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Ahmad W, Panicker NG, Akhlaq S, Gull B, Baby J, Khader TA, Rizvi TA, Mustafa F. Global Down-regulation of Gene Expression Induced by Mouse Mammary Tumor Virus (MMTV) in Normal Mammary Epithelial Cells. Viruses 2023; 15:v15051110. [PMID: 37243196 DOI: 10.3390/v15051110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
Mouse mammary tumor virus (MMTV) is a betaretrovirus that causes breast cancer in mice. The mouse mammary epithelial cells are the most permissive cells for MMTV, expressing the highest levels of virus upon infection and being the ones later transformed by the virus due to repeated rounds of infection/superinfection and integration, leading eventually to mammary tumors. The aim of this study was to identify genes and molecular pathways dysregulated by MMTV expression in mammary epithelial cells. Towards this end, mRNAseq was performed on normal mouse mammary epithelial cells stably expressing MMTV, and expression of host genes was analyzed compared with cells in its absence. The identified differentially expressed genes (DEGs) were grouped on the basis of gene ontology and relevant molecular pathways. Bioinformatics analysis identified 12 hub genes, of which 4 were up-regulated (Angp2, Ccl2, Icam, and Myc) and 8 were down-regulated (Acta2, Cd34, Col1a1, Col1a2, Cxcl12, Eln, Igf1, and Itgam) upon MMTV expression. Further screening of these DEGs showed their involvement in many diseases, especially in breast cancer progression when compared with available data. Gene Set Enrichment Analysis (GSEA) identified 31 molecular pathways dysregulated upon MMTV expression, amongst which the PI3-AKT-mTOR was observed to be the central pathway down-regulated by MMTV. Many of the DEGs and 6 of the 12 hub genes identified in this study showed expression profile similar to that observed in the PyMT mouse model of breast cancer, especially during tumor progression. Interestingly, a global down-regulation of gene expression was observed, where nearly 74% of the DEGs in HC11 cells were repressed by MMTV expression, an observation similar to what was observed in the PyMT mouse model during tumor progression, from hyperplasia to adenoma to early and late carcinomas. Comparison of our results with the Wnt1 mouse model revealed further insights into how MMTV expression could lead to activation of the Wnt1 pathway independent of insertional mutagenesis. Thus, the key pathways, DEGs, and hub genes identified in this study can provide important clues to elucidate the molecular mechanisms involved in MMTV replication, escape from cellular anti-viral response, and potential to cause cell transformation. These data also validate the use of the MMTV-infected HC11 cells as an important model to study early transcriptional changes that could lead to mammary cell transformation.
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Affiliation(s)
- Waqar Ahmad
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
| | - Neena G Panicker
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
| | - Shaima Akhlaq
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
| | - Bushra Gull
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
| | - Jasmin Baby
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
| | - Thanumol A Khader
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
| | - Tahir A Rizvi
- Department of Microbiology and Immunology, College of Medicine and Health Sciences (CMHS), UAE University, Al Ain 15551, United Arab Emirates
- Zayed Center for Health Sciences (ZCHS), UAE University, Al Ain 15551, United Arab Emirates
- ASPIRE Research Institute in Precision Medicine, Abu Dhabi, UAE University, Al Ain 15551, United Arab Emirates
| | - Farah Mustafa
- Department of Biochemistry & Molecular Biology, College of Medicine and Health Sciences (CMHS), United Arab Emirates (UAE) University, Al Ain 15551, United Arab Emirates
- Zayed Center for Health Sciences (ZCHS), UAE University, Al Ain 15551, United Arab Emirates
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Raafat A, Bargo S, McCurdy D, Callahan R. The ANK repeats of Notch-4/Int3 activate NF-κB canonical pathway in the absence of Rbpj and causes mammary tumorigenesis. Sci Rep 2017; 7:13690. [PMID: 29057904 PMCID: PMC5651869 DOI: 10.1038/s41598-017-13989-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/25/2017] [Indexed: 01/14/2023] Open
