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Clevenger CV, Rui H. Breast Cancer and Prolactin - New Mechanisms and Models. Endocrinology 2022; 163:6654897. [PMID: 35922139 PMCID: PMC9419691 DOI: 10.1210/endocr/bqac122] [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] [Received: 11/03/2021] [Indexed: 11/19/2022]
Abstract
The pathogenesis of breast cancer is driven by multiple hormones and growth factors. One of these, prolactin (PRL), contributes to both mammary differentiation and oncogenesis, and yet the basis for these disparate effects has remained unclear. The focus of this review is to examine and place into context 2 recent studies that have provided insight into the roles of PRL receptors and PRL in tumorigenesis and tumor progression. One study provides novel evidence for opposing actions of PRL in the breast being mediated in part by differential PRL receptor (PRLr) isoform utilization. Briefly, homomeric complexes of the long isoform of the PRLr (PRLrL-PRLrL) promotes mammary differentiation, while heteromeric complexes of the intermediate and long PRLr (PRLrI-PRLrL) isoforms trigger mammary oncogenesis. Another study describes an immunodeficient, prolactin-humanized mouse model, NSG-Pro, that facilitates growth of PRL receptor-expressing patient-derived breast cancer xenografts. Evidence obtained with this model supports the interactions of physiological levels of PRL with estrogen and ERBB2 gene networks, the modulatory effects of PRL on drug responsiveness, and the pro-metastatic effects of PRL on breast cancer. This recent progress provides novel concepts, mechanisms and experimental models expected to renew interest in harnessing/exploiting PRLr signaling for therapeutic effects in breast cancer.
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Affiliation(s)
- Charles V Clevenger
- Correspondence: Charles V. Clevenger, Department of Pathology, Virginia Commonwealth University, 1101 E. Marshall St, Sanger 4-006A, Richmond, VA, 23298-06629, USA.
| | - Hallgeir Rui
- Department of Pathology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Dong X, Liu C, Miao J, Lin X, Wang Y, Wang Z, Hou Q. Effect of serotonin on the cell viability of the bovine mammary alveolar cell-T (MAC-T) cell line. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2022; 64:922-936. [PMID: 36287778 PMCID: PMC9574616 DOI: 10.5187/jast.2022.e50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/30/2022] [Accepted: 06/13/2022] [Indexed: 12/02/2022]
Abstract
5-Hydroxytryptamine (5-HT), a monoamine, as a local regulator in the mammary gland is a chemical signal produced by the mammary epithelium cell. In cows, studies have shown that 5-HT is associated with epithelial cell apoptosis during the degenerative phase of the mammary gland. However, studies in other tissues have shown that 5-HT can effectively promote cell viability. Whether 5-HT could have an effect on mammary cell viability in dairy cows is still unknown. The purpose of this study was to determine: (1) effect of 5-HT on the viability of bovine mammary epithelial cells and its related signaling pathways, (2) interaction between prolactin (PRL) and 5-HT on the cell viability. The bovine mammary alveolar cell-T (MAC-T) were cultured with different concentrations of 5-HT for 12, 24, 48 or 72 hours, and then were assayed using cell counting kit-8, polymerase chain reaction (PCR) and immunobloting. The results suggested that 20 μM 5-HT treatment for 12 or 24 h promote cell viability, which was mainly induced by the activation of 5-HT receptor (5-HTR) 1B and 4, because the increase caused by 5-HT vanished when 5-HTR 1B and 4 was blocked by SB224289 and SB204070. And protein expression of mammalian target of rapamycin (mTOR), eukaryotic translation elongation factor 2 (eEF2), janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5) were decreased after blocking 5-HT 1B and 4 receptors. When MAC-T cells were treated with 5-HT and PRL simultaneously for 24 h, both the cell viability and the level of mTOR protein were significantly higher than that cultured with 5-HT or PRL alone. In conclusion, our study suggested that 5-HT promotes the viability of MAC-T cells by 5-HTR 1B and/or 4. Furthermore, there is a reciprocal relationship between PRL and 5-HT.
