| References: |
AT7519 is a multi-CDK inhibitor for CDK1, 2, 4, 6 and 9 with IC50 of 10-210 nM; less potent to CDK3 and little active to CDK7.in vitro: AT7519 is an ATP competitive CDK inhibitor with a Ki value of 38 nM for CDK1. AT7519 is inactive against all non-CDK kinases with the exception of GSK3β (IC50 = 89 nM). AT7519 shows potent antiproliferative activity in a variety of human tumor cell lines with IC50 values ranging from 40 nM for MCF-7 to 940 nM for SW620 consistent with the inhibition of CDK1 and CDK2. AT7519 induces dose-dependent cytotoxicity in multiple myeloma (MM) cell lines with IC50 values ranging from 0.5 to 2 μM at 48 hours, with the most sensitive cell lines being MM.1S (0.5 μM) and U266 (0.5 μM) and the most resistant MM.1R (>2 μM). It does not induce cytotoxicity in peripheral blood mononuclear cells (PBMNC). AT7519 partially overcomes the proliferative advantage conferred by IL6 and IGF-1 as well as the protective effect of bone marrow stromal cells (BMSCs). AT7519 induces rapid dephosphorylation of RNA pol II CTD at serine 2 and serine 5 sites, and leads to the inhibition of transcription, partially contributing to AT7519 induced cytotoxicity of MM cells. AT7519 induces activation of GSK-3β by down-regulating GSK-3β phosphorylation, which also contributes to AT7519 induced apoptosis independent of the inhibition of transcription.
in vivo: A twice daily dosing of AT7519 (9.1 mg/kg) causes tumor regression of both early-stage and advanced-stage s.c. tumors in the HCT116 and HT29 colon cancer xenograft models. AT7519 treatment (15 mg/kg) inhibits tumor growth and prolongs the median overall survival of mice in the human MM xenograft mouse model in association with increased caspase 3 activation. |
