H-ras-transformed NRK-52E renal epithelial cells have altered growth, morphology and cytoskeletal structure that correlates with renal cell carcinomain vivo

We studied the effect of the ras oncogene on the growth kinetics, morpholog y, cytoskeletal structure, and tumorigenicity of the widely, used NRK-52E r at kidney epithelial cell line and two H-ras oncogene-transformed cell line s, H/1.2-NRK-52E (H/1.2) and H/6.1-NRK-52E (H/6.1). Population doubling tim es of NRK-52E. H/1.2, and H/6.1 cells were 28, 26, and 24 h, respectively, with the transformed cells reaching higher saturation densities than the pa rent cells. NRK-52E cells had typical epithelial morphology with growth in colonies. H/1.2 and H/6.1 cell colonies were more closely packed, highly co ndensed, and had increased plasma membrane ruffling compared to parent cell colonies. NRK-52E cells showed microfilament, microtubule, and intermediat e filament networks typical of epithelial cells, while H/1.2 and H/6.1 cell s showed altered cytoskeleton architecture, with decreased stress fiber and increased microtubule and intermediate filament staining at the microtubul e organizing center. H/1.2 and H/6.1 cells proliferated in an in vitro soft agar transformation assay, indicating anchorage-independence, and rapidly formed tumors in vivo with characteristics of renal cell carcinoma, includi ng mixed populations of sarcomatoid, granular, and clear cells, H/6.1 cells consistently showed more extensive alterations of growth kinetics, morphol ogy, and cytokeleton than H/1.2 cells, and formed tumors of a more aggressi ve phenotype. These data suggest that analysis of renal cell characteristic s in vitro may have potential in predicting turner behavior in vivo, and si gnificantly contribute to the utility of these cell lines as in vitro model s for examining renal epithelial cell biology and the role of the ras proto -oncogene in signal transduction involving the cytoskeleton.