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Affiliation(s)
- Xusheng Dong
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China
| | - Chen Liu
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China
| | - Jialin Miao
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China
| | - Xueyan Lin
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China
| | - Yun Wang
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China
| | - Zhonghua Wang
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China,Corresponding author: Zhonghua Wang,
Ruminant Nutrition and Physiology Laboratory, College of Animal Science and
Technology, Shandong Agricultural University, Taian, Shandong 271018, China.
Tel: +86-15005485951, E-mail:
| | - Qiuling Hou
- Ruminant Nutrition and Physiology
Laboratory, College of Animal Science and Technology, Shandong Agricultural
University, Taian, Shandong 271018, China,Corresponding author: Qiuling Hou,
Ruminant Nutrition and Physiology Laboratory, College of Animal Science and
Technology, Shandong Agricultural University, Taian, Shandong 271018, China.
Tel: +86-15064175925, E-mail:
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Medicinal Mushroom Leucocalocybe mongolica Imai Extracts Improve Mammary Gland Differentiation in Lactating Rats via Regulating Protein Expression. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:5762847. [PMID: 35761899 PMCID: PMC9233605 DOI: 10.1155/2022/5762847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/27/2022] [Indexed: 11/29/2022]
Abstract
Leucocalocybe mongolica is a known medicinal mushroom in China. It possesses many biological activities. This study investigated the effect of L. mongolica petroleum ether and water extracts (200, 500, and 1,000 mg/kg BW) on mammary gland differentiation during lactation. However, prolactin, growth hormone, progesterone, and estrogen levels were determined in serum by ELISA assay. Immunofluorescence, western blot, and real-time PCR were utilized to evaluate the expression levels of β-casein, α-Lactalbumin, prolactin receptor, progesterone receptor, and STAT-5a. The immunohistochemistry staining was used to detect the presence of steroid receptors. The results showed that petroleum ether and water extracts increased milk yield and milk content of calcium, total fat, total carbohydrate, and total protein. Prolactin and growth hormone levels were significantly upregulated in all treated groups compared with the control group. In contrast, progesterone and estrogen were downregulated. The high doses of petroleum ether and water extracts increased the expression levels of β-Cas, α-Lactalb, PRLR, PR, and STAT-5a. The observation of histological sections showed that the extracts induced higher mammary gland differentiation than the control group. This study is the first to use mushrooms as nutritional supplements to improve milk production and mammary gland differentiation during lactation.
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Seo YA, Lee S, Hennigar SR, Kelleher SL. Prolactin (PRL)-stimulated ubiquitination of ZnT2 mediates a transient increase in zinc secretion followed by ZnT2 degradation in mammary epithelial cells. J Biol Chem 2014; 289:23653-61. [PMID: 25016022 DOI: 10.1074/jbc.m113.531145] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The zinc transporter ZnT2 imports zinc into secretory vesicles and regulates zinc export from the mammary epithelial cell. Mutations in ZnT2 substantially impair zinc secretion into milk. The lactogenic hormone prolactin (PRL) transcriptionally increases ZnT2 expression through the Jak2/STAT5 signaling pathway, increasing zinc accumulation in secretory vesicles and zinc secretion. Herein, we report that PRL post-translationally stimulated ZnT2 ubiquitination, which altered ZnT2 trafficking and augmented vesicular zinc accumulation and secretion from mammary epithelial cells in a transient manner. Ubiquitination then down-regulated zinc secretion by stimulating degradation of ZnT2. Mutagenesis of two N-terminal lysine residues (K4R and K6R) inhibited ZnT2 ubiquitination, vesicular zinc accumulation and secretion, and protein degradation. These findings establish that PRL post-translationally regulates ZnT2-mediated zinc secretion in a multifactorial manner, first by enhancing zinc accumulation in vesicles to transiently enhance zinc secretion and then by activating ubiquitin-dependent ZnT2 degradation. This provides insight into novel mechanisms through which ZnT2 and zinc transport is tightly regulated in mammary epithelial cells.
