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  • *Signal Transduction  (1)
  • Hematopoiesis and Stem Cells, Transplantation, Myeloid Neoplasia, Lymphoid Neoplasia  (1)
  • IN-VIVO  (1)
  • 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="" 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
    Abstract: To determine the role of vascular endothelial growth factor (Vegf) in embryonic erythroid development we have deleted or overexpressed Vegf specifically in the erythroid lineage using the EpoR-iCre transgenic line in combination with Cre/loxP conditional gain and loss of function Vegf alleles. ROSA26 promoter-based expression of the Vegf(164) isoform in the early erythroid lineage resulted in a differentiation block of primitive erythroid progenitor (EryP) development and a partial block in definitive erythropoiesis between the erythroid burst-forming unit and erythroid colony-forming unit stages. Decreased mRNA expression levels of the key erythroid transcription factor Gata1 were causally linked to this phenotype. Conditional deletion of Vegf within the erythroid lineage was associated with increased Gata1 levels and increased erythroid differentiation. Expression of a ROSA26-based GATA2 transgene rescued Gata1 mRNA levels and target genes and restored erythroid differentiation in our Vegf gain of function model. These results demonstrate that Vegf modulates Gata1 expression levels in vivo and provides new molecular insight into Vegf's ability to modulate erythropoiesis.
    Type of Publication: Journal article published
    PubMed ID: 20554972
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  • 3
    Publication Date: 2018-01-05
    Description: Mixed lineage leukemia (MLL) represents a genetically distinct and aggressive subset of human acute leukemia carrying chromosomal translocations of the MLL gene. These translocations result in oncogenic fusions that mediate aberrant recruitment of the transcription machinery to MLL target genes. The N-terminus of MLL and MLL-fusions form a complex with lens epithelium-derived growth factor (LEDGF/p75; encoded by the PSIP1 gene) and MENIN. This complex contributes to the association of MLL and MLL-fusion multiprotein complexes with the chromatin. Several studies have shown that both MENIN and LEDGF/p75 are required for efficient MLL-fusion–mediated transformation and for the expression of downstream MLL-regulated genes such as HOXA9 and MEIS1 . In light of developing a therapeutic strategy targeting this complex, understanding the function of LEDGF/p75 in normal hematopoiesis is crucial. We generated a conditional Psip1 knockout mouse model in the hematopoietic compartment and examined the effects of LEDGF/p75 depletion in postnatal hematopoiesis and the initiation of MLL leukemogenesis. Psip1 knockout mice were viable but showed several defects in hematopoiesis, reduced colony-forming activity in vitro, decreased expression of Hox genes in the hematopoietic stem cells, and decreased MLL occupancy at MLL target genes. Finally, in vitro and in vivo experiments showed that LEDGF/p75 is dispensable for steady-state hematopoiesis but essential for the initiation of MLL-mediated leukemia. These data corroborate the MLL-LEDGF/p75 interaction as novel target for the treatment of MLL -rearranged leukemia.
    Keywords: Hematopoiesis and Stem Cells, Transplantation, Myeloid Neoplasia, Lymphoid Neoplasia
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
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