title: Activated Notch1 expression is associated with angiogenesis in cutaneous melanoma.
abstract: An early event in melanocytic tumor growth is the upregulation of Notch signaling. When an active form of Notch1 is overexpressed in primary human melanocytes, it increases cell growth, survival and invasive properties, promoting melanoma progression. Recent evidence suggested that tumor initiation and growth are driven by a subset of tumor-initiating cells termed cancer stem cells. Notch1 plays a predominant role in the maintenance of melanoblasts, including melanocyte stem cells, by preventing initiation of apoptosis. Moreover, the importance of Notch1 in the regulation of tumor angiogenesis is supported by growing evidence in various cancers. Nestin has been widely used as a marker for melanocyte stem cells as well as an angiogenic marker to evaluate neovascularity of endothelial cells in tumors. To gain an insight into the impact of Notch1 activation on the maintenance of melanocyte stem cells and angiogenesis in melanoma, the expression levels of activated Notch1 and nestin were analyzed by immunohistochemistry in 114 primary cutaneous melanomas and 35 lymph node metastases. Activated Notch1 and nestin expression was also evaluated in four dysplastic melanocytic nevi. This study provides evidence that activated Notch1 is overexpressed in cutaneous melanoma, in tumor cells as well as in microvessel endothelium, and that it can promote tumor angiogenesis. Indeed, the overexpression of activated Notch1 in both tumor and vascular endothelial cells was significantly associated with microvascular density in melanoma samples. Thus, activated Notch1 inhibitors may provide a therapeutic strategy in the treatment of melanoma by blocking tumor-associated vascularization.
authors.affiliation: Section of Cytomorphology, Department of Biomedical Sciences, University of Cagliari, S.S. 554, 09042, Monserrato, CA, Italy, murtas@unica.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Murtas
authors.forename: Franca
authors.initials: F
authors.lastname: Piras
authors.forename: Luigi
authors.initials: L
authors.lastname: Minerba
authors.forename: Cristina
authors.initials: C
authors.lastname: Maxia
authors.forename: Caterina
authors.initials: C
authors.lastname: Ferreli
authors.forename: Paolo
authors.initials: P
authors.lastname: Demurtas
authors.forename: Simone
authors.initials: S
authors.lastname: Lai
authors.forename: Ester
authors.initials: E
authors.lastname: Mura
authors.forename: Michela
authors.initials: M
authors.lastname: Corrias
authors.forename: Paola
authors.initials: P
authors.lastname: Sirigu
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Perra
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008853:Microscopy; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology; D009389:Neovascularization, Pathologic; D064231:Nestin / Q000032:analysis; D051881:Receptor, Notch1 / Q000032:analysis*; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: C497761:NOTCH1 protein, human; D064231:Nestin; D051881:Receptor, Notch1