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  • 1
    Publication Date: 2015-08-13
    Description: Breast cancer is the most frequent cancer in women and consists of heterogeneous types of tumours that are classified into different histological and molecular subtypes. PIK3CA and P53 (also known as TP53) are the two most frequently mutated genes and are associated with different types of human breast cancers. The cellular origin and the mechanisms leading to PIK3CA-induced tumour heterogeneity remain unknown. Here we used a genetic approach in mice to define the cellular origin of Pik3ca-derived tumours and the impact of mutations in this gene on tumour heterogeneity. Surprisingly, oncogenic Pik3ca(H1047R) mutant expression at physiological levels in basal cells using keratin (K)5-CreER(T2) mice induced the formation of luminal oestrogen receptor (ER)-positive/progesterone receptor (PR)-positive tumours, while its expression in luminal cells using K8-CReER(T2) mice gave rise to luminal ER(+)PR(+) tumours or basal-like ER(-)PR(-) tumours. Concomitant deletion of p53 and expression of Pik3ca(H1047R) accelerated tumour development and induced more aggressive mammary tumours. Interestingly, expression of Pik3ca(H1047R) in unipotent basal cells gave rise to luminal-like cells, while its expression in unipotent luminal cells gave rise to basal-like cells before progressing into invasive tumours. Transcriptional profiling of cells that underwent cell fate transition upon Pik3ca(H1047R) expression in unipotent progenitors demonstrated a profound oncogene-induced reprogramming of these newly formed cells and identified gene signatures characteristic of the different cell fate switches that occur upon Pik3ca(H1047R) expression in basal and luminal cells, which correlated with the cell of origin, tumour type and different clinical outcomes. Altogether our study identifies the cellular origin of Pik3ca-induced tumours and reveals that oncogenic Pik3ca(H1047R) activates a multipotent genetic program in normally lineage-restricted populations at the early stage of tumour initiation, setting the stage for future intratumoural heterogeneity. These results have important implications for our understanding of the mechanisms controlling tumour heterogeneity and the development of new strategies to block PIK3CA breast cancer initiation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Van Keymeulen, Alexandra -- Lee, May Yin -- Ousset, Marielle -- Brohee, Sylvain -- Rorive, Sandrine -- Giraddi, Rajshekhar R -- Wuidart, Aline -- Bouvencourt, Gaelle -- Dubois, Christine -- Salmon, Isabelle -- Sotiriou, Christos -- Phillips, Wayne A -- Blanpain, Cedric -- England -- Nature. 2015 Sep 3;525(7567):119-23. doi: 10.1038/nature14665. Epub 2015 Aug 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universite Libre de Bruxelles, IRIBHM, Brussels B-1070, Belgium. ; Institut Jules Bordet, Universite Libre de Bruxelles, Brussels B-1000, Belgium. ; Department of Pathology, Erasme Hospital, Universite Libre de Bruxelles, Brussels B-1070, Belgium. ; DIAPATH - Center for Microscopy and Molecular Imaging (CMMI), Gosselies B-6041, Belgium. ; Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne 3002, Australia. ; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3002, Australia. ; WELBIO, Universite Libre de Bruxelles, Brussels B-1070, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26266985" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Breast Neoplasms/*genetics/metabolism/*pathology ; Cell Differentiation/genetics ; Cell Division ; Cell Lineage ; Cell Transformation, Neoplastic ; Female ; Genes, p53/genetics ; Humans ; Mammary Neoplasms, Animal/*genetics/metabolism/*pathology ; Mice ; Mutation/genetics ; Neoplasm Invasiveness/genetics ; Phenotype ; Phosphatidylinositol 3-Kinases/*genetics/metabolism ; Receptors, Estrogen/metabolism ; Receptors, Progesterone/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2012-09-04
