title: A novel tumor suppressor network in squamous malignancies.
abstract: The specific ablation of Rb1 gene in stratified epithelia (Rb(F/F);K14cre) promotes proliferation and altered differentiation but is insufficient to produce spontaneous tumors. The pRb relative, p107, compensates some of the functions of pRb in these tissues; however, Rb(F/F);K14cre;p107(-/-) mice die postnatally. Here we show, using an inducible mouse model (Rb(F/F);K14creER(TM)), that p107 exerts specific tumor suppressor functions in the absence of pRb in stratified epithelia. The simultaneous absence of pRb and p107 produces impaired p53 transcriptional functions and reduction of Pten expression, allowing spontaneous squamous carcinoma development. These tumors display significant overlap with human squamous carcinomas, supporting that Rb(F/F);K14creER(TM);p107(-/-) mice might constitute a new model for these malignancies. Remarkably tumor development in vivo is partially alleviated by mTOR inhibition. These data demonstrate the existence of a previously unreported functional connection between pRb, Pten and p53 tumor suppressors, through p107, of a particular relevance in squamous tumor development.
authors.affiliation: Molecular Oncology Unit, Department of Basic Research, CIEMAT (Ed 70A), Ave Complutense 40. 28040 Madrid, Spain.
authors.forename: Clotilde
authors.initials: C
authors.lastname: Costa
authors.forename: Mirentxu
authors.initials: M
authors.lastname: Santos
authors.forename: Carmen
authors.initials: C
authors.lastname: Segrelles
authors.forename: Marta
authors.initials: M
authors.lastname: Dueñas
authors.forename: M Fernanda
authors.initials: MF
authors.lastname: Lara
authors.forename: Xabier
authors.initials: X
authors.lastname: Agirre
authors.forename: Felipe
authors.initials: F
authors.lastname: Prosper
authors.forename: Ramón
authors.initials: R
authors.lastname: García-Escudero
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Paramio
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D053263:Gene Regulatory Networks / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D051379:Mice; D018307:Neoplasms, Squamous Cell / Q000235:genetics / Q000378:metabolism; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism; D050720:Retinoblastoma-Like Protein p107 / Q000235:genetics / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: C489485:Rbl1 protein, mouse; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D016159:Tumor Suppressor Protein p53; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse