1
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Hue-Beauvais C, Laubier J, Brun N, Houtia I, Jaffrezic F, Bevilacqua C, Le Provost F, Charlier M. Puberty is a critical window for the impact of diet on mammary gland development in the rabbit. Dev Dyn 2019; 248:948-960. [PMID: 31348557 PMCID: PMC6790954 DOI: 10.1002/dvdy.91] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 07/12/2019] [Accepted: 07/17/2019] [Indexed: 02/06/2023] Open
Abstract
Background Nutritional changes can affect future lactation efficiency. In a rabbit model, an obesogenic diet initiated before puberty and pursued throughout pregnancy enhances mammary differentiation, but when started during the neonatal period can cause abnormal mammary development in early pregnancy. The aim of this study was to investigate the impact of an unbalanced diet administered during the pubertal period only. Results Consuming an obesogenic diet at puberty did not affect either metabolic parameters or certain maternal reproductive parameters at the onset of adulthood. In contrast, at Day 8 of pregnancy, epithelial tissue showed a lower proliferation rate in obesogenic‐diet fed rabbits than in control‐diet fed rabbits. Wap and Cx26 genes, mammary epithelial cell differentiation markers, were upregulated although Wap protein level remained unchanged. However, the expression of genes involved in lipid metabolism and in alveolar formation was not modified. Conclusion Taken together, our results demonstrate that the consumption for 5 weeks of an obesogenic diet during the pubertal period initiates mammary structure modifications and affects mammary epithelial cell proliferation and differentiation. Our findings highlight the potentially important role played by unbalanced nutrition during critical early‐life windows in terms of regulating mammary epithelial cell differentiation and subsequent function in adulthood. Our results demonstrate that the consumption for five weeks of an obesogenic diet during the pubertal period initiates mammary structure modifications and affects mammary epithelial cell proliferation and differentiation. Our findings highlight the potentially important role played by unbalanced nutrition during critical early‐life windows in terms of regulating mammary epithelial cell differentiation and subsequent function in adulthood.
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Affiliation(s)
- Cathy Hue-Beauvais
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Johann Laubier
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Nicolas Brun
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Inès Houtia
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Florence Jaffrezic
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Claudia Bevilacqua
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | | | - Madia Charlier
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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2
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Fostok SF, El-Sibai M, El-Sabban M, Talhouk RS. Gap Junctions and Wnt Signaling in the Mammary Gland: a Cross-Talk? J Mammary Gland Biol Neoplasia 2019; 24:17-38. [PMID: 30194659 DOI: 10.1007/s10911-018-9411-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/03/2018] [Indexed: 12/21/2022] Open
Abstract
Connexins (Cxs), the building blocks of gap junctions (GJs), exhibit spatiotemporal patterns of expression and regulate the development and differentiation of the mammary gland, acting via channel-dependent and channel-independent mechanisms. Impaired Cx expression and localization are reported in breast cancer, suggesting a tumor suppressive role for Cxs. The signaling events that mediate the role of GJs in the development and tumorigenesis of the mammary gland remain poorly identified. The Wnt pathways, encompassing the canonical or the Wnt/β-catenin pathway and the noncanonical β-catenin-independent pathway, also play important roles in those processes. Indeed, aberrant Wnt signaling is associated with breast cancer. Despite the coincident roles of Cxs and Wnt pathways, the cross-talk in the breast tissue is poorly defined, although this is reported in a number of other tissues. Our previous studies revealed a channel-independent role for Cx43 in inducing differentiation or suppressing tumorigenesis of mammary epithelial cells by acting as a negative regulator of the Wnt/β-catenin pathway. Here, we provide a brief overview of mammary gland development, with emphasis on the role of Cxs in development and tumorigenesis of this tissue. We also discuss the role of Wnt signaling in similar contexts, and review the literature illustrating interplay between Cxs and Wnt pathways.
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Affiliation(s)
- Sabreen F Fostok
- Department of Biology, Faculty of Arts and Sciences, American University of Beirut (AUB), P.O. Box: 11-0236, Beirut, Lebanon
| | - Mirvat El-Sibai
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University (LAU), Beirut, Lebanon
| | - Marwan El-Sabban
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut (AUB), Beirut, Lebanon
| | - Rabih S Talhouk
- Department of Biology, Faculty of Arts and Sciences, American University of Beirut (AUB), P.O. Box: 11-0236, Beirut, Lebanon.
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3
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Thiagarajan PS, Sinyuk M, Turaga SM, Mulkearns-Hubert EE, Hale JS, Rao V, Demelash A, Saygin C, China A, Alban TJ, Hitomi M, Torre-Healy LA, Alvarado AG, Jarrar A, Wiechert A, Adorno-Cruz V, Fox PL, Calhoun BC, Guan JL, Liu H, Reizes O, Lathia JD. Cx26 drives self-renewal in triple-negative breast cancer via interaction with NANOG and focal adhesion kinase. Nat Commun 2018; 9:578. [PMID: 29422613 PMCID: PMC5805730 DOI: 10.1038/s41467-018-02938-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 01/09/2018] [Indexed: 12/18/2022] Open
Abstract
Tumors adapt their phenotypes during growth and in response to therapies through dynamic changes in cellular processes. Connexin proteins enable such dynamic changes during development, and their dysregulation leads to disease states. The gap junction communication channels formed by connexins have been reported to exhibit tumor-suppressive functions, including in triple-negative breast cancer (TNBC). However, we find that connexin 26 (Cx26) is elevated in self-renewing cancer stem cells (CSCs) and is necessary and sufficient for their maintenance. Cx26 promotes CSC self-renewal by forming a signaling complex with the pluripotency transcription factor NANOG and focal adhesion kinase (FAK), resulting in NANOG stabilization and FAK activation. This FAK/NANOG-containing complex is not formed in mammary epithelial or luminal breast cancer cells. These findings challenge the paradigm that connexins are tumor suppressors in TNBC and reveal a unique function for Cx26 in regulating the core self-renewal signaling that controls CSC maintenance. Connexin proteins are usually considered as tumor suppressors. Here, the authors show that connexin 26 (Cx26) regulates the self-renewal of breast cancer stem cells via a ternary complex with FAK and NANOG.
