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Wicker MN, Wagner KU. Cellular Plasticity in Mammary Gland Development and Breast Cancer. Cancers (Basel) 2023; 15:5605. [PMID: 38067308 PMCID: PMC10705338 DOI: 10.3390/cancers15235605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/17/2023] [Accepted: 11/23/2023] [Indexed: 02/12/2024] Open
Abstract
Cellular plasticity is a phenomenon where cells adopt different identities during development and tissue homeostasis as a response to physiological and pathological conditions. This review provides a general introduction to processes by which cells change their identity as well as the current definition of cellular plasticity in the field of mammary gland biology. Following a synopsis of the evolving model of the hierarchical development of mammary epithelial cell lineages, we discuss changes in cell identity during normal mammary gland development with particular emphasis on the effect of the gestation cycle on the emergence of new cellular states. Next, we summarize known mechanisms that promote the plasticity of epithelial lineages in the normal mammary gland and highlight the importance of the microenvironment and extracellular matrix. A discourse of cellular reprogramming during the early stages of mammary tumorigenesis that follows focuses on the origin of basal-like breast cancers from luminal progenitors and oncogenic signaling networks that orchestrate diverse developmental trajectories of transforming epithelial cells. In addition to the epithelial-to-mesenchymal transition, we highlight events of cellular reprogramming during breast cancer progression in the context of intrinsic molecular subtype switching and the genesis of the claudin-low breast cancer subtype, which represents the far end of the spectrum of epithelial cell plasticity. In the final section, we will discuss recent advances in the design of genetically engineered models to gain insight into the dynamic processes that promote cellular plasticity during mammary gland development and tumorigenesis in vivo.
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Affiliation(s)
| | - Kay-Uwe Wagner
- Department of Oncology, Wayne State University School of Medicine and Tumor Biology Program, Barbara Ann Karmanos Cancer Institute, 4100 John R, EL01TM, Detroit, MI 48201, USA
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2
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Bruns M, Wanger J, Utermöhlen O, Deppert W. An inducible transgenic mouse breast cancer model for the analysis of tumor antigen specific CD8+ T-cell responses. Oncotarget 2016; 6:38487-503. [PMID: 26513294 PMCID: PMC4770716 DOI: 10.18632/oncotarget.5750] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/06/2015] [Indexed: 02/06/2023] Open
Abstract
In Simian virus 40 (SV40) transgenic BALB/c WAP-T mice tumor development and progression is driven by SV40 tumor antigens encoded by inducible transgenes. WAP-T mice constitute a well characterized mouse model for breast cancer with strong similarities to the corresponding human disease. BALB/c mice mount only a weak cellular immune response against SV40 T-antigen (T-Ag). For studying tumor antigen specific CD8+ T-cell responses against transgene expressing cells, we created WAP-TNP mice, in which the transgene additionally codes for the NP118–126-epitope contained within the nucleoprotein of lymphocytic choriomeningitis virus (LCMV), the immune-dominant T-cell epitope in BALB/c mice. We then investigated in WAP-TNP mice the immune responses against SV40 tumor antigens and the NP-epitope within the chimeric T-Ag/NP protein (T-AgNP). Analysis of the immune-reactivity against T-Ag in WAP-T and of T-AgNP in WAP-TNP mice revealed that, in contrast to wild type (wt) BALB/c mice, WAP-T and WAP-TNP mice were non-reactive against T-Ag. However, like wtBALB/c mice, WAP-T as well as WAP-TNP mice were highly reactive against the immune-dominant LCMV NP-epitope, thereby allowing the analysis of NP-epitope specific cellular immune responses in WAP-TNP mice. LCMV infection of WAP-TNP mice induced a strong, LCMV NP-epitope specific CD8+ T-cell response, which was able to specifically eliminate T-AgNP expressing mammary epithelial cells both prior to tumor formation (i.e. in cells of lactating mammary glands), as well as in invasive tumors. Elimination of tumor cells, however, was only transient, even after repeated LCMV infections. Further studies showed that already non-infected WAP-TNP tumor mice contained LCMV NP-epitope specific CD8+ T-cells, albeit with strongly reduced, though measurable activity. Functional impairment of these ‘endogenous’ NP-epitope specific T-cells seems to be caused by expression of the programmed death-1 protein (PD1), as anti-PD1 treatment of splenocytes from WAP-TNP tumor mice restored their activity. These characteristics are similar to those found in many tumor patients and render WAP-TNP mice a suitable model for analyzing parameters to overcome the blockade of immune checkpoints in tumor patients.
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Affiliation(s)
- Michael Bruns
- Heinrich-Pette-Institute, Leibniz-Institute for Experimental Virology, Hamburg, Germany
| | - Jara Wanger
- Heinrich-Pette-Institute, Leibniz-Institute for Experimental Virology, Hamburg, Germany
| | - Olaf Utermöhlen
- Institute for Medical Microbiology, Immunology and Hygiene, Medical Center and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Wolfgang Deppert
- Heinrich-Pette-Institute, Leibniz-Institute for Experimental Virology, Hamburg, Germany.,Institute for Tumor Biology, University Medical Center Hamburg-Eppendorf (UKE), University of Hamburg, Hamburg, Germany
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3
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Willi M, Yoo KH, Wang C, Trajanoski Z, Hennighausen L. Differential cytokine sensitivities of STAT5-dependent enhancers rely on Stat5 autoregulation. Nucleic Acids Res 2016; 44:10277-10291. [PMID: 27694626 PMCID: PMC5137441 DOI: 10.1093/nar/gkw844] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/22/2016] [Accepted: 09/11/2016] [Indexed: 12/28/2022] Open
Abstract
Cytokines utilize the transcription factor STAT5 to control cell-specific genes at a larger scale than universal genes, with a mechanistic explanation yet to be supplied. Genome-wide studies have identified putative STAT5-based mammary-specific and universal enhancers, an opportunity to investigate mechanisms underlying their differential response to cytokines. We have now interrogated the integrity and function of both categories of regulatory elements using biological and genetic approaches. During lactation, STAT5 occupies mammary-specific and universal cytokine-responsive elements. Following lactation, prolactin levels decline and mammary-specific STAT5-dependent enhancers are decommissioned within 24 h, while universal regulatory complexes remain intact. These differential sensitivities are linked to STAT5 concentrations and the mammary-specific Stat5 autoregulatory enhancer. In its absence, mammary-specific enhancers, but not universal elements, fail to be fully established. Upon termination of lactation STAT5 binding to a subset of mammary enhancers is substituted by STAT3. No STAT3 binding was observed at the most sensitive STAT5 enhancers suggesting that upon hormone withdrawal their chromatin becomes inaccessible. Lastly, we demonstrate that the mammary-enriched transcription factors GR, ELF5 and NFIB associate with STAT5 at sites lacking bona fide binding motifs. This study provides, for the first time, molecular insight into the differential sensitivities of mammary-specific and universal cytokine-sensing enhancers.
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Affiliation(s)
- Michaela Willi
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA.,Division of Bioinformatics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Kyung Hyun Yoo
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA.,Department of Life Systems, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Chaochen Wang
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA
| | - Zlatko Trajanoski
- Division of Bioinformatics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health, Bethesda, MD 20892, USA
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4
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Hierarchy within the mammary STAT5-driven Wap super-enhancer. Nat Genet 2016; 48:904-911. [PMID: 27376239 PMCID: PMC4963296 DOI: 10.1038/ng.3606] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/03/2016] [Indexed: 12/14/2022]
Abstract
Super-enhancers comprise of dense transcription factor platforms highly enriched for active chromatin marks. A paucity of functional data led us to investigate their role in the mammary gland, an organ characterized by exceptional gene regulatory dynamics during pregnancy. ChIP-Seq for the master regulator STAT5, the glucocorticoid receptor, H3K27ac and MED1, identified 440 mammary-specific super-enhancers, half of which were associated with genes activated during pregnancy. We interrogated the Wap super-enhancer, generating mice carrying mutations in STAT5 binding sites within its three constituent enhancers. Individually, only the most distal site displayed significant enhancer activity. However, combinatorial mutations showed that the 1,000-fold gene induction relied on all enhancers. Disabling the binding sites of STAT5, NFIB and ELF5 in the proximal enhancer incapacitated the entire super-enhancer, suggesting an enhancer hierarchy. The identification of mammary-specific super-enhancers and the mechanistic exploration of the Wap locus provide insight into the complexity of cell-specific and hormone-regulated genes.
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Zhao J, Xu W, Ross JW, Walters EM, Butler SP, Whyte JJ, Kelso L, Fatemi M, Vanderslice NC, Giroux K, Spate LD, Samuel MS, Murphy CN, Wells KD, Masiello NC, Prather RS, Velander WH. Engineering protein processing of the mammary gland to produce abundant hemophilia B therapy in milk. Sci Rep 2015; 5:14176. [PMID: 26387706 PMCID: PMC4585688 DOI: 10.1038/srep14176] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 07/22/2015] [Indexed: 11/20/2022] Open
Abstract
Both the low animal cell density of bioreactors and their ability to post-translationally process recombinant factor IX (rFIX) limit hemophilia B therapy to <20% of the world’s population. We used transgenic pigs to make rFIX in milk at about 3,000-fold higher output than provided by industrial bioreactors. However, this resulted in incomplete γ-carboxylation and propeptide cleavage where both processes are transmembrane mediated. We then bioengineered the co-expression of truncated, soluble human furin (rFurin) with pro-rFIX at a favorable enzyme to substrate ratio. This resulted in the complete conversion of pro-rFIX to rFIX while yielding a normal lactation. Importantly, these high levels of propeptide processing by soluble rFurin did not preempt γ-carboxylation in the ER and therefore was compartmentalized to the Trans-Golgi Network (TGN) and also to milk. The Golgi specific engineering demonstrated here segues the ER targeted enhancement of γ-carboxylation needed to biomanufacture coagulation proteins like rFIX using transgenic livestock.
