Cell experiment:

Briefly, 5 × 103 cells/well are plated in 96-well culture plates. After an overnight incubation, the cells are treated with various concentrations of VER-49009 and VER-49009M (0, 1, 2.5, and 5 μM) for 24 h[3].

Animal experiment:

In some studies, female NCr athymic mice are implanted i.p. with 10 million OVCAR3 ovarian carcinoma cells harvested from donor mice. This tumor mimics late-stage malignant disease. Once tumors are well established, mice are injected i.p. with 4 mg/kg VER-49009 or VER-50589 twice daily over 2 days (four doses total). Tumors are harvested at intervals after the last dose and snap frozen for pharmacodynamic analyses[1].

VER-49009 is a potent and selective inhibitor of HSP90 with IC50 value of 47 nM for HSP90β [1].

Heat shock protein 90 (HSP90) is a chaperone protein that stabilizes proteins against heat stress, assists proteins to fold properly and aids in protein degradation. Also, HSP90 stabilizes proteins required for tumor growth.

VER-49009 is a potent HSP90 inhibitor. VER-49009 inhibited recombinant yeast Hsp90 ATPase activity with IC50 value of 167 nM at 400 μM ATP and inhibited recombinant human HSP90β with IC50 value of 1033 nM in the presence of the activator AHA1. Also, VER-49009 bound to recombinant human HSP90β with Kd value of 78.0 nM. In human cancer cells, VER-49009 exhibited antiproliferative activity with mean GI50 value of 685 nM. In HT29 cells, VER-49009 exhibited extensive glucuronidation and increased glucuronide levels by 230-fold, which were responsible for the resistance. In CH1doxR cells that were resistant to doxorubicin, VER-49009 exhibited similar cellular GI50 value compared with CH1 cells. In HCT116 colon cancer cells, VER-49009 caused G1 and G2-M block [1].

In athymic mice bearing OVCAR3 human ovarian ascites tumors, VER-49009 completely inhibited ERBB2 [1].

Reference:
[1].  Sharp SY, Prodromou C, Boxall K, et al. Inhibition of the heat shock protein 90 molecular chaperone in vitro and in vivo by novel, synthetic, potent resorcinylic pyrazole/isoxazole amide analogues. Mol Cancer Ther, 2007, 6(4): 1198-1211.