title: Spontaneous squamous cell carcinoma induced by the somatic inactivation of retinoblastoma and Trp53 tumor suppressors.
abstract: Squamous cell carcinomas (SCC) represent the most aggressive type of nonmelanoma skin cancer. Although little is known about the causal alterations of SCCs, in organ-transplanted patients the E7 and E6 oncogenes of human papillomavirus, targeting the p53- and pRb-dependent pathways, have been widely involved. Here, we report the functional consequences of the simultaneous elimination of Trp53 and retinoblastoma (Rb) genes in epidermis using Cre-loxP system. Loss of p53, but not pRb, produces spontaneous tumor development, indicating that p53 is the predominant tumor suppressor acting in mouse epidermis. Although the simultaneous inactivation of pRb and p53 does not aggravate the phenotype observed in Rb-deficient epidermis in terms of proliferation and/or differentiation, spontaneous SCC development is severely accelerated in doubly deficient mice. The tumors are aggressive and undifferentiated and display a hair follicle origin. Detailed analysis indicates that the acceleration is mediated by premature activation of the epidermal growth factor receptor/Akt pathway, resulting in increased proliferation in normal and dysplastic hair follicles and augmented tumor angiogenesis. The molecular characteristics of this model provide valuable tools to understand epidermal tumor formation and may ultimately contribute to the development of therapies for the treatment of aggressive squamous cancer.
authors.affiliation: Molecular Oncology Unit, Division of Biomedicine, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Madrid, Spain.
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Martínez-Cruz
authors.forename: Mirentxu
authors.initials: M
authors.lastname: Santos
authors.forename: M Fernanda
authors.initials: MF
authors.lastname: Lara
authors.forename: Carmen
authors.initials: C
authors.lastname: Segrelles
authors.forename: Sergio
authors.initials: S
authors.lastname: Ruiz
authors.forename: Marta
authors.initials: M
authors.lastname: Moral
authors.forename: Corina
authors.initials: C
authors.lastname: Lorz
authors.forename: Ramón
authors.initials: R
authors.lastname: García-Escudero
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Paramio
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D016161:Genes, Retinoblastoma; D020022:Genetic Predisposition to Disease; D018859:Hair Follicle / Q000473:pathology; D007150:Immunohistochemistry; D020935:MAP Kinase Signaling System; D051379:Mice; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism; D051058:Oncogene Protein v-akt / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics*; D012878:Skin Neoplasms / Q000098:blood supply / Q000235:genetics* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics*
chemical_list: D016160:Retinoblastoma Protein; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D051058:Oncogene Protein v-akt