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Affiliation(s)
- Young Ah Seo
- the Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, and the Departments of Genetics and Complex Diseases and Nutrition, Harvard School of Public Health, Boston, Massachusetts 02115
| | - Sooyeon Lee
- the Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, and From the Departments of Cell and Molecular Physiology
| | - Stephen R Hennigar
- the Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Shannon L Kelleher
- the Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, and From the Departments of Cell and Molecular Physiology, Pharmacology, and Surgery, Penn State Hershey College of Medicine, Hershey, Pennsylvania 17033,
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Scotland PE, Patil M, Belugin S, Henry MA, Goffin V, Hargreaves KM, Akopian AN. Endogenous prolactin generated during peripheral inflammation contributes to thermal hyperalgesia. Eur J Neurosci 2011; 34:745-54. [PMID: 21777304 DOI: 10.1111/j.1460-9568.2011.07788.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Prolactin (PRL) is a hormone and a neuromodulator. It sensitizes TRPV1 (transient receptor potential cation channel subfamily V member 1) responses in sensory neurons, but it is not clear whether peripheral inflammation results in the release of endogenous PRL, or whether endogenous PRL is capable of acting as an inflammatory mediator in a sex-dependent manner. To address these questions, we examined inflammation-induced release of endogenous PRL, and its regulation of thermal hyperalgesia in female and male rats. PRL is expressed in several types of peripheral neuronal and non-neuronal cells, including TRPV1-positive nerve fibers, preadipocytes and activated macrophages/monocytes localized in the vicinity of nerves. Evaluation of PRL levels in hindpaws and plasma indicated that complete Freund's adjuvant (CFA) stimulates release of peripheral, but not systemic, PRL within 6-48 h in both ovariectomized females with estradiol replacement (OVX-E) and intact male rats. The time course of release varies in OVX-E and intact male rats. We next employed the prolactin receptor (PRL-R) antagonist Δ1-9-G129R-hPRL to assess the role of locally produced PRL in nociception. Applied at a ratio of 1 : 1 (PRL:Δ1-9-G129R-hPRL; 40 nm each), this antagonist was able to nearly (≈ 80%) reverse PRL-induced sensitization of capsaicin responses in rat sensory neurons. CFA-induced inflammatory thermal hyperalgesia in OVX-E rat hindpaws was significantly reduced in a dose-dependent manner by the PRL-R antagonist at 6 h but not at 24 h. In contrast, PRL contributed to inflammatory thermal hyperalgesia in intact male rats at 24, but not at 6 h. These findings indicate that inflammation leads to accumulation of endogenous PRL in female and male rats. Furthermore, PRL acts as an inflammatory mediator at different time points for female and intact male rats.
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Affiliation(s)
- Phoebe E Scotland
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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van den Burg EH, Neumann ID. Bridging the gap between GPCR activation and behaviour: oxytocin and prolactin signalling in the hypothalamus. J Mol Neurosci 2010; 43:200-8. [PMID: 20865346 DOI: 10.1007/s12031-010-9452-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 09/13/2010] [Indexed: 01/06/2023]
Abstract
Neuropeptides of the brain are important neuromodulators, controlling behaviour and physiology. They signal through G protein-coupled receptors (GPCR) that couple to complex intracellular signalling pathways. These signalling networks integrate information from multiple sources, resulting in appropriate physiological and behavioural responses to environmental and internal cues. This paper will focus on the neuropeptides oxytocin and prolactin with respect to (1) the regulation of neuroendocrine stress responses and anxiety, and (2) the receptor-mediated molecular mechanisms underlying these actions of the neuropeptides. Besides its significant reproductive functions when released into the bloodstream, brain oxytocin reduces the activity of the hypothalamo-pituitary-adrenal (HPA) axis as well as anxiety-related behaviour in male and female rats. Oxytocin mediates its anxiolytic effect, at least in part, via binding to its GPCR in the hypothalamic paraventricular nucleus, followed by transactivation of the epidermal growth factor receptor, and subsequent activation of a MEK-extracellular signal-regulated kinase (ERK) MAP kinase pathway. Prolactin, by binding to its GPCR receptors, of which there are short and long forms, also activates ERK, and this is necessary for the control of the expression of corticotrophin-releasing hormone-an important regulator of the HPA axis. Liganded oxytocin and prolactin may also recruit other signalling pathways, but how these pathways contribute to the observed behavioural and physiological effects remains to be established. GPCR-mediated oxytocin and prolactin neuronal signalling are illustrative of the complexity of GPCR-activated regulation of appropriate neuroendocrine and behavioural responses to environmental and physiological demands.