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Affiliation(s)
- Praveena S Thiagarajan
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA.,Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, 44195, USA
| | - Maksim Sinyuk
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Soumya M Turaga
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Erin E Mulkearns-Hubert
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - James S Hale
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Vinay Rao
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Abeba Demelash
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Caner Saygin
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Arnab China
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Tyler J Alban
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA.,Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, 44195, USA
| | - Masahiro Hitomi
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA.,Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, 44195, USA
| | - Luke A Torre-Healy
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Alvaro G Alvarado
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Awad Jarrar
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Andrew Wiechert
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA
| | - Valery Adorno-Cruz
- Case Comprehensive Cancer Center, Cleveland, OH, 44195, USA.,Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,Departments of Pharmacology and Medicine, Northwestern University School of Medicine, Chicago, IL, 60611, USA
| | - Paul L Fox
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA.,Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, 44195, USA.,Case Comprehensive Cancer Center, Cleveland, OH, 44195, USA
| | | | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Huiping Liu
- Case Comprehensive Cancer Center, Cleveland, OH, 44195, USA.,Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,Departments of Pharmacology and Medicine, Northwestern University School of Medicine, Chicago, IL, 60611, USA
| | - Ofer Reizes
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA. .,Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, 44195, USA. .,Case Comprehensive Cancer Center, Cleveland, OH, 44195, USA.
| | - Justin D Lathia
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44915, USA. .,Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, 44195, USA. .,Case Comprehensive Cancer Center, Cleveland, OH, 44195, USA.
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4
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Du ZJ, Cui GQ, Zhang J, Liu XM, Zhang ZH, Jia Q, Ng JC, Peng C, Bo CX, Shao H. Inhibition of gap junction intercellular communication is involved in silica nanoparticles-induced H9c2 cardiomyocytes apoptosis via the mitochondrial pathway. Int J Nanomedicine 2017; 12:2179-2188. [PMID: 28356735 PMCID: PMC5367603 DOI: 10.2147/ijn.s127904] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Gap junction intercellular communication (GJIC) between cardiomyocytes is essential for synchronous heart contraction and relies on connexin-containing channels. Connexin 43 (Cx43) is a major component involved in GJIC in heart tissue, and its abnormal expression is closely associated with various cardiac diseases. Silica nanoparticles (SNPs) are known to induce cardiovascular toxicity. However, the mechanisms through which GJIC plays a role in cardiomyocytes apoptosis induced by SNPs remain unknown. The aim of the present study is to determine whether SNPs-decreased GJIC promotes apoptosis in rat cardiomyocytes cell line (H9c2 cells) via the mitochondrial pathway using CCK-8 Kit, scrape-loading dye transfer technique, Annexin V/PI double-staining assays, and Western blot analysis. The results showed that SNPs elicited cytotoxicity in H9c2 cells in a time- and concentration-dependent manner. SNPs also reduced GJIC in H9c2 cells in a concentration-dependent manner through downregulation of Cx43 and upregulation of P-Cx43. Inhibition of gap junctions by gap junction blocker carbenoxolone disodium resulted in decreased survival and increased apoptosis, whereas enhancement of the gap junctions by retinoic acid led to enhanced survival but decreased apoptosis. Furthermore, SNPs-induced apoptosis through the disrupted functional gap junction was correlated with abnormal expressions of the proteins involved in the mitochondrial pathway-related apoptosis such as Bcl-2/Bax, cytochrome C, Caspase-9, and Caspase-3. Taken together, our results provide the first evidence that SNPs-decreased GJIC promotes apoptosis in cardiomyocytes via the mitochondrial pathway. In addition, downregulation of GJIC by SNPs in cardiomyocytes is mediated through downregulation of Cx43 and upregulation of P-Cx43. These results suggest that in rat cardiomyocytes cell line, GJIC plays a protective role in SNPs-induced apoptosis and that GJIC may be one of the targets for SNPs-induced biological effects.
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Affiliation(s)
- Zhong-Jun Du
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences
| | - Guan-Qun Cui
- Department of Respiratory Medicine, Qilu Children's Hospital of Shandong University, Jinan
| | - Juan Zhang
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences
| | - Xiao-Mei Liu
- Department of Radiation Chemistry and Toxicology, School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Zhi-Hu Zhang
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences
| | - Qiang Jia
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences
| | - Jack C Ng
- National Research Centre for Environmental Toxicology-Entox, The University of Queensland, Brisbane, QLD, Australia
| | - Cheng Peng
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences; National Research Centre for Environmental Toxicology-Entox, The University of Queensland, Brisbane, QLD, Australia
| | - Cun-Xiang Bo
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences
| | - Hua Shao
- Department of Toxicology, Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences
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5
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Cx26 knockout predisposes the mammary gland to primary mammary tumors in a DMBA-induced mouse model of breast cancer. Oncotarget 2016; 6:37185-99. [PMID: 26439696 PMCID: PMC4741923 DOI: 10.18632/oncotarget.5953] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/17/2015] [Indexed: 11/28/2022] Open
Abstract
Down-regulation of the gap junction protein connexin26 (Cx26) is an early event following breast cancer onset and has led to Cx26 being classically described as a tumor suppressor. Interestingly, mutations in theCx26 gene (GJB2) reduce or ablate Cx26 gap junction channel function and are the most common cause of genetic deafness. It is unknown if patients with loss-of-function GJB2 mutations have a greater susceptibility to breast tumorigenesis or aggressive breast cancer progression. To investigate these possibilities, 7, 12-dimethylbenz[α]anthracene (DMBA)-induced tumor development was evaluated in BLG-Cre; Cx26fl/fl mice expressing Cre under the β-Lactoglobulin promoter (Cre+) compared to Cx26fl/fl controlmice (Cre-) following pituitary isograft driven Cx26 knockout. A significantly increased number of DMBA-treated Cre+ mice developed primary mammary tumors, as well as developed multiple tumors, compared to Cre- mice. Primary tumors of Cre+ mice were of multiple histological subtypes and had similar palpable tumour onset and growth rate compared to tumors from Cre- mice. Lungs were evaluated for evidence of metastases revealing a similar percentage of lung metastases in Cre+ and Cre- mice. Together, our results suggest that loss of Cx26 predisposes the mammary gland to chemically induced mammary tumour formation which may have important implications to patients with GJB2 mutations.
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6
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Loss of Panx1 Impairs Mammary Gland Development at Lactation: Implications for Breast Tumorigenesis. PLoS One 2016; 11:e0154162. [PMID: 27099931 PMCID: PMC4839729 DOI: 10.1371/journal.pone.0154162] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/08/2016] [Indexed: 12/03/2022] Open
Abstract
Pannexin1 (Panx1) subunits oligomerize to form large-pore channels between the intracellular and extracellular milieu that have been shown to regulate proliferation, differentiation and cell death mechanisms. These key cellular responses are ultimately necessary for normal tissue development and function but the role of Panx1 in development, differentiation and function in many tissues remains unexplored, including that of the breast. Panx1 was identified to be expressed in the mammary gland through western blot and immunofluorescent analysis and is dynamically upregulated during pregnancy and lactation. In order to evaluate the role of Panx1 in the context of mammary gland development and function, Panx1-/- mice were evaluated in comparison to wild-type mice in the mammary glands of virgin, lactating and involuting mice. Our results revealed that Panx1 ablation did not affect virgin or involuting mammary glands following histological and whole mount analysis. Panx1 was necessary for timely alveolar development during early lactation based on a decreased number of alveolar lumen following histological analysis and reduced proliferation following Ki67 immunofluorescent labelling. Importantly, the loss of Panx1 in lactating mammary glands did not overtly affect epithelial or secretory differentiation of the mammary gland suggesting that Panx1 is not critical in normal mammary gland function. In addition, PANX1 mRNA expression was correlated with negative clinical outcomes in patients with breast cancer using in silico arrays. Together, our results suggest that Panx1 is necessary for timely alveolar development following the transition from pregnancy to lactation, which may have implications extending to patients with breast cancer.
