Copper (II) Ions Activate Ligand-Independent Receptor Tyrosine Kinase (RTK) Signaling Pathway.

Receptor tyrosine kinase (RTK) is activated by its natural ligand, mediating multiple essential biological processes. Copper (II) ions are bioactive ions and are crucial in the regulation of cell signaling pathway. However, the crosstalk between copper (II) ions and RTK-mediated cellular signaling remains unclear. Herein, we reported the effect of copper (II) ions on the ligand-independent RTK cellular signaling pathway. Our results indicate that both EGFR and MET signaling were activated by copper (II) in the absence of the corresponding ligands, EGF and HGF, respectively. Consequently, copper (II) ions initiate two RTK-mediated downstream signal transductions, including AKT and ERK. Moreover, copper (II) significantly increased proliferation and cellular migration. Our study proposes a novel role of copper in RTK-mediated signaling for growth factor-independent cancer cell proliferation and migration, implying that targeting both the copper (II) and growth factor in tumor microenvironments may be necessary for cancer treatment.