(-)-Epothilone B is a microtubule (MT) stabilizing drug and natural macrolide antitumor from myxobacteria Sorangium cellulosum. EpoB has similar biological properties to EpoA. However, EpoB is 10-fold more potent than EpoA against P-glycoprotein-expressing multidrug resistant (MDR) cells (IC50 = 2 nM for MDR CCRF-CEM/VBL100 cells). (-)-Epothilone B is similar to paclitaxel in binding displacement, and a substitution for paclitaxel in dependent cell growth. EpoB causes cell cycle arrest (IC50 = 3.5 nM).
General description
Epothilones has antimitotic properties. It prevents microtubule depolymerization and competitively blocks paclitaxel binding to microtubules. Epothilone B is used to treat metastatic breast cancer (MBC).