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7
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Metser G, Shin HY, Wang C, Yoo KH, Oh S, Villarino AV, O'Shea JJ, Kang K, Hennighausen L. An autoregulatory enhancer controls mammary-specific STAT5 functions. Nucleic Acids Res 2015; 44:1052-63. [PMID: 26446995 PMCID: PMC4756855 DOI: 10.1093/nar/gkv999] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/22/2015] [Indexed: 01/06/2023] Open
Abstract
Signal Transducers and Activators of Transcription (STATs) are principal transcription factors downstream of cytokine receptors. Although STAT5A is expressed in most tissues it remains to be understood why its premier, non-redundant functions are restricted to prolactin-induced mammary gland development and function. We report that the ubiquitously expressed Stat5a/b locus is subject to additional lineage-specific transcriptional control in mammary epithelium. Genome-wide surveys of epigenetic status and transcription factor occupancy uncovered a putative mammary-specific enhancer within the intergenic sequences separating the two Stat5 genes. This region exhibited several hallmarks of genomic enhancers, including DNaseI hypersensitivity, H3K27 acetylation and binding by GR, NFIB, ELF5 and MED1. Mammary-specific STAT5 binding was obtained at two canonical STAT5 binding motifs. CRISPR/Cas9-mediated genome editing was used to delete these sites in mice and determine their biological function. Mutant animals exhibited an 80% reduction of Stat5 levels in mammary epithelium and a concomitant reduction of STAT5-dependent gene expression. Transcriptome analysis identified a class of mammary-restricted genes that was particularly dependent on high STAT5 levels as a result of the intergenic enhancer. Taken together, the mammary-specific enhancer enables a positive feedback circuit that contributes to the remarkable abundance of STAT5 and, in turn, to the efficacy of STAT5-dependent mammary physiology.
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Affiliation(s)
- Gil Metser
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ha Youn Shin
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chaochen Wang
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kyung Hyun Yoo
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sumin Oh
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA Department of Microbiology, Dankook University, Cheonan, Chungnam 330-714, Republic of Korea
| | - Alejandro V Villarino
- Molecular Immunology and Inflammation Branch, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - John J O'Shea
- Molecular Immunology and Inflammation Branch, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Keunsoo Kang
- Department of Microbiology, Dankook University, Cheonan, Chungnam 330-714, Republic of Korea
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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8
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M Kidder G, Winterhager E. Physiological roles of connexins in labour and lactation. Reproduction 2015; 150:R129-36. [PMID: 26150552 DOI: 10.1530/rep-15-0134] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 07/06/2015] [Indexed: 01/08/2023]
Abstract
The connexin family of proteins are best known as oligomerizing to form intercellular membrane channels (gap junctions) that metabolically and ionically couple cells to allow for coordinated cellular function. Nowhere in the body is this role better illustrated than in the uterine smooth muscle during parturition, where gap junctions conduct the contraction wave throughout the tissue to deliver the baby. Parturition is followed by the onset of lactation with connexins contributing to both the dramatic reorganization of mammary gland tissue leading up to lactation and the smooth muscle contraction of the myoepithelial cells which extrudes the milk. This review summarizes what is known about the expression and roles of individual connexin family members in the uterus during labour and in the mammary glands during development and lactation. Connexin loss or malfunction in mammary glands and the uterus can have serious implications for the health of both the mother and the newborn baby.
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Affiliation(s)
- Gerald M Kidder
- Department of Physiology and PharmacologySchulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario N6A 5C1, CanadaInstitute of Molecular BiologyUniversity of Duisburg-Essen, University Clinics, 45211 Essen, Germany
| | - Elke Winterhager
- Department of Physiology and PharmacologySchulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario N6A 5C1, CanadaInstitute of Molecular BiologyUniversity of Duisburg-Essen, University Clinics, 45211 Essen, Germany
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9
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Stewart MKG, Simek J, Laird DW. Insights into the role of connexins in mammary gland morphogenesis and function. Reproduction 2015; 149:R279-90. [DOI: 10.1530/rep-14-0661] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/19/2015] [Indexed: 12/15/2022]
Abstract
Gap junctions formed of connexin subunits link adjacent cells by direct intercellular communication that is essential for normal tissue homeostasis in the mammary gland. The mammary gland undergoes immense remodeling and requires exquisite regulation to control the proliferative, differentiating, and cell death mechanisms regulating gland development and function. The generation of novel genetically modified mice with reduced or ablated connexin function within the mammary gland has advanced our understanding of the role of gap junctions during the complex and dynamic process of mammary gland development. These studies have revealed an important stage-specific role for Cx26 (GJA1) and Cx43 (GJB2), while Cx30 (GJB6) and Cx32 (Gjb1) can be eliminated without compromising the gland. Yet, there remain gaps in our understanding of the role of mammary gland gap junctions.
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10
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Xiao D, Chen S, Shao Q, Chen J, Bijian K, Laird DW, Alaoui-Jamali MA. Dynamin 2 interacts with connexin 26 to regulate its degradation and function in gap junction formation. Int J Biochem Cell Biol 2014; 55:288-97. [DOI: 10.1016/j.biocel.2014.09.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 09/09/2014] [Accepted: 09/19/2014] [Indexed: 11/16/2022]
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Stewart MKG, Plante I, Bechberger JF, Naus CC, Laird DW. Mammary gland specific knockdown of the physiological surge in Cx26 during lactation retains normal mammary gland development and function. PLoS One 2014; 9:e101546. [PMID: 24988191 PMCID: PMC4079510 DOI: 10.1371/journal.pone.0101546] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 06/08/2014] [Indexed: 12/17/2022] Open
Abstract
Connexin26 (Cx26) is the major Cx protein expressed in the human mammary gland and is up-regulated during pregnancy while remaining elevated throughout lactation. It is currently unknown if patients with loss-of-function Cx26 mutations that result in hearing loss and skin diseases have a greater susceptibility to impaired breast development. To investigate if Cx26 plays a critical role in mammary gland development and differentiation, a novel Cx26 conditional knockout mouse model was generated by crossing Cx26fl/fl mice with mice expressing Cre under the β-Lactoglobulin promoter. Conditional knockdown of Cx26 from the mammary gland resulted in a dramatic reduction in detectable gap junction plaques confirmed by a significant ∼65-70% reduction in Cx26 mRNA and protein throughout parturition and lactation. Interestingly, this reduction was accompanied by a decrease in mammary gland Cx30 gap junction plaques at parturition, while no change was observed for Cx32 or Cx43. Whole mount, histological and immunofluorescent assessment of breast tissue revealed comparatively normal lobuloalveolar development following pregnancy in the conditionally knockdown mice compared to control mice. In addition, glands from genetically-modified mice were capable of producing milk proteins that were evident in the lumen of alveoli and ducts at similar levels as controls, suggesting normal gland function. Together, our results suggest that low levels of Cx26 expression throughout pregnancy and lactation, and not the physiological surge in Cx26, is sufficient for normal gland development and function.
