Steinberg P, Frank H, Odenthal M, Dienes HP, Seidel A. Role of the Ha-ras gene in the malignant transformation of rat liver oval cells.
Int J Cancer 1997;
71:680-5. [PMID:
9178826 DOI:
10.1002/(sici)1097-0215(19970516)71:4<680::aid-ijc27>3.0.co;2-e]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have shown that the oval cell line OC/CDE 22 can be transformed by the highly carcinogenic fjord-region diol epoxides of benzo[c]phenanthrene. Mutational activation of the ras proto-oncogene family has been proposed to be a critical event in the formation of tumors induced by polycyclic aromatic hydrocarbons. Therefore, we investigated whether in the earlier transformed OC/CDE 22 cells any point mutations were detected in the ras proto-oncogene. The results indicate that the malignant transformation of OC/CDE 22 cells by the 4 stereoisomeric benzo[c]phenanthrene diol epoxides in vitro is independent of activation of the Ha-ras proto-oncogene. In addition, Northern and Western blot analyses revealed no overexpression of the Ha-ras protooncogene in the transformed OC/CDE 22 cell lines. However, transfection of the OC/CDE 22 cells with an activated Ha-ras oncogene malignantly transformed the OC/CDE 22 cells, and the transfected cells served as precursor cells of tumors with a cholangiocellular morphology and phenotype. Our latter finding reinforces the view that OC/CDE 22 cells are committed to the bile duct epithelial cell lineage.
Collapse