In vitro activity: MK-8745 leads to cell cycle arrest at the G2/M phase with accumulation of tetraploid nuclei followed by cell death in non-Hodgkin lymphoma (NHL) cell lines. Treatment with MK-8745 induces p21(waf1/cip1) and CycB1, indicating cell cycle arrest and an increase in the G2/M phase cell population. Following MK-8745 treatment, Aurora-A substrates (TACC3, Eg5 and TPX2) are rapidly degraded following the reduction of phospho-Aurora-A. MK8745 induces apoptotic cell death in a p53-dependent manner when tested in vitro in cell lines of multiple lineages. Exposure of p53 wild-type cells to MK8745 results in the induction of p53 phosphorylation (ser15) and an increase in p53 protein expression. p53-dependent apoptosis by MK8745 is further confirmed in HCT 116 p53(-/-) cells transfected with wild-type p53.

Kinase Assay: MK-8745 is a novel, potent and selective Aurora A inhibitor with IC50 of 0.6 nM, 450-fold more selective for Aurora A over Aurora B.

Cell Assay: When tested with p53-/+ cell lines, MK-8745 treatment induced apoptotic cell death in a p53-dependent manner through inhibiting Aurora A activity. In non-Hodgkin lymphoma (NHL) cell lines, MK-8745 treatment arrested cell cycle in G2/M phase and induced cell death via inhibiting Aurora A kinase. In HCT 116 Puma (-), HCT116 p21 (-), HCT116 Bax(-) and HCT116 Chk2(-) cell lines, MK-8745 treatment induced cell apoptosis with the percent of 25%, 22%, 25%, and 22%, respectively.