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Affiliation(s)
- Michael K G Stewart
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | | | - John F Bechberger
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christian C Naus
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dale W Laird
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
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12
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NHERF1/EBP50 controls lactation by establishing basal membrane polarity complexes with prolactin receptor. Cell Death Dis 2012; 3:e391. [PMID: 22992649 PMCID: PMC3461366 DOI: 10.1038/cddis.2012.131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The development of the lactating mammary gland is a complex multifactorial process occurring in mammals during pregnancy. We show here that this process requires NHERF1/EBP50 (Na/H exchanger regulatory factor 1/ERM-binding phosphoprotein 50) expression and that successful lactation depends on NHERF1 allele copy number, with rates of 50 and 20% in NHERF1(+/−) and (−/−) mice, respectively. The prolactin receptor (PRLR)-STAT5 signaling provides the central axis triggering the differentiation of secretory mammary alveolar cells. In successfully lactating glands, NHERF1 is massively upregulated and forms complexes with PRLR, but also with β-catenin, E-cadherin and ezrin at the alveolar basal membrane, establishing basal polarity. In NHERF1-deficient glands, the basal polarity is disrupted, the PRLR levels and basal membrane localization are abolished, and the downstream STAT5 activation collapses with consequent reduction of milk protein synthesis. NHERF1/EBP50, a protein deregulated in breast cancer, thus emerges as an important physiological mediator of milk secretion, by engagement of PRLR in multimeric complexes at the alveolar basal membrane with subsequent network activation leading to cell differentiation.
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Feuermann Y, Robinson GW, Zhu BM, Kang K, Raviv N, Yamaji D, Hennighausen L. The miR-17/92 cluster is targeted by STAT5 but dispensable for mammary development. Genesis 2012; 50:665-71. [PMID: 22389215 PMCID: PMC3560854 DOI: 10.1002/dvg.22023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/22/2012] [Accepted: 02/23/2012] [Indexed: 11/06/2022]
Abstract
Genome wide analysis revealed the miR-17/92 cluster as a STAT5 target. This cluster encodes six microRNAs, which predictably target genes that play a role in mammary gland development. In this study, we have deleted the miR-17/92 cluster in mammary stem cells and evaluated in the mouse its function during mammary gland development. Loss of the miR-17/92 cluster did not affect mammary development from prepuberty to lactation. Our studies demonstrated that, while expression of the miR-17/92 cluster is under control of the key mammary transcription factor STAT5, its presence is not required for normal mammary development or lactation.
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Affiliation(s)
- Yonatan Feuermann
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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14
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Kar R, Batra N, Riquelme MA, Jiang JX. Biological role of connexin intercellular channels and hemichannels. Arch Biochem Biophys 2012; 524:2-15. [PMID: 22430362 PMCID: PMC3376239 DOI: 10.1016/j.abb.2012.03.008] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/16/2012] [Accepted: 03/06/2012] [Indexed: 12/11/2022]
Abstract
Gap junctions (GJ) and hemichannels (HC) formed from the protein subunits called connexins are transmembrane conduits for the exchange of small molecules and ions. Connexins and another group of HC-forming proteins, pannexins comprise the two families of transmembrane proteins ubiquitously distributed in vertebrates. Most cell types express more than one connexin or pannexin. While connexin expression and channel activity may vary as a function of physiological and pathological states of the cell and tissue, only a few studies suggest the involvement of pannexin HC in acquired pathological conditions. Importantly, genetic mutations in connexin appear to interfere with GJ and HC function which results in several diseases. Thus connexins could serve as potential drug target for therapeutic intervention. Growing evidence suggests that diseases resulting from HC dysfunction might open a new direction for development of specific HC reagents. This review provides a comprehensive overview of the current studies of GJ and HC formed by connexins and pannexins in various tissue and organ systems including heart, central nervous system, kidney, mammary glands, ovary, testis, lens, retina, inner ear, bone, cartilage, lung and liver. In addition, present knowledge of the role of GJ and HC in cell cycle progression, carcinogenesis and stem cell development is also discussed.
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Affiliation(s)
| | | | - Manuel A Riquelme
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900
| | - Jean X. Jiang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229-3900
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15
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Crispino G, Di Pasquale G, Scimemi P, Rodriguez L, Galindo Ramirez F, De Siati RD, Santarelli RM, Arslan E, Bortolozzi M, Chiorini JA, Mammano F. BAAV mediated GJB2 gene transfer restores gap junction coupling in cochlear organotypic cultures from deaf Cx26Sox10Cre mice. PLoS One 2011; 6:e23279. [PMID: 21876744 PMCID: PMC3158073 DOI: 10.1371/journal.pone.0023279] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 07/11/2011] [Indexed: 11/24/2022] Open
Abstract
The deafness locus DFNB1 contains GJB2, the gene encoding connexin26 and GJB6, encoding connexin30, which appear to be coordinately regulated in the inner ear. In this work, we investigated the expression and function of connexin26 and connexin30 from postnatal day 5 to adult age in double transgenic Cx26(Sox10Cre) mice, which we obtained by crossing connexin26 floxed mice with a deleter Sox10-Cre line. Cx26(Sox10Cre) mice presented with complete connexin26 ablation in the epithelial gap junction network of the cochlea, whereas connexin30 expression was developmentally delayed; immunolabeling patterns for both connexins were normal in the cochlear lateral wall. In vivo electrophysiological measurements in Cx26(Sox10Cre) mice revealed profound hearing loss accompanied by reduction of endocochlear potential, and functional experiments performed in postnatal cochlear organotypic cultures showed impaired gap junction coupling. Transduction of these cultures with a bovine adeno associated virus vector restored connexin26 protein expression and rescued gap junction coupling. These results suggest that restoration of normal connexin levels by gene delivery via recombinant adeno associated virus could be a way to rescue hearing function in DFNB1 mouse models and, in future, lead to the development of therapeutic interventions in humans.
