs have been thoroughly discussed in this review, further clinical studies are required in determining a consistency between preclinical and clinical findings. Discovering the best targets in preventing tumor progression requires thorough comprehension of estrogen-dependent and estrogen-independent pathways during Tamoxifen resistance development. Indeed, exploring additional clinically-proven targets would allow for better characterized treatments being available for breast cancer patients. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. Combinational treatment of gap junctional activator and tamoxifen in breast cancer cells.

    Science.gov (United States)

    Gakhar, Gunjan; Hua, Duy H; Nguyen, Thu Annelise

    2010-01-01

    fragmentation. Tamoxifen alone and in combination with PQ1 showed a decrease in the expression of survivin, whereas PQ1 alone was shown to be independent of the survivin-mediated pathway. This suggests that an increase in gap junction activity can potentiate the effect of tamoxifen. The combinational treatment of tamoxifen and PQ1 also showed a significant decrease in cell viability compared with tamoxifen treatment alone. The gap junction inhibitor carbenexolone was shown to increase cell proliferation by increased cyclin D1 expression, MTT assay, and Ki67 expression. It further decreased cell death. This study shows for the first time that combinational treatment of tamoxifen and PQ1 (a gap junctional activator) can be used to potentiate apoptosis of T47D human breast cancer cells. Thus, a gap junctional activator, PQ1, could potentially alter either the length or dose of tamoxifen clinically used for breast cancer patients.

  16. Functional characterization of estrogen receptor subtypes, ERα and ERβ, mediating vitellogenin production in the liver of rainbow trout

    International Nuclear Information System (INIS)

    Leanos-Castaneda, Olga; Kraak, Glen van der

    2007-01-01

    The estrogen-dependent process of vitellogenesis is a key function on oviparous fish reproduction and it has been widely used as an indicator of xenoestrogen exposure. The two estrogen receptor (ER) subtypes, ERα and ERβ, are often co-expressed in the liver of fish. The relative contribution of each ER subtype to modulate vitellogenin production by hepatocytes was studied using selected compounds known to preferentially interact with specific ER subtypes: propyl-pyrazole-triol (PPT) an ERα selective agonist, methyl-piperidino-pyrazole (MPP) an ERα selective antagonist, and diarylpropionitrile (DPN) an ERβ selective agonist. First, the relative binding affinity of the test compounds to estradiol for rainbow trout hepatic nuclear ER was determined using a competitive ligand binding assay. All the test ligands achieved complete displacement of specific [ 3 H]-estradiol binding from the nuclear ER extract. This indicates that the test ligands have the potential to modify the ER function in the rainbow trout liver. Secondly, the ability of the test compounds to induce or inhibit vitellogenin production by primary cultures of rainbow trout hepatocytes was studied. Estradiol and DPN were the only compounds that induced a dose-dependent increase on vitellogenin synthesis. The lack of vitellogenin induction by PPT indicates that ERα could not have a role on this reproductive process whereas the ability of DPN to induce vitellogenin production supports the participation of ERβ. In addition, this hypothesis is reinforced by the results obtained from MPP plus estradiol. On one hand, the absence of suppressive activity of MPP in the estradiol-induced vitellogenin production does not support the participation of ERα. On the other hand, once blocked ERα with MPP, the only manifestation of agonist activity of estradiol would be achieved via ERβ. In conclusion, the present results indicate that vitellogenin production is mainly mediated through ERβ, implying, furthermore

  17. Superinduction of estrogen receptor mediated gene expression in luciferase based reporter gene assays is mediated by a post-transcriptional mechanism

    NARCIS (Netherlands)

    Sotoca Covaleda, A.M.; Bovee, T.F.H.; Brand, W.; Velikova, N.R.; Murk, A.J.; Vervoort, J.J.M.; Rietjens, I.M.C.M.

    2010-01-01

    Several estrogenic compounds including the isoflavonoid genistein have been reported to induce a higher maximal response than the natural estrogen 17ß-estradiol in in vitro luciferase based reporter gene bioassays for testing estrogenicity. The phenomenon has been referred to as superinduction. The

  18. Potential Therapeutic Benefit of Combining Gefitinib and Tamoxifen for Treating Advanced Lung Adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Chien-Ming Liu

    2015-01-01

    Full Text Available Introduction. Epidermal growth factor receptor (EGFR mutations are known as oncogene driver mutations and with EGFR mutations exhibit good response to the EGFR tyrosine kinase inhibitor Gefitinib. Some studies have shown that activation of estrogen and estrogen receptor α or β (ERα/β promote adenocarcinoma. We evaluated the relationship between the two receptors and the potential therapeutic benefit with Gefitinib and Tamoxifen. Methods. We assessed the association between EGFR mutations as well as ERα/β expression/location and overall survival in a cohort of 55 patients with LAC from a single hospital. PC9 (EGFR exon 19 deletion mutant; Gefitinib-vulnerable cells and A549 (EGFR wild type; Gefitinib-resistant cells cancer cells were used to evaluate the in vitro therapeutic benefits of combining Gefitinib and Tamoxifen. Results. We found that the cytosolic but not the nuclear expression of ERβ was associated with better OS in LAC tumors but not associated with EGFR mutation. The in vitro study showed that combined Gefitinib and Tamoxifen resulted in increased apoptosis and cytosolic expression of ERβ. In addition, combining both medications resulted in reduced cell growth and increased the cytotoxic effect of Gefitinib. Conclusion. Tamoxifen enhanced advanced LAC cytotoxic effect induced by Gefitinib by arresting ERβ in cytosol.

  19. MEK activity controls IL-8 expression in tamoxifen-resistant MCF-7 breast cancer cells.

    Science.gov (United States)

    Kim, Sangmin; Jeon, Myeongjin; Lee, Jeong Eon; Nam, Seok Jin

    2016-04-01

    Although tamoxifen reduces disease progression, tamoxifen resistance occurs during the course of estrogen receptor-positive [ER+] breast cancer treatment. In the present study, we investigated the possibility that interleukin-8 (IL-8) is a prognostic marker for tamoxifen resistance and aimed to clarify the regulation of IL-8 expression in tamoxifen-resistant cells. Clinically, IL-8 expression is positively correlated with survival in luminal A type breast cancer patients, but not in luminal B type breast cancer patients. In addition, the levels of IL-8 mRNA and protein expression were significantly increased in tamoxifen-resistant (TamR) cells compared to tamoxifen-sensitive (TamS) cells. To determine the regulatory mechanism of IL-8 expression in TamR cells, we analyzed the activities of signaling molecules. Our results showed that the phosphorylation levels of MEK and Akt were markedly increased in TamR cells, but there was no change in the phosphorylation level of p38 MAPK. On the contrary, we observed that elevated IL-8 mRNA expression was suppressed by a specific MEK1/2 inhibitor, UO126, but not by the specific PI-3K inhibitor LY294002, in TamR cells, whereas, we found that overexpression of constitutively active-MEK (CA-MEK) significantly increased the levels of IL-8 mRNA expression in TamS cells. Finally, we investigated the effect of the specific CXCR1/2 inhibitor SB225002 on anchorage-independent growth of TamR cells, and found that the growth was completely suppressed by SB225002. Taken together, our results demonstrate that IL-8 expression is regulated through a MEK/ERK-dependent pathway in TamR cells, suggesting that IL-8 and its receptors may be promising therapeutic targets for overcoming tamoxifen resistance.

  20. Tamoxifen up-regulates catalase production, inhibits vessel wall neutrophil infiltration, and attenuates development of experimental abdominal aortic aneurysms.

    Science.gov (United States)

    Grigoryants, Vladimir; Hannawa, Kevin K; Pearce, Charles G; Sinha, Indranil; Roelofs, Karen J; Ailawadi, Gorav; Deatrick, Kristopher B; Woodrum, Derek T; Cho, Brenda S; Henke, Peter K; Stanley, James C; Eagleton, Matthew J; Upchurch, Gilbert R

    2005-01-01

    Selective estrogen receptor modulators (SERMs), similar to estrogens, possess vasoprotective effects by reducing release of reactive oxygen species. Little is known about the potential effects of SERMs on the pathogenesis of abdominal aortic aneurysms (AAAs). This study's objective was to investigate the growth of experimental AAAs in the setting of the SERM tamoxifen. In the first set of experiments, adult male rats underwent subcutaneous tamoxifen pellet (delivering 10 mg/kg/day) implantation (n = 14) or sham operation (n = 16). Seven days later, all animals underwent pancreatic elastase perfusion of the abdominal aorta. Aortic diameters were determined at that time, and aortas were harvested 7 and 14 days after elastase perfusion for immunohistochemistry, real-time polymerase chain reaction, Western blot analysis, and zymography. In the second set of experiments, a direct irreversible catalase inhibitor, 3-amino-1,2,4-triazole (AT), was administered intraperitoneally (1 mg/kg) daily to tamoxifen-treated (n = 6) and control rats (n = 6), starting on day 7 after elastase perfusion. Aortic diameters were measured on day 14. In a third set of experiments, rats were perfused with catalase (150 mg/kg) after the elastase (n = 5), followed by daily intravenous injections of catalase (150 mg/kg/day) administered for 10 days. A control group of rats (n = 7) received 0.9% NaCl instead of catalase. Mean AAA diameters were approximately 50% smaller in tamoxifen-treated rats compared with sham rats 14 days after elastase perfusion (P = .002). The tamoxifen-treated group's aortas had a five-fold increase in catalase mRNA expression (P = .02) on day 7 and an eight-fold increase in catalase protein on day 14 (P = .04). Matrix metalloprotroteinase-9 activity was 2.4-fold higher (P = .01) on day 7 in the aortas of the controls compared to the tamoxifen-treated group's aortas. Tamoxifen-treated rats had approximately 40% fewer aortic polymorphonuclear neutrophils compared to

  1. Estradiol affects liver mitochondrial function in ovariectomized and tamoxifen-treated ovariectomized female rats

    International Nuclear Information System (INIS)

    Moreira, Paula I.; Custodio, Jose B.A.; Nunes, Elsa; Moreno, Antonio; Seica, Raquel; Oliveira, Catarina R.; Santos, Maria S.

    2007-01-01

    Given the tremendous importance of mitochondria to basic cellular functions as well as the critical role of mitochondrial impairment in a vast number of disorders, a compelling question is whether 17β-estradiol (E2) modulates mitochondrial function. To answer this question we exposed isolated liver mitochondria to E2. Three groups of rat females were used: control, ovariectomized and ovariectomized treated with tamoxifen. Tamoxifen has antiestrogenic effects in the breast tissue and is the standard endocrine treatment for women with breast cancer. However, under certain circumstances and in certain tissues, tamoxifen can also exert estrogenic agonist properties. We observed that at basal conditions, ovariectomy and tamoxifen treatment do not induce any statistical alteration in oxidative phosphorylation system and respiratory chain parameters. Furthermore, tamoxifen treatment increases the capacity of mitochondria to accumulate Ca 2+ delaying the opening of the permeability transition pore. The presence of 25 μM E2 impairs respiration and oxidative phosphorylation system these effects being similar in all groups of animals studied. Curiously, E2 protects against lipid peroxidation and increases the production of H 2 O 2 in energized mitochondria of control females. Our results indicate that E2 has in general deleterious effects that lead to mitochondrial impairment. Since mitochondrial dysfunction is a triggering event of cell degeneration and death, the use of exogenous E2 must be carefully considered

  2. Tamoxifen: an FDA approved drug with neuroprotective effects for spinal cord injury recovery

    Directory of Open Access Journals (Sweden)

    Jennifer M Colón

    2016-01-01

    Full Text Available Spinal cord injury (SCI is a condition without a cure, affecting sensory and/or motor functions. The physical trauma to the spinal cord initiates a cascade of molecular and cellular events that generates a non-permissive environment for cell survival and axonal regeneration. Among these complex set of events are damage of the blood-brain barrier, edema formation, inflammation, oxidative stress, demyelination, reactive gliosis and apoptosis. The multiple events activated after SCI require a multi-active drug that could target most of these events and produce a permissive environment for cell survival, regeneration, vascular reorganization and synaptic formation. Tamoxifen, a selective estrogen receptor modulator, is an FDA approved drug with several neuroprotective properties that should be considered for the treatment of this devastating condition. Various investigators using different animal models and injury parameters have demonstrated the beneficial effects of this drug to improve functional locomotor recovery after SCI. Results suggest that the mechanism of action of Tamoxifen administration is to modulate anti-oxidant, anti-inflammatory and anti-gliotic responses. A gap of knowledge exists regarding the sex differences in response to Tamoxifen and the therapeutic window available to administer this treatment. In addition, the effects of Tamoxifen in axonal outgrowth or synapse formation needs to be investigated. This review will address some of the mechanisms activated by Tamoxifen after SCI and the results recently published by investigators in the field.

  3. Genome-wide functional screen identifies a compendium of genes affecting sensitivity to tamoxifen.

    Science.gov (United States)

    Mendes-Pereira, Ana M; Sims, David; Dexter, Tim; Fenwick, Kerry; Assiotis, Ioannis; Kozarewa, Iwanka; Mitsopoulos, Costas; Hakas, Jarle; Zvelebil, Marketa; Lord, Christopher J; Ashworth, Alan

    2012-02-21

    Therapies that target estrogen signaling have made a very considerable contribution to reducing mortality from breast cancer. However, resistance to tamoxifen remains a major clinical problem. Here we have used a genome-wide functional profiling approach to identify multiple genes that confer resistance or sensitivity to tamoxifen. Combining whole-genome shRNA screening with massively parallel sequencing, we have profiled the impact of more than 56,670 RNA interference reagents targeting 16,487 genes on the cellular response to tamoxifen. This screen, along with subsequent validation experiments, identifies a compendium of genes whose silencing causes tamoxifen resistance (including BAP1, CLPP, GPRC5D, NAE1, NF1, NIPBL, NSD1, RAD21, RARG, SMC3, and UBA3) and also a set of genes whose silencing causes sensitivity to this endocrine agent (C10orf72, C15orf55/NUT, EDF1, ING5, KRAS, NOC3L, PPP1R15B, RRAS2, TMPRSS2, and TPM4). Multiple individual genes, including NF1, a regulator of RAS signaling, also correlate with clinical outcome after tamoxifen treatment.

  4. Comparison of short-term estrogenicity tests for identification of hormone-disrupting chemicals

    DEFF Research Database (Denmark)

    Andersen, H R; Andersson, A M; Arnold, S F

    1999-01-01

    induced a strong estrogenic response in all test systems. Colchicine caused cytotoxicity only. Bisphenol A induced an estrogenic response in all assays. The results obtained for the remaining test compounds--tamoxifen, ICI 182.780, testosterone, bisphenol A dimethacrylate, 4-n-octylphenol, 4-n...

  5. The effects of breast cancer therapy on estrogen receptor signaling throughout the body

    NARCIS (Netherlands)

    Droog, M.

    2017-01-01

    Upon activation by estrogen, the Estrogen Receptor binds the chromatin and influences gene transcription. This ultimately leads to cell proliferation. About 75% of breast cancer patients express this hormonal receptor. These patients are often treated with tamoxifen, which competitively inhibits the

  6. Uncovering the Mechanism of ICI-Mediated Estrogen Receptor-Alpha Degradation

    Science.gov (United States)

    2008-10-01

    artifical sticky ends that would be generated by digestion with EcoRI. I am currently in the process of trying to ligate the insert into the digested...beneficial qualities in bone and the cardiovascular system. A better understanding of the mechanism by which ICI mediates ER degradation may lead to the

  7. Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-α–Mediated Ca2+ Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells

    Science.gov (United States)

    Wozniak, Ann L.; Bulayeva, Nataliya N.; Watson, Cheryl S.

    2005-01-01

    Xenoestrogens (XEs) are widespread in our environment and are known to have deleterious effects in animal (and perhaps human) populations. Acting as inappropriate estrogens, XEs are thought to interfere with endogenous estrogens such as estradiol (E2) to disrupt normal estrogenic signaling. We investigated the effects of E2 versus several XEs representing organochlorine pesticides (dieldrin, endosulfan, o′p′-dichlorodiphenylethylene), plastics manufacturing by-products/detergents (nonylphenol, bisphenol A), a phytoestrogen (coumestrol), and a synthetic estrogen (diethylstilbestrol) on the pituitary tumor cell subline GH3/B6/F10, previously selected for expression of high levels of membrane estrogen receptor-α. Picomolar to nanomolar concentrations of both E2 and XEs caused intracellular Ca2+ changes within 30 sec of administration. Each XE produced a unique temporal pattern of Ca2+ elevation. Removing Ca2+ from the extracellular solution abolished both spontaneous and XE-induced intracellular Ca2+ changes, as did 10 μM nifedipine. This suggests that XEs mediate their actions via voltage-dependent L-type Ca2+ channels in the plasma membrane. None of the Ca2+ fluxes came from intracellular Ca2+ stores. E2 and each XE also caused unique time- and concentration-dependent patterns of prolactin (PRL) secretion that were largely complete within 3 min of administration. PRL secretion was also blocked by nifedipine, demonstrating a correlation between Ca2+ influx and PRL secretion. These data indicate that at very low concentrations, XEs mediate membrane-initiated intracellular Ca2+ increases resulting in PRL secretion via a mechanism similar to that for E2, but with distinct patterns and potencies that could explain their abilities to disrupt endocrine functions. PMID:15811834

  8. Identification of putative estrogen receptor-mediated endocrine disrupting chemicals using QSAR- and structure-based virtual screening approaches

    International Nuclear Information System (INIS)

    Zhang, Liying; Sedykh, Alexander; Tripathi, Ashutosh; Zhu, Hao; Afantitis, Antreas; Mouchlis, Varnavas D.; Melagraki, Georgia; Rusyn, Ivan; Tropsha, Alexander

    2013-01-01

    Identification of endocrine disrupting chemicals is one of the important goals of environmental chemical hazard screening. We report on the development of validated in silico predictors of chemicals likely to cause estrogen receptor (ER)-mediated endocrine disruption to facilitate their prioritization for future screening. A database of relative binding affinity of a large number of ERα and/or ERβ ligands was assembled (546 for ERα and 137 for ERβ). Both single-task learning (STL) and multi-task learning (MTL) continuous quantitative structure–activity relationship (QSAR) models were developed for predicting ligand binding affinity to ERα or ERβ. High predictive accuracy was achieved for ERα binding affinity (MTL R 2 = 0.71, STL R 2 = 0.73). For ERβ binding affinity, MTL models were significantly more predictive (R 2 = 0.53, p < 0.05) than STL models. In addition, docking studies were performed on a set of ER agonists/antagonists (67 agonists and 39 antagonists for ERα, 48 agonists and 32 antagonists for ERβ, supplemented by putative decoys/non-binders) using the following ER structures (in complexes with respective ligands) retrieved from the Protein Data Bank: ERα agonist (PDB ID: 1L2I), ERα antagonist (PDB ID: 3DT3), ERβ agonist (PDB ID: 2NV7), and ERβ antagonist (PDB ID: 1L2J). We found that all four ER conformations discriminated their corresponding ligands from presumed non-binders. Finally, both QSAR models and ER structures were employed in parallel to virtually screen several large libraries of environmental chemicals to derive a ligand- and structure-based prioritized list of putative estrogenic compounds to be used for in vitro and in vivo experimental validation. - Highlights: • This is the largest curated dataset inclusive of ERα and β (the latter is unique). • New methodology that for the first time affords acceptable ERβ models. • A combination of QSAR and docking enables prediction of affinity and function. • The results

  9. Identification of putative estrogen receptor-mediated endocrine disrupting chemicals using QSAR- and structure-based virtual screening approaches

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liying; Sedykh, Alexander; Tripathi, Ashutosh [Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC (United States); Zhu, Hao [The Rutgers Center for Computational and Integrative Biology, Rutgers University, Camden, NJ (United States); Department of Chemistry, Rutgers University, Camden, NJ (United States); Afantitis, Antreas; Mouchlis, Varnavas D.; Melagraki, Georgia [NovaMechanics Ltd., Nicosia (Cyprus); Rusyn, Ivan, E-mail: iir@unc.edu [Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC (United States); Tropsha, Alexander, E-mail: alex_tropsha@unc.edu [Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC (United States)

    2013-10-01

    Identification of endocrine disrupting chemicals is one of the important goals of environmental chemical hazard screening. We report on the development of validated in silico predictors of chemicals likely to cause estrogen receptor (ER)-mediated endocrine disruption to facilitate their prioritization for future screening. A database of relative binding affinity of a large number of ERα and/or ERβ ligands was assembled (546 for ERα and 137 for ERβ). Both single-task learning (STL) and multi-task learning (MTL) continuous quantitative structure–activity relationship (QSAR) models were developed for predicting ligand binding affinity to ERα or ERβ. High predictive accuracy was achieved for ERα binding affinity (MTL R{sup 2} = 0.71, STL R{sup 2} = 0.73). For ERβ binding affinity, MTL models were significantly more predictive (R{sup 2} = 0.53, p < 0.05) than STL models. In addition, docking studies were performed on a set of ER agonists/antagonists (67 agonists and 39 antagonists for ERα, 48 agonists and 32 antagonists for ERβ, supplemented by putative decoys/non-binders) using the following ER structures (in complexes with respective ligands) retrieved from the Protein Data Bank: ERα agonist (PDB ID: 1L2I), ERα antagonist (PDB ID: 3DT3), ERβ agonist (PDB ID: 2NV7), and ERβ antagonist (PDB ID: 1L2J). We found that all four ER conformations discriminated their corresponding ligands from presumed non-binders. Finally, both QSAR models and ER structures were employed in parallel to virtually screen several large libraries of environmental chemicals to derive a ligand- and structure-based prioritized list of putative estrogenic compounds to be used for in vitro and in vivo experimental validation. - Highlights: • This is the largest curated dataset inclusive of ERα and β (the latter is unique). • New methodology that for the first time affords acceptable ERβ models. • A combination of QSAR and docking enables prediction of affinity and function.

  10. Chemopreventive and therapeutic activity of dietary blueberry against estrogen-mediated breast cancer.

    Science.gov (United States)

    Jeyabalan, Jeyaprakash; Aqil, Farrukh; Munagala, Radha; Annamalai, Lakshmanan; Vadhanam, Manicka V; Gupta, Ramesh C

    2014-05-07

    Berries are gaining increasing importance lately for their chemopreventive and therapeutic potential against several cancers. In earlier studies, a blueberry-supplemented diet has shown protection against 17β-estradiol (E2)-mediated mammary tumorigenesis. This study tested both preventive and therapeutic activities of diet supplemented with whole blueberry powder (50:50 blend of Tifblue and Rubel). Animals received 5% blueberry diet, either 2 weeks prior to or 12 weeks after E2 treatment in preventive and therapeutic groups, respectively. Both interventions delayed the tumor latency for palpable mammary tumors by 28 and 37 days, respectively. Tumor volume and multiplicity were also reduced significantly in both modes. The effect on mammary tumorigenesis was largely due to down-regulation of CYP 1A1 and ER-α gene expression and also favorable modulation of microRNA (miR-18a and miR-34c) levels. These data suggest that the blueberry blend tested is effective in inhibiting E2-mediated mammary tumorigenesis in both preventive and therapeutic modes.

  11. Imaging of estrogen receptors with radiolabeled-GAP-EDL

    Energy Technology Data Exchange (ETDEWEB)

    Oh, C. S. [The University of Texas M.D. Anderson Cancer Center Houston, Houston (United States); Yang, David J.; Kim, D. E.; Kim, C. K [Wonkwang Univ. College of Medicine, Iksan (Korea, Republic of)

    2007-07-01

    To evaluate the feasibility of using 99mTc-glutamate peptide estradiol(GAP-EDL) in imaging estrogen receptor positive (ER + ) tumor bearing animals. Cellular uptake studies of 99mTc-GAP-EDL was conduct in ER(+) breast cancer cell line (MCF7, 13762 and T47D) in the presence and absence of diethylstilbestrol or tamoxifen. Biodistribution and imaging studies were conducted in rats bearing 13762 breast cancer cells. After posterior limb tumor size reached 8-10 mm, the rats were injected intravenously with 99mTc-GAP-EDL or 99mTc-GAP (10uCi/rat, 10ugm/rat for biodistribution and 300uCi/rat for imaging) and the data were collected at 0.5-4 hrs. 99mTc-DTPA, renal imaging agent, was used for comparison due to its similar carboxylic chelation. To ascertain whether the tumor uptake by 99mTc-GAP-EDL was via an estrogen receptor-mediated process, rats was pretreated with diehystillbestrol (n=3, 10mg/kr, iv) and imaged at 0.5-4.0 hrs. In vitro studies revealed that there was an increased uptake of 99mTc-GAP-EDL compared with that of 99mTc-GAP. There was 10-40% decreased uptake in MCF-7 and T47D cells treated with diethylstilbestrol or tamoxifen compared to untreated 99mTc-GAP-EDL. Western blot analysis showed that there was an ERK2 phosphorylation process in 13762 cells. Biodistribution studies showed that tumor uptake, tumor-to-blood and tumor-to muscle count density ration in 99mTc-GAP-EDL groups were significantly higher than in 99mTc-GAP groups at 4hrs post-administration. Tumor-to muscle ratios at 0.5-4 hrs were 1.67-2.95 and 1.26-1.75 for 99mTc-GAP-EDL and 99mTc-DTPA, respectively. In blocking studies, tumor-to muscle ratios were 1.98-2.39 and 1.21-1.63 for 99mTc-GAP-EDL and blocked groups, respectively. The finding indicate that tumor uptake of 99mTc-GAP-EDL was via an estrogen receptor-mediated process, subsequently involved in MAP kinase (MAPK) activation as indicated by ERK2 phosphorylation. The finding indicate that 99mTc-GAP-EDL is a functional ER(+) imaging agent.

  12. Global identification of genes regulated by estrogen signaling and demethylation in MCF-7 breast cancer cells

    International Nuclear Information System (INIS)

    Putnik, Milica; Zhao, Chunyan; Gustafsson, Jan-Åke; Dahlman-Wright, Karin

    2012-01-01

    Highlights: ► Estrogen signaling and demethylation can both control gene expression in breast cancers. ► Cross-talk between these mechanisms is investigated in human MCF-7 breast cancer cells. ► 137 genes are influenced by both 17β-estradiol and demethylating agent 5-aza-2′-deoxycytidine. ► A set of genes is identified as targets of both estrogen signaling and demethylation. ► There is no direct molecular interplay of mediators of estrogen and epigenetic signaling. -- Abstract: Estrogen signaling and epigenetic modifications, in particular DNA methylation, are involved in regulation of gene expression in breast cancers. Here we investigated a potential regulatory cross-talk between these two pathways by identifying their common target genes and exploring underlying molecular mechanisms in human MCF-7 breast cancer cells. Gene expression profiling revealed that the expression of approximately 140 genes was influenced by both 17β-estradiol (E2) and a demethylating agent 5-aza-2′-deoxycytidine (DAC). Gene ontology (GO) analysis suggests that these genes are involved in intracellular signaling cascades, regulation of cell proliferation and apoptosis. Based on previously reported association with breast cancer, estrogen signaling and/or DNA methylation, CpG island prediction and GO analysis, we selected six genes (BTG3, FHL2, PMAIP1, BTG2, CDKN1A and TGFB2) for further analysis. Tamoxifen reverses the effect of E2 on the expression of all selected genes, suggesting that they are direct targets of estrogen receptor. Furthermore, DAC treatment reactivates the expression of all selected genes in a dose-dependent manner. Promoter CpG island methylation status analysis revealed that only the promoters of BTG3 and FHL2 genes are methylated, with DAC inducing demethylation, suggesting DNA methylation directs repression of these genes in MCF-7 cells. In a further analysis of the potential interplay between estrogen signaling and DNA methylation, E2 treatment

  13. Reprogramming of the ERRα and ERα target gene landscape triggers tamoxifen resistance in breast cancer.

    Science.gov (United States)

    Thewes, Verena; Simon, Ronald; Schroeter, Petra; Schlotter, Magdalena; Anzeneder, Tobias; Büttner, Reinhard; Benes, Vladimir; Sauter, Guido; Burwinkel, Barbara; Nicholson, Robert I; Sinn, Hans-Peter; Schneeweiss, Andreas; Deuschle, Ulrich; Zapatka, Marc; Heck, Stefanie; Lichter, Peter

    2015-02-15

    Endocrine treatment regimens for breast cancer that target the estrogen receptor-α (ERα) are effective, but acquired resistance remains a limiting drawback. One mechanism of acquired resistance that has been hypothesized is functional substitution of the orphan receptor estrogen-related receptor-α (ERRα) for ERα. To examine this hypothesis, we analyzed ERRα and ERα in recurrent tamoxifen-resistant breast tumors and conducted a genome-wide target gene profiling analysis of MCF-7 breast cancer cell populations that were sensitive or resistant to tamoxifen treatment. This analysis uncovered a global redirection in the target genes controlled by ERα, ERRα, and their coactivator AIB1, defining a novel set of target genes in tamoxifen-resistant cells. Beyond differences in the ERα and ERRα target gene repertoires, both factors were engaged in similar pathobiologic processes relevant to acquired resistance. Functional analyses confirmed a requirement for ERRα in tamoxifen- and fulvestrant-resistant MCF-7 cells, with pharmacologic inhibition of ERRα sufficient to partly restore sensitivity to antiestrogens. In clinical specimens (n = 1041), increased expression of ERRα was associated with enhanced proliferation and aggressive disease parameters, including increased levels of p53 in ERα-positive cases. In addition, increased ERRα expression was linked to reduced overall survival in independent tamoxifen-treated patient cohorts. Taken together, our results suggest that ERα and ERRα cooperate to promote endocrine resistance, and they provide a rationale for the exploration of ERRα as a candidate drug target to treat endocrine-resistant breast cancer. ©2015 American Association for Cancer Research.

  14. CITED2 modulates estrogen receptor transcriptional activity in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Wen Min; Doucet, Michele; Huang, David; Weber, Kristy L.; Kominsky, Scott L., E-mail: kominsc@jhmi.edu

    2013-07-26

    Highlights: •The effects of elevated CITED2 on ER function in breast cancer cells are examined. •CITED2 enhances cell growth in the absence of estrogen and presence of tamoxifen. •CITED2 functions as a transcriptional co-activator of ER in breast cancer cells. -- Abstract: Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2) is a member of the CITED family of non-DNA binding transcriptional co-activators of the p300/CBP-mediated transcription complex. Previously, we identified CITED2 as being overexpressed in human breast tumors relative to normal mammary epithelium. Upon further investigation within the estrogen receptor (ER)-positive subset of these breast tumor samples, we found that CITED2 mRNA expression was elevated in those associated with poor survival. In light of this observation, we investigated the effect of elevated CITED2 levels on ER function. While ectopic overexpression of CITED2 in three ER-positive breast cancer cell lines (MCF-7, T47D, and CAMA-1) did not alter cell proliferation in complete media, growth was markedly enhanced in the absence of exogenous estrogen. Correspondingly, cells overexpressing CITED2 demonstrated reduced sensitivity to the growth inhibitory effects of the selective estrogen receptor modulator, 4-hydroxytamoxifen. Subsequent studies revealed that basal ER transcriptional activity was elevated in CITED2-overexpressing cells and was further increased upon the addition of estrogen. Similarly, basal and estrogen-induced expression of the ER-regulated genes trefoil factor 1 (TFF1) and progesterone receptor (PGR) was higher in cells overexpressing CITED2. Concordant with this observation, ChIP analysis revealed higher basal levels of CITED2 localized to the TFF-1 and PGR promoters in cells with ectopic overexpression of CITED2, and these levels were elevated further in response to estrogen stimulation. Taken together, these data indicate that CITED2 functions as a transcriptional co

  15. CITED2 modulates estrogen receptor transcriptional activity in breast cancer cells

    International Nuclear Information System (INIS)

    Lau, Wen Min; Doucet, Michele; Huang, David; Weber, Kristy L.; Kominsky, Scott L.

    2013-01-01

    Highlights: •The effects of elevated CITED2 on ER function in breast cancer cells are examined. •CITED2 enhances cell growth in the absence of estrogen and presence of tamoxifen. •CITED2 functions as a transcriptional co-activator of ER in breast cancer cells. -- Abstract: Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2) is a member of the CITED family of non-DNA binding transcriptional co-activators of the p300/CBP-mediated transcription complex. Previously, we identified CITED2 as being overexpressed in human breast tumors relative to normal mammary epithelium. Upon further investigation within the estrogen receptor (ER)-positive subset of these breast tumor samples, we found that CITED2 mRNA expression was elevated in those associated with poor survival. In light of this observation, we investigated the effect of elevated CITED2 levels on ER function. While ectopic overexpression of CITED2 in three ER-positive breast cancer cell lines (MCF-7, T47D, and CAMA-1) did not alter cell proliferation in complete media, growth was markedly enhanced in the absence of exogenous estrogen. Correspondingly, cells overexpressing CITED2 demonstrated reduced sensitivity to the growth inhibitory effects of the selective estrogen receptor modulator, 4-hydroxytamoxifen. Subsequent studies revealed that basal ER transcriptional activity was elevated in CITED2-overexpressing cells and was further increased upon the addition of estrogen. Similarly, basal and estrogen-induced expression of the ER-regulated genes trefoil factor 1 (TFF1) and progesterone receptor (PGR) was higher in cells overexpressing CITED2. Concordant with this observation, ChIP analysis revealed higher basal levels of CITED2 localized to the TFF-1 and PGR promoters in cells with ectopic overexpression of CITED2, and these levels were elevated further in response to estrogen stimulation. Taken together, these data indicate that CITED2 functions as a transcriptional co

  16. Tamoxifen Isomers and Metabolites Exhibit Distinct Affinity and Activity at Cannabinoid Receptors: Potential Scaffold for Drug Development.

    Science.gov (United States)

    Ford, Benjamin M; Franks, Lirit N; Radominska-Pandya, Anna; Prather, Paul L

    2016-01-01

    Tamoxifen (Tam) is a selective estrogen receptor (ER) modulator (SERM) that is an essential drug to treat ER-positive breast cancer. Aside from known actions at ERs, recent studies have suggested that some SERMs like Tam also exhibit novel activity at cannabinoid subtype 1 and 2 receptors (CB1R and CB2Rs). Interestingly, cis- (E-Tam) and trans- (Z-Tam) isomers of Tam exhibit over a 100-fold difference in affinity for ERs. Therefore, the current study assessed individual isomers of Tam and subsequent cytochrome P450 metabolic products, 4-hydroxytamoxifen (4OHT) and 4-hydroxy-N-desmethyl tamoxifen (End) for affinity and activity at CBRs. Results showed that Z-4OHT, but not Z-Tam or Z-End, exhibits higher affinity for both CB1 and CB2Rs relative to the E-isomer. Furthermore, Z- and E-isomers of Tam and 4OHT show slightly higher affinity for CB2Rs, while both End isomers are relatively CB1R-selective. When functional activity was assessed by G-protein activation and regulation of the downstream effector adenylyl cyclase, all isomers examined act as full CB1 and CB2R inverse agonists. Interestingly, Z-Tam appears to be more efficacious than the full inverse agonist AM630 at CB2Rs, while both Z-Tam and Z-End exhibit characteristics of insurmountable antagonism at CB1 and CB2Rs, respectively. Collectively, these results suggest that the SERMs Tam, 4OHT and End elicit ER-independent actions via CBRs in an isomer-specific manner. As such, this novel structural scaffold might be used to develop therapeutically useful drugs for treatment of a variety of diseases mediated via CBRs.

  17. Tamoxifen Isomers and Metabolites Exhibit Distinct Affinity and Activity at Cannabinoid Receptors: Potential Scaffold for Drug Development.

    Directory of Open Access Journals (Sweden)

    Benjamin M Ford

    Full Text Available Tamoxifen (Tam is a selective estrogen receptor (ER modulator (SERM that is an essential drug to treat ER-positive breast cancer. Aside from known actions at ERs, recent studies have suggested that some SERMs like Tam also exhibit novel activity at cannabinoid subtype 1 and 2 receptors (CB1R and CB2Rs. Interestingly, cis- (E-Tam and trans- (Z-Tam isomers of Tam exhibit over a 100-fold difference in affinity for ERs. Therefore, the current study assessed individual isomers of Tam and subsequent cytochrome P450 metabolic products, 4-hydroxytamoxifen (4OHT and 4-hydroxy-N-desmethyl tamoxifen (End for affinity and activity at CBRs. Results showed that Z-4OHT, but not Z-Tam or Z-End, exhibits higher affinity for both CB1 and CB2Rs relative to the E-isomer. Furthermore, Z- and E-isomers of Tam and 4OHT show slightly higher affinity for CB2Rs, while both End isomers are relatively CB1R-selective. When functional activity was assessed by G-protein activation and regulation of the downstream effector adenylyl cyclase, all isomers examined act as full CB1 and CB2R inverse agonists. Interestingly, Z-Tam appears to be more efficacious than the full inverse agonist AM630 at CB2Rs, while both Z-Tam and Z-End exhibit characteristics of insurmountable antagonism at CB1 and CB2Rs, respectively. Collectively, these results suggest that the SERMs Tam, 4OHT and End elicit ER-independent actions via CBRs in an isomer-specific manner. As such, this novel structural scaffold might be used to develop therapeutically useful drugs for treatment of a variety of diseases mediated via CBRs.

  18. Estrogens, selective estrogen receptor modulators, and a selective estrogen receptor down-regulator inhibit endothelial production of tissue factor pathway inhibitor 1

    Directory of Open Access Journals (Sweden)

    Ree Anne

    2006-10-01

    Full Text Available Abstract Background Hormone therapy, oral contraceptives, and tamoxifen increase the risk of thrombotic disease. These compounds also reduce plasma content of tissue factor pathway inhibitor-1 (TFPI, which is the physiological inhibitor of the tissue factor pathway of coagulation. The current aim was to study if estrogens and estrogen receptor (ER modulators may inhibit TFPI production in cultured endothelial cells and, if so, identify possible mechanisms involved. Methods Human endothelial cell cultures were treated with 17β-estradiol (E2, 17α-ethinylestradiol (EE2, tamoxifen, raloxifene, or fulvestrant. Protein levels of TFPI in cell media and cell lysates were measured by an enzyme-linked immunosorbent assay, and TFPI mRNA levels were assessed by quantitative PCR. Expression of ERα was analysed by immunostaining. Results All compounds (each in a concentration of 10 nM reduced TFPI in cell medium, by 34% (E2, 21% (EE2, 16% (tamoxifen, and 28% (raloxifene, respectively, with identical inhibitory effects on cellular TFPI levels. Expression of TFPI mRNA was principally unchanged. Treatment with fulvestrant, which was also associated with down-regulation of secreted TFPI (9% with 10 nM and 26% with 1000 nM, abolished the TFPI-inhibiting effect of raloxifene, but not of the other compounds. Notably, the combination of 1000 nM fulvestrant and 10 nM raloxifene increased TFPI secretion, and, conversely, 10 nM of either tamoxifen or raloxifene seemed to partly (tamoxifen or fully (raloxifene counteract the inhibitory effect of 1000 nM fulvestrant. The cells did not express the regular nuclear 66 kDa ERα, but instead a 45 kDa ERα, which was not regulated by estrogens or ER modulators. Conclusion E2, EE2, tamoxifen, raloxifene, and fulvestrant inhibited endothelial production of TFPI by a mechanism apparently independent of TFPI transcription.

  19. The effects of soy and tamoxifen on apoptosis in the hippocampus and dentate gyrus in a pentylenetetrazole-induced seizure model of ovariectomized rats.

    Science.gov (United States)

    Ebrahimzadeh-Bideskan, Ali Reza; Mansouri, Somaieh; Ataei, Mariam Lale; Jahanshahi, Mehrdad; Hosseini, Mahmoud

    2018-03-01

    The effects of tamoxifen and soy on apoptosis of the hippocampus and dentate gyrus of ovariectomized rats after repeated seizures were investigated. Female rats were divided into: (1) Control, (2) Sham, (3) Sham-Tamoxifen (Sham-T), (4) Ovariectomized (OVX), (5) OVX-Tamoxifen (OVX-T), (6)OVX-Soy(OVX-S) and (7) OVX-S-T. The animals in the OVX-S, OVX-T and OVX-S-T groups received soy extract (60 mg/kg; i.p.), tamoxifen (10 mg/kg) or both for 2 weeks before induction of seizures. The animals in these groups additionally received the mentioned treatments before each injection of pentylenetetrazole (PTZ; 40 mg/kg) for 6 days. The animals in the Sham and OVX groups received a vehicle of tamoxifen and soy. A significant decrease in the seizure score and TUNEL-positive neurons was seen in the OVX group compared to the Sham (P < 0.001). The animals in both the OVX-T and OVX-S groups had a significantly higher seizure score as well as number of TUNEL-positive neurons compared to the OVX group (P < 0.01-P < 0.001). Co-treatment of the OVX rats by the extract and tamoxifen decreased the seizure score and number of TUNEL-positive neurons compared to OVX-S (P < 0.001). Treatment of the OVX rats by either soy or tamoxifen increased the seizure score as well as the number of TUNEL-positive neurons in the hippocampal formation. Co-administration of tamoxifen and soy extract inhibited the effects of the soy extract and tamoxifen when they were administered alone. It might be suggested that both soy and tamoxifen have agonistic effects on estrogen receptors by changing the seizure severity.

  20. Purple sweet potato color attenuates domoic acid-induced cognitive deficits by promoting estrogen receptor-α-mediated mitochondrial biogenesis signaling in mice.

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    Lu, Jun; Wu, Dong-Mei; Zheng, Yuan-Lin; Hu, Bin; Cheng, Wei; Zhang, Zi-Feng

    2012-02-01

    Recent findings suggest that endoplasmic reticulum stress may be involved in the pathogenesis of domoic acid-induced neurodegeneration. Purple sweet potato color, a class of naturally occurring anthocyanins, has beneficial health and biological effects. Recent studies have also shown that anthocyanins have estrogenic activity and can enhance estrogen receptor-α expression. In this study, we evaluated the effect of purple sweet potato color on cognitive deficits induced by hippocampal mitochondrial dysfunction in domoic acid-treated mice and explored the potential mechanisms underlying this effect. Our results showed that the oral administration of purple sweet potato color to domoic acid-treated mice significantly improved their behavioral performance in a step-through passive avoidance task and a Morris water maze task. These improvements were mediated, at least in part, by a stimulation of estrogen receptor-α-mediated mitochondrial biogenesis signaling and by decreases in the expression of p47phox and gp91phox. Decreases in reactive oxygen species and protein carbonylation were also observed, along with a blockade of the endoplasmic reticulum stress pathway. Furthermore, purple sweet potato color significantly suppressed endoplasmic reticulum stress-induced apoptosis, which prevented neuron loss and restored the expression of memory-related proteins. However, knockdown of estrogen receptor-α using short hairpin RNA only partially blocked the neuroprotective effects of purple sweet potato color in the hippocampus of mice cotreated with purple sweet potato color and domoic acid, indicating that purple sweet potato color acts through multiple pathways. These results suggest that purple sweet potato color could be a possible candidate for the prevention and treatment of cognitive deficits in excitotoxic and other brain disorders. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  1. Novel Carbonyl Analogs of Tamoxifen: Design, Synthesis, and Biological Evaluation

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    Konstantinos M. Kasiotis

    2017-09-01

    Full Text Available Aim of this work was to provide tamoxifen analogs with enhanced estrogen receptor (ER binding affinity. Hence, several derivatives were prepared using an efficient triarylethylenes synthetic protocol. The novel compounds bioactivity was evaluated through the determination of their receptor binding affinity and their agonist/antagonist activity against breast cancer tissue using a MCF-7 cell-based assay. Phenyl esters 6a,b and 8a,b exhibited binding affinity to both ERα and ERβ higher than 4-hydroxytamoxifen while compounds 13 and 14 have shown cellular antiestrogenic activity similar to 4-hydroxytamoxifen and the known ER inhibitor ICI182,780. Theoretical calculations and molecular modeling were applied to investigate, support and explain the biological profile of the new compounds. The relevant data indicated an agreement between calculations and demonstrated biological activity allowing to extract useful structure-activity relationships. Results herein underline that modifications of tamoxifen structure still provide molecules with substantial activity, as portrayed in the inhibition of MCF-7 cells proliferation.

  2. The evaluation of in vitro effect of daunorubicin and tamoxifen in ehrlich ascites tumour (EAT) cells

    International Nuclear Information System (INIS)

    Topcul, M.; Topcul, F.; Oezalpan, A.

    2001-01-01

    In the most countries, breast cancer is still the most important cancer among women. It is known that Ehrlich Ascites Tumour is experimental breast cancer model in animal. The cells used in the study are hyper diploid line of Ehrlich Ascites Tumour (EAT) cells, initially provided to us from Institute of Pathology, Koln University. In the present study, an hyper diploid line which is estrogen receptor positive was used. An anthracycline-derived antibiotic, Daunorubicin (DNR, Cerubidine) is one of the clinically used anticancer drugs. DNR has been used alone or in combination with other cytotoxic agents against a variety of animal and human tumours. In vitro cell culture studies show that DNR enters the cell nuclei, inhibits nucleic acid synthesis, and arrest cell division. Tamoxifen (TAM, Nolvadex) is a semi-synthetical estrogen antagonist, used in the management of pre and post menopausal breast cancer. This drug bind to intracellular estrogen receptors, and prevents endogenous estrogens from binding to their own receptors. It is known that Ehrlich Ascites Tumour is experimental breast cancer model in animal. The cells used in the study are hyper diploid line of EAT cells initially provided to us from Institute of Pathology, Koln University. In the present study, an hyper diploid line which is Estrogen Receptor (+) was used. Estrogen Receptor levels were studied by the methods of Lippman and Huff and Raynaud et al. with minor modifications. Estrogen Receptor activity as demonstrated by dextran-coated charcoal technique is closely correlated with the clinical ability of Tamoxifen to inhibit tumour growth

  3. Early and late tamoxifen resistance in breast cancer

    Directory of Open Access Journals (Sweden)

    Abu Rabi Z.

    2010-01-01

    Full Text Available In our study we investigated the role of the estrogen receptor (ER, progesterone receptor (PR and clinicohistological parameters in breast cancer patients treated with tamoxifen during the early (2.5 years vs. late (2.5-5 years follow-up. The negative status of both ER and PR and tumors equal to or bigger than 2 cm defined the phenotypes and consequently the groups of patients with the worst clinical course of the disease: ER-negative PR-negative, ER-negative pT2 and PR-negative pT2. These high-risk subgroups were related to early follow-up indicating de novo resistance. It is relevant to point out that examined predictive indicators did not show significant importance in the late follow-up study.

  4. Equol enhances tamoxifen’s anti-tumor activity by induction of caspase-mediated apoptosis in MCF-7 breast cancer cells

    International Nuclear Information System (INIS)

    Charalambous, Christiana; Pitta, Chara A; Constantinou, Andreas I

    2013-01-01

    Soy phytoestrogens, such as daidzein and its metabolite equol, have been proposed to be responsible for the low breast cancer rate in Asian women. Since the majority of estrogen receptor positive breast cancer patients are treated with tamoxifen, the basic objective of this study is to determine whether equol enhances tamoxifen’s anti-tumor effect, and to identify the molecular mechanisms involved. For this purpose, we examined the individual and combined effects of equol and tamoxifen on the estrogen-dependent MCF-7 breast cancer cells using viability assays, annexin-V/PI staining, cell cycle and western blot analysis. We found that equol (>50 μM) and 4-hydroxy-tamoxifen (4-OHT; >100 nM) significantly reduced the MCF-7 cell viability. Furthermore, the combination of equol (100 μM) and 4-OHT (10 μM) induced apoptosis more effectively than each compound alone. Subsequent treatment of MCF-7 cells with the pan-caspase inhibitor Z-VAD-FMK inhibited equol- and 4-OHT-mediated apoptosis, which was accompanied by PARP and α-fodrin cleavage, indicating that apoptosis is mainly caspase-mediated. These compounds also induced a marked reduction in the bcl-2:bax ratio, which was accompanied by caspase-9 and caspase-7 activation and cytochrome-c release to the cytosol. Taken together, these data support the notion that the combination of equol and tamoxifen activates the intrinsic apoptotic pathway more efficiently than each compound alone. Consequently, equol may be used therapeutically in combination treatments and clinical studies to enhance tamoxifen’s effect by providing additional protection against estrogen-responsive breast cancers

  5. The role of the addition of ovarian suppression to tamoxifen in young women with hormone-sensitive breast cancer who remain premenopausal or regain menstruation after chemotherapy (ASTRRA): study protocol for a randomized controlled trial and progress

    International Nuclear Information System (INIS)

    Kim, Hyun-Ah; Ahn, Sei Hyun; Nam, Seok Jin; Park, Seho; Ro, Jungsil

    2016-01-01

    Ovarian function suppression (OFS) has been shown to be effective as adjuvant endocrine therapy in premenopausal women with hormone receptor-positive breast cancer. However, it is currently unclear if addition of OFS to standard tamoxifen therapy after completion of adjuvant chemotherapy results in a survival benefit. In 2008, the Korean Breast Cancer Society Study Group initiated the ASTRRA randomized phase III trial to evaluate the efficacy of OFS in addition to standard tamoxifen treatment in hormone receptor-positive breast cancer patients who remain or regain premenopausal status after chemotherapy. Premenopausal women with estrogen receptor-positive breast cancer treated with definitive surgery were enrolled after completion of neoadjuvant or adjuvant chemotherapy. Ovarian function was assessed at the time of enrollment and every 6 months for 2 years by follicular-stimulating hormone levels and bleeding history. If ovarian function was confirmed as premenopausal status, the patient was randomized to receive 2 years of goserelin plus 5 years of tamoxifen treatment or 5 years of tamoxifen alone. The primary end point will be the comparison of the 5-year disease-free survival rates between the OFS and tamoxifen alone groups. Patient recruitment was finished on March 2014 with the inclusion of a total of 1483 patients. The interim analysis will be performed at the time of the observation of the 187th event. This study will provide evidence of the benefit of OFS plus tamoxifen compared with tamoxifen only in premenopausal patients with estrogen receptor-positive breast cancer treated with chemotherapy

  6. ACE-2/Ang1-7/Mas cascade mediates ACE inhibitor, captopril, protective effects in estrogen-deficient osteoporotic rats.

