Disclosed is the use of a cardiac glycoside to decrease or inhibit the secretion of proinflammatory mediators in the treatment of disease conditions characterized by elevated levels of the proinflammatory mediator. The cardiac glycoside is administered to a mammalian subject in need of such treatment, and dosage is adjusted to the mass of the recipient and the need of the recipient to reduce or inhibit the level of the proinflammatory mediator. The proinflammatory mediators suppressed by the invention include IL-8, IL-6, TNFalpha, ICAM-1, IFNgamma, IL-1-beta, MCP-1, MIP-2, and/or epithelial-mesenchymal-transition (EMT). The cardiac glycoside, digitoxin or oleandrin, can be formulated for administration by injection or as an aerosol administered to the respiratory tract or by being ingested, or as nose drops or nasal spray. According to one use, the digitoxin controls microRNA expression in castration-resistant prostate cancer. The microRNA suppresses IL-8 and IL-6 expression in these cells.
