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Lin AL, Geer EB, Lala N, Page-Wilson G, Magge R, Young RJ, Tabar V. The treatment of aggressive prolactinomas with everolimus. Pituitary 2023; 26:474-481. [PMID: 37428396 PMCID: PMC10765418 DOI: 10.1007/s11102-023-01340-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/03/2023] [Indexed: 07/11/2023]
Abstract
INTRODUCTION Aggressive prolactinomas are life-limiting tumors without a standard of care treatment option after the oral alkylator, temozolomide, fails to provide tumor control. METHODS We reviewed an institutional database of pituitary tumors for patients with aggressive prolactinomas who progressed following treatment with a dopamine receptor agonist, radiotherapy and temozolomide. Within this cohort, we identified four patients who were treated with everolimus and we report their response to this therapy. Treatment response was determined by a neuroradiologist, who manually performed volumetric assessment and determined treatment response by Response Assessments in Neuro-Oncology (RANO) criteria. RESULTS Three of four patients who were treated with everolimus had a biochemical response to therapy and all patients derived a clinically meaningful benefit based upon suppression of tumor growth. While the best overall response as assessed by RANO criteria was stable disease for the four patients, a minor regression in tumor size was appreciated in two of the four patients. CONCLUSION Everolimus is an active agent in the treatment of prolactinomas that warrants further investigation.
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Affiliation(s)
- Andrew L Lin
- Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Neurology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
- Multidisciplinary Pituitary and Skull Base Tumor Center, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA.
| | - Eliza B Geer
- Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Multidisciplinary Pituitary and Skull Base Tumor Center, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nupur Lala
- Department of Neurology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | | | - Rajiv Magge
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
| | - Robert J Young
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Viviane Tabar
- Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Multidisciplinary Pituitary and Skull Base Tumor Center, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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TRH Regulates the Synthesis and Secretion of Prolactin in Rats with Adenohypophysis through the Differential Expression of miR-126a-5p. Int J Mol Sci 2022; 23:ijms232415914. [PMID: 36555554 PMCID: PMC9781503 DOI: 10.3390/ijms232415914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 12/16/2022] Open
Abstract
Prolactin (PRL) is an important hormone that is secreted by the pituitary gland and plays an important role in the growth, development and reproduction of organisms. Thyrotropin-releasing hormone (TRH) is a common prolactin-releasing factor that regulates the synthesis and secretion of prolactin. In recent studies, microRNAs (miRNAs) have been found to play a key role in the regulation of pituitary hormones. However, there is a lack of systematic studies on the regulatory role that TRH plays on the pituitary transcriptome, and the role of miRNAs in the regulation of PRL synthesis and secretion by TRH lacks experimental evidence. In this study, we first investigated the changes in PRL synthesis and secretion in the rat pituitary gland after TRH administration. The results of transcriptomic analysis after TRH treatment showed that 102 genes, including those that encode Nppc, Fgf1, PRL, Cd63, Npw, and Il23a, were upregulated, and 488 genes, including those that encode Lats1, Cacna2d1, Top2a, and Tfap2a, were downregulated. These genes are all involved in the regulation of prolactin expression. The gene expression of miR-126a-5p, which regulates the level of PRL in the pituitary gland, was screened by analysis prediction software and by a dual luciferase reporter system. The data presented in this study demonstrate that TRH can regulate prolactin synthesis and secretion through miR-126a-5p, thereby improving our understanding of the molecular mechanism of TRH-mediated PRL secretion and providing a theoretical basis for the role of miRNAs in regulating the secretion of pituitary hormones.
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Voellger B, Zhang Z, Benzel J, Wang J, Lei T, Nimsky C, Bartsch JW. Targeting Aggressive Pituitary Adenomas at the Molecular Level-A Review. J Clin Med 2021; 11:jcm11010124. [PMID: 35011868 PMCID: PMC8745122 DOI: 10.3390/jcm11010124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/11/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022] Open
Abstract
Pituitary adenomas (PAs) are mostly benign endocrine tumors that can be treated by resection or medication. However, up to 10% of PAs show an aggressive behavior with invasion of adjacent tissue, rapid proliferation, or recurrence. Here, we provide an overview of target structures in aggressive PAs and summarize current clinical trials including, but not limited to, PAs. Mainly, drug targets in PAs are based on general features of tumor cells such as immune checkpoints, so that programmed cell death 1 (ligand 1) (PD-1/PD-L1) targeting may bear potential to cure aggressive PAs. In addition, epidermal growth factor receptor (EGFR), mammalian target of rapamycin (mTOR), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and their downstream pathways are triggered in PAs, thereby modulating tumor cell proliferation, migration and/or tumor angiogenesis. Temozolomide (TMZ) can be an effective treatment of aggressive PAs. Combination of TMZ with 5-Fluorouracil (5-FU) or with radiotherapy could strengthen the therapeutic effects as compared to TMZ alone. Dopamine agonists (DAs) are the first line treatment for prolactinomas. Dopamine receptors are also expressed in other subtypes of PAs which renders DAs potentially suitable to treat other subtypes of PAs. Furthermore, targeting the invasive behavior of PAs could improve therapy. In this regard, human matrix metalloproteinase (MMP) family members and estrogens receptors (ERs) are highly expressed in aggressive PAs, and numerous studies demonstrated the role of these proteins to modulate invasiveness of PAs. This leaves a number of treatment options for aggressive PAs as reviewed here.
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Affiliation(s)
- Benjamin Voellger
- Department of Neurosurgery, University Hospital Marburg, Baldingerstr., 35033 Marburg, Germany; (Z.Z.); (J.B.); (J.W.); (C.N.); (J.-W.B.)
- Correspondence: ; Tel.: +49-6421-58-66447
| | - Zhuo Zhang
- Department of Neurosurgery, University Hospital Marburg, Baldingerstr., 35033 Marburg, Germany; (Z.Z.); (J.B.); (J.W.); (C.N.); (J.-W.B.)
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China;
| | - Julia Benzel
- Department of Neurosurgery, University Hospital Marburg, Baldingerstr., 35033 Marburg, Germany; (Z.Z.); (J.B.); (J.W.); (C.N.); (J.-W.B.)
- Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Junwen Wang
- Department of Neurosurgery, University Hospital Marburg, Baldingerstr., 35033 Marburg, Germany; (Z.Z.); (J.B.); (J.W.); (C.N.); (J.-W.B.)
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China;
| | - Ting Lei
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China;
| | - Christopher Nimsky
- Department of Neurosurgery, University Hospital Marburg, Baldingerstr., 35033 Marburg, Germany; (Z.Z.); (J.B.); (J.W.); (C.N.); (J.-W.B.)
| | - Jörg-Walter Bartsch
- Department of Neurosurgery, University Hospital Marburg, Baldingerstr., 35033 Marburg, Germany; (Z.Z.); (J.B.); (J.W.); (C.N.); (J.-W.B.)
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Cooper O, Bonert VS, Rudnick J, Pressman BD, Lo J, Salvatori R, Yuen KCJ, Fleseriu M, Melmed S. EGFR/ErbB2-Targeting Lapatinib Therapy for Aggressive Prolactinomas. J Clin Endocrinol Metab 2021; 106:e917-e925. [PMID: 33150390 PMCID: PMC7823257 DOI: 10.1210/clinem/dgaa805] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Indexed: 02/07/2023]
Abstract
CONTEXT Approximately 10% to 20% of prolactinomas are resistant to dopamine agonist therapy. The ErbB signaling pathway may drive aggressive prolactinoma behavior. OBJECTIVE We evaluated lapatinib, an ErbB1-epidermal growth factor receptor (EGFR)/ErbB2 or human EGFR2 (HER2) tyrosine kinase inhibitor (TKI), in aggressive prolactinomas. DESIGN A prospective, phase 2a multicenter trial was conducted. SETTING This study took place at a tertiary referral pituitary center. PATIENTS Study participants included adults with aggressive prolactinomas showing continued tumor growth despite maximally tolerated dopamine agonist therapy. INTERVENTION Intervention included oral lapatinib 1250 mg/day for 6 months. MAIN OUTCOME MEASURES The primary end point was 40% reduction in any tumor dimension assessed by magnetic resonance imaging at study end; tumor response was assessed by Response Evaluation Criteria in Solid Tumors criteria. Secondary end points included prolactin (PRL) reduction, correlation of response with EGFR/HER2 expression, and safety. RESULTS Owing to rigorous inclusion criteria, of 24 planned participants, only 7 consented and 4 were treated. None achieved the primary end point but 3 showed stable disease, including 2 with a 6% increase and 1 with a 16.8% decrease in tumor diameter. PRL response was not always concordant with tumor response, as 2 showed 28% and 59% increases in PRL. The fourth participant had a PRL-secreting carcinoma and withdrew after 3 months of lapatinib because of imaging and PRL progression. EGFR/HER2 expression did not correlate with treatment response. Lapatinib was well tolerated overall, with reversible grade 1 transaminitis in 2 patients, grade 2 rash in 2 patients, and grade 1 asymptomatic bradycardia in 2 patients. CONCLUSIONS An oral TKI such as lapatinib may be an effective option for a difficult-to-treat patient with an aggressive prolactinoma.
