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Azizian H, Khaksari M, Asadikaram G, Sepehri G, Najafipour H. Therapeutic effects of tamoxifen on metabolic parameters and cytokines modulation in rat model of postmenopausal diabetic cardiovascular dysfunction: Role of classic estrogen receptors. Int Immunopharmacol 2018; 65:190-198. [PMID: 30316077 DOI: 10.1016/j.intimp.2018.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 09/29/2018] [Accepted: 10/05/2018] [Indexed: 12/25/2022]
Abstract
In postmenopausal women, the risk of diabetic cardiovascular disease drastically increases compared with that of premenopausal women. In the present study we surveyed the effects of Tamoxifen (TAM) and 17-β-estradiol (E2) on diabetic cardiovascular dysfunction. Female wistar rats were divided into six groups: sham-control, Diabetes, Ovariectomized (OVX) + Diabetes, OVX + Diabetes + Vehicle, OVX + Diabetes + E2, OVX + Diabetes + TAM. Type 2 diabetes was induced by High Fat Diet and low doses of STZ. E2 and TAM were administrated every four days for four weeks. Results show that, TAM or E2 reduces cardiac weight, atherogenic and cardiac risk indices. Mean arterial blood pressure (MABP) increased in diabetes group, while TAM and E2 prevented MABP increment. Also, fasting blood glucose was decreased by TAM and E2. Significant decrement in the level of IL-10 was observed in diabetes group and this effect was abolished by TAM and E2. Also, treatment with TAM and E2 resulted in improved inflammatory balance in favor of anti-inflammation. Although diabetes resulted in, increment of TC and LDL, TAM and E2 reduced lipids profile. Furthermore, treatment with TAM prevented the reduction of estrogen receptors (ERs) α and β protein levels, but its effect on the ERβ protein level was higher. Our results indicated that TAM protects against diabetic cardiovascular dysfunction and is a good candidate for E2 substitution.
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Affiliation(s)
- Hossein Azizian
- Department of Physiology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran; Department of Physiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Khaksari
- Endocrinology and Metabolism Research, and Physiology Research Centers, Kerman University of Medical Sciences, Kerman, Iran.
| | - Gholamreza Asadikaram
- Department of Biochemistry, and Metabolism & Endocrinology Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Gholamreza Sepehri
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman Univerity of Medical Sciences, Kerman, Iran
| | - Hamid Najafipour
- Physiology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
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Gingery A, Iwaniec UT, Subramaniam M, Turner RT, Pitel KS, McGovern RM, Reid JM, Marler RJ, Ingle JN, Goetz MP, Hawse JR. Skeletal and Uterotrophic Effects of Endoxifen in Female Rats. Endocrinology 2017; 158:3354-3368. [PMID: 28977607 PMCID: PMC5659691 DOI: 10.1210/en.2016-1871] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 07/31/2017] [Indexed: 12/24/2022]
Abstract
Endoxifen, the primary active metabolite of tamoxifen, is currently being investigated as a novel endocrine therapy for the treatment of breast cancer. Tamoxifen is a selective estrogen receptor modulator that elicits potent anti-breast cancer effects. However, long-term use of tamoxifen also induces bone loss in premenopausal women and is associated with an increased risk of endometrial cancer in postmenopausal women. For these reasons, we have used a rat model system to comprehensively characterize the impact of endoxifen on the skeleton and uterus. Our results demonstrate that endoxifen elicits beneficial effects on bone in ovary-intact rats and protects against bone loss following ovariectomy. Endoxifen is also shown to reduce bone turnover in both ovary-intact and ovariectomized rats at the cellular and biochemical levels. With regard to the uterus, endoxifen decreased uterine weight but maintained luminal epithelial cell height in ovariectomized animals. Within luminal epithelial cells, endoxifen resulted in differential effects on the expression levels of estrogen receptors α and β as well as multiple other genes previously implicated in regulating epithelial cell proliferation and hypertrophy. These studies analyze the impact of extended endoxifen exposure on both bone and uterus using a Food and Drug Administration-recommended animal model. Although endoxifen is a more potent breast cancer agent than tamoxifen, the results of the present study demonstrate that endoxifen does not induce bone loss in ovary-intact rats and that it elicits partial agonistic effects on the uterus and skeleton in ovariectomized animals.
