Copper (II) Ions Activate Ligand-Independent Receptor Tyrosine Kinase (RTK) Signaling Pathway
Figure 1
Copper (II) promotes RTK activation analogous to the ligand-activated pathway. (a) DU145 cells serum-starved for 24 hours were stimulated with 50 μM copper (II) ion and 99 ng/ml EGF for 10 min, respectively. Copper (II) ion and growth factor on EGFR activation were evaluated by western blotting. (b) The phosphorylation level of EGFR in each experiment was quantified and analyzed. Data are represented as means ± S.D. of triplicate experiments (P<0.05, P<0.001). (c) A549 cells were serum-starved for 24 hours and stimulated with 50 μM copper (II) ion and 50 ng/ml HGF for 10 min, respectively. (d) The phosphorylation level of MET in each experiment was quantified and analyzed. Data are represented as mean ± S.D. of triplicate experiments (P<0.05, P<0.001). (e) A549 cells were serum-starved for 24 hours and pretreated without or with foretinib (100 nM) for 2 h. Then the cells were stimulated with 50 μM copper (II) ion for 10 min and subjected to western blotting analysis. (f) The phosphorylation level of MET in each experiment was quantified and analyzed. Data are represented as mean ± S.D. of triplicate experiments (P<0.05, P<0.001).