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Affiliation(s)
- Odelia Cooper
- Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
- Correspondence and Reprint Requests: Odelia Cooper, MD, Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, 127 S San Vicente Blvd, A6600, Los Angeles, CA 90048, USA. E-mail:
| | - Vivien S Bonert
- Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Jeremy Rudnick
- Departments of Medicine, Neurology, and Neurosurgery, Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Barry D Pressman
- Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California
| | - Janet Lo
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, Massachusetts
| | - Roberto Salvatori
- Division of Endocrinology, Diabetes, and Metabolism and Pituitary Center, Johns Hopkins Hospital, Baltimore, Maryland
| | - Kevin C J Yuen
- Department of Neuroendocrinology and Neurosurgery, Barrow Pituitary Center, Barrow Neurological Institute, University of Arizona College of Medicine and Creighton School of Medicine, Phoenix, Arizona
| | - Maria Fleseriu
- Pituitary Center, Departments of Medicine (Endocrinology) and Neurological Surgery, Oregon Health & Science University, Portland, Oregon
| | - Shlomo Melmed
- Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
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Pituitary Actions of EGF on Gonadotropins, Growth Hormone, Prolactin and Somatolactins in Grass Carp. BIOLOGY 2020; 9:biology9090279. [PMID: 32911654 PMCID: PMC7564354 DOI: 10.3390/biology9090279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/27/2020] [Accepted: 09/05/2020] [Indexed: 01/08/2023]
Abstract
Simple Summary In mammals, the functions of epidermal growth factor (EGF) have been widely studied. However, little is known about the pituitary actions of EGF in teleost. Using primary cultured grass carp pituitary cells as model, we found that EGF could reduce pituitary luteinizing hormone β (LHβ) mRNA expression, but induce pituitary growth hormone (GH), prolactin (PRL) and somatolactins (SL) mRNA expression. Furthermore, we also found that NKB could suppress EGF-induced PRL mRNA expression in grass carp pituitary cells. These results suggested that EGF could directly regulate pituitary hormones expression in teleost. Abstract In mammals, epidermal growth factor (EGF) plays a vital role in both pituitary physiology and pathology. However, the functional role of EGF in the regulation of pituitary hormones has rarely reported in teleost. In our study, using primary cultured grass carp pituitary cells as an in vitro model, we examined the effects of EGF on pituitary hormone secretion and gene expression as well as the post-receptor signaling mechanisms involved. Firstly, we found that EGF significantly reduced luteinizing hormone (LHβ) mRNA expression via ErbB1 coupled to ERK1/2 pathway, but had no effect on LH release in grass carp pituitary cells. Secondly, the results showed that EGF was effective in up-regulating mRNA expression of growth hormone (GH), somatolactin α (SLα) and somatolactin β (SLβ) via ErbB1 and ErbB2 and subsequently coupled to MEK1/2/ERK1/2 and PI3K/Akt/mTOR pathways, respectively. However, EGF was not effective in GH release in pituitary cells. Thirdly, we found that EGF strongly induced pituitary prolactin (PRL) release and mRNA expression, which was mediated by ErbB1 and subsequent stimulation of MEK1/2/ERK1/2 and PI3K/Akt/mTOR pathways. Interestingly, subsequent study further found that neurokinin B (NKB) significantly suppressed EGF-induced PRL mRNA expression, which was mediated by neurokinin receptor (NK2R) and coupled to AC/cAMP/PKA signal pathway. These results suggested that EGF could differently regulate the pituitary hormones expression in grass carp pituitary cells.
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Milk somatic cell derived transcriptome analysis identifies regulatory genes and pathways during lactation in Indian Sahiwal cattle (Bos indicus). Mol Biol Rep 2020; 47:7029-7038. [PMID: 32880836 DOI: 10.1007/s11033-020-05764-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/28/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND The present study is an effort to understand the genomic drivers of lactation in Sahiwal (Bos indicus), the best milch cattle breed of the tropics. METHODS RNA sequencing of four animals from early, mid and late lactation stages was performed using milk somatic cells as source of RNA. RESULTS The genes encoding the milk casein and whey proteins showed highest expression in early and mid lactation, with a declining trend towards the late stage. The enhanced expression of PLIN2, FABP5 and FABP3 genes in mid lactation suggests enrichment of the PPARα pathway which is linked to fatty acid metabolism. A gradual decline in the percentage of genes involved in metabolism of proteins, mRNA and insulin synthesis from early to late lactation reflected transition from lactogenesis to involution. Major biological pathways maintained throughout lactation were adaptive immune system, FGF signaling, EGFR signaling, activated TLR4 signaling, NFkB and MAP kinases activation mediated by TLR4 signaling repertoire. Differential expression analysis revealed 547, 1010 and 1313 differentially expressed genes (p < 0.05) between early-late, early-mid and mid-late stages, respectively. The topmost regulatory genes identified by network analysis from the differentially expressed genes, were involved in Chemokine receptor, GPCR and EGFR1 pathways. CONCLUSION The genes and pathways delineated in this study have regulatory implications in cell morphogenesis, lipid droplet formation and protein synthesis in the course of lactation. The study provides an insight into the expression profile of genes influencing milk properties and lactation in Sahiwal cattle.
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Duran P, Sandoval A, González-Ramírez R, Zarco N, Felix R. Regulation of the Ca 2+ channel α 2δ-1 subunit expression by epidermal growth factor via the ERK/ELK-1 signaling pathway. Am J Physiol Endocrinol Metab 2020; 319:E232-E244. [PMID: 32369417 DOI: 10.1152/ajpendo.00007.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Voltage-gated Ca2+ (CaV) channels are expressed in endocrine cells where they contribute to hormone secretion. Diverse chemical messengers, including epidermal growth factor (EGF), are known to affect the expression of CaV channels. Previous studies have shown that EGF increases Ca2+ currents in GH3 pituitary cells by increasing the number of high voltage-activated (HVA) CaV channels at the cell membrane, which results in enhanced prolactin (PRL) secretion. However, little is known regarding the mechanisms underlying this regulation. Here, we show that EGF actually increases the expression of the CaVα2δ-1 subunit, a key molecular component of HVA channels. The analysis of the gene promoter encoding CaVα2δ-1 (CACNA2D1) revealed binding sites for transcription factors activated by the Ras/Raf/MEK/ERK signaling cascade. Chromatin immunoprecipitation and site-directed mutagenesis showed that ELK-1 is crucial for the transcriptional regulation of CACNA2D1 in response to EGF. Furthermore, we found that EGF increases the membrane expression of CaVα2δ-1 and that ELK-1 overexpression increases HVA current density, whereas ELK-1 knockdown decreases the functional expression of the channels. Hormone release assays revealed that CaVα2δ-1 overexpression increases PRL secretion. These results suggest a mechanism for how EGF, by activating the Ras/Raf/MEK/ERK/ELK-1 pathway, may influence the expression of HVA channels and the secretory behavior of pituitary cells.
