ARP101, a selective MMP-2 inhibitor, induces autophagy-associated cell death in cancer cells

Autophagy is a catabolic cellular process involving self-digestion and turnover of macromolecules and entire organelles. Autophagy is primarily a protective process in response to cellular stress, but it can be associated with cell death. Genetic evidence also supports Autophagy function as a tumor suppressor mechanism. To identify specific regulators to Autophagy, we screened the Lopac 1280 and the Prestwick chemical libraries using a cell-based screening system with Autophagy marker (green fluorescence protein conjugated LC3 protein (GFP-LC3)). We identified ARP101, a selective matrix metalloproteinase-2 (MMP-2) inhibitor as one of the most potent inducer of Autophagy. ARP101 treatment was highly effective in inducing the formation of autophagosome and conversion of LC3I into LC3II. Moreover, ARP101-induced Autophagy was completely blocked in mouse embryo fibroblasts that lacked Autophagy related gene 5 (ATG5(-/-) MEF). Interestingly, cell death induced by ARP101 was not inhibited by zVAD, a pan Caspase Inhibitor, whereas, it was efficiently suppressed by addition of 3-methyladenine, an Autophagy Inhibitor. These results suggest that the selective MMP-2 Inhibitor, ARP101, induces Autophagy and autophagy-associated cell death.