Transformation of immortalized woodchuck hepatic cell lines with the c-Ha-ras proto-oncogene.
Woodchuck hepatocytes were immortalized with the simian virus 40 T antigen (SV40 T-ag) oncogene and utilized in an oncogenic transformation assay. Transfection of these cell lines with an activated C-Ha-ras oncogene (EJ6.6) resulted in the transformation of cells to a phenotype characterized by anchorage-independent growth in soft agar. Colonies of transformed cells were subcloned and up to 80% were positive for oncoprotein expression detected by immunoblot and Northern blot procedures. When compared with the parental cell lines, ras-transformed derivatives were altered both morphologically and in growth rate. The tumorigenic potential of c-Ha-ras transformed cells was demonstrated in severe combined immunodeficient (SCID) mice. There was a latency period of 1 to 4 weeks before tumors were detectable and a period of 7 weeks was required for tumors to reach a diameter of 1 cm. Histologically, tumors derived from cell lines fully transformed by the SV40 T-ag had the appearance of well-differentiated hepatocellular carcinoma (HCC) while tumors derived from c-Ha-ras transformed cell lines had the appearance of poorly differentiated HCC. The capacity to induce oncogenic transformation events in immortalized woodchuck hepatic cell lines should provide the opportunity to study the cooperative effects of hepadnaviral genes in hepatocarcinogenesis in vitro.
Jacob
J R
JR
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Tennant
B C
BC
D016475:3T3 Cells; D000818:Animals; D000952:Antigens, Polyomavirus Transforming; D002461:Cell Line, Transformed; D011905:Genes, ras; D015151:Immunoblotting; D008099:Liver / Q000166:cytology*; D008392:Marmota; D051379:Mice; D016513:Mice, SCID
D000952:Antigens, Polyomavirus Transforming