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Affiliation(s)
- Paz Duran
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), Mexico City, Mexico
| | - Alejandro Sandoval
- School of Medicine FES Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico
| | - Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | | | - Ricardo Felix
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), Mexico City, Mexico
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Nogami H, Koshida R, Omori H, Shibata M, Harigaya T, Takei Y. Inhibition of epidermal growth factor receptor stimulates prolactin expression in primary culture of the mouse pituitary gland. J Neuroendocrinol 2019; 31:e12764. [PMID: 31251840 DOI: 10.1111/jne.12764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 06/23/2019] [Accepted: 06/25/2019] [Indexed: 11/30/2022]
Abstract
The roles of epidermal growth factor (EGF) in the regulation of prolactin (PRL) gene expression in the normal pituitary gland remain poorly understood. In the present study, the effects of EGF and an inhibitor of the EGF receptor, erlotinib, on PRL gene expression were examined both in the pituitary tumour cell line GH3 and in a primary culture of the mouse pituitary gland under similar experimental conditions. The results showed that EGF stimulated PRL expression in GH3 cells, but not in normal cells. Erlotinib was found to counteract EGF in GH3 cells inhibiting the PRL expression enhanced by EGF. By contrast, erlotinib induced an elevation in the PRL mRNA levels in the primary culture of the adult pituitary gland and the initiation of PRL production in the culture of the foetal pituitary gland in which PRL production had not yet occurred. Western blot analyses showed that EGF induced and erlotinib inhibited the activation of extracellular regulated protein kinase equally in GH3 and normal cells. These results suggest that the consequences of EGF receptor activation in normal PRL cells contradict those in adenomatous PRL cells.
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Affiliation(s)
- Haruo Nogami
- Department of Physical Therapy, School of Health Sciences, Japan University of Health Sciences, Satte, Japan
| | - Ryusuke Koshida
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Hiroyuki Omori
- Department of Physical Therapy, School of Health Sciences, Japan University of Health Sciences, Satte, Japan
| | - Masahiro Shibata
- Department of Physical Therapy, School of Health Sciences, Japan University of Health Sciences, Satte, Japan
| | - Toshio Harigaya
- Laboratory of Functional Anatomy, Department of Life Sciences, Faculty of Agriculture, Meiji University, Kawasaki, Japan
| | - Yosuke Takei
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
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Camilletti MA, Abeledo-Machado A, Ferraris J, Pérez PA, Faraoni EY, Pisera D, Gutierrez S, Díaz-Torga G. Role of GPER in the anterior pituitary gland focusing on lactotroph function. J Endocrinol 2019; 240:99-110. [PMID: 30400046 DOI: 10.1530/joe-18-0402] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 10/19/2018] [Indexed: 12/22/2022]
Abstract
Ovarian steroids control a variety of physiological functions. They exert actions through classical nuclear steroid receptors, but rapid non-genomic actions through specific membrane steroid receptors have been also described. In this study, we demonstrate that the G-protein-coupled estrogen receptor (GPER) is expressed in the rat pituitary gland and, at a high level, in the lactotroph population. Our results revealed that ~40% of the anterior pituitary cells are GPER positive and ~35% of the lactotrophs are GPER positive. By immunocytochemical and immuno-electron-microscopy studies, we demonstrated that GPER is localized in the plasmatic membrane but is also associated to the endoplasmic reticulum in rat lactotrophs. Moreover, we found that local Gper expression is regulated negatively by 17β-estradiol (E2) and progesterone (P4) and fluctuates during the estrus cycle, being minimal in proestrus. Interestingly, lack of ovarian steroids after an ovariectomy (OVX) significantly increased pituitary GPER expression specifically in the three morphologically different subtypes of lactotrophs. We found a rapid estradiol stimulatory effect on PRL secretion mediated by GPER, both in vitro and ex vivo, using a GPER agonist G1, and this effect was prevented by the GPER antagonist G36, demonstrating a novel role for this receptor. Then, the increased pituitary GPER expression after OVX could lead to alterations in the pituitary function as all three lactotroph subtypes are target of GPER ligand and could be involved in the PRL secretion mediated by GPER. Therefore, it should be taken into consideration in the response of the gland to an eventual hormone replacement therapy.
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Affiliation(s)
- María Andrea Camilletti
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Alejandra Abeledo-Machado
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Jimena Ferraris
- Instituto de Investigaciones Biomédicas, Facultad de Medicina, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Pablo A Pérez
- Centro de Microscopia Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Medicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Erika Y Faraoni
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Daniel Pisera
- Instituto de Investigaciones Biomédicas, Facultad de Medicina, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Silvina Gutierrez
- Centro de Microscopia Electrónica, Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Facultad de Ciencias Medicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Graciela Díaz-Torga
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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Qin X, Ye C, Zhou X, Jia J, Xu S, Hu Q, Hu G. NK3R Mediates the EGF-Induced SLα Secretion and mRNA Expression in Grass Carp Pituitary. Int J Mol Sci 2018; 20:ijms20010091. [PMID: 30587833 PMCID: PMC6337684 DOI: 10.3390/ijms20010091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 12/15/2018] [Indexed: 12/23/2022] Open
Abstract
Epidermal growth factor (EGF) is a potent regulator of cell function in many cell types. In mammals, the EGF/EGFR system played an important role in both pituitary physiology and pathology. However, it is not clear about the pituitary action of EGF in lower vertebrates. In this study, using grass carp as a model, we found that EGF could stimulate NK3R mRNA and protein expression through pituitary ErbB1 and ErbB2 coupled to MEK/ERK and PI3K/Akt/mTOR pathways. In addition, EGF could also induce pituitary somatolactin α (SLα) secretion and mRNA expression in a dose- and time-dependent manner in vivo and in vitro. The stimulatory actions of EGF on SLα mRNA expression were also mediated by PI3K/Akt/mTOR and MEK/ERK pathways coupled to ErbB1 and ErbB2 activation. Our previous study has reported that neurokinin B (NKB) could also induce SLα secretion and mRNA expression in carp pituitary cells. In the present study, interestingly, we found that EGF could significantly enhance NKB-induced SLα mRNA expression. Further studies found that NK3R antagonist SB222200 could block EGF-induced SLα mRNA expression, indicating an NK3R requirement. Furthermore, cAMP/PKA inhibitors and PLC/PKC inhibitors could both abolish EGF- and EGF+NKB-induced SLα mRNA expression, which further supported that EGF-induced SLα mRNA expression is NK3R dependent.
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Affiliation(s)
- Xiangfeng Qin
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Cheng Ye
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Xiaoyun Zhou
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jingyi Jia
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Shaohua Xu
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Qiongyao Hu
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Guangfu Hu
- College of Fisheries, Hubei Province Engineering Laboratory for Pond Aquaculture, Huazhong Agricultural University, Wuhan 430070, China.
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Chen KHE, Bustamante K, Nguyen V, Walker AM. Involvement of miR-106b in tumorigenic actions of both prolactin and estradiol. Oncotarget 2018; 8:36368-36382. [PMID: 28422740 PMCID: PMC5482661 DOI: 10.18632/oncotarget.16755] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 03/21/2017] [Indexed: 02/07/2023] Open
Abstract
Prolactin promotes a variety of cancers by an array of different mechanisms. Here, we have investigated prolactin's inhibitory effect on expression of the cell cycle-regulating protein, p21. Using a miRNA array, we identified a number of miRNAs upregulated by prolactin treatment, but one in particular that was strongly induced by prolactin and predicted to bind to the 3′UTR of p21 mRNA, miR-106b. By creating a p21 mRNA 3′UTR-luciferase mRNA construct, we demonstrated degradation of the construct in response to prolactin in human breast, prostate and ovarian cancer cell lines. Increased expression of miR-106b replicated, and anti-miR-106b counteracted, the effects of prolactin on degradation of the 3′UTR construct, p21 mRNA levels, and cell proliferation in breast (T47D) and prostate (PC3) cancer cells. Increased expression of miR-106b also stimulated migration of the very epithelioid T47D cell line. By contrast, anti-miR-106b dramatically decreased expression of the mesenchymal markers, SNAIL-2, TWIST-2, VIMENTIN, and FIBRONECTIN. Using signaling pathway inhibitors and the 3′UTR construct, induction of miR-106b by prolactin was determined to be mediated through the MAPK/ERK and PI3K/Akt pathways and not through Jak2/Stat5 in both T47D and PC3 cells. Prolactin activation of MAPK/ERK and PI3K/Akt also activates ERα in the absence of an ERα ligand. 17β-estradiol promoted degradation of the construct in both cell lines and pre-incubation in the estrogen antagonist, Fulvestrant, blocked the ability of both prolactin and 17β-estradiol to induce the construct-degrading activity. Together, these data support a convergence of the prolactin and 17β-estradiol miR-106b-elevating signaling pathways at ERα.