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Affiliation(s)
- Erwin H van den Burg
- Behavioural and Molecular Neuroendocrinology, Institute of Zoology, University of Regensburg, 93053 Regensburg, Germany.
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Chen Y, Huang K, Chen KE, Walker AM. Prolactin and estradiol utilize distinct mechanisms to increase serine-118 phosphorylation and decrease levels of estrogen receptor alpha in T47D breast cancer cells. Breast Cancer Res Treat 2009; 120:369-77. [PMID: 19377875 DOI: 10.1007/s10549-009-0400-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 04/06/2009] [Indexed: 02/06/2023]
Abstract
Potential interactions between prolactin (PRL) and estradiol (E2) in breast cancer cells were explored by examining the effect of PRL on estrogen receptor (ER) serine-118 phosphorylation, ER down-regulation, and E2-stimulated cell proliferation. Both E2 and PRL resulted in prolonged ERalpha serine-118 phosphorylation, but used different signaling pathways to achieve this end. Both hormones also decreased the amount of ERalpha, but the mechanisms were different: for E2, the decrease was rapid and resulted from proteasomic degradation, whereas for PRL the decrease was slow and resulted from an effect on levels of ERalpha mRNA. PRL alone had no effect on cell number, but enhanced the increase in number in response to E2. These results are the first to demonstrate similar effects of PRL and E2 on parameters considered key to E2's effects. This suggests heretofore unrecognized and potentially important interactions between these two hormones in the natural history of breast cancer.
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Affiliation(s)
- Yenhao Chen
- Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
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Fang F, Rycyzyn MA, Clevenger CV. Role of c-Myb during prolactin-induced signal transducer and activator of transcription 5a signaling in breast cancer cells. Endocrinology 2009; 150:1597-606. [PMID: 19036881 PMCID: PMC2659289 DOI: 10.1210/en.2008-1079] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 11/14/2008] [Indexed: 01/17/2023]
Abstract
Implicated in the pathogenesis of breast cancer, prolactin (PRL) mediates its function in part through the prolactin receptor (PRLr)-associated Janus kinase 2 (Jak2)/signal transducer and activator of transcription 5 (Stat5) signaling complex. To delineate the mechanisms of Stat5a regulation in breast cancer, transcription factor-transcription factor (TF-TF) array analysis was employed to identify associated transcriptional regulators. These analyses revealed a PRL-inducible association of Stat5a with the transcription factor and protooncogene c-Myb. Confirmatory co-immunoprecipitation studies using lysates from both T47D and MCF7 breast cancer cells revealed a PRL-inducible association between these transcription factors. Ectopic expression of c-Myb enhanced the PRL-induced expression from both composite and synthetic Stat5a-responsive luciferase reporters. Chromatin immunoprecipitation assays also revealed a PRL-inducible association between c-Myb and endogenous Stat5a-responsive CISH promoter, which was associated with an enhanced expression of CISH gene product at the RNA and protein levels. Small interfering RNA-mediated c-Myb knockdown impaired the PRL-induced mRNA expression of five Stat5-responsive genes. DNA binding-defective mutants of c-Myb, incapable of activating expression from a c-Myb-responsive reporter, maintained their ability to enhance a Stat5a-responsive reporter. At a cellular level, ectopic expression of c-Myb resulted in an increase in T47D proliferation. Taken together, these results indicate that c-Myb potentiates Stat5a-driven gene expression, possibly functioning as a Stat5a coactivator, in human breast cancer.
