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  • 1
    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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  • 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: 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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  • 4
    Abstract: BACKGROUND: The likelihood of recurrence in patients with breast cancer who have HER2-positive tumors is relatively high, although trastuzumab is a remarkably effective drug in this setting. Signal transducer and activator of transcription 3 protein (STAT3), a transcription factor that is persistently tyrosine-705 phosphorylated (pSTAT3) in response to numerous oncogenic signaling pathways, activates downstream proliferative and anti-apoptotic pathways. We hypothesized that pSTAT3 expression in HER2-positive breast cancer will confer trastuzumab resistance. METHODS: We integrated reverse phase protein array (RPPA) and gene expression data from patients with HER2-positive breast cancer treated with trastuzumab in the adjuvant setting. RESULTS: We show that a pSTAT3-associated gene signature (pSTAT3-GS) is able to predict pSTAT3 status in an independent dataset (TCGA; AUC = 0.77, P = 0.02). This suggests that STAT3 induces a characteristic set of gene expression changes in HER2-positive cancers. Tumors characterized as high pSTAT3-GS were associated with trastuzumab resistance (log rank P = 0.049). These results were confirmed using data from the prospective, randomized controlled FinHer study, where the effect was especially prominent in HER2-positive estrogen receptor (ER)-negative tumors (interaction test P = 0.02). Of interest, constitutively activated pSTAT3 tumors were associated with loss of PTEN, elevated IL6, and stromal reactivation. CONCLUSIONS: This study provides compelling evidence for a link between pSTAT3 and trastuzumab resistance in HER2-positive primary breast cancers. Our results suggest that it may be valuable to add agents targeting the STAT3 pathway to trastuzumab for treatment of HER2-positive breast cancer.
    Type of Publication: Journal article published
    PubMed ID: 26234940
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  • 5
    Abstract: Trastuzumab is a remarkably effective therapy for patients with human epidermal growth factor receptor 2 (HER2)--positive breast cancer (BC). However, not all women with high levels of HER2 benefit from trastuzumab. By integrating mRNA and protein expression data from Reverse-Phase Protein Array Analysis (RPPA) in HER2-positive BC, we developed gene expression metagenes that reflect pathway activation levels. Next we assessed the ability of these metagenes to predict resistance to adjuvant trastuzumab using gene expression data from two independent datasets.10 metagenes passed external validation (false discovery rate [fdr] 〈 0.05) and showed biological relevance with their pathway of origin. These metagenes were further screened for their association with trastuzumab resistance. An association with trastuzumab resistance was observed and validated only for the AnnexinA1 metagene (ANXA1). In the randomised phase III Fin-her study, tumours with low levels of the ANXA1 metagene showed a benefit from trastuzumab (multivariate: hazard ratio [HR] for distant recurrence = 0.16[95%CI 0.05-0.5]; p = 0.002; fdr = 0.03), while high expression levels of the ANXA1 metagene were associated with a lack of benefit to trastuzmab (HR = 1.29[95%CI 0.55-3.02]; p = 0.56). The association of ANXA1 with trastuzumab resistance was successfully validated in an independent series of subjects who had received trastuzumab with chemotherapy (Log Rank; p = 0.01).In conclusion, in HER2-positive BC, some proteins are associated with distinct gene expression profiles. Our findings identify the ANXA1metagene as a novel biomarker for trastuzumab resistance.
    Type of Publication: Journal article published
    PubMed ID: 26358523
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