5 0. 97 and 7. 1 0. 77 M respectively. In a three dimensional cell migration MG132 proteasome assay, BAECs and HDMECs treated with VEGF showed 2. 8 and 2. 5 fold increase in migration to the lower chamber compared to non treated cells respectively. Cheiradone was found to significantly inhibit VEGF induced BAEC and HDMEC migration with IC50 values of 7. 5 0. 92 and 5. 2 0. 38 M respec tively. Cheiradone had no effect on FGF 2 or EGF stimulated migration in the concentration range used. Cheiradone inhibited VEGF induced EC tube formation To examine the role of Inhibitors,Modulators,Libraries cheiradone on EC differentiation into vascular structures in vitro, tube formation of BAECs and HDMCs on Matrigel was assessed. When these cells were stimulated with VEGF, elongated tube like structures were formed and the process was inhibited in a dose dependent manner by cheiradone.

Cheira done reduced the width and length of VEGF induced HDMEC and BAEC tubes with IC50 values of 6. 0 0. 38 and 7. 7 1. 5 M respectively. No significant effect of cheiradone was seen on non stimulated tube formation. Cheiradone inhibited cell invasion The effect of cheiradone on cell invasion was analysed using a Transwell Boyden chamber system coated Inhibitors,Modulators,Libraries with reconstituted growth factor reduced Matrigel. BAECs or HDMECs were allowed to invade the lower chamber in the presence and absence of VEGF and cheiradone. A sta tistically significant increased in cell invasion was observed in VEGF treated HDMECs and BAECs. Cheiradone showed dose dependent inhibition of VEGF stimulated cell invasion of HDMEC and BAEC with IC50 values of 8. 3 1. 0 and 6. 3 0.

31 M respectively. Cheiradone inhibited cell proliferation The above in vitro data suggests that cheiradone inhibits several steps of angiogenesis in vitro. Therefore, we ana lyzed its effect on in vivo angiogenesis using the CAM assay. After exogenous stimulation of angiogenesis with VEGF165, significant new blood Inhibitors,Modulators,Libraries vessel growth Inhibitors,Modulators,Libraries was observed towards the stimulus after 6 days. There was no significant angiogenic response to cheiradone alone. VEGF165 induced blood vessels formation was completely abolished in the presence of cheiradone. There was no evidence of an inflam matory response with cheiradone alone or in the control. Cytotoxicity study No significant cytotoxicity was found at the tested concen trations of cheiradone, whereas staurosporine induced a noticeable cytotoxic effect in the MTT and immunofluorescence assays.

Inhibitors,Modulators,Libraries Discussion Sesterterpenes are naturally occurring polyisoprene com pounds widely distributed in plants and animals. There is growing interest in these molecules as potential disrupters fairly of protein protein interactions since many protein interfaces are characterised by extended, flat surfaces and a number of small molecules which interfere with pro tein protein binding have been identified.