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Affiliation(s)
- Feng Fang
- Department of Pathology, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois 60611, USA
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Blume A, Torner L, Liu Y, Subburaju S, Aguilera G, Neumann ID. Prolactin activates mitogen-activated protein kinase signaling and corticotropin releasing hormone transcription in rat hypothalamic neurons. Endocrinology 2009; 150:1841-9. [PMID: 19022892 PMCID: PMC2659278 DOI: 10.1210/en.2008-1023] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prolactin (PRL) modulates maternal behavior and mediates hypothalamic pituitary adrenal axis inhibition during lactation via PRL receptors in the brain. To identify mechanisms mediating these effects, we examined the effects of PRL on signaling and CRH transcription in hypothalamic neurons in vivo and in vitro. Western blot of hypothalamic proteins from rats receiving intracerebroventricular PRL injection revealed increases in phosphorylation of the MAPK and ERK. Double-staining immunohistochemistry demonstrated phosphorylated ERK localization in parvocellular CRH neurons as well as magnocellular vasopressin and oxytocin neurons of the hypothalamic paraventricular (PVN) and supraoptic nuclei. PRL also induced ERK phosphorylation in vitro in the hypothalamic cell line, 4B, which expresses PRL receptors, and in primary hypothalamic neuronal cultures. Using reporter gene assays in 4B cells, or quantitative RT-PCR for primary transcript in hypothalamic cell cultures, PRL potentiated forskolin-stimulated CRH transcription through activation of the ERK/MAPK pathway. The effect of PRL in hypothalamic cell cultures was unaffected by tetrodotoxin, suggesting a direct effect on CRH neurons. The data show that PRL activates the ERK/MAPK pathway and facilitates CRH transcription in CRH neurons, suggesting that the inhibitory effect of PRL on hypothalamo-pituitary-adrenal axis activity reported in vivo is indirect and probably mediated through modulation of afferent pathways to the PVN. In addition, the prominent stimulatory action of PRL on the ERK/MAPK pathway in the hypothalamic PVN and supraoptic nucleus is likely to mediate neuroplasticity of the neuroendocrine system during lactation.
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Affiliation(s)
- Annegret Blume
- Department of Behavioural and Molecular Neuroendocrinology, Institute of Zoology, University of Regensburg, 93053 Regensburg, Germany
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Oakes SR, Rogers RL, Naylor MJ, Ormandy CJ. Prolactin regulation of mammary gland development. J Mammary Gland Biol Neoplasia 2008; 13:13-28. [PMID: 18219564 DOI: 10.1007/s10911-008-9069-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2007] [Accepted: 01/02/2008] [Indexed: 10/22/2022] Open
Abstract
Mammary morphogenesis is orchestrated with other reproductive events by pituitary-driven changes to the systemic hormone environment, initiating the formation of a mammary ductal network during puberty and the addition of secretory alveoli during pregnancy. Prolactin is the major driver of development during pregnancy via regulation of ovarian progesterone production (in many species) and direct effects on mammary epithelial cells (in all species). Together these hormones regulate two aspects of development that are the subject of intense interest: (1) a genomic regulatory network that integrates many additional spatial and temporal cues to control gene expression and (2), the activity of a stem and progenitor cell hierarchy. Amalgamation of these two aspects will increase our understanding of cell proliferation and differentiation within the mammary gland, with clear application to our attempts to control breast cancer. Here we focus on providing an over-view of prolactin action during development of the model murine mammary gland.
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Affiliation(s)
- Samantha R Oakes
- Development group, Cancer Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW, 2010, Australia
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Dupont J, Renou JP, Shani M, Hennighausen L, LeRoith D. PTEN overexpression suppresses proliferation and differentiation and enhances apoptosis of the mouse mammary epithelium. J Clin Invest 2002; 110:815-25. [PMID: 12235113 PMCID: PMC151121 DOI: 10.1172/jci13829] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The phosphatase PTEN regulates growth, adhesion, and apoptosis, among many other cell processes. To investigate its role during mouse mammary gland development, we generated MK-PTEN, a transgenic mouse model in which human PTEN is overexpressed in ductal and alveolar mammary epithelium during puberty, pregnancy, lactation, and involution. No obvious phenotype was observed in mammary tissue of pubescent virgin mice. However, MK-PTEN females could not lactate normally, and approximately 30% of pups died, with survivors exhibiting growth retardation. Transgenic offspring nursed by wild-type foster mothers, conversely, developed normally. This phenotype is consistent with a reduced number of alveolar epithelial cells due to a decrease in cell proliferation and an increase in apoptosis. Using mammary-enriched cDNA microarrays, we identified several genes that were preferentially expressed in MK-PTEN mammary tissue, including the IGF-binding protein-5 (Igfbp5) gene, and others whose expression was reduced, including the genes for c-Jun amino-terminal kinase. Secretory epithelial cell differentiation was impaired, as measured by the expression of specific milk protein genes. MK-PTEN mice also exhibited a 50% decrease in the phosphorylation state of Akt. Taken together, these results suggest that PTEN controls mammary gland development and, consequently, lactation.