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Affiliation(s)
- Giulia Crispino
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
| | - Giovanni Di Pasquale
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Pietro Scimemi
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Laura Rodriguez
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
| | - Fabian Galindo Ramirez
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
| | - Romolo Daniele De Siati
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Rosa Maria Santarelli
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Edoardo Arslan
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Mario Bortolozzi
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
- Istituto CNR di Neuroscienze, Padova, Italy
| | - John A. Chiorini
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Fabio Mammano
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
- Istituto CNR di Neuroscienze, Padova, Italy
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16
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Baxley SE, Jiang W, Serra R. Misexpression of wingless-related MMTV integration site 5A in mouse mammary gland inhibits the milk ejection response and regulates connexin43 phosphorylation. Biol Reprod 2011; 85:907-15. [PMID: 21753195 DOI: 10.1095/biolreprod.111.091645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Wingless-related MMTV integration site 5A (Wnt5a) is a noncanonical signaling WNT that is expressed in every stage of mouse mammary gland development except lactation. Using slow release pellets containing WNT5A as well as Wnt5a-null tissue, we previously showed that WNT5A acts to limit mammary development. Here, we generated transgenic mice that overexpress WNT5A in the mammary epithelium using the mouse mammary tumor virus promoter (M5a mice). Lactation was impaired in two high WNT5A-expressing lines. Lactation defects could not be explained by differences in apoptosis, lineage differentiation, milk synthesis, or secretion. Instead, misexpression of WNT5A led to a failure in oxytocin response and milk ejection. Noting the similarity between the M5a phenotype and that of mice with a mutation in connexin43 (Cx43; official gene symbol Gja1), we examined Cx43 phosphorylation and localization in M5a mice. In wild-type mice, Cx43 switched from a phosphorylated to a more hypophosphorylated form after parturition. In contrast, the phosphorylated form of Cx43 was maintained after parturition in M5a mice. Using a nontumorigenic breast cell line, MCF10A, we showed that, in addition to increasing the levels of phosphorylation of Cx43 on serine-368, ectopic expression of WNT5A reduced or blocked the amount of dye transferred between cells. In summary, we propose that WNT5A inhibits the response to oxytocin and prevents milk ejection through regulation of Cx43 function.
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Affiliation(s)
- Sarah E Baxley
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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17
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Abstract
Gap junctions (GJ) can no longer be thought of as simple channel forming structures that mediate intercellular communication. Hemi-channel and channel-independent functions of connexins (Cxs) have been described and numerous Cx interacting partners have been uncovered ranging from enzymes to structural and scaffolding molecules to transcription factors. With the growing number of Cx partners and functions, including well-documented roles for Cxs as conditional tumor suppressors, it has become essential to understand how Cxs are regulated in a context-dependent manner to mediate distinct functions. In this review we will shed light on the tissue and context-dependent regulation and function of Cxs and on the importance of Cx-interactions in modulating tissue-specific function. We will emphasize how the context-dependent functions of Cxs can help in understanding the impact of Cx mis-expression on cancer development and, ultimately, explore whether Cxs can be used as potential therapeutic targets in cancer treatment. In the end, we will address the need for developing relevant assays for studying Cx and GJ functions and will highlight how advances in bioengineering tools and the design of 3D biological platforms can help studying gap junction function in real time in a non-intrusive manner.
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Affiliation(s)
- R M Mroue
- Division of Life Sciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
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18
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Regulatory effects of myoendothelial gap junction on vascular reactivity after hemorrhagic shock in rats. Shock 2009; 31:80-6. [PMID: 19077877 DOI: 10.1097/shk.0b013e31817d3ef2-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Myoendothelial gap junction (MEGJ), one kind of gap junction between vascular endothelial cell and vascular smooth muscle cell, can transmit electrical and chemical signals to keep the electric and machinery activity synchronism of vasculature. After severe trauma or shock, vascular reactivity to vasoconstrictors or vasodilators is greatly reduced. However, whether MEGJ participates in the regulation of vascular reactivity after hemorrhagic shock, what type of MEGJ is involved, and what is the possible mechanism are unknown. With the hemorrhagic shock Sprague-Dawley rats and their superior mesenteric arteries (SMAs), the effects of 18alpha-glycyrrhetic acid, a lipophilic aglycone that disrupts gap junction plaques, on vascular contractile response to norepinephrine (endothelium-independent vascular constrictor), myricetin (endothelium-dependent vasoconstrictor) and relaxation reactivity to sodium nitroprusside (endothelium-independent vasodilator), and acetylcholine (Ach; endothelium-dependent vasodilator) were observed. Meanwhile, the relationship of the mRNA/protein expression of connexins 37, 40, and 43(Cx40 and Cx43) to the changes of vascular reactivity after hemorrhagic shock and the effect of antisense oligodeoxynucleotide of Cx40 or Cx43 on vascular calcium sensitivity and vascular reactivity were investigated. The results indicated that 18alpha-glycyrrhetic acid antagonized myricetin and Ach-induced SMA reactivity, but had no effect on norepinephrine- and sodium nitroprusside-induced vascular response. The mRNA and protein expression of Cx37 and Cx40 of SMA were negatively associated with the vascular reactivity, whereas Cx43 seemed to be a positive relationship to vascular reactivity. Antisense oligodeoxynucleotide of Cx40 significantly increased the calcium sensitivity, myricetin-induced vasoconstriction, and Ach-induced vasodilation, whereas antisense oligodeoxynucleotide of Cx43 depressed them. It was suggested that MEGJ plays an important role in the regulation of endothelium-dependent vascular reactivity after hemorrhagic shock. The involved types were mainly Cx40 and Cx43. The possible mechanism that Cx40/Cx43 regulates the endothelium-dependent vasoconstrictor reactivity may be related to their regulating effects on the calcium sensitivity of vascular smooth muscle cell.
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19
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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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20
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Conneely OM, Mulac-Jericevic B, Arnett-Mansfield R. Progesterone Signaling in Mammary Gland Development. PROGESTINS AND THE MAMMARY GLAND 2008. [DOI: 10.1007/2789_2008_075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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21
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McLachlan E, Shao Q, Laird DW. Connexins and gap junctions in mammary gland development and breast cancer progression. J Membr Biol 2007; 218:107-21. [PMID: 17661126 DOI: 10.1007/s00232-007-9052-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 05/14/2007] [Indexed: 01/19/2023]
Abstract
The development and function of the mammary gland require precise control of gap junctional intercellular communication (GJIC). Here, we review the expression and function of gap junction proteins, connexins, in the normal mouse and human mammary gland. We then discuss the possible tumor-suppressive role of Cx26 and Cx43 in primary breast tumors and through the various stages of breast cancer metastasis and consider whether connexins or GJIC may actually promote tumorigenesis at some stages. Finally, we present in vitro data on the impact of connexin expression on breast cancer cell metastasis to the bone. We observed that Cx43 expression inhibited the invasive and migratory potentials of MDA-MB-231 breast cancer cells in a bone microenvironment, provided by the MC3T3-E1 mouse osteoblastic cell line. Expression of either Cx26 or Cx43 had no effect on MDA-MB-231 growth and adhesion under the influence of osteoblasts and did not result in regulation of osteogenic gene expression in these breast cancer cells. Furthermore, connexin-expressing MDA-MB-231 cells did not have an effect on the growth or differentiation of MC3T3-E1 cells. In summary, we conclude that connexin expression and GJIC are integral to the development and differentiation of the mammary gland. In breast cancer, connexins generally act as tumor suppressors in the primary tumor; however, in advanced breast tumors, connexins appear to act as both context-dependent tumor suppressors and facilitators of disease progression.