    Description: The skin interfollicular epidermis (IFE) is the first barrier against the external environment and its maintenance is critical for survival. Two seemingly opposite theories have been proposed to explain IFE homeostasis. One posits that IFE is maintained by long-lived slow-cycling stem cells that give rise to transit-amplifying cell progeny, whereas the other suggests that homeostasis is achieved by a single committed progenitor population that balances stochastic fate. Here we probe the cellular heterogeneity within the IFE using two different inducible Cre recombinase-oestrogen receptor constructs targeting IFE progenitors in mice. Quantitative analysis of clonal fate data and proliferation dynamics demonstrate the existence of two distinct proliferative cell compartments arranged in a hierarchy involving slow-cycling stem cells and committed progenitor cells. After wounding, only stem cells contribute substantially to the repair and long-term regeneration of the tissue, whereas committed progenitor cells make a limited contribution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mascre, Guilhem -- Dekoninck, Sophie -- Drogat, Benjamin -- Youssef, Khalil Kass -- Brohee, Sylvain -- Sotiropoulou, Panagiota A -- Simons, Benjamin D -- Blanpain, Cedric -- 079249/Wellcome Trust/United Kingdom -- 092096/Wellcome Trust/United Kingdom -- England -- Nature. 2012 Sep 13;489(7415):257-62. doi: 10.1038/nature11393.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universite Libre de Bruxelles, IRIBHM, Brussels B-1070, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22940863" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Differentiation ; Cell Division ; Cell Lineage ; Cell Survival ; Clone Cells/cytology/metabolism ; Epidermis/*cytology ; Integrases/genetics/metabolism ; Keratin-14/genetics ; Mice ; Promoter Regions, Genetic/genetics ; Protein Precursors/genetics ; Receptors, Estrogen/genetics/metabolism ; Stem Cells/*cytology/metabolism ; Tail/cytology ; Wound Healing/physiology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2014-06-10
    Description: Cancer stem cells (CSCs) have been reported in various cancers, including in skin squamous-cell carcinoma (SCC). The molecular mechanisms regulating tumour initiation and stemness are still poorly characterized. Here we find that Sox2, a transcription factor expressed in various types of embryonic and adult stem cells, was the most upregulated transcription factor in the CSCs of squamous skin tumours in mice. SOX2 is absent in normal epidermis but begins to be expressed in the vast majority of mouse and human pre-neoplastic skin tumours, and continues to be expressed in a heterogeneous manner in invasive mouse and human SCCs. In contrast to other SCCs, in which SOX2 is frequently genetically amplified, the expression of SOX2 in mouse and human skin SCCs is transcriptionally regulated. Conditional deletion of Sox2 in the mouse epidermis markedly decreases skin tumour formation after chemical-induced carcinogenesis. Using green fluorescent protein (GFP) as a reporter of Sox2 transcriptional expression (SOX2-GFP knock-in mice), we showed that SOX2-expressing cells in invasive SCC are greatly enriched in tumour-propagating cells, which further increase upon serial transplantations. Lineage ablation of SOX2-expressing cells within primary benign and malignant SCCs leads to tumour regression, consistent with the critical role of SOX2-expressing cells in tumour maintenance. Conditional Sox2 deletion in pre-existing skin papilloma and SCC leads to tumour regression and decreases the ability of cancer cells to be propagated upon transplantation into immunodeficient mice, supporting the essential role of SOX2 in regulating CSC functions. Transcriptional profiling of SOX2-GFP-expressing CSCs and of tumour epithelial cells upon Sox2 deletion uncovered a gene network regulated by SOX2 in primary tumour cells in vivo. Chromatin immunoprecipitation identified several direct SOX2 target genes controlling tumour stemness, survival, proliferation, adhesion, invasion and paraneoplastic syndrome. We demonstrate that SOX2, by marking and regulating the functions of skin tumour-initiating cells and CSCs, establishes a continuum between tumour initiation and progression in primary skin tumours.