    Science.gov (United States)

    Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S

    2017-08-01

    The local role of the renin angiotensin system (RAS) was documented recently beside its conventional systemic functions. Studies showed that the effector angiotensin II (AngII) alters bone health, while inhibition of the angiotensin converting enzyme (ACE-1) preserved these effects. The newly identified Ang1-7 exerts numerous beneficial effects opposing the AngII. Thus, the current study examines the role of Ang1-7 in mediating the osteo-preservative effects of ACEI (captopril) through the G-protein coupled Mas receptor using an ovariectomized (OVX) rat model of osteoporosis. 8 weeks after the surgical procedures, captopril was administered orally (40mgkg -1 d -1 ), while the specific Mas receptor blocker (A-779) was delivered at infusion rate of 400ngkg -1 min -1 for 6 weeks. Bone metabolic markers were measured in serum and urine. Minerals concentrations were quantified in serum, urine and femoral bones by inductive coupled plasma mass spectroscopy (ICP-MS). Trabecular and cortical morphometry was analyzed in the right distal femurs using micro-CT. Finally, the expressions of RAS peptides, enzymes and receptors along with the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) were determined femurs heads. OVX animals markedly showed altered bone metabolism and mineralization along with disturbed bone micro-structure. Captopril significantly restored the metabolic bone bio-markers and corrected Ca 2+ and P values in urine and bones of estrogen deficient rats. Moreover, the trabecular and cortical morphometric features were repaired by captopril in OVX groups. Captopril also improved the expressions of ACE-2, Ang1-7, Mas and OPG, while abolished OVX-induced up-regulation of ACE-1, AngII, Ang type 1 receptor (AT1R) and RANKL. Inhibition of Ang1-7 cascade by A-779 significantly eradicated captopril protective effects on bone metabolism, mineralization and micro-structure. A-779 also restored OVX effects on RANKL expression and ACE-1/AngII/AT1R

  7. Antioxidant-mediated up-regulation of OGG1 via NRF2 induction is associated with inhibition of oxidative DNA damage in estrogen-induced breast cancer

    International Nuclear Information System (INIS)

    Singh, Bhupendra; Chatterjee, Anwesha; Ronghe, Amruta M; Bhat, Nimee K; Bhat, Hari K

    2013-01-01

    Estrogen metabolism-mediated oxidative stress is suggested to play an important role in estrogen-induced breast carcinogenesis. We have earlier demonstrated that antioxidants, vitamin C (Vit C) and butylated hydroxyanisole (BHA) inhibit 17β-estradiol (E2)-mediated oxidative stress and oxidative DNA damage, and breast carcinogenesis in female August Copenhagen Irish (ACI) rats. The objective of the present study was to characterize the mechanism by which above antioxidants prevent DNA damage during breast carcinogenesis. Female ACI rats were treated with E2; Vit C; Vit C + E2; BHA; and BHA + E2 for up to 240 days. mRNA and protein levels of a DNA repair enzyme 8-Oxoguanine DNA glycosylase (OGG1) and a transcription factor NRF2 were quantified in the mammary and mammary tumor tissues of rats after treatment with E2 and compared with that of rats treated with antioxidants either alone or in combination with E2. The expression of OGG1 was suppressed in mammary tissues and in mammary tumors of rats treated with E2. Expression of NRF2 was also significantly suppressed in E2-treated mammary tissues and in mammary tumors. Vitamin C or BHA treatment prevented E2-mediated decrease in OGG1 and NRF2 levels in the mammary tissues. Chromatin immunoprecipitation analysis confirmed that antioxidant-mediated induction of OGG1 was through increased direct binding of NRF2 to the promoter region of OGG1. Studies using silencer RNA confirmed the role of OGG1 in inhibition of oxidative DNA damage. Our studies suggest that antioxidants Vit C and BHA provide protection against oxidative DNA damage and E2-induced mammary carcinogenesis, at least in part, through NRF2-mediated induction of OGG1

  8. SRC drives growth of antiestrogen resistant breast cancer cell lines and is a marker for reduced benefit of tamoxifen treatment.

    Science.gov (United States)

    Larsen, Sarah L; Laenkholm, Anne-Vibeke; Duun-Henriksen, Anne Katrine; Bak, Martin; Lykkesfeldt, Anne E; Kirkegaard, Tove

    2015-01-01

    The underlying mechanisms leading to antiestrogen resistance in estrogen-receptor α (ER)-positive breast cancer is still poorly understood. The aim of this study was therefore to identify biomarkers and novel treatments for antiestrogen resistant breast cancer. We performed a kinase inhibitor screen on antiestrogen responsive T47D breast cancer cells and T47D-derived tamoxifen and fulvestrant resistant cell lines. We found that dasatinib, a broad-spectrum kinase inhibitor, inhibited growth of the antiestrogen resistant cells compared to parental T47D cells. Furthermore western blot analysis showed increased expression and phosphorylation of Src in the resistant cells and that dasatinib inhibited phosphorylation of Src and also signaling via Akt and Erk in all cell lines. Immunoprecipitation revealed Src: ER complexes only in the parental T47D cells. In fulvestrant resistant cells, Src formed complexes with the Human Epidermal growth factor Receptor (HER)1 and HER2. Neither HER receptors nor ER were co-precipitated with Src in the tamoxifen resistant cell lines. Compared to treatment with dasatinib alone, combined treatment with dasatinib and fulvestrant had a stronger inhibitory effect on tamoxifen resistant cell growth, whereas dasatinib in combination with tamoxifen had no additive inhibitory effect on fulvestrant resistant growth. When performing immunohistochemical staining on 268 primary tumors from breast cancer patients who had received tamoxifen as first line endocrine treatment, we found that membrane expression of Src in the tumor cells was significant associated with reduced disease-free and overall survival. In conclusion, Src was identified as target for treatment of antiestrogen resistant T47D breast cancer cells. For tamoxifen resistant T47D cells, combined treatment with dasatinib and fulvestrant was superior to treatment with dasatinib alone. Src located at the membrane has potential as a new biomarker for reduced benefit of tamoxifen.

  9. SRC drives growth of antiestrogen resistant breast cancer cell lines and is a marker for reduced benefit of tamoxifen treatment.

    Directory of Open Access Journals (Sweden)

    Sarah L Larsen

    Full Text Available The underlying mechanisms leading to antiestrogen resistance in estrogen-receptor α (ER-positive breast cancer is still poorly understood. The aim of this study was therefore to identify biomarkers and novel treatments for antiestrogen resistant breast cancer. We performed a kinase inhibitor screen on antiestrogen responsive T47D breast cancer cells and T47D-derived tamoxifen and fulvestrant resistant cell lines. We found that dasatinib, a broad-spectrum kinase inhibitor, inhibited growth of the antiestrogen resistant cells compared to parental T47D cells. Furthermore western blot analysis showed increased expression and phosphorylation of Src in the resistant cells and that dasatinib inhibited phosphorylation of Src and also signaling via Akt and Erk in all cell lines. Immunoprecipitation revealed Src: ER complexes only in the parental T47D cells. In fulvestrant resistant cells, Src formed complexes with the Human Epidermal growth factor Receptor (HER1 and HER2. Neither HER receptors nor ER were co-precipitated with Src in the tamoxifen resistant cell lines. Compared to treatment with dasatinib alone, combined treatment with dasatinib and fulvestrant had a stronger inhibitory effect on tamoxifen resistant cell growth, whereas dasatinib in combination with tamoxifen had no additive inhibitory effect on fulvestrant resistant growth. When performing immunohistochemical staining on 268 primary tumors from breast cancer patients who had received tamoxifen as first line endocrine treatment, we found that membrane expression of Src in the tumor cells was significant associated with reduced disease-free and overall survival. In conclusion, Src was identified as target for treatment of antiestrogen resistant T47D breast cancer cells. For tamoxifen resistant T47D cells, combined treatment with dasatinib and fulvestrant was superior to treatment with dasatinib alone. Src located at the membrane has potential as a new biomarker for reduced benefit of

  10. Src Drives Growth of Antiestrogen Resistant Breast Cancer Cell Lines and Is a Marker for Reduced Benefit of Tamoxifen Treatment

    Science.gov (United States)

    Larsen, Sarah L.; Laenkholm, Anne-Vibeke; Duun-Henriksen, Anne Katrine; Bak, Martin; Lykkesfeldt, Anne E.; Kirkegaard, Tove

    2015-01-01

    The underlying mechanisms leading to antiestrogen resistance in estrogen-receptor α (ER)-positive breast cancer is still poorly understood. The aim of this study was therefore to identify biomarkers and novel treatments for antiestrogen resistant breast cancer. We performed a kinase inhibitor screen on antiestrogen responsive T47D breast cancer cells and T47D-derived tamoxifen and fulvestrant resistant cell lines. We found that dasatinib, a broad-spectrum kinase inhibitor, inhibited growth of the antiestrogen resistant cells compared to parental T47D cells. Furthermore western blot analysis showed increased expression and phosphorylation of Src in the resistant cells and that dasatinib inhibited phosphorylation of Src and also signaling via Akt and Erk in all cell lines. Immunoprecipitation revealed Src: ER complexes only in the parental T47D cells. In fulvestrant resistant cells, Src formed complexes with the Human Epidermal growth factor Receptor (HER)1 and HER2. Neither HER receptors nor ER were co-precipitated with Src in the tamoxifen resistant cell lines. Compared to treatment with dasatinib alone, combined treatment with dasatinib and fulvestrant had a stronger inhibitory effect on tamoxifen resistant cell growth, whereas dasatinib in combination with tamoxifen had no additive inhibitory effect on fulvestrant resistant growth. When performing immunohistochemical staining on 268 primary tumors from breast cancer patients who had received tamoxifen as first line endocrine treatment, we found that membrane expression of Src in the tumor cells was significant associated with reduced disease-free and overall survival. In conclusion, Src was identified as target for treatment of antiestrogen resistant T47D breast cancer cells. For tamoxifen resistant T47D cells, combined treatment with dasatinib and fulvestrant was superior to treatment with dasatinib alone. Src located at the membrane has potential as a new biomarker for reduced benefit of tamoxifen. PMID

  11. Tamoxifen induces regression of estradiol-induced mammary cancer in the ACI.COP-Ept2 rat model.

    Science.gov (United States)

    Ruhlen, Rachel L; Willbrand, Dana M; Besch-Williford, Cynthia L; Ma, Lixin; Shull, James D; Sauter, Edward R

    2009-10-01

    The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5-7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonance imaging, by 89%. Tumors expressed estrogen receptors (ER), progesterone receptor (PR), and Erbb2. ERalpha and PR were overexpressed in tumor compared to adjacent non-tumor mammary gland. Thus, this model is highly relevant to hormone responsive human breast cancers.

  12. FGFR2-Driven Signaling Counteracts Tamoxifen Effect on ERα-Positive Breast Cancer Cells

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    Lukasz Turczyk

    2017-10-01

    Full Text Available Signaling mediated by growth factors receptors has long been suggested as one of the key factors responsible for failure of endocrine treatment in breast cancer (BCa. Herein we present that in the presence of tamoxifen, FGFs (Fibroblast Growth Factors promote BCa cell growth with the strongest effect being produced by FGF7. FGFR2 was identified as a mediator of FGF7 action and the FGFR2-induced signaling was found to underlie cancer-associated fibroblasts-dependent resistance to tamoxifen. FGF7/FGFR2-triggered pathway was shown to induce ER phosphorylation, ubiquitination and subsequent ER proteasomal degradation which counteracted tamoxifen-promoted ER stabilization. We also identified activation of PI3K/AKT signaling targeting ER-Ser167 and regulation of Bcl-2 expression as a mediator of FGFR2-promoted resistance to tamoxifen. Analysis of tissue samples from patients with invasive ductal carcinoma revealed an inversed correlation between expression of FGFR2 and ER, thus supporting our in vitro data. These results unveil the complexity of ER regulation by FGFR2-mediated signaling likely to be associated with BCa resistance to endocrine therapy.

  13. Nontranscriptional activation of PI3K/Akt signaling mediates hypotensive effect following activation of estrogen receptor β in the rostral ventrolateral medulla of rats

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    Wu Kay LH

    2012-08-01

    Full Text Available Abstract Background Estrogen acts on the rostral ventrolateral medulla (RVLM, where sympathetic premotor neurons are located, to elicit vasodepressor effects via an estrogen receptor (ERβ-dependent mechanism. We investigated in the present study nontranscriptional mechanism on cardiovascular effects following activation of ERβ in the RVLM, and delineated the involvement of phosphatidylinositol 3-kinase (PI3K/serine/threonine kinase (Akt signaling pathway in the effects. Methods In male Sprague–Dawley rats maintained under propofol anesthesia, changes in arterial pressure, heart rate and sympathetic neurogenic vasomotor tone were examined after microinjection bilaterally into RVLM of 17β-estradiol (E2β or a selective ERα or ERβ agonist. Involvement of ER subtypes and PI3K/Akt signaling pathway in the induced cardiovascular effects were studied using pharmacological tools of antagonists or inhibitors, gene manipulation with antisense oligonucleotide (ASON or adenovirus-mediated gene transfection. Results Similar to E2β (1 pmol, microinjection of ERβ agonist, diarylpropionitrile (DPN, 1, 2 or 5 pmol, into bilateral RVLM evoked dose-dependent hypotension and reduction in sympathetic neurogenic vasomotor tone. These vasodepressive effects of DPN (2 pmol were inhibited by ERβ antagonist, R,R-tetrahydrochrysene (50 pmol, ASON against ERβ mRNA (250 pmol, PI3K inhibitor LY294002 (5 pmol, or Akt inhibitor (250 pmol, but not by ERα inhibitor, methyl-piperidino-pyrazole (1 nmol, or transcription inhibitor, actinomycin D (5 or 10 nmol. Gene transfer by microinjection into bilateral RVLM of adenovirus encoding phosphatase and tensin homologues deleted on chromosome 10 (5 × 108 pfu reversed the vasodepressive effects of DPN. Conclusions Our results indicate that vasodepressive effects following activation of ERβ in RVLM are mediated by nongenomic activation of PI3K/Akt signaling pathway. This study provides new insight in the

  14. The Wnt signalling pathway is upregulated in an in vitro model of acquired tamoxifen resistant breast cancer

    International Nuclear Information System (INIS)

    Loh, Yan Ni; Hedditch, Ellen L; Baker, Laura A; Jary, Eve; Ward, Robyn L; Ford, Caroline E

    2013-01-01

    Acquired resistance to Tamoxifen remains a critical problem in breast cancer patient treatment, yet the underlying causes of resistance have not been fully elucidated. Abberations in the Wnt signalling pathway have been linked to many human cancers, including breast cancer, and appear to be associated with more metastatic and aggressive types of cancer. Here, our aim was to investigate if this key pathway was involved in acquired Tamoxifen resistance, and could be targeted therapeutically. An in vitro model of acquired Tamoxifen resistance (named TamR) was generated by growing the estrogen receptor alpha (ER) positive MCF7 breast cancer cell line in increasing concentrations of Tamoxifen (up to 5 uM). Alterations in the Wnt signalling pathway and epithelial to mesenchymal transition (EMT) in response to Tamoxifen and treatment with the Wnt inhibitor, IWP-2 were measured via quantitative RT-PCR (qPCR) and TOP/FOP Wnt reporter assays. Resistance to Tamoxifen, and effects of IWP-2 treatment were determined by MTT proliferation assays. TamR cells exhibited increased Wnt signalling as measured via the TOP/FOP Wnt luciferase reporter assays. Genes associated with both the β-catenin dependent (AXIN2, MYC, CSNK1A1) and independent arms (ROR2, JUN), as well as general Wnt secretion (PORCN) of the Wnt signalling pathway were upregulated in the TamR cells compared to the parental MCF7 cell line. Treatment of the TamR cell line with human recombinant Wnt3a (rWnt3a) further increased the resistance of both MCF7 and TamR cells to the anti-proliferative effects of Tamoxifen treatment. TamR cells demonstrated increased expression of EMT markers (VIM, TWIST1, SNAI2) and decreased CDH1, which may contribute to their resistance to Tamoxifen. Treatment with the Wnt inhibitor, IWP-2 inhibited cell proliferation and markers of EMT. These data support the role of the Wnt signalling pathway in acquired resistance to Tamoxifen. Further research into the mechanism by which activated Wnt

  15. Anti-Inflammatory Effects of Tanshinone IIA on Atherosclerostic Vessels of Ovariectomized ApoE-/- Mice are Mediated by Estrogen Receptor Activation and Through the ERK Signaling Pathway

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    Xin Liu

    2015-03-01

    Full Text Available Aims: Estrogen plays a protective role in atherosclerosis. Our preliminary work demonstrated that the active conformation of Tanshinone IIA(TanIIA is similar to the 17ß-estradiol and it can bind to the estrogen receptor. Here, we hypothesized that Tanshinone IIA might have anti-inflammatory and anti-oxidative effects in atherosclerosis, mediated through estrogen receptor activation. Methods: Subjects for this study were 120 apoE-/- female mice and 20 C57/BL female mice. The apoE-/- mice were ovariectomized (OVX and the C57/BL mice were sham ovariectomized. The sham OVX mice were maintained on a normal diet (NOR group. The OVX apoE-/- mice were fed a high fat diet and randomly divided into 6 groups: Model (MOD group which was fed a high fat diet only, E2 group were given estrogen (E2 0.13mg/kg/d; E2+ICI group were given E2:0.13mg/kg/d and ICI182780:65mg/kg/m; TLD group (TanIIA low dose were given TanIIA: 30mg/kg/d; THD group (TanIIA high dose were given TanIIA:60mg/kg/d; and TLD+ICI group were given TanIIA 30mg/kg/d and ICI182780 65mg/kg/m. After three months of treatment, the aorta and the blood of the mice from each group was collected. The aorta were used for testing the lipid deposition by using hematoxylin and eosin(HE and oil red O staining and for testing the expression of p-ERK1/2 by Western blot. The blood was used for testing the serum cholesterol, superoxide dismutase (SOD, methane dicarboxylic aldehyde (MDA, nuclear factor kappa (NF-κB, soluble intercellular cell adhesion molecule-1 (sICAM-1, activating protein-1 (AP-1, E-selectin and 17ß-estradiol in serum. Results: Tanshinone IIA significantly reduced the lipid deposition in aorta, decreased the levels of total cholesterol (TC, triglyceride (TG, low density lipoprotein (LDL, very low density lipoprotein (VLDL, MDA, NF-κB, sICAM-1, AP-1, and E-selectin in serum but increased the levels of high density lipoprotein (HDL and SOD in serum. Tanshinone IIA also suppressed the

  16. Comprehensive assessment of cytochromes P450 and transporter genetics with endoxifen concentration during tamoxifen treatment.

    Science.gov (United States)

    Marcath, Lauren A; Deal, Allison M; Van Wieren, Emily; Danko, William; Walko, Christine M; Ibrahim, Joseph G; Weck, Karen E; Jones, David R; Desta, Zeruesenay; McLeod, Howard L; Carey, Lisa A; Irvin, William J; Hertz, Daniel L

    2017-11-01

    Tamoxifen bioactivation to endoxifen is mediated primarily by CYP2D6; however, considerable variability remains unexplained. Our aim was to perform a comprehensive assessment of the effect of genetic variation in tamoxifen-relevant enzymes and transporters on steady-state endoxifen concentrations. Comprehensive genotyping of CYP enzymes and transporters was performed using the iPLEX ADME PGx Pro Panel in 302 tamoxifen-treated breast cancer patients. Predicted activity phenotype for 19 enzymes and transporters were analyzed for univariate association with endoxifen concentration, and then adjusted for CYP2D6 and clinical covariates. In univariate analysis, higher activity of CYP2C8 (regression β=0.22, P=0.020) and CYP2C9 (β=0.20, P=0.04), lower body weight (β=-0.014, P<0.0001), and endoxifen measurement during winter (each β<-0.39, P=0.002) were associated with higher endoxifen concentrations. After adjustment for the CYP2D6 diplotype, weight, and season, CYP2C9 remained significantly associated with higher concentrations (P=0.02), but only increased the overall model R by 1.3%. Our results further support a minor contribution of CYP2C9 genetic variability toward steady-state endoxifen concentrations. Integration of clinician and genetic variables into individualized tamoxifen dosing algorithms would marginally improve their accuracy and potentially enhance tamoxifen treatment outcomes.

  17. Tumor specific HMG-CoA reductase expression in primary pre-menopausal breast cancer predicts response to tamoxifen

    LENUS (Irish Health Repository)

    Brennan, Donal J

    2011-01-31

    Abstract Introduction We previously reported an association between tumor-specific 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMG-CoAR) expression and a good prognosis in breast cancer. Here, the predictive value of HMG-CoAR expression in relation to tamoxifen response was examined. Methods HMG-CoAR protein and RNA expression was analyzed in a cell line model of tamoxifen resistance using western blotting and PCR. HMG-CoAR mRNA expression was examined in 155 tamoxifen-treated breast tumors obtained from a previously published gene expression study (Cohort I). HMG-CoAR protein expression was examined in 422 stage II premenopausal breast cancer patients, who had previously participated in a randomized control trial comparing 2 years of tamoxifen with no systemic adjuvant treatment (Cohort II). Kaplan-Meier analysis and Cox proportional hazards modeling were used to estimate the risk of recurrence-free survival (RFS) and the effect of HMG-CoAR expression on tamoxifen response. Results HMG-CoAR protein and RNA expression were decreased in tamoxifen-resistant MCF7-LCC9 cells compared with their tamoxifen-sensitive parental cell line. HMG-CoAR mRNA expression was decreased in tumors that recurred following tamoxifen treatment (P < 0.001) and was an independent predictor of RFS in Cohort I (hazard ratio = 0.63, P = 0.009). In Cohort II, adjuvant tamoxifen increased RFS in HMG-CoAR-positive tumors (P = 0.008). Multivariate Cox regression analysis demonstrated that HMG-CoAR was an independent predictor of improved RFS in Cohort II (hazard ratio = 0.67, P = 0.010), and subset analysis revealed that this was maintained in estrogen receptor (ER)-positive patients (hazard ratio = 0.65, P = 0.029). Multivariate interaction analysis demonstrated a difference in tamoxifen efficacy relative to HMG-CoAR expression (P = 0.05). Analysis of tamoxifen response revealed that patients with ER-positive\\/HMG-CoAR tumors had a significant response to tamoxifen (P = 0.010) as well as

  18. The Possible Effect Of Tamoxifen Vs Whole Body Irradiation Treatment On Thyroid Hormones in Female Rats Bearing Mammary Tumors Chemically Induced

    International Nuclear Information System (INIS)

    Abdelgawad, M.R.

    2012-01-01

    Breast cancer is the most common malignancy among women in most developed and developing regions of the world. In women, this drug has tissuespecific effects, acting as an estrogen antagonist on the breast, and as an estrogen agonist on bone, lipid metabolism (increasing high-density lipoprotein cholesterol and decreasing low-density lipoprotein cholesterol), and the endometrium. Thyroid hormones act on almost all organs throughout the body and regulate the basal metabolism of the organism. Thyroid hormone can also stimulate the proliferation in vitro of certain tumor cell lines. The aim of the present study is to evaluate the significant value of tamoxifen and/or irradiation treatment on thyroid hormones in breast cancer bearing female rats. Forty two female Sprague-Dawely rats randomly divided into seven groups and the effect of tamoxifen and post-irradiation was studied on breast cancer chemically induced. The results shows a T 4 and estradiol levels not T 3 were altered in different experimental groups. It could be concluded that irradiation-induced changes in the composition of the mammary microenvironment promote the expression of neoplastic potential by affecting both estradiol and thyroid hormones, and tamoxifen may alter the thyroid hormones. Irradiation and tamoxifen administration may have worth effects on T 4 and estradiol levels and it is recommended to further studies towards the bystander effect of radiation and tamoxifen on the tissue culture and molecular biology scale.

  19. The role of the expression of bcl-2, p53 gene in tamoxifen-induced apoptosis of breast cancer cells and its relationship with hormone receptor status

    International Nuclear Information System (INIS)

    Noh, Woo Chul; Ham, Yong Ho

    1998-01-01

    To investigate the relationship of bcl-2, p53, ER and tamoxifen-induced apoptosis of breast cancer cells, MCF-7 (ER+/bcl-2+/p53-) and MB MDA 468 (ER-/bcl-2-/p53+) cell line were cultured in estrogen-free condition. E2(10'-'9M) and tamoxifen (10'-'5M) were added to the media. The changes of bcl-2 and mutant p53 protein were checked by Western blot and apoptosis were measured by flowcytometry. In MCF-7 cells, we found that treatment with tamoxifen resulted in a decrease in bcl-2 protein level, but produced no change in mutant p53. In MB MDA 468 cell however, there were no changes of bcl-2 and mutant p53 protein level when E2 or tamoxifen were added. Apoptotic cells increased with time-dependent pattern when tamoxifen was added to MCF-7 cells. According to these result, ER+/blc-2+/mutant p53- cells, when treated with tamoxifen, were converted into bcl-2/mutant p53- cells which were more prone to apoptosis than bcl-2-/mutant p53+ cells. The paradoxical correlation of bcl-2 and ER which had been observed in clinical studies might be explained with this results and bcl-2 protein seems to be one of important factors that can predict the effect of hormone therapy. (author). 26 refs., 5 figs

  20. Viral Vector Mediated Over-Expression of Estrogen Receptor–α in Striatum Enhances the Estradiol-induced Motor Activity in Female Rats and Estradiol Modulated GABA Release

    Science.gov (United States)

    Schultz, Kristin N.; von Esenwein, Silke A.; Hu, Ming; Bennett, Amy L.; Kennedy, Robert T.; Musatov, Sergei; Toran-Allerand, C. Dominique; Kaplitt, Michael G.; Young, Larry J.; Becker, Jill B.

    2009-01-01

    Classical estrogen receptor signaling mechanisms involve estradiol binding to intracellular nuclear receptors (estrogen receptor-α (ERα) and estrogen receptor-β (ERβ)) to promote changes in protein expression. Estradiol can also exert effects within seconds to minutes, however, a timescale incongruent with genomic signaling. In the brain, estradiol rapidly potentiates stimulated dopamine release in the striatum of female rats and enhances spontaneous rotational behavior. Furthermore, estradiol rapidly attenuates the K+- evoked increase of GABA in dialysate. We hypothesize that these rapid effects of estradiol in the striatum are mediated by ERα located on the membrane of medium spiny GABAergic neurons. This experiment examined whether over-expression of ERα in the striatum would enhance the effect of estradiol on rotational behavior and the K+- evoked increase in GABA in dialysate. Ovariectomized female rats were tested for rotational behavior or underwent microdialysis experiments after unilateral intrastriatal injections of a recombinant adeno-associated virus (AAV) containing the human ERα cDNA (AAV.ERα) into the striatum; controls received either the same vector into areas outside the striatum or an AAV containing the human alkaline phosphatase gene into the striatum (AAV.ALP). Animals that received AAV.ERα in the striatum exhibited significantly greater estradiol-induced contralateral rotations compared to controls and exhibited behavioral sensitization of contralateral rotations induced by a low dose of amphetamine. ERα over-expression also enhanced the inhibitory effect of estradiol on K+- evoked GABA release suggesting that disinhibition of dopamine release from terminals in the striatum resulted in the enhanced rotational behavior. PMID:19211896

  1. Viral vector-mediated overexpression of estrogen receptor-alpha in striatum enhances the estradiol-induced motor activity in female rats and estradiol-modulated GABA release.

    Science.gov (United States)

    Schultz, Kristin N; von Esenwein, Silke A; Hu, Ming; Bennett, Amy L; Kennedy, Robert T; Musatov, Sergei; Toran-Allerand, C Dominique; Kaplitt, Michael G; Young, Larry J; Becker, Jill B

    2009-02-11

    Classical estrogen receptor-signaling mechanisms involve estradiol binding to intracellular nuclear receptors [estrogen receptor-alpha (ERalpha) and estrogen receptor-beta (ERbeta)] to promote changes in protein expression. Estradiol can also exert effects within seconds to minutes, however, a timescale incongruent with genomic signaling. In the brain, estradiol rapidly potentiates stimulated dopamine release in the striatum of female rats and enhances spontaneous rotational behavior. Furthermore, estradiol rapidly attenuates the K(+)-evoked increase of GABA in dialysate. We hypothesize that these rapid effects of estradiol in the striatum are mediated by ERalpha located on the membrane of medium spiny GABAergic neurons. This experiment examined whether overexpression of ERalpha in the striatum would enhance the effect of estradiol on rotational behavior and the K(+)-evoked increase in GABA in dialysate. Ovariectomized female rats were tested for rotational behavior or underwent microdialysis experiments after unilateral intrastriatal injections of a recombinant adeno-associated virus (AAV) containing the human ERalpha cDNA (AAV.ERalpha) into the striatum; controls received either the same vector into areas outside the striatum or an AAV containing the human alkaline phosphatase gene into the striatum (AAV.ALP). Animals that received AAV.ERalpha in the striatum exhibited significantly greater estradiol-induced contralateral rotations compared with controls and exhibited behavioral sensitization of contralateral rotations induced by a low-dose of amphetamine. ERalpha overexpression also enhanced the inhibitory effect of estradiol on K(+)-evoked GABA release suggesting that disinhibition of dopamine release from terminals in the striatum resulted in the enhanced rotational behavior.

  2. Quantitative proteomics and transcriptomics addressing the estrogen receptor subtype-mediated effects in T47D breast cancer cells exposed to the phytoestrogen genistein.

    Science.gov (United States)

    Sotoca, Ana M; Gelpke, Maarten D Sollewijn; Boeren, Sjef; Ström, Anders; Gustafsson, Jan-Åke; Murk, Albertinka J; Rietjens, Ivonne M C M; Vervoort, Jacques

    2011-01-01

    The present study addresses, by transcriptomics and quantitative stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics, the estrogen receptor α (ERα) and β (ERβ)-mediated effects on gene and protein expression in T47D breast cancer cells exposed to the phytoestrogen genistein. Using the T47D human breast cancer cell line with tetracycline-dependent ERβ expression (T47D-ERβ), the effect of a varying intracellular ERα/ERβ ratio on genistein-induced gene and protein expression was characterized. Results obtained reveal that in ERα-expressing T47D-ERβ cells with inhibited ERβ expression genistein induces transcriptomics and proteomics signatures pointing at rapid cell growth and migration by dynamic activation of cytoskeleton remodeling. The data reveal an interplay between integrins, focal adhesion kinase, CDC42, and actin cytoskeleton signaling cascades, occurring upon genistein treatment, in the T47D-ERβ breast cancer cells with low levels of ERα and no expression of ERβ. In addition, data from our study indicate that ERβ-mediated gene and protein expression counteracts ERα-mediated effects because in T47D-ERβ cells expressing ERβ and exposed to genistein transcriptomics and proteomics signatures pointing at a clear down-regulation of cell growth and induction of cell cycle arrest and apoptosis were demonstrated. These results suggest that ERβ decreases cell motility and metastatic potential as well as cell survival of the breast cancer cell line. It is concluded that the effects of genistein on proteomics and transcriptomics end points in the T47D-ERβ cell model are comparable with those reported previously for estradiol with the ultimate estrogenic effect being dependent on the relative affinity for both receptors and on the receptor phenotype (ERα/ERβ ratio) in the cells or tissue of interest.

  3. PD-1 Interaction with PD-L1 but not PD-L2 on B-cells Mediates Protective Effects of Estrogen against EAE.

    Science.gov (United States)

    Bodhankar, Sheetal; Galipeau, Danielle; Vandenbark, Arthur A; Offner, Halina

    2013-05-06

    Increased remissions in multiple sclerosis (MS) during late pregnancy may result from high levels of sex steroids such as estrogen and estriol. Estrogen (E2=17β-estradiol) protects against experimental autoimmune encephalomyelitis (EAE), but the cellular basis for E2-induced protection remains unclear. Treatment with relatively low doses of E2 can protect against clinical and histological signs of MOG- 35-55 induced EAE through mechanisms involving the PD-1 coinhibitory pathway and B-cells. The current study evaluated the contribution of PD-1 ligands, PD-L1 and PD-L2, on B-cells in E2-mediated protection against EAE in WT, PD-L1 -/- and PD-L2 -/- mice. Unlike PD-L2 -/- mice that were fully protected against EAE after E2 treatment, E2-implanted PD-L1 -/- mice were fully susceptible to EAE, with increased numbers of proliferating Th1/Th17 cells in the periphery and severe cellular infiltration and demyelination in the CNS. Moreover, transfer of B-cells from MOG-immunized PD-L1 -/- or PD-L2 -/- donors into E2-preconditioned B-cell deficient μMT -/- recipient mice revealed significantly reduced E2-mediated protection against EAE in recipients of PD-L1 -/- B-cells, but near-complete protection in recipients of PD-L2 -/- B-cells. We conclude that PD-1 interaction with PD-L1 but not PD-L2 on B-cells is crucial for E2-mediated protection in EAE and that strategies that enhance PD-1/PD-L1 interactions might potentiate E2 treatment effects in MS.

  4. E2F1-mediated transcriptional inhibition of the plasminogen activator inhibitor type 1 gene

    DEFF Research Database (Denmark)

    Koziczak, M; Müller, H; Helin, K

    2001-01-01

    -sensitive retinoblastoma protein (pRB), a shift to a permissive temperature induced PAI-1 mRNA expression. In U2OS cells stably expressing an E2F1-estrogen receptor chimeric protein that could be activated by tamoxifen, PAI-1 gene transcription was markedly reduced by tamoxifen even in the presence of cycloheximide...

  5. Ten Years of Tamoxifen Reduces Breast Cancer Recurrences, Improves Survival

    Science.gov (United States)

    ... of Breast & Gynecologic Cancers Breast Cancer Screening Research Ten Years of Tamoxifen Reduces Breast Cancer Recurrences, Improves ... a link to this page included, e.g., “Ten Years of Tamoxifen Reduces Breast Cancer Recurrences, Improves ...

  6. Effects of liarozole fumarate (R85246) in combination with tamoxifen on N-methyl-N-nitrosourea (MNU)-induced mammary carcinoma and uterus in the rat model

    International Nuclear Information System (INIS)

    Goss, Paul E; Strasser-Weippl, Kathrin; Qi, Shangle; Hu, Haiqing

    2007-01-01

    Liarozole fumarate (liarozole – R85246) is a novel compound with characteristics of both aromatase inhibitor (AI) and a retinoic acid metabolism blocking agent (RAMBA). Our objective was to determine the effects of liarozole alone or in combination with tamoxifen on the N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinoma model, as well as on the uterus in ovariectomized immature rats. (1) Tumor burden experiments: Animals bearing one or more tumors greater than 10 mm in diameter were treated for 56 consecutive days with 20 mg/kg or 80 mg/kg of liarozole by oral gavage, tamoxifen 100 μg/kg by subcutaneous injection, or a combination of liarozole and tamoxifen. At the end of the treatment period, total cumulative tumor volume as well as retinoic acid levels were measured. (2) Uterotrophic assay and proliferation experiments: 21-day-old ovariectomized (OVX) Sprague-Dawley rats were treated with 20 mg/kg or 80 mg/kg of liarozole by oral gavage, tamoxifen 1 mg/kg by subcutaneous injection, and combination of both for 4 consecutive days. At the end of the treatment period, uterine weight, epithelial lining cell height and indices of proliferation cell nuclear antigen (PCNA) were measured. The tumor burden experiments in rats bearing estrogen receptor (ER) positive mammary tumours showed that liarozole has a marked anti-tumour effect. In combination with tamoxifen, liarozole had neither an additive nor an antagonistic effect. However, liarozole markedly reduced the uterotrophic effects induced by tamoxifen. Liarozole's antitumor effects on ER positive mammary tumors and its protective effect on the uterus merit further studies to confirm its clinical value in combination with tamoxifen in ER positive postmenopausal breast cancer. Liarozole and other retinomimetics might also be suitable chemoprevention drugs in combination with tamoxifen because of their favorable toxicity profile

  7. Protection of cortical cells by equine estrogens against glutamate-induced excitotoxicity is mediated through a calcium independent mechanism

    Directory of Open Access Journals (Sweden)

    Perrella Joel

    2005-05-01

    Full Text Available Abstract Background High concentrations of glutamate can accumulate in the brain and may be involved in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease. This form of neurotoxicity involves changes in the regulation of cellular calcium (Ca2+ and generation of free radicals such as peroxynitrite (ONOO-. Estrogen may protect against glutamate-induced cell death by reducing the excitotoxic Ca2+ influx associated with glutamate excitotoxicity. In this study, the inhibition of N-methyl-D-aspartate (NMDA receptor and nitric oxide synthase (NOS along with the effect of 17β-estradiol (17β-E2 and a more potent antioxidant Δ8, 17β-estradiol (Δ8, 17β-E2 on cell viability and intracellular Ca2+ ([Ca2+]i, following treatment of rat cortical cells with glutamate, was investigated. Results Primary rat cortical cells were cultured for 7–12 days in Neurobasal medium containing B27 supplements. Addition of glutamate (200 μM decreased cell viability to 51.3 ± 0.7% compared to control. Treatment with the noncompetitive NMDAR antagonist, MK-801, and the NOS inhibitor, L-NAME, completely prevented cell death. Pretreatment (24 hrs with 17β-E2 and Δ8, 17β-E2 (0.01 to 10 μM significantly reduced cell death. 17β-E2 was more potent than Δ8, 17β-E2. Glutamate caused a rapid 2.5 fold increase in [Ca2+]i. Treatment with 0.001 to 10 μM MK-801 reduced the initial Ca2+ influx by 14–41% and increased cell viability significantly. Pretreatment with 17β-E2 and Δ8, 17β-E2 had no effect on Ca2+ influx but protected the cortical cells against glutamate-induced cell death. Conclusion Glutamate-induced cell death in cortical cultures can occur through NMDAR and NOS-linked mechanisms by increasing nitric oxide and ONOO-. Equine estrogens: 17β-E2 and Δ8, 17β-E2, significantly protected cortical cells against glutamate-induced excitotoxicity by a mechanism that appears to be independent of Ca2+ influx. To our knowledge, this is a first

  8. Adenosine monophosphate activated protein kinase (AMPK), a mediator of estradiol-induced apoptosis in long-term estrogen deprived breast cancer cells.

    Science.gov (United States)

    Chen, Haiyan; Wang, Ji-Ping; Santen, Richard J; Yue, Wei

    2015-06-01

    Estrogens stimulate growth of hormone-dependent breast cancer but paradoxically induce tumor regress under certain circumstances. We have shown that long-term estrogen deprivation (LTED) enhances the sensitivity of hormone dependent breast cancer cells to estradiol (E2) so that physiological concentrations of estradiol induce apoptosis in these cells. E2-induced apoptosis involve both intrinsic and extrinsic pathways but precise mechanisms remain unclear. We found that exposure of LTED MCF-7 cells to E2 activated AMP activated protein kinase (AMPK). In contrast, E2 inhibited AMPK activation in wild type MCF-7 cells where E2 prevents apoptosis. As a result of AMPK activation, the transcriptional activity of FoxO3, a downstream factor of AMPK, was up-regulated in E2 treatment of LTED. Increased activity of FoxO3 was demonstrated by up-regulation of three FoxO3 target genes, Bim, Fas ligand (FasL), and Gadd45α. Among them, Bim and FasL mediate intrinsic and extrinsic apoptosis respectively and Gadd45α causes cell cycle arrest at the G2/M phase. To further confirm the role of AMPK in apoptosis, we used AMPK activator AICAR in wild type MCF-7 cells and examined apoptosis, proliferation and expression of Bim, FasL, and Gadd45α. The effects of AICAR on these parameters recapitulated those observed in E2-treated LTED cells. Activation of AMPK by AICAR also increased expression of Bax in MCF-7 cells and its localization to mitochondria, which is a required process for apoptosis. These results reveal that AMPK is an important factor mediating E2-induced apoptosis in LTED cells, which is implicative of therapeutic potential for relapsing breast cancer after hormone therapy.

  9. Estrogen Injection

    Science.gov (United States)

    ... class of medications called hormones. It works by replacing estrogen that is normally produced by the body. ... your doctor about eating grapefruit and drinking grapefruit juice while using this medicine.

  10. Estrogen Test

    Science.gov (United States)

    ... and Iron-binding Capacity (TIBC, UIBC) Trichomonas Testing Triglycerides Troponin Tryptase Tumor Markers Uric Acid Urinalysis Urine ... in men and play a role in bone metabolism and growth in both sexes. Estrogen tests measure ...

  11. Flavonoids Induce the Synthesis and Secretion of Neurotrophic Factors in Cultured Rat Astrocytes: A Signaling Response Mediated by Estrogen Receptor

    Directory of Open Access Journals (Sweden)

    Sherry L. Xu

    2013-01-01

    Full Text Available Neurotrophic factors are playing vital roles in survival, growth, and function of neurons. Regulation of neurotrophic factors in the brain has been considered as one of the targets in developing drug or therapy against neuronal disorders. Flavonoids, a family of multifunctional natural compounds, are well known for their neuronal beneficial effects. Here, the effects of flavonoids on regulating neurotrophic factors were analyzed in cultured rat astrocytes. Astrocyte is a major secreting source of neurotrophic factors in the brain. Thirty-three flavonoids were screened in the cultures, and calycosin, isorhamnetin, luteolin, and genistein were identified to be highly active in inducing the synthesis and secretion of neurotrophic factors, including nerve growth factor (NGF, glial-derived neurotrophic factor (GDNF, and brain-derived neurotrophic factor (BDNF. The inductions were in time- and dose-dependent manners. In cultured astrocytes, the phosphorylation of estrogen receptor was triggered by application of flavonoids. The phosphorylation was blocked by an inhibitor of estrogen receptor, which in parallel reduced the flavonoid-induced expression of neurotrophic factors. The results proposed the role of flavonoids in protecting brain diseases, and therefore these flavonoids could be developed for health food supplement for patients suffering from neurodegenerative diseases.

  12. Association of tissue inhibitor of metalloproteinases-1 and Ki67 in estrogen receptor positive breast cancer

    DEFF Research Database (Denmark)

    Bjerre, Christina Annette; Knoop, Ann; Bjerre, Karsten

    2013-01-01

    The role of tissue inhibitor of metalloproteinases-1 (TIMP-1) in estrogen receptor (ER) positive breast cancer remains to be fully elucidated. We evaluated TIMP-1 as a prognostic marker in patients treated with adjuvant tamoxifen and investigated TIMP-1s association with Ki67 and ER/progesterone ....../progesterone receptor (PR)/human epidermal growth factor receptor 2 (HER2) profiles....

  13. Evaluation of Tamoxifen and metabolites by LC-MS/MS and HPLC Methods

    OpenAIRE

    Heath, D.D.; Flatt, S.W.; Wu, A.H.B.; Pruitt, M.A.; Rock, C.L.

    2014-01-01

    Epidemiological and laboratory evidence suggests that quantification of serum or plasma levels of tamoxifen and the metabolites of tamoxifen, 4-hydroxy-N-desmethyl-tamoxifen (endoxifen), Z-4-hydroxy-tamoxifen (4HT), N-desmethyl-tamoxifen (ND-tam) is a clinically useful tool in the assessment and monitoring of breast cancer status in patients taking adjuvant tamoxifen. A liquid chromatographic mass spectrometric method (LC-MS/MS) was used to measure the blood levels of tamoxifen and the metabo...

  14. “Iron-saturated” bovine lactoferrin improves the chemotherapeutic effects of tamoxifen in the treatment of basal-like breast cancer in mice

    International Nuclear Information System (INIS)

    Sun, Xueying; Jiang, Ruohan; Przepiorski, Aneta; Reddy, Shiva; Palmano, Kate P; Krissansen, Geoffrey W

    2012-01-01

    Tamoxifen is used in hormone therapy for estrogen-receptor (ER)-positive breast cancer, but also has chemopreventative effects against ER-negative breast cancers. This study sought to investigate whether oral iron-saturated bovine lactoferrin (Fe-Lf), a natural product which enhances chemotherapy, could improve the chemotherapeutic effects of tamoxifen in the treatment of ER-negative breast cancers. In a model of breast cancer prevention, female Balb/c mice treated with tamoxifen (5 mg/Kg) were fed an Fe-Lf supplemented diet (5 g/Kg diet) or the base diet. At week 2, 4T1 mammary carcinoma cells were injected into an inguinal mammary fat pad. In a model of breast cancer treatment, tamoxifen treatment was not started until two weeks following tumor cell injection. Tumor growth, metastasis, body weight, and levels of interleukin 18 (IL-18) and interferon γ (IFN-γ) were analyzed. Tamoxifen weakly (IC 50 ~ 8 μM) inhibited the proliferation of 4T1 cells at pharmacological concentrations in vitro. In the tumor prevention study, a Fe-Lf diet in combination with tamoxifen caused a 4 day delay in tumor formation, and significantly inhibited tumor growth and metastasis to the liver and lung by 48, 58, and 66% (all P < 0.001), respectively, compared to untreated controls. The combination therapy was significantly (all P < 0.05) more effective than the respective monotherapies. Oral Fe-Lf attenuated the loss of body weight caused by tamoxifen and cancer cachexia. It prevented tamoxifen-induced reductions in serum levels of IL-18 and IFN-γ, and intestinal cells expressing IL-18 and IFN-γ. It increased the levels of Lf in leukocytes residing in gut-associated lymphoid tissues. B, T and Natural killer (NK) cells containing high levels of Lf were identified in 4T1 tumors, suggesting they had migrated from the intestine. Similar effects of Fe-Lf and tamoxifen on tumor cell viability were seen in the treatment of established tumors. The results indicate that Fe-Lf is a potent

  15. Coffee prevents early events in tamoxifen-treated breast cancer patients and modulates hormone receptor status.

    Science.gov (United States)

    Simonsson, Maria; Söderlind, Viktoria; Henningson, Maria; Hjertberg, Maria; Rose, Carsten; Ingvar, Christian; Jernström, Helena

    2013-05-01

    Whether coffee modulates response to endocrine therapy in breast cancer patients is currently unknown. The CYP1A2 and CYP2C8 enzymes contribute to tamoxifen and caffeine metabolism. The purpose was to investigate the impact of coffee consumption on tumor characteristics and risk for early events in relation to breast cancer treatment and CYP1A2 and CYP2C8 genotypes. Questionnaires regarding lifestyle were completed preoperatively by 634 patients in southern Sweden. CYP1A2*1F and CYP2C8*3 were genotyped. Clinical data and tumor characteristics were obtained from patients' charts, population registries, and pathology reports. Coffee consumption was categorized as low (0-1 cups/day), moderate (2-4 cups/day), or high (5+ cups/day). The proportion of estrogen receptor negative (ER-) tumors increased with increasing coffee consumption (p trend = 0.042). Moderate to high consumption was associated with lower frequency of discordant receptor status (ER + PgR-) OR 0.38 (0.23-0.63) compared to low consumption. Median follow-up time was 4.92 (IQR 3.01-6.42) years. Tamoxifen-treated patients with ER+ tumors (n = 310) who consumed two or more cups/day had significantly decreased risk for early events compared to patients with low consumption, adjusted HR 0.40 (0.19-0.83). Low consumption combined with at least one CYP1A2*1F C-allele (n = 35) or CYP2C8*3 (n = 13) was associated with a high risk for early events in tamoxifen-treated patients compared to other tamoxifen-treated patients, adjusted HRs 3.49 (1.54-7.91) and 6.15 (2.46-15.36), respectively. Moderate to high coffee consumption was associated with significantly decreased risk for early events in tamoxifen-treated patients and modified hormone receptor status. If confirmed, new recommendations regarding coffee consumption during tamoxifen treatment may be warranted.