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Affiliation(s)
- Elizabeth McLachlan
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
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22
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Rossiter H, Barresi C, Ghannadan M, Gruber F, Mildner M, Födinger D, Tschachler E. Inactivation of VEGF in mammary gland epithelium severely compromises mammary gland development and function. FASEB J 2007; 21:3994-4004. [PMID: 17625068 DOI: 10.1096/fj.07-8720com] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
To investigate the role of the angiogenic cytokine vascular endothelial growth factor (VEGF) during pregnancy and lactation, we used mice in which VEGF had been inactivated in mammary gland epithelial cells. Pups born to mutant mothers failed to thrive, displaying little milk in their stomachs. However, when they were transferred to control mothers they developed normally. Investigation of the mammary gland morphology revealed that lobulo-alveolar expansion into the fat pad was not complete in lactating mutant glands, and an accumulation of fat globules was evident in their secretory epithelium. In contrast to control glands, lactating mutant glands failed to up-regulate mRNAs for genes involved in milk secretion. Blood vessel density was comparable in pregnant mice of both groups but was only half that of controls in lactating mutant mice. FITC-labeled albumin injected intravenously (i.v.) into lactating mice extravasated rapidly and accumulated in the mammary gland epithelial cells in control animals, but was almost completely retained within the vessels in the mutants. Injection of recombinant VEGF i.v. reversed this effect. These findings demonstrate that mammary epithelium-derived VEGF is partially dispensable for angiogenesis during pregnancy and lactation, and by regulating vascular function during lactation, this factor is crucial to mammary gland differentiation and milk production.
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Affiliation(s)
- Heidemarie Rossiter
- Department of Dermatology, Medical University of Vienna, Waehringer GuerA-1090 Vienna, Austria
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23
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Miura D, Kida Y, Nojima H. Camellia oil and its distillate fractions effectively inhibit the spontaneous metastasis of mouse melanoma BL6 cells. FEBS Lett 2007; 581:2541-8. [PMID: 17499720 DOI: 10.1016/j.febslet.2007.04.080] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 04/15/2007] [Accepted: 04/25/2007] [Indexed: 01/02/2023]
Abstract
We previously reported that daily intraperitoneal injections of oleamide weakly inhibits the spontaneous metastasis of BL6 cells by blocking the gap junction-mediated intercellular communications (GJIC) of connexin 26 (Cx26). In the present study, we tested camellia oil, olive oil and cottonseed oil which are rich in oleamide-like oleic acid for their inhibitory potency on Cx26-mediated GJIC and spontaneous metastasis of BL6 cells. We found that camellia oil, olive oil and cottonseed oil, and their distillate fractions inhibited Cx26-mediated GJIC. We also showed that daily intraperitoneal injection of camellia oil and its distillate fractions more potently inhibited spontaneous lung metastasis of BL6 cells than oleamide. Moreover, a daily oral administration of camellia oil distillate fraction effectively inhibited spontaneous metastasis. Notably, even camellia Tempura-oil, a commercially available food, weakly inhibited the spontaneous metastasis of BL6 cells. Since these oils are used as foods and are quite safe, we propose that they could be used as supplements to protect patients from lung metastasis of melanomas.
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Affiliation(s)
- Daisaku Miura
- Biosafety Research Center for Foods, Drugs and Pesticides, Iwata, Shizuoka 437-1213, Japan
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24
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Locke D, Jamieson S, Stein T, Liu J, Hodgins MB, Harris AL, Gusterson B. Nature of Cx30-containing channels in the adult mouse mammary gland. Cell Tissue Res 2007; 328:97-107. [PMID: 17120054 DOI: 10.1007/s00441-006-0301-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 07/12/2006] [Indexed: 10/23/2022]
Abstract
Oligonucleotide microarray analysis uniquely shows that several members of the connexin family of gap junction proteins are expressed by the epithelium during mouse mammary gland development. Connexin 26 (Cx26) is present throughout pregnancy and lactation, is then undetectable shortly after weaning, but reappears during involution. Additionally, Cx30 is abundant in late-pregnant and early lactating gland epithelium. From mid-pregnancy into early lactation, Cx26 and Cx30 co-localize in junctional plaques between epithelial cells, forming hemichannels of mixed connexin content. Microarray analysis also shows Cx32 is developmentally restricted to parturition, suggesting that specific modification of gap junction channel composition and/or intercellular communication pathways occurs at parturition. Specifically, heteromeric channels of all pairwise combinations are formed when these connexins are expressed within the same cells. Of these hemichannels, Cx26/Cx32 pores are increasingly sensitive to closure by taurine (an osmolyte implicated in milk protein synthesis) with increasing Cx26 content. In contrast, physiological taurine concentrations have no effect on Cx26/Cx30 and Cx30/Cx32 channel activity. Such changes in connexin expression and channel composition and their chemical modulation are discussed in relation to the various stages of mammary gland development in the adult mouse.
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Affiliation(s)
- Darren Locke
- Department of Pharmacology and Physiology, New Jersey Medical School, UMDNJ, Newark, NJ 07103, USA.
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25
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Ott T, Jokwitz M, Lenhard D, Romualdi A, Dombrowski F, Ittrich C, Schwarz M, Willecke K. Ablation of gap junctional communication in hepatocytes of transgenic mice does not lead to disrupted cellular homeostasis or increased spontaneous tumourigenesis. Eur J Cell Biol 2006; 85:717-28. [PMID: 16740338 DOI: 10.1016/j.ejcb.2006.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 03/23/2006] [Accepted: 03/27/2006] [Indexed: 11/25/2022] Open
Abstract
Gap junctions between murine hepatocytes are composed of two subunit proteins, connexin26 (Cx26) and connexin32 (Cx32). Previously, we found increased formation of chemically induced liver tumours but no increase in spontaneous development of preneoplastic hepatic foci in mice that lacked Cx32 and expressed decreased amounts of Cx26. In order to clarify this tumour-suppressive effect and to overcome embryonic lethality of constitutive Cx26-deficient mice, cell type-specific targeting of the Cx26 gene was performed. Mice with loxP-flanked Cx26 coding DNA were crossed with mice expressing the Cre recombinase exclusively in hepatocytes. Progeny mice lacking Cx26 in the liver were viable and fertile with no obvious signs of phenotypic alterations. To generate mice that totally lack gap junctional intercellular coupling, these mice were crossed with constitutive Cx32-deficient mice. We found no increase in spontaneously induced liver tumour formation in Cx26 and double deficient Cx26/Cx32 mice. Occasionally, double deficient livers exhibited morphological alterations, like amyloidosis, and a slightly increased basal proliferation rate of hepatocytes. Although the absence of gap junction channels led to altered expression of adhesion-related proteins like E-cadherin and actin, microarray analyses of total liver transcripts yielded only few differences between Cx26-deficient and double deficient livers compared to control samples. Our results suggest that total lack of gap junctional communication due to hepatocytic ablation of Cx26 and Cx32 does not drastically alter basal hepatocytic function and does not lead to increased spontaneous liver tumour formation.
