ELR510444

ELR510444 is a novel microtubule disruptor; inhibits MDA-MB-231 cell proliferation with IC50 of 30.9 nM; not a substrate for the P-glycoprotein drug transporter and retains activity in βIII-tubulin-overexpressing cell lines. IC50 value: 30.9 nM (MDA-MB-231 cell) [1] Target: Microtubule disruptor ELR510444 is not a substrate for the P-glycoprotein drug transporter and retains activity in βIII-tubulin-overexpressing cell lines, suggesting that it circumvents both clinically relevant mechanisms of drug resistance to this class of agents. ELR510444 also shows potent antitumor activity in the MDA-MB-231 xenograft model with at least a 2-fold therapeutic window. Studies in tumor endothelial cells show that a low concentration of ELR510444 (30 nM) rapidly alters endothelial cell shape, similar to the effect of the vascular disrupting agent combretastatin A4. ELR510444 is a novel microtubule-disrupting agent with potential antivascular effects and in vivo antitumor efficacy [1]. ELR510444 decreased HIF-1α and HIF-2α levels, reduced RCC cell viability and clonogenic survival, and induced apoptosis. VHL-deficient RCC cells were more sensitive to ELR510444-mediated apoptosis and restoration of VHL promoted drug resistance. Higher concentrations of ELR51044 promoted apoptosis independently of VHL status, possibly due to the microtubule destabilizing properties of this agent. ELR510444 significantly reduced tumor burden in the 786-O and A498 RCC xenograft models [2].