title: Knock-in of oncogenic Kras does not transform mouse somatic cells but triggers a transcriptional response that classifies human cancers.
abstract: KRAS mutations are present at a high frequency in human cancers. The development of therapies targeting mutated KRAS requires cellular and animal preclinical models. We exploited adeno-associated virus-mediated homologous recombination to insert the Kras G12D allele in the genome of mouse somatic cells. Heterozygous mutant cells displayed a constitutively active Kras protein, marked morphologic changes, increased proliferation and motility but were not transformed. On the contrary, mouse cells in which we overexpressed the corresponding Kras cDNA were readily transformed. The levels of Kras activation in knock-in cells were comparable with those present in human cancer cells carrying the corresponding mutation. Kras-mutated cells were compared with their wild-type counterparts by gene expression profiling, leading to the definition of a "mutated Kras-KI signature" of 345 genes. This signature was capable of classifying mouse and human cancers according to their KRAS mutational status, with an accuracy similar to or better than published Ras signatures. The isogenic cells that we have developed recapitulate the oncogenic activation of KRAS occurring in cancer and represent new models for studying Kras-mediated transformation. Our results have implications for the identification of human tumors in which the oncogenic KRAS transcriptional response is activated and suggest new strategies to build mouse models of tumor progression.
authors: Laboratory of Molecular Genetics and Laboratory of Functional Genomics, The Oncogenomics Center, Institute for Cancer Research and Treatment (IRCC), University of Turin Medical School, Candiolo, Turin, Italy.
authors: Sabrina
authors: S
authors: Arena
authors: Claudio
authors: C
authors: Isella
authors: Miriam
authors: M
authors: Martini
authors: Ario
authors: A
authors: de Marco
authors: Enzo
authors: E
authors: Medico
authors: Alberto
authors: A
authors: Bardelli
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000473:pathology; D000229:Dependovirus / Q000235:genetics; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000473:pathology / Q000502:physiology*; D008114:Liver Neoplasms, Experimental / Q000235:genetics* / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D017354:Point Mutation; D013234:Stem Cells / Q000473:pathology / Q000502:physiology; D015533:Transcriptional Activation