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Affiliation(s)
- Thomas Ott
- Institut für Genetik, Abteilung Molekulargenetik, Universität Bonn, Römerstr. 164, D-53117 Bonn, Germany
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26
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Lee NPY, Leung KW, Wo JY, Tam PC, Yeung WSB, Luk JM. Blockage of testicular connexins induced apoptosis in rat seminiferous epithelium. Apoptosis 2006; 11:1215-29. [PMID: 16699959 DOI: 10.1007/s10495-006-6981-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Spermatogenesis, a tightly regulated developmental process of male germ cells in testis, is associated with temporal and spatial expression of gap junction proteins, such as the connexin family members. Perturbation of their expressions may lead to spermatogenic arrest as manifested by disruption of cell-cell interaction. To explore the role(s) of connexins during spermatogenesis, we utilized the small peptide antagonistic approach to specifically deplete connexin 31, connexin 33, and pan-connexin. Three connexin peptides corresponding to the extracellular binding domain of connexin 31 and connexin 33 and to the extracellular conserved domain of connexins were designed and synthesized commercially. Peptides (at single dosage of 0.5, 1, or 2 mg per animal) were injected into rat testes and testes were collected on day 0, 1, 3, 5, 10, 15, and 30 after microinjection. In situ TUNEL assay demonstrated the induction of apoptosis in the testes after pan-connexin peptide treatment in a dose-dependent manner from day 3 and onward. Unlike the pan-connexin peptide, connexin 31 and connexin 33 peptides appeared to have little effect on inducing apoptosis and germ cell loss. CD45 staining also detected the occasional presence of infiltrating lymphocytes in the seminiferous tubules. Accompanied with the apoptotic events, two apoptotic markers, NF-kappaB and caspase 3, demonstrated a general up-regulation in their expressions. In adjacent testis sections, eliminations of connexin 31, 32, and 43 were observed. However, an induction of connexin 33 expression was detected. This suggests the versatility and functional diversity of connexins in the testis. The expression of ZO-1, the only known adaptor of connexins in the testis, was reduced and remained in a low level in the seminiferous epithelium. As such, the alterations of connexins in seminiferous epithelium may induce apoptotic signaling in the testis via the caspase 3 and the NF-kappaB pathway. This demonstrates the significant role of testicular connexins to maintain the survival of germ cells by regulating inter-cellular communications among germ cells and adjacent supporting cells during spermatogenesis. In addition, the inter-relationship between connexins and other junction proteins and associated signaling protein were investigated. After pan-connexin peptide treatment, a dys-localization of N-cadherin, an adherens junction protein, and diminution of occludin, a tight junction protein, level were detected. In addition, inductions of junction regulatory protein, cathepsin L, was observed during the course of peptide-mediated germ cell loss in the testes. In summary, pan-connexin peptide treatment triggered apoptosis and germ cell loss in the testes. This event influenced the localization and expression of different junction proteins and junction-associated protein in the testes.
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Affiliation(s)
- Nikki P Y Lee
- Departments of Surgery, The University of Hong Kong, L9-52 Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong
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27
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Zhao Y, Johansson C, Tran T, Bettencourt R, Itahana Y, Desprez PY, Konieczny SF. Identification of a basic helix-loop-helix transcription factor expressed in mammary gland alveolar cells and required for maintenance of the differentiated state. Mol Endocrinol 2006; 20:2187-98. [PMID: 16645041 DOI: 10.1210/me.2005-0214] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The development of mammary glands relies on complicated signaling pathways that control cell proliferation, differentiation, and apoptotic events through transcriptional regulatory circuits. A key family of transcription factors used in mammary gland development is the helix-loop-helix/basic helix-loop-helix (HLH/bHLH) protein family. In this study, we identify Mist1 as a tissue-restricted Class II bHLH transcription factor expressed in lactating mammary glands. Mouse and human mammary glands accumulated Mist1 protein exclusively in secretory alveolar cells, and Mist1 transcripts were differentially expressed in mouse SCp2 cells induced to differentiate by addition of lactogenic hormones. Mist1 null (Mist1(KO)) lactating mammary glands were defective in normal lobuloalveolar organization, exhibiting shedding of cells into the alveolus lumen and premature activation of the signal transducer and activator of transcription 3 signaling pathway. These cells also failed to maintain expression of the gap junction proteins connexin26 and connexin32, leading to the loss of gap junctions. Our findings suggest that loss of Mist1 impairs the maintenance of the fully differentiated alveolar state and, for the first time, places Mist1 within the hierarchy of known HLH/bHLH proteins that control mammary epithelial cell development.
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Affiliation(s)
- Yan Zhao
- Department of Biological Sciences and the Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907-2064, USA
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Oakes SR, Hilton HN, Ormandy CJ. The alveolar switch: coordinating the proliferative cues and cell fate decisions that drive the formation of lobuloalveoli from ductal epithelium. Breast Cancer Res 2006; 8:207. [PMID: 16677418 PMCID: PMC1557712 DOI: 10.1186/bcr1411] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Massive tissue remodelling occurs within the mammary gland during pregnancy, resulting in the formation of lobuloalveoli that are capable of milk secretion. Endocrine signals generated predominantly by prolactin and progesterone operate the alveolar switch to initiate these developmental events. Here we review the current understanding of the components of the alveolar switch and conclude with an examination of the role of the ets transcription factor Elf5. We propose that Elf5 is a key regulator of the alveolar switch.
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Affiliation(s)
- Samantha R Oakes
- Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW 2010, Australia
| | - Heidi N Hilton
- Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW 2010, Australia
| | - Christopher J Ormandy
- Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW 2010, Australia
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Shimizu K, Shimoichi Y, Hinotsume D, Itsuzaki Y, Fujii H, Honoki K, Tsujiuchi T. Reduced expression of the Connexin26 gene and its aberrant DNA methylation in rat lung adenocarcinomas induced by N-nitrosobis(2-Hydroxypropyl)amine. Mol Carcinog 2006; 45:710-4. [PMID: 16637067 DOI: 10.1002/mc.20207] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Gap junctions are mediated by intercellular channels that connect adjacent cells and are composed of Connexin (Cx) proteins. A member of the Cx family, Cx26 is considered a potential tumor suppressor in several cancers. The expression of Cx26 gene and its methylation status in rat lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) were investigated. Six-wk-old male Wistar rats were given 2,000 ppm BHP in their drinking water for 12 wk and maintained without further treatment until they were sacrificed at 25 wk. A total of nine lung adenocarcinomas were obtained and total RNA was extracted to assess expression by real-time quantitative reverse transcription (RT)-polymerase chain reaction (PCR). Five out of nine adenocarcinomas showed reduced expression compared with normal lung tissue. We next performed a bisulfite sequence analysis to measure the methylation status of the 5' upstream region of the Cx26 gene in two normal lung tissues and five lung adenocarcinomas that showed reduced expression of Cx26. All five adenocarcinomas were highly methylated in the 5' upstream region, while the two normal lung tissues were unmethylated. This suggests that aberrant methylation of the Cx26 gene may be involved in the development of lung adenocarcinomas induced by BHP in rats.
