CYT997: a novel orally active tubulin polymerization inhibitor with potent cytotoxic and vascular disrupting activity in vitro and in vivo.

CYT997 is a wholly synthetic compound that possesses highly potent cytotoxic activity in vitro through inhibition of microtubule polymerization. CYT997 blocks the cell cycle at the G(2)-M boundary, and Western blot analysis indicates an increase in phosphorylated Bcl-2, along with increased expression of cyclin B1. Caspase-3 activation is also observed in cells treated with CYT997 along with the generation of poly(ADP-ribose) polymerase. The compound possesses favorable pharmacokinetic properties, is orally bioavailable, and is efficacious per os in a range of in vivo cancer models, including some refractory to paclitaxel treatment. CYT997 exhibits vascular disrupting activity as measured in vitro by effects on the permeability of human umbilical vein endothelial cell monolayers, and in vivo by effects on tumor blood flow. CYT997 possesses a useful combination of pharmacologic and pharmacokinetic properties and has considerable potential as a novel anticancer agent.

C8c-C15 monoseco-analogues of the phenanthroquinolizidine alkaloids julandine and cryptopleurine exhibiting potent anti-angiogenic properties.

Four enantiomerically pure monoseco-analogues, 5, 7, 9, and 11, of the phenanthroquinolizidine alkaloid julandine (1) and four of congener cryptopleurine (2), viz. compounds 6, 8, 10, and 12, have been prepared and subjected to preliminary biological evaluation. These analogues show dramatically reduced cytotoxicity compared with the parent system 2 but they are, nevertheless, potent anti-angiogenic agents.