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  • 1
    Publication Date: 2011-10-21
    Description: Angiogenesis is critical during tumour initiation and malignant progression. Different strategies aimed at blocking vascular endothelial growth factor (VEGF) and its receptors have been developed to inhibit angiogenesis in cancer patients. It has become increasingly clear that in addition to its effect on angiogenesis, other mechanisms including a direct effect of VEGF on tumour cells may account for the efficiency of VEGF-blockade therapies. Cancer stem cells (CSCs) have been described in various cancers including squamous tumours of the skin. Here we use a mouse model of skin tumours to investigate the impact of the vascular niche and VEGF signalling on controlling the stemness (the ability to self renew and differentiate) of squamous skin tumours during the early stages of tumour progression. We show that CSCs of skin papillomas are localized in a perivascular niche, in the immediate vicinity of endothelial cells. Furthermore, blocking VEGFR2 caused tumour regression not only by decreasing the microvascular density, but also by reducing CSC pool size and impairing CSC renewal properties. Conditional deletion of Vegfa in tumour epithelial cells caused tumours to regress, whereas VEGF overexpression by tumour epithelial cells accelerated tumour growth. In addition to its well-known effect on angiogenesis, VEGF affected skin tumour growth by promoting cancer stemness and symmetric CSC division, leading to CSC expansion. Moreover, deletion of neuropilin-1 (Nrp1), a VEGF co-receptor expressed in cutaneous CSCs, blocked VEGF's ability to promote cancer stemness and renewal. Our results identify a dual role for tumour-cell-derived VEGF in promoting cancer stemness: by stimulating angiogenesis in a paracrine manner, VEGF creates a perivascular niche for CSCs, and by directly affecting CSCs through Nrp1 in an autocrine loop, VEGF stimulates cancer stemness and renewal. Finally, deletion of Nrp1 in normal epidermis prevents skin tumour initiation. These results may have important implications for the prevention and treatment of skin cancers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Beck, Benjamin -- Driessens, Gregory -- Goossens, Steven -- Youssef, Khalil Kass -- Kuchnio, Anna -- Caauwe, Amelie -- Sotiropoulou, Panagiota A -- Loges, Sonja -- Lapouge, Gaelle -- Candi, Aurelie -- Mascre, Guilhem -- Drogat, Benjamin -- Dekoninck, Sophie -- Haigh, Jody J -- Carmeliet, Peter -- Blanpain, Cedric -- England -- Nature. 2011 Oct 19;478(7369):399-403. doi: 10.1038/nature10525.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉IRIBHM, Universite Libre de Bruxelles, 808 route de Lennik, 1070 Brussels, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22012397" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Carcinoma, Squamous Cell/*blood supply/*pathology ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Disease Models, Animal ; Epithelial Cells/cytology ; Gene Deletion ; Gene Expression Regulation, Neoplastic ; Mice ; Neoplastic Stem Cells ; Neuropilin-1/genetics/*metabolism ; *Signal Transduction ; Skin Neoplasms/*blood supply/*pathology ; Vascular Endothelial Growth Factor A/genetics/*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: 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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