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Affiliation(s)
- Kuan-Hui Ethan Chen
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
| | - Karissa Bustamante
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
| | - Vi Nguyen
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
| | - Ameae M Walker
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
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Ristic N, Ajdzanovic V, Manojlovic-Stojanoski M, Maliković J, Uscebrka G, Markovic Z, Milosevic V. Effects of Estradiol on Histological Parameters and Secretory Ability of Pituitary Mammotrophs in Ovariectomized Female Rats. CELL JOURNAL 2017; 19:461-468. [PMID: 28836408 PMCID: PMC5570411 DOI: 10.22074/cellj.2017.4334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/16/2016] [Indexed: 01/02/2023]
Abstract
Objective Estrogen replacement therapy remains current as a therapeutic approach to
treat menopausal symptoms and may significantly affect hormone-producing cells in the
female pituitaries. The aim of this study was to examine the histological parameters of
pituitary mammotrophs and prolactin secretion after chronic estradiol treatment in ovariectomized adult female rats, reflecting premature menopause. Materials and Methods In this experimental study, adult female Wistar rats were divided into non-ovariectomized (C),
ovariectomized (OVX) and estradiol-treated ovariectomized (OVX+E) groups. Estradiol dipropionate [0.625 mg/kg body mass per
day] was administered for four weeks, while the C and OVX groups received vehicle
alone. Mammotrophs were identified by the peroxidase-antiperoxidase (PAP) immunohistochemical procedure, while prolactin concentrations were measured by the
non-isotopic two-step assay (Delfia) method. Comparison of the differences between
groups was performed using one-way analysis of variance (ANOVA) and Tukay (honest significant difference) HSD test.
Results Ovariectomy caused significant (P<0.05) decreases in mammotroph optical
density (OD), volume density (VV) and number per mm2 by 29, 27 and 34%, respectively, in comparison with the C females. In the OVX+E group, significant (P<0.05)
increases in OD, cell volume, VVand number of mammotrophs per mm2 by 181, 15%,
5.8-fold and 5.2-fold, respectively, were observed when compared to OVX animals.
The serum prolactin concentration in OVX females was significantly (P<0.05) decreased by 14% in comparison to the C group, while in OVX+E females, prolactin
levels were significantly (P<0.05) increased by 53% compared to the OVX controls. Conclusion Estradiol supplementation in ovariectomized females is followed by
stimulatory histological and secretory changes of the mammotrophs. These results
could serve as indicators of possible prolactinome development upon estradiol application in premature menopausal subjects.
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Affiliation(s)
- Natasa Ristic
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
| | - Vladimir Ajdzanovic
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
| | - Milica Manojlovic-Stojanoski
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Jovana Maliković
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
| | - Gordana Uscebrka
- Department of Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Novi Sad, Serbia
| | | | - Verica Milosevic
- Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia
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Wolff RB, Gomes RCT, do Amaral VC, da Silva PL, Simoncini T, Prosdocimi FC, Simoes RS, Simões MJS, Baracat EC, Soares JM. Effects of hyperprolactinemia on the tibial epiphyseal plate of mice treated with sex hormones. Gynecol Endocrinol 2016; 32:30-3. [PMID: 26193892 DOI: 10.3109/09513590.2015.1068753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to evaluate the effects of metoclopramide-induced hyperprolactinemia on the tibial epiphyseal plate of hormone-treated oophorectomized mice. For this purpose, 18 animals with intact ovaries were allocated to two groups, M (metoclopramide) and V (vehicle). One hundred and eight oophorectomized animals were allocated to 12 subgroups: Oophx/V (vehicle); Ooph/M (metoclopramide); Oophx/V + E (vehicle + estradiol); Oophx/M + E (metoclopramide + estradiol); Oophx/V + P (vehicle + progesterone); Oophx/M + P (metoclopramide + progesterone); Oophx/V + T (vehicle + testosterone); Oophx/M + T (metoclopramide + testosterone); Oophx/V + E + P (Vehicle + estradiol + progesterone); Oophx/M + E + P (metoclopramide + estradiol + progesterone); Oophx/V + E + P + T (vehicle + estradiol + progesterone + testosterone); Oophx/M + E + P + T (metoclopramide + estradiol + progesterone + testosterone). After a 50-day treatment was performed histomorphometric and immunohistochemical cell death analysis. In the epiphyseal plate of the hyperprolactinemic and/or oophorectomized animals, cell proliferation and bone formation decreased, inducing intensified cell death. In the sex steroid-treated animals, estrogen boosted cell proliferation; progesterone, bone formation and testosterone, both cell proliferation and bone formation. These findings suggest that oophorectomy and hyperprolactinemia changed epiphyseal plate morphology causing cartilage degeneration. Treatment with combined sex steroids may diminish such deleterious effects.
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Affiliation(s)
- Roberta B Wolff
- a Departamento de Morfologia e Genética , Disciplina de Histologia e Biologia Estrutural, Universidade Federal de São Paulo - UNIFESP , São Paulo (SP) , Brazil
| | - Regina Celia T Gomes
- a Departamento de Morfologia e Genética , Disciplina de Histologia e Biologia Estrutural, Universidade Federal de São Paulo - UNIFESP , São Paulo (SP) , Brazil
| | - Vinicius C do Amaral
- b Departamento de Obstetrícia e Ginecologia , Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo - USP , São Paulo (SP) , Brazil
- c Division of Obstetrics and Gynecology, Department of Clinical and Experimental Medicine , University of Pisa , Pisa (PI) , Italy , and
- d Instituto de Ciencias da Saude da Universidade Paulista, UNIP , Sao Paulo (SP) , Brazil
| | - Priscilla L da Silva
- b Departamento de Obstetrícia e Ginecologia , Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo - USP , São Paulo (SP) , Brazil
| | - Tommaso Simoncini
- c Division of Obstetrics and Gynecology, Department of Clinical and Experimental Medicine , University of Pisa , Pisa (PI) , Italy , and
| | - Fabio Cesar Prosdocimi
- d Instituto de Ciencias da Saude da Universidade Paulista, UNIP , Sao Paulo (SP) , Brazil
| | - Ricardo S Simoes
- b Departamento de Obstetrícia e Ginecologia , Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo - USP , São Paulo (SP) , Brazil
| | - Manuel Jesus S Simões
- a Departamento de Morfologia e Genética , Disciplina de Histologia e Biologia Estrutural, Universidade Federal de São Paulo - UNIFESP , São Paulo (SP) , Brazil
| | - Edmund C Baracat
- b Departamento de Obstetrícia e Ginecologia , Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo - USP , São Paulo (SP) , Brazil
| | - José Maria Soares
- b Departamento de Obstetrícia e Ginecologia , Hospital das Clínicas da Faculdade de Medicina, Universidade de São Paulo - USP , São Paulo (SP) , Brazil
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Salgado R, Pereiro N, López-Doval S, Lafuente A. Initial study on the possible mechanisms involved in the effects of high doses of perfluorooctane sulfonate (PFOS) on prolactin secretion. Food Chem Toxicol 2015; 83:10-6. [DOI: 10.1016/j.fct.2015.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 05/18/2015] [Accepted: 05/21/2015] [Indexed: 01/09/2023]
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Voicu V, Medvedovici A, Ranetti AE, Rădulescu FŞ. Drug-induced hypo- and hyperprolactinemia: mechanisms, clinical and therapeutic consequences. Expert Opin Drug Metab Toxicol 2013; 9:955-68. [PMID: 23600946 DOI: 10.1517/17425255.2013.791283] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION The altered profiles of prolactin secretion in the anterior hypophysis, generated by pathological, pharmacological or toxicological causes, have special consequences on multiple functions in both genders. AREAS COVERED This selective review presents the main mechanisms controlling prolactin secretion, focusing on the interplay of various neurotransmitters or xenobiotics, but also on the role of psychic or posttraumatic stress. A detailed analysis of several pharmacotherapeutic groups with hyperprolactinemic effects emphasize on the relevance of the pharmacokinetic/pharmacodynamic mechanisms and the clinical significance of the long term administration. EXPERT OPINION Accurate monitoring and evaluation of the hyperprolactinemia induced by xenobiotics is strongly recommended. The typical antipsychotics and some of the atypical agents (amisulpride, risperidone, paliperidone), as well as some antidepressants, antihypertensives and prokinetics, are the most important groups inducing hyperprolactinemia. The hyperprolactinemic effects are correlated with their affinity for dopamine D2 receptors, their blood-brain barrier penetration and, implicitly, the requested dose for adequate occupancy of cerebral D2 receptors. Consequently, integration of available pharmacokinetic and pharmacodynamic data supports the idea of therapeutic switch to non-hyperprolactinemic agents (especially aripiprazole) or their association, for an optimal management of antipsychotic-induced hyperprolactinemia. Possible alternative strategies for counteracting the xenobiotics-induced hyperprolactinemia are also mentioned.