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Affiliation(s)
- Kyoko Shimizu
- Laboratory of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, Higashiosaka, Osaka, Japan
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30
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Michon L, Nlend Nlend R, Bavamian S, Bischoff L, Boucard N, Caille D, Cancela J, Charollais A, Charpantier E, Klee P, Peyrou M, Populaire C, Zulianello L, Meda P. Involvement of gap junctional communication in secretion. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1719:82-101. [PMID: 16359942 DOI: 10.1016/j.bbamem.2005.11.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 10/31/2005] [Accepted: 11/07/2005] [Indexed: 11/26/2022]
Abstract
Glands were the first type of tissues in which the permissive role of gap junctions in the cell-to-cell transfer of membrane-impermeant molecules was shown. During the 40 years that have followed this seminal finding, gap junctions have been documented in all types of multicellular secretory systems, whether of the exocrine, endocrine or pheromonal nature. Also, compelling evidence now indicates that gap junction-mediated coupling, and/or the connexin proteins per se, play significant regulatory roles in various aspects of gland functions, ranging from the biosynthesis, storage and release of a variety of secretory products, to the control of the growth and differentiation of secretory cells, and to the regulation of gland morphogenesis. This review summarizes this evidence in the light of recent reports.
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Affiliation(s)
- Laetitia Michon
- Department of Cell Physiology and Metabolism, University of Geneva, C.M.U., 1 rue Michel Servet, 1211 Geneva 4, Switzerland
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31
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Abstract
Unique developmental features during puberty, pregnancy, lactation and post-lactation make the mammary gland a prime object to explore genetic circuits that control the specification, proliferation, differentiation, survival and death of cells. Steroids and simple peptide hormones initiate and carry out complex developmental programmes, and reverse genetics has been used to define the underlying mechanistic connections.
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Affiliation(s)
- Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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32
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Chen Y, Hühn D, Knösel T, Pacyna-Gengelbach M, Deutschmann N, Petersen I. Downregulation of connexin 26 in human lung cancer is related to promoter methylation. Int J Cancer 2004; 113:14-21. [PMID: 15386363 DOI: 10.1002/ijc.20498] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cell-Cell communication via gap junctions plays a key role in carcinogenesis and in growth control. One of the gap junction proteins, Connexin 26 (Cx26) was considered as tumor suppressor in various cancers. In our study, the expression of Cx26 was analyzed in human lung cancer. The reduced mRNA expression was observed in 17 lung cancer cell lines examined by Northern blot analysis and RT-PCR. In 138 primary carcinomas comprising all subtypes analyzed by immunohistochemistry, 85 cases (62%) exhibited no expression of Cx26, whereas in other 53 cases the Cx26 staining was positive (38%). Additionally, an association between Cx26 protein expression and higher grading of tumors was found in whole tumor samples (p =0.028) but no statistically significant correlations could be observed with tumor stage, tumor size and node status. In squamous cell carcinoma, tumors with higher stage and grading were linked to higher expression of Cx26 (p = 0.015 and 0.017, respectively). To explore the mechanism responsible for the downregulation of Cx26, we treated 2 lung cancer cell lines H2170 and H226 with the demethylation agent 5-aza-2'-deoxycytidine and found the reexpression of Cx26 mRNA. Methylation status of these 2 cell lines was further analyzed by PCR amplification of bisulfite modified DNA and sequencing. A heterogeneous methylation pattern turned out. Our results suggest the inactivation of Cx26 in lung cancer may be explained by promoter methylation.
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MESH Headings
- Actins
- Antimetabolites, Antineoplastic/pharmacology
- Azacitidine/analogs & derivatives
- Azacitidine/pharmacology
- Blotting, Northern
- Blotting, Southern
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/pathology
- Cell Line, Tumor
- Connexin 26
- Connexins/genetics
- DNA Methylation/drug effects
- DNA Modification Methylases/antagonists & inhibitors
- DNA, Neoplasm/metabolism
- Decitabine
- Down-Regulation/drug effects
- Enzyme Inhibitors/pharmacology
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Neoplastic/drug effects
- Glyceraldehyde-3-Phosphate Dehydrogenases
- Humans
- Immunohistochemistry
- Lung Neoplasms/drug therapy
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Promoter Regions, Genetic/drug effects
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
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Affiliation(s)
- Yuan Chen
- Institute of Pathology, University Hospital Charité, Berlin, Germany
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33
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Locke D, Stein T, Davies C, Morris J, Harris AL, Evans WH, Monaghan P, Gusterson B. Altered permeability and modulatory character of connexin channels during mammary gland development. Exp Cell Res 2004; 298:643-60. [PMID: 15265710 DOI: 10.1016/j.yexcr.2004.05.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Revised: 05/10/2004] [Indexed: 10/26/2022]
Abstract
Abrupt developmental changes occur in structural form and function of connexin (Cx) channels in the mouse mammary gland. Microarray study shows that the principal connexin isoform in epithelial cells during pregnancy is Cx26, up-regulated and persisting from the virgin. After parturition, there is rapid induction of Cx32. In epithelial plasma membranes, size exclusion chromatography reveals that Cx32 organizes initially with Cx26 as heteromeric (Cx26-Cx32) hemichannels and later in heteromeric and homomeric Cx32 channels. Dramatic alterations of connexin channel function following these developmental changes in channel composition are characterized using native channels reconstituted into liposomes. Changes to channel stoichiometry increase the allowable physical size limits of permeant after parturition; the new Cx32 channels are wider than channels containing Cx26. Most remarkably, heteromeric Cx26-Cx32 channels are selectively permeability to adenosine 3',5' cyclic phosphate (cAMP), guanosine 3',5' cyclic phosphate (cGMP), and inositol 1,4,5-triphosphate (IP(3)), whereas homomeric channels are not. Homomeric Cx26 and heteromeric channels with high Cx26/Cx32 stoichiometry are also inhibited by taurine, an osmolyte playing a key role in milk protein synthesis. Taurine effect is reduced where heteromeric channels contain Cx32 > Cx26 and eliminated when channels contain only Cx32. Connexin channel stoichiometry, permeability, and chemical gating character change in precisely the desired fashion after parturition to maximize molecular and electrical coupling to support coordinated milk secretion.
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Affiliation(s)
- Darren Locke
- Department of Pharmacology and Physiology, UMDNJ, Newark, NJ 07101, USA.
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