A small-molecule, inhibitor of sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) with potential antineoplastic activity. Upon administration, RX108 inhibits the activity of the Na+/K+-ATPase, which prevents the activation of various signal transduction pathways that play a key role in tumor proliferation. This may lead to cell-cycle arrest, apoptosis, and autophagic cell death. Na+/K+-ATPase is overexpressed in certain tumor types and may serve as a scaffold for the assembly of multiple-protein signaling complexes that regulate cell proliferation and motility. In normal, healthy cells, the Na+/K+-ATPase controls transportation of Na+ and K+ across the cell membrane and is essential for electrochemical gradient maintenance, osmotic balance, and cellular pH.