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Affiliation(s)
- Victor Voicu
- University of Medicine and Pharmacy Carol Davila, Faculty of Medicine, Department of Clinical Pharmacology, Toxicology and Psychopharmacology, Bucharest 011643, Romania.
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16
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Coombes RC, Tat T, Miller ML, Reise JA, Mansi JL, Hadjiminas DJ, Shousha S, Elsheikh SE, Lam EWF, Horimoto Y, El-Bahrawy M, Aboagye EO, Contractor KB, Shaw JA, Walker RA, Marconell MH, Palmieri C, Stebbing J. An open-label study of lapatinib in women with HER-2-negative early breast cancer: the lapatinib pre-surgical study (LPS study). Ann Oncol 2013; 24:924-30. [PMID: 23233650 DOI: 10.1093/annonc/mds594] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND This phase II, open-label, multicentre study aimed to evaluate changes in cell proliferation and biomarkers, as well as efficacy of lapatinib in treatment-naïve patients with HER-2-negative primary breast cancer. PATIENTS AND METHODS Patients received 1500 mg lapatinib for 28-42 days before surgery with repeat biopsies and measurements. The primary end point was inhibition of cell proliferation measured by Ki67; the secondary end points included clinical response, adverse events and changes in FOXO3a, FOXM1, p-AKT and HER-3. RESULTS Overall, there was no significant reduction in Ki67 with treatment (assessment carried out in 28 of 31 subjects enrolled). However, four patients (14%) showed a reduction in Ki67 ≥50%. Four of 25 patients (16%) had a partial response to treatment judged by sequential ultrasound measurements. Response, in terms of either Ki67 or ultrasound, did not relate to changes in any biomarker assessed at baseline, including the estrogen receptor (ER) and epidermal growth factor receptor (EGFR). However, all four clinical responders were HER-3 positive, as were three of four Ki67 responders. CONCLUSIONS Overall, a pre-surgical course of lapatinib monotherapy had little effect on this group of patients; however, in subsets of patients, especially those with HER-3-positive tumors, we observed either reduction in proliferation (Ki67) or tumor size; EGFR/ER status had no impact.
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Affiliation(s)
- R C Coombes
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, 1st Floor ICTEM, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
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17
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Damiano JS, Rendahl KG, Karim C, Embry MG, Ghoddusi M, Holash J, Fanidi A, Abrams TJ, Abraham JA. Neutralization of Prolactin Receptor Function by Monoclonal Antibody LFA102, a Novel Potential Therapeutic for the Treatment of Breast Cancer. Mol Cancer Ther 2012; 12:295-305. [DOI: 10.1158/1535-7163.mct-12-0886] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Tong Y, Zheng Y, Zhou J, Oyesiku NM, Koeffler HP, Melmed S. Genomic characterization of human and rat prolactinomas. Endocrinology 2012; 153:3679-91. [PMID: 22635680 PMCID: PMC3404356 DOI: 10.1210/en.2012-1056] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although prolactinomas can be effectively treated with dopamine agonists, about 20% of patients develop dopamine resistance or tumor recurrence after surgery, indicating a need for better understanding of underlying disease mechanisms. Although estrogen-induced rat prolactinomas have been widely used to investigate the development of this tumor, the extent that the model recapitulates features of human prolactinomas is unclear. To prioritize candidate genes and gene sets regulating human and rat prolactinomas, microarray results derived from human prolactinomas and pituitaries of estrogen-treated ACI rats were integrated and analyzed. A total of 4545 differentially expressed pituitary genes were identified in estrogen-treated ACI rats [false discovery rate (FDR) < 0.01]. By comparing pituitary microarray results derived from estrogen-treated Brown Norway rats (a strain not sensitive to estrogen), 4073 genes were shown specific to estrogen-treated ACI rats. Human prolactinomas exhibited 1177 differentially expressed genes (FDR < 0.05). Combining microarray data derived from human prolactinoma and pituitaries of estrogen-treated ACI rat, 145 concordantly expressed genes, including E2F1, Myc, Igf1, and CEBPD, were identified. Gene set enrichment analysis revealed that 278 curated pathways and 59 gene sets of transcription factors were enriched (FDR < 25%) in estrogen-treated ACI rats, suggesting a critical role for Myc, E2F1, CEBPD, and Sp1 in this rat prolactinoma. Similarly increased Myc, E2F1, and Sp1 expression was validated using real-time PCR and Western blot in estrogen-treated Fischer rat pituitary glands. In summary, characterization of individual genes and gene sets in human and in estrogen-induced rat prolactinomas validates the model and provides insights into genomic changes associated with this commonly encountered pituitary tumor.
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Affiliation(s)
- Yunguang Tong
- Department of Medicine, Cedars-Sinai Medical Center, Academic Affairs, Room 2015, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
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Nogami H, Soya H, Hiraoka Y, Aiso S, Hisano S. Epidermal growth factor-activated extracellular signal-regulated kinase suppresses growth hormone expression and stimulates proliferation in MtT/ E cells. J Neuroendocrinol 2012; 24:357-65. [PMID: 22026435 DOI: 10.1111/j.1365-2826.2011.02247.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The mechanism for the inhibition of growth hormone (GH) expression by the epidermal growth factor (EGF) was examined in two clonal cell lines, MtT/E and MtT/S. The former has a negligible basal level of GH, whereas the latter has a high basal GH. The treatment of MtT/E cells with retinoic acid resulted in a significant increase in GH mRNA and subsequently GH. This stimulatory response to retinoic acid was strongly suppressed by EGF. This suppression was associated with an increase in the phosphorylation of extracellular signal-regulated kinase 1 and 2 (Erk1/2). The MEK [mitogen-activated protein kinase (MAPK) kinases that activate ERK1 and ERK2] inhibitor, PD98059, clearly inhibited the phosphorylation of Erk1/2 and restored the stimulatory effects of retinoic acid. These results suggest that the inhibitory effects of EGF on GH expression are mediated by MAPK activation in these cells. By contrast to the GH-producing clones examined previously, EGF showed a marked stimulation of proliferation of the MtT/E cells through a mechanism dependent on MAPK activation. On the other hand, the inhibitory effect of EGF on GH expression was less pronounced and the stimulation of cellular proliferation was not seen in MtT/S cells, even though it induced Erk-phosphorylation similar to that seen in MtT/E. The distinct difference in the response to EGF between these two GH cell lines appears to be attributed to differences in the function of MAPK cascade in each cell line. This may reflect the developmental stage of the cells from which MtT/E and MtT/S are derived.
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Affiliation(s)
- H Nogami
- Laboratory of Neuroendocrinology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan.