Abstract
Transgenic mice expressing the Notch-4 intracellular domain (designated Int3) in the mammary gland have two phenotypes exhibited with 100% penetrance: arrest of mammary alveolar/lobular development and mammary tumorigenesis. Notch-4 signaling is mediated primarily through the interaction of Int3 with the transcription repressor/activator Rbpj. Interestingly, WAP-Int3/Rbpj knockout mice have normal mammary gland development but still developed mammary tumors with a slightly longer latency than the WAP-Int3 mice. Thus, Notch-induced mammary tumor development is Rbpj-independent. Here, we show that Int3 activates NF-κB in HC11 cells in absence of Rbpj through an association with the IKK signalosome. Int3 induced the canonical NF-κB activity and P50 phosphorylation in HC11 cells without altering the NF-κB2 pathway. The minimal domain within the Int3 protein required to activate NF-κB consists of the CDC10/Ankyrin (ANK) repeats domain. Treatment of WAP-Int3 tumor bearing mice with an IKK inhibitor resulted in tumor regression. In a soft agar assay, treatment of HC11-Int3 cells with P50-siRNA caused a significant decrease in colony formation. In addition, Wap-Int3/P50 knockout mice did not develop mammary tumors. This data indicates that the activation of NF-κB canonical signaling by Notch-4/Int3 is ANK repeats dependent, Rbpj-independent, and is mediated by IKK activation and P50 phosphorylation causing mammary tumorigenesis.
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Affiliation(s)
- Ahmed Raafat
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20814, USA.
| | - Sharon Bargo
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20814, USA
| | - David McCurdy
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20814, USA
| | - Robert Callahan
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20814, USA
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Callahan R, Chestnut BA, Raafat A. Original Research: Featured Article: Imatinib mesylate (Gleevec) inhibits Notch and c-Myc signaling: Five-day treatment permanently rescues mammary development. Exp Biol Med (Maywood) 2016; 242:53-67. [PMID: 27550925 DOI: 10.1177/1535370216665175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/28/2016] [Indexed: 12/31/2022] Open
Abstract
Wap-Int3 transgenic females expressing the Notch4 intracellular domain (designated Int3) from the whey acidic protein promoter exhibit two phenotypes in the mammary gland: blockage of lobuloalveolar development and lactation, and tumor development with 100% penetrance. Previously, we have shown that treatment of Wap-Int3 tumor bearing mice with Imatinib mesylate (Gleevec) is associated with complete regression of the tumor. In the present study, we show that treatment of Wap-Int3 mice during day 1 through day 6 of pregnancy with Gleevec leads to the restoration of their lobuloalveolar development and ability to lactate in subsequent pregnancies in absence of Gleevec treatment. In addition, these mice do not develop mammary tumors. We investigated the mechanism for Gleevec regulation of Notch signaling and found that Gleevec treatment results in a loss of Int3 protein but not of Int3 mRNA in HC11 mouse mammary epithelial cells expressing Int3. The addition of MG-132, a proteasome inhibitor, shows increased ubiquitination of Int3 in the presence of Gleevec. Thus, Gleevec affects the stability of Int3 by promoting the degradation of Int3 via E3 ubiquitin ligases targeting it for the proteasome degradation. Gleevec is a tyrosine kinase inhibitor that acts on c-Kit and PDGFR. Therefore, we investigated the downstream substrate kinase GSK3β to ascertain the possible role that this kinase might play in the stability of Int3. Data show that Gleevec degradation of Int3 is GSK3β dependent. We have expanded our study of the effects Gleevec has on tumorigenesis of other oncogenes. We have found that anchorage-independent growth of HC11-c-Myc cells as well as tumor growth in nude mice is inhibited by Gleevec treatment. As with Int3, Gleevec treatment appears to destabilize the c-Myc protein but not mRNA. These results indicate that Gleevec could be a potential therapeutic drug for patients bearing Notch4 and/or c-Myc positive breast carcinomas.