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Affiliation(s)
- Anne Gingery
- Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Urszula T. Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331
| | - Malayannan Subramaniam
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Russell T. Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331
| | - Kevin S. Pitel
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Renee M. McGovern
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905
| | - Joel M. Reid
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905
- Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905
| | - Ronald J. Marler
- Department of Comparative Medicine, Mayo Clinic, Scottsdale, Arizona 85259
| | - James N. Ingle
- Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905
| | | | - John R. Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
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Al Naib A, Tucker H, Xie G, Keisler D, Bartol F, Rhoads R, Akers R, Rhoads M. Prepubertal tamoxifen treatment affects development of heifer reproductive tissues and related signaling pathways. J Dairy Sci 2016; 99:5780-5792. [DOI: 10.3168/jds.2015-10679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/02/2016] [Indexed: 11/19/2022]
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Mahran YF, El-Demerdash E, Nada AS, Ali AA, Abdel-Naim AB. Insights into the protective mechanisms of tamoxifen in radiotherapy-induced ovarian follicular loss: impact on insulin-like growth factor 1. Endocrinology 2013; 154:3888-99. [PMID: 23798597 DOI: 10.1210/en.2013-1214] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Radiotherapy is one of the most common and effective cancer treatments. However, it has a profound impact on ovarian function, leading to premature ovarian failure. With the hope of preserving fertility in cancer survivors, the need for an effective radioprotective therapy is evident. The present study investigated the mechanism of the potential radioprotective effect of tamoxifen (TAM) on γ-irradiation-induced ovarian failure on experimental rats and the impact of the IGF-1 in the underlying protective mechanisms. Female Sprague Dawley rats were either exposed to single whole-body irradiation (3.2 Gy; lethal dose [LD₂₀]) and/or treated with TAM (1 mg/kg). γ-Irradiation caused an array of ovarian dysfunction that was evident by assessment of hormonal changes, follicular development, proliferation marker (proliferating cell nuclear antigen), and oxidative stress as well as apoptotic markers. In addition, IGF-1/IGF-1 receptor axis expression was assessed using real-time RT-PCR and immunolocalization techniques. Furthermore, fertility assessment was performed. TAM significantly enhanced follicular development and restored the anti-Mullerian hormone level. Moreover, it ameliorated the deleterious effects of irradiation on oxidative stress, proliferating cell nuclear antigen expression, and apoptosis. Interestingly, TAM was shown to enhance the ovarian IGF-1 but not IGF-1 receptor, a property that contributed significantly to its radioprotective mechanisms. Finally, TAM regained the fertility that was lost after irradiation. In conclusion, TAM showed a radioprotective effect and saved the ovarian reserve and fertility through increasing anti-Mullerian hormone and the local IGF-1 level and counteracting the oxidative stress-mediated apoptosis.
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Affiliation(s)
- Yasmen F Mahran
- Professor of Pharmacology and Toxicology, Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Abasia, Cairo, Egypt. or
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Autocrine human growth hormone expression leads to resistance of MCF-7 cells to tamoxifen. Med Oncol 2009; 27:474-80. [PMID: 19472088 DOI: 10.1007/s12032-009-9237-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 05/14/2009] [Indexed: 12/11/2022]
Abstract
Tamoxifen is the most common antiestrogen used in the treatment of estrogen-positive breast cancer but its adverse effects and also resistance to this drug are serious challenges in the treatment of breast cancer. Characterization of mechanisms responsible for these adverse effects can lead to design of more efficient therapeutic strategies for the treatment of breast cancer. Here, we used a cellular model to evaluate the effects of autocrine expression of human growth hormone on responses of cells to tamoxifen. Our results imply for the first time that autocrine expression of growth hormone in human breast adenocarcinoma cell line, MCF-7, results in increase in cell proliferative capacity of cells even in the presence of tamoxifen. This effect may be due to up-regulation of G-coupled estrogen receptor, GPR30, which is activated by tamoxifen.
