AP-III-a4 (ENOblock) (ENOblock) is the first nonsubstrate analogue inhibitor of enolase with IC50 of 0.576 μM.

Enolase:0.576 μM

AP-III-a4 induces glucose uptake and inhibits phosphoenolpyruvate carboxykinase (PEPCK) expression in Huh7 hepatocytes and HEK kidney cells. AP-III-a4 induces cell death under hypoxia, and inhibits cancer cell migration and invasion by down-regulation of AKT and Bcl-xL expression in HCT116 cells.

AP-III-a4 (10 μM) inhibits cancer cell migration and invasion processes in HCT116-xenotransplanted zebrafish tumor model. In vivo, AP-III-a4 (10 μM) also inhibits adipogenesis and foam cell formation, and causes downregulation of PEPCK expression and induction of glucose uptake.

Enolase activity assay is in the 2.0 mM MgSO4 and 400 mM KCl in the absence or presence of ENOblock or NaF, at 37°C by incubating pure enolase (3–9 U) in a buffer containing 50 mM imidazole-HCl (pH 6.8). The reaction is initiated by adding 1 μmol of 2-phospho-D-glycerate, and the OD is measured after 10 min of reaction time with a spectrophometer at 240 nm.

HCT116 cells(3 x 10E5) are seeded in a 6 well plate. 24 h later, cells are treated with AP-III-a4 (5 μM) for 24hours.

In HCT116-xenotransplanted zebrafish tumor xenograft model, were treated with AP-III-a4 of 10 μM.