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Affiliation(s)
- Robert Callahan
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Barry A Chestnut
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Ahmed Raafat
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20814, USA
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Klauzinska M, McCurdy D, Rangel MC, Vaidyanath A, Castro NP, Shen MM, Gonzales M, Bertolette D, Bianco C, Callahan R, Salomon DS, Raafat A. Cripto-1 ablation disrupts alveolar development in the mouse mammary gland through a progesterone receptor-mediated pathway. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2907-22. [PMID: 26429739 DOI: 10.1016/j.ajpath.2015.07.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/24/2015] [Accepted: 07/28/2015] [Indexed: 01/08/2023]
Abstract
Cripto-1, a member of the epidermal growth factor-Cripto-1/FRL-1/Cryptic family, is critical for early embryonic development. Together with its ligand Nodal, Cripto-1 has been found to be associated with the undifferentiated status of mouse and human embryonic stem cells. Several studies have clearly shown that Cripto-1 is involved in regulating branching morphogenesis and epithelial-mesenchymal transition of the mammary gland both in vitro and in vivo and together with the cofactor GRP78 is critical for the maintenance of mammary stem cells ex vivo. Our previous studies showed that mammary-specific overexpression of human Cripto-1 exhibited dramatic morphological alterations in nulliparous mice mammary glands. The present study shows a novel mechanism for Cripto-1 regulation of mammary gland development through direct effects on progesterone receptor expression and pathways regulated by progesterone in the mammary gland. We demonstrate a strict temporal regulation of mouse Cripto-1 (mCripto-1) expression that occurs during mammary gland development and a stage-specific function of mCripto-1 signaling during mammary gland development. Our data suggest that Cripto-1, like the progesterone receptor, is not required for the initial ductal growth but is essential for subsequent side branching and alveologenesis during the initial stages of pregnancy. Dissection of the mechanism by which this occurs indicates that mCripto-1 activates receptor activator NF-κB/receptor activator NF-κB ligand, and NF-κB signaling pathways.
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Affiliation(s)
- Malgorzata Klauzinska
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - David McCurdy
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Maria Cristina Rangel
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Arun Vaidyanath
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Nadia P Castro
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Michael M Shen
- Departments of Medicine Genetics and Development, Urology, and Systems Biology, Columbia University Medical Center, New York, New York
| | - Monica Gonzales
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Daniel Bertolette
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Caterina Bianco
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Robert Callahan
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - David S Salomon
- Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Ahmed Raafat
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
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Klauzinska M, Baljinnyam B, Raafat A, Rodriguez-Canales J, Strizzi L, Greer YE, Rubin JS, Callahan R. Rspo2/Int7 regulates invasiveness and tumorigenic properties of mammary epithelial cells. J Cell Physiol 2012; 227:1960-71. [PMID: 21732367 DOI: 10.1002/jcp.22924] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rspo2 was identified as a novel common integration site (CIS) for the mouse mammary tumor virus (MMTV) in viral induced mouse mammary tumors. Here we show that Rspo2 modulates Wnt signaling in mouse mammary epithelial cells. Co-expression of both genes resulted in an intermediate growth phenotype on plastic and had minor effects on the growth-promoting properties of Wnt1 in soft agar. However, individual Rspo2 and Wnt1 HC11 transfectants as well as the double transfectant were tumorigenic in athymic nude mice, with tumors from each line having distinctive histological characteristics. Rspo2 and Rspo2/Wnt1 tumors contained many spindle cells, consistent with an epithelial-mesenchymal transformation (EMT) phenotype. When Rspo2 and Rspo2/Wnt1 tumor cells were transferred into naïve mice, they exhibited greater metastatic activity than cells derived from Wnt1 tumors. For comparison, C57MG/Wnt1/Rspo2 co-transfectants exhibited invasive properties in three-dimensional (3D) Matrigel cultures that were not seen with cells transfected only with Wnt1 or Rspo2. Use of Dickkopf-1, a specific antagonist of the Wnt/β-catenin pathway, or short hairpin RNA targeting β-catenin expression demonstrated that the invasive activity was not mediated by β-catenin. Our results indicate that Rspo2 and Wnt1 have mutually distinct effects on mammary epithelial cell growth and these effects are context-dependent. While Rspo2 and Wnt1 act synergistically in the β-catenin pathway, other mechanisms are responsible for the invasive properties of stable double transfectants observed in 3D Matrigel cultures.