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Affiliation(s)
- Jianguo Zhao
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA.,State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China, 100101
| | - Weijie Xu
- Protein Purification and Characterization Laboratories, Department of Chemical and Biomolecular Engineering, 207 Othmer Hall, University of Nebraska, Lincoln 68588, USA
| | - Jason W Ross
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA.,Department of Animal Science, Iowa State University, Ames, IA 50011, USA
| | - Eric M Walters
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | | | - Jeff J Whyte
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - Lindsey Kelso
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - Mostafa Fatemi
- Protein Purification and Characterization Laboratories, Department of Chemical and Biomolecular Engineering, 207 Othmer Hall, University of Nebraska, Lincoln 68588, USA
| | - Nicholas C Vanderslice
- Protein Purification and Characterization Laboratories, Department of Chemical and Biomolecular Engineering, 207 Othmer Hall, University of Nebraska, Lincoln 68588, USA
| | - Keith Giroux
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - Lee D Spate
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - Melissa S Samuel
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - Cliff N Murphy
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - Kevin D Wells
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | | | - Randall S Prather
- National Swine Resource and Research Center &Division of Animal Science, University of Missouri, Columbia, MO 65211, USA
| | - William H Velander
- Protein Purification and Characterization Laboratories, Department of Chemical and Biomolecular Engineering, 207 Othmer Hall, University of Nebraska, Lincoln 68588, USA
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Chang THT, Kunasegaran K, Tarulli GA, De Silva D, Voorhoeve PM, Pietersen AM. New insights into lineage restriction of mammary gland epithelium using parity-identified mammary epithelial cells. Breast Cancer Res 2014; 16:R1. [PMID: 24398145 PMCID: PMC3978646 DOI: 10.1186/bcr3593] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/10/2013] [Indexed: 12/21/2022] Open
Abstract
Introduction Parity-identified mammary epithelial cells (PI-MECs) are an interesting cellular subset because they survive involution and are a presumptive target for transformation by human epidermal growth factor receptor 2 (HER2)/neu in mammary tumors. Depending on the type of assay, PI-MECs have been designated lobule-restricted progenitors or multipotent stem/progenitor cells. PI-MECs were reported to be part of the basal population of mammary epithelium based on flow cytometry. We investigated the cellular identity and lineage potential of PI-MECs in intact mammary glands. Methods We performed a quantitative and qualitative analysis of the contribution of PI-MECs to mammary epithelial cell lineages in pregnant and involuted mammary glands by immunohistochemistry, fluorescence-activated cells sorting (FACS), and quantitative polymerase chain reaction. PI-MECs were labeled by the activation of Whey Acidic Protein (WAP)-Cre during pregnancy that results in permanent expression of yellow fluorescent protein. Results After involution, PI-MECs are present exclusively in the luminal layer of mammary ducts. During pregnancy, PI-MECs contribute to the luminal layer but not the basal layer of alveolar lobules. Strikingly, whereas all luminal estrogen receptor (ER)-negative cells in an alveolus can be derived from PI-MECs, the alveolar ER-positive cells are unlabeled and reminiscent of Notch2-traced L cells. Notably, we observed a significant population of unlabeled alveolar progenitors that resemble PI-MECs based on transcriptional and histological analysis. Conclusions Our demonstration that PI-MECs are luminal cells underscores that not only basal cells display multi-lineage potential in transplantation assays. However, the lineage potential of PI-MECs in unperturbed mammary glands is remarkably restricted to luminal ER-negative cells of the secretory alveolar lineage. The identification of an unlabeled but functionally similar population of luminal alveolar progenitor cells raises the question of whether PI-MECs are a unique population or the result of stochastic labeling. Interestingly, even when all luminal ER-negative cells of an alveolus are PI-MEC-derived, the basal cells and hormone-sensing cells are derived from a different source, indicating that cooperative outgrowth of cells from different lineages is common in alveologenesis.
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The tammar wallaby: a model system to examine domain-specific delivery of milk protein bioactives. Semin Cell Dev Biol 2012; 23:547-56. [PMID: 22498725 DOI: 10.1016/j.semcdb.2012.03.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 11/23/2022]
Abstract
The role of milk extends beyond simply providing nutrition to the suckled young. Milk has a comprehensive role in programming and regulating growth and development of the suckled young, and provides a number of potential autocrine factors so that the mammary gland functions appropriately during the lactation cycle. This central role of milk is best studied in animal models such as marsupials that have evolved a different lactation strategy to eutherians and allow researchers to more easily identify regulatory mechanisms that are not as readily apparent in eutherian species. For example, the tammar wallaby (Macropus eugenii) has evolved with a unique reproductive strategy of a short gestation, birth of an altricial young and a relatively long lactation during which the mother progressively changes the composition of the major, and many of the minor components of milk. Consequently, in contrast to eutherians, there is a far greater investment in development of the young during lactation and it is likely that many of the signals that regulate development of eutherian embryos in utero are delivered by the milk. This requires the co-ordinated development and function of the mammary gland since inappropriate timing of these signalling events may result in either limited or abnormal development of the young, and potentially a higher incidence of mature onset disease. Milk proteins play a significant role in these processes by providing timely presentation of signalling molecules and antibacterial protection for the young and the mammary gland at times when there is increased susceptibility to infection. This review describes studies exploiting the unique reproductive strategy of the tammar wallaby to investigate the role of several proteins secreted at specific times during the lactation cycle and that are correlated with potential roles in the young and mammary gland. Interestingly, alternative splicing of some milk protein genes has been utilised by the mammary gland to deliver domain-specific functions at specific times during lactation.
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8
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Serber DW, Rogala A, Makarem M, Rosson GB, Simin K, Godfrey V, Van Dyke T, Eaves CJ, Bultman SJ. The BRG1 chromatin remodeler protects against ovarian cysts, uterine tumors, and mammary tumors in a lineage-specific manner. PLoS One 2012; 7:e31346. [PMID: 22363625 PMCID: PMC3283619 DOI: 10.1371/journal.pone.0031346] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 01/06/2012] [Indexed: 12/27/2022] Open
Abstract
The BRG1 catalytic subunit of SWI/SNF-related complexes is required for mammalian development as exemplified by the early embryonic lethality of Brg1 null homozygous mice. BRG1 is also a tumor suppressor and, in mice, 10% of heterozygous (Brg1(null/+)) females develop mammary tumors. We now demonstrate that BRG1 mRNA and protein are expressed in both the luminal and basal cells of the mammary gland, raising the question of which lineage requires BRG1 to promote mammary homeostasis and prevent oncogenic transformation. To investigate this question, we utilized Wap-Cre to mutate both Brg1 floxed alleles in the luminal cells of the mammary epithelium of pregnant mice where WAP is exclusively expressed within the mammary gland. Interestingly, we found that Brg1(Wap-Cre) conditional homozygotes lactated normally and did not develop mammary tumors even when they were maintained on a Brm-deficient background. However, Brg1(Wap-Cre) mutants did develop ovarian cysts and uterine tumors. Analysis of these latter tissues showed that both, like the mammary gland, contain cells that normally express Brg1 and Wap. Thus, tumor formation in Brg1 mutant mice appears to be confined to particular cell types that require BRG1 and also express Wap. Our results now show that such cells exist both in the ovary and the uterus but not in either the luminal or the basal compartments of the mammary gland. Taken together, these findings indicate that SWI/SNF-related complexes are dispensable in the luminal cells of the mammary gland and therefore argue against the notion that SWI/SNF-related complexes are essential for cell survival. These findings also suggest that the tumor-suppressor activity of BRG1 is restricted to the basal cells of the mammary gland and demonstrate that this function extends to other female reproductive organs, consistent with recent observations of recurrent ARID1A/BAF250a mutations in human ovarian and endometrial tumors.
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Affiliation(s)
- Daniel W. Serber
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Allison Rogala
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Maisam Makarem
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gary B. Rosson
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Karl Simin
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Virginia Godfrey
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Terry Van Dyke
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Connie J. Eaves
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Scott J. Bultman
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
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Hirner H, Günes C, Bischof J, Wolff S, Grothey A, Kühl M, Oswald F, Wegwitz F, Bösl MR, Trauzold A, Henne-Bruns D, Peifer C, Leithäuser F, Deppert W, Knippschild U. Impaired CK1 delta activity attenuates SV40-induced cellular transformation in vitro and mouse mammary carcinogenesis in vivo. PLoS One 2012; 7:e29709. [PMID: 22235331 PMCID: PMC3250488 DOI: 10.1371/journal.pone.0029709] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 12/01/2011] [Indexed: 02/05/2023] Open
Abstract
Simian virus 40 (SV40) is a powerful tool to study cellular transformation in vitro, as well as tumor development and progression in vivo. Various cellular kinases, among them members of the CK1 family, play an important role in modulating the transforming activity of SV40, including the transforming activity of T-Ag, the major transforming protein of SV40, itself. Here we characterized the effects of mutant CK1δ variants with impaired kinase activity on SV40-induced cell transformation in vitro, and on SV40-induced mammary carcinogenesis in vivo in a transgenic/bi-transgenic mouse model. CK1δ mutants exhibited a reduced kinase activity compared to wtCK1δ in in vitro kinase assays. Molecular modeling studies suggested that mutation N172D, located within the substrate binding region, is mainly responsible for impaired mutCK1δ activity. When stably over-expressed in maximal transformed SV-52 cells, CK1δ mutants induced reversion to a minimal transformed phenotype by dominant-negative interference with endogenous wtCK1δ. To characterize the effects of CK1δ on SV40-induced mammary carcinogenesis, we generated transgenic mice expressing mutant CK1δ under the control of the whey acidic protein (WAP) gene promoter, and crossed them with SV40 transgenic WAP-T-antigen (WAP-T) mice. Both WAP-T mice as well as WAP-mutCK1δ/WAP-T bi-transgenic mice developed breast cancer. However, tumor incidence was lower and life span was significantly longer in WAP-mutCK1δ/WAP-T bi-transgenic animals. The reduced CK1δ activity did not affect early lesion formation during tumorigenesis, suggesting that impaired CK1δ activity reduces the probability for outgrowth of in situ carcinomas to invasive carcinomas. The different tumorigenic potential of SV40 in WAP-T and WAP-mutCK1δ/WAP-T tumors was also reflected by a significantly different expression of various genes known to be involved in tumor progression, specifically of those involved in wnt-signaling and DNA repair. Our data show that inactivating mutations in CK1δ impair SV40-induced cellular transformation in vitro and mouse mammary carcinogenesis in vivo.