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boumahdi, Soufiane -- Driessens, Gregory -- Lapouge, Gaelle -- Rorive, Sandrine -- Nassar, Dany -- Le Mercier, Marie -- Delatte, Benjamin -- Caauwe, Amelie -- Lenglez, Sandrine -- Nkusi, Erwin -- Brohee, Sylvain -- Salmon, Isabelle -- Dubois, Christine -- del Marmol, Veronique -- Fuks, Francois -- Beck, Benjamin -- Blanpain, Cedric -- England -- Nature. 2014 Jul 10;511(7508):246-50. doi: 10.1038/nature13305. Epub 2014 Jun 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universite Libre de Bruxelles, IRIBHM, Brussels B-1070, Belgium. ; 1] Universite Libre de Bruxelles, IRIBHM, Brussels B-1070, Belgium [2]. ; 1] Department of Pathology, Erasme Hospital, Universite Libre de Bruxelles, Brussels B-1070, Belgium [2] DIAPATH-Center for Microscopy and Molecular Imaging (CMMI), Gosselies B-6041, Belgium. ; Department of Pathology, Erasme Hospital, Universite Libre de Bruxelles, Brussels B-1070, Belgium. ; Laboratory of Cancer Epigenetics, Universite Libre de Bruxelles, Brussels B-1070, Belgium. ; Machine Learning Group, Computer Science Department, Faculte des Sciences, Universite Libre de Bruxelles, Brussels B-1050, Belgium. ; Department of Dermatology, Erasme Hospital, Universite Libre de Bruxelles, Brussels B-1070, Belgium. ; 1] Universite Libre de Bruxelles, IRIBHM, Brussels B-1070, Belgium [2] WELBIO, Universite Libre de Bruxelles, Brussels B-1070, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24909994" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Carcinoma, Squamous Cell/genetics/pathology ; Cell Adhesion/genetics ; Cell Proliferation ; Cell Transformation, Neoplastic/*genetics/metabolism ; Disease Models, Animal ; Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Gene Knockdown Techniques ; Gene Regulatory Networks/genetics ; Mice ; Mice, Inbred Strains ; Neoplastic Stem Cells/*metabolism ; SOXB1 Transcription Factors/genetics/*metabolism ; *Skin Neoplasms/genetics/pathology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2016-09-04
    Description: Evidence is emerging that long noncoding RNAs (lncRNAs) may play a role in cancer development, but this role is not yet clear. We performed a genome-wide transcriptional survey to explore the lncRNA landscape across 995 breast tissue samples. We identified 215 lncRNAs whose genes are aberrantly expressed in breast tumors, as compared to normal samples. Unsupervised hierarchical clustering of breast tumors on the basis of their lncRNAs revealed four breast cancer subgroups that correlate tightly with PAM50-defined mRNA-based subtypes. Using multivariate analysis, we identified no less than 210 lncRNAs prognostic of clinical outcome. By analyzing the coexpression of lncRNA genes and protein-coding genes, we inferred potential functions of the 215 dysregulated lncRNAs. We then associated subtype-specific lncRNAs with key molecular processes involved in cancer. A correlation was observed, on the one hand, between luminal A–specific lncRNAs and the activation of phosphatidylinositol 3-kinase, fibroblast growth factor, and transforming growth factor–β pathways and, on the other hand, between basal-like–specific lncRNAs and the activation of epidermal growth factor receptor (EGFR)–dependent pathways and of the epithelial-to-mesenchymal transition. Finally, we showed that a specific lncRNA, which we called CYTOR, plays a role in breast cancer. We confirmed its predicted functions, showing that it regulates genes involved in the EGFR/mammalian target of rapamycin pathway and is required for cell proliferation, cell migration, and cytoskeleton organization. Overall, our work provides the most comprehensive analyses for lncRNA in breast cancers. Our findings suggest a wide range of biological functions associated with lncRNAs in breast cancer and provide a foundation for functional investigations that could lead to new therapeutic approaches.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 5
    Publication Date: 2008-05-19
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 6
    Publication Date: 2008-05-19
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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