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Affiliation(s)
- Malgorzata Klauzinska
- Oncogenetics Section, Mammary Biology and Tumorigenesis Laboratory, National Cancer Institute, Bethesda, MD 20892, USA
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Sun Y, Klauzinska M, Lake RJ, Lee JM, Santopietro S, Raafat A, Salomon D, Callahan R, Artavanis-Tsakonas S. Trp53 regulates Notch 4 signaling through Mdm2. J Cell Sci 2011; 124:1067-76. [PMID: 21402876 DOI: 10.1242/jcs.068965] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Notch receptors and their ligands have crucial roles in development and tumorigenesis. We present evidence demonstrating the existence of an antagonistic relationship between Notch 4 and Trp53, which is controlled by the Mdm2-dependent ubiquitylation and degradation of the Notch receptor. We show that this signal-controlling mechanism is mediated by physical interactions between Mdm2 and Notch 4 and suggest the existence of a trimeric complex between Trp53, Notch 4 and Mdm2, which ultimately regulates Notch activity. Functional studies indicate that Trp53 can suppress NICD4-induced anchorage-independent growth in mammary epithelial cells and present evidence showing that Trp53 has a pivotal role in the suppression of Notch-associated tumorigenesis in the mammary gland.
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Affiliation(s)
- Youping Sun
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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Analysis of Brca1-deficient mouse mammary glands reveals reciprocal regulation of Brca1 and c-kit. Oncogene 2010; 30:1597-607. [PMID: 21132007 DOI: 10.1038/onc.2010.538] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Disruption of the breast cancer susceptibility gene Brca1 results in defective lobular-alveolar development in the mammary gland and a predisposition to breast tumourigenesis in humans and in mice. Recent evidence suggests that BRCA1 loss in humans is associated with an expansion of the luminal progenitor cell compartment in the normal breast and tumours with a luminal progenitor-like expression profile. To further investigate the role of BRCA1 in the mammary gland, we examined the consequences of Brca1 loss in mouse mammary epithelial cells in vitro and in vivo. Here, we show that Brca1 loss is associated with defective morphogenesis of SCp2 and HC11 mouse mammary epithelial cell lines and that in the MMTV-Cre Brca1(Co/Co) mouse model of Brca1 loss, there is an accumulation of luminal progenitor (CD61(+)CD29(lo)CD24(+)) cells during pregnancy. By day 1 of lactation, there are marked differences in the expression of 1379 genes, with most significantly altered pathways and networks, including lactation, the immune response and cancer. One of the most differentially expressed genes was the luminal progenitor marker, c-kit. Immunohistochemical analysis revealed that the increase in c-kit levels is associated with an increase in c-kit positivity. Interestingly, an inverse association between Brca1 and c-kit expression was also observed during mammary epithelial differentiation, and small interfering RNA-mediated knockdown of Brca1 resulted in a significant increase in c-kit mRNA levels. We found no evidence that c-kit plays a direct role in regulating differentiation of HC11 cells, suggesting that Brca1-mediated induction of c-kit probably contributes to Brca1-associated tumourigenesis via another cellular process, and that c-kit is likely to be a marker rather than a mediator of defective lobular-alveolar development resulting from Brca1 loss.
