Induction of cancer cell migration by epidermal growth factor is initiated by specific phosphorylation of tyrosine 1248 of c‐erbB‐2 receptor via epidermal growth factor receptor

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Abstract
Induction of tumor cell migration is a key step in invasion and metastasis. Here we report that the epidermal growth factor (EGF)‐induced cell migration of breast cancer cells is attributed to a transient, rather than a sustained, activation of phospholipase C (PLC) ‐γ1 due to c‐erbB‐2 signaling. EGF stimulation of EGF receptor (EGFR) overexpressing cells resulted in long‐term PLC‐γ1 tyrosine phosphorylation and sustained levels of inositol‐1,4,5‐triphosphate (IP3) and diacylglycerol (DAG) producing sinusoidal calcium oscillations. In contrast, c‐erbB‐2/EGFR expressing cells displayed baseline transient calcium oscillations after EGF treatment due to short‐term PLC‐γ1 tyrosine phosphorylation and short‐term IP3 and DAG turnover. A third cell line expressing a point‐mutated c‐erbB‐2 receptor that lacks the autophosphorylation Y1248 was generated to investigate whether the different PLC‐γ1 activation was attributed to this structure. Neither PLC‐γ1 tyrosine phosphorylation nor IP3 and DAG turnover and calcium oscillations were observed in this cell line, indicating the modulation of the PLC‐γ1 activation time course by c‐erbB‐2 signaling. Induction of cell migration was solely observable in the c‐erbB‐2‐positive cell line as proved by the mode of actin reorganization and a cell migration assay, using a 3D‐ collagen lattice. In summary, c‐erbB‐2 up‐regulation switches on the cell migration program by modulating the time course of PLC‐γ1 activation.
Funding Information
  • Fritz-Bender-Stiftung