Related Experiment Videos
ras gene Amplification and malignant transformation
Abstract:
Morphologic transformation of NIH 3T3 mouse cells occurs upon transfection of these cells with large amounts (greater than or equal to 10 micrograms) of recombinant DNA molecules carrying the normal human H-ras-1 proto-oncogene. We provide experimental evidence indicating that transformation of these NIH 3T3 cells results from the combined effect of multiple copies of the H-ras-1 proto-oncogene rather than from spontaneous mutation of one of the transfected H-ras-1 clones (E. Santos, E.P. Reddy, S. Pulciani, R.J. Feldman, and M. Barbacid, Proc. Natl. Acad. Sci. USA 80:4679-4683, 1983). Levels of H-ras-1 RNA and p21 expression are highly elevated in the NIH 3T3 transformants, and in those cases examined, these levels correlate with the malignant properties of these cells. We have also investigated the presence of amplified ras genes in a variety of human carcinomas. In 75 tumor biopsies, we found amplification of the human K-ras-2 locus in one carcinoma of the lung. These results indicate that ras gene amplification is an alternative pathway by which ras genes may participate in the development of human neoplasia.
Insights
High levels of the human H-ras-1 proto-oncogene in NIH 3T3 cells cause morphologic transformation. Gene amplification of ras genes may also contribute to human cancer development.
Area of Science:
- Molecular Biology
- Oncology
- Cell Biology
Background:
- Proto-oncogenes, such as H-ras-1, play critical roles in cellular regulation.
- Abnormalities in proto-oncogene expression or structure can lead to cellular transformation and cancer.
Purpose of the Study:
- To investigate the role of the human H-ras-1 proto-oncogene in the morphologic transformation of NIH 3T3 mouse cells.
- To explore the potential involvement of ras gene amplification in human carcinomas.
Main Methods:
- Transfection of NIH 3T3 cells with recombinant DNA containing the human H-ras-1 proto-oncogene.
- Analysis of H-ras-1 RNA and p21 protein expression levels in transformed cells.
- Screening of human tumor biopsies for amplification of ras genes, specifically the K-ras-2 locus.
Main Results:
- Transfection with large amounts of the H-ras-1 proto-oncogene induced morphologic transformation in NIH 3T3 cells.
- Elevated H-ras-1 RNA and p21 expression correlated with the malignant properties of the transformed cells.
- Amplification of the human K-ras-2 locus was detected in one out of 75 human lung carcinoma biopsies.
Conclusions:
- The transformation of NIH 3T3 cells is attributed to multiple copies of the H-ras-1 proto-oncogene, not spontaneous mutation.
- Ras gene amplification represents an alternative mechanism by which ras genes can contribute to human neoplasia development.