Research Papers:

ABSTRACT

Mechanisms by which the Stearoyl-CoA desaturase (SCD1) inhibitor aramchol kills tumor cells have recently been described, demonstrating that enhanced signaling through the AMPK played a key role in the processes regulating cell death. Metformin is an anti-hyperglycemic drug which utilizes AMPK signaling to reduce plasma glucose levels. The primary site of metastatic spread of uveal melanoma (UM) is the liver and aramchol concentrates in the liver compared to plasma and other tissues. Aramchol and metformin interacted to modestly enhance cell death in PDX UM cells, though this was less than that caused by the combination of aramchol and the multi-kinase inhibitor regorafenib. Metformin significantly enhanced killing by aramchol plus regorafenib. Metformin significantly enhanced autophagosome formation and autophagic flux caused by aramchol plus regorafenib. Knock down of Beclin1, ATG5 or LAMP2 reduced autophagosome and autolysosome formation, and tumor cell killing. Knock down of BID further enhanced the protective effect of Beclin1 knock down. Knock down of SCD1 enhanced the percentage of dead cells in vehicle control treated cells but did not alter the abilities of drugs to kill tumor cells. Our data demonstrates that UM cells are killed by treatment with aramchol plus regorafenib plus metformin via enhanced autophagic flux and that this combination may have the potential to control UM tumors that have metastasized to the liver.