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Affiliation(s)
- Joëlle Dupont
- Section on Molecular and Cellular Physiology, Clinical Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland 20892, USA
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Dupont J, Renou JP, Shani M, Hennighausen L, LeRoith D. PTEN overexpression suppresses proliferation and differentiation and enhances apoptosis of the mouse mammary epithelium. J Clin Invest 2002. [DOI: 10.1172/jci0213829] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
Within the immune system, multiple isoforms of the human prolactin receptor (PRLr) serve to mediate the effects of its ligand (PRL). Now numbering four, these isoforms are structurally and functionally distinct, demonstrating significant differences in ligand affinities, kinetics of transduction and the transduction proteins activated. The proximal transduction pathways activated during PRLr-associated signaling include the tyrosine kinases Jak2, Fyn and Tec, the phosphatase SHP-2, the guanine nucleotide exchange factor Vav, and the signaling suppressor SOCS. Differential activation of these pathways may contribute to the pleiotropism of PRL action in tissues of the immune system.
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Affiliation(s)
- C V Clevenger
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Medical Center, Philadelphia 19066, USA.
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Craven AJ, Ormandy CJ, Robertson FG, Wilkins RJ, Kelly PA, Nixon AJ, Pearson AJ. Prolactin signaling influences the timing mechanism of the hair follicle: analysis of hair growth cycles in prolactin receptor knockout mice. Endocrinology 2001; 142:2533-9. [PMID: 11356702 DOI: 10.1210/endo.142.6.8179] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pituitary PRL regulates seasonal hair follicle growth cycles in many mammals. Here we present the first evidence implicating PRL in the nonseasonal, wave-like pelage replacement of laboratory mice. In this study we show that messenger RNA transcripts encoding the one long and two short forms of PRL receptor are present in the skin of adult and neonate mice. The receptor protein was immunolocalized to the hair follicle as well as the epidermis and sebaceous glands. Furthermore, PRL messenger RNA was detected within skin extracts, suggesting a possible autocrine/paracrine role. Analysis of the hair growth phenotype of PRL gene-disrupted mice (PRLR(-/-)) revealed a change in the timing of hair cycling events. Although no hair follicle development differences were noted in PRLR(-/-) neonates, observations of the second generation of hair growth revealed PRLR(-/-) mice molted earlier than wild types (PRLR(+/+)). The advance was greater in females (29 days) than in males (4 days), resulting in the elimination of the sexual dimorphism associated with murine hair replacement. Heterozygotes were intermediate between PRLR(-/-) and PRLR(+/+) mice in molt onset. Once initiated, the pattern and progression of the molt across the body were similar in all genotypes. Although all fiber types were present and appeared structurally normal, PRLR(-/-) mice had slightly longer and coarser hair than wild types. These findings demonstrate that PRL has an inhibitory effect on murine hair cycle events. The pituitary PRL regulation of hair follicle cycles observed in seasonally responsive mammals may be a result of pituitary PRL interacting with a local regulatory mechanism.
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Affiliation(s)
- A J Craven
- New Zealand Pastoral Agriculture Research Institute, Hamilton 2020, New Zealand.
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Clevenger CV, Rycyzyn MA, Syed F, Kline JB. Prolactin Receptor Signal Transduction. PROLACTIN 2001. [DOI: 10.1007/978-1-4615-1683-5_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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