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Transforming acidic coiled-coil protein-3 (Tacc3) acts as a negative regulator of Notch signaling through binding to CDC10/Ankyrin repeats. Biochem Biophys Res Commun 2010; 400:606-12. [PMID: 20804727 DOI: 10.1016/j.bbrc.2010.08.111] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 08/25/2010] [Indexed: 11/22/2022]
Abstract
We have identified the transforming acidic coiled-coil protein-3 (Tacc3) as a binding partner for Notch4/Int3 and were able to show that it binds to the intracellular domain (ICD) of all members of the Notch receptor family. Members of the Tacc family reside at the centrosomes and associates with microtubules. Recent studies suggest that Tacc3 also contributes to the regulation of gene transcription. Tacc3 specifically interacts with the Notch4/Int3 CDC10/Ankyrin repeats and to a lesser extent, with residues C-terminal to these repeats in the ICD. Dual label immunofluorescence of mouse mammary tissue shows Tacc3 co-localizes with the Notch3 ICD. Co-immunoprecipitation of endogenous Notch and Tacc3 proteins from NIH3T3 cell extracts, lung and mammary gland confirms that these two proteins interact under physiological conditions. In addition, knock down of Tacc3 in NIH3T3 cells leads to the up-regulation of Hey2, a target gene for Notch signaling. The affinity of Tacc3 binding to Notch4/Int3 ICD is similar to that between Rbpj and Notch4/Int3 ICD. Notch4/Int3 ICD-Tacc3 interaction results in the inhibition of transcription from a Hes1-Luciferase reporter vector in COS-1 cells. The inhibition was reversed in these cells by increasing the levels of Rbpj. Taken together, these results suggest that Tacc3 is a negative regulator of the Notch signaling pathway.
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Abstract
In recent years a substantial body of evidence derived from not only preclinical but also clinical studies has accumulated in support of Notch signaling playing important oncogenic roles in several types of cancer. The finding that activating Notch mutations are frequently found in patients suffering from acute lymphoblastic leukemia is one of the best examples for a critical role of Notch signaling in cancer, a fact that motivated many researchers and clinicians to study the role of Notch also in solid tumors. Hence Notch signaling has gained increasing attention as a potential therapeutic target. In this book chapter we would like to discuss our current knowledge of Notch signaling within different types of solid cancers as well as advantages and disadvantages of potential new therapies that try to target the oncogenic properties of Notch signaling.
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Affiliation(s)
- Ute Koch
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Institute for Experimental Cancer Research (ISREC), Lausanne, Switzerland
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Diao JS, Zhang X, Xia WS, Zheng Y, Ren J, Wang YM, Gong Z, Xia W, Guo SZ. Aberrant Notch signaling: A potential pathomechanism of vitiligo. Med Hypotheses 2009; 73:70-2. [DOI: 10.1016/j.mehy.2009.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 12/31/2008] [Accepted: 02/02/2009] [Indexed: 12/15/2022]
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Rbpj conditional knockout reveals distinct functions of Notch4/Int3 in mammary gland development and tumorigenesis. Oncogene 2008; 28:219-30. [PMID: 18836481 DOI: 10.1038/onc.2008.379] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transgenic mice expressing the Notch 4 intracellular domain (ICD) (Int3) in the mammary gland have two phenotypes: arrest of mammary alveolar/lobular development and mammary tumorigenesis. Notch4 signaling is mediated primarily through the interaction of Int3 with the transcription repressor/activator Rbpj. We have conditionally ablated the Rbpj gene in the mammary glands of mice expressing whey acidic protein (Wap)-Int3. Interestingly, Rbpj knockout mice (Wap-Cre(+)/Rbpj(-/-)/Wap-Int3) have normal mammary gland development, suggesting that the effect of endogenous Notch signaling on mammary gland development is complete by day 15 of pregnancy. RBP-J heterozygous (Wap-Cre(+)/Rbpj(-/+)/Wap-Int3) and Rbpj control (Rbpj(flox/flox)/Wap-Int3) mice are phenotypically the same as Wap-Int3 mice with respect to mammary gland development and tumorigenesis. In addition, the Wap-Cre(+)/Rbpj(-/-)/Wap-Int3-knockout mice also developed mammary tumors at a frequency similar to Rbpj heterozygous and Wap-Int3 control mice but with a slightly longer latency. Thus, the effect on mammary gland development is dependent on the interaction of the Notch ICD with the transcription repressor/activator Rbpj, and Notch-induced mammary tumor development is independent of this interaction.
