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Resistance of NIH3T3 cells to v-fes transformation induced by a dominant negative H-ras mutant
Y Ogiso1, T Yokoyama, H Watari
1Laboratory of Molecular Genetics, Hokkaido University School of Medicine, Japan.
Abstract:
NIH3T3 cells carrying a dominant negative H-ras mutant 116Y acquired resistance to transformation by some PTK oncogenes, i.e., v-fes, v-abl, and v-fms, but were sensitive to viral ras and serine threonine kinase oncogenes, v-raf and v-mos. One clone, designated 1-20, infected with v-fes (1-20 fes) exhibited flat morphology and anchorage-dependent cell growth, as did noninfected 1-20 cells. The 1-20 fes cells expressed v-fes oncogene and produced transforming viruses, although these levels were much lower than those in NIH3T3 cells infected with v-fes (NIH3T3 fes). v-fes mRNAs in NIH3T3 fes cells rapidly increased after infection, while accumulation of the v-fes transcripts in 1-20 fes cells was significantly prolonged. Total tyrosine phosphorylation in both NIH3T3 fes and 1-20 fes cells was correlated with the amounts of pp110v-fes. A few proteins were phosphorylated only in NIH3T3 fes but not in 1-20 fes cells. These results suggest that the cellular ras is involved in a signaling pathway from pp110v-fes and this signal stimulates v-fes expression. Inhibition of the ras function may down-regulate this pathway and result in resistance to transformation by v-fes.
Insights
Cellular ras function is key to v-fes oncogene transformation. Inhibiting ras signaling confers resistance to v-fes oncogene-induced cell transformation, impacting tyrosine kinase oncogene pathways.
Area of Science:
- Molecular Biology
- Oncology
- Cellular Signaling
Background:
- Dominant-negative H-ras mutants confer resistance to certain oncogenes.
- NIH3T3 cells with H-ras mutant 116Y show differential sensitivity to oncogenes.
Purpose of the Study:
- Investigate the role of cellular ras in v-fes oncogene transformation.
- Determine if ras inhibition affects v-fes expression and transformation.
Main Methods:
- Utilized NIH3T3 cells with dominant-negative H-ras mutant.
- Infected cells with v-fes oncogene and analyzed gene expression and protein phosphorylation.
- Compared transformed and non-transformed cell lines.
Main Results:
- NIH3T3 cells with H-ras mutant 116Y were resistant to v-fes transformation.
- v-fes oncogene expression and tyrosine phosphorylation were altered in resistant cells.
- Cellular ras appears to be involved in a signaling pathway regulating v-fes expression.
Conclusions:
- Cellular ras plays a crucial role in the signaling pathway initiated by pp110v-fes.
- Inhibition of ras function can down-regulate this pathway, leading to resistance against v-fes-mediated transformation.