Endogenous oncogenic K-ras(G12D) stimulates proliferation and widespread neoplastic and developmental defects.
Activating mutations in the ras oncogene are not considered sufficient to induce abnormal cellular proliferation in the absence of cooperating oncogenes. We demonstrate that the conditional expression of an endogenous K-ras(G12D) allele in murine embryonic fibroblasts causes enhanced proliferation and partial transformation in the absence of further genetic abnormalities. Interestingly, K-ras(G12D)-expressing fibroblasts demonstrate attenuation and altered regulation of canonical Ras effector signaling pathways. Widespread expression of endogenous K-ras(G12D) is not tolerated during embryonic development, and directed expression in the lung and GI tract induces preneoplastic epithelial hyperplasias. Our results suggest that endogenous oncogenic ras is sufficient to initiate transformation by stimulating proliferation, while further genetic lesions may be necessary for progression to frank malignancy.
Pubmed ID: 15093544 RIS Download
Animals | Cell Aging | Cell Cycle | Cell Division | Cell Transformation, Neoplastic | Congenital Abnormalities | Crosses, Genetic | Cyclin-Dependent Kinase Inhibitor p16 | Embryo, Mammalian | Female | Fibroblasts | Gene Expression Regulation, Developmental | Genes, ras | Integrases | Male | Mice | Mice, Inbred C57BL | Mice, Transgenic | Mutation | Neoplasms | Stem Cells | Tumor Suppressor Protein p14ARF | Tumor Suppressor Protein p53 | Viral Proteins