The reagent, pharmaceutical formulation, kit, and methods of the invention provides a new approach for treating pancreatic cancers. The invention provides the use of Na.sup.+/K.sup.+-ATPase inhibitors, such as cardiac glycosides (e.g. ouabain and proscillaridin, etc.), either alone or in combination with other standard therapeutic agents (chemo- or radio-therapies, etc.) for treating pancreatic cancers.