STEAP (Six Transmembrane Epithelial Antigen of the Prostate)

Prostate cancer is the most frequently diagnosed cancer and is the second leading cause of cancer-related deaths in American men. Although the early serum detection of prostate-specific antigen (PSA) plays important roles in early diagnosis, it may not distinguish prostate cancer from benign diseases. Recently, a novel protein, which contains 339 amino acids, named STEAP (six transmembrane epithelial antigen of the prostate), was identified in advanced prostate cancer. STEAP is unique among the currently known prostate cancer markers because of its putative secondary structure, from which one may predict that it functions as a potential channel protein. STEAP is strongly expressed in advanced prostate cancer and some extent expression in other cancers, such as colon and ovarian cancer cell lines. \n\nThe six-transmembrane epithelial antigen of prostate 1 (STEAP1) was the first member of a family of metalloreductases identified as cell-surface antigens in prostate tissue (1,2). The normal function of STEAP is still uncertain; unlike other members of the STEAP family, \nSTEAP1 does not promote iron or copper reduction or uptake and lacks the FNO-like reductase domain critical for activity (3). However, its expression is highly increased in multiple cancer cell lines, including prostate, bladder, colon, and ovarian cancers. Supporting this is evidence that \nSTEAP1 peptides can be used to stimulate CD8+ T cells from healthy donors, enabling them to recognize STEAP1-positive human tumor cells, suggesting that STEAP1 may a potential target for cancer immunotherapy (4). At least three isoforms of STEAP1 are known to exist. \n\nApplications: \nSuitable for use in ELISA, Western Blot, Immunohistochemistry. Other applications not tested.\n\nRecommended Dilution:\nELISA: 0.1-1.0ug/ml. \nWestern Blot: 0.5-2.0ug/ml. By Western blot, this antibody detects a band of approximately 40kD in A431 cell lysate, which corresponds to the predicted molecular weight of STEAP. \nSample was boiled prior to subject 10%SDS-polyacrylamide gel electrophoresis. \nImmunoprecipitation: 3-5ug/extract from 10e7cells. \nOptimal dilutions to be determined by the researcher.\n\nPositive Control: Human spleen tissue lysate\n\nControl Peptide: S7500P\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, aliquot and add glycerol (40-50%). Freeze at -20 degrees C. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

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SPECIFICATIONS

Catalog Number

S7500

Size

100ug

Applications

ELISA, IHC, WB

Hosts

Rabbit

Reactivities

Hum, Mouse, Rat

Form

Supplied as a liquid in PBS with 0.02% sodium azide.

P Type

Pab

Purity

Purified by immunoaffinity chromatography.

Isotype

IgG

References

1. Hubert RS, Vivanco I, Chen E, et al. STEAP: a prostate- specific cell-surface antigen highly expressed in human prostate tumors. Proc. Natl. Acad. Sci. USA 1999; 96:14523-8. \n2. Ohgami RS, Campagna DR, McDonald A, et al. The Steap proteins are metalloreductases. Blood 2006; 108:1388-94. \n3. Ohgami RS, Campagna DR, Greer EL, et al. Identification of a ferrireductase required for efficient transferrin-dependent iron uptake in erythroid cells. Nat. Genet. 2005; 37:1264-9. \n4. Alves PM, Faure O, Graff-Dubois S, et al. STEAP, a prostate tumor antigen, is a target of human CD8+ T cells. Cancer Immunol. Immunother. 2006; 55:1515-23.

Additional Info

Reacts predominantly with STEAP. Does not cross-react with other STEAP proteins. Species Crossreactivity: human, mouse and rat