Spontaneous Squamous Cell Carcinoma Induced by the Somatic Inactivation of Retinoblastoma and Trp53 Tumor Suppressors

• Published in: Cancer research (Chicago, Ill.) Ill.), 2008-02, Vol.68 (3), p.683-692
• Main Authors: MARTINEZ-CRUZ, Ana Belén, SANTOS, Mirentxu, FERNANDA LARA, M, SEGRELLES, Carmen, RUIZ, Sergio, MORAL, Marta, LORZ, Corina, GARCIA-ESCUDERO, Ramon, PARAMIO, Jesus M
• Format: Article
• Language: English
• Subjects: Animals; Antineoplastic agents; Biological and medical sciences; Carcinoma, Squamous Cell - blood supply; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - metabolism; Cell Transformation, Neoplastic - genetics; Gene Expression Regulation, Neoplastic; Gene Silencing; Genes, Retinoblastoma; Genetic Predisposition to Disease; Hair Follicle - pathology; Human papillomavirus; Immunohistochemistry; MAP Kinase Signaling System; Medical sciences; Mice; Neovascularization, Pathologic - genetics; Neovascularization, Pathologic - metabolism; Oncogene Protein v-akt - metabolism; Ophthalmology; Pharmacology. Drug treatments; Retinoblastoma Protein - biosynthesis; Retinoblastoma Protein - deficiency; Retinoblastoma Protein - genetics; Retinopathies; Skin Neoplasms - blood supply; Skin Neoplasms - genetics; Skin Neoplasms - metabolism; Tumor Suppressor Protein p53 - biosynthesis; Tumor Suppressor Protein p53 - deficiency; Tumor Suppressor Protein p53 - genetics; Tumors; Tumors and pseudotumors of the eye, orbit, eyelid, lacrimal apparatus
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/0008-5472.CAN-07-3049

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.