VER-155008 is a potent Hsp70 family inhibitor with IC50 of 0.5 μM, 2.6 μM, and 2.6 μM in cell-free assays for HSP70, HSC70, and GRP78, respectively, >100-fold selectivity over HSP90.

GRP78:2.6 μM, HSP70:0.5 μM, HSC70:2.6 μM

VER-155008 inhibits the proliferation of human breast and colon cancer cell lines BT474, MB-468, HCT116, and HT29 with GI50s in the range 5.3-14.4 μM, and induces Hsp90 client protein degradation in both HCT116 and BT474 cells.[1] In the 8505C and FRO cells, VER-155008 reduces the cell viability and elevates the percentage of dead cells in a time- and dose- dependent manner.[2] VER-155008 causes a dose-dependent inhibition of cytokine-dependent AML cell proliferation.[3] VER-155008?shows an effective inhibition of cell proliferation in A549 and H1975 cells. [4]

In HCT116 tumor bearing mice, VER-155008 (25 or 40 mg/kg, i.v.) demonstrates rapid metabolism and clearance, along with tumor levels below the predicted pharmacologically active level.[1]

Hsc70, Hsp70 and Grp78 ?uorescence polarisation (FP) assay: The FP assay for Hsp70 is conducted in aqueous buffer consisting of 100 mM Tris pH 7.4, 150 mM KCl and 5 mM CaCl2, in a final assay volume of 100 μl, using 96 well black polystyrene high bind plates with a Fusion plate reader. N6-(6-amino)hexyl-ATP-5-FAM and the in-house protein preparation of GST-HSP70 3-382 have final concentrations in the assay of 20 nM and 400 nM, respectively. Compounds are tested as 10-point IC50s, with a final DMSO concentration of 5%. Assay mixtures are incubated for 3 h prior to reading on the Fusion (ex 485 nm; em 535 nm). The data is fitted using a 4 parameter logistical data model by XLFit 4. The FP assay for Hsc70 and Grp78 is carried out as described for Hsp70 using the same N6 -(6-amino)hexyl-ATP-5-FAM as the FP probe with the following modi?cations. For Hsc70, the protein and probe concentrations are 0.3 μM and 20 nM, respectively with a 30 min incubation at 22℃ while for Grp78, the protein and probe concentrations are 2 μM and 10 nM, respectively with a 2 h incubation at 22℃. The KD for the FAM-ATP probe was 0.24 μM for Hsc70 and 2 μM for Grp78.

All cell lines are grown in DMEM/10% FCS with GlutaMAX-I in a humidified atmosphere of 5% CO2 in air. Cell proliferation is determined using the sulforhodamine B (SRB) assay.(Only for Reference)