  16. Microencapsulation of tamoxifen: application to cotton fabric.

    Science.gov (United States)

    Ma, Zong-Hui; Yu, Deng-Guang; Branford-White, Christopher J; Nie, Hua-Li; Fan, Zai-Xia; Zhu, Li-Min

    2009-02-15

    Tamoxifen microcapsules and drug loaded medicated fabrics were investigated. The microcapsules were prepared using a complex coacervation procedure involving gelatin B and acacia gum. The morphology, particle size, drug loading capacity and in vitro release characteristics of the drug microcapsules were optimized for coating tamoxifen microcapsules onto the cotton fabrics. Infrared (IR) spectra and SEM were used to characterize the medicated fabrics and air permeability and laundering testing were undertaken to determine the efficiency and effectiveness of the system. Results showed that optimum condition for the microcapsules was at drug/polymer ratio 1:4, polymer concentration 3%, and rate of stirring 1000 rpm. In vitro release assays demonstrated that the tamoxifen was liberated over 10h after an initial bust rate period. SEM images illustrated that the tamoxifen microcapsules were spherical in shape and were also tightly fixed on to the cotton fabrics fast. These observations demonstrate that we have designed and fabricated a medicated system that potentially could be applied within a transdermal drug delivery system and so act in a system for the treatment of breast cancer.

  17. Uterine and placental expression of TRPV6 gene is regulated via progesterone receptor- or estrogen receptor-mediated pathways during pregnancy in rodents

    Directory of Open Access Journals (Sweden)

    Choi Kyung-Chul

    2009-05-01

    Full Text Available Abstract Transient receptor potential cation channel, subfamily V, member 6 (TRPV6 is an epithelial Ca2+ channel protein expressed in calcium absorbing organs. In the present study, we investigated the expression and regulation of uterine and placental TRPV6 during gestation in rodents. Uterine TRPV6 peaked at pregnancy day (P 0.5, P5.5 and, P13.5 and was detected in uterine epithelium and glands of rats, while placental TRPV6 mRNA levels increased in mid-gestation. Uterine and placental TRPV6 mRNA levels in rats appear to cyclically change during pregnancy, suggesting that TRPV6 may participate in the implantation process. In addition, uterine TRPV6 mRNA is only expressed in placenta-unattached areas of the uterus, and uterine TRPV6 immunoreactivity was observed in luminal and glandular epithelial cells. In the placenta, TRPV6 was detected in the labyrinth and spongy zone. These results may indicate that TRPV6 has at least two functions: implantation of the embryo and maintenance of pregnancy. To investigate the pathway(s mediating TRPV6 expression in rodents, anti-steroid hormone antagonists were injected prior to maximal TRPV6 expression. In rats, TRPV6 expression was reduced by RU486 (an anti-progesterone through progesterone receptors, and ICI 182,780 (an anti-estrogen blocked TRPV6 expression via estrogen receptors in mice. The juxtaposition of uterine and placental TRPV6 expressed in these tissues supports the notion that TRPV6 participates in transferring calcium ions between the maternal and fetal compartments. Taken together, TRPV6 gene may function as a key element in controlling calcium transport in the uterus between the embryo and the placenta during pregnancy.

  18. Estrogen-Related Receptor Alpha Confers Methotrexate Resistance via Attenuation of Reactive Oxygen Species Production and P53 Mediated Apoptosis in Osteosarcoma Cells

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2014-01-01

    Full Text Available Osteosarcoma (OS is a malignant tumor mainly occurring in children and adolescents. Methotrexate (MTX, a chemotherapy agent, is widely used in treating OS. However, treatment failures are common due to acquired chemoresistance, for which the underlying molecular mechanisms are still unclear. In this study, we report that overexpression of estrogen-related receptor alpha (ERRα, an orphan nuclear receptor, promoted cell survival and blocked MTX-induced cell death in U2OS cells. We showed that MTX induced ROS production in MTX-sensitive U2OS cells while ERRα effectively blocked the ROS production and ROS associated cell apoptosis. Our further studies demonstrated that ERRα suppressed ROS induction of tumor suppressor P53 and its target genes NOXA and XAF1 which are mediators of P53-dependent apoptosis. In conclusion, this study demonstrated that ERRα plays an important role in the development of MTX resistance through blocking MTX-induced ROS production and attenuating the activation of p53 mediated apoptosis signaling pathway, and points to ERRα as a novel target for improving osteosarcoma therapy.

  19. A Novel Mechanism of Estrogen Action in Breast Cancer Cells Mediated Through ER-FE65 Complex Formation

    Science.gov (United States)

    2013-03-01

    breast cancer cells mediated through ER-FE65 complex formation PRINCIPAL INVESTIGATOR: Wenlong Bai, Ph.D. CONTRACTING ORGANIZATION...breast cancer cells mediated through ER-FE65 complex formation 5b. GRANT NUMBER W81XWH-09-1-0574 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...above information, we proposed a novel function for Fe65 in breast cancer cells . We hypothesize that Fe65 functions as a dual adaptor for ERα and

  20. Tamoxifen counteracts estradiol induced effects on striatal and hypophyseal dopamine receptors

    International Nuclear Information System (INIS)

    Ferretti, C.; Blengio, M.; Ghi, P.; Racca, S.; Genazzani, E.; Portaleone, P.

    1988-01-01

    We investigated the ability of Tamoxifen (TAM), an antiestrogen drug, to counteract the modification induced by estrogens on dopamine (DA) receptors on striatum and on adenohypophysis of ovex female rats. Subacute treatment with 17β-estradiol (E 2 ) at both low (0.1 μg/kg) and high (20 μg/kg) doses confirmed its ability to increase the number of striatal 3 H-Spiperone ( 3 H-SPI) binding sites in a dose dependent manner. By contrast in the pituitary, only high doses of estrogen were effective in reducing the number of DA receptors. We treated ovex female rats for 15 days with TAM alone or associated with E 2 , to see if these estrogenic effects could be suppressed by an antiestrogenic drug. TAM did not affect the number of striatal DA receptors, but significantly increased the adenohypophy-seal DA binding sites, without varying their affinity. No changes were observed in pituitary and striatal DA receptor density, even when TAM was injected in association with estradiol. In conclusions: TAM is able to counteract the effects estrogens have on DA receptors. However there is some evidence that it could influence the pituitary DA systems independently of it antiestrogenic activity

  1. Tamoxifen counteracts estradiol induced effects on striatal and hypophyseal dopamine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, C.; Blengio, M.; Ghi, P.; Racca, S.; Genazzani, E.; Portaleone, P.

    1988-01-01

    We investigated the ability of Tamoxifen (TAM), an antiestrogen drug, to counteract the modification induced by estrogens on dopamine (DA) receptors on striatum and on adenohypophysis of ovex female rats. Subacute treatment with 17..beta..-estradiol (E/sub 2/) at both low (0.1 ..mu..g/kg) and high (20 ..mu..g/kg) doses confirmed its ability to increase the number of striatal /sup 3/H-Spiperone (/sup 3/H-SPI) binding sites in a dose dependent manner. By contrast in the pituitary, only high doses of estrogen were effective in reducing the number of DA receptors. We treated ovex female rats for 15 days with TAM alone or associated with E/sub 2/, to see if these estrogenic effects could be suppressed by an antiestrogenic drug. TAM did not affect the number of striatal DA receptors, but significantly increased the adenohypophy-seal DA binding sites, without varying their affinity. No changes were observed in pituitary and striatal DA receptor density, even when TAM was injected in association with estradiol. In conclusions: TAM is able to counteract the effects estrogens have on DA receptors. However there is some evidence that it could influence the pituitary DA systems independently of it antiestrogenic activity.

  2. Estrogen-, androgen- and aryl hydrocarbon receptor mediated activities in passive and composite samples from municipal waste and surface waters.

    Science.gov (United States)

    Jálová, V; Jarošová, B; Bláha, L; Giesy, J P; Ocelka, T; Grabic, R; Jurčíková, J; Vrana, B; Hilscherová, K

    2013-09-01

    Passive and composite sampling in combination with in vitro bioassays and identification and quantification of individual chemicals were applied to characterize pollution by compounds with several specific modes of action in urban area in the basin of two rivers, with 400,000 inhabitants and a variety of industrial activities. Two types of passive samplers, semipermeable membrane devices (SPMD) for hydrophobic contaminants and polar organic chemical integrative samplers (POCIS) for polar compounds such as pesticides and pharmaceuticals, were used to sample wastewater treatment plant (WWTP) influent and effluent as well as rivers upstream and downstream of the urban complex and the WWTP. Compounds with endocrine disruptive potency were detected in river water and WWTP influent and effluent. Year-round, monthly assessment of waste waters by bioassays documented estrogenic, androgenic and dioxin-like potency as well as cytotoxicity in influent waters of the WWTP and allowed characterization of seasonal variability of these biological potentials in waste waters. The WWTP effectively removed cytotoxic compounds, xenoestrogens and xenoandrogens. There was significant variability in treatment efficiency of dioxin-like potency. The study indicates that the WWTP, despite its up-to-date technology, can contribute endocrine disrupting compounds to the river. Riverine samples exhibited dioxin-like, antiestrogenic and antiandrogenic potencies. The study design enabled characterization of effects of the urban complex and the WWTP on the river. Concentrations of PAHs and contaminants and specific biological potencies sampled by POCIS decreased as a function of distance from the city. © 2013.

  3. Toosendanin Exerts an Anti-Cancer Effect in Glioblastoma by Inducing Estrogen Receptor β- and p53-Mediated Apoptosis

    Directory of Open Access Journals (Sweden)

    Liang Cao

    2016-11-01

    Full Text Available Glioblastoma (GBM is the most common primary brain tumor with median survival of approximately one year. This dismal poor prognosis is due to resistance to currently available chemotherapeutics; therefore, new cytotoxic agents are urgently needed. In the present study, we reported the cytotoxicity of toosendanin (TSN in the GBM U87 and C6 cell lines in vitro and in vivo. By using the MTT (3-(4,5-dimethyl-2-thiazolyl-2,5-diphenyl-2-H-tetrazolium bromide assay, flow cytometry analysis, and Western blot, we found that TSN inhibited U87 and C6 cell proliferation and induced apoptosis at a concentration as low as 10 nM. Administration of TSN also reduced tumor burden in a xenograft model of athymic nude mice. Pharmacological and molecular studies suggested that estrogen receptor β (ERβ and p53 were prominent targets for TSN. GBM cell apoptosis induced by TSN was a stepwise biological event involving the upregulation of ERβ and contextual activation of functional p53. Collectively, our study indicates, for the first time, that TSN is a candidate of novel anti-cancer drugs for GBM. Furthermore, ERβ and p53 could act as predictive biomarkers for the sensitivity of cancer to TSN.

  4. Expression profiles of estrogen-regulated microRNAs in breast cancer cells

    OpenAIRE

    Katchy, Anne; Williams, Cecilia

    2016-01-01

    Molecular signaling through both estrogen and microRNAs are critical for breast cancer development and growth. The activity of estrogen is mediated by transcription factors, the estrogen receptors. Here we describe a method for robust characterization of estrogen-regulated microRNA profiles. The method details how to prepare cells for optimal estrogen response, directions for estrogen treatment, RNA extraction, microRNA large-scale profiling and subsequent confirmations.

  5. The prolyl isomerase Pin1 acts synergistically with CDK2 to regulate the basal activity of estrogen receptor α in breast cancer.

    Directory of Open Access Journals (Sweden)

    Chiara Lucchetti

    Full Text Available In hormone receptor-positive breast cancers, most tumors in the early stages of development depend on the activity of the estrogen receptor and its ligand, estradiol. Anti-estrogens, such as tamoxifen, have been used as the first line of therapy for over three decades due to the fact that they elicit cell cycle arrest. Unfortunately, after an initial period, most cells become resistant to hormonal therapy. Peptidylprolyl isomerase 1 (Pin1, a protein overexpressed in many tumor types including breast, has been demonstrated to modulate ERalpha activity and is involved in resistance to hormonal therapy. Here we show a new mechanism through which CDK2 drives an ERalpha-Pin1 interaction under hormone- and growth factor-free conditions. The PI3K/AKT pathway is necessary to activate CDK2, which phosphorylates ERalphaSer294, and mediates the binding between Pin1 and ERalpha. Site-directed mutagenesis demonstrated that ERalphaSer294 is essential for Pin1-ERalpha interaction and modulates ERalpha phosphorylation on Ser118 and Ser167, dimerization and activity. These results open up new drug treatment opportunities for breast cancer patients who are resistant to anti-estrogen therapy.

  6. Inhibition of β-Catenin to Overcome Endocrine Resistance in Tamoxifen-Resistant Breast Cancer Cell Line.

    Science.gov (United States)

    Won, Hye Sung; Lee, Kyung Mee; Oh, Ju Eon; Nam, Eun Mi; Lee, Kyoung Eun

    2016-01-01

    The β-catenin signaling is important in cell growth and differentiation and is frequently dysregulated in various cancers. The most well-known mechanism of endocrine resistance is cross-talk between the estrogen receptor (ER) and other growth factor signaling, such as phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) signaling pathway. In the present study, we investigated whether β-catenin could be a potential target to overcome endocrine resistance in breast cancer. We established tamoxifen-resistant (TamR) cell line via long-term exposure of MCF-7 breast cancer cells to gradually increasing concentrations of tamoxifen. The levels of protein expression and mRNA transcripts were determined using western blot analysis and real-time quantitative PCR. The transcriptional activity of β-catenin was measured using luciferase activity assay. TamR cells showed a mesenchymal phenotype, and exhibited a relatively decreased expression of ER and increased expression of human epidermal growth factor receptor 2 and the epidermal growth factor receptor. We confirmed that the expression and transcriptional activity of β-catenin were increased in TamR cells compared with control cells. The expression and transcriptional activity of β-catenin were inhibited by β-catenin small-molecule inhibitor, ICG-001 or β-catenin siRNA. The viability of TamR cells, which showed no change after treatment with tamoxifen, was reduced by ICG-001 or β-catenin siRNA. The combination of ICG-001 and mTOR inhibitor, rapamycin, yielded an additive effect on the inhibition of viability in TamR cells. These results suggest that β-catenin plays a role in tamoxifen-resistant breast cancer, and the inhibition of β-catenin may be a potential target in tamoxifen-resistant breast cancer.

  7. Inhibition of β-Catenin to Overcome Endocrine Resistance in Tamoxifen-Resistant Breast Cancer Cell Line.

    Directory of Open Access Journals (Sweden)

    Hye Sung Won

    Full Text Available The β-catenin signaling is important in cell growth and differentiation and is frequently dysregulated in various cancers. The most well-known mechanism of endocrine resistance is cross-talk between the estrogen receptor (ER and other growth factor signaling, such as phosphatidylinositol-3-kinase (PI3K/Akt and the mammalian target of rapamycin (mTOR signaling pathway. In the present study, we investigated whether β-catenin could be a potential target to overcome endocrine resistance in breast cancer.We established tamoxifen-resistant (TamR cell line via long-term exposure of MCF-7 breast cancer cells to gradually increasing concentrations of tamoxifen. The levels of protein expression and mRNA transcripts were determined using western blot analysis and real-time quantitative PCR. The transcriptional activity of β-catenin was measured using luciferase activity assay.TamR cells showed a mesenchymal phenotype, and exhibited a relatively decreased expression of ER and increased expression of human epidermal growth factor receptor 2 and the epidermal growth factor receptor. We confirmed that the expression and transcriptional activity of β-catenin were increased in TamR cells compared with control cells. The expression and transcriptional activity of β-catenin were inhibited by β-catenin small-molecule inhibitor, ICG-001 or β-catenin siRNA. The viability of TamR cells, which showed no change after treatment with tamoxifen, was reduced by ICG-001 or β-catenin siRNA. The combination of ICG-001 and mTOR inhibitor, rapamycin, yielded an additive effect on the inhibition of viability in TamR cells.These results suggest that β-catenin plays a role in tamoxifen-resistant breast cancer, and the inhibition of β-catenin may be a potential target in tamoxifen-resistant breast cancer.

  8. Tamoxifen from Failed Contraceptive Pill to Best-Selling Breast Cancer Medicine: A Case-Study in Pharmaceutical Innovation.

    Science.gov (United States)

    Quirke, Viviane M

    2017-01-01

    Today, tamoxifen is one of the world's best-selling hormonal breast cancer drugs. However, it was not always so. Compound ICI 46,474 (as it was first known) was synthesized in 1962 within a project to develop a contraceptive pill in the pharmaceutical laboratories of ICI (now part of AstraZeneca). Although designed to act as an anti-estrogen, the compound stimulated, rather than suppressed ovulation in women. This, and the fact that it could not be patented in the USA, its largest potential market, meant that ICI nearly stopped the project. It was saved partly because the team's leader, Arthur Walpole, threatened to resign, and pressed on with another project: to develop tamoxifen as a treatment for breast cancer. Even then, its market appeared small, because at first it was mainly used as a palliative treatment for advanced breast cancer. An important turning point in tamoxifen's journey from orphan drug to best-selling medicine occurred in the 1980s, when clinical trials showed that it was also useful as an adjuvant to surgery and chemotherapy in the early stages of the disease. Later, trials demonstrated that it could prevent its occurrence or re-occurrence in women at high risk of breast cancer. Thus, it became the first preventive for any cancer, helping to establish the broader principles of chemoprevention, and extending the market for tamoxifen and similar drugs further still. Using tamoxifen as a case study, this paper discusses the limits of the rational approach to drug design, the role of human actors, and the series of feedback loops between bench and bedside that underpins pharmaceutical innovation. The paper also highlights the complex evaluation and management of risk that are involved in all therapies, but more especially perhaps in life-threatening and emotion-laden diseases like cancer.

  9. New steroidal aromatase inhibitors: Suppression of estrogen-dependent breast cancer cell proliferation and induction of cell death

    Directory of Open Access Journals (Sweden)

    Roleira Fernanda MF

    2008-07-01

    Full Text Available Abstract Background Aromatase, the cytochrome P-450 enzyme (CYP19 responsible for estrogen biosynthesis, is an important target for the treatment of estrogen-dependent breast cancer. In fact, the use of synthetic aromatase inhibitors (AI, which induce suppression of estrogen synthesis, has shown to be an effective alternative to the classical tamoxifen for the treatment of postmenopausal patients with ER-positive breast cancer. New AIs obtained, in our laboratory, by modification of the A and D-rings of the natural substrate of aromatase, compounds 3a and 4a, showed previously to efficiently suppress aromatase activity in placental microsomes. In the present study we have investigated the effects of these compounds on cell proliferation, cell cycle progression and induction of cell death using the estrogen-dependent human breast cancer cell line stably transfected with the aromatase gene, MCF-7 aro cells. Results The new steroids inhibit hormone-dependent proliferation of MCF-7aro cells in a time and dose-dependent manner, causing cell cycle arrest in G0/G1 phase and inducing cell death with features of apoptosis and autophagic cell death. Conclusion Our in vitro studies showed that the two steroidal AIs, 3a and 4a, are potent inhibitors of breast cancer cell proliferation. Moreover, it was also shown that the antiproliferative effects of these two steroids on MCF-7aro cells are mediated by disrupting cell cycle progression, through cell cycle arrest in G0/G1 phase and induction of cell death, being the dominant mechanism autophagic cell death. Our results are important for the elucidation of the cellular effects of steroidal AIs on breast cancer.

  10. Placental Kisspeptins Differentially Modulate Vital Parameters of Estrogen Receptor-Positive and -Negative Breast Cancer Cells

    Science.gov (United States)

    Rasoulzadeh, Zahra; Ghods, Roya; Kazemi, Tohid; Mirzadegan, Ebrahim; Ghaffari-Tabrizi-Wizsy, Nassim; Rezania, Simin; Kazemnejad, Somaieh; Arefi, Soheila; Ghasemi, Jamileh; Vafaei, Sedigheh; Mahmoudi, Ahmad-Reza; Zarnani, Amir-Hassan

    2016-01-01

    Kisspeptins (KPs) are major regulators of trophoblast and cancer invasion. Thus far, limited and conflicting data are available on KP-mediated modulation of breast cancer (BC) metastasis; mostly based on synthetic KP-10, the most active fragment of KP. Here, we report for the first time comprehensive functional effects of term placental KPs on proliferation, adhesion, Matrigel invasion, motility, MMP activity and pro-inflammatory cytokine production in MDA-MB-231 (estrogen receptor-negative) and MCF-7 (estrogen receptor-positive). KPs were expressed at high level by term placental syncytiotrophoblasts and released in soluble form. Placental explant conditioned medium containing KPs (CM) significantly reduced proliferation of both cell types compared to CM without (w/o) KP (CM-w/o KP) in a dose- and time-dependent manner. In MDA-MB-231 cells, placental KPs significantly reduced adhesive properties, while increased MMP9 and MMP2 activity and stimulated invasion. Increased invasiveness of MDA-MB-231 cells after CM treatment was inhibited by KP receptor antagonist, P-234. CM significantly reduced motility of MCF-7 cells at all time points (2–30 hr), while it stimulated motility of MDA-MB-231 cells. These effects were reversed by P-234. Co-treatment with selective ER modulators, Tamoxifen and Raloxifene, inhibited the effect of CM on motility of MCF-7 cells. The level of IL-6 in supernatant of MCF-7 cells treated with CM was higher compared to those treated with CM-w/o KP. Both cell types produced more IL-8 after treatment with CM compared to those treated with CM-w/o KP. Taken together, our observations suggest that placental KPs differentially modulate vital parameters of estrogen receptor-positive and -negative BC cells possibly through modulation of pro-inflammatory cytokine production. PMID:27101408

  11. Tamoxifen therapy in breast cancer control worldwide.

    OpenAIRE

    Love, R. R.; Koroltchouk, V.

    1993-01-01

    In most developed and many developing countries, breast cancer is the most frequent cancer and the leading cause of cancer death among women. At least 50% of all breast cancer patients worldwide would survive longer, however, if public awareness about and early detection of the condition were increased and greater use were made of efficient treatment of proven value. With early-stage, localized breast cancer, local treatment combined with adjuvant hormonal therapy with tamoxifen, a synthetic ...

  12. Estradiol-mediated internalisation of the non-activated estrogen receptor from the goat uterine plasma membrane: identification of the proteins involved.

    Science.gov (United States)

    Sreeja, S; Thampan, Raghava Varman

    2004-04-01

    An indirect approach has been made to study the molecular details associated with the estradiol-induced internalisation of the non-activated estrogen receptor (naER) from the goat uterine plasma membrane. The internalisation of naER appears to be an energy dependent process. Exposure of the plasma membrane to estradiol results in the activation of a Mg2+ dependent ATPase associated with the membrane fraction. Presence of quercetin in the medium prevented the activation of the Mg2+ ATPase as well as the dissociation of naER from the plasma membrane. Using isolated plasma membrane preparations it has been possible to identify the proteins which interact with naER during various stages of its internalisation. The main proteins identified are: (1) a 58 kDa protein, p58, which apparently recognizes the nuclear localization signals on the naER and transports it to the nucleus: (2) hsp70: (3) hsp90, the functional roles of which remain unknown at this stage; (4) a 50 kDa protein associated with the clathrin coated vesicles, presumed to be involved in recognizing the tyrosine based internalisation signals on the naER; (5) actin which mediates the plasma membrane-to-nucleus movement of the naER-p58 complex.

  13. Estrogenicity of food-associated estrogenic compounds in the fetuses of female transgenic mice upon oral and IP maternal exposure

    NARCIS (Netherlands)

    Veld, ter M.G.R.; Zawadzka, E.; Rietjens, I.M.C.M.; Murk, A.J.

    2009-01-01

    The present study investigated to what extent seven food-associated in vitro estrogenic compounds can induce estrogenic effects in the fetuses of pregnant female mice with an estrogen receptor (ER)-mediated luciferase (luc) reporter gene system. The luc-induction was determined either 8 h after

  14. Tumor suppressor ING4 inhibits estrogen receptor activity in breast cancer cells

    Directory of Open Access Journals (Sweden)

    Keenen MM

    2016-11-01

    Full Text Available Madeline M Keenen,1 Suwon Kim1,2 1Department of Basic Medical Sciences, University of Arizona College of Medicine – Phoenix, Phoenix, AZ, 2Division of Cancer and Cell Biology, Translational Genomics Research Institute, Phoenix, AZ, USA Abstract: Resistance to antiestrogen therapy remains a significant problem in breast cancer. Low expression of inhibitor of growth 4 (ING4 in primary tumors has been correlated with increased rates of recurrence in estrogen receptor-positive (ER+ breast cancer patients, suggesting a role for ING4 in ER signaling. This study provides evidence that ING4 inhibits ER activity. ING4 overexpression increased the sensitivity of T47D and MCF7 ER+ breast cancer cells to hormone deprivation. ING4 attenuated maximal estrogen-dependent cell growth without affecting the dose–response of estrogen. These results indicated that ING4 functions as a noncompetitive inhibitor of estrogen signaling and may inhibit estrogen-independent ER activity. Supportive of this, treatment with fulvestrant but not tamoxifen rendered T47D cells sensitive to hormone deprivation as did ING4 overexpression. ING4 did not affect nuclear ERα protein expression, but repressed selective ER-target gene transcription. Taken together, these results demonstrated that ING4 inhibited estrogen-independent ER activity, suggesting that ING4-low breast tumors recur faster due to estrogen-independent ER activity that renders tamoxifen less effective. This study puts forth fulvestrant as a proposed therapy choice for patients with ING4-low ER+ breast tumors. Keywords: tamoxifen resistance, transcription repression, PDZK1, TFF1, estrogen independent ERa, fulvestrant  

  15. Antiestrogenic activity of flavnoid phytochemicals mediated via c-Jun N-terminal protein kinase pathway. Cell-type specific regulation of estrogen receptor alpha

    Science.gov (United States)

    Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling in...

  16. Triclocarban mediates induction of xenobiotic metabolism through activation of the constitutive androstane receptor and the estrogen receptor alpha.

    Directory of Open Access Journals (Sweden)

    Mei-Fei Yueh

    Full Text Available Triclocarban (3,4,4'-trichlorocarbanilide, TCC is used as a broad-based antimicrobial agent that is commonly added to personal hygiene products. Because of its extensive use in the health care industry and resistance to degradation in sewage treatment processes, TCC has become a significant waste product that is found in numerous environmental compartments where humans and wildlife can be exposed. While TCC has been linked to a range of health and environmental effects, few studies have been conducted linking exposure to TCC and induction of xenobiotic metabolism through regulation by environmental sensors such as the nuclear xenobiotic receptors (XenoRs. To identify the ability of TCC to activate xenobiotic sensors, we monitored XenoR activities in response to TCC treatment using luciferase-based reporter assays. Among the XenoRs in the reporter screening assay, TCC promotes both constitutive androstane receptor (CAR and estrogen receptor alpha (ERα activities. TCC treatment to hUGT1 mice resulted in induction of the UGT1A genes in liver. This induction was dependent upon the constitutive active/androstane receptor (CAR because no induction occurred in hUGT1Car(-/- mice. Induction of the UGT1A genes by TCC corresponded with induction of Cyp2b10, another CAR target gene. TCC was demonstrated to be a phenobarbital-like activator of CAR in receptor-based assays. While it has been suggested that TCC be classified as an endocrine disruptor, it activates ERα leading to induction of Cyp1b1 in female ovaries as well as in promoter activity. Activation of ERα by TCC in receptor-based assays also promotes induction of human CYP2B6. These observations demonstrate that TCC activates nuclear xenobiotic receptors CAR and ERα both in vivo and in vitro and might have the potential to alter normal physiological homeostasis. Activation of these xenobiotic-sensing receptors amplifies gene expression profiles that might represent a mechanistic base for

  17. Triclocarban Mediates Induction of Xenobiotic Metabolism through Activation of the Constitutive Androstane Receptor and the Estrogen Receptor Alpha

    Science.gov (United States)

    Yueh, Mei-Fei; Li, Tao; Evans, Ronald M.; Hammock, Bruce; Tukey, Robert H.

    2012-01-01

    Triclocarban (3,4,4′-trichlorocarbanilide, TCC) is used as a broad-based antimicrobial agent that is commonly added to personal hygiene products. Because of its extensive use in the health care industry and resistance to degradation in sewage treatment processes, TCC has become a significant waste product that is found in numerous environmental compartments where humans and wildlife can be exposed. While TCC has been linked to a range of health and environmental effects, few studies have been conducted linking exposure to TCC and induction of xenobiotic metabolism through regulation by environmental sensors such as the nuclear xenobiotic receptors (XenoRs). To identify the ability of TCC to activate xenobiotic sensors, we monitored XenoR activities in response to TCC treatment using luciferase-based reporter assays. Among the XenoRs in the reporter screening assay, TCC promotes both constitutive androstane receptor (CAR) and estrogen receptor alpha (ERα) activities. TCC treatment to hUGT1 mice resulted in induction of the UGT1A genes in liver. This induction was dependent upon the constitutive active/androstane receptor (CAR) because no induction occurred in hUGT1Car−/− mice. Induction of the UGT1A genes by TCC corresponded with induction of Cyp2b10, another CAR target gene. TCC was demonstrated to be a phenobarbital-like activator of CAR in receptor-based assays. While it has been suggested that TCC be classified as an endocrine disruptor, it activates ERα leading to induction of Cyp1b1 in female ovaries as well as in promoter activity. Activation of ERα by TCC in receptor-based assays also promotes induction of human CYP2B6. These observations demonstrate that TCC activates nuclear xenobiotic receptors CAR and ERα both in vivo and in vitro and might have the potential to alter normal physiological homeostasis. Activation of these xenobiotic-sensing receptors amplifies gene expression profiles that might represent a mechanistic base for potential human

  18. Intratumoral estrogen production and actions in luminal A type invasive lobular and ductal carcinomas.

    Science.gov (United States)

    Takagi, Mayu; Miki, Yasuhiro; Miyashita, Minoru; Hata, Shuko; Yoda, Tomomi; Hirakawa, Hisashi; Sagara, Yasuaki; Rai, Yoshiaki; Ohi, Yasuyo; Tamaki, Kentaro; Ishida, Takanori; Suzuki, Takashi; Ouchi, Noriaki; Sasano, Hironobu

    2016-02-01

    The great majority of invasive lobular carcinoma (ILC) is estrogen-dependent luminal A type carcinoma but the details of estrogen actions and its intratumoral metabolism have not been well studied compared to invasive ductal carcinoma (IDC). We first immunolocalized estrogen-related enzymes including estrogen sulfotransferase (EST), estrogen sulfatase (STS), 17β-hydroxysteroid dehydrogenase (HSD) 1/2, and aromatase. We then evaluated the tissue concentrations of estrogens in ILC and IDC and subsequently estrogen-responsive gene profiles in these tumors in order to explore the possible differences and/or similarity of intratumoral estrogen environment of these two breast cancer subtypes. The status of STS and 17βHSD1 was significantly lower in ILCs than IDCs (p = 0.022 and p < 0.0001), but that of EST and 17βHSD2 vice versa (p < 0.0001 and p = 0.0106). In ILCs, tissue concentrations of estrone and estradiol were lower than those in IDCs (p = 0.0709 and 0.069). In addition, the great majority of estrogen response genes tended to be lower in ILCs. Among those genes above, FOXP1 was significantly higher in ILCs than in IDCs (p = 0.002). FOXP1 expression was reported to be significantly higher in relapse-free IDC patients treated with tamoxifen. Therefore, tamoxifen may be considered an option of endocrine therapy for luminal A type ILC patients. This is the first study to demonstrate the detailed and comprehensive status of intratumoral production and metabolism of estrogens and the status of estrogen response genes in luminal A-like ILC with comparison to those in luminal A-like IDCs.

  19. Pierre Robin sequence associated with first trimester fetal tamoxifen exposure.

    Science.gov (United States)

    Berger, Joel C; Clericuzio, Carol L

    2008-08-15

    Tamoxifen is a nonsteroidal antiestrogen used as the current adjuvant endocrine treatment of choice for premenopausal women treated for breast cancer and its potential for causing fetal harm during pregnancy remains inconclusive. While the evidence of tamoxifen's effects on humans in utero is minimal, animal studies have shown evidence of teratogenicity, hence the FDA's class D categorization of the drug. In 1994 Cullins et al. published a case report entitled "Goldenhar's Syndrome Associated with Tamoxifen Given to the Mother During Gestation." At the time of publication, the authors noted that the manufacturer of tamoxifen knew of two cases associated with tamoxifen administration which resulted in congenital craniofacial defects. Cullins' case of Goldenhar syndrome is also a craniofacial disorder and thus represented the third such case. We report on the fourth case of a tamoxifen-associated craniofacial anomaly. The mother became pregnant while undergoing tamoxifen therapy for breast cancer. A child with severe micrognathia and cleft palate was born. It is noteworthy that the two patterns of craniofacial malformations in tamoxifen exposed infants--Goldenhar syndrome in Cullins' et al. case and Pierre Robin sequence reported here--have also both been observed in isotretinoin exposed infants. While a larger spectrum of anomalies is characteristic of retinoic acid embryopathy, the specific craniofacial anomalies include facial asymmetry, microtia, micrognatha and U-shaped cleft of the secondary palate, that is, malformations seen in the two tamoxifen exposed infants. Therefore, it is conceivable that these two agents could produce comparable embryotoxic effects if they function in a like way during embryogenesis. While the majority of tamoxifen exposed infants are normal, the ascertainment of teratogenic effects from tamoxifen will best be determined by data from teratogen registries. Copyright 2008 Wiley-Liss, Inc.

  20. Estrogen and Bazedoxifene

    Science.gov (United States)

    ... medications called estrogen agonist–antagonists. Estrogen works by replacing estrogen that is normally produced by the body. ... eat large amounts of grapefruit or drink grapefruit juice while taking this medication.

  1. Tamoxifen Pharmacovigilance: Implications for Safe Use in the Future.

    Science.gov (United States)

    Antimisiaris, Demetra; Bae, Ki-Hwan Gabriel; Morton, Laura; Gully, Zahara

    2017-09-01

    To survey the status of current tamoxifen pharmacovigilance documentation reflecting tamoxifen use in an academic outpatient multispecialty practice in older adults. This data will help provide information to develop improved pharmacovigilance for a growing cohort of older adult users. The data will be utilized by an interdisciplinary team developing new methods of identifying factors for individualized pharmacovigilance in older adults. Retrospective chart review to gather descriptive and quantitative data on tamoxifen pharmacovigilance. Multi-specialty clinic. Ninety-three patients 60 years of age and older. Quantitative report of tamoxifen monitoring as well as descriptive analysis of individual cases. We found 19 cases of serious adverse events possibly related to tamoxifen (thrombi, uterine malignancies). There were 15 cases with no documentation of pharmacovigilance. All cases had incomplete pharmacovigilance documented. There were two cases of hypercalcemia. There was one case of tamoxifen discontinuation resulting from muscle pain and with chronic muscle pain complaints while receiving tamoxifen. We observed a correlation in older age or high comorbidity burden patients and adverse events patients. Some studies direct the important pharmacovigilance toward prevention of thrombi, uterine malignancies, and hypercalcemia; however, it is not easy to identify recommendations for frequency or focus of monitoring to prevent adverse events for individual older adults based on existing recommendations. The data collected and presented in this study serve to heighten awareness of tamoxifen pharmacovigilance and as a starting point for the application of machine learning techniques and modeling to identify high-risk patients and individualized pharmacovigilance recommendations.

  2. Inhibition of Aerobic Glycolysis Represses Akt/mTOR/HIF-1α Axis and Restores Tamoxifen Sensitivity in Antiestrogen-Resistant Breast Cancer Cells.

    Science.gov (United States)

    Woo, Yu Mi; Shin, Yubin; Lee, Eun Ji; Lee, Sunyoung; Jeong, Seung Hun; Kong, Hyun Kyung; Park, Eun Young; Kim, Hyoung Kyu; Han, Jin; Chang, Minsun; Park, Jong-Hoon

    2015-01-01

    Tamoxifen resistance is often observed in the majority of estrogen receptor-positive breast cancers and it remains as a serious clinical problem in breast cancer management. Increased aerobic glycolysis has been proposed as one of the mechanisms for acquired resistance to chemotherapeutic agents in breast cancer cells such as adriamycin. Herein, we report that the glycolysis rates in LCC2 and LCC9--tamoxifen-resistant human breast cancer cell lines derived from MCF7--are higher than those in MCF7S, which is the parent MCF7 subline. Inhibition of key glycolytic enzyme such as hexokinase-2 resulted in cell growth retardation at higher degree in LCC2 and LCC9 than that in MCF7S. This implies that increased aerobic glycolysis even under O2-rich conditions, a phenomenon known as the Warburg effect, is closely associated with tamoxifen resistance. We found that HIF-1α is activated via an Akt/mTOR signaling pathway in LCC2 and LCC9 cells without hypoxic condition. Importantly, specific inhibition of hexokinase-2 suppressed the activity of Akt/mTOR/HIF-1α axis in LCC2 and LCC9 cells. In addition, the phosphorylated AMPK which is a negative regulator of mTOR was decreased in LCC2 and LCC9 cells compared to MCF7S. Interestingly, either the inhibition of mTOR activity or increase in AMPK activity induced a reduction in lactate accumulation and cell survival in the LCC2 and LCC9 cells. Taken together, our data provide evidence that development of tamoxifen resistance may be driven by HIF-1α hyperactivation via modulation of Akt/mTOR and/or AMPK signaling pathways. Therefore, we suggest that the HIF-1α hyperactivation is a critical marker of increased aerobic glycolysis in accordance with tamoxifen resistance and thus restoration of aerobic glycolysis may be novel therapeutic target for treatment of tamoxifen-resistant breast cancer.

  3. Estradiol-induced regression in T47D:A18/PKCalpha tumors requires the estrogen receptor and interaction with the extracellular matrix.

    Science.gov (United States)

    Zhang, Yiyun; Zhao, Huiping; Asztalos, Szilard; Chisamore, Michael; Sitabkhan, Yasmin; Tonetti, Debra A

    2009-04-01

    Several breast cancer tumor models respond to estradiol (E(2)) by undergoing apoptosis, a phenomenon known to occur in clinical breast cancer. Before the application of tamoxifen as an endocrine therapy, high-dose E(2) or diethystilbesterol treatment was successfully used, albeit with unfavorable side effects. It is now recognized that such an approach may be a potential endocrine therapy option. We have explored the mechanism of E(2)-induced tumor regression in our T47D:A18/PKCalpha tumor model that exhibits autonomous growth, tamoxifen resistance, and E(2)-induced tumor regression. Fulvestrant, a selective estrogen receptor (ER) down-regulator, prevents T47D:A18/PKCalpha E(2)-induced tumor growth inhibition and regression when given before or after tumor establishment, respectively. Interestingly, E(2)-induced growth inhibition is only observed in vivo or when cells are grown in Matrigel but not in two-dimensional tissue culture, suggesting the requirement of the extracellular matrix. Tumor regression is accompanied by increased expression of the proapoptotic FasL/FasL ligand proteins and down-regulation of the prosurvival Akt pathway. Inhibition of colony formation in Matrigel by E(2) is accompanied by increased expression of FasL and short hairpin RNA knockdown partially reverses colony formation inhibition. Classic estrogen-responsive element-regulated transcription of pS2, PR, transforming growth factor-alpha, C3, and cathepsin D is independent of the inhibitory effects of E(2). A membrane-impermeable E(2)-BSA conjugate is capable of mediating growth inhibition, suggesting the involvement of a plasma membrane ER. We conclude that E(2)-induced T47D:A18/PKCalpha tumor regression requires participation of ER-alpha, the extracellular matrix, FasL/FasL ligand, and Akt pathways, allowing the opportunity to explore new predictive markers and therapeutic targets.

  4. Effects of tamoxifen on the sex determination gene and the activation of sex reversal in the developing gonad of mice.

    Science.gov (United States)

    Yu, Mingxi; Wang, Jingyun; Liu, Wei; Qin, Junwen; Zhou, Quan; Wang, Yongan; Huang, Huihui; Chen, Wenli; Ma, Chao

    2014-07-03

    Tamoxifen, as well as most endocrine-disrupting chemicals, affects the reproductive system and sexual development, but little is known about its disruption of the molecular pathways regulating mammalian sex determination. In fetal mice, the expression levels and pattern of key genes involved in controlling sexually dimorphic balance were analyzed both in vivo and in vitro by using whole-mount in situ hybridization and quantitative-PCR. Developmental tamoxifen exposure induced abnormal up-regulation of the testis differentiation marker Pdfgra in Leydig cells and of Sox9 and Fgf9 in Sertoli cells in XX gonad. Immunohistochemistry analysis confirmed the over-expression of SOX9 protein. Accordingly, the ovary development marker Foxl2 was depressed at both the mRNA and protein levels. The increase in testosterone and the reduction in 17β-estradiol and progesterone were observed by using the in vitro assay with organotypic cultures. Taken together, results indicated that tamoxifen induced the ectopic expression of well-established sex-specific genes during the critical developmental period, thus resulting in abnormal testicular development in the XX gonad of mammals. This study facilitates a better understanding of the molecular mechanisms of antiestrogens and possibly of compounds that interrupt estrogen signaling by other modes of action, and the association with the pathogenesis of human sexual developmental disorders. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Black cohosh (Cimicifuga racemosa) in tamoxifen-treated breast cancer patients with climacteric complaints - a prospective observational study.

    Science.gov (United States)

    Rostock, Matthias; Fischer, Julia; Mumm, Andreas; Stammwitz, Ute; Saller, Reinhard; Bartsch, Hans Helge

    2011-10-01

    The antihormonal therapy of breast cancer patients with the antiestrogen tamoxifen often induces or aggravates menopausal complaints. As estrogen substitution is contraindicated, herbal alternatives, e.g. extracts of black cohosh are often used. A prospective observational study was carried out in 50 breast cancer patients with tamoxifen treatment. All patients had had surgery, most of them had undergone radiation therapy (87%) and approximately 50% had received chemotherapy. Every patient was treated with an isopropanolic extract of black cohosh (1-4 tablets, 2.5 mg) for 6 months. Patients recorded their complaints before therapy and after 1, 3, and 6 months of therapy using the menopause rating scale (MRS II). The reduction of the total MRS II score under black cohosh treatment from 17.6 to 13.6 was statistically significant. Hot flashes, sweating, sleep problems, and anxiety improved, whereas urogenital and musculoskeletal complaints did not change. In all, 22 patients reported adverse events, none of which were linked with the study medication; 90% reported the tolerability of the black cohosh extract as very good or good. Black cohosh extract seems to be a reasonable treatment approach in tamoxifen treated breast cancer patients with predominantly psychovegetative symptoms.

  6. One year of adjuvant tamoxifen compared with chemotherapy and tamoxifen in postmenopausal patients with stage II breast cancer

    DEFF Research Database (Denmark)

    Ejlertsen, Bent; Jensen, Maj-Britt; Elversang, Johanna

    2013-01-01

    We report the long-term results of a randomised trial comparing tamoxifen with tamoxifen plus cyclophosphamide, methotrexate and fluorouracil (CMF) in postmenopausal high-risk breast cancer patients. In addition, we analyse the prognostic and predictive value of centrally assessed subtypes....

  7. Tualang Honey Promotes Apoptotic Cell Death Induced by Tamoxifen in Breast Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Nik Soriani Yaacob

    2013-01-01

    Full Text Available Tualang honey (TH is rich in flavonoids and phenolic acids and has significant anticancer activity against breast cancer cells comparable to the effect of tamoxifen (TAM, in vitro. The current study evaluated the effects of TH when used in combination with TAM on MCF-7 and MDA-MB-231 cells. We observed that TH promoted the anticancer activity of TAM in both the estrogen receptor-(ER-responsive and ER-nonresponsive human breast cancer cell lines. Flow cytometric analyses indicated accelerated apoptosis especially in MDA-MB-231 cells and with the involvement of caspase-3/7, -8 and -9 activation as shown by fluorescence microscopy. Depolarization of the mitochondrial membrane was also increased in both cell lines when TH was used in combination with TAM compared to TAM treatment alone. TH may therefore be a potential adjuvant to be used with TAM for reducing the dose of TAM, hence, reducing TAM-induced adverse effects.

  8. Global characterization of signalling networks associated with tamoxifen resistance in breast cancer

    DEFF Research Database (Denmark)

    Browne, Brigid C.; Hochgräfe, Falko; Wu, Jianmin

    2013-01-01

    Acquired resistance to the anti‐estrogen tamoxifen remains a significant challenge in breast cancer management. In this study, we used an integrative approach to characterize global protein expression and tyrosine phosphorylation events in tamoxifen‐resistant MCF7 breast cancer cells (Tam......R cells. Phosphorylation of the tyrosine kinase Yes and expression of the actin‐binding protein myristoylated alanine‐rich C‐kinase substrate (MARCKS) were increased two‐ and eightfold in TamR cells respectively, and these proteins were selected for further analysis. Knockdown of either protein in Tam...... into the molecular alterations associated with the tamoxifen‐resistant phenotype, and identify MARCKS as a potential biomarker of therapeutic responsiveness that may assist in stratification of patients for optimal therapy....

  9. ER-α36, a novel variant of ER-α, mediates estrogen-stimulated proliferation of endometrial carcinoma cells via the PKCδ/ERK pathway.

    Directory of Open Access Journals (Sweden)

    Jing-Shan Tong

    2010-11-01

    Full Text Available Recently, a variant of ER-α, ER-α36 was identified and cloned. ER-α36 lacks intrinsic transcription activity and mainly mediates non-genomic estrogen signaling. The purpose of this study was to investigate the function and the underlying mechanisms of ER-α36 in growth regulation of endometrial Ishikawa cancer cells.The cellular localization of ER-α36 and ER-α66 were determined by immunofluorescence in the Ishikawa cells. Ishikawa endometrial cancer control cells transfected with an empty expression vector, Ishikawa cells with shRNA knockdown of ER-α36 (Ishikawa/RNAiER36 and Ishikawa cells with shRNA knockdown of ER-α66 (Ishikawa/RNAiER66 were treated with E2 and E2-conjugated to bovine serum albumin (E2-BSA, membrane impermeable in the absence and presence of different kinase inhibitors HBDDE, bisindolylmaleimide, rottlerin, H89 and U0126. The phosphorylation levels of signaling molecules and cyclin D1/cdk4 expression were examined with Western blot analysis and cell growth was monitored with the MTT assay.Immunofluorescence staining of Ishikawa cells demonstrated that ER-α36 was expressed mainly on the plasma membrane and in the cytoplasm, while ER-α66 was predominantly localized in the cell nucleus. Both E2 and E2-BSA rapidly activated PKCδ not PKCα in Ishikawa cells, which could be abrogated by ER-α36 shRNA expression. E2-and E2-BSA-induced ERK phosphorylation required ER-α36 and PKCδ. However, only E2 was able to induce Camp-dependent protein kinase A (PKA phosphorylation. Furthermore, E2 enhances cyclin D1/cdk4 expression via ER-α36.E2 activates the PKCδ/ERK pathway and enhances cyclin D1/cdk4 expression via the membrane-initiated signaling pathways mediated by ER-α36, suggesting a possible involvement of ER-α36 in E2-dependent growth-promoting effects in endometrial cancer cells.

  10. Sex bias in experimental immune-mediated, drug-induced liver injury in BALB/c mice: suggested roles for Tregs, estrogen, and IL-6.

