BI2536 is a potent Plk1 inhibitor with IC50 of 0.83 nM, BI2536 shows 4- and 11-fold greater selectivity against Plk2 and Plk3; BI2536 also is a BRD4 inhibitor(IC50= 25 nM).

BI 2536 blocks the activities of Plk2 and Plk3 to a slightly lesser extent with IC50 of 3.5 nM and 9.0 nM, respectively. In HeLa cells, BI 2536 treatment ranging from 10-100 nM leads to the blocking of the recruitment of γ-tubulin and phosphorylation of Apc6 at mitotic centrosomes, inhibition of cohesin release from chromosome arms, induction of monopolar spindles, as well as a range of other mitotic processes that are known to depend on Plk1. BI 2536 treatment leads to the HeLa cells arrested in G2/M, subsequently a sub-G1 DNA peak indicative of DNA breakdown and apoptosis, and accumulated cleaved PARP p85 fragments in a concentration-dependent manner. BI 2536 inhibits the growth of a panel of 32 human cancer cell lines with EC50 of 2-25 nM, while blocking the proliferation of exponentially growing hTERT-RPE1, human umbilical vein endothelial cells (HUVECs), and normal rat kidney (NRK) cells with EC50 of 12-31 nM.