Neoplastic transformation of a human kidney epithelial cell line transfected with V‐HA‐ras oncogene

We have recently shown that normal human kidney epithelial (NHKE) cells were immortalized by treatment with Ni(II) alone. In the present study the immortalized human kidney cell line (IHKE) was transfected with a plasmid construct containing the v-Ha-ras oncogene (pZipras). After transfection, the cell lines formed tumors in athymic nude mice, whereas the ZipNeoSV(X)-transfected IHKE control cultures formed no tumors. Tumor cell lines (THKE) were established from the tumors in nude mice. These cells appear to be of human epithelial origin and express high levels of Ha-ras transcript. Karyotypic analysis was performed. The cell lines were tri-, tetra- or pentaploid. A consistent finding in the IHKE, IHKZE and THKE cells was increased numbers of chromosomes 17 and 7p+. Some marker chromosomes were identical in the IHKE and THKE cell lines, underlining their common origin and their possible importance in the carcinogenic process. This shows that the combined action of a chemical carcinogen [i.e., Ni(II)] and v-Ha-ras oncogene resulted in fully transformed human kidney epithelial cells, consistent with a step-wise progression of human epithelial cell transformation.