Fig. 4.
The effects of octaminomycins A (1) and B (2) on the VEGFR2 signal transduction. Serum-starved HUVECs were pretreated with 1, 2 and/or MG132 (10 μM) for 3 h and then stimulated with VEGF (30 ng/ml) for 5 min. Protein levels were detected by Western blot analysis using specific antibodies and further quantified by densitometry. The level of β-actin was used as an internal control. (A) The effects of 1 and 2 on the VEGFR2 signaling in HUVECs. (B) The effect of MG132 on the protein levels of VEGFR2, AKT and ERK1/2 inhibited by 1 and 2.