    Directory of Open Access Journals (Sweden)

    Joonhee Cho

    Full Text Available Immune-mediated, drug-induced liver injury (DILI triggered by drug haptens is more prevalent in women than in men. However, mechanisms responsible for this sex bias are not clear. Immune regulation by CD4+CD25+FoxP3+ regulatory T-cells (Tregs and 17β-estradiol is crucial in the pathogenesis of sex bias in cancer and autoimmunity. Therefore, we investigated their role in a mouse model of immune-mediated DILI.To model DILI, we immunized BALB/c, BALB/cBy, IL-6-deficient, and castrated BALB/c mice with trifluoroacetyl chloride-haptenated liver proteins. We then measured degree of hepatitis, cytokines, antibodies, and Treg and splenocyte function.BALB/c females developed more severe hepatitis (p<0.01 and produced more pro-inflammatory hepatic cytokines and antibodies (p<0.05 than did males. Castrated males developed more severe hepatitis than did intact males (p<0.001 and females (p<0.05. Splenocytes cultured from female mice exhibited fewer Tregs (p<0.01 and higher IL-1β (p<0.01 and IL-6 (p<0.05 than did those from males. However, Treg function did not differ by sex, as evidenced by absence of sex bias in programmed death receptor-1 and responses to IL-6, anti-IL-10, anti-CD3, and anti-CD28. Diminished hepatitis in IL-6-deficient, anti-IL-6 receptor α-treated, ovariectomized, or male mice; undetectable IL-6 levels in splenocyte supernatants from ovariectomized and male mice; elevated splenic IL-6 and serum estrogen levels in castrated male mice, and IL-6 induction by 17β-estradiol in splenocytes from naïve female mice (p<0.05 suggested that 17β-estradiol may enhance sex bias through IL-6 induction, which subsequently discourages Treg survival. Treg transfer from naïve female mice to those with DILI reduced hepatitis severity and hepatic IL-6.17β-estradiol and IL-6 may act synergistically to promote sex bias in experimental DILI by reducing Tregs. Modulating Treg numbers may provide a therapeutic approach to DILI.

  11. MCF7/LCC9: an antiestrogen-resistant MCF-7 variant in which acquired resistance to the steroidal antiestrogen ICI 182,780 confers an early cross-resistance to the nonsteroidal antiestrogen tamoxifen

    DEFF Research Database (Denmark)

    Brünner, N; Boysen, B; Jirus, S

    1997-01-01

    Acquired resistance to antiestrogens is a major problem in the clinical management of initially endocrine responsive metastatic breast cancer. We have shown previously that estrogen-independent and -responsive MCF7/LCC1 human breast cancer cells selected for resistance to the triphenylethylene...... tamoxifen produce a variant (MCF7/LCC2) that retains sensitivity to the steroidal antiestrogen ICI 182,780 (N. Brunner et al., Cancer Res., 53: 3229-3232, 1993). We have now applied stepwise selections in vitro from 10 pM to 1 microM ICI 182,780 against MCF7/LCC1 and obtained a stable ICI 182,780-resistant...... variant designated MCF7/LCC9. In contrast to 4-hydroxytamoxifen-selected MCF7/LCC2 cells, MCF7/LCC9 cells exhibit full cross-resistance to tamoxifen, despite never having been exposed to this drug. Significantly, tamoxifen cross-resistance arose early in the selection, appearing following selection...

  12. Estrogen receptor testing and 10-year mortality from breast cancer: A model for determining testing strategy

    Directory of Open Access Journals (Sweden)

    Christopher Naugler

    2012-01-01

    Full Text Available Background: The use of adjuvant tamoxifen therapy in the treatment of estrogen receptor (ER expressing breast carcinomas represents a major advance in personalized cancer treatment. Because there is no benefit (and indeed there is increased morbidity and mortality associated with the use of tamoxifen therapy in ER-negative breast cancer, its use is restricted to women with ER expressing cancers. However, correctly classifying cancers as ER positive or negative has been challenging given the high reported false negative test rates for ER expression in surgical specimens. In this paper I model practice recommendations using published information from clinical trials to address the question of whether there is a false negative test rate above which it is more efficacious to forgo ER testing and instead treat all patients with tamoxifen regardless of ER test results. Methods: I used data from randomized clinical trials to model two different hypothetical treatment strategies: (1 the current strategy of treating only ER positive women with tamoxifen and (2 an alternative strategy where all women are treated with tamoxifen regardless of ER test results. The variables used in the model are literature-derived survival rates of the different combinations of ER positivity and treatment with tamoxifen, varying true ER positivity rates and varying false negative ER testing rates. The outcome variable was hypothetical 10-year survival. Results: The model predicted that there will be a range of true ER rates and false negative test rates above which it would be more efficacious to treat all women with breast cancer with tamoxifen and forgo ER testing. This situation occurred with high true positive ER rates and false negative ER test rates in the range of 20-30%. Conclusions: It is hoped that this model will provide an example of the potential importance of diagnostic error on clinical outcomes and furthermore will give an example of how the effect of that

  13. Mammographic changes in breast cancer patients treated with tamoxifen

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Keun; Oh, Ki Keun; Kim, Tae Hoon; Lee, Hy De [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-09-01

    To evaluate the efficacy of tamoxifen, as shown by mammographic changes. We studied the mammograms of 20 breast cancer patients treated with tamoxifen(20mg/day) and 20 patients treated with tamoxifen(20mg/day) in combination with chemothrapy. Control groups consisted of 20 breast cancer patients treated with chemotherapy and 20 healthy women;the patterns of age distribution and menstrual cycle among these participants were similar to these of the study groups. Two radiologists determined parenchymal changes as seen on follow-up mammogram, of the contralateral breast in patients with breast cancer, and of the left breast in healthy women. Follow-up mammogram showed decreased breast parenchyma in 75% of patients treated with tamoxifen, and in 70% of patients treated with tamoxifen and chemotherapy. Mammographic changes were not noted in 85% of patients treated with chemotherapy and in 90% of healthy women. On follow-up mammogram, breast parenchyma was seen to have been decreased by tamoxifen, used to prevent the recurrence of breast cancer and for its antiproliferative effect. Mammography might be a suitable method for determining the effect of tamoxifen.=20.

  14. Diacylglycerol kinase α mediates 17-β-estradiol-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line through the G protein-coupled estrogen receptor GPR30.

    Science.gov (United States)

    Filigheddu, Nicoletta; Sampietro, Sara; Chianale, Federica; Porporato, Paolo E; Gaggianesi, Miriam; Gregnanin, Ilaria; Rainero, Elena; Ferrara, Michele; Perego, Beatrice; Riboni, Francesca; Baldanzi, Gianluca; Graziani, Andrea; Surico, Nicola

    2011-12-01

    Increased levels of endogenous and/or exogenous estrogens are one of the well known risk factors of endometrial cancer. Diacylglycerol kinases (DGKs) are a family of enzymes which phosphorylate diacylglycerol (DAG) to produce phosphatidic acid (PA), thus turning off and on DAG-mediated and PA-mediated signaling pathways, respectively. DGK α activity is stimulated by growth factors and oncogenes and is required for chemotactic, proliferative, and angiogenic signaling in vitro. Herein, using either specific siRNAs or the pharmacological inhibitor R59949, we demonstrate that DGK α activity is required for 17-β-estradiol (E2)-induced proliferation, motility, and anchorage-independent growth of Hec-1A endometrial cancer cell line. Impairment of DGK α activity also influences basal cell proliferation and growth in soft agar of Hec-1A, while it has no effects on basal cell motility. Moreover, we show that DGK α activity induced by E2, as well as its observed effects, are mediated by the G protein-coupled estrogen receptor GPR30 (GPER). These findings suggest that DGK α may be a potential target in endometrial cancer therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Crosstalk between Wnt/β-catenin and estrogen receptor signaling synergistically promotes osteogenic differentiation of mesenchymal progenitor cells.

    Directory of Open Access Journals (Sweden)

    Yanhong Gao

    Full Text Available Osteogenic differentiation from mesenchymal progenitor cells (MPCs are initiated and regulated by a cascade of signaling events. Either Wnt/β-catenin or estrogen signaling pathway has been shown to play an important role in regulating skeletal development and maintaining adult tissue homeostasis. Here, we investigate the potential crosstalk and synergy of these two signaling pathways in regulating osteogenic differentiation of MPCs. We find that the activation of estrogen receptor (ER signaling by estradiol (E2 or exogenously expressed ERα in MPCs synergistically enhances Wnt3A-induced early and late osteogenic markers, as well as matrix mineralization. The E2 or ERα-mediated synergy can be effectively blocked by ERα antagonist tamoxifen. E2 stimulation can enhance endochondral ossification of Wnt3A-transduced mouse fetal limb explants. Furthermore, exogenously expressed ERα significantly enhances the maturity and mineralization of Wnt3A-induced subcutaneous and intramuscular ectopic bone formation. Mechanistically, we demonstrate that E2 does not exert any detectable effect on β-catenin/Tcf reporter activity. However, ERα expression is up-regulated within the first 48h in AdWnt3A-transduced MPCs, whereas ERβ expression is significantly inhibited within 24h. Moreover, the key enzyme for the biosynthesis of estrogens aromatase is modulated by Wnt3A in a biphasic manner, up-regulated at 24h but reduced after 48h. Our results demonstrate that, while ER signaling acts synergistically with Wnt3A in promoting osteogenic differentiation, Wnt3A may crosstalk with ER signaling by up-regulating ERα expression and down-regulating ERβ expression in MPCs. Thus, the signaling crosstalk and synergy between these two pathways should be further explored as a potential therapeutic approach to combating bone and skeletal disorders, such as fracture healing and osteoporosis.

  16. A New Therapeutic Paradigm for Breast Cancer Exploiting Low Dose Estrogen-Induce Apoptosis

    Science.gov (United States)

    2007-09-01

    Research with Selective Oestrogen Receptor Modulators to treat and prevent breast cancer. German Journal of Obstetrics and Gynecology. Georg Thieme...created a dilemma : if estrogen was essential to maintain bone density and could possi- bly protect women from coronary heart disease, how could women at...68 ) illustrates the dilemma for health care man- agement posed by the price of treatment. The authors concluded that tamoxifen-pricing

  17. Effects of estrogen on the vascular system

    Directory of Open Access Journals (Sweden)

    R.C. Tostes

    2003-09-01

    Full Text Available The cardiovascular protective actions of estrogen are partially mediated by a direct effect on the vessel wall. Estrogen is active both on vascular smooth muscle and endothelial cells where functionally competent estrogen receptors have been identified. Estrogen administration promotes vasodilation in humans and in experimental animals, in part by stimulating prostacyclin and nitric oxide synthesis, as well as by decreasing the production of vasoconstrictor agents such as cyclooxygenase-derived products, reactive oxygen species, angiotensin II, and endothelin-1. In vitro, estrogen exerts a direct inhibitory effect on smooth muscle by activating potassium efflux and by inhibiting calcium influx. In addition, estrogen inhibits vascular smooth muscle cell proliferation. In vivo, 17ß-estradiol prevents neointimal thickening after balloon injury and also ameliorates the lesions occurring in atherosclerotic conditions. As is the case for other steroids, the effect of estrogen on the vessel wall has a rapid non-genomic component involving membrane phenomena, such as alteration of membrane ionic permeability and activation of membrane-bound enzymes, as well as the classical genomic effect involving estrogen receptor activation and gene expression.

  18. Interplay between estrogen receptor and AKT in estradiol-induced alternative splicing.

    Science.gov (United States)

    Bhat-Nakshatri, Poornima; Song, Eun-Kyung; Collins, Nikail R; Uversky, Vladimir N; Dunker, A Keith; O'Malley, Bert W; Geistlinger, Tim R; Carroll, Jason S; Brown, Myles; Nakshatri, Harikrishna

    2013-06-11

    Alternative splicing is critical for generating complex proteomes in response to extracellular signals. Nuclear receptors including estrogen receptor alpha (ERα) and their ligands promote alternative splicing. The endogenous targets of ERα:estradiol (E2)-mediated alternative splicing and the influence of extracellular kinases that phosphorylate ERα on E2-induced splicing are unknown. MCF-7 and its anti-estrogen derivatives were used for the majority of the assays. CD44 mini gene was used to measure the effect of E2 and AKT on alternative splicing. ExonHit array analysis was performed to identify E2 and AKT-regulated endogenous alternatively spliced apoptosis-related genes. Quantitative reverse transcription polymerase chain reaction was performed to verify alternative splicing. ERα binding to alternatively spliced genes was verified by chromatin immunoprecipitation assay. Bromodeoxyuridine incorporation-ELISA and Annexin V labeling assays were done to measure cell proliferation and apoptosis, respectively. We identified the targets of E2-induced alternative splicing and deconstructed some of the mechanisms surrounding E2-induced splicing by combining splice array with ERα cistrome and gene expression array. E2-induced alternatively spliced genes fall into at least two subgroups: coupled to E2-regulated transcription and ERα binding to the gene without an effect on rate of transcription. Further, AKT, which phosphorylates both ERα and splicing factors, influenced ERα:E2 dependent splicing in a gene-specific manner. Genes that are alternatively spliced include FAS/CD95, FGFR2, and AXIN-1. E2 increased the expression of FGFR2 C1 isoform but reduced C3 isoform at mRNA level. E2-induced alternative splicing of FAS and FGFR2 in MCF-7 cells correlated with resistance to FAS activation-induced apoptosis and response to keratinocyte growth factor (KGF), respectively. Resistance of MCF-7 breast cancer cells to the anti-estrogen tamoxifen was associated with ER

  19. Enhanced expression of G-protein coupled estrogen receptor (GPER/GPR30) in lung cancer

    International Nuclear Information System (INIS)

    Jala, Venkatakrishna Rao; Radde, Brandie N; Haribabu, Bodduluri; Klinge, Carolyn M

    2012-01-01

    G-protein-coupled estrogen receptor (GPER/GPR30) was reported to bind 17β-estradiol (E 2 ), tamoxifen, and ICI 182,780 (fulvestrant) and promotes activation of epidermal growth factor receptor (EGFR)-mediated signaling in breast, endometrial and thyroid cancer cells. Although lung adenocarcinomas express estrogen receptors α and β (ERα and ERβ), the expression of GPER in lung cancer has not been investigated. The purpose of this study was to examine the expression of GPER in lung cancer. The expression patterns of GPER in various lung cancer lines and lung tumors were investigated using standard quantitative real time PCR (at mRNA levels), Western blot and immunohistochemistry (IHC) methods (at protein levels). The expression of GPER was scored and the pairwise comparisons (cancer vs adjacent tissues as well as cancer vs normal lung tissues) were performed. Analysis by real-time PCR and Western blotting revealed a significantly higher expression of GPER at both mRNA and protein levels in human non small cell lung cancer cell (NSCLC) lines relative to immortalized normal lung bronchial epithelial cells (HBECs). The virally immortalized human small airway epithelial cell line HPL1D showed higher expression than HBECs and similar expression to NSCLC cells. Immunohistochemical analysis of tissue sections of murine lung adenomas as well as human lung adenocarcinomas, squamous cell carcinomas and non-small cell lung carcinomas showed consistently higher expression of GPER in the tumor relative to the surrounding non-tumor tissue. The results from this study demonstrate increased GPER expression in lung cancer cells and tumors compared to normal lung. Further evaluation of the function and regulation of GPER will be necessary to determine if GPER is a marker of lung cancer progression

  20. The advantage of letrozole over tamoxifen in the BIG 1-98 trial is consistent in younger postmenopausal women and in those with chemotherapy-induced menopause

    DEFF Research Database (Denmark)

    Chirgwin, Jacquie; Sun, Zhuoxin; Smith, Ian

    2012-01-01

    subclinical ovarian estrogen production), and those with chemotherapy-induced menopause who may experience return of ovarian function. In these situations tamoxifen may be preferable to an aromatase inhibitor. Among 4,922 patients allocated to the monotherapy arms (5 years of letrozole or tamoxifen......) in the BIG 1-98 trial we identified two relevant subpopulations: patients with potential residual ovarian function, defined as having natural menopause, treated without adjuvant or neoadjuvant chemotherapy and age ≤ 55 years (n = 641); and those with chemotherapy-induced menopause (n = 105). Neither...... of the subpopulations examined showed treatment effects differing from the trial population as a whole (interaction P values are 0.23 and 0.62, respectively). Indeed, both among the 641 patients aged ≤ 55 years with natural menopause and no chemotherapy (HR 0.77 [0.51, 1.16]) and among the 105 patients...

  1. Estrogen, Estrogen Receptor and Lung Cancer

    Directory of Open Access Journals (Sweden)

    Li-Han Hsu

    2017-08-01

    Full Text Available Estrogen has been postulated as a contributor for lung cancer development and progression. We reviewed the current knowledge about the expression and prognostic implications of the estrogen receptors (ER in lung cancer, the effect and signaling pathway of estrogen on lung cancer, the hormone replacement therapy and lung cancer risk and survival, the mechanistic relationship between the ER and the epidermal growth factor receptor (EGFR, and the relevant clinical trials combining the ER antagonist and the EGFR antagonist, to investigate the role of estrogen in lung cancer. Estrogen and its receptor have the potential to become a prognosticator and a therapeutic target in lung cancer. On the other hand, tobacco smoking aggravates the effect of estrogen and endocrine disruptive chemicals from the environment targeting ER may well contribute to the lung carcinogenesis. They have gradually become important issues in the course of preventive medicine.

  2. Evidence that estrogen receptors play a limited role in mediating enhanced recovery of bile flow in female rats in the acute phase of liver ischemia reperfusion injury

    NARCIS (Netherlands)

    de Vries, Heleen A. H.; Ponds, Fraukje A. M.; Nieuwenhuijs, Vincent B.; Morphett, Arthur; Padbury, Robert T. A.; Barritt, Greg J.

    2013-01-01

    Introduction. Female patients exhibit better survival and less hepatic damage from ischemia reperfusion (IR) injury following surgery. However, the effects of sex and estrogens on liver function in the acute phase of IR are not well understood. Objective. The aim was to investigate this question.

  3. Tamoxifen for women at high risk of breast cancer

    OpenAIRE

    Nazarali, Safia A; Narod, Steven A

    2014-01-01

    Safia A Nazarali, Steven A Narod Women's College Research Institute, Women's College Hospital, and The University of Toronto, Toronto, Ontario, Canada Abstract: Tamoxifen has been used as a treatment for women who have been diagnosed with breast cancer for roughly four decades and has been approved as chemoprevention for over ten years. Although tamoxifen has been proven to be beneficial in preventing breast cancer in high-risk women, its use has not been widely embraced. To ...

  4. Early estrogen-induced metabolic changes and their inhibition by actinomycin D and cycloheximide in human breast cancer cells: sup 31 P and sup 13 C NMR studies

    Energy Technology Data Exchange (ETDEWEB)

    Neeman, M.; Degani, H. (Weizmann Institute of Science, Rehovot (Israel))

    1989-07-01

    Metabolic changes following estrogen stimulation and the inhibition of these changes in the presence of actinomycin D and cycloheximide were monitored continuously in perfused human breast cancer T47D clone 11 cells with {sup 31}P and {sup 13}C NMR techniques. The experiments were performed by estrogen rescue of tamoxifen-treated cells. Immediately after perfusion with estrogen-containing medium, a continuous enhancement in the rates of glucose consumption, lactate production by glycolysis, and glutamate synthesis by the Krebs cycle occurred with a persistent 2-fold increase at 4 hr. Pretreatment with either actinomycin D or cycloheximide, at concentrations known to inhibit mRNA and protein synthesis, respectively, and simultaneous treatment with estrogen and each inhibitor prevented the estrogen-induced changes in glucose metabolism. This suggested that the observed estrogen stimulation required synthesis of mRNA and protein. These inhibitors also modulated several metabolic activities that were not related to estrogen stimulation. The observed changes in the in vivo kinetics of glucose metabolism may provide a means for the early detection of the response of human breast cancer cells to estrogen versus tamoxifen treatment.

  5. Estrogen receptor beta and 2-arachydonoylglycerol mediate the suppressive effects of estradiol on frequency of postsynaptic currents in gonadotropin-releasing hormone neurons of metestrous mice: an acute slice electrophysiological study

    Directory of Open Access Journals (Sweden)

    Flóra eBálint

    2016-03-01

    Full Text Available Gonadotropin-releasing hormone (GnRH neurons are controlled by 17β-estradiol (E2 contributing to the steroid feedback regulation of the reproductive axis. In rodents, E2 exerts a negative feedback effect upon GnRH neurons throughout the estrus-diestrus phase of the ovarian cycle. The present study was undertaken to reveal the role of estrogen receptor subtypes in the mediation of the E2 signal and elucidate the downstream molecular machinery of suppression. The effect of E2 administration at low physiological concentration (10 pM on GnRH neurons in acute brain slices obtained from metestrous GnRH-GFP mice was studied under paradigms of blocking or activating estrogen receptor subtypes and interfering with retrograde 2-arachydonoylglycerol (2-AG signaling. Whole-cell patch clamp recordings revealed that E2 significantly diminished the frequency of spontaneous postsynaptic currents (sPSCs in GnRH neurons (49. 62±7.6% which effect was abolished by application of the ERα/β blocker Faslodex (1 µM. Pretreatment of the brain slices with cannabinoid receptor type 1 (CB1 inverse agonist AM251 (1 µM and intracellularly applied endocannabinoid synthesis blocker THL (10 µM significantly attenuated the effect of E2 on the sPSCs. E2 remained effective in the presence of TTX indicating a direct action of E2 on GnRH cells. The ERβ specific agonist DPN (10 pM also significantly decreased the frequency of miniature postsynaptic currents (mPSCs in GnRH neurons. In addition, the suppressive effect of E2 was completely blocked by the selective ERβ antagonist PHTPP (1 µM indicating that ERβ is required for the observed rapid effect of the E2. In contrast, the ERα agonist PPT (10 pM or the membrane-associated G protein-coupled estrogen receptor (GPR30 agonist G1 (10 pM had no significant effect on the frequency of mPSCs in these neurons. AM251 and THL significantly abolished the effect of E2 whereas AM251 eliminated the action of DPN on the mPSCs. These

  6. Environmental Estrogens and Breast cancer

    Directory of Open Access Journals (Sweden)

    llmiawati llmiawati

    2014-12-01

    Full Text Available Background: Recent studies revealed that various man-made chemicals disrupting properties with endocrine- contribute in the development of breast cancer.objective: To review the state of the science of the endocrine-disrupting chemicals (EDC and their role in the development of breast cancer.Methods: Key papers on experimental and epidemiologic studies examining the associations between EDC and breast cancer were searched throJgh the Google Sch-olar and pubMedusing Results: EDC effects depend on the level and timing of exposure, with critical window on developmentalstages. Diethylstilbestrol(DES and bispIenolA(BpA aretwo thoroughlystudied environmental estrogenic compounds. Epidemiological studies showed increased breast cancer incident in women exposed to DES during gestation. ExperimentalstuQies revealed that BPA induces architectural and gene expression froRte changes ir i"J"rt r;;;"ry gtand, with the stroma of fetal mammary gland as the primary target. ihe effects of these environmental estrogens are mostly mediated through the estrogen ieceptors a and B. Their exposure may further sensitize the mammary tissuelo the hit or otner carcinogens. Epigenome alteration in the mammary gland has also been implicated in its neoplastic dLvelopre"nt.Conclusions: Fetal and perinatal stages are the critical exposure windows to environmental estrogens and multiple mechanism is irnplicated in the development of breast cancer resulted from this exposure.

  7. Estrogens and aging skin

    OpenAIRE

    Thornton, M. Julie

    2013-01-01

    Estrogen deficiency following menopause results in atrophic skin changes and acceleration of skin aging. Estrogens significantly modulate skin physiology, targeting keratinocytes, fibroblasts, melanocytes, hair follicles and sebaceous glands, and improve angiogenesis, wound healing and immune responses. Estrogen insufficiency decreases defense against oxidative stress; skin becomes thinner with less collagen, decreased elasticity, increased wrinkling, increased dryness and reduced vascularity...

  8. Evidence of a correlation of estrogen receptor level and avian osteoclast estrogen responsiveness.

    Science.gov (United States)

    Pederson, L; Kremer, M; Foged, N T; Winding, B; Ritchie, C; Fitzpatrick, L A; Oursler, M J

    1997-05-01

    Isolated osteoclasts from 5-week-old chickens respond to estradiol treatment in vitro with decreased resorption activity, increased nuclear proto-oncogene expression, and decreased lysosomal enzyme secretion. This study examines osteoclasts from embryonic chickens and egg-laying hens for evidence of estrogen responsiveness. Although osteoclasts from both of these sources express estrogen receptor mRNA and protein, estradiol treatment had no effect on resorption activity. In contrast to the lack of effect on resorption, estradiol treatment for 30 minutes resulted in steady-state mRNA levels of c-fos and c-jun increasing in osteoclasts from embryonic chickens and decreasing in osteoclasts from egg-laying hens. These data suggest that a nuclear proto-oncogene response may not be involved in estradiol-mediated decreased osteoclast resorption activity. To examine the influence of circulating estrogen on osteoclast estrogen responsiveness, 5-week-old chickens were injected with estrogen for 4 days prior to sacrifice. Estradiol treatment of osteoclasts from these chickens did not decrease resorption activity in vitro. Transfection of an estrogen receptor expression vector into osteoclasts from the estradiol-injected chickens and egg-laying hens restored estrogen responsiveness. Osteoclasts from 5-week-old chickens and estradiol treated 5-week-old chickens transfected with the estrogen receptor expression vector contained significantly higher levels of estrogen receptor protein and responded to estradiol treatment by decreasing secretion of cathepsins B and L and tartrate-resistant acid phosphatase. In contrast, osteoclasts from embryonic chickens, egg-laying hens, and estradiol-treated 5-week-old chickens either untransfected or transfected with an empty expression vector did not respond similarly. These data suggest that modulation of osteoclast estrogen responsiveness may be controlled by changes in the osteoclast estrogen receptor levels.

  9. Evaluation of adverse effects in tamoxifen exposed healthy female dogs.

    Science.gov (United States)

    Tavares, Wanessa L F; Lavalle, Gleidice E; Figueiredo, Mariana S; Souza, Aline G; Bertagnolli, Angelica C; Viana, Fernando A B; Paes, Paulo R O; Carneiro, Rubens A; Cavalcanti, Guilherme A O; Melo, Marilia M; Cassali, Geovanni D

    2010-12-22

    Mammary tumors are among the most frequent neoplasms in female dogs, but the strategies employed in animal treatment are limited. In human medicine, hormone manipulation is used in cancer therapy. Tamoxifen citrate is a selective inhibitor of oestrogen receptors and exerts a potent anti-oestrogen effect on the mammary gland. The aim of this study was to evaluate the adverse effects when exposing healthy female dogs to tamoxifen. Tamoxifen was administered for 120 days at a dose of 0.5 or 0.8 mg/kg/day to either intact or spayed female dogs. The effects were assessed through clinical examination, haematology, serum biochemistry, ophthalmology and bone marrow aspirate examination. Ovariohysterectomy was performed and the uterus examined by histopathology. Vulva oedema and purulent vaginal discharge developed with 10 days of tamoxifen exposure in all groups. Pyometra was diagnosed after around 90 days of exposure in intact females with frequencies increasing during the following 30 days of exposure. Up to 50% of dogs within the groups developed retinitis but none of the dogs had signs of reduced visual acuity. The prevalence of retinitis in each group was similar after 120 days of exposure. Haematological, biochemical and bone marrow changes were not observed. Due to the high risk of developing pyometra after prolonged exposure to tamoxifen, only spayed animals should be given this medication. A dose of 0.8 mg tamoxifen/kg body weight/day is recommended when treating tamoxifen-responsive canine mammary tumors. Due to the high risk of developing pyometra, ovariohysterectomy is recommended.

  10. Evaluation of adverse effects in tamoxifen exposed healthy female dogs

    Directory of Open Access Journals (Sweden)

    Cavalcanti Guilherme AO

    2010-12-01

    Full Text Available Abstract Background Mammary tumors are among the most frequent neoplasms in female dogs, but the strategies employed in animal treatment are limited. In human medicine, hormone manipulation is used in cancer therapy. Tamoxifen citrate is a selective inhibitor of oestrogen receptors and exerts a potent anti-oestrogen effect on the mammary gland. The aim of this study was to evaluate the adverse effects when exposing healthy female dogs to tamoxifen. Methods Tamoxifen was administered for 120 days at a dose of 0.5 or 0.8 mg/kg/day to either intact or spayed female dogs. The effects were assessed through clinical examination, haematology, serum biochemistry, ophthalmology and bone marrow aspirate examination. Ovariohysterectomy was performed and the uterus examined by histopathology. Results Vulva oedema and purulent vaginal discharge developed with 10 days of tamoxifen exposure in all groups. Pyometra was diagnosed after around 90 days of exposure in intact females with frequencies increasing during the following 30 days of exposure. Up to 50% of dogs within the groups developed retinitis but none of the dogs had signs of reduced visual acuity. The prevalence of retinitis in each group was similar after 120 days of exposure. Haematological, biochemical and bone marrow changes were not observed. Due to the high risk of developing pyometra after prolonged exposure to tamoxifen, only spayed animals should be given this medication. Conclusions A dose of 0.8 mg tamoxifen/kg body weight/day is recommended when treating tamoxifen-responsive canine mammary tumors. Due to the high risk of developing pyometra, ovariohysterectomy is recommended.

  11. Effect of hormone replacement and selective estrogen receptor modulators (SERMs) on the biomechanics and biochemistry of pelvic support ligaments in the cynomolgus monkey (Macaca fascicularis).

    Science.gov (United States)

    Shahryarinejad, Azin; Gardner, Thomas R; Cline, J Mark; Levine, William N; Bunting, Haley A; Brodman, Michael D; Ascher-Walsh, Charles J; Scotti, Richard J; Vardy, Michael D

    2010-05-01

    To evaluate the effect of selective estrogen receptor modulators and ethinyl estradiol on the biomechanical and biochemical properties of the uterosacral and round ligaments in the monkey model of menopause. A randomized, double-blind, placebo-controlled study on 11 female macaque monkeys. Ovariectomized monkeys received 12 weeks of placebo, raloxifene, tamoxifen, or ethinyl estradiol. Biomechanical step-strain testing and real-time polymerase chain reaction was performed on the uterosacral and round ligaments. Tamoxifen and raloxifene uterosacrals expressed differing collagen I/III receptor density ratios, but both selective estrogen receptor modulators showed decreased tensile stiffness compared to ethinyl estradiol and controls. These findings support a possible effect of selective estrogen receptor modulators on biomechanical and biochemical properties of uterosacrals. This may play a role in pelvic organ prolapse. Copyright (c) 2010 Mosby, Inc. All rights reserved.

  12. A Chip for Estrogen Receptor Action: Detection of Biomarkers Released by MCF-7 Cells through Estrogenic and Anti-Estrogenic Effects

    Directory of Open Access Journals (Sweden)

    Konstanze Gier

    2017-08-01

    Full Text Available The fluorescence-based multi-analyte chip platform for the analysis of estrogenic and anti-estrogenic substances is a new in vitro tool for the high throughput screening of environmental samples. In contrast to existing tools, the chip investigates the complex action of xenoestrogens in a human cell model by characterizing protein expression. It allows for the quantification of 10 proteins secreted by MCF-7 cells, representing various biological and pathological endpoints of endocrine action and distinguishing between estrogen- and anti-estrogen-dependent secretion of proteins. Distinct protein secretion patterns of the cancer cell line after exposure to known estrogen receptor agonists ß-estradiol, bisphenol A, genistein, and nonylphenol as well as antagonists fulvestrant and tamoxifen demonstrate the potential of the chip. Stimulation of cells with Interleukin-1ß shifts concentrations of low abundant biomarkers towards the working range of the chip. In the non-stimulated cell culture, Matrix Metalloproteinase 9 (MMP-9 and Vascular Endothelial Growth Factor (VEGF show differences upon treatment with antagonists and agonists of the estrogen receptor. In stimulated MCF-7 cells challenged with receptor agonists secretion of Monocyte Chemoattractant Protein (MCP-1, Interleukin-6 (IL-6, Rantes, and Interleukin-8 (IL-8 significantly decreases. In parallel, the proliferating effect of endocrine-disrupting substances in MCF-7 cells is assessed in a proliferation assay based on resazurin. Using ethanol as a solvent for test substances increases the background of proliferation and secretion experiments, while using dimethyl sulfoxide (DMSO does not show any adverse effects. The role of the selected biomarkers in different physiological processes such as cell development, reproduction, cancer, and metabolic syndrome makes the chip an excellent tool for either indicating endocrine-disrupting effects in food and environmental samples, or for screening the

  13. Nuclear respiratory factor-1 and bioenergetics in tamoxifen-resistant breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Radde, Brandie N.; Ivanova, Margarita M.; Mai, Huy Xuan; Alizadeh-Rad, Negin; Piell, Kellianne; Van Hoose, Patrick; Cole, Marsha P.; Muluhngwi, Penn; Kalbfleisch, Ted S. [Department of Biochemistry & Molecular Genetics, Center for Genetics and Molecular Medicine, University of Louisville School of Medicine, Louisville, KY 40292 (United States); Rouchka, Eric C. [Bioinformatics and Biomedical Computing Laboratory, Department of Computer Engineering and Computer Science, University of Louisville, Louisville, KY 40292 (United States); Hill, Bradford G. [Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40292 (United States); Klinge, Carolyn M., E-mail: carolyn.klinge@louisville.edu [Department of Biochemistry & Molecular Genetics, Center for Genetics and Molecular Medicine, University of Louisville School of Medicine, Louisville, KY 40292 (United States)

    2016-09-10

    Acquired tamoxifen (TAM) resistance is a significant clinical problem in treating patients with estrogen receptor α (ERα)+ breast cancer. We reported that ERα increases nuclear respiratory factor-1 (NRF-1), which regulates nuclear-encoded mitochondrial gene transcription, in MCF-7 breast cancer cells and NRF-1 knockdown stimulates apoptosis. Whether NRF-1 and target gene expression is altered in endocrine resistant breast cancer cells is unknown. We measured NRF-1and metabolic features in a cell model of progressive TAM-resistance. NRF-1 and its target mitochondrial transcription factor A (TFAM) were higher in TAM-resistant LCC2 and LCC9 cells than TAM-sensitive MCF-7 cells. Using extracellular flux assays we observed that LCC1, LCC2, and LCC9 cells showed similar oxygen consumption rate (OCR), but lower mitochondrial reserve capacity which was correlated with lower Succinate Dehydrogenase Complex, Subunit B in LCC1 and LCC2 cells. Complex III activity was lower in LCC9 than MCF-7 cells. LCC1, LCC2, and LCC9 cells had higher basal extracellular acidification (ECAR), indicating higher aerobic glycolysis, relative to MCF-7 cells. Mitochondrial bioenergetic responses to estradiol and 4-hydroxytamoxifen were reduced in the endocrine-resistant cells compared to MCF-7 cells. These results suggest the acquisition of altered metabolic phenotypes in response to long term antiestrogen treatment may increase vulnerability to metabolic stress. - Highlights: • NRF-1 and TFAM expression are higher in endocrine-resistant breast cancer cells. • Oxygen consumption rate is similar in endocrine-sensitive and resistant cells. • Mitochondrial reserve capacity is lower in endocrine-resistant cells. • Endocrine-resistant breast cancer cells have increased glycolysis. • Bioenergetic responses to E2 and tamoxifen are lower in endocrine-resistant cells.

  14. Discrepancy between ultrasonography and hysteroscopy and histology of endometrium in postmenopausal breast cancer patients using tamoxifen

    NARCIS (Netherlands)

    Mourits, MJE; Van der Zee, AGJ; Willemse, PHB; Ten Hoor, KA; Hollema, H; De Vries, EGE

    Background. The increased risk of endometrial carcinoma following the use of tamoxifen has stimulated studies on endometrial diagnostic screening methods. In tamoxifen users the endometrial thickening observed with transvaginal ultrasonography (TVU) frequently cannot be confirmed by hysteroscopy or

  15. Detection of estrogenic activity in sediment-associated compounds using in vitro reporter gene assays

    NARCIS (Netherlands)

    Legler, J.; Dennekamp, M.; Vethaak, A.D.; Brouwer, A.; Koeman, J.H.; Burg, van der B.; Murk, A.J.

    2002-01-01

    Sediments may be the ultimate sink for persistent (xeno-) estrogenic compounds released into the aquatic environment. Sediment-associated estrogenic potency was measured with an estrogen receptor-mediated luciferase reporter gene (ER-CALUX) assay and compared with a recombinant yeast screen. The

  16. Estrogen regulates the expression of cathepsin E-A-like gene via ...

    Indian Academy of Sciences (India)

    徐春林

    by estrogen, and the regulative effect was predominantly mediated via ER-β in chicken liver. Keywords: Estrogen ... the RNA-seq technique to investigate the mechanism of hepatic lipid metabolism (Li et al. 2015). ... To clone the cathepsin E-A-like gene and investigate the effect of estrogen on expression of the gene, a total ...

  17. Melanocortin 4 receptor is not required for estrogenic regulations on energy homeostasis and reproduction

    Science.gov (United States)

    Brain estrogen receptor-a (ERa) is essential for estrogenic regulation of energy homeostasis and reproduction. We previously showed that ERa expressed by pro-opiomelanocortin (POMC) neurons mediates estrogen's effects on food intake, body weight, negative regulation of hypothalamic–pituitary–gonadal...

  18. Augmentation of Endoxifen Exposure in Tamoxifen-Treated Women Following SSRI Switch

    NARCIS (Netherlands)

    L. Binkhorst (Lisette); M. Bannink (Marjolein); P. de Bruijn (Peter); J.B. Ruit (Jos); J. Droogendijk (Jolanda); R.J. van Alphen (Robbert); T.D. den Boer (Tilly D.); M.H. Lam (Mei); A. Jager (Agnes); T. van Gelder (Teun); A.H.J. Mathijssen (Ron)

    2016-01-01

    textabstractBackground and Objective: The anti-oestrogen tamoxifen requires metabolic activation to endoxifen by cytochrome P450 (CYP) enzymes, predominantly CYP2D6. Potent CYP2D6-inhibiting antidepressants can seriously disrupt tamoxifen metabolism, probably influencing the efficacy of tamoxifen.

  19. LAMP3 is involved in tamoxifen resistance in breast cancer cells through the modulation of autophagy

    NARCIS (Netherlands)

    Nagelkerke, A.P.; Sieuwerts, A.M.; Bussink, J.; Sweep, F.C.; Look, M.P.; Foekens, J.A.; Martens, J.W.; Span, P.N.

    2014-01-01

    Lysosome-associated membrane protein 3 (LAMP3) is a member of the LAMP-family of proteins, which are involved in the process of autophagy. Autophagy is induced by tamoxifen in breast cancer cells and may contribute to tamoxifen resistance. In this study, the significance of LAMP3 for tamoxifen

  20. Dutasteride-mediated morphological changes in the genitourinary tract associated with altered expression patterns of the androgen and estrogen receptors in male rats.

    Science.gov (United States)

    Enatsu, N; Chiba, K; Sumii, K; Fukuda, T; Okada, K; Matsushita, K; Fujisawa, M

    2017-03-01

    We evaluated the effects of dutasteride on the genitourinary tract using fifteen 8-week-old male Sprague-Dawley rats. Animals were divided into three groups comprising five animals each and treated as follows. Group A was a control group, members of Group B received oral administration of dutasteride 0.1 mg/kg/day from the age of 8 to 16 weeks, and members of Group C were castrated at the age of 8 weeks. All rats were killed at the age of 16 weeks for the sample collection of blood, bladder, prostate, seminal vesicles, and penis. Then, we evaluated the pathological examination for evaluating the tissue fibrosis and hormonal receptor expression. The results showed that the mean size of the prostate and seminal vesicles was smaller in Group B and Group C than in Group A. Serum and tissue concentrations of both testosterone and dihydrotestosterone were remarkably reduced in serum and all tissues in Group C compared with Group A. On the other hand, in Group B, only dihydrotestosterone was reduced in serum and penis. Histopathological examination revealed that Group C showed statistically significant histological changes, such as an increase in fibrotic tissue in the bladder, prostate, and penis. Similarly, Group B showed fibrotic changes in the prostate and penis compared with the Group A. Immunofluorescent staining revealed that the androgen receptor was more strongly expressed than the estrogen receptor beta in Group A. On the other hand, in Group C, weak expression of the androgen receptor and strong expression of the estrogen receptor beta was noted. In Group B, these changes were noted in the prostate and penis. These findings suggest that dutasteride cause morphological changes not only in prostate but also in penis. These changes are associated with altered expression patterns of androgen receptor and estrogen receptor. © 2016 American Society of Andrology and European Academy of Andrology.

  1. Estrogen replacement therapy and cardioprotection: mechanisms and controversies

    Directory of Open Access Journals (Sweden)

    M.T.R. Subbiah

    2002-03-01

    Full Text Available Epidemiological and case-controlled studies suggest that estrogen replacement therapy might be beneficial in terms of primary prevention of coronary heart disease (CHD. This beneficial effect of estrogens was initially considered to be due to the reduction of low density lipoproteins (LDL and to increases in high density lipoproteins (HDL. Recent studies have shown that estrogens protect against oxidative stress and decrease LDL oxidation. Estrogens have direct effects on the arterial tissue and modulate vascular reactivity through nitric oxide and prostaglandin synthesis. While many of the effects of estrogen on vascular tissue are believed to be mediated by estrogen receptors alpha and ß, there is evidence for `immediate non-genomic' effects. The role of HDL in interacting with 17ß-estradiol including its esterification and transfer of esterified estrogens to LDL is beginning to be elucidated. Despite the suggested positive effects of estrogens, two recent placebo-controlled clinical trials in women with CHD did not detect any beneficial effects on overall coronary events with estrogen therapy. In fact, there was an increase in CHD events in some women. Mutations in thrombogenic genes (factor V Leiden, prothrombin mutation, etc. in a subset of women may play a role in this unexpected finding. Thus, the cardioprotective effect of estrogens appears to be more complicated than originally thought and requires more research.

  2. Pomegranate extract demonstrate a selective estrogen receptor modulator profile in human tumor cell lines and in vivo models of estrogen deprivation.

    Science.gov (United States)

    Sreeja, Sreekumar; Santhosh Kumar, Thankayyan R; Lakshmi, Baddireddi S; Sreeja, Sreeharshan

    2012-07-01

    Selective estrogen receptor modulators (SERMs) are estrogen receptor (ER) ligands exhibiting tissue-specific agonistic or antagonistic biocharacter and are used in the hormonal therapy for estrogen-dependent breast cancers. Pomegranate fruit has been shown to exert antiproliferative effects on human breast cancer cells in vitro. In this study, we investigated the tissue-specific estrogenic/antiestrogenic activity of methanol extract of pericarp of pomegranate (PME). PME was evaluated for antiproliferative activity at 20-320 μg/ml on human breast (MCF-7, MDA MB-231) endometrial (HEC-1A), cervical (SiHa, HeLa), ovarian (SKOV3) carcinoma and normal breast fibroblast (MCF-10A) cells. Competitive radioactive binding studies were carried out to ascertain whether PME interacts with ER. The reporter gene assay measured the estrogenic/antiestrogenic activity of PME in MCF-7 and MDA MB-231 cells transiently transfected with plasmids coding estrogen response elements with a reporter gene (pG5-ERE-luc) and wild-type ERα (hEG0-ER). PME inhibited the binding of [³H] estradiol to ER and suppressed the growth and proliferation of ER-positive breast cancer cells. PME binds ER and down-regulated the transcription of estrogen-responsive reporter gene transfected into breast cancer cells. The expressions of selected estrogen-responsive genes were down-regulated by PME. Unlike 17β-estradiol [1 mg/kg body weight (BW)] and tamoxifen (10 mg/kg BW), PME (50 and 100 mg/kg BW) did not increase the uterine weight and proliferation in ovariectomized mice and its cardioprotective effects were comparable to that of 17β-estradiol. In conclusion, our findings suggest that PME displays a SERM profile and may have the potential for prevention of estrogen-dependent breast cancers with beneficial effects in other hormone-dependent tissues. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Estrogens and development

    Energy Technology Data Exchange (ETDEWEB)

    McLachlan, J.A.; Newbold, R.R.

    1987-11-01

    The normal development of the genital organs of mammals, including humans, is under hormonal control. A role for the female sex hormone estrogen in this process is still unclear. However, exposure of experimental animals or humans to the potent exogenous estrogen, diethylstilbestrol (DES), results in persistent differentiation effects. Since many chemicals in the environment are weakly estrogenic, the possibility of hormonally altered differentiation must be considered.

  4. Targeted estrogen delivery reverses the metabolic syndrome

    NARCIS (Netherlands)

    Finan, Brian; Yang, Bin; Ottaway, Nickki; Stemmer, Kerstin; Müller, Timo D.; Yi, Chun-Xia; Habegger, Kirk; Schriever, Sonja C.; García-Cáceres, Cristina; Kabra, Dhiraj G.; Hembree, Jazzminn; Holland, Jenna; Raver, Christine; Seeley, Randy J.; Hans, Wolfgang; Irmler, Martin; Beckers, Johannes; de Angelis, Martin Hrabě; Tiano, Joseph P.; Mauvais-Jarvis, Franck; Perez-Tilve, Diego; Pfluger, Paul; Zhang, Lianshan; Gelfanov, Vasily; DiMarchi, Richard D.; Tschöp, Matthias H.

    2012-01-01

    We report the development of a new combinatorial approach that allows for peptide-mediated selective tissue targeting of nuclear hormone pharmacology while eliminating adverse effects in other tissues. Specifically, we report the development of a glucagon-like peptide-1 (GLP-1)-estrogen conjugate

  5. Estrogens in breast cancer

    International Nuclear Information System (INIS)

    Terzieff, V.; Vázquez, A.

    2004-01-01

    The prolonged exposure to estrogen increases the risk of cancer breast, the precise role of estrogen in the carcinogenesis process is unclear. They are capable of inducing cell proliferation through different channels receptor Estrogen (ER) known, for example through MAPkinasa sensitivity the promoter of proliferation effect depends on the level of RE, or type to â, integrity (mutations may alter its function) and ligand. The different types of estrogens and related compounds have different profile of affinity for RE and effect end. The modulatory role of progestogens proliferation is very complex, and the interaction between the effector pathways of progestin’s, estrogens, EGF and IGF family - maybe others - determines the final effect .. Estrogens are mutagenic per se weak, but is now known for its hepatic metabolism occur highly reactive species such as quinones, and catechol, powerful mutagens in vitro. Direct or indirect genotoxicity probably explains Part of the effects of estrogen on tumor cells. The use of hormone replacement (HTR) increases the risk of CM, as proportional to the time of use. The combination with progestin seems to be increased risk (R R 2). It is unclear the role of phyto estrogens in the prevention the CM. In the male breast is known that the proliferative response to parenchymal different hormonal maneuvers is different. The effect is minimal castration are and maximum with the combination of estrogen and progesterone. It is unclear, however, the risk of the population exposed to hormone therapy for cancer prostate or otherwise

  6. In vivo imaging of brain estrogen receptors in rats : a 16α-18F-fluoro-17β-estradiol PET study

    NARCIS (Netherlands)

    Khayum, Mohammed A; de Vries, Erik F J; Glaudemans, Andor W J M; Dierckx, Rudi A J O; Doorduin, Janine

    UNLABELLED: The steroid hormone estrogen is important for brain functioning and is thought to be involved in brain diseases, such as Alzheimer disease and depression. The action of estrogen is mediated by estrogen receptors (ERs). To understand the role of estrogens in brain functioning, it is

  7. Side effects associated with ultrarapid cytochrome P450 2D6 genotype among women with early stage breast cancer treated with tamoxifen.

    Science.gov (United States)

    Rolla, R; Vidali, M; Meola, S; Pollarolo, P; Fanello, M R; Nicolotti, C; Saggia, C; Forti, L; Agostino, F D; Rossi, V; Borra, G; Stratica, F; Alabiso, O; Bellomo, G

    2012-01-01

    The side effects of tamoxifen, a drug widely used for the treatment and the prevention of recurrence in patients with estrogen receptor positive breast cancers (ER+), have been reported in clinical trials, but to date no information is available on their possible association with an increased enzymatic activity of CYP2D6 (ultra-metabolizers, UMs). The aim of this study was therefore to evaluate the association between the presence of multiple functional CYP2D6 alleles and the occurrence of side effects. 61 women with ER+ breast cancer receiving tamoxifen monotherapy were investigated in order to assess the relationships between CYP2D6 UM phenotype and side effects. Genotyping of 16 CYP2D6 polymorphisms was performed using a new DNA microarray technology. A highly significant difference was detected (41.2% of difference, 95% CI 6 - 61%, Fisher's exact test, p = 0.030) between the numbers of Ultrarapid Metabolizer patients (UM; high activity) with two or more adverse drug reactions to tamoxifen (7/9; 77.8%), compared to the number of Extensive Metabolizers (EM; normal activity), Intermediate Metabolizers (IM; reduced activity), and Poor Metabolizers (PM; no activity) with at least two side effects (19/52, 36.5%). A similar difference was also observed comparing the two groups (UM vs EM-IM-PM) for the number of side effects (median and inter quartile range, IQR: AM/EM/IM 1, IQR 0-2 vs. ULTRA 2, IQR 2-4; Mann-Whitney p = 0.005). Our results suggest a new association between CYP2D6 gene duplication and side effects to tamoxifen, indicating a possible role of CYP2D6 in their occurrence.