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20
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Yang H, Nguyen TT, An BS, Choi KC, Jeung EB. Synergistic effects of parabens on the induction of calbindin-D9k gene expression act via a progesterone receptor-mediated pathway in GH3 cells. Hum Exp Toxicol 2011; 31:134-44. [DOI: 10.1177/0960327111422402] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Although the endocrine-disrupting bioactivity of parabens is weakly estrogenic (parabens are xenoestrogens), their combined synergistic effect is unknown. The aim of this study was to investigate the effects of methyl paraben (MP), ethyl paraben (EP), propyl paraben (PP), isopropyl paraben (IPP), butyl paraben (BP), and isobutyl paraben (IBP), either alone or in combination (MP + EP + PP + BP; PP + IPP; and BP + IBP) on the induction of the estrogenic biomarker gene, calbindin-D9k( CaBP-9k), in rat pituitary lactosomatotrophic GH3 cells. The expression of CaBP-9k mRNA and protein was analyzed using real-time PCR and Western blot analysis, respectively. After 24 h of treatment, a significant increase in CaBP-9k expression was observed. This was dependent upon the length of the paraben alkyl chains (shortest in MP and longest in IBP). Interestingly, the synergistic effects of these paraben combinations were observed at a dose (10−5 M) of these parabens, which induced the highest expression of CaBP-9k mRNA and protein. To investigate the involvement of estrogen receptors (ERs) and progesterone receptors (PRs), through which parabens exert their effects, the expression levels of ERα and PR-B were also examined. The expression of ERα mRNA and protein fluctuated after paraben treatment in GH3 cells, which was not significant. However, the expression level of ERα gene was induced when cotreated with 17β-estradiol (E2) and ICI 182, 780 (estrogen receptor antagonist). The different combinations of parabens induced the expression of the PR-B gene, which was abolished by cotreatment with ICI 182,780. The expression patterns of CaBP-9k and PR-B genes appeared to be similar in response to paraben treatments. This implied that CaBP-9k expression in GH3 cells may be induced by parabens via a PR-mediated pathway. Taken together, these results suggest that exposure to multiple parabens at low concentrations may increase their synergistic estrogenic activities in GH3 cells through a PR-mediated pathway.
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Affiliation(s)
- H Yang
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - T-T Nguyen
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - B-S An
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - K-C Choi
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - E-B Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
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Cooper O, Vlotides G, Fukuoka H, Greene MI, Melmed S. Expression and function of ErbB receptors and ligands in the pituitary. Endocr Relat Cancer 2011; 18:R197-211. [PMID: 21917845 PMCID: PMC3758362 DOI: 10.1530/erc-11-0066] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The role of ErbB family in discreet pituitary functions is reviewed. Several ErbB receptor ligands, EGF, TGFα, and heregulin are differentially expressed in normal gonadotroph and lacto-somatotroph lineages, and other elements of the anterior pituitary. ErbB receptors, i.e. EGFR and ErbB2, are also localized to the anterior pituitary with preferential EGFR lactosomatotroph expression. EGF regulates CRH and ACTH secretion and corticotroph proliferation as well as exhibiting autocrine and paracrine effects on gonadotrophs and on lactosomatotroph proliferation, gene and protein expression, and hormonal secretion. EGF and EGFR are expressed in both functioning and non-functioning pituitary adenomas, with higher expression in more aggressive tumor subtypes. ErbB2 receptor is detected in all tumor subtypes, particularly in invasive tumors. ErbB tyrosine kinase inhibitors regulate hormonal secretion, cell morphology, and proliferation in lacto-somatotroph tumors, reflecting the emerging application of targeted pituitary therapeutics.
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Affiliation(s)
- Odelia Cooper
- Department of Medicine, Pituitary Center, Cedars-Sinai Medical Center, Academic Affairs, Room 2015, 8700 Beverly Boulevard, Los Angeles, California 90048, USA
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Dahlhoff M, Blutke A, Wanke R, Wolf E, Schneider MR. In vivo evidence for epidermal growth factor receptor (EGFR)-mediated release of prolactin from the pituitary gland. J Biol Chem 2011; 286:39297-306. [PMID: 21914800 DOI: 10.1074/jbc.m111.243493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Members of the epidermal growth factor receptor (EGFR/ERBB) system are essential local regulators of mammary gland development and function. Emerging evidence suggests that EGFR signaling may also influence mammary gland activity indirectly by promoting the release of prolactin from the pituitary gland in a MAPK and estrogen receptor-α (ERα)-dependent manner. Here, we report that overexpression of the EGFR ligand betacellulin (BTC) causes a lactating-like phenotype in the mammary gland of virgin female mice including the major hallmarks of lactogenesis. BTC transgenic (BTC-tg) females showed reduced levels of prolactin in the pituitary gland and increased levels of the hormone in the circulation. Furthermore, treatment of BTC-tg females with bromocriptine, an inhibitor of prolactin secretion, blocked the development of the lactation-like phenotype, suggesting that it is caused by central release of prolactin rather than by local actions of BTC in the mammary gland. Introduction of the antimorphic Egfr allele Wa5 also blocked the appearance of the mammary gland alterations, revealing that the phenotype is EGFR-dependent. We detected an increase in MAPK activity, but unchanged phosphorylation of ERα in the pituitary gland of BTC-tg females as compared with control mice. These results provide the first functional evidence in vivo for a role of the EGFR system in regulating mammary gland activity by modulating prolactin release from the pituitary gland.
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Affiliation(s)
- Maik Dahlhoff
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Munich 81377, Germany
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23
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Vo TTB, Jung EM, Choi KC, Yu FH, Jeung EB. Estrogen receptor α is involved in the induction of Calbindin-D(9k) and progesterone receptor by parabens in GH3 cells: a biomarker gene for screening xenoestrogens. Steroids 2011; 76:675-81. [PMID: 21473877 DOI: 10.1016/j.steroids.2011.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 12/12/2022]
Abstract
The effects of paraben, a xenoestrogen with known endocrine disrupting bioactivity were evaluated. We used the induction of an estrogenic biomarker gene - Calbindin-D(9k) (CaBP-9k) to investigate the xenoestrogenic activity of a panel of parabens (methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutylparabens) in GH3 rat pituitary cancer cell line. Following 24-h treatment, a significant increase in CaBP-9k expression of transcript and protein was dependent on the concentration-treated as well as the linear length of the alkyl chain from methyl- to isobutylparabens. Interestingly, co-treatment with fulvestrant, a pure antiestrogen largely reversed the paraben-dependent induction of CaBP-9k mRNA and protein in GH3 cell line. To better understand the mechanism of CaBP-9k induction by these endocrine disrupting compounds, we measured the levels of estrogen receptor (ERα) and progesterone receptor (PR) expression following parabens exposure. Also, we monitored the transiently transfected with plasmids containing of estrogen response element (ERE) sequence into GH3. In the GH3 cells, a large increase in PR mRNA and protein was observed in a concentration-dependent manner after parabens treatment that was effectively blocked in the presence of antagonist of 17β-estradiol (fulvestrant). And, luciferase activity was expressed from the putative ERE and expression was stimulated by parabens. To confirm that ERα signaling is involved in parabens induction of CaBP-9k and PR mRNA and protein, we treated GH3 cells with an antiestrogen, fulvestrant, which blocked the paraben-induced upregulation of CaBP-9k and PR. Taken together, these results indicate that CaBP-9k and PR is induced by parabens via the ER pathway in GH3 cell line.
