EMD534085 is an effective and selective mitotic kinesin-5 inhibitor (IC50: 8 nM).

Kinesin-5:8 nM

EMD 534085 does not inhibit any other tested kinesins at 1 μM or 10 μM concentration, showing selectively over kinesin-5. EMD 534085 binds to the allosteric pocket of kinesin-5 [1]. EMD534085 induces rapid cell death in HL60 during mitotic arrest. Caspase-8, ?9, ?3, ?7 are activated; Parp1 is cleaved; Mcl1 and XIAP are degraded in EMD534085-treated HL60 cells. EMD534085 treated HL60 cells also show significantly accumulated phospho-histone H3 level starting at 6 hrs post thymidine release [2].

In a low dose PK of EMD 534085 in mice, the clearance is 1.8 L/h/kg on average, the volume of distribution is 7.4 L/kg and the half-life around 2.5 h. The bioavailability in high dose experiments (>10 mg/kg) is always above 50% in mice. Intraperitoneal administration of EMD 534085 enables significant systemic exposure in mice leading to a significant tumor growth reduction without toxic side effects [1].

Epithelial cell lines HeLa and MCF7 are synchronized in G2-phase using RO-3306. Cells are treated with 10 μM RO-3306 for 16 hrs, and then are ished and released to either warm growth medium or medium supplemented with 500 nM EMD534085 [2].