His-tagged Hsp90α N-terminal domain protein (N-Hsp90α-His) is diluted to 2× the final concentration in the assay buffer consisting of 50 mM Hepes, pH 7, 6 mM MgCl₂, 20 mM KCl and 0.1% BSA. The Hsp90 is dispensed into 96 well polypropylene plates at 50 μL per well. In a separate polypropylene plate, test compounds (NVP-HSP990) are diluted to 40× their final concentration in 100% DMSO. Serial dilutions in DMSO are made in 3-fold increments. 2.5 μL of diluted compounds are transferred to the 50 μL of Hsp90 and mixed. Background wells receive 25 μM (final concentration) radicicol. Biotin-radicicol is diluted into assay buffer at 2× the final concentration and 50 μL are added to the Hsp90/compound plate. DMSO is at a final concentration of 2.5%. Samples are incubated at room temperature for 2 hours before 50 μL are transferred to NeutrAvidin-coated plates. Plates are incubated 1 hour, washed 3× with DELFIA wash buffer (5 mM Tris, pH 7.5, 0.1% Tween 20, 0.1% sodium azide, 0.9% NaCl), and then 50 μL per well of 3 nM Eu-anti-His diluted into DELFIA assay buffer are added. The plates are next incubated 2 hours at room temperature, washed 4×, and then 50 μL enhancement solution are added. Plates are gently shaken for 7-10 minutes before reading in a VICTOR2 instrument^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

GTL-16 Cells (1 × 10³) are plated into 96 well tissue culture plates and cultured at 37°C, 5% CO₂. Serially diluted compounds (NVP-HSP990) are added to the cells and are incubated for 72 hrs. at 37°C, 5% CO₂. Cell proliferation is determined using Cell Viability assay^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Human tumor xenograft models GTL-16, NCI-H1975, BT474, and MV4;11 are implanted subcutaneously with 50% Matrigel in nude or severe combined immunodeficient mice. Mice are randomized into cohorts (10 mice/group for efficacy) when tumors reach 200 to 500 mm³. NVP-HSP990 is administered orally in a vehicle of 100% polyethylene glycol (PEG400). Tumor caliper measurements are converted into tumor volumes using the formula: [length × (width)²]/2. Relative tumor inhibition is calculated as %T/C = 100 × dT/dC, where, dT or dC = difference of mean tumor volume of drug treatment (T) or vehicle (C) on the final day of the study and the randomization volume. Statistical comparisons are conducted using a one-way ANOVA, followed by the Dunn or Tukey post hoc test. Differences are statistically significant at P < 0.05^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Menezes DL, et al. The novel oral Hsp90 inhibitor NVP-HSP990 exhibits potent and broad-spectrum antitumor activities in vitro and in vivo. Mol Cancer Ther. 2012 Mar;11(3):730-9.  [Content Brief]

  [2]. McBride CM, et al. Design, structure-activity relationship, and in vivo characterization of the development candidate NVP-HSP990. J Med Chem. 2014 Nov 13;57(21):9124-9.  [Content Brief]

  [3]. Lamottke B, et al. The novel, orally bioavailable HSP90 inhibitor NVP-HSP990 induces cell cycle arrest and apoptosis in multiple myeloma cells and acts synergistically with melphalan by increased cleavage of caspases. Eur J Haematol. 2012 May;88(5):406-15.  [Content Brief]