Fig. 4.
Stimulation of A2B receptor-linked signaling pathways increases VEGF secretion and JunB protein levels. (A) VEGF release from HMEC-1 cells incubated in the absence (basal) or presence of 10 μM NECA, 1 μM CGS 21680, 1 μM forskolin, or 10 nM PMA for 6 hours. Values are expressed as mean ± S.E.M. (n = 6). Asterisks indicate significant difference (**P < 0.01, one-way ANOVA with Dunnett’s post test) and ns indicates nonsignificant difference compared with basal levels. (B) Western blot analysis of JunB protein levels in HMEC-1 cells incubated in the absence (basal) or presence 10 μM NECA, 1 μM CGS 21680, 1 μM forskolin, or 10 nM PMA for 3 hours. Arrows indicate positions of JunB and β-actin, the latter used as a loading control. A representative blot of three experiments is shown. (C) Graphic representation of data shown in B quantified by densitometry and expressed as relative density of JunB bands normalized to corresponding β-actin bands.