Another good example of such a strategy is the ‘smart bomb’ for prostate cancer, which combines a sarcolemmal and endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor thapsigargin (which induces apoptosis through the activation of ER stress and Ca2+ entry pathways) with a targeting peptide that is a substrate of the serine/protease prostate-specific antigen (PSA) (Denmeade and Isaacs, 2005). This evidence concerns the gene KLK3 and prostate cancer.