  8. Ano1/TMEM16A Overexpression Is Associated with Good Prognosis in PR-Positive or HER2-Negative Breast Cancer Patients following Tamoxifen Treatment.

    Directory of Open Access Journals (Sweden)

    Huizhe Wu

    Full Text Available The calcium-activated chloride channel Ano1 (TMEM16A is overexpressed in many tumors. Although Ano1 overexpression is found in breast cancer due to 11q13 amplification, it remains unclear whether signaling pathways are involved in Ano1 overexpression during breast cancer tumorigenesis in vivo. Estrogen receptor (ER, progesterone receptor (PR, and human epidermal growth factor receptor 2 (HER2 have been known to contribute to breast cancer progression. It is unclear whether Ano1 is associated with clinical outcomes in breast cancer patients with different ER, PR and HER2 status. In the present study, we investigated the Ano1 expression in 431 patients with invasive ductal breast carcinoma and 46 patients with fibroadenoma, using immunohistochemistry, and analyzed the association between Ano1 expression and clinical characteristics and outcomes of breast cancer patients with different ER, PR, and HER2 status. Ano1 was overexpressed in breast cancer compared with fibroadenoma. Ano1 was significantly more associated with breast cancer with the lower clinical stage (stage I or II, or triple-negative status. Mostly importantly, Ano1 overexpression was associated with good prognosis in patients with the PR-positive or HER2-negative status, and in patients following tamoxifen treatment. Multivariate Cox regression analysis showed that Ano1 overexpression was a prognostic factor for longer overall survival in PR-positive or HER2-negative patients, and a predictive factor for longer overall survival in patients following tamoxifen treatment. Our findings suggest that Ano1 may be a potential marker for good prognosis in PR-positive or HER2-negative patients following tamoxifen treatment. The PR and HER2 status defines a subtype of breast cancer in which Ano1 overexpression is associated with good prognosis following tamoxifen treatment.

  9. Aurora kinase B is important for antiestrogen resistant cell growth and a potential biomarker for tamoxifen resistant breast cancer.

    Science.gov (United States)

    Larsen, Sarah L; Yde, Christina W; Laenkholm, Anne-Vibeke; Rasmussen, Birgitte B; Duun-Henriksen, Anne Katrine; Bak, Martin; Lykkesfeldt, Anne E; Kirkegaard, Tove

    2015-04-08

    Resistance to antiestrogen therapy is a major clinical challenge in the treatment of estrogen receptor α (ER)-positive breast cancer. The aim of the study was to explore the growth promoting pathways of antiestrogen resistant breast cancer cells to identify biomarkers and novel treatment targets. Antiestrogen sensitive and resistant T47D breast cancer cell lines were used as model systems. Parental and fulvestrant resistant cell lines were subjected to a kinase inhibitor library. Kinase inhibitors preferentially targeting growth of fulvestrant resistant cells were identified and the growth inhibitory effect verified by dose-response cell growth experiments. Protein expression and phosphorylation were investigated by western blot analysis. Cell cycle phase distribution and cell death were analyzed by flow cytometry. To evaluate Aurora kinase B as a biomarker for endocrine resistance, immunohistochemistry was performed on archival primary tumor tissue from breast cancer patients who have received adjuvant endocrine treatment with tamoxifen. The selective Aurora kinase B inhibitor barasertib was identified to preferentially inhibit growth of fulvestrant resistant T47D breast cancer cell lines. Compared with parental cells, phosphorylation of Aurora kinase B was higher in the fulvestrant resistant T47D cells. Barasertib induced degradation of Aurora kinase B, caused mitotic errors, and induced apoptotic cell death as measured by accumulation of SubG1 cells and PARP cleavage in the fulvestrant resistant cells. Barasertib also exerted preferential growth inhibition of tamoxifen resistant T47D cell lines. Finally, high percentage of Aurora kinase B positive tumor cells was significantly associated with reduced disease-free and overall survival in 261 ER-positive breast cancer patients, who have received tamoxifen as first-line adjuvant endocrine treatment. Our results indicate that Aurora kinase B is a driving factor for growth of antiestrogen resistant T47D breast

  10. Risk of endometrial cancer after tamoxifen treatment of breast cancer

    NARCIS (Netherlands)

    F.E. van Leeuwen (Flora); J. Benraadt (J.); J.W.W. Coebergh (Jan Willem); L.A.L.M. Kiemeney (Bart); C.H.F. Gimbrère (Charles); R. Otter (Renée); L.J. Scheuten (Leo); R.A. Damhuis (Ronald); M. Bontenbal (Marijke); A.I. Diepenhorst; A.W. van den Belt-Dusebout (Alexandra); H. van Tinteren (Harm)

    1994-01-01

    textabstractSince large trials have been set up to assess whether tamoxifen decreases the risk of breast cancer in healthy women, it has become important to investigate the drug's potential adverse effects, including occurrence of endometrial cancer. We undertook a case-control study in the

  11. Tamoxifen treatment and gynecologic side effects : A review

    NARCIS (Netherlands)

    Mourits, MJE; De Vries, EGE; Willemse, PHB; Ten Hoor, KA; Hollema, H; Van der Zee, AGJ

    Objective: To review the literature on tamoxifen side effects on the female genital tract and psychosexual function in premenopausal and postmenopausal women. Data Sources: We used the English-language literature in MEDLINE and reference lists from selected articles. Search terms included:

  12. Adenosarcoma of the uterus following tamoxifen treatment for breast cancer

    NARCIS (Netherlands)

    Mourits, MJE; Hollema, H; Willemse, PHB; De Vries, EGE; Aalders, JG; Van der Zee, AGJ

    1998-01-01

    A 71-year-old patient developed an uterine adenosarcoma two months after two years of tamoxifen adjuvant treatment for early breast cancer. After curettage for postmenopausal bleeding, the patient underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy and pelvic

  13. Detection of tamoxifen metabolites by GC-MSD.

    Science.gov (United States)

    Báez, H; Camargo, C; Osorio, H; Umpiérrez, F

    2004-01-01

    Tamoxifen is an antiestrogen used in the adjuvant endocrine therapy of early breast cancer and malignant breast disorders. It is also used in women with anovulatory infertility caused by its stimulating effect on the secretion of the pituitary gonadotrophic hormones. In males it could increase the endogenous production of androgens. Because of these properties tamoxifen may be misused in some sports to treat the androgens suppression caused by the extensive abuse of anabolic androgenic steroids. A method for identification and confirmation of tamoxifen metabolites is described. Hydroxymetoxytamoxifen is detected in urine by gas chromatography and mass spectrometry in a selective ion monitoring method followed by the routine postrun in the screening of anabolic steroids. Once the hydroxymetoxytamoxifen is detected, confirmation of reported metabolites could be performed with a 5973 mass selective detector in the scan mode after solid-phase extraction by cationic exchange. This study also reports an excretion profile for a single dose of tamoxifen equivalent to 40 mg administrated orally to two males volunteers.

  14. Transcriptional Inhibition of Matrix Metal loproteinase 9 (MMP-9 Activity by a c-fos/Estrogen Receptor Fusion Protein is Mediated by the Proximal AP-1 Site of the MMP-9 Promoter and Correlates with Reduced Tumor Cell Invasion

    Directory of Open Access Journals (Sweden)

    David L. Crowe

    1999-10-01

    Full Text Available Tumor cell invasion of basement membranes is one of the hallmarks of malignant transformation. Tumor cells secrete proteolytic enzymes known as matrix metalloproteinases (MMPs which degrade extracellular matrix molecules. Increased expression of MMP-9 has been associated with acquisition of invasive phenotype in many tumors. However, multiple mechanisms for regulation of MMP-9 gene expression by tumor cell lines have been proposed. A number of transcription factor binding sites have been characterized in the upstream regulatory region of the MMP-9 gene, including those for AP-1. To determine how a specific AP-1 family member, c-fos, regulates MMP-9 promoter activity through these sites, we used an expression vector containing the c-fos coding region fused to the estrogen receptor (ER ligand binding domain. This construct is activated upon binding estradiol. Stable expression of this construct in ER negative squamous cell carcinoma (SCC lines produced an estradiol dependent decrease in the number of cells that migrated through a reconstituted basement membrane. This decreased invasiveness was accompanied by estradiol dependent downregulation of MMP-9 activity as determined by gelatin zymography. Estradiol also produced transcriptional downregulation of an MMP-9 promoter construct in cells transiently transfected with the c-fosER expression vector. This downregulation was mediated by the AP-1 site at —79 by in the MMP-9 promoter. We concluded that the proximal AP-1 site mediated the transcriptional downregulation of the MMP-9 promoter by a conditionally activated c-fos fusion protein.

  15. Feature of amenorrhea in postoperative tamoxifen users with breast cancer.

    Science.gov (United States)

    Kim, Hoon; Han, Wonshik; Ku, Seung Yup; Suh, Chang Suk; Kim, Seok Hyun; Choi, Young Min

    2017-03-01

    Tamoxifen has been used to prevent the recurrence of breast cancer. However, tamoxifen-users frequently experience amenorrhea and it can be confused from that caused by other hormonal abnormalities. In amenorrheic patients without breast cancer, clinicians usually measure the sex hormone levels that are known to be associated with ovarian or menstrual function. This study aimed to investigate the feature of female sex hormones in premenopausal breast cancer patients undergoing tamoxifen treatment. The medical records of fifty-nine premenopausal breast cancer patients who underwent tamoxifen treatment were reviewed retrospectively. The study population consisted of amenorrheic patients (n=36) and patients with menstruation (n=23). Serum hormone levels were measured either specifically between cycle days 2 and 5 in menstruating patients or at any time in amenorrheic participants. Serum levels of lutenizing hormone and estradiol were not statistically different according to the presence of menstruation. Serum follicle stimulating hormone level was significantly higher in amenorrheic patients (8.1±5.7 mIU/mL) than those in menstruating subjects (5.1±2.2 mIU/mL) (p=0.01). Serum concentration of thyroid stimulating hormone was lower in patients with amenorrhea (1.5±0.9 vs. 2.3±2.2 μIU/mL, p=0.04), although the prevalence of hypo- or hyperthyroidism was not different according to the pattern of menstruation. Menstruation status and hormone levels can be influenced by tamoxifen use in reproductive age breast cancer patients. Physicians should be attentive to the alteration of pituitary hormone levels in addition to sex steroid hormones in this population. Copyright © 2017. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology

  16. Effect of paclitaxel, epirubicin and tamoxifen on labelling index in cultured ehrlich ascites tumor cells

    International Nuclear Information System (INIS)

    Arican, G. Oe.; Oezalpan, A.

    2001-01-01

    The effect of Paclitaxel (PAC), Epirubicin (EPR) and Tamoxifen (TAM) on ''3H-thymidine labelling index (''3H-TdR LI) of Ehrlich ascites tumor cells (EAT) was investigated in cultured. In the present study, an estrogen receptor positive ER(+) hyper diploid cell lines were studied. We used optimum doses of PAC, EPR and TAM (12 mg/ml, 12 mg/ml and 2 mg/ml, respectively). Cells were treated with these doses for 0, 4, 8, 16 and 32 hours. At the end of these periods, both control and treated cells were labelled for 5 mCi/ml 3H-thymidine for 30 minutes. The results showed that inhibition of DNA synthesis in cultured EAT cells were increased in the combined treatment of two drugs when compared to the treatment of a single drug (p<0.01). In the treatment of three drugs, however, this effect reached a maximum (p<0.001). As a result, PAC+EPR+TAM treatment's had a maximum synergistic effect at 4 hours treatment

  17. [Antidepressants agents in breast cancer patients using tamoxifen: review of basic and clinical evidence].

    Science.gov (United States)

    Irarrázaval O, María Elisa; Gaete G, Leonardo

    2016-10-01

    Tamoxifen (Tmf), is a standard of care for women with estrogen receptor positive (ER+) breast cancer. Endoxifen is a Tmf metabolite generated by cytochrome P450 2D6 (CYP2D6). Antidepressive agents (AD) are often prescribed to women with breast cancer not only for depression, but also for anxiety and hot flashes. Some AD are substrates or inhibitors of the Tmf metabolic pathway. Therefore there may be interactions when Tmf and AD are prescribed simultaneously. Oncologic protection afforded by Tmf may become less effective or null when AD are indicated, especially in poor metabolizing patients. We performed an update of the literature about the criteria for choosing AD in women receiving Tmf. Tricyclic AD, paroxetine and fluoxetine should be avoided in patients receiving Tmf, because they are strong inhibitors of CYP2D6. Bupropion, duloxetine and sertraline are only moderate inhibitors of the cytochrome and are not contraindicated. Citalopram, desvenlafaxine, escitalopram, milnacipran and venlafaxine are recommended, because they do not influence the metabolism and clinical efficacy of Tmf and have fewer drug interactions. However, other additional pharmacological and clinical issues should be considered when choosing an antidepressant in women with breast cancer.

  18. 17β-estradiol induces stearoyl-CoA desaturase-1 expression in estrogen receptor-positive breast cancer cells

    International Nuclear Information System (INIS)

    Belkaid, Anissa; Duguay, Sabrina R.; Ouellette, Rodney J.; Surette, Marc E.

    2015-01-01

    To sustain cell growth, cancer cells exhibit an altered metabolism characterized by increased lipogenesis. Stearoyl-CoA desaturase-1 (SCD-1) catalyzes the production of monounsaturated fatty acids that are essential for membrane biogenesis, and is required for cell proliferation in many cancer cell types. Although estrogen is required for the proliferation of many estrogen-sensitive breast carcinoma cells, it is also a repressor of SCD-1 expression in liver and adipose. The current study addresses this apparent paradox by investigating the impact of estrogen on SCD-1 expression in estrogen receptor-α-positive breast carcinoma cell lines. MCF-7 and T47D mammary carcinomas cells and immortalized MCF-10A mammary epithelial cells were hormone-starved then treated or not with 17β-estradiol. SCD-1 activity was assessed by measuring cellular monounsaturated/saturated fatty acid (MUFA/SFA) ratios, and SCD-1 expression was measured by qPCR, immunoblot, and immunofluorescence analyses. The role of SCD-1 in cell proliferation was measured following treatment with the SCD-1 inhibitor A959372 and following SCD-1 silencing using siRNA. The involvement of IGF-1R on SCD-1 expression was measured using the IGF-1R antagonist AG1024. The expression of SREBP-1c, a transcription factor that regulates SCD-1, was measured by qPCR, and by immunoblot analyses. 17β-estradiol significantly induced cell proliferation and SCD-1 activity in MCF-7 and T47D cells but not MCF-10A cells. Accordingly, 17β-estradiol significantly increased SCD-1 mRNA and protein expression in MCF-7 and T47D cells compared to untreated cells. Treatment of MCF-7 cells with 4-OH tamoxifen or siRNA silencing of estrogen receptor-α largely prevented 17β-estradiol-induced SCD-1 expression. 17β-estradiol increased SREBP-1c expression and induced the mature active 60 kDa form of SREBP-1. The selective SCD-1 inhibitor or siRNA silencing of SCD-1 blocked the 17β-estradiol-induced cell proliferation and increase in

  19. Quality of life in relation to tamoxifen or exemestane treatment in postmenopausal breast cancer patients: a Tamoxifen Exemestane Adjuvant Multinational (TEAM) Trial side study

    NARCIS (Netherlands)

    van Nes, J. G. H.; Fontein, D. B. Y.; Hille, E. T. M.; Voskuil, D. W.; van Leeuwen, F. E.; de Haes, J. C. J. M.; Putter, H.; Seynaeve, C.; Nortier, J. W. R.; van de Velde, C. J. H.

    2012-01-01

    Tamoxifen and aromatase inhibitors are associated with side effects which can significantly impact quality of life (QoL). We assessed QoL in the Tamoxifen Exemestane Adjuvant Multinational (TEAM) Trial and compared these data with reported adverse events in the main database. 2,754 Dutch

  20. Quality of life in relation to tamoxifen or exemestane treatment in postmenopausal breast cancer patients : a Tamoxifen Exemestane Adjuvant Multinational (TEAM) Trial side study

    NARCIS (Netherlands)

    van Nes, J. G. H.; Fontein, D. B. Y.; Hille, E. T. M.; Voskuil, D. W.; van Leeuwen, F. E.; de Haes, J. C. J. M.; Putter, H.; Seynaeve, C.; Nortier, J. W. R.; van de Velde, C. J. H.

    Tamoxifen and aromatase inhibitors are associated with side effects which can significantly impact quality of life (QoL). We assessed QoL in the Tamoxifen Exemestane Adjuvant Multinational (TEAM) Trial and compared these data with reported adverse events in the main database. 2,754 Dutch

  1. Development and validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of tamoxifen, anastrozole, and letrozole in human plasma and its application to a clinical study.

    Science.gov (United States)

    Beer, Beate; Schubert, Birthe; Oberguggenberger, Anne; Meraner, Verena; Hubalek, Michael; Oberacher, Herbert

    2010-10-01

    There is substantial evidence that circulating estrogens promote the proliferation of breast cancer. Consequently, adjuvant hormonal treatment strategies targeting estrogen action have been established. Such hormonal therapies include selective estrogen receptor modulators, such as tamoxifen, which interfere at the estrogen receptors directly, or non-steroidal aromatase inhibitors, such as anastrozole and letrozole, which inhibit estrogen synthesis through blocking the aromatase, a key enzyme of estrogen production. Despite considerable therapeutic success, in several cases, the use of these drugs is limited by side effects that have been described to significantly impair the adherence of patients to endocrine treatment. However, objective data concerning patient adherence and its clinical relevance are limited. One promising approach to check patient-reported adherence is drug monitoring in human plasma. Therefore, a liquid chromatography-tandem mass spectrometry method to determine the plasma concentrations of tamoxifen, anastrozole, and letrozole has been developed and fully validated according to guidelines for clinical and forensic toxicology. The validation criteria evaluated were selectivity, linearity, accuracy and precision, limit of quantification, recovery and matrix effects, sample stability, and carryover. The six-point calibration curves showed linearity over the range of concentrations from 25 to 500 ng/ml for tamoxifen, 5 to 200 ng/ml for anastrozole, and 10 to 300 ng/ml for letrozole. The intra- and inter-day precision and accuracies were always better than 15%. The validated procedure was successfully applied to a clinical study (Patient-Reported Outcomes in Breast Cancer Patients undergoing Endocrine Therapy, PRO-BETh). A major aim of PRO-BETh study is the comprehensive evaluation of adherence to treatment in pre- and post-menopausal women with breast cancer. Plasma samples of 310 breast cancer patients undergoing anti-estrogen therapy were

  2. Two Years of Adjuvant Tamoxifen Provides a Survival Benefit Compared With No Systemic Treatment in Premenopausal Patients With Primary Breast Cancer: Long-Term Follow-Up (> 25 years) of the Phase III SBII:2pre Trial.

    Science.gov (United States)

    Ekholm, Maria; Bendahl, Pär-Ola; Fernö, Mårten; Nordenskjöld, Bo; Stål, Olle; Rydén, Lisa

    2016-07-01

    The aim of this study was to evaluate the long-term effect of 2 years of adjuvant tamoxifen compared with no systemic treatment (control) in premenopausal patients with breast cancer over different time periods through long-term (> 25 years) follow-up. Premenopausal patients with primary breast cancer (N = 564) were randomly assigned to 2 years of tamoxifen (n = 276) or no systemic treatment (n = 288). Data regarding date and cause of death were obtained from the Swedish Cause of Death Register. End points were cumulative mortality (CM) and cumulative breast cancer-related mortality (CBCM). The median follow-up for the 250 patients still alive in April 2014 was 26.3 years (range, 22.7 to 29.7 years). In patients with estrogen receptor-positive tumors (n = 362), tamoxifen was associated with a marginal reduction in CM (hazard ratio [HR], 0.77; 95% CI, 0.58 to 1.03; P = .075) and a significant reduction in CBCM (HR, 0.73; 95% CI, 0.53 to 0.99; P = .046). The effect seemed to vary over time (CM years 0 to 5: HR, 1.05; 95% CI, 0.64 to 1.73; years > 5 to 15: HR, 0.58; 95% CI, 0.37 to 0.91; and after 15 years: HR, 0.82; 95% CI, 0.48 to 1.42; CBCM years 0 to 5: HR, 1.09; 95% CI, 0.65 to 1.82; years > 5 to 15: HR, 0.53; 95% CI, 0.33 to 0.86; and after 15 years: HR, 0.72; 95% CI, 0.36 to 1.44). Two years of adjuvant tamoxifen resulted in a long-term survival benefit in premenopausal patients with estrogen receptor-positive primary breast cancer. © 2016 by American Society of Clinical Oncology.

  3. Estrogen, Angiogenesis, Immunity and Cell Metabolism: Solving the Puzzle

    Directory of Open Access Journals (Sweden)

    Annalisa Trenti

    2018-03-01

    Full Text Available Estrogen plays an important role in the regulation of cardiovascular physiology and the immune system by inducing direct effects on multiple cell types including immune and vascular cells. Sex steroid hormones are implicated in cardiovascular protection, including endothelial healing in case of arterial injury and collateral vessel formation in ischemic tissue. Estrogen can exert potent modulation effects at all levels of the innate and adaptive immune systems. Their action is mediated by interaction with classical estrogen receptors (ERs, ERα and ERβ, as well as the more recently identified G-protein coupled receptor 30/G-protein estrogen receptor 1 (GPER1, via both genomic and non-genomic mechanisms. Emerging data from the literature suggest that estrogen deficiency in menopause is associated with an increased potential for an unresolved inflammatory status. In this review, we provide an overview through the puzzle pieces of how 17β-estradiol can influence the cardiovascular and immune systems.

  4. A nanomedicine based combination therapy based on QLPVM peptide functionalized liposomal tamoxifen and doxorubicin against Luminal A breast cancer.

    Science.gov (United States)

    Wang, Xiaoyou; Chen, Xianhui; Yang, Xiucong; Gao, Wei; He, Bing; Dai, Wenbing; Zhang, Hua; Wang, Xueqing; Wang, Jiancheng; Zhang, Xuan; Dai, Zhifei; Zhang, Qiang

    2016-02-01

    Though combination chemotherapy or antitumor nanomedicine is extensively investigated, their combining remains in infancy. Additionally, enhanced delivery of estrogen or its analogs to tumor with highly-expressed estrogen-receptor (ER) is seldom considered, despite its necessity for ER-positive breast cancer treatment. Here, nanomedicine based combination therapy using QLPVM conjugated liposomal tamoxifen (TAM) and doxorubicin (DOX) was designed and testified, where the penta-peptide was derived from Ku70 Bax-binding domain. Quantitative, semi-quantitative and qualitative approaches demonstrated the enhanced endocytosis and cytotoxicity of QLPVM conjugated sterically stabilized liposomes (QLPVM-SSLs) in vitro and in vivo. Mechanism studies of QLPVM excluded the possible electrostatic, hydrophobic or receptor-ligand interactions. However, as a weak cell-penetrating peptide, QLPVM significantly induced drug release from QLPVM-SSLs during their interaction with cells, which was favorable for drug internalization. These findings suggested that the nanomedicine based combination therapy using QLPVM-SSL-TAM and QLPVM-SSL-DOX might provide a rational strategy for Luminal A breast cancer. Breast cancer remains a leading cause of mortality in women worldwide. Although combined therapy using hormonal antagonist and chemotherapy is the norm nowadays, the use of these agents together in a single delivery system has not been tested. Here, the authors investigated this approach using QLPVM conjugated liposomes in in-vitro and in-vivo models. The positive findings may provide a novel direction for breast cancer treatment in the near future. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Metabolism and transport of tamoxifen in relation to its effectiveness: new perspectives on an ongoing controversy

    DEFF Research Database (Denmark)

    Cronin-Fenton, D. P.; Damkier, P.; Lash, T. L.

    2014-01-01

    Tamoxifen reduces the rate of breast cancer recurrence by approximately a half. Tamoxifen is metabolized to more active metabolites by enzymes encoded by polymorphic genes, including cytochrome P450 2D6 (CYP2D6). Tamoxifen is a substrate for ATP-binding cassette transporter proteins. We review...... is likely to be null or small, or at most moderate in subjects carrying two reduced function alleles. Future research should examine the effect of polymorphisms in genes encoding enzymes in tamoxifen's complete metabolic pathway, should comprehensively evaluate other biomarkers that affect tamoxifen...... effectiveness, such as the transport enzymes, and focus on subgroups of patients, such as premenopausal breast cancer patients, for whom tamoxifen is the only guideline endocrine therapy....

  6. 4-tert-Octylphenol stimulates the expression of cathepsins in human breast cancer cells and xenografted breast tumors of a mouse model via an estrogen receptor-mediated signaling pathway

    International Nuclear Information System (INIS)

    Lee, Hye-Rim; Choi, Kyung-Chul

    2013-01-01

    Highlights: ► Cathepsins B and D were markedly enhanced by octylphenol (OP) in MCF-7 cells. ► OP may accelerate breast cancer cell growth and cathepsins via ER-mediated signaling. ► Breast cancer cells exposed with OP to mouse model were more aggressive. ► OP can promote metastasis through the amplification of cathepsins B and D via ER-mediated signaling pathway. -- Abstract: Endocrine disrupting chemicals (EDCs) are defined as environmental compounds that modulate steroid hormone receptor-dependent responses an abnormal manner, resulting in adverse health problems for humans such as cancer growth and metastasis. Cathepsins are proteases that have been implicated in cancer progression. However, there have been few studies about the association between cathepsins and estrogenic chemicals during the cancer progression. In this study, we examined the effect(s) of 4-tert-octylphenol (OP), a potent EDC, on the expression of cathepsins B and D in human MCF-7 breast cancer cells and a xenograft mouse model. Treatment with OP significantly induced the proliferation MCF-7 cells in an MTT assay. In addition, the expression of cathepsins B and D was markedly enhanced in MCF-7 cells at both the transcriptional and the translational levels following treatment with E2 or OP up to 48 h. These results demonstrated the ability of OP to disrupt normal transcriptional regulation of cathepsins B and D in human breast cancer cells. However, the effects of OP on cell growth or overexpression of cathepsins by inhibiting ER-mediated signaling were abolished by an ER antagonist and siRNA specific for ERα. In conclusion, our findings suggest that OP at 10 −6 M, like E2, may accelerate breast cancer cell proliferation and the expression of cathepsins through an ER-mediated signaling pathway. In addition, the breast cancer cells exposed with OP to a xenograft mouse model were more aggressive according to our histological analysis and showed markedly increased expression of

  7. Tamoxifen and curcumin binding to serum albumin. Spectroscopic study

    Science.gov (United States)

    Maciążek-Jurczyk, M.; Maliszewska, M.; Pożycka, J.; Równicka-Zubik, J.; Góra, A.; Sułkowska, A.

    2013-07-01

    Tamoxifen (TMX) is widely used for the breast cancer treatment and is known as chemopreventive agent. Curcumin (CUR) is natural phenolic compound with broad spectrum of biological activity e.g. anti-inflammatory, antimicrobial, antiviral, antifungal and chemopreventive. Combination of tamoxifen and curcumin could be more effective with lower toxicity than each agent alone in use for the treatment or chemoprevention of breast cancer. Binding of drugs to serum albumin is an important factor, which determines toxicity and therapeutic dosage of the drugs. When two drugs are administered together the competition between them for the binding site on albumin can result in a decrease in bound fraction and an increase in the concentration of free biologically active fraction of drug.

  8. Tumor characteristics and survival outcomes of women with tamoxifen-related uterine carcinosarcoma.

    Science.gov (United States)

    Matsuo, Koji; Ross, Malcolm S; Bush, Stephen H; Yunokawa, Mayu; Blake, Erin A; Takano, Tadao; Ueda, Yutaka; Baba, Tsukasa; Satoh, Shinya; Shida, Masako; Ikeda, Yuji; Adachi, Sosuke; Yokoyama, Takuhei; Takekuma, Munetaka; Takeuchi, Satoshi; Nishimura, Masato; Iwasaki, Keita; Yanai, Shiori; Klobocista, Merieme M; Johnson, Marian S; Machida, Hiroko; Hasegawa, Kosei; Miyake, Takahito M; Nagano, Tadayoshi; Pejovic, Tanja; Shahzad, Mian Mk; Im, Dwight D; Omatsu, Kohei; Ueland, Frederick R; Kelley, Joseph L; Roman, Lynda D

    2017-02-01

    To examine tumor characteristics and survival outcome of women with uterine carcinosarcoma who had a history of tamoxifen use. This is a multicenter retrospective study examining stage I-IV uterine carcinosarcoma cases based on history of tamoxifen use. Patient demographics, tumor characteristics, treatment pattern, and survival outcomes were compared between tamoxifen users and non-users. Sixty-six cases of tamoxifen-related uterine carcinosarcoma were compared to 1009 cases with no history of tamoxifen use. Tamoxifen users were more likely to be older (mean age, 69 versus 64, Pcarcinosarcoma was significantly associated with a higher proportion of stage IA disease (48.4% versus 29.9%) and a lower risk of stage IVB disease (7.8% versus 16.0%) compared to tamoxifen-unrelated carcinosarcoma (P=0.034). Deep myometrial tumor invasion was less common in uterine carcinosarcoma related to tamoxifen use (28.3% versus 48.8%, P=0.002). On univariate analysis, tamoxifen use was not associated with progression-free survival (5-year rates 44.5% versus 46.8%, P=0.48) and disease-specific survival (64.0% versus 59.1%, P=0.39). After adjusting for age, past history of malignancy, stage, residual disease status at surgery, and postoperative treatment patterns, tamoxifen use was not associated with progression-free survival (adjusted-hazard ratio 0.86, 95% confidence interval 0.50 to 1.50, P=0.60) and disease-specific survival (adjusted-hazard ratio 0.68, 95% confidence interval 0.36 to 1.29, P=0.24). Our study suggests that tamoxifen-related uterine carcinosarcoma may have favorable tumor characteristics but have comparable stage-specific survival outcomes compared to tamoxifen-unrelated uterine carcinosarcoma. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. The activation of the G protein-coupled estrogen receptor (GPER) inhibits the proliferation of mouse melanoma K1735-M2 cells.

    Science.gov (United States)

    Ribeiro, Mariana P C; Santos, Armanda E; Custódio, José B A

    2017-11-01

    The activation of the G protein-coupled estrogen receptor (GPER) by its specific agonist G-1 inhibits prostate cancer and 17β-estradiol-stimulated breast cancer cell proliferation. Tamoxifen (TAM), which also activates the GPER, decreases melanoma cell proliferation, but its action mechanism remains controversial. Here we investigated the expression and the effects of GPER activation by G-1, TAM and its key metabolite endoxifen (EDX) on melanoma cells. Mouse melanoma K1735-M2 cells expressed GPER and G-1 reduced cell biomass, and the number of viable cells, without increasing cell death. Rather, G-1 decreased cell division by blocking cell cycle progression in G2. Likewise, TAM and EDX exhibited an antiproliferative activity in melanoma cells due to decreased cell division. Both G-1 and the antiestrogens showed a trend to decrease the levels of phosphorylated ERK 1/2 after 1 h treatment, although only EDX, the most potent antiproliferative antiestrogen, induced significant effects. Importantly, the targeting of GPER with siRNA abolished the cytostatic activity of both G-1 and antiestrogens, suggesting that the antitumor actions of antiestrogens in melanoma cells involve GPER activation. Our results unveil a new target for melanoma therapy and identify GPER as a key mediator of antiestrogen antiproliferative effects, which may contribute to select the patients that benefit from an antiestrogen-containing regimen. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Preliminary Genetic Imaging Study of the Association between Estrogen Receptor-α Gene Polymorphisms and Harsh Human Maternal Parenting

    OpenAIRE

    Lahey, Benjamin B.; Michalska, Kalina J.; Liu, Chunyu; Chen, Qi; Hipwell, Alison E.; Waldman, Irwin D.; Decety, Jean

    2012-01-01

    A failure of neural changes initiated by the estrogen surge in late pregnancy to reverse the valence of infant stimuli from aversive to rewarding is associated with dysfunctional maternal behavior in nonhuman mammals. Estrogen receptor-α plays the crucial role in mediating these neural effects of estrogen priming. This preliminary study examines associations between estrogen receptor-α gene polymorphisms and human maternal behavior. Two polymorphisms were associated with human negative matern...

  11. Modeling the interaction of binary and ternary mixtures of estradiol with bisphenol A and bisphenol A F in an in vitro estrogen mediated transcriptional activation assay (T47D-KBluc)

    Science.gov (United States)

    Exposure to xenoestrogens occurs against a backdrop to physiological levels of endogenous estrogens. Endogenous estrogen levels vary from low levels in early childhood to high levels during pregnancy and in young women. For example, children have circulating E2concentrations rang...

  12. Genomic agonism and phenotypic antagonism between estrogen and progesterone receptors in breast cancer.

    Science.gov (United States)

    Singhal, Hari; Greene, Marianne E; Tarulli, Gerard; Zarnke, Allison L; Bourgo, Ryan J; Laine, Muriel; Chang, Ya-Fang; Ma, Shihong; Dembo, Anna G; Raj, Ganesh V; Hickey, Theresa E; Tilley, Wayne D; Greene, Geoffrey L

    2016-06-01

    The functional role of progesterone receptor (PR) and its impact on estrogen signaling in breast cancer remain controversial. In primary ER(+) (estrogen receptor-positive)/PR(+) human tumors, we report that PR reprograms estrogen signaling as a genomic agonist and a phenotypic antagonist. In isolation, estrogen and progestin act as genomic agonists by regulating the expression of common target genes in similar directions, but at different levels. Similarly, in isolation, progestin is also a weak phenotypic agonist of estrogen action. However, in the presence of both hormones, progestin behaves as a phenotypic estrogen antagonist. PR remodels nucleosomes to noncompetitively redirect ER genomic binding to distal enhancers enriched for BRCA1 binding motifs and sites that link PR and ER/PR complexes. When both hormones are present, progestin modulates estrogen action, such that responsive transcriptomes, cellular processes, and ER/PR recruitment to genomic sites correlate with those observed with PR alone, but not ER alone. Despite this overall correlation, the transcriptome patterns modulated by dual treatment are sufficiently different from individual treatments, such that antagonism of oncogenic processes is both predicted and observed. Combination therapies using the selective PR modulator/antagonist (SPRM) CDB4124 in combination with tamoxifen elicited 70% cytotoxic tumor regression of T47D tumor xenografts, whereas individual therapies inhibited tumor growth without net regression. Our findings demonstrate that PR redirects ER chromatin binding to antagonize estrogen signaling and that SPRMs can potentiate responses to antiestrogens, suggesting that cotargeting of ER and PR in ER(+)/PR(+) breast cancers should be explored.

  13. Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens

    Science.gov (United States)

    Iwanowicz, Luke R.; Stafford, James L.; Patiño, Reynaldo; Bengten, Eva; Miller, Norman W.; Blazer, Vicki

    2014-01-01

    Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish (Ictalurus punctaus) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro. Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines.

  14. Effects of tamoxifen on neuronal morphology, connectivity and biochemistry of hypothalamic ventromedial neurons: Impact on the modulators of sexual behavior.

    Science.gov (United States)

    Sá, Susana I; Teixeira, Natércia; Fonseca, Bruno M

    2018-01-01

    Tamoxifen (TAM) is a selective estrogen receptor modulator, widely used in the treatment and prevention of estrogen-dependent breast cancer. Although with great clinical results, women on TAM therapy still report several side effects, such as sexual dysfunction, which impairs quality of life. The anatomo-functional substrates of the human sexual behavior are still unknown; however, these same substrates are very well characterized in the rodent female sexual behavior, which has advantage of being a very simple reflexive response, dependent on the activation of estrogen receptors (ERs) in the ventrolateral division of the hypothalamic ventromedial nucleus (VMNvl). In fact, in the female rodent, the sexual behavior is triggered by increasing circulation levels of estradiol that changes the nucleus neurochemistry and modulates its intricate neuronal network. Therefore, we considered of notice the examination of the possible neurochemical alterations and the synaptic plasticity impairment in VMNvl neurons of estradiol-primed female rats treated with TAM that may be in the basis of this neurological disorder. Accordingly, we used stereological and biochemical methods to study the action of TAM in axospinous and axodendritic synaptic plasticity and on ER expression. The administration of TAM changed the VMNvl neurochemistry by reducing ERα mRNA and increasing ERβ mRNA expression. Furthermore, present results show that TAM induced neuronal atrophy and reduced synaptic connectivity, favoring electrical inactivity. These data suggest that these cellular and molecular changes may be a possible neuronal mechanism of TAM action in the disruption of the VMNvl network, leading to the development of behavioral disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Estrogen receptor mRNA in mineralized tissues of rainbow trout: calcium mobilization by estrogen.

    Science.gov (United States)

    Armour, K J; Lehane, D B; Pakdel, F; Valotaire, Y; Graham, R; Russell, R G; Henderson, I W

    1997-07-07

    RT-PCR was undertaken on total RNA extracts from bone and scales of the rainbow trout, Oncorhynchus mykiss. The rainbow trout estrogen receptor (ER)-specific primers used amplified a single product of expected size from each tissue which, using Southern blotting, strongly hybridized with a 32P-labelled rtER probe under stringent conditions. These data provide the first in vivo evidence of ER mRNA in bone and scale tissues of rainbow trout and suggest that the effects of estrogen observed in this study (increased bone mineral and decreased scale mineral contents, respectively) may be mediated directly through ER.

  16. Benzophenone-1 stimulated the growth of BG-1 ovarian cancer cells by cell cycle regulation via an estrogen receptor alpha-mediated signaling pathway in cellular and xenograft mouse models

    International Nuclear Information System (INIS)

    Park, Min-Ah; Hwang, Kyung-A; Lee, Hye-Rim; Yi, Bo-Rim; Jeung, Eui-Bae; Choi, Kyung-Chul

    2013-01-01

    Highlights: ► BP-1 induced cell growth was reversed by an ER antagonist in BG-1 cells. ► BP-1 up-regulated the mRNA expression of cyclin D1. ► Up-regulation of cyclin D1 by BP-1 was reversed by an ER antagonist. ► BP-1 is a potential endocrine disruptor that exerts estrogenic effects. - Abstract: 2,4-Dihydroxybenzophenone (benzophenone-1; BP-1) is an UV stabilizer primarily used to prevent polymer degradation and deterioration in quality due to UV irradiation. Recently, BP-1 has been reported to bioaccumulate in human bodies by absorption through the skin and has the potential to induce health problems including endocrine disruption. In the present study, we examined the xenoestrogenic effect of BP-1 on BG-1 human ovarian cancer cells expressing estrogen receptors (ERs) and relevant xenografted animal models in comparison with 17-β estradiol (E2). In in vitro cell viability assay, BP-1 (10 −8 –10 −5 M) significantly increased BG-1 cell growth the way E2 did. The mechanism underlying the BG-1 cell proliferation was proved to be related with the up-regulation of cyclin D1, a cell cycle progressor, by E2 or BP-1. Both BP-1 and E2 induced cell growth and up-regulation of cyclin D1 were reversed by co-treatment with ICI 182,780, an ER antagonist, suggesting that BP-1 may mediate the cancer cell proliferation via an ER-dependent pathway like E2. On the other hand, the expression of p21, a regulator of cell cycle progression at G 1 phase, was not altered by BP-1 though it was down-regulated by E2. In xenograft mouse models transplanted with BG-1 cells, BP-1 or E2 treatment significantly increased the tumor mass formation compared to a vehicle (corn oil) within 8 weeks. In histopathological analysis, the tumor sections of E2 or BP-1 group displayed extensive cell formations with high density and disordered arrangement, which were supported by the increased number of BrdUrd positive nuclei and the over-expression of cyclin D1 protein. Taken together, these

  17. The estrogen-dependent baroreflex dysfunction caused by nicotine in female rats is mediated via NOS/HO inhibition: Role of sGC/PI3K/MAPKERK

    International Nuclear Information System (INIS)

    Fouda, Mohamed A.; El-Gowelli, Hanan M.; El-Gowilly, Sahar M.; El-Mas, Mahmoud M.

    2015-01-01

    We have previously reported that estrogen (E2) exacerbates the depressant effect of chronic nicotine on arterial baroreceptor activity in female rats. Here, we tested the hypothesis that this nicotine effect is modulated by nitric oxide synthase (NOS) and/or heme oxygenase (HO) and their downstream soluble guanylate cyclase (sGC)/phosphatidylinositol 3-kinase (PI3K)/mitogen-activated protein kinases (MAPKs) signaling. We investigated the effects of (i) inhibition or facilitation of NOS or HO on the interaction of nicotine (2 mg/kg/day i.p., 2 weeks) with reflex bradycardic responses to phenylephrine in ovariectomized (OVX) rats treated with E2 or vehicle, and (ii) central pharmacologic inhibition of sGC, PI3K, or MAPKs on the interaction. The data showed that the attenuation by nicotine of reflex bradycardia in OVXE2 rats was abolished after treatment with hemin (HO inducer) or L-arginine (NOS substrate). The hemin or L-arginine effect disappeared after inhibition of NOS (Nω-Nitro-L-arginine methyl ester hydrochloride, L-NAME) and HO (zinc protoporphyrin IX, ZnPP), respectively, denoting the interaction between the two enzymatic pathways. E2-receptor blockade (ICI 182,780) reduced baroreflexes in OVXE2 rats but had no effect on baroreflex improvement induced by hemin or L-arginine. Moreover, baroreflex enhancement by hemin was eliminated following intracisternal (i.c.) administration of wortmannin, ODQ, or PD98059 (inhibitors of PI3K, sGC, and extracellular signal-regulated kinases, MAPK ERK , respectively). In contrast, the hemin effect was preserved after inhibition of MAPK p38 (SB203580) or MAPK JNK (SP600125). Overall, NOS/HO interruption underlies baroreflex dysfunction caused by nicotine in female rats and the facilitation of NOS/HO-coupled sGC/PI3K/MAPK ERK signaling might rectify the nicotine effect. - Highlights: • Hemin or L-arginine blunts baroreflex dysfunction caused by nicotine in OVXE2 rats. • NO/CO crosstalk mediates favorable baroreflex effect

  18. Adjuvant Tamoxifen Plus Ovarian Function Suppression Versus Tamoxifen Alone in Premenopausal Women With Early Breast Cancer: Patient-Reported Outcomes in the Suppression of Ovarian Function Trial

    Science.gov (United States)

    Luo, Weixiu; Bernhard, Jürg; Francis, Prudence A.; Burstein, Harold J.; Ciruelos, Eva; Bellet, Meritxell; Pavesi, Lorenzo; Lluch, Ana; Visini, Marilena; Parmar, Vani; Tondini, Carlo; Kerbrat, Pierre; Perelló, Antonia; Neven, Patrick; Torres, Roberto; Lombardi, Davide; Puglisi, Fabio; Karlsson, Per; Ruhstaller, Thomas; Colleoni, Marco; Coates, Alan S.; Goldhirsch, Aron; Price, Karen N.; Gelber, Richard D.; Regan, Meredith M.; Fleming, Gini F.

    2016-01-01

    Purpose The Suppression of Ovarian Function trial showed improved disease control for tamoxifen plus ovarian function suppression (OFS) compared with tamoxifen alone for the cohort of premenopausal patients who received prior chemotherapy. We present the patient-reported outcomes. Patients and Methods The quality-of-life (QoL) analysis includes 1,722 of 2,045 premenopausal patients with hormone receptor–positive breast cancer randomly assigned to receive adjuvant treatment with 5 years of tamoxifen plus OFS or tamoxifen alone. Chemotherapy use before enrollment was optional. Patients completed a QoL form consisting of global and symptom indicators at baseline, every 6 months for 24 months, and annually during years 3 to 6. Differences in the change of QoL from baseline between the two treatments were tested at 6, 24, and 60 months with mixed models for repeated measures with and without chemotherapy and overall. Results Patients on tamoxifen plus OFS were more affected than patients on tamoxifen alone by hot flushes at 6 and 24 months, by loss of sexual interest and sleep disturbance at 6 months, and by vaginal dryness up to 60 months. Without prior chemotherapy, patients on tamoxifen alone reported more vaginal discharge over the 5 years than patients on tamoxifen plus OFS. Symptom-specific treatment differences at 6 months were less pronounced in patients with prior chemotherapy. Changes in global QoL indicators from baseline were small and similar between treatments over the whole treatment period. Conclusion Overall, OFS added to tamoxifen resulted in worse endocrine symptoms and sexual functioning during the first 2 years of treatment, with variable magnitudes of treatment differences. Short-term differences in symptom-specific QoL, treatment burden, and coping effort between treatment groups were less pronounced for patients with prior chemotherapy, the cohort that benefited most from OFS in terms of disease control. PMID:27022111

  19. Monitoring mammary tumor progression and effect of tamoxifen treatment in MMTV-PymT using MRI and magnetic resonance spectroscopy with hyperpolarized [1-13C]pyruvate

    DEFF Research Database (Denmark)

    Asghar Butt, Sadia; Søgaard, Lise V.; Ardenkjær-Larsen, Jan Henrik

    2015-01-01

    Purpose: To use dynamic magnetic resonance spectroscopy (MRS) of hyperpolarized 13C-pyruvate to follow the progress over time in vivo of breast cancer metabolism in the MMTV-PymT model, and to follow the response to the anti-estrogen drug tamoxifen. Methods: Tumor growth was monitored by anatomical...... significantly in the treated group. Conclusion: These hyperpolarized 13C MRS findings indicate that tumor metabolic changes affects kP. The measured kp did not relate to treatment response to the same extent as did tumor growth, histological evaluation, and in vitro determination of LDH activity. © 2014 Wiley...

  20. Estrogen receptor alpha deletion enhances the metastatic phenotype of Ron overexpressing mammary tumors in mice

    Directory of Open Access Journals (Sweden)

    Marshall Aaron M

    2012-01-01

    Full Text Available Abstract Background The receptor tyrosine kinase family includes many transmembrane proteins with diverse physiological and pathophysiological functions. The involvement of tyrosine kinase signaling in promoting a more aggressive tumor phenotype within the context of chemotherapeutic evasion is gaining recognition. The Ron receptor is a tyrosine kinase receptor that has been implicated in the progression of breast cancer and evasion of tamoxifen therapy. Results Here, we report that Ron expression is correlated with in situ, estrogen receptor alpha (ERα-positive tumors, and is higher in breast tumors following neoadjuvant tamoxifen therapy. We also demonstrate that the majority of mammary tumors isolated from transgenic mice with mammary specific-Ron overexpression (MMTV-Ron mice, exhibit appreciable ER expression. Moreover, genetic-ablation of ERα, in the context of Ron overexpression, leads to delayed mammary tumor initiation and growth, but also results in an increased metastasis. Conclusions Ron receptor overexpression is associated with ERα-positive human and murine breast tumors. In addition, loss of ERα on a Ron overexpressing background in mice leads to the development of breast tumors which grow slower but which exhibit more metastasis and suggests that targeting of ERα, as in the case of tamoxifen therapy, may reduce the growth of Ron overexpressing breast cancers but may cause these tumors to be more metastatic.