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Dowers TS, Qin ZH, Thatcher GRJ, Bolton JL. Bioactivation of Selective Estrogen Receptor Modulators (SERMs). Chem Res Toxicol 2006; 19:1125-37. [PMID: 16978016 PMCID: PMC2517576 DOI: 10.1021/tx060126v] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tamara S Dowers
- Department of Medicinal Chemistry and Pharmacognosy (M/C 781), College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612-7231, USA
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Ramachandran C, Khatib Z, Petkarou A, Fort J, Fonseca HB, Melnick SJ, Escalon E. Tamoxifen modulation of etoposide cytotoxicity involves inhibition of protein kinase C activity and insulin-like growth factor II expression in brain tumor cells. J Neurooncol 2004; 67:19-28. [PMID: 15072444 DOI: 10.1023/b:neon.0000021738.77612.1b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tamoxifen, a non-steroidal anti-estrogen widely used against breast cancer, is also useful for treatment of other malignancies, due to its sensitizing effect on other chemotherapeutic agents and radiation. We have investigated the advantages of combining tamoxifen with one of the commonly used cancer chemotherapeutic drug, etoposide (VP-16) in brain tumor cell lines. While tamoxifen (10 microM) increased etoposide cytotoxicity 8.3-fold in the human glioma cell line (HTB-14), it increased etoposide cytotoxicity 47.5- and 40-fold in two primary cell lines established from pediatric medulloblastoma patients (MCH-BT-31 and MCH-BT-39), respectively. Similarly, in the pediatric ependymoma cell lines (MCH-BT-30 and MCH-BT-52), tamoxifen enhanced etoposide cytotoxicity 6- and 2.68-fold, respectively. CalcuSyn analysis of cytotoxicity data showed that tamoxifen and etoposide combinations were synergistic with combination index values ranging from 0.243 to 0.369 at IC50 level among different pediatric brain tumor cell lines. Tamoxifen is also cytotoxic at higher concentrations (> 20 microM) in brain tumor cells. To understand the mechanism underlying the tamoxifen modulation of etoposide cytotoxicity, we analyzed expression of P-glycoprotein (P-gp), insulin-like growth factor-I receptor (IGF-IR), IGF-I, IGF-II and estrogen receptor as well as protein kinase C (PKC) activity. While P-gp, IGF-IR and IGF-I were not affected, enhanced inhibition of PKC, and IGF-II were observed in brain tumor cells treated with tamoxifen and etoposide combination as compared to cells treated with either drug alone. Tamoxifen at 10 microM when combined with etoposide at 0-100 microM concentrations reduced PKC activity 77% compared to only 58% without tamoxifen. IGF-II expression decreased to 48.6% of the untreated control in the combination treatment as compared to 31.2% for etoposide alone and 26.2% for tamoxifen alone treatments. These results suggest that inhibitory effect of tamoxifen on brain tumor cells manifest through different mechanisms involving inhibition of targets such as PKC and IGF-II.