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MESH Headings
- Animals
- Antigens, Viral, Tumor/immunology
- Casein Kinase Idelta/chemistry
- Casein Kinase Idelta/genetics
- Casein Kinase Idelta/metabolism
- Cell Line
- Cell Line, Tumor
- Cell Transformation, Viral/genetics
- Disease Progression
- Female
- Gene Expression Regulation
- Male
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Glands, Animal/virology
- Mammary Neoplasms, Experimental/enzymology
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/pathology
- Mammary Neoplasms, Experimental/virology
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Milk Proteins/genetics
- Models, Molecular
- Mutation
- Phenotype
- Phosphorylation
- Promoter Regions, Genetic/genetics
- Protein Structure, Tertiary
- Simian virus 40/immunology
- Simian virus 40/physiology
- Survival Analysis
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Affiliation(s)
- Heidrun Hirner
- Department of General-, Visceral- and Transplantation Surgery, University of Ulm, Ulm, Germany
| | - Cagatay Günes
- Institute of Molecular Medicine and Max-Planck-Research Group on Stem Cell Aging, University of Ulm, Ulm, Germany
| | - Joachim Bischof
- Department of General-, Visceral- and Transplantation Surgery, University of Ulm, Ulm, Germany
| | - Sonja Wolff
- Department of General-, Visceral- and Transplantation Surgery, University of Ulm, Ulm, Germany
| | - Arnhild Grothey
- Department of General-, Visceral- and Transplantation Surgery, University of Ulm, Ulm, Germany
| | - Marion Kühl
- Department of Tumor Virology, Heinrich-Pette-Institute, Leibniz-Center for Experimental Virology, Hamburg, Germany
| | - Franz Oswald
- Department of Internal Medicine I, University of Ulm, Ulm, Germany
| | - Florian Wegwitz
- Department of Tumor Virology, Heinrich-Pette-Institute, Leibniz-Center for Experimental Virology, Hamburg, Germany
| | - Michael R. Bösl
- Max Planck Institute of Neurobiology Transgenic Mouse Models, Max Planck Institute, Martinsried, Germany
| | - Anna Trauzold
- Division of Molecular Oncology, Institute for Experimental Cancer Research, CCCNorth, UK S-H, Kiel, Germany
| | - Doris Henne-Bruns
- Department of General-, Visceral- and Transplantation Surgery, University of Ulm, Ulm, Germany
| | | | | | - Wolfgang Deppert
- Department of Tumor Virology, Heinrich-Pette-Institute, Leibniz-Center for Experimental Virology, Hamburg, Germany
| | - Uwe Knippschild
- Department of General-, Visceral- and Transplantation Surgery, University of Ulm, Ulm, Germany
- * E-mail:
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Park S, Zhao Y, Yoon S, Xu J, Liao L, Lydon J, DeMayo F, O'Malley BW, Katzenellenbogen BS. Repressor of estrogen receptor activity (REA) is essential for mammary gland morphogenesis and functional activities: studies in conditional knockout mice. Endocrinology 2011; 152:4336-49. [PMID: 21862609 PMCID: PMC3199013 DOI: 10.1210/en.2011-1100] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Estrogen receptor (ER) is a key regulator of mammary gland development and is also implicated in breast tumorigenesis. Because ER-mediated activities depend critically on coregulator partner proteins, we have investigated the consequences of reduction or loss of function of the coregulator repressor of ER activity (REA) by conditionally deleting one allele or both alleles of the REA gene at different stages of mammary gland development. Notably, we find that heterozygosity and nullizygosity for REA result in very different mammary phenotypes and that REA has essential roles in the distinct morphogenesis and functions of the mammary gland at different stages of development, pregnancy, and lactation. During puberty, mice homozygous null for REA in the mammary gland (REAf/f PRcre/+) showed severely impaired mammary ductal elongation and morphogenesis, whereas mice heterozygous for REA (REAf/+ PRcre/+) displayed accelerated mammary ductal elongation, increased numbers of terminal end buds, and up-regulation of amphiregulin, the major paracrine mediator of estrogen-induced ductal morphogenesis. During pregnancy and lactation, mice with homozygous REA gene deletion in mammary epithelium (REAf/f whey acidic protein-Cre) showed a loss of lobuloalveolar structures and increased apoptosis of mammary alveolar epithelium, leading to impaired milk production and significant reduction in growth of their offspring, whereas body weights of the offspring nursed by females heterozygous for REA were slightly greater than those of control mice. Our findings reveal that REA is essential for mammary gland development and has a gene dosage-dependent role in the regulation of stage-specific physiological functions of the mammary gland.
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Affiliation(s)
- Sunghee Park
- Department of Molecular and Integrative Physiology, University of Illinois, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois 61801-3704, USA
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Sun Z, Shushanov S, LeRoith D, Wood TL. Decreased IGF type 1 receptor signaling in mammary epithelium during pregnancy leads to reduced proliferation, alveolar differentiation, and expression of insulin receptor substrate (IRS)-1 and IRS-2. Endocrinology 2011; 152:3233-45. [PMID: 21628386 PMCID: PMC3138223 DOI: 10.1210/en.2010-1296] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The IGFs and the IGF type 1 receptor (IGF-1R) are essential mediators of normal mammary gland development in mice. IGF-I and the IGF-1R have demonstrated functions in formation and proliferation of terminal end buds and in ductal outgrowth and branching during puberty. To study the functions of IGF-1R during pregnancy and lactation, we established transgenic mouse lines expressing a human dominant-negative kinase dead IGF-1R (dnhIGF-1R) under the control of the whey acidic protein promoter. We provide evidence that the IGF-1R pathway is necessary for normal epithelial proliferation and alveolar formation during pregnancy. Furthermore, we demonstrate that the whey acidic protein-dnhIGF-1R transgene causes a delay in alveolar differentiation including lipid droplet formation, lumen expansion, and β-casein protein expression. Analysis of IGF-1R signaling pathways showed a decrease in P-IGF-1R and P-Akt resulting from expression of the dnhIGF-1R. We further demonstrate that disruption of the IGF-1R decreases mammary epithelial cell expression of the signaling intermediates insulin receptor substrate (IRS)-1 and IRS-2. No alterations were observed in downstream signaling targets of prolactin and progesterone, suggesting that activation of the IGF-1R may directly regulate expression of IRS-1/2 during alveolar development and differentiation. These data show that IGF-1R signaling is necessary for normal alveolar proliferation and differentiation, in part, through induction of signaling intermediates that mediate alveolar development.
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Affiliation(s)
- Zhaoyu Sun
- Department Neurology & Neuroscience, Cancer Center H1200, New Jersey Medical School/University of Medicine and Dentistry of New Jersey, 205 South Orange Avenue, Newark, New Jersey 07101-1709, USA
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12
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Hue-Beauvais C, Chavatte-Palmer P, Aujean E, Dahirel M, Laigre P, Péchoux C, Bouet S, Devinoy E, Charlier M. An obesogenic diet started before puberty leads to abnormal mammary gland development during pregnancy in the rabbit. Dev Dyn 2011; 240:347-56. [DOI: 10.1002/dvdy.22536] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2010] [Indexed: 11/10/2022] Open
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13
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Iwamori T, Nukumi N, Itoh K, Kano K, Naito K, Kurohmaru M, Yamanouchi K, Tojo H. Bacteriostatic activity of Whey Acidic Protein (WAP). J Vet Med Sci 2009; 72:621-5. [PMID: 20009425 DOI: 10.1292/jvms.08-0331] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously reported the action of whey acidic protein (WAP) inhibiting the proliferation of mouse mammary epithelial cells in the experiments utilizing in vivo and in vitro systems. We report herein the bacteriostatic activity of WAP. Western blot analysis demonstrated successful isolation of WAP from whey fractions of rat milk by column chromatography. The WAP fraction inhibited the growth of Staphylococcus aureus JCM2413 in a dose-dependent manner, but did not inhibit the growth of Escherichia coli. The bacteriostatic activity of WAP was highest at pH 6.6 and was not affected by the presence of 150 mM NaCl. A scanning electron micrograph of bacteria treated with WAP exhibited the disruption of the bacterial cell walls.
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Affiliation(s)
- Tokuko Iwamori
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
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14
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Zhang Z, Zhang B, Nie X, Liu Q, Xie F, Shang D. Transcriptome Analysis and Identification of Genes Related to Immune Function in Skin of the Chinese Brown Frog. Zoolog Sci 2009; 26:80-6. [DOI: 10.2108/zsj.26.80] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Zhewen Zhang
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116029, China
| | - Bing Zhang
- Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xiaona Nie
- College of Computer and Information Technology, Liaoning Normal University, Dalian 116029, China
| | - Qingkun Liu
- College of Computer and Information Technology, Liaoning Normal University, Dalian 116029, China
| | - Fuding Xie
- College of Computer and Information Technology, Liaoning Normal University, Dalian 116029, China
| | - Dejing Shang
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116029, China
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15
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Hematopoietic-specific Stat5-null mice display microcytic hypochromic anemia associated with reduced transferrin receptor gene expression. Blood 2008; 112:2071-80. [PMID: 18552213 DOI: 10.1182/blood-2007-12-127480] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Iron is essential for all cells but is toxic in excess, so iron absorption and distribution are tightly regulated. Serum iron is bound to transferrin and enters erythroid cells primarily via receptor-mediated endocytosis of the transferrin receptor (Tfr1). Tfr1 is essential for developing erythrocytes and reduced Tfr1 expression is associated with anemia. The transcription factors STAT5A/B are activated by many cytokines, including erythropoietin. Stat5a/b(-/-) mice are severely anemic and die perinatally, but no link has been made to iron homeostasis. To study the function of STAT5A/B in vivo, we deleted the floxed Stat5a/b locus in hematopoietic cells with a Tie2-Cre transgene. These mice exhibited microcytic, hypochromic anemia, as did lethally irradiated mice that received a transplant of Stat5a/b(-/-) fetal liver cells. Flow cytometry and RNA analyses of erythroid cells from mutant mice revealed a 50% reduction in Tfr1 mRNA and protein. We detected STAT5A/B binding sites in the first intron of the Tfr1 gene and found that expression of constitutively active STAT5A in an erythroid cell line increased Tfr1 levels. Chromatin immunoprecipitation experiments confirmed the binding of STAT5A/B to these sites. We conclude that STAT5A/B is an important regulator of iron update in erythroid progenitor cells via its control of Tfr1 transcription.
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16
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Nukumi N, Iwamori T, Kano K, Naito K, Tojo H. Whey acidic protein (WAP) regulates the proliferation of mammary epithelial cells by preventing serine protease from degrading laminin. J Cell Physiol 2007; 213:793-800. [PMID: 17541952 DOI: 10.1002/jcp.21155] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Whey acidic protein (WAP) is a major whey protein in milk that has structural similarity to the family of serine protease inhibitors with WAP motif domains characterized by a four-disulfide core. We previously reported that enforced expression of the mouse WAP transgene in mammary epithelial cells inhibits their proliferation in vitro and in vivo by means of suppressing cyclin D1 expression (Nukumi et al., 2004, Dev Biol 274: 31-44). This study was conducted in order to clarify the molecular mechanism of the inhibitory function of WAP in HC11 cells, a mammary epithelial cell line. The assembly of laminin, a component in the extracellular matrix, was much more prominent around WAP-clonal HC11 cells that stably expressed the WAP transgene than around mock-clonal HC11 cells, and the proliferation of WAP-clonal HC11 cells was particularly inhibited in the presence of laminin. A laminin degradation assay demonstrated that WAP inhibited the activity of the pancreatic elastase-mediated cleavage of laminin B1 and the phosphorylation of ERK1/2. ERK1/2 phosphorylation was blocked by an inhibitor of the epidermal growth factor (EGF) receptor AG1478. Treatment with pancreatic elastase was found to enhance the proliferation of mock-clonal HC11 cells, but had no effect on that of WAP-clonal HC11 cells. The proliferation of WAP-clonal HC11 cells was recovered by the addition of exogenous EGF. We concluded that WAP plays some role in regulating the proliferation of mammary epithelial cells by preventing elastase-type serine protease from carrying out laminin degradation and thereby suppressing the MAP kinase signal pathway.