  1. Functional adaptation in female rats: the role of estrogen signaling.

    Directory of Open Access Journals (Sweden)

    Susannah J Sample

    Full Text Available Sex steroids have direct effects on the skeleton. Estrogen acts on the skeleton via the classical genomic estrogen receptors alpha and beta (ERα and ERβ, a membrane ER, and the non-genomic G-protein coupled estrogen receptor (GPER. GPER is distributed throughout the nervous system, but little is known about its effects on bone. In male rats, adaptation to loading is neuronally regulated, but this has not been studied in females.We used the rat ulna end-loading model to induce an adaptive modeling response in ovariectomized (OVX female Sprague-Dawley rats. Rats were treated with a placebo, estrogen (17β-estradiol, or G-1, a GPER-specific agonist. Fourteen days after OVX, rats underwent unilateral cyclic loading of the right ulna; half of the rats in each group had brachial plexus anesthesia (BPA of the loaded limb before loading. Ten days after loading, serum estrogen concentrations, dorsal root ganglion (DRG gene expression of ERα, ERβ, GPER, CGRPα, TRPV1, TRPV4 and TRPA1, and load-induced skeletal responses were quantified. We hypothesized that estrogen and G-1 treatment would influence skeletal responses to cyclic loading through a neuronal mechanism. We found that estrogen suppresses periosteal bone formation in female rats. This physiological effect is not GPER-mediated. We also found that absolute mechanosensitivity in female rats was decreased, when compared with male rats. Blocking of adaptive bone formation by BPA in Placebo OVX females was reduced.Estrogen acts to decrease periosteal bone formation in female rats in vivo. This effect is not GPER-mediated. Gender differences in absolute bone mechanosensitivity exist in young Sprague-Dawley rats with reduced mechanosensitivity in females, although underlying bone formation rate associated with growth likely influences this observation. In contrast to female and male rats, central neuronal signals had a diminished effect on adaptive bone formation in estrogen-deficient female rats.

  2. Synthesis and biological evaluation of guanylhydrazone coactivator binding inhibitors for the estrogen receptor.

    Science.gov (United States)

    LaFrate, Andrew L; Gunther, Jillian R; Carlson, Kathryn E; Katzenellenbogen, John A

    2008-12-01

    Most patients with hormone-responsive breast cancer eventually develop resistance to traditional antiestrogens such as tamoxifen, and this has become a major obstacle in their treatment. We prepared and characterized the activity of a series of 16 guanylhydrazone small molecules that are designed to block estrogen receptor (ER) activity through a non-traditional mechanism, by directly interfering with coactivator binding to agonist-liganded ER. The inhibitory activity of these compounds was determined in cell-based transcription assays using ER-responsive reporter gene and mammalian two-hybrid assays. Several of the compounds gave IC(50) values in the low micromolar range. Two secondary assays were used to confirm that these compounds were acting through the proposed non-traditional mode of estrogen inhibitory action and not as conventional antagonists at the ligand binding site.

  3. Mechanisms of the hepatoprotective effects of tamoxifen against drug-induced and chemical-induced acute liver injuries

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Yukitaka; Miyashita, Taishi; Higuchi, Satonori [Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920‐1192 (Japan); Tsuneyama, Koichi [Department of Diagnostic Pathology, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Sugitani, Toyama 930‐0194 (Japan); Endo, Shinya [Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920‐1192 (Japan); Tsukui, Tohru [Research Center for Genomic Medicine, Saitama Medical University, Yamane, Hidaka 350‐1241 (Japan); Toyoda, Yasuyuki; Fukami, Tatsuki; Nakajima, Miki [Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920‐1192 (Japan); Yokoi, Tsuyoshi, E-mail: tyokoi@p.kanazawa-u.ac.jp [Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920‐1192 (Japan)

    2012-10-01

    Although estrogen receptor (ER)α agonists, such as estradiol and ethinylestradiol (EE2), cause cholestasis in mice, they also reduce the degree of liver injury caused by hepatotoxicants as well as ischemia–reperfusion. The functional mechanisms of ERα have yet to be elucidated in drug-induced or chemical-induced liver injury. The present study investigated the effects of an ERα agonist, selective ER modulators (SERMs) and an ER antagonist on drug-induced and chemical-induced liver injuries caused by acetaminophen, bromobenzene, diclofenac, and thioacetamide (TA). We observed hepatoprotective effects of EE2, tamoxifen (TAM) and raloxifene pretreatment in female mice that were exposed to a variety of hepatotoxic compounds. In contrast, the ER antagonist did not show any hepatoprotective effects. DNA microarray analyses suggested that monocyte to macrophage differentiation-associated 2 (Mmd2) protein, which has an unknown function, is commonly increased by TAM and RAL pretreatment, but not by pretreatment with the ER antagonist. In ERα-knockout mice, the hepatoprotective effects of TAM and the increased expression of Mmd2 mRNA were not observed in TA-induced liver injury. To investigate the function of Mmd2, the expression level of Mmd2 mRNA was significantly knocked down to approximately 30% in mice by injection of siRNA for Mmd2 (siMmd2). Mmd2 knockdown resulted in a reduction of the protective effects of TAM on TA-induced liver injury in mice. This is the first report of the involvement of ERα in drug-induced or chemical-induced liver injury. Upregulation of Mmd2 protein in the liver was suggested as the mechanism of the hepatoprotective effects of EE2 and SERMs. -- Highlights: ► Liver injury induced by drugs or chemicals was investigated in mice. ► Liver injury was suppressed by pretreatment with tamoxifen in female mice. ► Mmd2, whose function was unknown, could be a candidate gene for liver protection. ► Tamoxifen up-regulated Mmd2 mRNA expression

  4. Mechanisms of the hepatoprotective effects of tamoxifen against drug-induced and chemical-induced acute liver injuries

    International Nuclear Information System (INIS)

    Yoshikawa, Yukitaka; Miyashita, Taishi; Higuchi, Satonori; Tsuneyama, Koichi; Endo, Shinya; Tsukui, Tohru; Toyoda, Yasuyuki; Fukami, Tatsuki; Nakajima, Miki; Yokoi, Tsuyoshi

    2012-01-01

    Although estrogen receptor (ER)α agonists, such as estradiol and ethinylestradiol (EE2), cause cholestasis in mice, they also reduce the degree of liver injury caused by hepatotoxicants as well as ischemia–reperfusion. The functional mechanisms of ERα have yet to be elucidated in drug-induced or chemical-induced liver injury. The present study investigated the effects of an ERα agonist, selective ER modulators (SERMs) and an ER antagonist on drug-induced and chemical-induced liver injuries caused by acetaminophen, bromobenzene, diclofenac, and thioacetamide (TA). We observed hepatoprotective effects of EE2, tamoxifen (TAM) and raloxifene pretreatment in female mice that were exposed to a variety of hepatotoxic compounds. In contrast, the ER antagonist did not show any hepatoprotective effects. DNA microarray analyses suggested that monocyte to macrophage differentiation-associated 2 (Mmd2) protein, which has an unknown function, is commonly increased by TAM and RAL pretreatment, but not by pretreatment with the ER antagonist. In ERα-knockout mice, the hepatoprotective effects of TAM and the increased expression of Mmd2 mRNA were not observed in TA-induced liver injury. To investigate the function of Mmd2, the expression level of Mmd2 mRNA was significantly knocked down to approximately 30% in mice by injection of siRNA for Mmd2 (siMmd2). Mmd2 knockdown resulted in a reduction of the protective effects of TAM on TA-induced liver injury in mice. This is the first report of the involvement of ERα in drug-induced or chemical-induced liver injury. Upregulation of Mmd2 protein in the liver was suggested as the mechanism of the hepatoprotective effects of EE2 and SERMs. -- Highlights: ► Liver injury induced by drugs or chemicals was investigated in mice. ► Liver injury was suppressed by pretreatment with tamoxifen in female mice. ► Mmd2, whose function was unknown, could be a candidate gene for liver protection. ► Tamoxifen up-regulated Mmd2 mRNA expression

  5. Tamoxifen for one year versus two years versus 6 months of Tamoxifen and 6 months of megestrol acetate: A randomized comparison in postmenopausal patients with high-risk breast cancer (DBCG 89C)

    DEFF Research Database (Denmark)

    Andersen, Jørn; Kamby, C.; Ejlertsen, B.

    2008-01-01

    From January 1, 1990 to December 31, 1994, DBCG conducted a randomised trial in 1 615 postmenopausal women with operable, high-risk, receptor-positive or -unknown breast cancer. The patients were after surgery randomised to Tamoxifen for 1 year (TAM1), Tamoxifen for 2 years (TAM 2) or Tamoxifen...

  6. High CDK6 protects cells from fulvestrant-mediated apoptosis and is a predictor of resistance to fulvestrant in estrogen receptor-positive metastatic breast cancer

    DEFF Research Database (Denmark)

    Alves, Carla Maria Lourenco; Elias, Daniel; Lyng, Maria B

    2016-01-01

    in cell proliferation, apoptosis and kinase activity. Furthermore, we evaluated CDK6 expression in metastatic samples from breast cancer patients treated or not with fulvestrant. RESULTS: We found increased expression of CDK6 in two fulvestrant-resistant cell models vs. sensitive cells. Reduction of CDK6...... expression impaired fulvestrant-resistant cell growth and induced apoptosis. Treatment with palbociclib re-sensitized fulvestrant-resistant cells to fulvestrant through alteration of retinoblastoma protein phosphorylation. High CDK6 levels in metastatic samples from two independent cohorts of breast cancer.......511, respectively). CONCLUSIONS: Our results indicate that upregulation of CDK6 may be an important mechanism in overcoming fulvestrant-mediated growth inhibition in breast cancer cells. Patients with advanced ER+ breast cancer exhibiting high CDK6 expression in the metastatic lesions show shorter PFS upon...

  7. Role of estrogen replacement therapy in memory enhancement and the prevention of neuronal loss associated with Alzheimer's disease.

    Science.gov (United States)

    Simpkins, J W; Green, P S; Gridley, K E; Singh, M; de Fiebre, N C; Rajakumar, G

    1997-09-22

    cells from the neurotoxic effects of serum deprivation and hypoglycemia in human neuroblastoma cell lines. We have also observed that 17-alpha-estradiol (alpha-E2), a weak estrogen, shows neuroprotective efficacy in the SK-N-SH cell line at concentrations equivalent to beta-E2. Finally, we have observed that tamoxifen, a classic estrogen antagonist, blocks only one-third of the neuroprotective effects of either alpha-E2 or beta-E2. Collectively, these results indicate that estrogen is behaviorally active in tests of learning/ memory; activates basal forebrain cholinergic neurons and neurotrophin expression; and is neuroprotective for human neuronal cultures. We conclude that estrogen may be a useful therapy for AD and other neurodegenerative diseases.

  8. CYP2D6 genotype and tamoxifen response in postmenopausal women with endocrine-responsive breast cancer

    DEFF Research Database (Denmark)

    Regan, Meredith M; Leyland-Jones, Brian; Bouzyk, Mark

    2012-01-01

    Adjuvant tamoxifen therapy is effective for postmenopausal women with endocrine-responsive breast cancer. Cytochrome P450 2D6 (CYP2D6) enzyme metabolizes tamoxifen to clinically active metabolites, and CYP2D6 polymorphisms may adversely affect tamoxifen efficacy. In this study, we investigated...

  9. Non-adherence to the Use of Tamoxifen in the First year by the ...

    African Journals Online (AJOL)

    Non-adherence to the Use of Tamoxifen in the First year by the Breast Cancer Patients in an African Population. ... study was to determine the rate and contributory factors to non adherence rate to tamoxifen during the first year of usage in patients with breast cancer in LAUTECH teaching hospital (LTH) Osogbo , Nigeria .

  10. LAMP3 is involved in tamoxifen resistance in breast cancer cells through the modulation of autophagy

    NARCIS (Netherlands)

    A. Nagelkerke (Anika); A.M. Sieuwerts (Anieta); J. Bussink (Johan); F.C. Sweep (Fred); M.P. Look (Maxime); J.A. Foekens (John); J.W.M. Martens (John); P.N. Span (Paul)

    2014-01-01

    textabstractLysosome-associated membrane protein 3 (LAMP3) is a member of the LAMP-family of proteins, which are involved in the process of autophagy. Autophagy is induced by tamoxifen in breast cancer cells and may contribute to tamoxifen resistance. In this study, the significance of LAMP3 for

  11. Effect of tamoxifen on the endometrium and the menstrual cycle of premenopausal breast cancer patients

    NARCIS (Netherlands)

    Buijs, Ciska; Willemse, Pax H. B.; de Vries, E. G. E.; Ten Hoor, Klase A.; Boezen, H. M.; Hollema, Harry; Mourits, Marian J. E.

    OBJECTIVE: Tamoxifen, a nonsteroidal antiestrogen, is the agent of choice in the treatment of premenopausal receptor-positive breast cancer. This study aimed to investigate the influence of tamoxifen on the menstrual cycle and serum hormone levels and the subsequent endometrial response in

  12. Tamoxifen and Risk of Contralateral Breast Cancer for BRCA1 and BRCA2 Mutation Carriers

    DEFF Research Database (Denmark)

    Phillips, Kelly-Anne; Milne, Roger L; Rookus, Matti A

    2013-01-01

    To determine whether adjuvant tamoxifen treatment for breast cancer (BC) is associated with reduced contralateral breast cancer (CBC) risk for BRCA1 and/or BRCA2 mutation carriers.......To determine whether adjuvant tamoxifen treatment for breast cancer (BC) is associated with reduced contralateral breast cancer (CBC) risk for BRCA1 and/or BRCA2 mutation carriers....

  13. Tamoxifen therapy for the management of pubertal gynecomastia: a systematic review

    NARCIS (Netherlands)

    Lapid, Oren; van Wingerden, Jan J.; Perlemuter, Leon

    2013-01-01

    Objective: A systematic review to assess the efficacy of tamoxifen in the management of idiopathic pubertal gynecomastia. Data sources: Searches were conducted using the databases of Medline (search engine PubMed) and Web of Science (R). Study selection: Studies reporting the use of Tamoxifen for

  14. Letrozole therapy alone or in sequence with tamoxifen in women with breast cancer

    DEFF Research Database (Denmark)

    Mouridsen, H.; Giobbie-Hurder, A.; Goldhirsch, A.

    2009-01-01

    with tamoxifen (hazard ratio for letrozole, 0.87; 95% CI, 0.75 to 1.02; P=0.08). The rate of adverse events was as expected on the basis of previous reports of letrozole and tamoxifen therapy. CONCLUSIONS: Among postmenopausal women with endocrine-responsive breast cancer, sequential treatment with letrozole...

  15. Mitotically Active Leiomyoma of the Uterus in a Postmenopausal Breast Cancer Patient Receiving Tamoxifen

    Directory of Open Access Journals (Sweden)

    I-Feng Liu

    2006-06-01

    Conclusion: Endometrial cancer is rarely noted in breast cancer patients taking tamoxifen. Further, none have reported mitotically active leiomyoma of the uterus. From this case, endometrial proliferation and mitotically active leiomyoma of the uterus may be related to tamoxifen therapy, and should not be neglected in breast cancer patients.

  16. Risk and prognosis of endometrial cancer after tamoxifen for breast cancer

    NARCIS (Netherlands)

    Bergman, L; Beelen, MLR; Gallee, MPW; Hollema, H; Benraadt, J; van Leeuwen, FE

    2000-01-01

    Background Tamoxifen increases the risk of endometrial cancer. However, few studies have produced reliable risk estimates by duration, dose, and recency of use, or addressed the prognosis of endometrial cancers in tamoxifen-treated women. Methods We did a nationwide case-control study on the risk

  17. Estrogenic effects of marijuana smoke condensate and cannabinoid compounds

    International Nuclear Information System (INIS)

    Lee, Soo Yeun; Oh, Seung Min; Chung, Kyu Hyuck

    2006-01-01

    Chronic exposure to marijuana produces adverse effects on the endocrine and reproductive systems in humans; however, the experimental evidence for this presented thus far has not been without controversy. In this study, the estrogenic effect of marijuana smoke condensate (MSC) was evaluated using in vitro bioassays, viz., the cell proliferation assay, the reporter gene assay, and the ER competitive binding assay. The results of these assays were compared with those of three major cannabinoids, i.e., THC, CBD, and CBN. The estrogenic effect of MSC was further confirmed by the immature female rat uterotrophic assay. MSC stimulated the estrogenicity related to the ER-mediated pathway, while neither THC, CBD, nor CBN did. Moreover, treatment with 10 and 25 mg/kg MSC induced significant uterine response, and 10 mg/kg MSC resulted in an obvious change in the uterine epithelial cell appearance. MSC also enhanced the IGFBP-1 gene expression in a dose-dependent manner. To identify the constituents of MSC responsible for its estrogenicity, the MSC fractionated samples were examined using another cell proliferation assay, and the estrogenic active fraction was analyzed using GC-MS. In the organic acid fraction that showed the strongest estrogenic activity among the seven fractions of MSC, phenols were identified. Our results suggest that marijuana abuse is considered an endocrine-disrupting factor. Furthermore, these results suggest that the phenolic compounds contained in MSC play a role in its estrogenic effect

  18. Poly(amidoamine-Cholesterol Conjugate Nanoparticles Obtained by Electrospraying as Novel Tamoxifen Delivery System

    Directory of Open Access Journals (Sweden)

    R. Cavalli

    2011-01-01

    Full Text Available A new poly(amidoamine-cholesterol (PAA-cholesterol conjugate was synthesized, characterized and used to produce nanoparticles by the electrospraying technique. The electrospraying is a method of liquid atomization that consists in the dispersion of a solution into small charged droplets by an electric field. Tuning the electrospraying process parameters spherical PAA-chol nanoparticles formed. The PAA-cholesterol nanoparticles showed sizes lower than 500 nm and spherical shape. The drug incorporation capacity was investigated using tamoxifen, a lipophilic anticancer drug, as model drug. The incorporation of the tamoxifen did not affect the shape and sizes of nanoparticles showing a drug loading of 40%. Tamoxifen-loaded nanoparticles exhibited a higher dose-dependent cytotoxicity than free tamoxifen, while blank nanoparticles did not show any cytotoxic effect at the same concentrations. The electrospray technique might be proposed to produce tamoxifen-loaded PAA-chol nanoparticle in powder form without any excipient in a single step.

  19. Risk of skin cancer following tamoxifen treatment in more than 16,000 breast cancer patients

    DEFF Research Database (Denmark)

    Præstegaard, Camilla; Kjaer, Susanne K.; Andersson, Michael

    2016-01-01

    diagnosed with breast cancer during 1977–2007 from the nationwide clinical database of the Danish Breast Cancer Cooperative Group, was followed for a primary skin cancer [basal cell carcinoma (BCC), squamous cell carcinoma (SCC) or melanoma] in the Danish Cancer Registry supplemented by data on BCC and SCC......Background: Women with breast cancer are at increased risk of developing skin cancer. Little is known about how tamoxifen affects this risk. We aimed to investigate whether tamoxifen treatment following breast cancer is associated with skin cancer. Methods: A cohort consisting of 44,589 women...... from the Danish Pathology Register. We investigated incidence of skin cancer among 16,214 women treated with tamoxifen compared to 28,375 women not treated with tamoxifen by calculating incidence rate ratios (IRRs) in Cox regression models. Results: Tamoxifen users were followed for a median of 2...

  20. The Prescription Pattern of Chinese Herbal Products Containing Ginseng among Tamoxifen-Treated Female Breast Cancer Survivors in Taiwan: A Population-Based Study

    Directory of Open Access Journals (Sweden)

    Wei-Lung Hsu

    2015-01-01

    Full Text Available Background. The purpose of our study is to analyze the association between prescribed Chinese herbal products (CHPs containing Ginseng and the risk of endometrial cancer among tamoxifen (TMX users and to identify any possible interactive effects between Ginseng and TMX with respect to preventing the development of subsequent endometrial cancer in an estrogen-dependent breast cancer population in Taiwan. Methods. All patients newly diagnosed with invasive breast cancer receiving tamoxifen treatment from January 1, 1998, to December 31, 2008, were selected from the National Health Insurance Research Database. The usage, frequency of service, and CHP-Ginseng prescribed across the 30,556 TMX-treated breast cancer (BC survivors were evaluated. Logistic regression was employed to estimate the odds ratios (ORs for the utilization of CHP-Ginseng. Cox’s proportional hazard regression was performed to calculate the hazard ratios (HRs for endometrial cancer associated with Ginseng use among the TMX-treated BC cohort. Results. The HR for the development of endometrial cancer among breast cancer survivors who had ever taken Ginseng after TXM treatment was significantly decreased compared to those who never used CHP. Conclusion. A significant inhibitory relationship between Ginseng consumption and subsequent endometrial cancer less than 2 years after TMX treatment was detected among BC survivors.

  1. Selective Estrogen Receptor Modulators regulate reactive microglia after penetrating brain injury

    Directory of Open Access Journals (Sweden)

    George E. Barreto

    2014-06-01

    Full Text Available Following brain injury, microglia assume a reactive-like state and secrete pro-inflammatory molecules that can potentiate damage. A therapeutic strategy that may limit microgliosis is of potential interest. In this context, selective estrogen receptor modulators, such as raloxifene and tamoxifen, are known to reduce microglia activation induced by neuroinflammatory stimuli in young animals. In the present study, we have assessed whether raloxifene and tamoxifen are able to affect microglia activation after brain injury in young and aged animals in time points relevant to clinics, which is hours after brain trauma. Volume fraction of MHC-II+ microglia was estimated according to the point-counting method of Weibel within a distance of 350 μm from the lateral border of the wound, and cellular morphology was measured by fractal analysis. Two groups of animals were studied: 1 young rats, ovariectomized at 2 months of age; and 2 aged rats, ovariectomized at 18 months of age. Fifteen days after ovariectomy animals received a stab wound brain injury and the treatment with estrogenic compounds. Our findings indicate that raloxifene and tamoxifen reduced microglia activation in both young and aged animals. Although the volume fraction of reactive microglia was found lower in aged animals, this was accompanied by important changes in cell morphology, where aged microglia assume a bushier and hyperplasic aspect when compared to young microglia. These data suggest that early regulation of microglia activation provides a mechanism by which SERMs may exert a neuroprotective effect in the setting of a brain trauma.

  2. Estrogen Effects on Wound Healing.

    Science.gov (United States)

    Horng, Huann-Cheng; Chang, Wen-Hsun; Yeh, Chang-Ching; Huang, Ben-Shian; Chang, Chia-Pei; Chen, Yi-Jen; Tsui, Kuan-Hao; Wang, Peng-Hui

    2017-11-03

    Wound healing is a physiological process, involving three successive and overlapping phases-hemostasis/inflammation, proliferation, and remodeling-to maintain the integrity of skin after trauma, either by accident or by procedure. Any disruption or unbalanced distribution of these processes might result in abnormal wound healing. Many molecular and clinical data support the effects of estrogen on normal skin homeostasis and wound healing. Estrogen deficiency, for example in postmenopausal women, is detrimental to wound healing processes, notably inflammation and re-granulation, while exogenous estrogen treatment may reverse these effects. Understanding the role of estrogen on skin might provide further opportunities to develop estrogen-related therapy for assistance in wound healing.

  3. Estrogens, Neuroinflammation, and Neurodegeneration

    Science.gov (United States)

    Villa, Alessandro; Vegeto, Elisabetta; Poletti, Angelo

    2016-01-01

    Inflammatory activation of microglia is a hallmark of several disorders of the central nervous system. In addition to protecting the brain against inflammatory insults, microglia are neuroprotective and play a significant role in maintaining neuronal connectivity, but the prolongation of an inflammatory status may limit the beneficial functions of these immune cells. The finding that estrogen receptors are present in monocyte-derived cells and that estrogens prevent and control the inflammatory response raise the question of the role that this sex steroid plays in the manifestation and progression of pathologies that have a clear sex difference in prevalence, such as multiple sclerosis, Parkinson's disease, and Alzheimer's disease. The present review aims to provide a critical review of the current literature on the actions of estrogen in microglia and on the involvement of estrogen receptors in the manifestation of selected neurological disorders. This current understanding highlights a research area that should be expanded to identify appropriate replacement therapies to slow the progression of such diseases. PMID:27196727

  4. Anaerobic biotransformation of estrogens

    International Nuclear Information System (INIS)

    Czajka, Cynthia P.; Londry, Kathleen L.

    2006-01-01

    Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-α-ethynylestradiol (EE2) and 17-β-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 μg L -1 day -1 ), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-α-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-α-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments

  5. Anaerobic biotransformation of estrogens

    Energy Technology Data Exchange (ETDEWEB)

    Czajka, Cynthia P. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Londry, Kathleen L. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada)]. E-mail: londryk@cc.umanitoba.ca

    2006-08-31

    Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-{alpha}-ethynylestradiol (EE2) and 17-{beta}-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 {mu}g L{sup -1} day{sup -1}), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-{alpha}-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-{alpha}-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments.

  6. Mediatization

    DEFF Research Database (Denmark)

    Hjarvard, Stig

    2017-01-01

    Mediatization research shares media effects studies' ambition of answering the difficult questions with regard to whether and how media matter and influence contemporary culture and society. The two approaches nevertheless differ fundamentally in that mediatization research seeks answers...... research is concerned with long-term structural changes involving media, culture, and society, i.e. the influences of the media are understood in relation to how media are implicated in social and cultural changes and how these processes come to create new conditions for human communication and interaction....... From the perspective of mediatization research, the most important effect of the media stems from their embeddedness in culture and society....

  7. Molecular Docking and 3D-Pharmacophore Modeling to Study the Interactions of Chalcone Derivatives with Estrogen Receptor Alpha

    Directory of Open Access Journals (Sweden)

    Muchtaridi Muchtaridi

    2017-10-01

    Full Text Available Tamoxifen is the most frequently used anti-estrogen adjuvant treatment for estrogen receptor-positive breast cancer. However, it is associated with an increased risk of several serious side–effects, such as uterine cancer, stroke, and pulmonary embolism. The 2′,4′-dihydroxy-6-methoxy-3,5-dimethylchalcone (ChalcEA from plant leaves of Eugenia aquea, has been found to inhibit the proliferation of MCF-7 human breast cancer cells in a dose-dependent manner, with an IC50 of 74.5 μg/mL (250 μM. The aim of this work was to study the molecular interactions of new ChalcEA derivatives formed with the Estrogen Receptor α (ERα using computer aided drug design approaches. Molecular docking using Autodock 4.2 was employed to explore the modes of binding of ChalcEA derivatives with ERα. The 3D structure-based pharmacophore model was derived using LigandScout 4.1 Advanced to investigate the important chemical interactions of the ERα-tamoxifen complex structure. The binding energy and the tamoxifen-pharmacophore fit score of the best ChalcEA derivative (HNS10 were −12.33 kcal/mol and 67.07 kcal/mol, respectively. The HNS10 interacted with Leu346, Thr347, Leu349, Ala350, Glu353, Leu387, Met388, Leu391, Arg394, Met421, and Leu525. These results suggest that the new ChalcEA derivatives could serve as the lead compound for potent ERα inhibitor in the fight against breast cancer.

  8. Molecular Docking and 3D-Pharmacophore Modeling to Study the Interactions of Chalcone Derivatives with Estrogen Receptor Alpha.

    Science.gov (United States)

    Muchtaridi, Muchtaridi; Syahidah, Hasna Nur; Subarnas, Anas; Yusuf, Muhammad; Bryant, Sharon D; Langer, Thierry

    2017-10-16

    Tamoxifen is the most frequently used anti-estrogen adjuvant treatment for estrogen receptor-positive breast cancer. However, it is associated with an increased risk of several serious side-effects, such as uterine cancer, stroke, and pulmonary embolism. The 2',4'-dihydroxy-6-methoxy-3,5-dimethylchalcone (ChalcEA) from plant leaves of Eugenia aquea , has been found to inhibit the proliferation of MCF-7 human breast cancer cells in a dose-dependent manner, with an IC 50 of 74.5 μg/mL (250 μM). The aim of this work was to study the molecular interactions of new ChalcEA derivatives formed with the Estrogen Receptor α (ERα) using computer aided drug design approaches. Molecular docking using Autodock 4.2 was employed to explore the modes of binding of ChalcEA derivatives with ERα. The 3D structure-based pharmacophore model was derived using LigandScout 4.1 Advanced to investigate the important chemical interactions of the ERα-tamoxifen complex structure. The binding energy and the tamoxifen-pharmacophore fit score of the best ChalcEA derivative (HNS10) were -12.33 kcal/mol and 67.07 kcal/mol, respectively. The HNS10 interacted with Leu346, Thr347, Leu349, Ala350, Glu353, Leu387, Met388, Leu391, Arg394, Met421, and Leu525. These results suggest that the new ChalcEA derivatives could serve as the lead compound for potent ERα inhibitor in the fight against breast cancer.

  9. Linc-RoR promotes MAPK/ERK signaling and confers estrogen-independent growth of breast cancer.

    Science.gov (United States)

    Peng, Wan-Xin; Huang, Jian-Guo; Yang, Liu; Gong, Ai-Hua; Mo, Yin-Yuan

    2017-10-17

    The conversion from estrogen-dependent to estrogen-independent state of ER+ breast cancer cells is the key step to promote resistance to endocrine therapies. Although the crucial role of MAPK/ERK signaling pathway in estrogen-independent breast cancer cell growth is well established, the underlying mechanism is not fully understood. In this study, we profiled lncRNA expression against a focused group of lncRNAs selected from lncRNA database. CRISPR/Cas9 was employed to knockout (KO) linc-RoR in MCF-7 cells, while rescue experiments were carried out to re-express linc-RoR in KO cells. Colony formation and MTT assays were used to examine the role of linc-RoR in estrogen-independent growth and tamoxifen resistance. Western blot and qRT-PCR were used to determine the change of protein and lncRNA levels, respectively. The expression of DUSP7 in clinical specimens was downloaded from Oncomine ( www.oncomine.org ) and the dataset from Kaplan-Meier Plotter ( http://kmplot.com ) was used to analyze the clinical outcomes in relation to DUSP7. We identified that linc-RoR functions as an onco-lncRNA to promote estrogen-independent growth of ER+ breast cancer. Under estrogen deprivation, linc-RoR causes the upregulation of phosphorylated MAPK/ERK pathway which in turn activates ER signaling. Knockout of linc-RoR abrogates estrogen deprivation-induced ERK activation as well as ER phosphorylation, whereas re-expression of linc-RoR restores all above phenotypes. Moreover, we show that the ERK-specific phosphatase Dual Specificity Phosphatase 7 (DUSP7), also known as MKP-X, is involved in linc-RoR KO-induced repression of MAPK/ERK signaling. Interestingly, linc-RoR KO increases the protein stability of DUSP7, resulting in repression of ERK phosphorylation. Clinical data analysis reveal that DUSP7 expression is lower in ER+ breast cancer samples than that in ER- breast cancer. Moreover, downregulation of DUSP7 expression is associated with poor patient survival. Taken together

  10. Targeted functional imaging of estrogen receptors with 99mTc-GAP-EDL

    International Nuclear Information System (INIS)

    Takahashi, Nobukazu; Yang, David J.; Kohanim, Saady; Oh, Chang-Sok; Yu, Dong-Fang; Azhdarinia, Ali; Kurihara, Hiroaki; Kim, E.E.; Zhang, Xiaochun; Chang, Joe Y.

    2007-01-01

    To evaluate the feasibility of using 99m Tc-glutamate peptide-estradiol in functional imaging of estrogen receptor-positive [ER(+)] diseases. 3-Aminoethyl estradiol (EDL) was conjugated to glutamate peptide (GAP) to yield GAP-EDL. Cellular uptake studies of 99m Tc-GAP-EDL were conducted in ER(+) cell lines (MCF-7, 13762 and T47D). To demonstrate whether GAP-EDL increases MAP kinase activation, Western blot analysis of GAP-EDL was performed in 13762 cells. Biodistribution was conducted in nine rats with 13762 breast tumors at 0.5-4 h. Each rat was administered 99m Tc-GAP-EDL. Two animal models (rats and rabbits) were created to ascertain whether tumor uptake of 99m Tc-GAP-EDL was via an ER-mediated process. In the tumor model, breast tumor-bearing rats were pretreated with diethylstilbestrol (DES) 1 h prior to receiving 99m Tc-GAP-EDL. In the endometriosis model, part of the rabbit uterine tissue was dissected and grafted to the peritoneal wall. The rabbit was administered with 99m Tc-GAP-EDL. There was a 10-40% reduction in uptake of 99m Tc-GAP-EDL in cells treated with DES or tamoxifen compared with untreated cells. Western blot analysis showed an ERK1/2 phosphorylation process with GAP-EDL. Biodistribution studies showed that tumor uptake and tumor-to-muscle count density ratio in 99m Tc-GAP-EDL groups were significantly higher than those in 99m Tc-GAP groups at 4 h. Among 99m Tc-GAP-EDL groups, region of interest analysis of images showed that tumor-to muscle ratios were decreased in blocking groups. In the endometriosis model, the grafted uterine tissue could be visualized by 99m Tc-GAP-EDL. Cellular or tumor uptake of 99m Tc-GAP-EDL occurs via an ER-mediated process. 99m Tc-GAP-EDL is a useful agent for imaging functional ER(+) disease. (orig.)

  11. Targeted functional imaging of estrogen receptors with {sup 99m}Tc-GAP-EDL

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Nobukazu; Yang, David J.; Kohanim, Saady; Oh, Chang-Sok; Yu, Dong-Fang; Azhdarinia, Ali; Kurihara, Hiroaki; Kim, E.E. [The University of Texas M.D. Anderson Cancer Center, Division of Diagnostic Imaging, Houston, TX (United States); Zhang, Xiaochun; Chang, Joe Y. [The University of Texas M.D. Anderson Cancer Center, Division of Radiation Oncology, Houston, TX (United States)

    2007-03-15

    To evaluate the feasibility of using {sup 99m}Tc-glutamate peptide-estradiol in functional imaging of estrogen receptor-positive [ER(+)] diseases. 3-Aminoethyl estradiol (EDL) was conjugated to glutamate peptide (GAP) to yield GAP-EDL. Cellular uptake studies of {sup 99m}Tc-GAP-EDL were conducted in ER(+) cell lines (MCF-7, 13762 and T47D). To demonstrate whether GAP-EDL increases MAP kinase activation, Western blot analysis of GAP-EDL was performed in 13762 cells. Biodistribution was conducted in nine rats with 13762 breast tumors at 0.5-4 h. Each rat was administered {sup 99m}Tc-GAP-EDL. Two animal models (rats and rabbits) were created to ascertain whether tumor uptake of {sup 99m}Tc-GAP-EDL was via an ER-mediated process. In the tumor model, breast tumor-bearing rats were pretreated with diethylstilbestrol (DES) 1 h prior to receiving {sup 99m}Tc-GAP-EDL. In the endometriosis model, part of the rabbit uterine tissue was dissected and grafted to the peritoneal wall. The rabbit was administered with {sup 99m}Tc-GAP-EDL. There was a 10-40% reduction in uptake of {sup 99m}Tc-GAP-EDL in cells treated with DES or tamoxifen compared with untreated cells. Western blot analysis showed an ERK1/2 phosphorylation process with GAP-EDL. Biodistribution studies showed that tumor uptake and tumor-to-muscle count density ratio in {sup 99m}Tc-GAP-EDL groups were significantly higher than those in {sup 99m}Tc-GAP groups at 4 h. Among {sup 99m}Tc-GAP-EDL groups, region of interest analysis of images showed that tumor-to muscle ratios were decreased in blocking groups. In the endometriosis model, the grafted uterine tissue could be visualized by {sup 99m}Tc-GAP-EDL. Cellular or tumor uptake of {sup 99m}Tc-GAP-EDL occurs via an ER-mediated process. {sup 99m}Tc-GAP-EDL is a useful agent for imaging functional ER(+) disease. (orig.)

  12. Combination of methylselenocysteine with tamoxifen inhibits MCF-7 breast cancer xenografts in nude mice through elevated apoptosis and reduced angiogenesis.

    Science.gov (United States)

    Li, Zengshan; Carrier, Latonya; Belame, Aditi; Thiyagarajah, Arunthavarani; Salvo, Virgilio A; Burow, Matthew E; Rowan, Brian G

    2009-11-01

    To investigate the therapeutic effect of methylselenocysteine (MSC) combined with tamoxifen in MCF-7 breast cancer xenograft and the underlying mechanisms. MCF-7 breast cancer xenograft was established in ovariectomized female athymic nude mice and treated with tamoxifen and/or MSC. Tumor size was measured twice a week. Immunohistochemistry and TUNEL assays were used to measure ERalpha expression, ERalpha target genes (progesterone receptor (PR) and cyclin D1 expression), Ki-67 index, apoptosis and microvessel density. Combined treatment with tamoxifen and MSC synergistically inhibited tumor growth compared to MSC alone and tamoxifen alone. MSC alone or MSC + tamoxifen significantly reduced ERalpha, PR and cyclin D1, Ki67 index and microvessel density while increasing apoptosis in tumor tissues. These findings demonstrate synergistic growth inhibition of ERalpha positive breast cancer xenografts by combination of tamoxifen with organic selenium compounds. Organic selenium may provide added benefit when combined with tamoxifen in adjuvant therapy or prevention.

  13. Amphipathic benzenes are designed inhibitors of the estrogen receptor alpha/steroid receptor coactivator interaction.

    Science.gov (United States)

    Gunther, Jillian R; Moore, Terry W; Collins, Margaret L; Katzenellenbogen, John A

    2008-05-16

    We report here on the design, synthesis, and evaluation of small molecule inhibitors of the interaction between a steroid receptor coactivator and estrogen receptor alpha. These inhibitors are based upon an amphipathic benzene scaffold whose hydrophobic face mimics the leucine-rich alpha-helical consensus sequence on the steroid receptor coactivators that interacts with a shallow groove on estrogen receptor alpha. Several of these molecules are among the most potent inhibitors of this interaction described to date and are active at low micromolar concentrations in both in vitro models of estrogen receptor action and in cell-based assays of estrogen receptor-mediated coactivator interaction and transcription.

  14. The T61 human breast cancer xenograft: an experimental model of estrogen therapy of breast cancer

    DEFF Research Database (Denmark)

    Brunner, N; Spang-Thomsen, M; Cullen, K

    1996-01-01

    positive tumor which was originally derived from a T1N0M0 invasive ductal cancer and has been carried as a serially transplanted xenograft in nude mice. T61 is a hormone sensitive tumor whose growth is suppressed by both estrogen and tamoxifen, in contrast to other estrogen receptor positive tumors...... such as MCF-7 which are stimulated by estrogen. Molecular studies have demonstrated that T61 expresses easily detectable levels of mRNA for a number of peptide growth factors, including transforming growth factor alpha (TGF-alpha) and insulin-like growth factors I and II (IGF-I and IGF......-II), but not transforming growth factor beta-I (TGF-beta1). Of these, IGF-II is the only peptide whose expression is altered by endocrine therapy. Treatment of T61-bearing nude mice with physiologic doses of estrogen is accompanied by loss of IGF-II mRNA expression within 24 hours, and rapid regression of tumor. T61 tumor...

  15. Photoperiod reverses the effects of estrogens on male aggression via genomic and nongenomic pathways.

    Science.gov (United States)

    Trainor, Brian C; Lin, Shili; Finy, M Sima; Rowland, Michael R; Nelson, Randy J

    2007-06-05

    Despite recent discoveries of the specific contributions of genes to behavior, the molecular mechanisms mediating contributions of the environment are understudied. We demonstrate that the behavioral effects of estrogens on aggression are completely reversed by a discrete environmental signal, day length. Selective activation of either estrogen receptor alpha or beta decreases aggression in long days and increases aggression in short days. In the bed nucleus of the stria terminalis, one of several nuclei in a neural circuit that controls aggression, estrogen-dependent gene expression is increased in long days but not in short days, suggesting that estrogens decrease aggression by driving estrogen-dependent gene expression. Estradiol injections increased aggression within 15 min in short days but not in long days, suggesting that estrogens increase aggression in short days primarily via nongenomic pathways. These data demonstrate that the environment can dictate how hormones affect a complex behavior by altering the molecular pathways targeted by steroid receptors.

  16. Estrogen receptor-α36 is involved in pterostilbene-induced apoptosis and anti-proliferation in in vitro and in vivo breast cancer.

    Directory of Open Access Journals (Sweden)

    Chi Pan

    Full Text Available Pterostilbene (trans-3,5-dimethoxy-4'-hudroxystilbene is an antioxidant primarily found in blueberries. It also inhibits breast cancer regardless of conventional estrogen receptor (ER-α66 status by inducing both caspase-dependent and caspase-independent apoptosis. However, the pterostilbene-induced apoptosis rate in ER-α66-negative breast cancer cells is much higher than that in ER-α66-positive breast cancer cells. ER-α36, a variant of ER-α66, is widely expressed in ER-α66-negative breast cancer, and its high expression mediates the resistance of ER-α66-positive breast cancer patients to tamoxifen therapy. The aim of the present study is to determine the relationship between the antiproliferation activity of pterostilbene and ER-α36 expression in breast cancer cells. Methyl-thiazolyl-tetrazolium (MTT assay, apoptosis analysis, and an orthotropic xenograft mouse model were used to examine the effects of pterostilbene on breast cancer cells. The expressions of ER-α36 and caspase 3, the activation of ERK and Akt were also studied through RT-PCR, western blot analysis, and immunohistochemical (IHC staining. ER-α36 knockdown was found to desensitize ER-α66-negative breast cancer cells to pterostilbene treatment both in vitro and in vivo, and high ER-α36 expression promotes pterostilbene-induced apoptosis in breast cancer cells. Western blot analysis data indicate that MAPK/ERK and PI3K/Akt signaling in breast cancer cells with high ER-α36 expression are mediated by ER-α36, and are inhibited by pterostilbene. These results suggest that ER-α36 is a therapeutic target in ER-α36-positive breast cancer, and pterostilbene is an inhibitor that targets ER-α36 in the personalized therapy against ER-α36-positive breast cancer.

  17. Tamoxifen's protection against breast cancer recurrence is not reduced by concurrent use of the SSRI citalopram

    DEFF Research Database (Denmark)

    Lash, T L; Pedersen, L; Cronin-Fenton, D

    2008-01-01

    and controls were nested in a population of female residents of Northern Denmark with stages I-III oestrogen-receptor-positive breast cancer 1985-2001 and who took tamoxifen for 1, 2, or most often for 5 years. We ascertained prescription histories by linking participants' central personal registry numbers...... to prescription databases from the National Health Service. Seventeen cases (9%) and 21 controls (11%) received at least one prescription for the SSRI citalopram while taking tamoxifen (adjusted conditional odds ratio=0.85, 95% confidence interval=0.42, 1.7). We also observed no reduction of tamoxifen...

  18. Inference of hierarchical regulatory network of estrogen-dependent breast cancer through ChIP-based data

    Directory of Open Access Journals (Sweden)

    Parvin Jeffrey

    2010-12-01

    Full Text Available Abstract Background Global profiling of in vivo protein-DNA interactions using ChIP-based technologies has evolved rapidly in recent years. Although many genome-wide studies have identified thousands of ERα binding sites and have revealed the associated transcription factor (TF partners, such as AP1, FOXA1 and CEBP, little is known about ERα associated hierarchical transcriptional regulatory networks. Results In this study, we applied computational approaches to analyze three public available ChIP-based datasets: ChIP-seq, ChIP-PET and ChIP-chip, and to investigate the hierarchical regulatory network for ERα and ERα partner TFs regulation in estrogen-dependent breast cancer MCF7 cells. 16 common TFs and two common new TF partners (RORA and PITX2 were found among ChIP-seq, ChIP-chip and ChIP-PET datasets. The regulatory networks were constructed by scanning the ChIP-peak region with TF specific position weight matrix (PWM. A permutation test was performed to test the reliability of each connection of the network. We then used DREM software to perform gene ontology function analysis on the common genes. We found that FOS, PITX2, RORA and FOXA1 were involved in the up-regulated genes. We also conducted the ERα and Pol-II ChIP-seq experiments in tamoxifen resistance MCF7 cells (denoted as MCF7-T in this study and compared the difference between MCF7 and MCF7-T cells. The result showed very little overlap between these two cells in terms of targeted genes (21.2% of common genes and targeted TFs (25% of common TFs. The significant dissimilarity may indicate totally different transcriptional regulatory mechanisms between these two cancer cells. Conclusions Our study uncovers new estrogen-mediated regulatory networks by mining three ChIP-based data in MCF7 cells and ChIP-seq data in MCF7-T cells. We compared the different ChIP-based technologies as well as different breast cancer cells. Our computational analytical approach may guide biologists to

  19. Estrogenic compounds -endocrine disruptors

    OpenAIRE

    Munteanu Constantin; Hoteteu Mihai

    2011-01-01

    Endocrine disruptors (polychlorinated biphenyls, dichlorodiphenyl-trichloroethane [DDT], dioxin, and some pesticides) are estrogen-like and anti-androgenic chemicals in the environment. They mimic natural hormones, inhibit the action of hormones, or alter the normal regulatory function of the endocrine system and have potential hazardous effects on male reproductive axis causing infertility. Although testicular and prostate cancers, abnormal sexual development, undescended testis, chronic inf...

  20. Relative Roles of the Epithelial and Stromal Tissue Compartment(s) in Mediating the Actions of Relaxin and Estrogen on Cell Proliferation and Apoptosis in the Mouse Lower Reproductive Tract

    Science.gov (United States)

    YAO, LIJUAN; AGOULNIK, ALEXANDER I.; COOKE, PAUL S.; MELING, DARYL D.; SHERWOOD, O. DAVID

    2009-01-01

    Relaxin and estrogen are secreted by the ovary during the second half of pregnancy in rats and mice. Relaxin promotes marked growth of the lower reproductive tract in both species. Relaxin promotes accumulation of epithelial and stromal cells in the cervix and vagina by both stimulating cell proliferation and inhibiting apoptosis. Estrogen acting through estrogen receptor α (ERα) plays an essential permissive role in relaxin’s actions. A fundamental step toward understanding the actions of relaxin and estrogen is to identify the tissue compartments that initiate their effects. Limited studies using either antibodies to human relaxin receptor (LGR7, RXFP1) or an IRES-LacZ reporter cassette in the LGR7 gene revealed relaxin receptors in subepithelial stroma cells and smooth muscle cells but not in epithelial cells in rodent vaginal and/or cervical tissues. ERα has been reported in both stromal and epithelial compartments in rodent reproductive tract. This chapter describes ongoing studies that use relaxin bioactivity as a means of identifying the tissue compartment(s) that initiates the actions of relaxin and estrogen on the lower reproductive tract. Specifically, a tissue separation/recombination methodology in combination with LGR7-knockout mice was initially used to obtain functional evidence that stromal LGR7 is both necessary and sufficient to promote proliferation and inhibit apoptosis in both stromal and epithelial cells in mouse cervix and vagina. The tissue separation/recombination method is currently being used in conjunction with ERα-knockout mice to determine if the obligatory permissive effect of estrogen on relaxin-induced cell proliferation occurs through stromal and/or epithelial ERα. PMID:19416172

  1. Xenoestrogens are potent activators of nongenomic estrogenic responses.

    Science.gov (United States)

    Watson, Cheryl S; Bulayeva, Nataliya N; Wozniak, Ann L; Alyea, Rebecca A

    2007-02-01

    Studies of the nuclear transcriptional regulatory activities of non-physiological estrogens have not explained their actions in mediating endocrine disruption in animals and humans at the low concentrations widespread in the environment. However, xenoestrogens have rarely been tested for their ability to participate in the plethora of nongenomic steroid signaling pathways elucidated over the last several years. Here we review what is known about such responses in comparison to our recent evidence that xenoestrogens can rapidly and potently elicit signaling through nongenomic pathways culminating in functional endpoints. Both estradiol (E(2)) and compounds representing various classes of xenoestrogens (diethylstilbestrol, coumestrol, bisphenol A, DDE, nonylphenol, endosulfan, and dieldrin) act via a membrane version of the estrogen receptor-alpha on pituitary cells, and can provoke Ca(2+) influx via L-type channels, leading to prolactin (PRL) secretion. These hormones and mimetics can also cause the oscillating activation of extracellular regulated kinases (ERKs). However, individual estrogen mimetics differ in their potency and temporal phasing of these activations compared to each other and to E(2). It is perhaps in these ways that they disrupt some endocrine functions when acting in combination with physiological estrogens. Our quantitative assays allow comparison of these outcomes for each mimetic, and let us build a detailed picture of alternative signaling pathway usage. Such an understanding should allow us to determine the estrogenic or antiestrogenic potential of different types of xenoestrogens, and help us to develop strategies for preventing xenoestrogenic disruption of estrogen action in many tissues.

