Related Experiment Videos
Potentiation of epidermal growth factor receptor-mediated oncogenesis by c-Src: implications for the etiology of
M C Maa1, T H Leu, D J McCarley
1Department of Microbiology and Cancer Center, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
Abstract:
c-Src is a nontransforming tyrosine kinase that participates in signaling events mediated by a variety of polypeptide growth factor receptors, including the epidermal growth factor receptor (EGFR). Overexpression and continual ligand stimulation of the EGFR results in morphological transformation of cells in vitro and tumor development in vivo. Elevated levels of c-Src and the EGFR are found in a variety of human malignancies, raising the question of whether c-Src can functionally cooperate with the EGFR during tumorigenesis. To address this issue, we generated c-Src/EGFR double overexpressors and compared their proliferative and biochemical characteristics to those of single overexpressors and control cells. We found that in cells expressing high levels of receptor, c-Src potentiated DNA synthesis, growth in soft agar, and tumor formation in nude mice. Growth potentiation was associated with the formation of a heterocomplex between c-Src and activated EGFR, the appearance of a distinct tyrosyl phosphorylation on the receptor, and an enhancement of receptor substrate phosphorylation. These findings indicate that c-Src is capable of potentiating receptor-mediated tumorigenesis and suggest that synergism between c-Src and the EGFR may contribute to a more aggressive phenotype in multiple human tumors.
Insights
The tyrosine kinase c-Src potentiates tumor growth by interacting with the epidermal growth factor receptor (EGFR). This interaction enhances cell proliferation and tumor formation, suggesting a role in aggressive human cancers.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- c-Src is a tyrosine kinase involved in signaling pathways of growth factor receptors like EGFR.
- Elevated c-Src and EGFR levels are observed in human malignancies.
- The functional cooperation between c-Src and EGFR in tumorigenesis is not fully understood.
Purpose of the Study:
- To investigate the functional cooperation between c-Src and EGFR in promoting tumorigenesis.
- To elucidate the molecular mechanisms underlying this potential synergy.
Main Methods:
- Generation of cells overexpressing both c-Src and EGFR.
- Comparative analysis of proliferative and biochemical characteristics of single and double overexpressors.
- Assessment of DNA synthesis, soft agar colony formation, and tumor development in vivo.
Main Results:
- c-Src significantly potentiated DNA synthesis, soft agar growth, and tumor formation in mice when EGFR was overexpressed.
- This potentiation was linked to the formation of a c-Src/EGFR heterocomplex.
- Distinct tyrosyl phosphorylation on EGFR and enhanced receptor substrate phosphorylation were observed.
Conclusions:
- c-Src actively potentiates EGFR-mediated tumorigenesis.
- Synergistic interaction between c-Src and EGFR may contribute to aggressive phenotypes in human tumors.
- Targeting this interaction could offer therapeutic strategies for specific cancers.