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Affiliation(s)
- Naoko Nukumi
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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17
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Wu HT, Lin CS, Huang MC. In vitro and ex vivo green fluorescent protein expression in alveolar mammary epithelial cells and mammary glands driven by the distal 5'-regulative sequence and intron 1 of the goat beta-casein gene. Reprod Fertil Dev 2007; 15:231-9. [PMID: 12921698 DOI: 10.1071/rd01050] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2002] [Accepted: 05/02/2003] [Indexed: 11/23/2022] Open
Abstract
The 5'-regulative sequence and intron 1 of the goat beta-casein gene from -4044 to +2123 bp was cloned and fused with the reporter gene of green fluorescent protein (GFP) to create a plasmid termed pGB562/GFP. To detect GFP expression, pGB562/GFP was transfected in vitro via liposomes into the mammary epithelial cell line NMuMG. Cells could not express GFP unless the transfected NMuMG cells lined up to create functional alveoli. These functional cells were cultured with lactogenic hormones, including insulin, dexamethasone and prolactin, and were grown on a layer of the extracellular matrix Matrigel. Green fluorescent protein expression levels in NMuMG cells were 25-, 55- and 42-fold those in the control group at 24, 48, and 72 h after pGB562/GFP transfection respectively. In addition, pGB562/GFP was transfected ex vivo by electroporation into mammary gland fragments and cells were then cultured in vitro with a supplement of lactogenic hormones. Strong GFP expression localized in fragments of the mammary gland was observed 24 h after gene transfer. The novel strategy of ex vivo gene transfer into mammary tissue using GFP as a reporter gene to detect the function of a tissue-specific promoter is efficient and convenient. The data obtained herein reveal that the 5'-regulative sequence and intron 1 of the 6.2 kb goat beta-casein gene can enhance the efficiency of transgene expression. Thus, the GB562 sequence may act as a good promoter and effectively elevate the production of exogenous protein in mammary glands.
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Affiliation(s)
- Hsi-Tien Wu
- Institute of Animal Science, National Chung-Hsing University, Taichung, Taiwan
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18
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Nukumi N, Iwamori T, Kano K, Naito K, Tojo H. Reduction of tumorigenesis and invasion of human breast cancer cells by whey acidic protein (WAP). Cancer Lett 2007; 252:65-74. [PMID: 17215074 DOI: 10.1016/j.canlet.2006.12.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 11/22/2006] [Accepted: 12/05/2006] [Indexed: 11/30/2022]
Abstract
Whey acidic protein (WAP) is a major component of whey, which has two or three WAP motif domains characterized by a four-disulfide core (4-DSC) structure similar to the serine protease inhibitor. We have previously found that WAP inhibits the proliferation of mammary epithelial cells in vitro and in vivo [N. Nukumi, K. Ikeda, M. Osawa, T. Iwamori, K. Naito, H. Tojo, Regulatory function of whey acidic protein in the proliferation of mouse mammary epithelial cells in vivo and in vitro, Dev. Biol. 274 (2004) 31-44]. We report herein that WAP also reduces the progression of human breast cancer cells (MCF-7 and MDA-MB-453 cells). We have demonstrated that the forced expression of WAP in MCF-7 cells reduces the proliferation in either the presence or absence of estrogen. The tumor progression of WAP-expressing MCF-7 cells in nude mice is significantly suppressed more than that of mock-MCF-7 cells following the reduced expression of angiopoietin-2 gene. We have confirmed that the invasive activity of breast cancer cells is reduced to approximately 30% of that of mock cells by the forced expression of exogenous WAP through its inhibition of degradation of laminin. These data suggest that WAP has a protease-inhibitory function on the progression of breast cancer cells. It is therefore possible to utilize WAP as therapeutic protein against tumorigenesis of breast cancer.
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Affiliation(s)
- Naoko Nukumi
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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19
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Jäger R. Targeting the death machinery in mammary epithelial cells: Implications for breast cancer from transgenic and tissue culture experiments. Crit Rev Oncol Hematol 2007; 63:231-40. [PMID: 17604639 DOI: 10.1016/j.critrevonc.2007.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 05/08/2007] [Accepted: 05/23/2007] [Indexed: 12/11/2022] Open
Abstract
Apoptosis plays important roles in the development of the mammary gland, and its impairment has been speculated to promote breast cancer. In mammary epithelial cells apoptosis is triggered via the intrinsic pathway which is controlled by interactions between pro- and anti-apoptotic members of the Bcl-2 protein family. The impact of impairing this pathway on the development of breast cancer has been addressed experimentally using transgenic mouse models. Neither overexpression of anti-apoptotic Bcl-2 nor a deficiency of pro-apoptotic Bax were tumorigenic on their own in mammary glands of transgenic mice. Both ways of impairing apoptosis, however, promoted mammary tumorigenesis elicited by c-myc or SV40 T antigen. Likewise, inhibition of the intrinsic pathway in a three-dimensional mammary tissue culture model was insufficient to generate solid aggregates resembling early breast cancer stages but required the concomitant activity of proliferation-stimulating oncogenes. These two experimental approaches have thus substantiated the concept of apoptosis acting as a tumor suppressor mechanism, however point towards a complex picture in which alternative routes to cell death may be involved.
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Affiliation(s)
- Richard Jäger
- Department of Developmental Pathology, Institute for Pathology, Bonn Medical School, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany.
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20
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Oh KB, Stanton MJ, West WW, Todd GL, Wagner KU. Tsg101 is upregulated in a subset of invasive human breast cancers and its targeted overexpression in transgenic mice reveals weak oncogenic properties for mammary cancer initiation. Oncogene 2007; 26:5950-9. [PMID: 17369844 DOI: 10.1038/sj.onc.1210401] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Previous studies reported that the Tumor Susceptibility Gene 101 (TSG101) is upregulated in selected human malignancies, and the expression of exogenous Tsg101 was suggested to transform immortalized fibroblasts in culture. To date, the potential oncogenic properties of Tsg101 have not been examined in vivo owing to the lack of appropriate model systems. In this study, we show that Tsg101 is highly expressed in a subset of invasive human breast cancers. Based on this observation, we generated the first transgenic mouse model with a targeted overexpression of Tsg101 in the developing mammary gland to test whether exogenous Tsg101 is capable of initiating tumorigenesis. Normal functionality of exogenous Tsg101 was tested by rescuing the survival of Tsg101-deficient mammary epithelial cells in conditional knockout mice. The overexpression of Tsg101 resulted in increased phosphorylation of the epidermal growth factor receptor and downstream activation of MAP kinases. Despite an increase in the activation of these signal transducers, the mammary gland of females expressing exogenous Tsg101 developed normally throughout the reproductive cycle. In aging females, the overexpression of Tsg101 seemed to increase the susceptibility of mammary epithelia toward malignant transformation. However, owing to the long latency of tumor formation and the sporadic occurrence of bona fide mammary cancers, we conclude that the Tsg101 protein has only weak oncogenic properties. Instead of cancer initiation, it is therefore likely that Tsg101 plays a more predominant role in the progression of a subset of spontaneously arising breast cancers.
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Affiliation(s)
- K B Oh
- Eppley Institute for Research in Cancer and Allied Diseases, 986805 University of Nebraska Medical Center, Omaha, NE 68198, USA
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21
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Li S, Chang S, Qi X, Richardson JA, Olson EN. Requirement of a myocardin-related transcription factor for development of mammary myoepithelial cells. Mol Cell Biol 2006; 26:5797-808. [PMID: 16847332 PMCID: PMC1592772 DOI: 10.1128/mcb.00211-06] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mammary gland consists of a branched ductal system comprised of milk-producing epithelial cells that form ductile tubules surrounded by a myoepithelial cell layer that provides contractility required for milk ejection. Myoepithelial cells bear a striking resemblance to smooth muscle cells, but they are derived from a different embryonic cell lineage, and little is known of the mechanisms that control their differentiation. Members of the myocardin family of transcriptional coactivators cooperate with serum response factor to activate smooth muscle gene expression. We show that female mice homozygous for a loss-of-function mutation of the myocardin-related transcription factor A (MRTF-A) gene are unable to effectively nurse their offspring due to a failure in maintenance of the differentiated state of mammary myoepithelial cells during lactation, resulting in apoptosis of this cell population, a consequent inability to release milk, and premature involution. The phenotype of MRTF-A mutant mice reveals a specific and essential role for MRTF-A in mammary myoepithelial cell differentiation and points to commonalities in the transcriptional mechanisms that control differentiation of smooth muscle and myoepithelial cells.
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Affiliation(s)
- Shijie Li
- Department of Molecular Biology, The University of Texas Southwestern Medical Center at Dallas, 6000 Harry Hines Blvd., Dallas, TX 75390, USA
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22
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Nukumi N, Seki M, Iwamori T, Yada T, Naito K, Tojo H. Analysis of the Promoter of Mutated Human Whey Acidic Protein (WAP) Gene. J Reprod Dev 2006; 52:315-20. [PMID: 16462094 DOI: 10.1262/jrd.17068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although whey acidic protein (WAP) has been identified in the milk of a range of species, it has been predicted that WAP is not secreted into human milk as a result of critical point mutations within the coding region. In the present study, we first investigated computationally the promoter region of mutated human WAP genes by comparing with those of other known WAP genes. Computational database analyses showed that the human WAP promoter region was highly conserved, as in other species with milk WAP. Next, we evaluated the activity of the human WAP promoter (2.6 kb) using a reporter gene assay. MCF-7 cells were stably transfected with the hWAP/hGH (human growth hormone) fusion gene, cultured on Matrigel, and treated with lactogenic hormones. Radioimmunoassay detected hGH in the culture medium, indicating that the human WAP promoter was responsible for the lactogenic hormones. The human WAP promoter was significantly more active in MCF-7 cells than the mouse WAP promoter (2.4 kb). The present results provide us with important information on the molecular evolution of milk protein genes.