  2. Uptake of tamoxifen in consecutive premenopausal women under surveillance in a high-risk breast cancer clinic.

    Science.gov (United States)

    Donnelly, L S; Evans, D G; Wiseman, J; Fox, J; Greenhalgh, R; Affen, J; Juraskova, I; Stavrinos, P; Dawe, S; Cuzick, J; Howell, A

    2014-04-02

    Randomised trials of tamoxifen versus placebo indicate that tamoxifen reduces breast cancer risk by approximately 33%, yet uptake is low. Approximately 10% of women in our clinic entered the IBIS-I prevention trial. We assess the uptake of tamoxifen in a consecutive series of premenopausal women not in a trial and explore the reasons for uptake through interviews. All eligible women between 33 and 46 years at ≥17% lifetime risk of breast cancer and undergoing annual mammography in our service were invited to take a 5-year course of tamoxifen. Reasons for accepting (n=15) or declining (n=15) were explored using semi-structured interviews. Of 1279 eligible women, 136 (10.6%) decided to take tamoxifen. Women >40 years (74 out of 553 (13.4%)) and those at higher non-BRCA-associated risk were more likely to accept tamoxifen (129 out of 1109 (11.6%)). Interviews highlighted four themes surrounding decision making: perceived impact of side effects, the impact of others' experience on beliefs about tamoxifen, tamoxifen as a 'cancer drug', and daily reminder of cancer risk. Tamoxifen uptake was similar to previously ascertained uptake in a randomised controlled trial (IBIS-I). Concerns were similar in women who did or did not accept tamoxifen. Decision making appeared to be embedded in the experience of significant others.

  3. Estrogen regulation of testicular function

    Directory of Open Access Journals (Sweden)

    Akingbemi Benson T

    2005-09-01

    Full Text Available Abstract Evidence supporting a role for estrogen in male reproductive tract development and function has been collected from rodents and humans. These studies fall into three categories: i localization of aromatase and the target protein for estrogen (ER-alpha and ER-beta in tissues of the reproductive tract; ii analysis of testicular phenotypes in transgenic mice deficient in aromatase, ER-alpha and/or ER-beta gene; and, iii investigation of the effects of environmental chemicals on male reproduction. Estrogen is thought to have a regulatory role in the testis because estrogen biosynthesis occurs in testicular cells and the absence of ERs caused adverse effects on spermatogenesis and steroidogenesis. Moreover, several chemicals that are present in the environment, designated xenoestrogens because they have the ability to bind and activate ERs, are known to affect testicular gene expression. However, studies of estrogen action are confounded by a number of factors, including the inability to dissociate estrogen-induced activity in the hypothalamus and pituitary from action occurring directly in the testis and expression of more than one ER subtype in estrogen-sensitive tissues. Use of tissue-specific knockout animals and administration of antiestrogens and/or aromatase inhibitors in vivo may generate additional data to advance our understanding of estrogen and estrogen receptor biology in the developing and mature testis.

  4. Estrogen effects on the breast

    International Nuclear Information System (INIS)

    Berkowitz, J.E.; Goldblum, L.E.; Gatewood, O.M.B.; Gayler, B.W.

    1988-01-01

    Estrogen is frequently used in postmenopausal women for the treatment of menopausal symptoms and for prevention of osteoporosis. Little mention of estrogen effects on the postmenopausal breast is found in the literature. It has been suggested that estrogen replacement therapy may cause proliferative changes in the breast, manifested by mammographically dense breasts. The authors present five patients in whom the fibroglandular tissue dramatically increased after initiation of hormonal therapy. One patient's mammogram returned to baseline 2 weeks after discontinuation of treatment. Recognition of the estrogen effect is important since appearing densities are cause for suspicion in the postmenopausal breast and since very dense breasts can obscure masses

  5. Tool Weighs Benefits, Risks of Raloxifene or Tamoxifen to Prevent Breast Cancer

    Science.gov (United States)

    Researchers have developed a benefit-risk index to help guide decisions on whether postmenopausal women at increased risk of developing breast cancer should take raloxifene or tamoxifen to reduce that risk.

  6. Resistance to Tamoxifen: A Consequence of Altered p27Kipl Regulation During Breast Cancer

    National Research Council Canada - National Science Library

    Slingerland, Joyce

    2002-01-01

    .... The elucidation of mechanisms whereby estradiol:ER influences cell cycle regulators and how these are blocked by Tamoxifen is highly relevant to the development of new treatments for steroid resistant breast cancer...

  7. Modeling the interaction of binary and ternary mixtures of estradiol and bisphenol A or its analogues in an in vitro estrogen mediated transcriptional activation assay (T47D-KBlue).

    Science.gov (United States)

    Bisphenol A is a ubiquitous monomer used to manufacture polycarbonate plastics. Exposure ofhuman and wildlife populations to bisphenol A and its analogs is widespread and well documented. Bisphenol A is hypothesized to be estrogenic in both in vivo and in vitro studies and has be...

  8. Ca2+ channel subunit α 1D promotes proliferation and migration of endometrial cancer cells mediated by 17β-estradiol via the G protein-coupled estrogen receptor.

    Science.gov (United States)

    Hao, Juan; Bao, Xiaoxia; Jin, Bo; Wang, Xiujuan; Mao, Zebin; Li, Xiaoping; Wei, Lihui; Shen, Danhua; Wang, Jian-Liu

    2015-07-01

    Calcium and calcium channels are closely related to the estrogen-induced nongenomic effect of endometrial carcinoma, but the specific role of calcium channels is unknown. This study aimed to explore the expression and the biologic effect of the L-type calcium channel in endometrial carcinoma cells and to clarify the molecular mechanism of the relationship between L-type calcium channels and estrogen. The immunohistochemical results showed that Ca(2+) channel subunit α 1D (Cav1.3) expression was high in atypical hyperplasia (1.90 ± 0.35) and endometrial carcinoma tissues (2.05 ± 0.82) but weak (0.80 ± 0.15) in benign endometrial tissues (P cancer cells. Taken together, Cav1.3 was overexpressed in atypical hyperplasia and endometrial carcinoma, and the estrogen-induced phosphorylation of downstream molecular ERK1/2 and CREB is the result of activation of the GPER pathway. L-type channel Cav1.3 is required for estrogen-stimulated Ca(2+) influx and contributes broadly to the development of endometrial cancer. The Cav1.3 channel may be a new target for endometrial carcinoma treatment. © FASEB.

  9. Breast cancer case using tamoxifen during pregnancy: a case report ...

    African Journals Online (AJOL)

    This is a case of 32 years old nulliparous female who was diagnosed in November 2004 as a case of carcinoma of the right breast , luminal A , (Estrogen Receptor positive Progesterone receptor negative, Her 2 negative, Ki67 10 %), poorly differentiated invasive ductal cancer, TNM stage,T2 N0 MO. She had a wide local ...

  10. Effects of Topical Tamoxifen on Wound Healing of Burned Skin in Rats

    Directory of Open Access Journals (Sweden)

    Shaban Mehrvarz

    2017-09-01

    Full Text Available Background This study aimed to assess the effects of the topical application of tamoxifen on wound healing of burned skin in Wistar rats by evaluating 3 healing characteristics: fibrotic tissue thickness (FTT, scar surface area (SSA, and angiogenesis in the healed scar tissue. Methods Eighteen male Wistar rats were used in this study. A third-degree burn wound was made on the shaved animals’ back, measuring 2×2×2 cm. In the first group, a 2% tamoxifen ointment was applied to the wound twice daily for 8 weeks. The second group received a placebo ointment during the same period. The third group did not receive any treatment and served as the control group. Results The median (interquartile range=[Q1, Q3] FTT was 1.35 (1.15, 1.62 mm, 1.00 (0.95, 1.02 mm, and 1.25 (0.8, 1.5 mm in the control, tamoxifen, and placebo groups, respectively (P=0.069. However, the FTT in the tamoxifen group was less than in the placebo and control groups. The median angiogenesis was 3.5 (3.00, 6.25, 8.00 (6.75, 9.25, and 7.00 (5.50, 8.25 vessels per high-power field for the control, tamoxifen, and placebo groups, respectively (P=0.067. However, the median angiogenesis was higher in the tamoxifen group than in the control group. No significant difference was observed in the mean SSA between the tamoxifen group and the control group (P=0.990. Conclusions Local application of tamoxifen increased angiogenesis and decreased the FTT, with no change in the SSA in burned skin areas. These effects are expected to expedite the wound healing process, reducing contracture and preventing hypertrophic scar and keloid formation.

  11. Stromal-Epithelial Interactions and Tamoxifen-Sensitivity: A Bench-to-Bedside Model of Chemoprevention

    Science.gov (United States)

    2008-05-01

    stroke, or abnormal uterine bleeding were not eligible to participate. Thirty-four women were offered tamoxifen chemoprevention; 18 women elected to take...were incubated with anti-ERa antibody (DAKO, 1D5). A minimum of 100 cells was assessed on the sample judged to be most abnormal by 2 readers. The...binding site in human and rat uterine cells, as well as in other tissues. Tamoxifen also directly inhibits calmodulin in a calcium-dependent manner (44

  12. Estetrol, a Fetal Selective Estrogen Receptor Modulator, Acts on the Vagina of Mice through Nuclear Estrogen Receptor α Activation.

    Science.gov (United States)

    Benoit, Thibaut; Valera, Marie-Cecile; Fontaine, Coralie; Buscato, Melissa; Lenfant, Francoise; Raymond-Letron, Isabelle; Tremollieres, Florence; Soulie, Michel; Foidart, Jean-Michel; Game, Xavier; Arnal, Jean-Francois

    2017-11-01

    The genitourinary syndrome of menopause has a negative impact on quality of life of postmenopausal women. The treatment of vulvovaginal atrophy includes administration of estrogens. However, oral estrogen treatment is controversial because of its potential risks on venous thrombosis and breast cancer. Estetrol (E4) is a natural estrogen synthesized exclusively during pregnancy by the human fetal liver and initially considered as a weak estrogen. However, E4 was recently evaluated in phase 1 to 2 clinical studies and found to act as an oral contraceptive in combination with a progestin, without increasing the level of coagulation factors. We recently showed that E4 stimulates uterine epithelial proliferation through nuclear estrogen receptor (ER) α, but failed to elicit endothelial responses. Herein, we first evaluated the morphological and functional impacts of E4 on the vagina of ovariectomized mice, and we determined the molecular mechanism mediating these effects. Vaginal epithelial proliferation and lubrication after stimulation were found to increase after E4 chronic treatment. Using a combination of pharmacological and genetic approaches, we demonstrated that these E4 effects on the vagina are mediated by nuclear ERα activation. Altogether, we demonstrate that the selective activation of nuclear ERα is both necessary and sufficient to elicit functional and structural effects on the vagina, and therefore E4 appears promising as a therapeutic option to improve vulvovaginal atrophy. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  13. Estrogen receptor alpha is cell cycle-regulated and regulates the cell cycle in a ligand-dependent fashion.

    Science.gov (United States)

    JavanMoghadam, Sonia; Weihua, Zhang; Hunt, Kelly K; Keyomarsi, Khandan

    2016-06-17

    Estrogen receptor alpha (ERα) has been implicated in several cell cycle regulatory events and is an important predictive marker of disease outcome in breast cancer patients. Here, we aimed to elucidate the mechanism through which ERα influences proliferation in breast cancer cells. Our results show that ERα protein is cell cycle-regulated in human breast cancer cells and that the presence of 17-β-estradiol (E2) in the culture medium shortened the cell cycle significantly (by 4.5 hours, P fashion. These results provide the rationale for an effective treatment strategy that includes a cell cycle inhibitor in combination with a drug that lowers estrogen levels, such as an aromatase inhibitor, and an antiestrogen that does not result in the degradation of ERα, such as tamoxifen.

  14. Combination of low-concentration of novel phytoestrogen (8,9)-furanyl-pterocarpan-3-ol from Pachyrhizus erosus attenuated tamoxifen-associated growth inhibition on breast cancer T47D cells

    Science.gov (United States)

    Nurrochmad, Arief; Lukitaningsih, Endang; Monikawati, Ameilinda; Septhea, Dita Brenna; Meiyanto, Edy

    2013-01-01

    Objective To investigate the estrogenic effect of (8,9)-furanyl-pterocarpan-3-ol (FPC) on growth of human breast cancer T47D cells and the interactions between the FPC and tamoxifen (TAM), on the growth of estrogen receptor-dependent breast cancer T47D cells. Methods The proliferation effect of FPC were conducted on T47D cells in vitro by MTT test. T47D cells were treated with FPC alone (0.01-200 µmol/L) or in combination with TAM 20 nmol/L. Furthermore, the expression of ERα or c-Myc were also determined by immunohistochemistry. Results The results indicated that administration of an anti-estrogen TAM showed growth inhibitory effect on T47D cells, wheraes co-administered with low concentration (less than 1 µmol/L) of FPC attenuated to promote cell proliferation. In contrast, the combination of TAM with higher doses (more than 20 µmol/L) of FPC showed growth inhibitory. This result was supported by immunocytochemistry studies that the administration of 20 nmol/L TAM down-regulated ER-α and c-Myc, but the combination of 20 nmol/L TAM and 1 µmol/L FPC robustly up-regulated expression of ER-α. Thus, the reduced growth inhibition of TAM 20 nmol/L by FPC 1 µmol/L on T47D cells may act via the modulation of ER-α. Conclusions The findings indicate and suggest that FPC had estrogenic activity at low concentrations and anti-estrogenic effect that are likely to be regulated by c-Myc and estrogen receptors. We also confirm that low concentration of FPC attenuated the growth-inhibitory effects of TAM on mammary tumor prevention. Therefore, the present study suggests that caution is warranted regarding the consumption of dietary FPC by breast cancer patients while on TMA therapy.

  15. The effect of the phytoestrogens genistein, daidzein, and equol on the growth of tamoxifen-resistant T47D/PKC alpha.

    Science.gov (United States)

    Tonetti, Debra A; Zhang, Yiyun; Zhao, Huiping; Lim, Sok-Bee; Constantinou, Andreas I

    2007-01-01

    Soy supplements are often consumed by women for alleviating menopausal symptoms or for the perceived protective effects against breast cancer. More concerning is the concurrent consumption of soy isoflavones with tamoxifen (TAM) for prevention or treatment of breast cancer. We previously described a T47D:A18/protein kinase C (PKC)alpha TAM-resistant tumor model that exhibits autonomous growth and estradiol-induced tumor regression. We compared the estrogenicity of the isoflavones genistein, daidzein, and the daidzein metabolite equol in the parental T47D:A18 and T47D:A18/PKC alpha cell lines in vitro and in vivo. Whereas equol exerts estrogenic effects on T47D:A18 cells in vitro, none of the isoflavones stimulated T47D:A18 tumor growth. T47D:A18/PKC alpha tumor growth was partially stimulated by genistein, yet partially inhibited by daidzein. Interestingly, coadministration of TAM with either daidzein or genistein produced tumors of greater size than with TAM alone. These findings suggest that simultaneous consumption of isoflavone supplements with TAM may not be safe.

  16. Survival and safety of exemestane versus tamoxifen after 2-3 years' tamoxifen treatment (Intergroup Exemestane Study): a randomised controlled trial.

    Science.gov (United States)

    Coombes, R C; Kilburn, L S; Snowdon, C F; Paridaens, R; Coleman, R E; Jones, S E; Jassem, J; Van de Velde, C J H; Delozier, T; Alvarez, I; Del Mastro, L; Ortmann, O; Diedrich, K; Coates, A S; Bajetta, E; Holmberg, S B; Dodwell, D; Mickiewicz, E; Andersen, J; Lønning, P E; Cocconi, G; Forbes, J; Castiglione, M; Stuart, N; Stewart, A; Fallowfield, L J; Bertelli, G; Hall, E; Bogle, R G; Carpentieri, M; Colajori, E; Subar, M; Ireland, E; Bliss, J M

    2007-02-17

    Early improvements in disease-free survival have been noted when an aromatase inhibitor is given either instead of or sequentially after tamoxifen in postmenopausal women with oestrogen-receptor-positive early breast cancer. However, little information exists on the long-term effects of aromatase inhibitors after treatment, and whether these early improvements lead to real gains in survival. 4724 postmenopausal patients with unilateral invasive, oestrogen-receptor-positive or oestrogen-receptor-unknown breast cancer who were disease-free on 2-3 years of tamoxifen, were randomly assigned to switch to exemestane (n=2352) or to continue tamoxifen (n=2372) for the remainder of a 5-year endocrine treatment period. The primary endpoint was disease-free survival; overall survival was a secondary endpoint. Efficacy analyses were intention-to-treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN11883920. After a median follow-up of 55.7 months (range 0-89.7), 809 events contributing to the analysis of disease-free survival had been reported (354 exemestane, 455 tamoxifen); unadjusted hazard ratio 0.76 (95% CI 0.66-0.88, p=0.0001) in favour of exemestane, absolute benefit 3.3% (95% CI 1.6-4.9) by end of treatment (ie, 2.5 years after randomisation). 222 deaths occurred in the exemestane group compared with 261 deaths in the tamoxifen group; unadjusted hazard ratio 0.85 (95% CI 0.71-1.02, p=0.08), 0.83 (0.69-1.00, p=0.05) when 122 patients with oestrogen-receptor-negative disease were excluded. Our results suggest that early improvements in disease-free survival noted in patients who switch to exemestane after 2-3 years on tamoxifen persist after treatment, and translate into a modest improvement in overall survival.

  17. Estrogenic compounds -endocrine disruptors

    Directory of Open Access Journals (Sweden)

    Munteanu Constantin

    2011-11-01

    Full Text Available Endocrine disruptors (polychlorinated biphenyls, dichlorodiphenyl-trichloroethane [DDT], dioxin, and some pesticides are estrogen-like and anti-androgenic chemicals in the environment. They mimic natural hormones, inhibit the action of hormones, or alter the normal regulatory function of the endocrine system and have potential hazardous effects on male reproductive axis causing infertility. Although testicular and prostate cancers, abnormal sexual development, undescended testis, chronic inflammation, Sertoli-cell-only pattern, hypospadias, altered pituitary and thyroid gland functions are also observed, the available data are insufficient to deduce worldwide conclusions.

  18. Effect of tamoxifen and fulvestrant long-term treatments on ROS production and (pro/anti)-oxidant enzymes mRNA levels in a MCF-7-derived breast cancer cell line.

    Science.gov (United States)

    Badia, Eric; Morena, Marion; Lauret, Céline; Boulahtouf, Abdelhay; Boulle, Nathalie; Cavaillès, Vincent; Balaguer, Patrick; Cristol, Jean Paul

    2016-09-01

    Reactive oxygen species (ROS) are key players in the apoptotic effects induced by short-term tamoxifen treatment of breast cancer cells, but also in acquired resistance following long-term treatment. Whereas the use of the selective estrogen receptor down-regulator fulvestrant is promising, especially in patients who develop tamoxifen resistance, only few studies addressed its implication in the modulation of cellular redox status. The regulation of (pro/anti)-oxidant players were first investigated at the mRNA level in a MCF-7-derived cell line after short-term (24 h) estradiol treatment. Long-term anti-estrogen treated MCF-7 derived cell lines were also developed: 3 months of 4-hydroxytamoxifen alone (MCF7L-OHTLT) or followed by 3 months of fulvestrant (MCF7L-ICILT). Growth properties, hormone sensitivity, receptor content, ROS production and relative mRNA expression of pro or antioxidant enzymes were evaluated in these long-term treated cell lines. Short-term estradiol treatment showed a hormone sensitivity of Nox2, GPx1, GPx2 and SOD1 mRNA levels. The long-term fulvestrant treatment (3 months) of MCF7L-OHTLT led to a reduced level of ROS production accompanied with a drastic drop of the accessory protein p22(phox) mRNA. This ROS reduction, although not clearly related to antioxidant enzymes level, seems to be involved in fulvestrant sensitivity of long-term anti-estrogen treated cells, as suggested by the effects of antiradical tempol treatment. When compared to long-term 4-hydroxytamoxifen-treated breast cancer cells, addition of fulvestrant treatment was able to diminish ROS production and p22(phox) mRNA level, and made cells more sensitive to growth inhibition induced by tempol. These effects may be a valuable asset of the fulvestrant treatment.

  19. ESTROGEN IN THE LIMBIC SYSTEM

    NARCIS (Netherlands)

    ter Horst, Gert J.; Litwack, G

    2010-01-01

    Estrogens are a group of steroid hormones that function as the primary female sex hormone. Estrogens not only have an important role in the regulation of the estrous or menstrual cycle but also control, for example, bone formation, the cardiovascular system, and cognitive functions. Estradiol (E2),

  20. Uterine micro-environment and estrogen-dependent regulation of osteopontin expression in mouse blastocyst.

    Science.gov (United States)

    Xie, Qing-Zhen; Qi, Qian-Rong; Chen, Ying-Xian; Xu, Wang-Ming; Liu, Qian; Yang, Jing

    2013-07-11

    Embryo implantation is a highly synchronized bioprocess between an activated blastocyst and a receptive uterus. In mice, successful implantation relies on the dynamic interplay of estrogen and progesterone; however, the key mediators downstream of these hormones that act on blastocyst competency and endometrium receptivity acquisition are largely unknown. In this study, we showed that the expression of osteopontin (OPN) in mouse blastocysts is regulated by ovarian estrogen and uterine micro-environment. OPN mRNA is up-regulated in mouse blastocyst on day 4 of pregnancy, which is associated with ovarian estrogen secretion peak. Hormone treatment in vivo demonstrated that OPN expression in a blastocyst is regulated by estrogen through an estrogen receptor (ER). Our results of the delayed and activated implantation model showed that OPN expression is induced after estrogen injection. While estrogen treatment during embryo culture in vitro showed less effect on OPN expression, the tubal ligation model on day 3 of pregnancy confirmed that the regulation of estrogen on OPN expression in blastocyst might, through some specific cytokines, have existed in a uterine micro-environment. Collectively, our study presents that estrogen regulates OPN expression and it may play an important role during embryo implantation by activating blastocyst competence and facilitating the endometrium acceptable for active blastocyst.

  1. Estrogen Effects on Wound Healing

    Directory of Open Access Journals (Sweden)

    Huann-Cheng Horng

    2017-11-01

    Full Text Available Wound healing is a physiological process, involving three successive and overlapping phases—hemostasis/inflammation, proliferation, and remodeling—to maintain the integrity of skin after trauma, either by accident or by procedure. Any disruption or unbalanced distribution of these processes might result in abnormal wound healing. Many molecular and clinical data support the effects of estrogen on normal skin homeostasis and wound healing. Estrogen deficiency, for example in postmenopausal women, is detrimental to wound healing processes, notably inflammation and re-granulation, while exogenous estrogen treatment may reverse these effects. Understanding the role of estrogen on skin might provide further opportunities to develop estrogen-related therapy for assistance in wound healing.

  2. Oleocanthal Modulates Estradiol-Induced Gene Expression Involving Estrogen Receptor α.

    Science.gov (United States)

    Keiler, Annekathrin Martina; Djiogue, Sefirin; Ehrhardt, Tino; Zierau, Oliver; Skaltsounis, Leandros; Halabalaki, Maria; Vollmer, Günter

    2015-09-01

    Oleocanthal is a bioactive compound from olive oil. It has attracted considerable attention as it is anti-inflammatory, antiproliferative, and has been shown to possess neuroprotective properties in vitro and in vivo. Delineated from its polyphenolic structure, the aim of this study was to characterize oleocanthal towards estrogenic properties. This might contribute to partly explain the beneficial effects described for the Mediterranean diet. Estrogenic properties of oleocanthal were assessed by different methods: a) stimulation of reporter gene activity in MVLN or RNDA cells either expressing estrogen receptor α or β, b) stimulation of luciferase reporter gene activity in U2OS osteosarcoma cells expressing estrogen receptor α or β, and c) elucidation of the impact on estradiol-induced gene expression in U2OS cells transduced with both estrogen receptors. Depending on the cell line origin, oleocanthal inhibited luciferase activity (MVLN, U2OS-estrogen receptor β) or weakly induced reporter gene activity at 10 µM in U2OS-estrogen receptor α cells. However, oleocanthal inhibited stimulation of luciferase activity by estradiol from both estrogen receptors. Oleocanthal, if given alone, did not stimulate gene expression in U2OS cells, but it significantly modulated the response of estradiol. Oleocanthal enhanced the effect of estradiol on the regulation of those genes, which are believed to be regulated through heterodimeric estrogen receptors. As the estrogenic response pattern of oleocanthal is rather unique, we compared the results obtained with oleacein. Oleocanthal binds to both estrogen receptors inducing estradiol-agonistic or antiagonistic effects depending on the cell line. Regarding regulation of gene expression in U2OS-estrogen receptor α/β cells, oleocanthal and oleacein enhanced estradiol-mediated regulation of heterodimer-regulated genes. Georg Thieme Verlag KG Stuttgart · New York.

  3. Estrogen regulates stemness and senescence of bone marrow stromal cells to prevent osteoporosis via ERβ-SATB2 pathway.

    Science.gov (United States)

    Wu, Geng; Xu, Rongyao; Zhang, Ping; Xiao, Tao; Fu, Yu; Zhang, Yuchao; Du, Yifei; Ye, Jinhai; Cheng, Jie; Jiang, Hongbing

    2018-05-01

    Decline of pluripotency in bone marrow stromal cells (BMSCs) associated with estrogen deficiency leads to a bone formation defect in osteoporosis. Special AT-rich sequence binding protein 2 (SATB2) is crucial for maintaining stemness and osteogenic differentiation of BMSCs. However, whether SATB2 is involved in estrogen-deficiency associated-osteoporosis is largely unknown. In this study, we found that estrogen mediated pluripotency and senescence of BMSCs, primarily through estrogen receptor beta (ERβ). BMSCs from the OVX rats displayed increased senescence and weaker SATB2 expression, stemness, and osteogenic differentiation, while estrogen could rescue these phenotypes. Inhibition of ERβ or ERα confirmed that SATB2 was associated with ERβ in estrogen-mediated pluripotency and senescence of BMSCs. Furthermore, estrogen mediated the upregulation of SATB2 through the induction of ERβ binding to estrogen response elements (ERE) located at -488 of the SATB2 gene. SATB2 overexpression alleviated senescence and enhanced stemness and osteogenic differentiation of OVX-BMSCs. SATB2-modified BMSCs transplantation could prevent trabecular bone loss in an ovariectomized rat model. Collectively, our study revealed the role of SATB2 in stemness, senescence, and osteogenesis of OVX-BMSCs. These results indicate that estrogen prevents osteoporosis by promoting stemness and osteogenesis, and inhibiting senescence of BMSCs through an ERβ-SATB2 pathway. Therefore, SATB2 is a novel anti-osteoporosis target gene. © 2017 Wiley Periodicals, Inc.

  4. Potent inhibition of rhabdoid tumor cells by combination of flavopiridol and 4OH-tamoxifen

    International Nuclear Information System (INIS)

    Cimica, Velasco; Smith, Melissa E; Zhang, Zhikai; Mathur, Deepti; Mani, Sridhar; Kalpana, Ganjam V

    2010-01-01

    Rhabdoid Tumors (RTs) are highly aggressive pediatric malignancies with poor prognosis. There are currently no standard or effective treatments for RTs in part because treatments are not designed to specifically target these tumors. Our previous studies indicated that targeting the cyclin/cdk pathway is a novel therapeutic strategy for RTs and that a pan-cdk inhibitor, flavopiridol, inhibits RT growth. Since the toxicities and narrow window of activity associated with flavopiridol may limit its clinical use, we tested the effect of combining flavopiridol with 4-hydroxy-Tamoxifen (4OH-Tam) in order to reduce the concentration of flavopiridol needed for inhibition of RTs. The effects of flavopiridol, 4OH-Tam, and their combination on RT cell cycle regulation and apoptosis were assessed by: i) cell survival assays, ii) FACS analysis, iii) caspase activity assays, and iv) immunoblot analysis. Furthermore, the role of p53 in flavopiridol- and 4OH-Tam-mediated induction of cell cycle arrest and apoptosis was characterized using RNA interference (siRNA) analysis. The effect of p53 on flavopiridol-mediated induction of caspases 2, 3, 8 and 9 was also determined. We found that the combination of flavopiridol and 4OH-Tam potently inhibited the growth of RT cells. Low nanomolar concentrations of flavopiridol induced G 2 arrest, which was correlated to down-modulation of cyclin B1 and up-regulation of p53. Addition of 4OH-Tam did not affect flavopiridol-mediated G 2 arrest, but enhanced caspase 3,7-mediated apoptosis induced by the drug. Abrogation of p53 by siRNA abolished flavopiridol-induced G 2 arrest, but enhanced flavopiridol- (but not 4OH-Tam-) mediated apoptosis, by enhancing caspase 2 and 3 activities. Combining flavopiridol with 4OH-Tam potently inhibited the growth of RT cells by increasing the ability of either drug alone to induce caspases 2 and 3 thereby causing apoptosis. The potency of flavopiridol was enhanced by abrogation of p53. Our results warrant further

  5. SRC drives growth of antiestrogen resistant breast cancer cell lines and is a marker for reduced benefit of tamoxifen treatment

    DEFF Research Database (Denmark)

    Larsen, Sarah L; Laenkholm, Anne-Vibeke; Duun-Henriksen, Anne Katrine

    2015-01-01

    effect on tamoxifen resistant cell growth, whereas dasatinib in combination with tamoxifen had no additive inhibitory effect on fulvestrant resistant growth. When performing immunohistochemical staining on 268 primary tumors from breast cancer patients who had received tamoxifen as first line endocrine...... treatment, we found that membrane expression of Src in the tumor cells was significant associated with reduced disease-free and overall survival. In conclusion, Src was identified as target for treatment of antiestrogen resistant T47D breast cancer cells. For tamoxifen resistant T47D cells, combined...

  6. Two years of tamoxifen or no adjuvant systemic therapy for patients with high-risk breast cancer

    DEFF Research Database (Denmark)

    Jensen, Maj-Britt; Krarup, Jens Fabricius; Palshof, Torben

    2018-01-01

    randomly assigned to two years of daily placebo or tamoxifen. Survival statistics was collected from the Danish Civil Registration System. RESULTS: The five-year invasive breast cancer recurrence (BCR) rate was 43.2% in the placebo arm and 31.9% in the tamoxifen arm. Compared with the placebo arm...... the hazard ratio for a BCR event was 0.73 in the tamoxifen arm (p = .07). With an estimated median follow-up on overall survival of 40.9 years, 154 and 145 patients had died in the placebo and tamoxifen arm, respectively. After adjustment for baseline characteristics a significant reduction in mortality...

  7. Brain Function, Structure, and Neurochemistry After Tamoxifen/Chemotherapy Assessed by Neuropsychologic Testing and 1H Magnetic Resonance Spectroscopy

    National Research Council Canada - National Science Library

    Ernst, Thomas

    2001-01-01

    .... Most recently, several reports have used a sensitive method (neuropsychological testing) to evaluate younger women with breast cancer after chemotherapy and hormonal modifying therapy (with tamoxifen...

  8. Designer interface peptide grafts target estrogen receptor alpha dimerization

    International Nuclear Information System (INIS)

    Chakraborty, S.; Asare, B.K.; Biswas, P.K.; Rajnarayanan, R.V.

    2016-01-01

    The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization. Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

  9. Designer interface peptide grafts target estrogen receptor alpha dimerization

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, S. [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Asare, B.K. [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States); Biswas, P.K., E-mail: pbiswas@tougaloo.edu [Laboratory of Computational Biophysics & Bioengineering, Department of Physics, Tougaloo College, Tougaloo, MS 39174 (United States); Rajnarayanan, R.V., E-mail: rajendra@buffalo.edu [Department of Pharmacology and Toxicology, University of Buffalo, Buffalo, NY 14214 (United States)

    2016-09-09

    The nuclear transcription factor estrogen receptor alpha (ERα), triggered by its cognate ligand estrogen, regulates a variety of cellular signaling events. ERα is expressed in 70% of breast cancers and is a widely validated target for anti-breast cancer drug discovery. Administration of anti-estrogen to block estrogen receptor activation is still a viable anti-breast cancer treatment option but anti-estrogen resistance has been a significant bottle-neck. Dimerization of estrogen receptor is required for ER activation. Blocking ERα dimerization is therefore a complementary and alternative strategy to combat anti-estrogen resistance. Dimer interface peptide “I-box” derived from ER residues 503–518 specifically blocks ER dimerization. Recently using a comprehensive molecular simulation we studied the interaction dynamics of ERα LBDs in a homo-dimer. Based on this study, we identified three interface recognition peptide motifs LDKITDT (ERα residues 479–485), LQQQHQRLAQ (residues 497–506), and LSHIRHMSNK (residues 511–520) and reported the suitability of using LQQQHQRLAQ (ER 497–506) as a template to design inhibitors of ERα dimerization. Stability and self-aggregation of peptide based therapeutics poses a significant bottle-neck to proceed further. In this study utilizing peptide grafted to preserve their pharmacophoric recognition motif and assessed their stability and potential to block ERα mediated activity in silico and in vitro. The Grafted peptides blocked ERα mediated cell proliferation and viability of breast cancer cells but did not alter their apoptotic fate. We believe the structural clues identified in this study can be used to identify novel peptidometics and small molecules that specifically target ER dimer interface generating a new breed of anti-cancer agents. - Highlights: • Designer peptide grafts retain core molecular recognition motif during MD simulations. • Designer peptide grafts with Poly-ALA helix form stable

  10. Artonin E and Structural Analogs from Artocarpus Species Abrogates Estrogen Receptor Signaling in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Imaobong Etti

    2016-06-01

    Full Text Available The increasing rate of mortality ensued from breast cancer has encouraged research into safer and efficient therapy. The human Estrogen receptor α has been implicated in the majority of reported breast cancer cases. Molecular docking employing Glide, Schrodinger suite 2015, was used to study the binding affinities of small molecules from the Artocarpus species after their drug-like properties were ascertained. The structure of the ligand-binding domain of human Estrogen receptor α was retrieved from Protein Data Bank while the structures of compounds were collected from PubChem database. The binding interactions of the studied compounds were reported as well as their glide scores. The best glide scored ligand, was Artonin E with a score of −12.72 Kcal when compared to other studied phytomolecules and it evoked growth inhibition of an estrogen receptor positive breast cancer cells in submicromolar concentration (3.8–6.9 µM in comparison to a reference standard Tamoxifen (18.9–24.1 µM within the tested time point (24–72 h. The studied ligands, which had good interactions with the target receptor, were also drug-like when compared with 95% of orally available drugs with the exception of Artoelastin, whose predicted physicochemical properties rendered it less drug-like. The in silico physicochemical properties, docking interactions and growth inhibition of the best glide scorer are indications of the anti-breast cancer relevance of the studied molecules.

  11. VASCULAR AGING IN WOMEN: IS ESTROGEN THE FOUNTAIN OF YOUTH?

    Directory of Open Access Journals (Sweden)

    Susana eNovella

    2012-06-01

    Full Text Available Aging is a physiological process associated with structural and functional changes in vasculature, including endothelial dysfunction, arterial stiffening and remodeling, impaired angiogenesis, and defective vascular repair, and with an increasing prevalence of atherosclerosis. The risk of cardiovascular disease differs between men and women, remaining lower in women during their fertile years and reaching values similar to their male peers after menopause. Menopause is marked by the loss of endogenous estrogen production. Therefore, estrogens have been implicated in premenopausal protection from cardiovascular disease, an assumption supported by experimental and some clinical studies, where estrogen induces protective effects in vascular endothelium. Indeed, estradiol promotes endothelial vasodilator synthesis, including NO production through increased expression and activity of endothelial nitric oxide synthase, and modulates prostacyclin and thromboxane A2 release; the thromboxane A2 pathway plays a key role in regulating vascular tone in females in both normal and in pathophysiologic states.Contrary to experimental results, some clinical trials found no cardiovascular benefit from estrogen replacement therapy in aged postmenopausal women. These discrepancies could be due to the Timing Hypothesis which suggests that estrogen-mediated vascular benefits may occur only before the detrimental effects of aging are established in the vasculature. Thus, there is still a gap in the knowledge, understanding, and general awareness of mechanisms for cardiovascular aging in women.In this review, we discuss clinical and experimental data on the effects of aging, estrogens and hormonal replacement therapy on vascular function of females to delve into how menopause and aging contribute jointly to vascular aging and how estrogen modulates the vascular responses at different ages.

  12. Effect of tamoxifen on the coronary vascular reactivity of spontaneously hypertensive female rats

    Directory of Open Access Journals (Sweden)

    M.V. Borgo

    2011-08-01

    Full Text Available Tamoxifen has been associated with a reduction in the incidence of myocardial infarction. However, the effects of tamoxifen on coronary reactivity have not been fully elucidated. The objective of this study was to determine the effects of chronic treatment with tamoxifen on coronary vascular reactivity in spontaneously hypertensive rats (SHR. Female SHR were divided into four groups (N = 7 each: sham-operated (SHAM, sham-operated and treated with tamoxifen (10 mg/kg by gavage for 90 days (TAMOX, ovariectomized (OVX, and ovariectomized and treated with tamoxifen (OVX+TAMOX. Mean arterial pressure (MAP, heart rate (HR, coronary perfusion pressure (CPP, and coronary vascular reactivity were measured. MAP and HR were reduced (9.42 and 11.67%, respectively in the OVX+TAMOX group compared to the OVX group (P < 0.01. The coronary vascular reactivity of the OVX+TAMOX group presented smaller vasoconstrictor responses to acetylcholine (2-64 µg when compared to the OVX group (P < 0.01 and this response was similar to that of the SHAM group. The adenosine-induced vasodilator response was greater in the TAMOX group compared to the SHAM and OVX groups (P < 0.05. Baseline CPP was higher in OVX+TAMOX and TAMOX groups (136 ± 3.6 and 130 ± 1.5 mmHg than in OVX and SHAM groups (96 ± 2 and 119 ± 2.3 mmHg; P < 0.01. Tamoxifen, when combined with OVX, attenuated the vasoconstriction induced by acetylcholine and increased the adenosine-induced vasodilatory response, as well as reducing the MAP, suggesting beneficial effects of tamoxifen therapy on coronary vascular reactivity after menopause.

  13. Tamoxifen-loaded polymeric micelles: preparation, physico-chemical characterization and in vitro evaluation studies.

    Science.gov (United States)

    Cavallaro, Gennara; Maniscalco, Laura; Licciardi, Mariano; Giammona, Gaetano

    2004-11-20

    Several samples of polymeric micelles, formed by amphiphilic derivatives of PHEA, obtained by grafting into polymeric backbone of PEGs and/or hexadecylamine groups (PHEA-PEG-C(16) and PHEA-C(16)) and containing different amount of Tamoxifen, were prepared. All Tamoxifen-loaded polymeric micelles showed to increase drug water solubility. TEM studies provided evidence of the formation of supramolecular core/shell architectures containing drug, in the nanoscopic range and with spherical shape. Samples with different amount of encapsulated Tamoxifen were subjected to in vitro cytotoxic studies in order to evaluate the effect of Tamoxifen micellization on cell growth inhibition. All samples of Tamoxifen-loaded polymeric micelles showed a significantly higher antiproliferative activity in comparison with free drug, probably attributable to fluidification of cellular membranes, caused by amphiphilic copolymers, that allows a higher penetration of the drug into tumoral cells. To gain preliminary information about the potential use of prepared micelles as Tamoxifen drug delivery systems, studies evaluating drug release ability of micelle systems in media mimicking biological fluids (buffer solutions at pH 7.4 and 5.5) and in human plasma were carried out. These studies, performed evaluating the amount of Tamoxifen that remains in solution as a function of time, showed that at pH 7.4, as well as in plasma, PHEA-C(16) polymeric micelles were able to release lower drug amounts than PHEA-PEG(5000)-C(16) ones, while at pH 5.5, the behavior difference between two kind of micelles was less pronounced.

  14. Inhibition of herpes simplex virus type 1 entry by chloride channel inhibitors tamoxifen and NPPB

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Kai [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of Life Science and Technology, Jinan University, Guangzhou (China); Chen, Maoyun [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of pharmacy, Jinan University, Guangzhou (China); Xiang, Yangfei; Ma, Kaiqi [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); Jin, Fujun [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of pharmacy, Jinan University, Guangzhou (China); Wang, Xiao [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Wang, Xiaoyan; Wang, Shaoxiang [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); Wang, Yifei, E-mail: twang-yf@163.com [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China)

    2014-04-18

    Highlights: • We analyze the anti-HSV potential of chloride channel inhibitors. • Tamoxifen and NPPB show anti-HSV-1 and anti-ACV-resistant HSV-1 activities. • HSV-1 infection induces intracellular chloride concentration increasing. • Tamoxifen and NPPB inhibit HSV-1 early infection. • Tamoxifen and NPPB prevent the fusion process of HSV-1. - Abstract: Herpes simplex virus type 1 (HSV-1) infection is very common worldwide and can cause significant health problems from periodic skin and corneal lesions to encephalitis. Appearance of drug-resistant viruses in clinical therapy has made exploring novel antiviral agents emergent. Here we show that chloride channel inhibitors, including tamoxifen and 5-nitro-2-(3-phenyl-propylamino) benzoic acid (NPPB), exhibited extensive antiviral activities toward HSV-1 and ACV-resistant HSV viruses. HSV-1 infection induced chloride ion influx while treatment with inhibitors reduced the increase of intracellular chloride ion concentration. Pretreatment or treatment of inhibitors at different time points during HSV-1 infection all suppressed viral RNA synthesis, protein expression and virus production. More detailed studies demonstrated that tamoxifen and NPPB acted as potent inhibitors of HSV-1 early entry step by preventing viral binding, penetration and nuclear translocation. Specifically the compounds appeared to affect viral fusion process by inhibiting virus binding to lipid rafts and interrupting calcium homeostasis. Taken together, the observation that tamoxifen and NPPB can block viral entry suggests a stronger potential for these compounds as well as other ion channel inhibitors in antiviral therapy against HSV-1, especially the compound tamoxifen is an immediately actionable drug that can be reused for treatment of HSV-1 infections.

  15. 17beta-estradiol reduces the effect of metabolic inhibition on gap junction intercellular communication in rat cardiomyocytes via the estrogen receptor.

    Science.gov (United States)

    Chung, Tun-Hui; Wang, Seu-Mei; Wu, Jiahn-Chun

    2004-11-01

    The effects of 17beta-estradiol (E2) on gap junction intercellular communication (GJIC) were assessed by Lucifer yellow dye coupling in cultured neonatal rat cardiomyocytes after metabolic inhibition (MI) using potassium cyanide and sodium iodoacetate. MI significantly reduced dye coupling of cardiomyocytes to 8.5% +/- 0.6% of control levels, and pretreatment with E2, but not its inactive isomer 17alpha-estradiol, dose-dependently (EC(50) = 0.41 microM) increased the dye coupling up to 76% +/- 15% of control levels. The effect of E2 on MI-induced dye uncoupling was abolished by tamoxifen, a potent estrogen receptor (ER) antagonist. The ligand, E2-BSA-FITC, labeled the cardiomyocyte surface, whereas BSA-FITC did not, suggesting the presence of membrane-associated E2 receptors. Double immunofluorescence microscopy showed that MI-induced the accumulation of non-phosphorylated Cx43 at the gap junction and that this was prevented by E2 pretreatment. Labeling of Lucifer yellow-microinjected cardiomyocytes with antibodies specific for Ser368-phosphorylated Cx43 (Ser368Cx43) or non-phosphorylated Cx43 confirmed that E2 reduced the MI-induced inhibition of dye coupling and accumulation of non-phosphorylated Cx43 concomitant with the reappearance of Ser368Cx43 at the gap junction. MI caused a decrease in Ser368Cx43 protein levels, and pretreatment with E2 significantly increased the levels of Ser368Cx43. Inhibition of protein kinase C (PKC) with chelerythrine blocked the E2-induced increase of Ser368Cx43 levels in MI-treated cardiomyocytes. These results suggest that E2 attenuates the inhibitory effect of MI on GJIC in cardiomyocytes by affecting the phosphorylation of Cx43, possibly mediated by activation of PKC via a membrane-associated signaling mechanism.

  16. Comparison of in vivo and in vitro reporter gene assays for short-term screening of estrogenic activity

    NARCIS (Netherlands)

    Legler, J.; Zeinstra, L.M.; Schuitemaker, F.; Lanser, P.H.; Bogerd, J.; Brouwer, A.; Vethaak, A.D.; Voogt, de P.; Murk, A.J.; Burg, van der B.

    2002-01-01

    Functional in vitro and in vivo reporter gene assays have recently been developed for the rapid determination of exposure to (xeno)estrogens. The in vitro estrogen receptor (ER)-mediated chemically activated luciferase gene expression (ER-CALUX) assay uses T47D human breast cancer cells stably

  17. Survival and safety of exemestane versus tamoxifen after 2-3 years' tamoxifen treatment (Intergroup Exemestane Study): a randomised controlled trial

    DEFF Research Database (Denmark)

    Coombes, R C; Kilburn, L S; Snowdon, C F

    2007-01-01

    BACKGROUND: Early improvements in disease-free survival have been noted when an aromatase inhibitor is given either instead of or sequentially after tamoxifen in postmenopausal women with oestrogen-receptor-positive early breast cancer. However, little information exists on the long-term effects ...

  18. [Estrogens, progestins and blood lipids].

    Science.gov (United States)

    Tikkanen, M J

    1984-01-01

    Progestins and estrogens can affect blood lipids and, as a result, contribute to cardiovascular disease. Since the very first studies, scientists have treated progestins and estrogens separately instead of studying their combined effect. Studies have shown that oral contraceptives (OCs) increase the risk of heart attack and brain hemorrhage. Heart attacks are 3-4 times more likely to occur in women aged 25-49 who are using OCs than those who are not. The risk diminishes after use is discontinued, but women aged 40-49 with a long history of OC use remain twice as prone to heart attacks even after giving up these contraceptives. OCs can cause problems with clotting, resulting in coronary and other arterial complications, increasing atherogenic risk. The effect of steroids on clotting and blood pressure must be studied before it can be determined how cardiovascular disease can be prevented. The author advocates the use of natural and synthetic estrogens in small quantities. He recommends the following in particular: progestins of the pregnal series, desogestrel, and a combination of 19-nortestosterone and estrogen. Synthetic estrogens (mestronol, ethinylestradio) increase high density lipoprotein (HDL) cholesterol levels, and androgens reduce them. Except for desogestrel, currently available progestins are related to androgens. It was discovered in 1977 that progestins in the pregnal series can cause tumors in the breast glands of beagles. Synthetic estrogens increase triglyceride levels by accelerating very low density lipoprotein (VLDL) synthesis. Currently available OCs which contain fewer estrogens, do not affect triglyceride levels to any significant degree. Conjugated estrogens are widely used in Anglo-Saxon countries and can cause hypertriglyceridemia. All other estrogens used to treat symptoms of menopause increase HDL cholesterol and reduce atherogenic LDL cholesterol.

  19. Age, photoperiod and estrogen dependent variations in the shell gland and the expression of AVT in the ovary of Japanese quail.

    Science.gov (United States)

    Srivastava, Rashmi; Chaturvedi, Chandra Mohini

    2012-05-01

    Present work was undertaken to describe (i) age dependent (prepuberal-3, 4, 5 and 6 weeks old, puberal and actively laying 8 and 12 weeks old and aged 78 weeks old) (ii) photoperiodic response dependent (photosensitive and photorefractory) and sex steroid dependent (estradiol benzoate and its antagonist tamoxifen treated) variation in the ovary and shell gland activity of Japanese quail (Coturnix coturnix japonica). Further, in view of the role of neurohypophysial peptide arginine vasotocin (AVT) in many physiological processes including age/reproduction related oviposition, expression of ir-AVT was also monitored in the ovary of quail. All the parameters associated with histodifferentiation increased rapidly during the developing stages followed by a decrease in old age, which also increased in reproductively quiescent photorefractory birds following estradiol treatment and decreased in reproductively active photosensitive quail following tamoxifen treatment. Using AVT-specific antibody, expression of immunoreactive AVT (ir-AVT) observed in the ovary of photosensitive quail was not detected in the photorefractory quail. However, administration of estrogen in the photorefractory quail stimulated the growth and activity of ovary and shell gland also resulted in the expression of ovarian ir-AVT. On the other hand, tamoxifen eliminated the localization of ir-AVT in the ovary of photosensitive quail in addition to a decrease in the shell gland protein and alkaline phosphatase activity. It is concluded that estrogen not only affects the growth and differentiation of ovary and oviduct including shell gland but also regulates the expression of ovarian AVT. It is also suggested that in addition to reported paracrine effect of AVT in the shell gland of Japanese quail for oviposition, ovarian AVT may also affect ovarian function (ovulation), and in part, this regulation is estrogen dependent. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Perinatal Taurine Imbalance Followed by High Sugar Intake Alters the Effects of Estrogen on Renal Excretory Function in Adult Female Rats.