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Affiliation(s)
- Thuy T B Vo
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea
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Gantus MAV, Alves LM, Stipursky J, Souza ECL, Teodoro AJ, Alves TR, Carvalho DP, Martinez AMB, Gomes FCA, Nasciutti LE. Estradiol modulates TGF-β1 expression and its signaling pathway in thyroid stromal cells. Mol Cell Endocrinol 2011; 337:71-9. [PMID: 21315800 DOI: 10.1016/j.mce.2011.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Revised: 01/31/2011] [Accepted: 02/01/2011] [Indexed: 01/14/2023]
Abstract
The higher prevalence of thyroid disease in women suggests that estrogen (E2) might be involved in the pathophysiology of thyroid dysfunction. To approach the question of the effect of stromal cells in the modulation of thyroid epithelial cells activity, we established and characterized a homogeneous stromal cell population (TS7 cells) of rat thyroid gland. These fibroblastic cells synthesize the cytoskeleton proteins α-smooth muscle actin and vimentin, produce basement membrane components and express the cytokine transforming growth factor beta 1 (TGF-β1). Here, we hypothesized that the effects of E2 on follicular thyroid cells are mediated by TGF-β1 synthesis and secretion by stromal cells (paracrine action). Thus we investigated the effect of E2 on TGF-β1 synthesis and its signaling pathway in TS7 cells. In addition, we analyzed the role of TGF-β1 signaling pathway as mediator of TS7-PC CL3 thyroid epithelial cells interactions. We report that TS7 stromal cells expressed α and β estrogen receptors (ERα and ERβ). Further, both isoforms of TGF-β1 receptors, TGFRI and TGFRII, were also identified in TS7 cells, suggesting that these cells might be a target for this cytokine in vitro. Treatment of TS7 cells with E2 induced both synthesis and secretion of TGF-β1. This event was followed by phosphorylation of the transcription factor Smad2, a hallmark of TGF-β1 pathway activation. Co-culture of PC CL3 cells onto TS7 cells monolayers yielded round aggregates of PC CL3 cells surrounded by TS7 cells. TS7 cells induced a decrease in iodide uptake by PC CL3 cells, probably by a mechanism involving TGF-β1. Moreover, E2 affected synthesis and organization of the extracellular matrix (ECM) components, tenascin C and chondroitin sulfate, in these co-culture cells. Our results point to the TGF-β1/Smad-2 signaling pathway as a putative target of estrogen actions on thyroid stromal cells and contribute to understanding the interplay between stromal and follicular cells in thyroid physiology.
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Affiliation(s)
- M A V Gantus
- Laboratory of Cellular Interactions, Program of Cellular Biology and Development, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil
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25
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De Paul AL, Gutiérrez S, Sabatino ME, Mukdsi JH, Palmeri CM, Soaje M, Petiti JP, Torres AI. Epidermal growth factor induces a sexually dimorphic proliferative response of lactotroph cells through protein kinase C-ERK1/2-Pit-1 in vitro. Exp Physiol 2010; 96:226-39. [DOI: 10.1113/expphysiol.2010.054502] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Endocrine pituitary cells are neuronlike; they express numerous voltage-gated sodium, calcium, potassium, and chloride channels and fire action potentials spontaneously, accompanied by a rise in intracellular calcium. In some cells, spontaneous electrical activity is sufficient to drive the intracellular calcium concentration above the threshold for stimulus-secretion and stimulus-transcription coupling. In others, the function of these action potentials is to maintain the cells in a responsive state with cytosolic calcium near, but below, the threshold level. Some pituitary cells also express gap junction channels, which could be used for intercellular Ca(2+) signaling in these cells. Endocrine cells also express extracellular ligand-gated ion channels, and their activation by hypothalamic and intrapituitary hormones leads to amplification of the pacemaking activity and facilitation of calcium influx and hormone release. These cells also express numerous G protein-coupled receptors, which can stimulate or silence electrical activity and action potential-dependent calcium influx and hormone release. Other members of this receptor family can activate calcium channels in the endoplasmic reticulum, leading to a cell type-specific modulation of electrical activity. This review summarizes recent findings in this field and our current understanding of the complex relationship between voltage-gated ion channels, ligand-gated ion channels, gap junction channels, and G protein-coupled receptors in pituitary cells.
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Affiliation(s)
- Stanko S Stojilkovic
- Program in Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Building 49, Room 6A-36, 49 Convent Drive, Bethesda, Maryland 20892-4510, USA.
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27
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Fukuoka H, Cooper O, Mizutani J, Tong Y, Ren SG, Bannykh S, Melmed S. HER2/ErbB2 receptor signaling in rat and human prolactinoma cells: strategy for targeted prolactinoma therapy. Mol Endocrinol 2010; 25:92-103. [PMID: 21106881 DOI: 10.1210/me.2010-0353] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Dopamine agonist resistance or intolerance is encountered in approximately 20% of prolactinoma patients. Because human epidermal growth factor receptor 2 (HER2)/ErbB2 is overexpressed in prolactinomas and ErbB receptor ligands regulate prolactin (PRL) gene expression, we tested the role of HER2/ErbB2 in prolactinoma hormone regulation and adenoma cell proliferation to assess the rationale for targeting this receptor for prolactinoma therapy. As we showed prolactinoma HER2 overexpression, we generated constitutively active HER2-stable GH3 cell transfectants (HER2CA). PRL mRNA levels were induced approximately 250-fold and PRL secretion was enhanced 100-fold in HER2CA cells, which also exhibited increased proliferation. Lapatinib, a dual tyrosine kinase inhibitor (TKI) of both epidermal growth factor receptor (EGFR)/ErbB1 and HER2, blocked receptor signaling, and suppressed PRL expression more than gefitinib, a TKI of EGFR/ErbB1. Lapatinib also suppressed colony formation in soft agar more than gefitinib. Oral lapatinib treatment caused tumor shrinkage and serum PRL suppression both in HER2CA transfectant-inoculated Wistar-Furth rats and in estrogen-induced Fischer344 rat prolactinomas. In cultured human cells derived from resected prolactinoma tissue, lapatinib suppressed both PRL mRNA expression and secretion. These results demonstrate that prolactinoma HER2 potently induces PRL and regulates experimental prolactinoma cell proliferation. Because pituitary HER2 signaling is abrogated by TKIs, this receptor could be an effective target for prolactinoma therapy.
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Affiliation(s)
- Hidenori Fukuoka
- Cedars-Sinai Medical Center, Department of Academic Affairs, 8700 Beverly Boulevard Plaza North, Los Angeles, CA 90048, USA
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28
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Santollo J, Katzenellenbogen BS, Katzenellenbogen JA, Eckel LA. Activation of ERα is necessary for estradiol's anorexigenic effect in female rats. Horm Behav 2010; 58:872-7. [PMID: 20807534 PMCID: PMC2982904 DOI: 10.1016/j.yhbeh.2010.08.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 07/07/2010] [Accepted: 08/25/2010] [Indexed: 12/28/2022]
Abstract
While there is considerable evidence that the ovarian hormone estradiol reduces food intake in female rats, it is unclear which estrogen receptor (ER) subtype, ERα or ERβ, mediates this effect. While several studies have demonstrated that activation of ERα, but not ERβ, is sufficient to reduce food intake in ovariectomized (OVX) rats, there are limited data regarding which receptor subtype is necessary. Here we used the selective ERα and ERß antagonists, MPrP and PHTPP, respectively, to investigate this question. We found that antagonism of ERα, but not ERβ, prevented the decrease in food intake following acute administration of estradiol in OVX rats. In addition, antagonism of ERα prevented the estrous-related, phasic reduction in food intake that occurs in response to the rise in circulating levels of estradiol in cycling rats. We conclude that activation of ERα is necessary for the anorexigenic effects of exogenous and endogenous estradiol in female rats.