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Affiliation(s)
- Naoko Nukumi
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan
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23
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Krepulat F, Löhler J, Heinlein C, Hermannstädter A, Tolstonog GV, Deppert W. Epigenetic mechanisms affect mutant p53 transgene expression in WAP-mutp53 transgenic mice. Oncogene 2005; 24:4645-59. [PMID: 15870706 DOI: 10.1038/sj.onc.1208557] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We describe the construction and phenotypic characterization of 23 whey acidic protein (WAP)-mutp53 transgenic mouse lines. The mutp53-expressing lines showed a mosaic expression pattern for the transgenes, leading to a heterogeneous yet mouse line-specific expression pattern for mutp53 upon induction. Only few lines were obtained, in which the majority of the induced mammary epithelial cells expressed the mutp53 transgene, most of the transgenic lines did not express mutp53, or expressed the transgene in less than 2% of the induced mammary epithelial cells. Hormone requirements for mutp53 transgene expression from the WAP-promoter differed in high and low expressing lines, being low in high expressing lines, and even lower in multiparous mutp53 mice, where persistent expression of the transgene occurred. Repeated induction of mutp53 expression through repeated parturition resulted in the formation of expanding mutp53-expressing foci within the mammary alveolar epithelium. The data suggest that epigenetic mechanisms play a role in modulating the expression of the mutp53 transgene. To support this idea, we crossed a nonexpressing WAP-mutp53 line with a strongly SV40 T-antigen-expressing WAP-T mouse line. In the bitransgenic mice, T-antigen-induced chromatin remodeling led to re-expression of epigenetically silenced mutp53 transgene(s). In these mice, mutp53 expression was much more variable compared to SV40 T-antigen expression, and seemed to depend on the coexpression of SV40 T-antigen. Mutp53 expression in this system thus resembles the situation in many human tumors, where one can observe a heterogeneous expression of mutp53, despite a homogeneous distribution of the p53 mutation in the tumor cells.
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Affiliation(s)
- Frauke Krepulat
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Martinistrasse 52, D-20251 Hamburg, Germany
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24
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Nukumi N, Iwamori T, Naito K, Tojo H. Whey acidic protein (WAP) depresses the proliferation of mouse (MMT) and human (MCF-7) mammary tumor cells. J Reprod Dev 2005; 51:649-56. [PMID: 16046839 DOI: 10.1262/jrd.17040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously reported that the enforced expression of exogenous whey acidic protein (WAP) significantly inhibited the proliferation of mouse mammary epithelial cells (HC11 and EpH4/H6 cells). This paper presents the first evidence that WAP also depresses the proliferation of mammary tumor cells from mouse (MMT cells) and human (MCF-7 cells). We established WAP-clonal MMT and MCF-7 cell lines, and confirmed the secretion of WAP from the WAP-clonal cells into culture medium. The enforced expression of WAP significantly inhibited the proliferation of MMT and MCF-7 cells in in vitro culture. FACScan analyses revealed that G0/G1 phase cell-cycle progression was disordered and elongated in the WAP-clonal MMT and MCF-7 cells compared to that of the control cells. The expression of cyclin D1 was significantly decreased in the WAP-clonal MMT and MCF-7 cells, suggesting that progression from the G1 to the S phase was delayed in the WAP-clonal cells. The present results indicate that WAP plays a negative regulatory role in the cell-cycle progression of mammary tumor cells via a paracrine mechanism.
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Affiliation(s)
- Naoko Nukumi
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, University of Tokyo, Japan.
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25
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Butler SP, O'Sickey TK, Lord ST, Lubon H, Gwazdauskas FC, Velander WH. Secretion of recombinant human fibrinogen by the murine mammary gland. Transgenic Res 2005; 13:437-50. [PMID: 15587268 DOI: 10.1007/s11248-004-9589-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Transgenic animals secreting individual chains and assembled fibrinogen were produced to evaluate the capacity of the mammary gland for maximizing assembly, glycosylation and secretion of recombinant human fibrinogen (rhfib). Transgenes were constructed from the 4.1 kbp murine Whey Acidic Protein promoter (mWAP) and the three cDNAs coding for the Aalpha, Bbeta and gamma fibrinogen chains. Transgenic mice secreted fully assembled fibrinogen into milk at concentrations between 10 and 200 microg/ml, with total secretion of subunits approaching 700 microg/ml in milk. Partially purified fibrinogen was shown to form a visible and stable clot after treatment with human thrombin and factor XIII. The level of assembled fibrinogen was proportional to the lowest amount of subunit produced where both the Bbeta and gamma chains were rate limiting. Both the Bbeta and gamma chains were glycosylated when co-expressed and the degree of saccharide maturation was dependent on expression level, with processing preferred for gamma chains over Bbeta chains. Also, the subunit complexes gamma2, Aalphagamma2 and the individual subunits Aalpha, Bbeta and gamma were found as secretion products. When the Bbeta was secreted individually, the glycosylation profile of the molecule was of a mature complex saccharide indicating recognition of the molecule by the glycosylation pathway without association with other fibrinogen chains. To date secretion of Bbeta chain has been not observed in any cell type, suggesting that the secretion pathway in mammary epithelia is less restrictive than that occurring in hepatocytes and other cells previously used to study fibrinogen assembly.
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Affiliation(s)
- Stephen P Butler
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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26
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Nukumi N, Ikeda K, Osawa M, Iwamori T, Naito K, Tojo H. Regulatory function of whey acidic protein in the proliferation of mouse mammary epithelial cells in vivo and in vitro. Dev Biol 2004; 274:31-44. [PMID: 15355786 DOI: 10.1016/j.ydbio.2004.04.040] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Revised: 03/30/2004] [Accepted: 04/28/2004] [Indexed: 11/26/2022]
Abstract
Although possible biological functions of whey acidic protein (WAP) have been suggested, few studies have focused on investigating the function of WAP. This paper describes evidence for WAP function in lobulo-alveolar development in mammary glands in vivo and in the cell cycle progression of mammary epithelial cells in vitro. Ubiquitous overexpression of WAP transgene impaired only lobulo-alveolar development in the mammary glands of transgenic female mice but not other physiological functions, indicating that the inhibitory function of WAP is specific to mammary alveolar cells. The forced expression of WAP significantly inhibited the proliferation of mouse mammary epithelial cells (HC11 cells and EpH4/K6 cells), whereas it did not affect that of NIH3T3 cells. Co-culturing of WAP-clonal cells and control cells using a transwell insert demonstrated that WAP inhibited the proliferation of HC11 cells through a paracrine action but not that of NIH3T3 cells, and that WAP was able to bind to HC11 cells but not to NIH3T3 cells. Apoptosis was not enhanced in the HC11 cells with stable WAP expression (WAP-clonal HC11 cells). BrdU incorporation and FACScan analyses revealed that cell cycle progression from the G0/G1 to the S phase was inhibited in the WAP-clonal HC11 cells. Among G1 cyclins, the expression of cyclin D1 and D3 was significantly decreased in the WAP-clonal HC11 cells. The present results provide the first documented evidence that WAP plays a negative regulatory role in the cell cycle progression of mammary epithelial cells through an autocrine or paracrine mechanism in vivo.
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Affiliation(s)
- Naoko Nukumi
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
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27
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Cui Y, Riedlinger G, Miyoshi K, Tang W, Li C, Deng CX, Robinson GW, Hennighausen L. Inactivation of Stat5 in mouse mammary epithelium during pregnancy reveals distinct functions in cell proliferation, survival, and differentiation. Mol Cell Biol 2004; 24:8037-47. [PMID: 15340066 PMCID: PMC515028 DOI: 10.1128/mcb.24.18.8037-8047.2004] [Citation(s) in RCA: 393] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study explored the functions of the signal transducers and activators of transcription 5a and 5b (referred to as Stat5 here) during different stages of mouse mammary gland development by using conditional gene inactivation. Mammary gland morphogenesis includes cell specification, proliferation and differentiation during pregnancy, cell survival and maintenance of differentiation throughout lactation, and cell death during involution. Stat5 is activated by prolactin, and its presence is mandatory for the proliferation and differentiation of mammary epithelium during pregnancy. To address the question of whether Stat5 is also necessary for the maintenance and survival of the differentiated epithelium, the two genes were deleted at different time points. The 110-kb Stat5 locus in the mouse was bracketed with loxP sites, and its deletion was accomplished by using two Cre-expressing transgenic lines. Loss of Stat5 prior to pregnancy prevented epithelial proliferation and differentiation. Deletion of Stat5 during pregnancy, after mammary epithelium had entered Stat5-mediated differentiation, resulted in premature cell death, indicating that at this stage epithelial cell proliferation, differentiation, and survival require Stat5.
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Affiliation(s)
- Yongzhi Cui
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0822, USA
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28
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Ikeda K, Nukumi N, Iwamori T, Osawa M, Naito K, Tojo H. Inhibitory function of whey acidic protein in the cell-cycle progression of mouse mammary epithelial cells (EpH4/K6 cells). J Reprod Dev 2004; 50:87-96. [PMID: 15007206 DOI: 10.1262/jrd.50.87] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although the biological role for whey acidic protein (WAP) in milk has been suggested, its true function is not known. This paper describes evidence for WAP function in the cell-cycle progression of EpH4/K6 (EpH4), mammary epithelial cells in vitro. The forced expression of exogenous WAP significantly impaired the proliferation of EpH4 cells, whereas it did not affect that of NIH3T3 cells. Apoptosis was not enhanced in the EpH4 cells with stable expression of WAP (WAP-clonal EpH4 cells). The analyses of BrdU incorporation revealed that forced WAP expression significantly reduced incorporation of BrdU in WAP-clonal EpH4 cells compared with control cells transfected with empty plasmid. Among G1 cyclins, the level expression of cyclins D1 was significantly lower in the WAP-clonal EpH4 cells than in control cells. The inhibitory action of WAP on the proliferation of EpH4 cells was enhanced by the presence of extracellular matrix (ECM), but not by the presence of a single component comprising ECM. The cultured medium of WAP-clonal EpH4 cells inhibited the proliferation of control cells without WAP expression. The present results indicate that WAP plays a negative regulatory role in the cell-cycle progression of mammary epithelial cells through an autocrine/paracrine mechanism.