    Science.gov (United States)

    Roysommuti, Sanya; Lerdweeraphon, Wichaporn; Michael Wyss, J

    2017-01-01

    This study tests the hypothesis that perinatal taurine imbalance impairs renal function in adult female rats via alterations in estrogen activity. Female Sprague-Dawley rats were fed normal rat chow and water containing 3% beta-alanine (TD), 3% taurine (TS) or water alone (C) from conception until weaning. Then, female offspring received normal rat chow and water with (CG, TDG, TSG) or without (CW, TDW, TSW) 5% glucose. At 7-8 weeks of age, renal function at rest and after acute saline load was tested in conscious, restrained female rats treated with non-selective estrogen receptor blocker tamoxifen for a week. Compared to control, TD or TS did not affect mean arterial pressure (MAP). Tamoxifen significantly increased resting MAP only in TDG compared to TDW groups. Although renal blood flow did not significantly differ among the groups, renal vascular resistance increased in TSG compared to CW, CG, and TSW groups. Glomerular filtration rate and water and sodium excretion were not significantly different among the groups. Compared to CW, saline load significantly depressed fractional water excretion in CG, TDW, TDG, and TSW, and fractional sodium excretion in CG, TDW, TDG, TSW, and the TSG groups. Potassium excretion was not significantly different among the corresponding groups. Fractional potassium excretion significantly increased in TDW compared to CG and in TSG compared to CG and TSW groups. These differences were abolished by tamoxifen treatment. These data indicate that in adult female rats, perinatal taurine imbalance, particularly followed by high sugar intake, alters renal function via an estrogenic mechanism.

  1. Molecular conservation of estrogen-response associated with cell cycle regulation, hormonal carcinogenesis and cancer in zebrafish and human cancer cell lines.

    Science.gov (United States)

    Lam, Siew Hong; Lee, Serene G P; Lin, Chin Y; Thomsen, Jane S; Fu, Pan Y; Murthy, Karuturi R K; Li, Haixia; Govindarajan, Kunde R; Nick, Lin C H; Bourque, Guillaume; Gong, Zhiyuan; Lufkin, Thomas; Liu, Edison T; Mathavan, Sinnakaruppan

    2011-05-16

    The zebrafish is recognized as a versatile cancer and drug screening model. However, it is not known whether the estrogen-responsive genes and signaling pathways that are involved in estrogen-dependent carcinogenesis and human cancer are operating in zebrafish. In order to determine the potential of zebrafish model for estrogen-related cancer research, we investigated the molecular conservation of estrogen responses operating in both zebrafish and human cancer cell lines. Microarray experiment was performed on zebrafish exposed to estrogen (17β-estradiol; a classified carcinogen) and an anti-estrogen (ICI 182,780). Zebrafish estrogen-responsive genes sensitive to both estrogen and anti-estrogen were identified and validated using real-time PCR. Human homolog mapping and knowledge-based data mining were performed on zebrafish estrogen responsive genes followed by estrogen receptor binding site analysis and comparative transcriptome analysis with estrogen-responsive human cancer cell lines (MCF7, T47D and Ishikawa). Our transcriptome analysis captured multiple estrogen-responsive genes and signaling pathways that increased cell proliferation, promoted DNA damage and genome instability, and decreased tumor suppressing effects, suggesting a common mechanism for estrogen-induced carcinogenesis. Comparative analysis revealed a core set of conserved estrogen-responsive genes that demonstrate enrichment of estrogen receptor binding sites and cell cycle signaling pathways. Knowledge-based and network analysis led us to propose that the mechanism involving estrogen-activated estrogen receptor mediated down-regulation of human homolog HES1 followed by up-regulation cell cycle-related genes (human homologs E2F4, CDK2, CCNA, CCNB, CCNE), is highly conserved, and this mechanism may involve novel crosstalk with basal AHR. We also identified mitotic roles of polo-like kinase as a conserved signaling pathway with multiple entry points for estrogen regulation. The findings

  2. Molecular conservation of estrogen-response associated with cell cycle regulation, hormonal carcinogenesis and cancer in zebrafish and human cancer cell lines

    Directory of Open Access Journals (Sweden)

    Govindarajan Kunde R

    2011-05-01

    Full Text Available Abstract Background The zebrafish is recognized as a versatile cancer and drug screening model. However, it is not known whether the estrogen-responsive genes and signaling pathways that are involved in estrogen-dependent carcinogenesis and human cancer are operating in zebrafish. In order to determine the potential of zebrafish model for estrogen-related cancer research, we investigated the molecular conservation of estrogen responses operating in both zebrafish and human cancer cell lines. Methods Microarray experiment was performed on zebrafish exposed to estrogen (17β-estradiol; a classified carcinogen and an anti-estrogen (ICI 182,780. Zebrafish estrogen-responsive genes sensitive to both estrogen and anti-estrogen were identified and validated using real-time PCR. Human homolog mapping and knowledge-based data mining were performed on zebrafish estrogen responsive genes followed by estrogen receptor binding site analysis and comparative transcriptome analysis with estrogen-responsive human cancer cell lines (MCF7, T47D and Ishikawa. Results Our transcriptome analysis captured multiple estrogen-responsive genes and signaling pathways that increased cell proliferation, promoted DNA damage and genome instability, and decreased tumor suppressing effects, suggesting a common mechanism for estrogen-induced carcinogenesis. Comparative analysis revealed a core set of conserved estrogen-responsive genes that demonstrate enrichment of estrogen receptor binding sites and cell cycle signaling pathways. Knowledge-based and network analysis led us to propose that the mechanism involving estrogen-activated estrogen receptor mediated down-regulation of human homolog HES1 followed by up-regulation cell cycle-related genes (human homologs E2F4, CDK2, CCNA, CCNB, CCNE, is highly conserved, and this mechanism may involve novel crosstalk with basal AHR. We also identified mitotic roles of polo-like kinase as a conserved signaling pathway with multiple entry

  3. Urinary estrogen metabolites and self-reported infertility in women infected with Schistosoma haematobium.

    Directory of Open Access Journals (Sweden)

    Júlio Santos

    metabolic pathways. In view of the statistically significant association between catechol-estrogens/ DNA adducts and self-reported infertility, we propose that an estrogen-DNA adduct mediated pathway in S. haematobium-induced ovarian hormonal deregulation could be involved. In addition, the catechol-estrogens/ DNA adducts described here represent potential biomarkers for schistosomiasis haematobia.

  4. Estrogen and gastrointestinal malignancy.

    LENUS (Irish Health Repository)

    Hogan, A M

    2012-02-01

    The concept that E2 exerts an effect on the gastrointestinal tract is not new and its actions on intestinal mucosa have been investigated for at least three decades. An attempt to consolidate results of these investigations generates more questions than answers, thus suggesting that many unexplored avenues remain and that the full capabilities of this steroid hormone are far from understood. Evidence of its role in esophageal, gastric and gallbladder cancers is confusing and often equivocal. The most compelling evidence regards the protective role conferred by estrogen (or perhaps ERbeta) against the development and proliferation of colon cancer. Not only has the effect been described but also many mechanisms of action have been explored. It is likely that, along with surgery, chemotherapy and radiotherapy, hormonal manipulation will play an integral role in colon cancer management in the very near future.

  5. Effects of Gender and Estrogen Receptors on Iron-Induced Brain Edema Formation.

    Science.gov (United States)

    Xie, Qing; Xi, Guohua; Keep, Richard F; Hua, Ya

    2016-01-01

    Our previous studies have shown that female mice have less brain edema and better recovery in neurological deficits after intracerebral hemorrhage (ICH) and that 17β-estradiol treatment in male mice markedly reduces ICH-induced brain edema. In this study, we investigated the role of gender and the estrogen receptors (ERs) in iron-induced brain edema. There were three parts in this study: (1) either male or female mice received an injection of 10 μL FeCl2 (1 mM) into the right caudate; (2) females received an intracaudate injection of FeCl2 or saline with 1 μg of ICI 182,780 (antagonists of ERs) or vehicle; and (3) males were treated with the ER regulator tamoxifen (5 mg/kg subcutaneously) or vehicle 1 h after FeCl2 injection. Mice were euthanized 24 h later for brain edema determination. FeCl2 induced lower brain edema in females than in males. Co-injection of ICI 182,780 with FeCl2 aggravated iron-induced brain edema in female mice. ICI 182,780 itself did not induce brain edema at the dose of 1 μg. Tamoxifen treatment reduced FeCl2-induced brain edema in male mice. In conclusion, iron induced less brain edema in female mice than in males. ER modification can affect iron-induced brain edema.

  6. Hops (Humulus lupulus) inhibits oxidative estrogen metabolism and estrogen-induced malignant transformation in human mammary epithelial cells (MCF-10A).

    Science.gov (United States)

    Hemachandra, L P; Madhubhani, P; Chandrasena, R; Esala, P; Chen, Shao-Nong; Main, Matthew; Lankin, David C; Scism, Robert A; Dietz, Birgit M; Pauli, Guido F; Thatcher, Gregory R J; Bolton, Judy L

    2012-01-01

    Long-term exposure to estrogens including those in traditional hormone replacement therapy (HRT) increases the risk of developing hormone-dependent cancers. As a result, women are turning to over-the-counter (OTC) botanical dietary supplements, such as black cohosh (Cimicifuga racemosa) and hops (Humulus lupulus), as natural alternatives to HRT. The two major mechanisms which likely contribute to estrogen and/or HRT cancer risk are: the estrogen receptor-mediated hormonal pathway; and the chemical carcinogenesis pathway involving formation of estrogen quinones that damage DNA and proteins, hence initiating and promoting carcinogenesis. Because, OTC botanical HRT alternatives are in widespread use, they may have the potential for chemopreventive effects on estrogen carcinogenic pathways in vivo. Therefore, the effect of OTC botanicals on estrogen-induced malignant transformation of MCF-10A cells was studied. Cytochrome P450 catalyzed hydroxylation of estradiol at the 4-position leads to an o-quinone believed to act as the proximal carcinogen. Liquid chromatography/tandem mass spectrometry analysis of estradiol metabolites showed that 4-hydroxylation was inhibited by hops, whereas black cohosh was without effect. Estrogen-induced expression of CYP450 1B1 and CYP450 1A1 was attenuated by the hops extract. Two phenolic constituents of hops (xanthohumol, XH; 8-prenylnaringenin, 8-PN) were tested: 8-PN was a potent inhibitor, whereas XH had no effect. Finally, estrogen-induced malignant transformation of MCF-10A cells was observed to be significantly inhibited by hops (5 μg/mL) and 8-PN (50 nmol/L). These data suggest that hops extracts possess cancer chemopreventive activity through attenuation of estrogen metabolism mediated by 8-PN. ©2011 AACR.

  7. Hops (Humulus lupulus) inhibits Oxidative Estrogen Metabolism and Estrogen-Induced Malignant Transformation in Human Mammary Epithelial cells (MCF-10A)

    Science.gov (United States)

    Madhubhani, L.P.; Hemachandra, P.; Esala, R.; Chandrasena, P.; Chen, Shao-Nong; Main, Matthew; Lankin, David C.; Scism, Robert A.; Dietz, Birgit M.; Pauli, Guido F.; Thatcher, Gregory R. J.; Bolton, Judy L.

    2011-01-01

    Long-term exposure to estrogens including those in traditional hormone replacement therapy (HRT) increases the risk of developing hormone-dependent cancers. As a result, women are turning to over-the-counter (OTC) botanical dietary supplements such as black cohosh (Cimicifuga racemosa) and hops (Humulus lupulus) as natural alternatives to HRT. The two major mechanisms which likely contribute to estrogen and/or HRT cancer risk are: the estrogen receptor (ER) mediated hormonal pathway; and, the chemical carcinogenesis pathway involving formation of estrogen quinones that damage DNA and proteins, hence initiating and promoting carcinogenesis. Since OTC botanical HRT alternatives are in widespread use they may have the potential for chemopreventive effects on estrogen carcinogenic pathways in vivo. Therefore the effect of OTC botanicals on estrogen-induced malignant transformation of MCF-10A cells was studied. Cytochrome P450 catalyzed hydroxylation of estradiol at the 4-position leads to an o-quinone believed to act as the proximal carcinogen. LC-MS/MS analysis of estradiol metabolites showed that 4-hydroxylation was inhibited by hops, whereas black cohosh was without effect. Estrogen-induced expression of CYP450 1B1 and CYP450 1A1 was attenuated by the hops extract. Two phenolic constituents of hops (xanthohumol, XH; and 8-prenylnaringenin, 8-PN) were tested: 8-PN was a potent inhibitor whereas XH had no effect. Finally, estrogen-induced malignant transformation of MCF-10A cells was observed to be significantly inhibited by hops (5 μg/mL) and 8-PN (50 nM). These data suggest that hops extracts possess cancer chemopreventive activity through attenuation of estrogen metabolism mediated by 8-PN. PMID:21997247

  8. Inhibition of long non-coding RNA ROR reverses resistance to Tamoxifen by inducing autophagy in breast cancer.

    Science.gov (United States)

    Li, Yuehua; Jiang, Baohong; Zhu, Hongbo; Qu, Xiaofei; Zhao, Liqin; Tan, Yeru; Jiang, Yiling; Liao, Mingchu; Wu, Xiaoping

    2017-06-01

    This study explored the mechanism underlying long non-coding RNA ROR regulating autophagy on Tamoxifen resistance in breast cancer. Cancer tissues and adjacent normal tissues were collected from 74 breast cancer patients. Human breast cancer BT474 cells were assigned into blank, phosphate buffered saline, Tamoxifen, negative control + Tamoxifen, siROR + Tamoxifen, 3-methyladenine + Tamoxifen, and siROR + 3-methyladenine + TA groups. The expression of long non-coding RNA ROR and expressions of multi-drug resistance-associated P-glycoprotein and glutathione S-transferase-π messenger RNA were detected using quantitative real-time polymerase chain reaction. The expressions of light chain 3, Beclin 1, multi-drug resistance-associated P-glycoprotein, and glutathione S-transferase-π protein were determined using western blotting. Cell proliferation, invasion, and migration abilities were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Transwell assay, and scratch test, respectively. The long non-coding RNA ROR expression was higher in the breast cancer tissues than that in the adjacent normal tissues. Compared with the blank group, light chain 3 and Beclin 1 expressions were increased in the siROR + Tamoxifen group but decreased in the 3-methyladenine + Tamoxifen group; these data indicated that downregulated long non-coding RNA ROR promoted autophagy. In comparison with the blank group, multi-drug resistance-associated P-glycoprotein and glutathione S-transferase-π messenger RNA and protein expressions were reduced in the siROR + Tamoxifen group but elevated in the 3-methyladenine + Tamoxifen group, suggesting that downregulated long non-coding RNA ROR suppressed the drug resistance to Tamoxifen and the inhibition of autophagy reversed the effect of long non-coding RNA ROR on drug resistance. Compared with the Tamoxifen, negative control, and siROR + 3-methyladenine + Tamoxifen groups, the cell

  9. Haploinsufficiency of the corepressor of estrogen receptor activity (REA) enhances estrogen receptor function in the mammary gland.

    Science.gov (United States)

    Mussi, Paola; Liao, Lan; Park, Seong-Eun; Ciana, Paolo; Maggi, Adriana; Katzenellenbogen, Benita S; Xu, Jianming; O'Malley, Bert W

    2006-11-07

    Estrogen receptor (ER)-mediated gene expression plays an essential role in mammary gland morphogenesis, function, and carcinogenesis. The repressor of ER activity (REA) is an ER-interactive protein that counterbalances estrogen-induced ER transcriptional activity. Our previous study showed that genetic deletion of both REA alleles resulted in embryonic lethality. This study demonstrates that REA and ERalpha are coexpressed in mammary epithelial cells. REA heterozygous (REA(+/-)) mutant mice exhibit faster mammary ductal elongation in virgin animals, increased lobuloalveolar development during pregnancy, and delayed mammary gland involution after weaning. These morphological phenotypes of REA(+/-) mice are associated with significantly increased cell proliferation and ER transcriptional activities, as indicated by the estrogen response element (ERE)-luciferase reporter in the WT/ERE-Luc and REA(+/-)/ERE-Luc bigenic mice and by the higher expression levels of estrogen-responsive genes such as progesterone receptor and cyclin D1 in the mammary gland. Our analysis also revealed that REA is an important repressor of ER transcriptional activity in the mammary gland under natural, as well as ovariectomized and estrogen-replaced, hormonal conditions. Our results indicate that REA is a physiological modulator of ER function in the mammary gland and that its correct gene dosage is required for maintenance of normal ER activity and normal mammary gland development. Consequently, a reduction or loss of REA function may cause overactivation of ER and increase breast cancer risk in humans.

  10. Selective estrogen receptor modulators (SERM: A new choice for postmenopausal women and physicians who worry on cancer

    Directory of Open Access Journals (Sweden)

    Ali Baziad

    2001-09-01

    Full Text Available The postmenopausal state is characterized by the cessation of menstruation, loss of ovarian function, and a dramatic decrease in the level of circulating estrogen. This state of estrogen deficiency contributes to the acceleration of several age-related health problems in women, including cardiovascular disease, osteoporosis, and dementia. Estrogen replacement is clearly effective in the short-term and long-term treatment and prevention of postmenopausal symptoms. However, until now, the amount of HRT user is still very low. Fear of breast cancer and endometrial cancer are the most common concern in using hormone replacement therapy (HRT, although the relationship between long-term HRT and breast cancer remains controversial. For physicians or patients, who worry on cancer, the ideal drug is now available i.e. the selective estrogen receptor modulators (SERM, with the generic name raloxifine. (Med J Indones 2001; 10: 187-90Keywords: HRT, raloxifine, osteoporosis, CVD, tamoxifen

  11. Estrogen stimulates adenosine receptor expression subtypes in human breast cancer MCF-7 cell line.

    Science.gov (United States)

    Mohamadi, Azam; Aghaei, Mahmoud; Panjehpour, Mojtaba

    2018-02-01

    Estrogen is a steroid hormone that plays a key role in the development and regulation of reproductive system. It has been shown that estrogen is related to breast cancer development through binding to its receptors. In order to uncover the estrogen effects on adenosine receptor expression, estrogen-positive MCF-7 cells were used to treat with agonist and antagonist of estrogen and then the mRNA expression of adenosine receptor subtypes were evaluated. Estrogen-positive MCF-7 cells were treated with various concentrations of 17β estradiol (E2) as an estrogen agonist, and ICI 182,780 as an estrogen antagonist. The gene expression of adenosine receptor subtypes were detected by real time RT-PCR. The results of MTT assay showed that E2 increased cell viability in a dose dependent manner. The expression pattern of all adenosine receptor subtypes are as follow; A2b > A1 > A2a > A3 in untreated MCF-7 cells. Obtained results showed that E2 incubation at 0.001-0.01 μM led to up-regulation of A1ARs, A2aARs and A3ARs dose dependently. E2 at 0.001 μM also had no significant effect on A2bARs expression but, at higher doses induced a considerable decrease in mRNA A2bARs expression. Treatment with antagonist confirmed that up-regulation of these receptors is mediated by estrogen receptor. Taken together, our results indicate that treatment of MCF-7 cells with E2 led to up-regulation of adenosine receptors. However, these effects were partially restored by treatment with antagonist suggesting that such effects are mediated by estrogen receptors.

  12. Analysis of the Ki-67 index in the vaginal epithelium of castrated rats treated with tamoxifen

    Directory of Open Access Journals (Sweden)

    Afif Rieth Nery-Aguiar

    2016-02-01

    Full Text Available OBJECTIVES: Vaginal atrophy and breast cancer are common conditions in postmenopausal women and tamoxifen is the standard endocrine treatment for hormone-sensitive tumors. The present study aimed to assess the effect of tamoxifen on Ki-67 protein expression in the vaginal epithelium of castrated rats. MATERIAL AND METHODS: Forty Wistar-Hannover adult, virgin, castrated rats were randomly divided into two groups, group I (control, n=20 and group II (tamoxifen, n=20, receiving 0.5 ml of propylene glycol and 250 µg of tamoxifen diluted in 0.5 ml of propylene glycol, respectively, daily by gavage for 30 days. On the 31st day, the rats were euthanized and their vaginas were removed and fixed in 10% buffered formalin for the immunohistochemical study of Ki-67 protein expression. Data were analyzed by the Levene and Student’s t tests (p<0.05. RESULTS: The mean index of Ki-67 expression in the rat vagina of groups I and II was 4.04±0.96 and 26.86±2.19, respectively (p<0.001. CONCLUSIONS: According to the results of the present study, tamoxifen, at the dose and treatment length used, induced a significant increase in the cell proliferation of the vaginal mucosa in castrated rats, as evaluated by Ki-67 protein expression.

  13. Incidence of new primary cancers after adjuvant tamoxifen therapy and radiotherapy for early breast cancer

    International Nuclear Information System (INIS)

    Andersson, M.; Storm, H.H.; Mouridsen, H.T.

    1991-01-01

    The incidence of new primary cancers was evaluated in 3538 postmenopausal patients who had received surgical treatment for primary breast cancer. Of these patients, 1828 with a low risk of recurrence received no further treatment. High-risk patients were randomly assigned to one of two groups. The first group (n = 846) received postoperative radiotherapy, while the second group (n = 864) received radiotherapy plus tamoxifen at a dose of 30 mg given daily for 48 weeks. The median observation time was 7.9 years. In comparison with the number of new cancers in the general population, the number of new cancers in the three groups was elevated mostly due to a high number of cancers of the contralateral breast and of colorectal cancers in the high-risk groups. The cumulative risk of nonlymphatic leukemia was increased among patients who received postoperative radiotherapy (P = .04). Cancer incidence in the high-risk tamoxifen-treated group relative to that in the high-risk group not treated with tamoxifen was not significant (1.3). No protective effect of tamoxifen on the opposite breast was seen (rate ratio for breast cancer = 1.1), but a tendency to an elevated risk of endometrial cancer was observed (rate ratio = 3.3; 95% confidence interval = 0.6-32.4). Continued and careful follow-up of women treated with tamoxifen is necessary to clarify the potential cancer-suppressive or cancer-promoting effects of this drug

  14. Tamoxifen treatment for pubertal gynecomastia in two siblings with partial androgen insensitivity syndrome.

    Science.gov (United States)

    Saito, Reiko; Yamamoto, Yukiyo; Goto, Motohide; Araki, Shunsuke; Kubo, Kazuyasu; Kawagoe, Rinko; Kawada, Yasusada; Kusuhara, Koichi; Igarashi, Maki; Fukami, Maki

    2014-01-01

    Although tamoxifen has been shown to be fairly safe and effective for idiopathic pubertal gynecomastia, it remains unknown whether it is also beneficial for gynecomastia associated with endocrine disorders. Here, we report the effect of tamoxifen on pubertal gynecomastia in 2 siblings with partial androgen insensitivity syndrome (PAIS). Cases 1 and 2 presented with persistent pubertal gynecomastia at 13 and 16 years of age, respectively. Physical examinations revealed breast of Tanner stage 3 and normal male-type external genitalia in both cases. Clinical features such as female-type pubic hair and borderline small testis indicated mildly impaired masculinization. Molecular analysis identified a previously reported p.Arg789Ser mutation in the androgen receptor gene (AR) in the 2 cases. Two months of oral administration of tamoxifen ameliorated gynecomastia to Tanner stage 2 with no adverse events. Additional treatment with testosterone enanthate showed negligible effects on body hair and penile length. Hormone values of the 2 cases during tamoxifen treatment remained similar to those in previously reported untreated patients with PAIS. The results indicate that tamoxifen was effective in treating pubertal gynecomastia in these 2 patients with PAIS and may be considered as a therapeutic option in this situation pending further studies.

  15. DNA stabilization by the upregulation of estrogen signaling in BRCA gene mutation carriers

    Directory of Open Access Journals (Sweden)

    Suba Z

    2015-05-01

    Full Text Available Zsuzsanna Suba Surgical and Molecular Tumor Pathology Centre, National Institute of Oncology, Budapest, Hungary Abstract: Currently available scientific evidence erroneously suggests that mutagenic weakness or loss of the BRCA1/2 genes may liberate the proliferative effects of estrogen signaling, which provokes DNA damage and genomic instability. Conversely, BRCA mutation seems to be an imbalanced defect, crudely inhibiting the upregulation of estrogen receptor expression and liganded transcriptional activity, whereas estrogen receptor-repressor functions become predominant. In BRCA-proficient cases, estrogen signaling orchestrates the activity of cell proliferation and differentiation with high safety, while upregulating the expression and DNA-stabilizing impact of BRCA genes. In turn, BRCA proteins promote estrogen signaling by proper estrogen synthesis via CYP19 gene regulation and by induction of the appropriate expression and transcriptional activity of estrogen receptors. In this exquisitely organized regulatory system, the dysfunction of each player may jeopardize genome stability and lead to severe chronic diseases, such as cancer development. Female organs, such as breast, endometrium, and ovary, exhibiting regular cyclic proliferative activity are particularly vulnerable in case of disturbances in either estrogen signaling or BRCA-mediated DNA repair. BRCA mutation carrier women may apparently be healthy or exhibit clinical signs of deficient estrogen signaling in spite of hyperestrogenism. Even women who enjoy sufficient compensatory DNA-defending activities are at risk of tumor development because many endogenous and environmental factors may jeopardize the mechanisms of extreme compensatory processes. Natural estrogens have numerous benefits in tumor prevention and therapy even in BRCA mutation carriers. There are no toxic effects even in sky-high doses and all physiologic cellular functions are strongly upregulated, while malignant

  16. Biomarker Genes for Detecting Estrogenic Activity of Endocrine Disruptors via Estrogen Receptors

    Directory of Open Access Journals (Sweden)

    Hyun Yang

    2012-02-01

    Full Text Available Endocrine disruptors (EDs are compounds used in various industrial products, drugs, and cosmetics. They can be found in the environment and disturb the endocrine and reproductive systems, resulting in adverse effects to humans and wildlife such as birth defects and developmental disorders. Since several EDs have a structure similar to that of endogenous steroid hormones such as estrogens, they intend to have an affinity for steroid hormone receptors and alter hormone-mediated metabolism by binding to these receptors. EDs are therefore a global concern and assays should be developed to efficiently determine whether these compounds are detrimental to biological systems. Diverse experimental methods may help determine the endocrine disrupting potential of EDs and evaluate the adverse effects of a single and/or combination of these reagents. Currently, biomarkers have been employed to objectively measure EDs potency and understand the underlying mechanisms. Further studies are required to develop ideal screening methods and biomarkers to determine EDs potency at environmentally relevant concentrations. In this review, we describe the biomarkers for estrogenicity of EDs identified both in vitro and in vivo, and introduce a biomarker, cabindin-D9k (CaBP-9k, that may be used to assess estrogenic activity of EDs.

  17. Estrogen switches pure mucinous breast cancer to invasive lobular carcinoma with mucinous features.

    Science.gov (United States)

    Jambal, Purevsuren; Badtke, Melanie M; Harrell, J Chuck; Borges, Virginia F; Post, Miriam D; Sollender, Grace E; Spillman, Monique A; Horwitz, Kathryn B; Jacobsen, Britta M

    2013-01-01

    Mucinous breast cancer (MBC) is mainly a disease of postmenopausal women. Pure MBC is rare and augurs a good prognosis. In contrast, MBC mixed with other histological subtypes of invasive disease loses the more favorable prognosis. Because of the relative rarity of pure MBC, little is known about its cell and tumor biology and relationship to invasive disease of other subtypes. We have now developed a human breast cancer cell line called BCK4, in which we can control the behavior of MBC. BCK4 cells were derived from a patient whose poorly differentiated primary tumor was treated with chemotherapy, radiation and tamoxifen. Malignant cells from a recurrent pleural effusion were xenografted in mammary glands of a nude mouse. Cells from the solid tumor xenograft were propagated in culture to generate the BCK4 cell line. Multiple marker and chromosome analyses demonstrate that BCK4 cells are human, near diploid and luminal, expressing functional estrogen, androgen, and progesterone receptors. When xenografted back into immunocompromised cycling mice, BCK4 cells grow into small pure MBC. However, if mice are supplemented with continuous estradiol, tumors switch to invasive lobular carcinoma (ILC) with mucinous features (mixed MBC), and growth is markedly accelerated. Tamoxifen prevents the expansion of this more invasive component. The unexpected ability of estrogens to convert pure MBC into mixed MBC with ILC may explain the rarity of the pure disease in premenopausal women. These studies show that MBC can be derived from lobular precursors and that BCK4 cells are new, unique models to study the phenotypic plasticity, hormonal regulation, optimal therapeutic interventions, and metastatic patterns of MBC.

  18. Estrogen and Breast Cancer

    National Research Council Canada - National Science Library

    Russo, Jose

    2004-01-01

    .... MCFlOF cells is ER-alpha negative, although, they ER-beta positive that could indicate that the response of the cells to growth and form colonies in agar methocel could be mediated by this receptor...

  19. Tamoxifen does not inhibit the swell activated chloride channel in human neutrophils during the respiratory burst.

    Science.gov (United States)

    Ahluwalia, Jatinder

    2008-10-31

    Effective functioning of neutrophils relies upon electron translocation through the NADPH oxidase (NOX). The electron current generated (I(e)) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential in activated human neutrophils. Swelling activated chloride channels have been demonstrated in part to counteract the depolarisation generated by the NADPH oxidase I(e). In the present study, the effects of inhibitors of swell activated chloride channels on ROS production and on the swelling activated chloride conductance was investigated in activated human neutrophils. Tamoxifen (10 microM), a specific inhibitor for swell activated chloride channels in neutrophils, completely inhibited both the PMA and FMLP stimulated respiratory burst. This inhibition of the neutrophil respiratory burst was not due to the blocking effect of tamoxifen on the swelling activated chloride conductance in these cells. These results demonstrate that a tamoxifen insensitive swell activated chloride channel has important significance during the neutrophil respiratory burst.

  20. Synthesis and characterization of Tamoxifen citrate modified reduced graphene oxide nano sheets for breast cancer therapy.

    Science.gov (United States)

    Zhang, Yu-Jin; Li, Bao-An; Li, Zhao-Yuan; Xia, Ning; Yu, Hai-Ying; Zhang, Ya-Zhi

    2018-03-01

    Theranostic agents are of immense consideration in the current generation nanomedicine. In this study, we have developed a facile approach for the fabrication of Tamoxifen citrate modified nanosized reduced graphene oxide (nano-rGO) with more stability and low cytotoxicity. The prepared nano-rGO sheets were characterized using HR-TEM and AFM imaging techniques. Further, the cytotoxicity was assessed using MTT assay on female BALB/c nude mice MCF-7 cell lines. In addition, by means of continuous-wave near-infrared laser, cancer cells in vivo were significantly ablated because of the photothermal effect stimulated by tamoxifen modified nano-rGO. These results indicated that the prepared tamoxifen modified nano-rGO has the ability to apply in the photothermal therapy of breast cancers. Consequently, further exploration of photothermal therapeutics is desirable for the synthesis of novel nano materials with additional functionalities. Copyright © 2017. Published by Elsevier B.V.

  1. Photoperiod reverses the effects of estrogens on male aggression via genomic and nongenomic pathways

    OpenAIRE

    Trainor, Brian C.; Lin, Shili; Finy*, M. Sima; Rowland, Michael R.; Nelson, Randy J.

    2007-01-01

    Despite recent discoveries of the specific contributions of genes to behavior, the molecular mechanisms mediating contributions of the environment are understudied. We demonstrate that the behavioral effects of estrogens on aggression are completely reversed by a discrete environmental signal, day length. Selective activation of either estrogen receptor α or β decreases aggression in long days and increases aggression in short days. In the bed nucleus of the stria terminalis, one of several n...

  2. Central estrogenic pathways protect against the depressant action of acute nicotine on reflex tachycardia in female rats

    International Nuclear Information System (INIS)

    El-Mas, Mahmoud M.; Fouda, Mohamed A.; El-gowilly, Sahar M.; Saad, Evan I.

    2012-01-01

    We have previously shown that acute exposure of male rats to nicotine preferentially attenuates baroreceptor-mediated control of reflex tachycardia in contrast to no effect on reflex bradycardia. Here, we investigated whether female rats are as sensitive as their male counterparts to the baroreflex depressant effect of nicotine and whether this interaction is modulated by estrogen. Baroreflex curves relating reflex chronotropic responses evoked by i.v. doses (1–16 μg/kg) of phenylephrine (PE) or sodium nitroprusside (SNP), were constructed in conscious freely moving proestrus, ovariectomized (OVX), and estrogen (50 μg/kg/day s.c., 5 days)-replaced OVX (OVXE 2 ) rats. Slopes of the curves were taken as a measure of baroreflex sensitivity (BRS PE and BRS SNP ). Nicotine (100 μg/kg i.v.) reduced BRS SNP in OVX rats but not in proestrus or OVXE 2 rats. The attenuation of reflex tachycardia by nicotine was also evident in diestrus rats, which exhibited plasma estrogen levels similar to those of OVX rats. BRS PE was not affected by nicotine in all rat preparations. Experiments were then extended to determine whether central estrogenic receptors modulate the nicotine–BRS SNP interaction. Intracisteral (i.c.) treatment of OVX rats with estrogen sulfate (0.2 μg/rat) abolished the BRS SNP attenuating effect of i.v. nicotine. This protective effect of estrogen disappeared when OVX rats were pretreated with i.c. ICI 182,780 (50 μg/rat, selective estrogen receptor antagonist). Together, these findings suggest that central neural pools of estrogen receptors underlie the protection offered by E 2 against nicotine-induced baroreceptor dysfunction in female rats. -- Highlights: ► Estrogen protects against the depressant effect of nicotine on reflex tachycardia. ► The baroreflex response and estrogen status affect the nicotine–BRS interaction. ► The protection offered by estrogen is mediated via central estrogen receptors.

  3. Increased Lipiodol uptake in hepatocellular carcinoma possibly due to increased membrane fluidity by dexamethasone and tamoxifen

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Stephanie, E-mail: stephanie.becker@rouen.fnclcc.f [Department of Nuclear Medicine, Centre E. Marquis, F-35042 Rennes (France); INSERM U 991, Rennes, F-35033 France (France); European University of Brittany, F-35000 Rennes (France); Department of Nuclear Medicine, Centre H. Becquerel, F-76038 Rouen (France); Ardisson, Valerie; Lepareur, Nicolas [Department of Nuclear Medicine, Centre E. Marquis, F-35042 Rennes (France); INSERM U 991, Rennes, F-35033 France (France); European University of Brittany, F-35000 Rennes (France); Sergent, Odile [European University of Brittany, F-35000 Rennes (France); UPRES EA SeRAIC, IFR 140, University of Rennes 1, F-35043 Rennes (France); Bayat, Sahar [INSERM U936 Department of Biostatistics, CHRU Pontchaillou, F-35033 Rennes (France); Noiret, Nicolas [European University of Brittany, F-35000 Rennes (France); Ecole Nationale Superieure de Chimie de Rennes, UMR CNRS 6226, F-35708 Rennes (France); Gaboriau, Francois; Clement, Bruno [INSERM U 991, Rennes, F-35033 France (France); Boucher, Evelyne [INSERM U 991, Rennes, F-35033 France (France); Department of Medical Oncology, Centre E. Marquis, F-35042 Rennes (France); Raoul, Jean-Luc [INSERM U 991, Rennes, F-35033 France (France); European University of Brittany, F-35000 Rennes (France); Department of Medical Oncology, Centre E. Marquis, F-35042 Rennes (France); Garin, Etienne [Department of Nuclear Medicine, Centre E. Marquis, F-35042 Rennes (France); INSERM U 991, Rennes, F-35033 France (France); European University of Brittany, F-35000 Rennes (France)

    2010-10-15

    Introduction: Lipiodol is used as a vector for chemoembolization or internal radiotherapy in unresectable hepatocellular carcinomas (HCCs). The aim of this study is to improve the tumoral uptake of Lipiodol by modulating membrane fluidizing agents to optimize the effectiveness of Lipiodol vectorized therapy. Methods: The effect of dexamethasone and tamoxifen on membrane fluidity was studied in vitro by electron paramagnetic resonance applied to rat hepatocarcinoma cell line N1S1. The tumoral uptake of Lipiodol was studied in vivo on rats with HCC, which had been previously treated by dexamethasone and/or tamoxifen, after intra-arterial administration of {sup 99m}Tc-SSS-Lipiodol. Results: The two molecules studied here exhibit a fluidizing effect in vitro which appears dependent on time and dose, with a maximum fluidity obtained after 1 hr at concentrations of 20 {mu}M for dexamethasone and 200 nM for tamoxifen. In vivo, while the use of dexamethasone or tamoxifen alone tends to lead to increased tumoral uptake of Lipiodol, this effect does not reach levels of significance. On the other hand, there is a significant increase in the tumoral uptake of {sup 99m}Tc-SSS-Lipiodol in rats pretreated by both dexamethasone and tamoxifen, with a tumoral uptake (expressed in % of injected activity per g of tumor) of 13.57{+-}3.65% after treatment, as against 9.45{+-}4.44% without treatment (P<.05). Conclusions: Dexamethasone and tamoxifen fluidify the N1S1 cells membrane, leading to an increase in the tumoral uptake of Lipiodol. These drugs could be combined with chemo-Lipiodol-embolization or radiolabeled Lipiodol, with a view to improving the effectiveness of HCCs therapy.

  4. Effects of Topical Tamoxifen on Wound Healing of Burned Skin in Rats

    OpenAIRE

    Mehrvarz, Shaban; Ebrahimi, Ali; Sahraei, Hedayat; Bagheri, Mohammad Hasan; Fazili, Sima; Manoochehry, Shahram; Rasouli, Hamid Reza

    2017-01-01

    Background This study aimed to assess the effects of the topical application of tamoxifen on wound healing of burned skin in Wistar rats by evaluating 3 healing characteristics: fibrotic tissue thickness (FTT), scar surface area (SSA), and angiogenesis in the healed scar tissue. Methods Eighteen male Wistar rats were used in this study. A third-degree burn wound was made on the shaved animals’ back, measuring 2×2×2 cm. In the first group, a 2% tamoxifen ointment was applied to the wound twice...

  5. Principles of management of recurrence of breast cancer after tamoxifen therapy (abstract)

    International Nuclear Information System (INIS)

    Rasool, I.

    1999-01-01

    The management of recurrence of breast cancer after Tamoxifen therapy needs special attention. The recurrence can be local or distant. The patient, should be thoroughly investigated to find out exact sites of recurrences. Local recurrence is managed by excision, skin grafting or various types of flaps. If extensive radiation is administrated or if not given previously. The distant recurrence in patients who have had adjuvant menopausal status, sites of recurrence while life threatening or not and previous response. The patients who are post menopausal have responded to previous Tamoxifen therapy, long DFI and soft tissues and bony metastasis are best managed by Aromatase inhibitors i.e. Letrozole. (author)

  6. Apolipoprotein D expression does not predict breast cancer recurrence among tamoxifen-treated patients

    DEFF Research Database (Denmark)

    Klebaner, Daniella; Hamilton-Dutoit, Stephen; Ahern, Thomas P

    2017-01-01

    confounding using logistic regression. RESULTS: Cytoplasmic ApoD expression was seen in 68% of ER+ tumors, in 66% of ER- tumors, and in 66% of controls across both groups. In women with ER+ tumors, the associations of cytoplasmic ApoD expression with recurrence (OR = 1.0; 95% CI = 0.7 to 1.4) and increasing...... in tamoxifen-treated patients. IMPACT: This study eliminates the previously suggested marker ApoD as a predictor of recurrence among tamoxifen-treated women....

  7. G Protein-Coupled Estrogen Receptor-Selective Ligands Modulate Endometrial Tumor Growth

    Directory of Open Access Journals (Sweden)

    Whitney K. Petrie

    2013-01-01

    Full Text Available Endometrial carcinoma is the most common cancer of the female reproductive tract. GPER/GPR30 is a 7-transmembrane spanning G protein-coupled receptor that has been identified as the third estrogen receptor, in addition to ERα and ERβ. High GPER expression is predictive of poor survival in endometrial and ovarian cancer, but despite this, the estrogen-mediated signaling pathways and specific estrogen receptors involved in endometrial cancer remain unclear. Here, employing ERα-negative Hec50 endometrial cancer cells, we demonstrate that GPER mediates estrogen-stimulated activation of ERK and PI3K via matrix metalloproteinase activation and subsequent transactivation of the EGFR and that ER-targeted therapeutic agents (4-hydroxytamoxifen, ICI182,780/fulvestrant, and Raloxifene, the phytoestrogen genistein, and the “ERα-selective” agonist propylpyrazole triol also function as GPER agonists. Furthermore, xenograft tumors of Hec50 cells yield enhanced growth with G-1 and estrogen, the latter being inhibited by GPER-selective pharmacologic antagonism with G36. These results have important implications with respect to the use of putatively ER-selective ligands and particularly for the widespread long-term use of “ER-targeted” therapeutics. Moreover, our findings shed light on the potential mechanisms of SERM/SERD side effects reported in many clinical studies. Finally, our results provide the first demonstration that pharmacological inhibition of GPER activity in vivo prevents estrogen-mediated tumor growth.

  8. Estrogen receptor targeted contrast agents for molecular magnetic resonance imaging of breast cancer hormonal status

    Directory of Open Access Journals (Sweden)

    Adi ePais

    2016-04-01

    Full Text Available The estrogen receptor α (ER is over expressed in most breast cancers and its level serves as a major prognostic factor. It is important to develop quantitative molecular imaging methods that specifically detect ER in vivo and assess its function throughout the entire primary breast cancer, as well as in metastatic breast cancer lesions. This study presents the biochemical and molecular features, as well as the magnetic resonance imaging effects of two novel ER- targeted contrast agents (CAs based on pyridine-tetra-acetate-Gd(III chelate conjugated to 17β-estradiol (EPTA-Gd or to tamoxifen (TPTA-Gd. The experiments were conducted in solution, in human breast cancer cells and in severe combined immunodeficient mice implanted with transfected ER-positive and ER-negative MDA-MB-231 human breast cancer xenografts. Binding studies with ER in solution and in human breast cancer cells indicated affinities in the micromolar range of both CAs. Biochemical and molecular studies in breast cancer cell cultures showed that both CAs exhibit estrogen like agonistic activity, enhancing cell proliferation, as well as up-regulating cMyc oncogene and down-regulating ER expression levels. The MRI longitudinal relaxivity was significantly augmented by EPTA-Gd in ER-positive cells as compared to ER-negative cells. Dynamic contrast enhanced studies with EPTA-Gd in vivo indicated specific augmentation of the MRI water signal in the ER-positive versus ER-negative xenografts, confirming EPTA-Gd specific interaction with ER. In contrast, TPTA-Gd did not show increased enhancement in ER-positive tumors and did not appear to interact in vivo with the tumors’ ER. However, TPTA-Gd was found to interact strongly with muscle tissue, enhancing muscle signal intensity in a mechanism independent of the presence of ER. The specificity of EPTA-Gd interaction with ER in vivo was further verified by acute and chronic competition with tamoxifen. The chronic tamoxifen treatment also

  9. Epigenetic regulation of estrogen-dependent memory

    Science.gov (United States)

    Fortress, Ashley M.; Frick, Karyn M.

    2014-01-01

    Hippocampal memory formation is highly regulated by post-translational histone modifications and DNA methylation. Accordingly, these epigenetic processes play a major role in the effects of modulatory factors, such as sex steroid hormones, on hippocampal memory. Our laboratory recently demonstrated that the ability of the potent estrogen 17β-estradiol (E2) to enhance hippocampal-dependent novel object recognition memory in ovariectomized female mice requires ERK-dependent histone H3 acetylation and DNA methylation in the dorsal hippocampus. Although these data provide valuable insight into the chromatin modifications that mediate the memory-enhancing effects of E2, epigenetic regulation of gene expression is enormously complex. Therefore, more research is needed to fully understand how E2 and other hormones employ epigenetic alterations to shape behavior. This review discusses the epigenetic alterations shown thus far to regulate hippocampal memory, briefly reviews the effects of E2 on hippocampal function, and describes in detail our work on epigenetic regulation of estrogenic memory enhancement. PMID:24878494

  10. Potential mechanisms underlying estrogen-induced expression of the molluscan estrogen receptor (ER) gene

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Thi Kim Anh [School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308 (Australia); Department of Agriculture, Forestry and Fisheries, Vinh University, 182 Le Duan St., Vinh City, Nghe An (Viet Nam); MacFarlane, Geoff R. [School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308 (Australia); Kong, Richard Yuen Chong [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region (China); O’Connor, Wayne A. [New South Wales Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, NSW 2316 (Australia); Yu, Richard Man Kit, E-mail: Richard.Yu@newcastle.edu.au [School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308 (Australia)

    2016-10-15

    Highlights: • This is the first report on the putative promoter sequence of a molluscan ER gene. • The gene promoter contains putative binding sites for direct and indirect interaction with ER. • E2 upregulates ER gene expression in the ovary in vitro and in vivo. • E2-induced gene expression may require a novel ligand-dependent receptor. • The ER proximal promoter is hypomethylated regardless of gene expression levels. - Abstract: In vertebrates, estrogens and estrogen mimicking chemicals modulate gene expression mainly through a genomic pathway mediated by the estrogen receptors (ERs). Although the existence of an ER orthologue in the mollusc genome has been known for some time, its role in estrogen signalling has yet to be deciphered. This is largely due to its constitutive (ligand-independent) activation and a limited mechanistic understanding of its regulation. To fill this knowledge gap, we cloned and characterised an ER cDNA (sgER) and the 5′-flanking region of the gene from the Sydney rock oyster Saccostrea glomerata. The sgER cDNA is predicted to encode a 477-amino acid protein that contains a DNA-binding domain (DBD) and a ligand-binding domain (LBD) typically conserved among both vertebrate and invertebrate ERs. A comparison of the sgER LBD sequence with those of other ligand-dependent ERs revealed that the sgER LBD is variable at several conserved residues known to be critical for ligand binding and receptor activation. Ligand binding assays using fluorescent-labelled E2 and purified sgER protein confirmed that sgER is devoid of estrogen binding. In silico analysis of the sgER 5′-flanking sequence indicated the presence of three putative estrogen responsive element (ERE) half-sites and several putative sites for ER-interacting transcription factors, suggesting that the sgER promoter may be autoregulated by its own gene product. sgER mRNA is ubiquitously expressed in adult oyster tissues, with the highest expression found in the ovary

  11. Tamoxifen in the Mouse Brain: Implications for Fate-Mapping Studies Using the Tamoxifen-Inducible Cre-loxP System

    Czech Academy of Sciences Publication Activity Database

    Valný, Martin; Honsa, Pavel; Kirdajová, Denisa; Kameník, Zdeněk; Anděrová, Miroslava

    2016-01-01

    Roč. 10, ost (2016), s. 243 ISSN 1662-5102 R&D Projects: GA ČR(CZ) GA16-10214S; GA ČR(CZ) GA15-02760S Institutional support: RVO:68378041 ; RVO:61388971 Keywords : tamoxifen * brain metabolism * fate-mapping Subject RIV: FH - Neurology; EE - Microbiology, Virology (MBU-M) Impact factor: 4.555, year: 2016

  12. Mixture interactions of xenoestrogens with endogenous estrogens.

    Science.gov (United States)

    There is growing concern of exposure to fish, wildlife, and humans to water sources contaminated with estrogens and the potential impact on reproductive health. These environmental estrogens originate from various sources including concentrated animal feedlot operations (CAFO), m...

  13. Membrane-initiated actions of estrogens in neuroendocrinology: emerging principles.

    Science.gov (United States)

    Vasudevan, Nandini; Pfaff, Donald W

    2007-02-01

    Hormonal ligands for the nuclear receptor superfamily have at least two interacting mechanisms of action: 1) classical transcriptional regulation of target genes (genomic mechanisms); and 2) nongenomic actions that are initiated at the cell membrane, which could impact transcription. Although transcriptional mechanisms are increasingly well understood, membrane-initiated actions of these ligands are incompletely understood. Historically, this has led to a considerable divergence of thought in the molecular endocrine field. We have attempted to uncover principles of hormone action that are relevant to membrane-initiated actions of estrogens. There is evidence that the membrane-limited actions of hormones, particularly estrogens, involve the rapid activation of kinases and the release of calcium. Membrane actions of estrogens, which activate these rapid signaling cascades, can also potentiate nuclear transcription. These signaling cascades may occur in parallel or in series but subsequently converge at the level of modification of transcriptionally relevant molecules such as nuclear receptors and/or coactivators. In addition, other hormones or neurotransmitters may also activate cascades to crosstalk with estrogen receptor-mediated transcription. The idea of synergistic coupling between membrane-initiated and genomic actions of hormones fundamentally revises the paradigms of cell signaling in neuroendocrinology.