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Affiliation(s)
- Jessica Santollo
- Program in Neuroscience, Florida State University, Tallahassee, Florida, 32306, USA
| | - Benita S. Katzenellenbogen
- Department of Molecular and Integrative Physiology, Cell and Developmental Biology, University of Illinois, Urbana, Illinois, 61801, USA
| | | | - Lisa A. Eckel
- Program in Neuroscience, Florida State University, Tallahassee, Florida, 32306, USA
- Corresponding author: Department of Psychology, Florida State University, 1107 West Call Street, Tallahassee, FL 32306-4301, Telephone: 850-644-3460, Fax: 850-644-7739,
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Gutiérrez S, Petiti JP, Sosa LDV, Fozzatti L, De Paul AL, Masini-Repiso AM, Torres AI. 17β-oestradiol acts as a negative modulator of insulin-induced lactotroph cell proliferation through oestrogen receptor α, via nitric oxide/guanylyl cyclase/cGMP. Cell Prolif 2010; 43:505-14. [PMID: 20887556 DOI: 10.1111/j.1365-2184.2010.00700.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES 17β-oestradiol interacts with growth factors to modulate lactotroph cell population. However, contribution of isoforms of the oestrogen receptor in these activities is not fully understood. In the present study, we have established participation of α and β oestrogen receptors in effects of 17β-oestradiol on lactotroph proliferation induced by insulin and shown involvement of the NO/sGC/cGMP pathway. MATERIALS AND METHODS Cell cultures were prepared from anterior pituitaries of female rats to evaluate lactotroph cell proliferation using bromodeoxyuridine (BrdUrd) detection, protein expression by western blotting and cGMP by enzyme immunoassay. RESULTS In serum-free conditions, 17β-oestradiol and α and β oestrogen receptor agonists (PPT and DPN) failed to increase numbers of lactotroph cells undergoing mitosis. Co-incubation of 17β-oestradiol/insulin and PPT/insulin significantly decreased lactotroph mitogenic activity promoted by insulin alone. Both ICI 182780 and NOS inhibitors (L-NMMA and L-NAME) induced reversal of the anti-proliferative effect promoted by 17β-oestradiol/insulin and PPT/insulin. Moreover, 17β-oestradiol, PPT and insulin increased sGC α1 protein expression and inhibited β1, whereas co-incubation of 17β-oestradiol/insulin or PPT/insulin induced increases of the two isoforms α1 and β1. 17β-oestradiol and insulin reduced cGMP production, while 17β-oestradiol/insulin co-incubation increased this cyclic nucleotide. CONCLUSIONS Our results suggest that 17β-oestradiol is capable of arresting lactotroph proliferation induced by insulin through ER α with participation of the signalling NO/sGC/cGMP pathway.
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Affiliation(s)
- S Gutiérrez
- Center of Electron Microscopy, Faculty of Medical Sciences, National University of Córdoba, Córdoba, Argentina.
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Hikake T, Hayashi S, Chambon P, Watanabe H, Iguchi T, Sato T. Differential involvement of insulin-like growth factor-I and estrogen on prolactin cells in the mouse anterior pituitary. Exp Biol Med (Maywood) 2010; 235:974-80. [PMID: 20576740 DOI: 10.1258/ebm.2010.009396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Estrogen and insulin-like growth factor-I (IGF-I) stimulate prolactin (PRL) production, release and proliferation of PRL-producing cells (PRL cells) in the anterior pituitary. PRL cells in adult estrogen receptor alpha (ERalpha) knockout (alphaERKO) mice and IGF-I knockout (IGF-IKO) mice are decreased considerably in number. To investigate a correlation between 17beta-estradiol (E2) and IGF-I on PRL production, IGF-I wild-type (WT) or IGF-IKO mice were ovariectomized at day 8 and the number of PRL cells was examined at days 20 and 60. Although PRL cell number at day 20 and WT or IGF-IKO mice ovariectomized at day 8 was similar to that in intact WT or IGF-IKO mice, PRL cells in adult WT or IGF-IKO mice ovariectomized at day 8 were significantly decreased as compared with those in intact WT or IGF-IKO mice. Therefore, estrogen is essential for PRL cell differentiation between days 20 and 60, regardless of IGF-I. While PRL cells in WT ovariectomized mice increased from days 20 to 60, those in IGF-IKO ovariectomized mice did not increase, suggesting that IGF-I modified PRL cell differentiation after day 20. ICI 182,780 (anti-estrogen) treatment canceled an increase of PRL cells in 30-day-old ovariectomized WT mice, indicating that the presence of ERalpha is important. The number of PRL cells in alphaERKO mice was similar to that in WT mice at day 20; however, PRL cells in alphaERKO mice at day 60 were not increased in number from day 20, supporting the idea that estrogen is essential for PRL cell differentiation after day 20. Finally, the percentage of PRL cells in IGF-IKO mice was decreased as compared with that in WT mice at day 20; therefore, IGF-I affects PRL cells before day 20. In conclusion, PRL cell differentiation is differently regulated by E2 and IGF-I depending on the age.
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Chen S, Bangaru MLY, Sneade L, Dunckley JA, Ben-Jonathan N, Kansra S. Epidermal growth factor receptor cross-talks with ligand-occupied estrogen receptor-alpha to modulate both lactotroph proliferation and prolactin gene expression. Am J Physiol Endocrinol Metab 2009; 297:E331-9. [PMID: 19470835 PMCID: PMC2724110 DOI: 10.1152/ajpendo.00133.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both estrogen (E2) and EGF regulate lactotrophs, and we recently demonstrated that EGF phosphorylates S118 on estrogen receptor-alpha (ERalpha) and requires ERalpha to stimulate prolactin (PRL) release. However, the interactions between ligand-occupied ERalpha and activated ErbB1 and its impact on lactotroph function are unknown. Using rat GH3 lactotrophs, we found that both E2 and EGF independently stimulated proliferation and PRL gene expression. Furthermore, their combination resulted in an enhanced stimulatory effect on both cell proliferation and PRL gene expression. Inhibitors of ER as well as ErbB1 blocked the combined effects of E2 and EGF. Pretreatment with UO126 abolished the combined effects, demonstrating Erk1/2 requirement. Although bidirectionality in ER-ErbB1 cross-talk is a well-accepted paradigm, interestingly in lactotrophs, ErbB1 kinase inhibitor failed to block the effect of E2 on proliferation and stimulation of PRL gene expression, suggesting that ER does not require ErbB1 to mediate its effects. Furthermore, E2 did not affect the ability of EGF to induce c-Fos expression or modulate AP-1 activity. However, both E2 and EGF combine to enhance S118 phosphorylation of ERalpha, leading to enhanced E2-mediated estrogen response element transactivation. Taken together, our results suggest that, in lactotrophs, activated ErbB1 phosphorylates ERalpha to enhance the stimulatory effect of E2, thereby providing the molecular basis by which EGF amplifies the response of E2.
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Affiliation(s)
- Shenglin Chen
- Department of Endocrinology, Metabolism and Clinical Nutrition, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Vlotides G, Cooper O, Chen YH, Ren SG, Greenman Y, Melmed S. Heregulin regulates prolactinoma gene expression. Cancer Res 2009; 69:4209-16. [PMID: 19401448 DOI: 10.1158/0008-5472.can-08-4934] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To investigate the role of p185(her2/neu)/ErbB3 signaling in pituitary tumor function, we examined these receptors in human prolactinomas. Immunofluorescent p185(her2/neu) was detected in almost all (seven of eight), and ErbB3 expression in a subset (four of eight) of tumors (seven adenomas and one carcinoma). Quantitative PCR also showed abundant ErbB3 mRNA in tumor specimens derived from a rarely encountered prolactin-cell carcinoma. Activation of p185(c-neu)/ErbB3 signaling with heregulin, the ErbB3 ligand, in rat lacto-somatotroph (GH4C1) tumor cells specifically induced prolactin (PRL) mRNA expression approximately 5-fold and PRL secretion approximately 4-fold, whereas growth hormone expression was unchanged. Heregulin (6 nmol/L) induced tyrosine phosphorylation and ErbB3 and p185(c-neu) heterodimerization, with subsequent activation of intracellular ERK and Akt. The Akt signal was specific to ErbB3 activation by heregulin, and was not observed in response to epidermal growth factor activation of epidermal growth factor receptor. Gefitinib, the tyrosine kinase inhibitor, suppressed heregulin-mediated p185(c-neu)/ErbB3 signaling to PRL. Heregulin induction of PRL was also abrogated by transfecting cells with short interfering RNA directed against ErbB3. Pharmacologic inhibition of heregulin-induced phosphoinositide-3-kinase/Akt (with LY294002) and ERK (with U0126) signaling, as well as short interfering RNA-mediated mitogen-activated protein kinase-1 down-regulation, showed ERK signaling as the primary transducer of heregulin signaling to PRL. These results show ErbB3 expression in human prolactinomas and a novel ErbB3-mediated mechanism for PRL regulation in experimental lactotroph tumors. Targeted inhibition of up-regulated p185(c-neu)/ErbB3 activity could be useful for the treatment of aggressive prolactinomas resistant to conventional therapy.
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Affiliation(s)
- George Vlotides
- Department of Medicine, Cedars-Sinai Medical Center, University of California School of Medicine, Los Angeles, CA, USA
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