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Affiliation(s)
- Kayoko Ikeda
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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29
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Schroeder JA, Masri AA, Adriance MC, Tessier JC, Kotlarczyk KL, Thompson MC, Gendler SJ. MUC1 overexpression results in mammary gland tumorigenesis and prolonged alveolar differentiation. Oncogene 2004; 23:5739-47. [PMID: 15221004 DOI: 10.1038/sj.onc.1207713] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
MUC1 is a transmembrane mucin that was initially cloned from malignant mammary epithelial cells as a tumor antigen. More than 90% of human breast carcinomas overexpress MUC1. Numerous studies have demonstrated an interaction between MUC1 and other oncogenic proteins such as beta-catenin, erbB receptors and c-Src, but a functional role for MUC1 in transformation has not been identified. We previously reported the development of transgenic mice that overexpress human MUC1 in the mouse mammary gland (MMTV-MUC1). Analysis of these transgenic mice at an early age demonstrated the ability of MUC1 to potentiate EGF-dependent activation of MAP kinase signaling pathways in the lactating mammary gland. We now report that multiparous MMTV-MUC1 transgenic mice stochastically develop unifocal mammary gland carcinomas late in life. Molecular analysis of these tumors shows a tumor-specific coimmunoprecipitation between MUC1 and beta-catenin. Examination of the contralateral glands in MMTV-MUC1 transgenics demonstrates that the development of frank carcinomas is accompanied by a failure of multiparous glands to undergo postlactational involution. Furthermore, uniparous MMTV-MUC1 transgenic mice display decreased postlactational apoptosis, elevated whey acidic protein expression and aberrant pErk2 activation. These findings are the first to determine that MUC1 overexpression promotes in vivo transformation of the mammary gland.
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Affiliation(s)
- Joyce A Schroeder
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Scottsdale, Scottsdale, AZ 85259, USA
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30
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William H. Velander, William N. Drohan, Henryk Lubon (deceased) and John L. Johnson (deceased) v. Ian Garner, Michael L. Dalrymple, Donna E. Prunkard, and Donald C. Foster(02-1366; Interference No. 104,242). Biotechnol Law Rep 2004. [DOI: 10.1089/073003104322838330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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31
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Saunier E, Dif F, Kelly PA, Edery M. Targeted expression of the dominant-negative prolactin receptor in the mammary gland of transgenic mice results in impaired lactation. Endocrinology 2003; 144:2669-75. [PMID: 12746331 DOI: 10.1210/en.2002-221038] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The F3-short form of the rat PRL receptor (F3-SPRLR) form acts as a dominant negative inhibitor in vitro. We have developed a transgenic mouse model in which the rat F3-SPRLR was expressed in mammary epithelium under the control of the mouse mammary tumor virus promoter. Two lines of mice were characterized and shown to express the transgene in the mammary gland. No developmental abnormalities or differences from wild-type littermates were observed on the basis of size, activity, or fertility. Mice with a low level of transgene expression had a mammary phenotype similar to the wild type. However, mice overexpressing the transgene (levels much higher than those of the endogenous long PRLR transcript) had impaired mammary gland differentiation and lactation. In these mice, whole-mount and histological analyses demonstrated normal ductal development, but severely reduced lobuloalveolar outgrowth. signal transducer and activator of transcription-5 phosphorylation and expression of beta-casein and whey acidic protein gene were decreased. In vivo bromodeoxyuridine incorporation at midpregnancy showed that the reduction in mammary development was not due to an inhibition of ductal growth and side-branching. This model demonstrates for the first time in vivo a function of the SPRLR and a local and targeted effect of PRL on the mammary gland that are essential for its function, but not for its development.
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Affiliation(s)
- Elise Saunier
- Institut National de la Santé et de la Recherche Médicale, Unité 344, Endocrinologie Moléculaire, Faculté de Médecine Necker, 75730 Paris, France
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32
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Abstract
Position effects in animal transgenesis have prevented the reproducible success and limited the initial expectations of this technique in many biotechnological projects. Historically, several strategies have been devised to overcome such position effects, including the progressive addition of regulatory elements belonging to the same or to a heterologous expression domain. An expression domain is thought to contain all regulatory elements that are needed to specifically control the expression of a given gene in time and space. The lack of profound knowledge on the chromatin structure of expression domains of biotechnological interest, such as mammary gland-specific genes, explains why most standard expression vectors have failed to drive high-level, position-independent, and copy-number-dependent expression of transgenes in a reproducible manner. In contrast, the application of artificial chromosome-type constructs to animal transgenesis usually ensures optimal expression levels. YACs, BACs, and PACs have become crucial tools in animal transgenesis, allowing the inclusion of distant key regulatory sequences, previously unknown, that are characteristic for each expression domain. These elements contribute to insulating the artificial chromosome-type constructs from chromosomal position effects and are fundamental in order to guarantee the correct expression of transgenes.
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Affiliation(s)
- Lluís Montoliu
- Centro Nacional de Biotecnología (CNB-CSIC), Department of Molecular and Cellular Biology, Madrid, Spain.
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33
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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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34
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Kingsley-Kallesen M, Mukhopadhyay SS, Wyszomierski SL, Schanler S, Schütz G, Rosen JM. The mineralocorticoid receptor may compensate for the loss of the glucocorticoid receptor at specific stages of mammary gland development. Mol Endocrinol 2002; 16:2008-18. [PMID: 12198239 DOI: 10.1210/me.2002-0103] [Citation(s) in RCA: 26] [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
To study the role of glucocorticoid receptor (GR) at different stages of mammary gland development, mammary anlage were rescued from GR-/- mice by transplantation into the cleared fat pad of wild-type mice. In virgin mice, GR-/- outgrowths displayed abnormal ductal morphogenesis characterized by distended lumena, multiple layers of luminal epithelial cells in some regions along the ducts, and increased periductal stroma. In contrast, the loss of GR did not result in overt phenotypic changes in mammary gland development during pregnancy, lactation, and involution. Surprisingly, despite the known synergism between glucocorticoids and prolactin in the regulation of milk protein gene expression, whey acidic protein and beta-casein mRNA levels were unaffected in GR-/- transplants as compared with wild-type transplants. That mineralocorticoid receptor (MR) might compensate for the loss of GR was suggested by the detection of MR in the mammary gland at d 1 of lactation. This hypothesis was tested using explant cultures derived from the GR-/- transplants in which the mineralocorticoid fludrocortisone was able to synergistically induce beta-casein gene expression in the presence of prolactin and insulin. These studies suggest that MR may compensate for the absence of GR at some, but not at all stages of mammary gland development.
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Affiliation(s)
- Michelle Kingsley-Kallesen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030-3498, USA
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35
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Wintermantel TM, Mayer AK, Schütz G, Greiner EF. Targeting mammary epithelial cells using a bacterial artificial chromosome. Genesis 2002; 33:125-30. [PMID: 12124945 DOI: 10.1002/gene.10097] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe the generation of transgenic mouse lines expressing Cre recombinase in epithelial cells of the lactating mammary gland. As an expression vector, we used a P1-derived bacterial artificial chromosome (PAC) which harbors the gene for the secretory milk protein, whey acidic protein (Wap). Using homologous recombination in E. coli, the PAC was modified to carry the improved coding sequence of Cre recombinase (iCre). Transgenic lines carrying the WAPiCre PAC express Cre recombinase efficiently in the majority of mammary epithelial cells upon lactation. Of only four transgenic lines produced, three express Cre recombinase to a high efficiency. LoxP-flanked DNA sequences are recombined in virtually all epithelial cells of WAPiCre transgenic mice at lactation day 3.
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Affiliation(s)
- Tim M Wintermantel
- Division Molecular Biology of the Cell I, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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36
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Sato M, Watanabe T, Oshida A, Nagashima A, Miyazaki JI, Kimura M. Usefulness of double gene construct for rapid identification of transgenic mice exhibiting tissue-specific gene expression. Mol Reprod Dev 2001; 60:446-56. [PMID: 11746955 DOI: 10.1002/mrd.1109] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Identification of transgenics still requires PCR and genomic Southern blot hybridization of genomic DNA isolated from tail pieces. Furthermore, identification of transgene-expressing transgenics (hereafter called "expressor") requires mRNA analyses (RT-PCR and Northern blot hybridization) or protein analysis (Western blotting and immunohistochemical staining using specific antibodies). These approaches are often labor-intensive and time-consuming. We developed a technique that simplifies the process of screening expressor transgenics using enhanced green fluorescent protein (EGFP), a noninvasive reporter recently utilized in a variety of organisms, including mice, as a tag. We constructed a MNCE transgene consisting of two expression units, MBP-NCre (termed "MN") and CAG-EGFP (termed "CE"). MN consists of a myelin basic protein (MBP) promoter and NCre gene (Cre gene carrying a nuclear localization signal (NLS) sequence at its 5' end). CE consists of a promoter element, CAG composed of cytomegalovirus (CMV) enhancer and chicken beta-actin promoter, and EGFP cDNA. Of a total of 72 F0 mice obtained after pronuclear injection of MNCE at 1-cell egg stage, 15 were found to express EGFP when the tail, eye, and inner surface of the ear were inspected for EGFP fluorescence under UV illumination at weaning stage. These fluorescent mice were found to possess MNCE and to express NCre mRNA in a brain-specific manner. Mice exhibiting no fluorescence were transgenic or nontransgenic. Mice carrying MNCE, but exhibiting no fluorescence, never expressed NCre mRNA in any organs tested. These findings indicate that (i) direct inspection of the surface of mice for fluorescence under UV illumination enables identification of expressor transgenics without performances of the molecular biological analyses mentioned above, and (ii) systemic promoters such as CAG do not affect the tissue-specificity of a tissue-specific promoter such as MBP promoter, which is located upstream of CAG by approximately 2 kb.
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MESH Headings
- Actins/genetics
- Animals
- Blotting, Southern
- Brain/metabolism
- Cells, Cultured
- Chickens/genetics
- Cytomegalovirus/genetics
- DNA, Recombinant/genetics
- Enhancer Elements, Genetic/genetics
- Gene Expression
- Gene Expression Profiling/methods
- Genes, Reporter/genetics
- Green Fluorescent Proteins
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Mice
- Mice, Transgenic
- Myelin Basic Protein/genetics
- Organ Specificity
- Promoter Regions, Genetic/genetics
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Recombination, Genetic/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
- Transgenes/genetics
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Affiliation(s)
- M Sato
- Molecular Medicine Research Center, The Institute of Medical Sciences, Tokai University, Bohseidai, Isehara, Kanagawa 259-1193, Japan.
