The six-transmembrane epithelial antigen of prostate (STEAP) protein was identified in advanced prostate cancer. STEAP1 is highly expressed in human prostate cancer and is up-regulated in various cancers, including lung, bladder, colon, ovarian, and Ewing cancers. Immunohistochemical analysis of clinical specimens demonstrates significant STEAP1 expression at the cell–cell junctions of the secretory epithelium of prostate and prostate cancer cells. Little to no staining was detected at the plasma membranes of normal non-prostate human tissues, except for bladder tissue, which expressed low levels of STEAP1 at the cell membrane. Its cell-surface localization, together with its six-transmembrane topology, suggests STEAP1 may function as a channel/transporter protein in cell–cell junctions. Given its increased expression in cancer tissues, STEAP1 could be a promising target for T-cell based or antibody immunotherapy. In prostate cancers, STEAP1-specific Targeting STEAP1 appeared also useful for T-cell based immunotherapy in renal and bladder cancers. Finally, STEAP1 was also described as an attractive target for antibody therapy in multiple solid tumors including prostate, renal and bladder cancers. cytotoxic T lymphocytes (CTLs) were found to inhibit the growth of transplantable prostate tumor cells in murine models. An immunization with recombinant DNA or modified vaccinia virus Ankara vector delivering STEAP1 antigen inhibited prostate cancer progression in a murine subcutaneous syngeneic tumor model.
Moreaux J, et al. STEAP1 is overexpressed in cancers: a promising therapeutic target[J]. Biochemical and biophysical research communications, 2012, 429(3): 148-155.