FIGURE 1.

Knockdown of endogenous VEGF-A down-regulates VEGFR-2 expression and its downstream signaling activation. A and B, HUVECs were treated with control or VEGF-A siRNA. Forty-eight hours after transfection, cells were lysed and analyzed by Western blot. For shRNA, HUVECs or bEnd.3 cells were infected by lentivirus for 24 h, selected by puromycin for 48 h, and lysed. For mRNA analysis, mRNA were extracted and then reverse-transcribed into cDNA. The latter was used for real-time PCR. C and D, siRNA-transfected HUVECs were starved overnight and stressed by VEGF-A¹⁶⁵ at 10 ng/ml for 10 min and then quenched and lysed. E, HUVECs were treated by control or VEGF-A siRNA. Eight hours later, VEGF-A¹⁶⁵ was added into the culture medium, and the cells incubated for 40 h. The cells were then lysed and analyzed by Western blot.