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37
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Walton KD, Wagner KU, Rucker EB, Shillingford JM, Miyoshi K, Hennighausen L. Conditional deletion of the bcl-x gene from mouse mammary epithelium results in accelerated apoptosis during involution but does not compromise cell function during lactation. Mech Dev 2001; 109:281-93. [PMID: 11731240 DOI: 10.1016/s0925-4773(01)00549-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In the mammary gland Bcl-x is the most abundant cell survival factor from the Bcl-2 family. Since Bcl-x null mice die around day 12 of embryogenesis, the relevance of this protein in organ development and function is poorly understood. In erythroid cells bcl-x gene expression is controlled by cytokines and the transcription factor Stat5 (signal transducer and activator of transcription). However, we identified that bcl-x RNA levels in mammary tissue from prolactin receptor- and Stat5-null mice were indistinguishable from wild type mice. We have proposed that Bcl-x might control the survival of mammary epithelial cells throughout pregnancy, lactation, and the early stages of involution, and we have now tested this hypothesis through the conditional deletion of the bcl-x gene from mouse mammary epithelium. Conditional (floxed) bcl-x alleles were excised from alveolar cells during pregnancy using a Cre transgene under the control of the whey acidic protein gene promoter. Deletion of the bcl-x gene from the entire epithelial compartment (ducts and alveoli) was achieved by expressing Cre-recombinase under control of the mouse mammary tumor virus long terminal repeat. The absence of Bcl-x did not compromise proliferation and differentiation of mammary ductal and alveolar epithelial cells in virgin mice and during pregnancy and lactation. However, epithelial cell death and tissue remodeling were accelerated in the bcl-x conditional knockout mice during the first stage of involution. Concomitant deletion of the bax gene did not significantly modify the Bcl-x phenotype. Our results suggest that Bcl-x is not essential during mammopoiesis, but is critical for controlled apoptosis during the first phase of involution.
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Affiliation(s)
- K D Walton
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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38
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Rival S, Attal J, Delville-Giraud C, Yerle M, Laffont P, Rogel-Gaillard C, Houdebine L. Cloning, transcription and chromosomal localization of the porcine whey acidic protein gene and its expression in HC11 cell line. Gene 2001; 267:37-47. [PMID: 11311554 DOI: 10.1016/s0378-1119(01)00388-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The whey acidic protein (WAP) is the major whey protein of rodent, rabbit and camel. Recently, it was identified in the milk of swine (Simpson et al., 1998. J. Mol. Endocrinol. 20, 27-35). In this paper, the cloning of the pig WAP cDNA and of bacterial artificial chromosome (BAC) construct containing the entire porcine WAP gene is reported. The comparison of the coding sequence of the pig WAP gene to rodent or lagomorph WAP sequence already published demonstrated that only exon sequences are partially conserved. The porcine WAP gene was localized on the subtelomeric region of the chromosome 18. The estimation of the expression of the swine WAP gene in the mammary gland from lactating animals revealed a high level of expression. In order to compare the expression level of the porcine WAP gene from the large genomic fragment which contained 70 kb downstream and 50 kb upstream the pig WAP gene or the smaller one (1 kb downstream and 2.4 kb upstream), these two genomic fragments were transfected in HC11 cell line. The BAC construct was expressed 15 times higher than the plasmid when reported to the integrated copy number. This report suggests that the HC11 cell line is a useful tool to identify the regulatory sequences of milk protein genes.
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Affiliation(s)
- S Rival
- Laboratoire de Biologie du Développement et Biotechnologies, Institut National de Recherche Agronomique, 78352 Jouy en Josas cedex, Cedex, France
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39
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Wall RJ, Paleyanda RK, Foster JA, Powell A, Rexroad C, Lubon H. DNA preparation method can influence outcome of transgenic animal experiments. Anim Biotechnol 2001; 11:19-32. [PMID: 10885809 DOI: 10.1080/10495390009525944] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In our continuing quest to improve the efficiency of producing transgenic animals, we have compared the influence of two transgene purification techniques on the efficiency of creating transgenic sheep and mice. Three hundred eighty-seven sheep zygotes and 2,737 mouse zygotes were microinjected with one of four transgenes. Transgenes were isolated from plasmid sequences either by agarose gel electrophoresis followed by gel extraction or by a single step sodium chloride gradient fractionation technique. Four transgenic sheep and 61 transgenic mice were produced. Both sheep and mice embryos responded similarly to transgene preparation methods. Overall, pregnancy rate was higher for recipients that received embryos injected with NaCl purified DNA (mean +/- SEM: 64 +/- 7% vs. 38 +/- 7%). Furthermore, offspring per zygote transferred (NaCl, 22 +/- 3% vs. Gel, 12 +/- 3%) and transgenics born per zygote transferred (NaCl, 3.9 +/- 0.6% vs. Gel, 1.5 +/- 0.6%) were higher when the NaCl purified DNA was used. However, the proportion of offspring born that were identified as transgenic did not differ between transgene purification methods. Transgenes responded differently to methods of preparation. One of the four genes yielded a significantly higher proportion of transgenics when the transgene was prepared by NaCl purification. These data suggest that on average the NaCl gradient purification technique results in a higher embryo survival rate to term for both sheep and mice, but the technique has no influence on rate of transgene integration.
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Affiliation(s)
- R J Wall
- Gene Evaluation and Mapping Laboratory, USDA, Beltsville, MD 20705, USA.
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40
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Gallego MI, Binart N, Robinson GW, Okagaki R, Coschigano KT, Perry J, Kopchick JJ, Oka T, Kelly PA, Hennighausen L. Prolactin, growth hormone, and epidermal growth factor activate Stat5 in different compartments of mammary tissue and exert different and overlapping developmental effects. Dev Biol 2001; 229:163-75. [PMID: 11133161 DOI: 10.1006/dbio.2000.9961] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prolactin (Prl)-induced phosphorylation of Stat (signal transducer and activator of transcription) 5 is considered a key event in functional mammary development and differentiation. We now demonstrate that not only Prl, but also growth hormone (GH) and epidermal growth factor (EGF), can activate Stat5 in mammary tissue. We investigated the roles of these hormones in mammary development using mice in which the respective receptors had been inactivated. Although Prl receptor (PrlR)-null mice are infertile, we were able to maintain pregnancies in a few mice by treatment with progesterone. Mammary tissue in these mice was severely underdeveloped and exhibited limited differentiation as assessed by the phosphorylation status of Stat5 and the expression of milk protein genes. PrlR +/- mice showed impaired mammary development and alveolar differentiation during pregnancy, which corresponded with reduced phosphorylation levels of Stat5a and 5b, and impaired expression of milk protein genes. Development of the glands in these mice was arrested at around day 13 of pregnancy. While Prl activated Stat5 only in the epithelium, GH and EGF activated Stat5 preferentially in the stroma. To assess the relevance of the GH receptor (GHR) in the mammary gland, we transplanted GHR-null epithelium into cleared fat pads of wild-type mice. These experiments demonstrated that the GHR in the epithelium is not required for functional mammary development. Similarly, the EGFR in the epithelium is not required for alveolar development. In contrast, epithelial PrlR is required for mammary development and milk protein gene expression during pregnancy. Although GH is not required for alveolar development, we were able to demonstrate its lactogenic function in cultured mammary epithelium from PrlR-null mice. However, ductal development in GHR-null mice was impaired, supporting the notion that GH signals through the stromal compartment. Our findings demonstrate that GH, Prl, and EGF activate Stat5 in separate compartments, which in turn reflects their specific roles in ductal and alveolar development and differentiation.
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Affiliation(s)
- M I Gallego
- Laboratory of Genetics and Physiology, National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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41
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Inuzuka H, Yamanouchi K, Tachi C, Tojo H. A transgenic mouse model for investigating the response of the upstream region of whey acidic protein (WAP) gene to various steroid hormones. Exp Anim 2001; 50:1-7. [PMID: 11326419 DOI: 10.1538/expanim.50.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The limitations of studies of clarification of response elements of whey acidic protein (WAP) gene to hormones using mammary cell lines has been shown. We studied the response of the upstream region (2.6 kb) of WAP to various steroid hormones using gonadectomized mWAP/hGH transgenic mice. Ovariectomy or castration for transgenic mice was performed at 10 days or 30 days post partum. Various steroid hormones were administered daily for 10 days to the gonadectomized transgenic mice after they reached 2 months of age. Prior to the hormonal administration and 24 hr after the final administration, blood was collected and the hGH levels in the plasma was measured by RIA. Daily doses of estradiol-17 beta were significantly more effective at increasing hGH levels in transgenic females ovariectomized at 10 days post partum than progesterone of an equal dose. A combined dose of progesterone and of estradiol-17 beta significantly amplified the increase of hGH levels accompanied by the great development of mammary glands, compared to a dose of progesterone alone. Corticosterone induced only a slight increase of hGH, while testosterone had no effect. The doses of gonadal steroid hormones did not induce an increase in hGH levels and development of mammary glands in the castrated transgenic males. The results showed that the response of 5' region of WAP requires at least some extended development of the mammary gland and that the 2.6 kb upstream region of the exogenous WAP gene contained the element responsive to ovarian hormones.
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Affiliation(s)
- H Inuzuka
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan
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42
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Albanese C, Reutens AT, Bouzahzah B, Fu M, D'Amico M, Link T, Nicholson R, Depinho RA, Pestell RG. Sustained mammary gland-directed, ponasterone A-inducible expression in transgenic mice. FASEB J 2000; 14:877-84. [PMID: 10783141 DOI: 10.1096/fasebj.14.7.877] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ability to regulate temporal- and spatial-specific expression of target genes in transgenic mice will facilitate analysis of gene function and enable the generation of murine models of human diseases. The genetic analysis of mammary gland tumorigenesis requires the development of mammary gland-specific transgenics, which are tightly regulated throughout the adult mammary epithelium. Analysis of genes implicated in mammary gland tumorigenesis has been hampered by mosaic transgene expression and the findings that homozygous deletion of several candidate genes (cyclin D1, Stat5A, prolactin receptor) abrogates normal mammary gland development. We describe the development of transgenic mouse lines in which sustained transgene expression was inducibly regulated, both specifically and homogeneously, in the adult mammary gland epithelium. Transgenes encoding RXRalpha and a chimeric ecdysone receptor under control of a modified MMTV-LTR, which targets mammary gland expression, were used. These transgenic 'receptor' lines were crossed with transgenic 'enhancer' lines in which the ecdysone/RXR binding site induced ligand-dependent expression of transgenic beta-galactosidase. Pharmacokinetic analysis of a highly bioactive ligand (ponasterone A), identified through screening ecdysteroids from local plants, demonstrated sustained release and transgene expression in vivo. This transgenic model with both tightly regulated and homogeneous transgene expression, which was sustained in vivo using ligands readily extracted from local flora, has broad practical applicability for genetic analysis of mammary gland disease.
