Rigosertib

Rigosertib (ON-01910 sodium salt) is a non-ATP-competitive inhibitor of PLK1 with IC50 of 9 nM. Rigosertib (ON-01910) inhibited polo-like kinase1 (Plk1), induced apoptosis in CLL B cells without significant toxicity against T cells or normal B cells. Rigosertib also inhibits several multidrug resistant tumor cell lines, including MES-SA, MES-SA/DX5a, CEM, and CEM/C2a, with IC50 of 50-100 nM. Rigosertib also abrogates the pro-survival effect of follicular dendritic cells on CLL cells and reduces SDF-1-induced migration of leukemic cells. Rigosertib (200 mg/kg) shows inhibition on tumor growth in a mouse xengraft model of BT20 cells in vivo.