NVP-BEP800 is a fully synthetic, orally bioavailable inhibitor of Hsp90 with IC50 value of 58nM [1].
NVP-BEP800 binds to the N-terminal ATP-binding pocket of Hsp90. In a competitive binding fluorescence polarization assay, NVP-BEP800 inhibits Hsp90β with IC50 value of 58nM. And to other 20 protein kinases, NVP-BEP800 shows a IC50 of >10μM. In BT-474 cells and A375 cells, NVP-BEP800 causes the Hsp90-p23 dissociation and client protein degradation (ErbB2) as well as the reduction of client protein phosphorylation (phospho-Akt). Degradation of these oncogenic client proteins results in tumor cell growth arrest and death. NVP-BEP800 inhibits proliferation of tumor cells with an average GI50 of 245nM. And in 46 primary human tumors including small cell lung, mammary cancer and melanoma, the mean IC50 is 750nM. Additionally, treatment of NVP-BEP800 induces apoptosis in human breast cancer cell lines. The antitumor efficacy of NVP-BEP800 is also observed with a dose of 15 or 30 mg/kg/d in A375 xenograft-bearing mice as well as in BT-474 breast cancer xenografts [1].
References:
[1] Massey AJ, Schoepfer J, Brough PA, Brueggen J, Chène P, Drysdale MJ, Pfaar U, Radimerski T, Ruetz S, Schweitzer A, Wood M, Garcia-Echeverria C, Jensen MR. Preclinical antitumor activity of the orally available heat shock protein 90 inhibitor NVP-BEP800. Mol Cancer Ther. 2010 Apr;9(4):906-19.