Onvansertib (NMS-1286937), an oral, specific Polo-like Kinase 1 (PLK1) inhibitor, is with IC50 of 2 nM. The specificity of NMS-P937 forPLK1 is 5000-fold higher over PLK2/PLK3.

NMS-P937 shows a broad-spectrum antiproliferative activity against different solid tumor, leukemias and lymphomas cell lines. NMS-P937 potently causes a mitotic cell-cycle arrest followed by apoptosis in A2780 cells. [2]

In mice xenografted with human HCT116 colon adenocarcinoma cells, NMS-P937 (90 mg/kg/d i.v. or p.o.) shows a significant tumor growth inhibition. [1] In mice bearing HT29, Colo205 colorectal, or A2780 ovarian xenograft tumors, NMS-P937 inhibits xenograft tumor growth. In addition, NMS-P937, in combination with approved cytotoxic drugs, causes enhanced tumor regression, and prolongs survival of animals. [2]

Kinase profile: The inhibitory activity of putative kinase inhibitors and the potency of selected compounds are determined using a trans-phosphorylation assay. Specific peptide or protein substrates are trans-phosphorylated by their specific serine-threonine or tyrosine kinase, in the presence of ATP traced with 33P-γ-ATP, at optimized buffer and cofactors conditions. At the end of the phosphorylation reaction, more than 98% unlabeled ATP and radioactive ATP is captured by adding an excess of the ion exchange dowex resin; the resin then settles down to the bottom of the reaction plate by gravity. Supernatant, containing the phosphorylated substrate, is subsequently withdrawn and transferred into a counting plate, followed by evaluation by b-counting. Inhibitory potency evaluation for all the tested kinases was performed at 25 °C using a 60 min end-point assay where the concentrations of ATP and substrates are kept equal to 2 x αKm and saturated (>5 x αKm), respectively.

Cells are seeded into 96- or 384-well plates at densities ranging from 10,000 to 30,000/cm2 for adherent and 100,000/mL for nonadherent cells in appropriate medium supplemented with 10% fetal calf serum. After 24 hours, cells were treated in duplicate with serial dilutions of NMS-P937, and 72 hours later, the viable cell number was assessed by the CellTiter-Glo Assay (Promega). IC50 values were calculated with a sigmoidal fitting algorithm (Assay Explorer MDL). Experiments were carried out independently at least twice.(Only for Reference)