title: A novel somatic mouse model to survey tumorigenic potential applied to the Hedgehog pathway.
abstract: We report a novel mouse model for the generation of sporadic tumors and show the efficiency of this approach by surveying Hedgehog (Hh)-related tumors. Up-regulation of the Hh pathway is achieved by conditionally regulated expression of an activated allele of Smoothened (R26-SmoM2) using either sporadic leakage or global postnatal induction of a ubiquitously expressed inducible Cre transgene (CAGGS-CreER). Following postnatal tamoxifen induction, CAGGS-CreER; R26-SmoM2 mice developed tumors with short latency and high penetrance. All mice exhibited rhabdomyosarcoma and basal cell carcinoma; 40% also developed medulloblastoma. In addition, mice showed a novel pancreatic lesion resembling low-grade mucinous cystic neoplasms in humans. In contrast, widespread activation of SmoM2 in the postnatal prostate epithelium results in no detectable morphologic outcome in 12-month-old mice. Comparison of gene expression profiles among diverse tumors identified several signature genes, including components of platelet-derived growth factor and insulin-like growth factor pathways, which may provide a common mechanistic link to the Hh-related malignancies. This experimental model provides a robust tool for exploring the process of Hh-dependent tumorigenesis and the treatment of such tumors. More generally, this approach provides a genetic platform for identifying tumorigenic potential in putative oncogenes and tumor suppressors and for more effective modeling of sporadic cancers in mice.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Junhao
authors.initials: J
authors.lastname: Mao
authors.forename: Keith L
authors.initials: KL
authors.lastname: Ligon
authors.forename: Elena Y
authors.initials: EY
authors.lastname: Rakhlin
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Thayer
authors.forename: Roderick T
authors.initials: RT
authors.lastname: Bronson
authors.forename: David
authors.initials: D
authors.lastname: Rowitch
authors.forename: Andrew P
authors.initials: AP
authors.lastname: McMahon
mesh_terms: D000483:Alleles; D000818:Animals; D002280:Basal Cell Carcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D053823:Hedgehog Proteins / Q000378:metabolism*; D019426:Integrases / Q000235:genetics; D008297:Male; D008527:Medulloblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012208:Rhabdomyosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D053823:Hedgehog Proteins; C045073:Cre recombinase; D019426:Integrases