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Affiliation(s)
- C Albanese
- The Albert Einstein Cancer Center, Department of Developmental and Molecular Biology, Department of Medicine and. Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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43
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Schulze-Garg C, Löhler J, Gocht A, Deppert W. A transgenic mouse model for the ductal carcinoma in situ (DCIS) of the mammary gland. Oncogene 2000; 19:1028-37. [PMID: 10713686 DOI: 10.1038/sj.onc.1203281] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ductal carcinoma in situ (DCIS) of the mammary gland represents an early, pre-invasive stage in the development of invasive breast carcinoma and is increasingly diagnosed since the introduction of high-quality mammography screening. Uncertainties in the prognosis for patients with DCIS have caused a controversial discussion about adequate treatment, and it is suspected that most patients undergoing mastectomy may be overtreated. In order to improve treatment and treatment decision, it therefore is highly desirable to identify prognostic markers and therapeutic targets for DCIS. We here introduce a set of transgenic mice (WAP-T and WAP-T-NP lines) presenting with various morphological forms of DCIS-like lesions. In these mice the SV40 large tumor antigen is specifically induced in epithelial cells of the terminal duct lobular units (TDLU). As a consequence of continuous expression of the oncogene, the animals develop multifocal DCIS and consequently invasive carcinoma within strain specific periods of latency. DCIS lesions in transgenic mice exhibit distinct architectural and cytological features which closely resemble those commonly present in humans. We therefore propose these transgenic lines as an experimental model to study the underlying molecular events leading to DCIS and its progression to invasive disease.
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MESH Headings
- Animals
- Antigens, Polyomavirus Transforming/genetics
- Biomarkers, Tumor
- Breast Neoplasms/pathology
- Carcinoma, Ductal, Breast/genetics
- Carcinoma, Ductal, Breast/pathology
- Epithelial Cells/pathology
- Female
- Humans
- Male
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred Strains
- Mice, Transgenic
- Milk Proteins/genetics
- Neoplasm Invasiveness/genetics
- Predictive Value of Tests
- Promoter Regions, Genetic
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44
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Stegalkina SS, Guerrero A, Walton KD, Liu X, Robinson GW, Hennighausen L. Transcription originating in the long terminal repeats of the endogenous mouse mammary tumor virus MTV-3 is activated in Stat5a-null mice and picks Up hitchhiking exons. J Virol 1999; 73:8669-76. [PMID: 10482620 PMCID: PMC112887 DOI: 10.1128/jvi.73.10.8669-8676.1999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The enhancer within the long terminal repeats (LTRs) of acquired somatic mouse mammary tumor viruses (MMTV) can activate juxtaposed genes and induce mammary tumors. In contrast, germ line proviral MMTV genomes are integrated in the host genome and considered to be genetically confined transcription units. Here we demonstrate that transcription initiated in an MMTV provirus proceeds into flanking host sequences. We discovered multiple polyadenylated transcripts which are induced in Stat5a null mice. These range from 1.5 kb to more than 8 kb and are specifically expressed in mammary tissue from pregnant and lactating mice from the 129 but not C57BL/6 strain. The RNAs emanate from both LTRs of the endogenous MTV-3 provirus on chromosome 11 and proceed at least 10 kb into the juxtaposed genomic territory. Transcripts originating in the 5' LTR splice from the native splice site within the MMTV envelope gene into at least six exons, three of which contain functional internal splice sites. The combination of alternative splicing and the use of several polyadenylation sites ensure the generation of multiple transcripts. To date no significant open reading frame has been discovered. Furthermore, we demonstrate that transcription from the MMTV 5' LTR is highly active in the absence of Stat5a, a transcription factor that had been shown previously to be required for transcription from the MMTV LTR.
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Affiliation(s)
- S S Stegalkina
- 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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Wall R. Biotechnology for the production of modified and innovative animal products: transgenic livestock bioreactors. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s0301-6226(99)00030-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lubon H. Transgenic animal bioreactors in biotechnology and production of blood proteins. BIOTECHNOLOGY ANNUAL REVIEW 1999; 4:1-54. [PMID: 9890137 DOI: 10.1016/s1387-2656(08)70066-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The regulatory elements of genes used to target the tissue-specific expression of heterologous human proteins have been studied in vitro and in transgenic mice. Hybrid genes exhibiting the desired performance have been introduced into large animals. Complex proteins like protein C, factor IX, factor VIII, fibrinogen and hemoglobin, in addition to simpler proteins like alpha 1-antitrypsin, antithrombin III, albumin and tissue plasminogen activator have been produced in transgenic livestock. The amount of functional protein secreted when the transgene is expressed at high levels may be limited by the required posttranslational modifications in host tissues. This can be overcome by engineering the transgenic bioreactor to express the appropriate modifying enzymes. Genetically engineered livestock are thus rapidly becoming a choice for the production of recombinant human blood proteins.
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Affiliation(s)
- H Lubon
- Plasma Derivatives Department, American Red Cross, Rockville, Maryland, USA.
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Pfitzner E, Jähne R, Wissler M, Stoecklin E, Groner B. p300/CREB-binding protein enhances the prolactin-mediated transcriptional induction through direct interaction with the transactivation domain of Stat5, but does not participate in the Stat5-mediated suppression of the glucocorticoid response. Mol Endocrinol 1998; 12:1582-93. [PMID: 9773981 DOI: 10.1210/mend.12.10.0180] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Stat5 was discovered as a PRL-induced member of the Stat (signal transducer and activator of transcription) family. Its induction by many other cytokines and interleukins suggests that Stat5 plays a crucial role not only in mammary epithelial, but also in hematopoietic cells. Cell type- and promoter-specific functions of Stat5 are most likely modulated by the interaction with other transcription factors. We recently showed cross-talk between Stat5 and the glucocorticoid receptor. The activated glucocorticoid receptor forms a complex with Stat5 and enhances Stat5-mediated transcriptional induction. Conversely, Stat5 diminishes the induction of glucocorticoid-responsive genes. Here, we investigated the role of p300/CBP(CREB-binding protein), a transcriptional coactivator of several groups of transcription factors, in Stat5-mediated transactivation and in the cross-talk between Stat5 and the glucocorticoid receptor. p300/ CBP acts as a coactivator of Stat5. Its ectopic expression enhances PRL-induced Stat5-mediated transcriptional activation. Consistent with this observation, we find that the adenovirus E1A protein, which binds to p300/CBP, suppresses Stat5-induced transcriptional activation. This inhibition requires the Stat5 transactivation domain and the p300/CBP binding site of E1A. Coimmunoprecipitation and mammalian two-hybrid assays demonstrate a direct interaction between the carboxyl-terminal transactivation domain of Stat5 and p300/CBP. p300/CBP also positively interacts with the glucocorticoid receptor and enhances glucocorticoid receptor-dependent transcriptional activation of the mouse mammary tumor virus-long terminal repeat promoter. Overexpression of p300/CBP does not counteract the Stat5-mediated inhibition of glucocorticoid receptor-dependent transactivation, i.e. the repression of the glucocorticoid response by Stat5 is not a consequence of competition for limiting amounts of p300/CBP.
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Affiliation(s)
- E Pfitzner
- Institute for Experimental Cancer Research, Tumor Biology Center, Freiburg, Germany
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Wagner KU, Wall RJ, St-Onge L, Gruss P, Wynshaw-Boris A, Garrett L, Li M, Furth PA, Hennighausen L. Cre-mediated gene deletion in the mammary gland. Nucleic Acids Res 1997; 25:4323-30. [PMID: 9336464 PMCID: PMC147032 DOI: 10.1093/nar/25.21.4323] [Citation(s) in RCA: 418] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
To delete genes specifically from mammary tissue using the Cre-lox system, we have established transgenic mice expressing Cre recombinase under control of the WAP gene promoter and the MMTV LTR. Cre activity in these mice was evaluated by three criteria. First, the tissue distribution of Cre mRNA was analyzed. Second, an adenovirus carrying a reporter gene was used to determine expression at the level of single cells. Third, tissue specificity of Cre activity was determined in a mouse strain carrying a reporter gene. In adult MMTV-Cre mice expression of the transgene was confined to striated ductal cells of the salivary gland and mammary epithelial cells in virgin and lactating mice. Expression of WAP-Cre was only detected in alveolar epithelial cells of mammary tissue during lactation. Analysis of transgenic mice carrying both the MMTV-Cre and the reporter transgenes revealed recombination in every tissue. In contrast, recombination mediated by Cre under control of the WAP gene promoter was largely restricted to the mammary gland but occasionally observed in the brain. These results show that transgenic mice with WAP-Cre but not MMTV-Cre can be used as a powerful tool to study gene function in development and tumorigenesis in the mammary gland.
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Affiliation(s)
- K U Wagner
- Laboratory of Metabolism and Biochemistry, National Institute of Diabetes Digestive and Kidney Diseases and Laboratory of Genetic Disease Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Abstract
Amid the explosion of fundamental knowledge generated from transgenic animal models, a small group of scientists has been producing transgenic livestock with goals of improving animal production efficiency and generating new products. The ability to modify mammary-specific genes provides an opportunity to pursue several distinctly different avenues of research. The objective of the emerging gene "pharming" industry is to produce pharmaceuticals for treating human diseases. It is argued that mammary glands are an ideal site for producing complex bioactive proteins that can be cost effectively harvested and purified. Consequently, during the past decade, approximately a dozen companies have been created to capture the US market for pharmaceuticals produced from transgenic bioreactors estimated at $3 billion annually. Several products produced in this way are now in human clinical trials. Another research direction, which has been widely discussed but has received less attention in the laboratory, is genetic engineering of the bovine mammary gland to alter the composition of milk destined for human consumption. Proposals include increasing or altering endogenous proteins, decreasing fat, and altering milk composition to resemble that of human milk. Initial studies using transgenic mice to investigate the feasibility of enhancing manufacturing properties of milk have been encouraging. The potential profitability of gene "pharming" seems clear, as do the benefits of transgenic cows producing milk that has been optimized for food products. To take full advantage of enhanced milk, it may be desirable to restructure the method by which dairy producers are compensated. However, the cost of producing functional transgenic cattle will remain a severe limitation to realizing the potential of transgenic cattle until inefficiencies of transgenic technology are overcome. These inefficiencies include low rates of gene integration, poor embryo survival, and unpredictable transgene behavior.
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Affiliation(s)
- R J Wall
- Gene Evaluation and Mapping Laboratory, USDA-ARS-Livestock and Poultry Science Institute, Beltsville, MD 20705, USA
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Abstract
Gene transfer into somatic tissues is a tool for both the study of gene function in the basic science laboratory and for gene therapy and genetic immunization in the clinic. Biolistic processes can be used to deliver both viral and nonviral vectors into somatic tissues. This review discusses the advantages and disadvantages of three biolistic processes: jet injection, microparticle bombardment, and needle and syringe injection. Jet injection and needle and syringe injection can be used to deliver both viral and nonviral vectors. Both jet injection and microparticle bombardment can be used to target a broad range of tissues. Needle and syringe injection has been most widely used in muscle tissue. The choice of which biolistic process to use is dependent on the specific application.
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Affiliation(s)
- P A Furth
- Department of Medicine, University of Maryland Medical School, Baltimore, USA.
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