EHop-016 is a specific Rac GTPase inhibitor with IC50 of 1.1 μM for Rac1 in MDA-MB-231 and MDA-MB-435 cells, equally effective inhibition for Rac3.

EHop-016 significantly improves the survival rate of leukemia mice with KIT^D814V^ cells.

In MDA-MB-435 cells, EHop-016 (2-5 μM) inhibits the binding of active VAV2 to the Rac1 (G15A) mutant fusion protein, leading to a reduction in Rac-regulated cellular functions, including the formation of lamellipodia and cell migration. Due to compensatory mechanisms, the inhibition of Rac by EHop-016 results in increased activity of the closely related Rho GTPase RhoA. Additionally, EHop-016 suppresses the viability of MDA-MB-435 cells (IC50: 10 μM). EHop-016 also inhibits the growth induced by KITD814V in cells derived from SM and AML patients.

Rac Activity Assays: Rac activity is determined from lysates of the MDA-MB-435 and MDA-MB-231 human metastatic cancer cell lines (from ATCC). Cancer cells in culture medium (DMEM, 10% FBS, pH 7.5) are treated with vehicle (0.1% DMSO) or varying concentrations of EHop-016 (0–10 μM) for 24 h. Rac1 activity is determined using the G-LISA Rac1 activation assay kit.

MDA-MB-231, MDA-MB-435, or MCF-10A mammary epithelial cells (from ATCC) are incubated in vehicle (0.1% DMSO) or varying concentrations of EHop-016 (0–10 μM) for 24 h. Cell viability is measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell survival and proliferation kit according to the manufacturer's instructions.(Only for Reference)