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Stygar D, Muravitskaya N, Eriksson B, Eriksson H, Sahlin L. Effects of SERM (selective estrogen receptor modulator) treatment on growth and proliferation in the rat uterus. Reprod Biol Endocrinol 2003; 1:40. [PMID: 12777179 PMCID: PMC156658 DOI: 10.1186/1477-7827-1-40] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2003] [Accepted: 05/07/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Selective estrogen receptor modulators (SERMs) have been developed in order to create means to control estrogenic effects on different tissues. A major drawback in treatment of estrogen receptor (ER) positive breast cancer with the antagonist tamoxifen (TAM) is its agonistic effect in the endometrium. Raloxifene (RAL) is the next generation of SERMs where the agonistic effect on the endometrium has been reduced. METHODS The aim of the present study was to determine the effect of SERM treatment on the uterus, as assessed by proliferation markers and several factors involved in uterine growth. Ovariectomized (ovx) rats were treated with estradiol (E2), tamoxifen (TAM), RAL, ICI182780 (ICI) or vehicle (OVX-controls). We studied the effects on mRNA levels of the growth hormone (GH) receptor, insulin-like growth factor-I (IGF-I), ERalpha and ERbeta. In addition, by immunohistochemistry the proliferation markers PCNA and Ki-67, as well as ERalpha and ERbeta, were detected. RESULTS The uterine weight of the rats treated with E2 or TAM was increased as compared to OVX-controls. The uterine GH-receptor mRNA level was highest in the E2 treated animals. In ICI treated rats no GH-receptor mRNA could be detected. The IGF-I mRNA level increased 16-fold in uteri of the TAM treated group and 9-fold in the E2 treated rats as compared to OVX-controls. The ERalpha mRNA level was increased in the E2 treated rats, while the ERbeta mRNA level was increased after TAM treatment. The proliferation, as assessed by PCNA, was lowest in ICI treated animals. CONCLUSIONS The uterine wet weight, the LE height and the GH-receptor mRNA levels showed similar patterns, indicating that GH is involved in the regulation of uterine weight. Tamoxifen, which has been related to increased incidence of endometrial carcinoma in women, dramatically increased IGF-I mRNA levels in rat uterus. Since proliferation was not higher in TAM and E2 treated rats than in OVX controls, this assay of simple, early proliferation does not give the full explanation of why TAM should enhance the risk of developing endometrial cancer.
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Affiliation(s)
- Denis Stygar
- Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Natalia Muravitskaya
- Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Britt Eriksson
- Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Håkan Eriksson
- Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden
| | - Lena Sahlin
- Division for Reproductive Endocrinology, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden
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Conroy AT, Sharma M, Holtz AE, Wu C, Sun Z, Weigel RJ. A novel zinc finger transcription factor with two isoforms that are differentially repressed by estrogen receptor-alpha. J Biol Chem 2002; 277:9326-34. [PMID: 11779858 DOI: 10.1074/jbc.m107702200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Estrogen receptor-alpha (ERalpha) can induce the expression of genes in response to estrogen by binding to estrogen response elements in the promoters of target genes. There is growing evidence that ERalpha can alter patterns of gene expression in response to ligand by regulating the activity of other factors through a direct protein-protein interaction. To identify other factors that are regulated by ERalpha, a yeast two-hybrid screen was performed that identified a novel Cys(2)His(2) zinc finger protein named ZER6. The ZER6 protein contains a Kruppel-associated box domain and six Cys(2)His(2) zinc fingers. Transcripts from the ZER6 gene can have alternate 5' exons and encode either a p71 or p52 isoform. The p52-ZER6 protein interacts strongly with ERalpha in the presence of 17beta-estradiol, whereas the p71-ZER6 isoform has a HUB-1 amino-terminal domain that inhibits the interaction with ERalpha. A consensus ZER6 binding element was defined using PCR-assisted binding site selection. In COS-1 cells, both the p52 and p71 isoforms can activate transcription through the ZER6 binding element; however, in the presence of ERalpha, transactivation by the p52 isoform is specifically repressed. Overexpression of the p52 isoform was able to abrogate activation by p71-ZER6. Expression of ZER6 was largely restricted to the mammary gland with a lower level of expression in the kidney. We conclude that ZER6 is a novel zinc finger transcription factor in which regulation of transcription in hormone-responsive cells can be controlled by the relative level of expression of two distinct isoforms.
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Affiliation(s)
- Andrew T Conroy
- Department of Surgery, Stanford University School of Medicine, Stanford, California 94305, USA
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