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Shan L, Zhang R, Zhang W, Lee E, Sridhar R, Snyderwine EG, Wang PC. Image-based evaluation of the molecular events underlying HC11 mammary epithelial cell differentiation. Anal Biochem 2008; 382:122-8. [PMID: 18722992 DOI: 10.1016/j.ab.2008.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 08/01/2008] [Indexed: 01/27/2023]
Abstract
We have developed an image-based technique for signal pathway analysis, target validation, and compound screening related to mammary epithelial cell differentiation. This technique used the advantages of optical imaging and the HC11-Lux model system. The HC11-Lux cell line is a subclone of HC11 mammary epithelial cells transfected stably with a luciferase construct of the beta-casein gene promoter (p-344/-1betac-Lux). The promoter activity was imaged optically in real time following lactogenic induction. The imaging signal intensity was closely correlated with that measured using a luminometer following protein extraction (R=0.99, P<0.0001) and consistent with the messenger RNA (mRNA) level of the endogenous beta -casein gene. Using this technique, we examined the roles of JAK2/Stat5A, Raf-1/MEK/MAKP, and PI3K/Akt signal pathways with respect to differentiation. The imaging studies showed that treatment of the cells with epidermal growth factor (EGF), AG490 (JAK2-specific inhibitor), and LY294002 (PI3K-specific inhibitor) blocked lactogenic differentiation in a dose-dependent manner. PD98059 (MEK-specific inhibitor) could reverse EGF-mediated differentiation arrest. These results indicate that these pathways are essential in cell differentiation. This simple, sensitive, and reproducible technique permits visualization and real-time evaluation of the molecular events related to milk protein production. It can be adopted for high-throughput screening of small molecules for their effects on mammary epithelial cell growth, differentiation, and carcinogenesis.
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Affiliation(s)
- Liang Shan
- Department of Radiology, Howard University, Washington, DC 20060, USA
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Le Gall M, De Mattei C, Giniger E. Molecular separation of two signaling pathways for the receptor, Notch. Dev Biol 2007; 313:556-67. [PMID: 18062953 DOI: 10.1016/j.ydbio.2007.10.030] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 10/18/2007] [Accepted: 10/23/2007] [Indexed: 10/22/2022]
Abstract
Notch is required for many aspects of cell fate specification and morphogenesis during development, including neurogenesis and axon guidance. We here provide genetic and biochemical evidence that Notch directs axon growth and guidance in Drosophila via a "non-canonical", i.e. non-Su(H)-mediated, signaling pathway, characterized by association with the adaptor protein, Disabled, and Trio, an accessory factor of the Abl tyrosine kinase. We find that forms of Notch lacking the binding sites for its canonical effector, Su(H), are nearly inactive for the cell fate function of the receptor, but largely or fully active in axon patterning. Conversely, deletion from Notch of the binding site for Disabled impairs its action in axon patterning without disturbing cell fate control. Finally, we show by co-immunoprecipitation that Notch protein is physically associated in vivo with both Disabled and Trio. Together, these data provide evidence for an alternate Notch signaling pathway that mediates a postmitotic, morphogenetic function of the receptor.
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Affiliation(s)
- Maude Le Gall
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bldg. 37, Rm. 1016, 37 Convent Drive, Bethesda, MD 20892, USA
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