In vitro activity: Autophinib is a novel and potent autophagy inhibitor, which inhibits starvation-induced or rapamyc induced autophagy. It acts by targeting the lipid kinase VPS34 with IC50 values of 90, 40 and 19 nM, respectively. Autophagy is a critical regulator of cellular homeostasis and metabolism. Interference with this process is considered a new approach for the treatment of disease, in particular cancer and neurological disorders. Therefore, novel small-molecule autophagy modulators such as autophinib are in high demand. Autophinib was identified by means of a phenotypic assay monitoring the formation of autophagy-induced puncta, indicating accumulation of the lipidated cytosolic protein LC3 on the autophagosomal membrane. Target identification and validation revealed that autophinib inhibits autophagy induced by starvation or rapamycin by targeting the lipid kinase VPS34.

Kinase Assay: Autophinib is a potent autophagy inhibitor, which can inhibit autophagy induced by starvation or rapamycin by targeting the lipid kinase VPS34 with IC50s of 90, 40 and 19 nM, respectively. Autophinib inhibits the accumulation of autophagosomes under fed as well as starved conditions, but does not affect the number of autolysosomes. Thus it is not a late stage autophagy inhibitor but an inhibitor of autophagosome formation. Autophinib targets VPS34 but not other lipid kinases, mTOR and TBK1. Autophinib appears to be ATP-competitive, targets VPS34 in cell lysate and induces cellular phenotypes consistent with VPS34 inhibition.

Cell Assay: