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Suppression of cell growth by ectopic expression of N-cadherin
1Department of Molecular Pathogenesis, Nagoya University School of Medicine, 65-Tsurumai-cho, Showa-Ku, Nagoya 466, Japan.
Abstract:
We found that ectopic expression of N-cadherin in 3Y1 caused tight association of cells and, thereby, substantially suppressed cell growth. N-cadherin expression inhibited neither tyrosine phosphorylation of cellular proteins, GTP uptake onto Ras, nor activation of MAP kinase, suggesting that it does not directly interfere the Ras-MAP kinase pathway. However, co-expression of N-cadherin with dominant negative Ras, S17N Ras, showed synergestic growth inhibitory effect, suggesting that N-cadherin signaling antagonizes the Ras-MAP kinase signaling. In addition, we found that N-cadherin yielded cell-cycle arrest at G0/G1 phase. These results strongly suggest that N-cadherin cell adhesion machinery works as a negative controller of cell cycle in 3Y1 and this growth suppressive function of cadherin is distinct from the epithelial morphogenetic function.
Insights
Ectopic N-cadherin expression in 3Y1 cells suppressed growth by arresting the cell cycle at G0/G1. This function is separate from its role in cell adhesion and antagonizes Ras-MAP kinase signaling.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cell-cell adhesion molecules, such as cadherins, play crucial roles in tissue development and homeostasis.
- The Ras-MAP kinase pathway is a key signaling cascade regulating cell proliferation and differentiation.
Purpose of the Study:
- To investigate the role of N-cadherin in cell growth regulation in 3Y1 cells.
- To determine the relationship between N-cadherin expression and the Ras-MAP kinase signaling pathway.
Main Methods:
- Ectopic expression of N-cadherin in 3Y1 cells.
- Analysis of cell growth, cell cycle progression, protein tyrosine phosphorylation, GTP-Ras uptake, and MAP kinase activation.
- Co-expression studies with dominant-negative Ras (S17N Ras).
Main Results:
- Ectopic N-cadherin expression led to tight cell association and suppressed cell growth.
- N-cadherin did not directly inhibit tyrosine phosphorylation, Ras-GTP uptake, or MAP kinase activation.
- Co-expression with dominant-negative Ras showed synergistic growth inhibition, indicating N-cadherin signaling antagonizes Ras-MAP kinase signaling.
- N-cadherin induced cell-cycle arrest at the G0/G1 phase.
Conclusions:
- N-cadherin functions as a negative regulator of cell cycle progression in 3Y1 cells.
- The growth-suppressive function of N-cadherin is independent of its role in epithelial morphogenesis.
- N-cadherin signaling antagonizes the Ras-MAP kinase pathway, contributing to growth inhibition.