Figure 3. Activation of PKA pathway upregulates the protein level of Nm23-H1/2.

(A) HEK293 cells were serum-starved overnight, followed by vehicle or forskolin (0.5, 1, 5, 25, or 50 μM) treatment for 24 h. Cell lysates were immunoblotted for detecting Nm23-H1/2, CREB and phosphorylated CREB. (B) HEK293 cells were treated as in A except forskolin was replaced by isoproterenol (ISO; 0.5, 1, 5, 10, or 50 μM) for 24 h. (C) HEK293 cells were serum-starved overnight, followed by 1 μM forskolin treatment for different periods of time. (D) HEK293 cells were treated as in A except forskolin was replaced by Sp-cAMP (10, 50 μM) or Bt₂cAMP (10, 50 μM). (E) Same as in A except forskolin was replaced by 007-AM (0.5, 1, 5, 10, or 50 μM). Numerical values shown above the immunoreactive bands represent relative intensities of Nm23-H1/2 as a ratio of the basal level (vehicle-treated set as 1.0); variations within control groups are <10%. *Forskolin and ISO significantly upregulated the protein level of Nm23-H1/2 as compared to vehicle treatment (P < 0.05). Data shown represents the mean ± S.E from three independent sets; two other sets yielded similar results.