title: Spontaneous transformation of murine epithelial cells requires the early acquisition of specific chromosomal aneuploidies and genomic imbalances.
abstract: Human carcinomas are defined by recurrent chromosomal aneuploidies, which result in a tissue-specific distribution of genomic imbalances. In order to develop models for these genome mutations and to determine their role in tumorigenesis, we generated 45 spontaneously transformed murine cell lines from normal epithelial cells derived from bladder, cervix, colon, kidney, lung, and mammary gland. Phenotypic changes, chromosomal aberrations, centrosome number, and telomerase activity were assayed in control uncultured cells and in three subsequent stages of transformation. Supernumerary centrosomes, binucleate cells, and tetraploidy were observed as early as 48 hr after explantation. In addition, telomerase activity increased throughout progression. Live-cell imaging revealed that failure of cytokinesis, not cell fusion, promoted genome duplication. Spectral karyotyping demonstrated that aneuploidy preceded immortalization, consisting predominantly of whole chromosome losses (4, 9, 12, 13, 16, and Y) and gains (1, 10, 15, and 19). After transformation, focal amplifications of the oncogenes Myc and Mdm2 were frequently detected. Fifty percent of the transformed lines resulted in tumors on injection into immunocompromised mice. The phenotypic and genomic alterations observed in spontaneously transformed murine epithelial cells recapitulated the aberration pattern observed during human carcinogenesis. The dominant aberration of these cell lines was the presence of specific chromosomal aneuploidies. We propose that our newly derived cancer models will be useful tools to dissect the sequential steps of genome mutations during malignant transformation, and also to identify cancer-specific genes, signaling pathways, and the role of chromosomal instability in this process.
authors.affiliation: Genetics Branch, National Cancer Institute, Bethesda, MD 20892, USA. nashh@mail.nih.gov
authors.forename: Hesed M
authors.initials: HM
authors.lastname: Padilla-Nash
authors.forename: Karen
authors.initials: K
authors.lastname: Hathcock
authors.forename: Nicole E
authors.initials: NE
authors.lastname: McNeil
authors.forename: David
authors.initials: D
authors.lastname: Mack
authors.forename: Daniel
authors.initials: D
authors.lastname: Hoeppner
authors.forename: Rea
authors.initials: R
authors.lastname: Ravin
authors.forename: Turid
authors.initials: T
authors.lastname: Knutsen
authors.forename: Raluca
authors.initials: R
authors.lastname: Yonescu
authors.forename: Danny
authors.initials: D
authors.lastname: Wangsa
authors.forename: Kathleen
authors.initials: K
authors.lastname: Dorritie
authors.forename: Linda
authors.initials: L
authors.lastname: Barenboim
authors.forename: Yue
authors.initials: Y
authors.lastname: Hu
authors.forename: Thomas
authors.initials: T
authors.lastname: Ried
mesh_terms: D000782:Aneuploidy; D000818:Animals; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D043171:Chromosomal Instability / Q000235:genetics*; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D005260:Female; D016259:Genes, myc; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D010641:Phenotype; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics
chemical_list: C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2