Filanesib (ARRY520)

Description: Filanesib (formerly also known as ARRY-520) is a novel, potent and synthetic small molecule inhibitor of kinesin spindle protein (KSP) with IC50 of 6 nM. Kinesin spindle protein (KSP), a microtubule-associated motor protein essential for cell cycle progression, is overexpressed in many cancers and is a potential anti-tumor target. Filanesib blocked cell cycle progression, leading to apoptosis in acute myeloid leukemia cell lines that express high levels of KSP. Knockdown of p53, overexpression of XIAP and mutation in caspase-8 did not significantly affect sensitivity to ARRY-520, suggesting that the response is independent of p53, XIAP and the extrinsic apoptotic pathway. Although ARRY-520 induced mitotic arrest in both HL-60 and Bcl-2-overexpressing HL-60Bcl-2 cells, cell death was blunted in HL-60Bcl-2 cells, suggesting that the apoptotic program is executed through the mitochondrial pathway. Accordingly, inhibition of Bcl-2 by ABT-737 was synergistic with ARRY-520 in HL-60Bcl-2 cells. Furthermore, ARRY-520 increased Bim protein levels prior to caspase activation in HL-60 cells. ARRY-520 significantly inhibited tumor growth of xenografts in SCID mice and inhibited AML blast but not normal colony formation, supporting a critical role for KSP in proliferation of leukemic progenitor cells. These results demonstrate that ARRY-520 potently induces cell cycle block and subsequent death in leukemic cells via the mitochondrial pathway and has the potential to eradicate AML progenitor cells.

References: Leukemia. 2009 Oct; 23(10):1755-62.

Related CAS : 885060-09-3 (free base); 1781834-99-8 (TFA); 885060-08-2 (R-isomer)