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. 1999 Dec 7;96(25):14523-8.
doi: 10.1073/pnas.96.25.14523.

STEAP: a prostate-specific cell-surface antigen highly expressed in human prostate tumors

R S Hubert  1 , I Vivanco, E Chen, S Rastegar, K Leong, S C Mitchell, R Madraswala, Y Zhou, J Kuo, A B Raitano, A Jakobovits, D C Saffran, D E Afar
Affiliations

STEAP: a prostate-specific cell-surface antigen highly expressed in human prostate tumors

R S Hubert et al. Proc Natl Acad Sci U S A. .

Abstract

In search of novel genes expressed in metastatic prostate cancer, we subtracted cDNA isolated from benign prostatic hypertrophic tissue from cDNA isolated from a prostate cancer xenograft model that mimics advanced disease. One novel gene that is highly expressed in advanced prostate cancer encodes a 339-amino acid protein with six potential membrane-spanning regions flanked by hydrophilic amino- and carboxyl-terminal domains. This structure suggests a potential function as a channel or transporter protein. This gene, named STEAP for six-transmembrane epithelial antigen of the prostate, is expressed predominantly in human prostate tissue and is up-regulated in multiple cancer cell lines, including prostate, bladder, colon, ovarian, and Ewing sarcoma. Immunohistochemical analysis of clinical specimens demonstrates significant STEAP 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, nonprostate human tissues, except for bladder tissue, which expressed low levels of STEAP at the cell membrane. Protein analysis located STEAP at the cell surface of prostate-cancer cell lines. Our results support STEAP as a cell-surface tumor-antigen target for prostate cancer therapy and diagnostic imaging.

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Figures

Figure 1
Figure 1
Amino acid sequence of human STEAP. Boxed regions correspond to the putative membrane-spanning domains. The amino and carboxyl termini are both predicted to be intracellular. The amino-terminal peptide used for generating the anti-STEAP antibody is underlined.
Figure 2
Figure 2
Gene expression of STEAP in tissues and cell lines. (A) Human normal tissue filters contain 2 μg of mRNA per lane. Lanes are: 1, heart; 2, brain; 3, placenta; 4, lung; 5, liver; 6, skeletal muscle; 7, kidney; 8, pancreas; 9, spleen; 10, thymus; 11, prostate; 12, testis; 13, ovary; 14, small intestine; 15, colon; and 16, peripheral blood leukocytes. (B) Xenograft and cell-line filters were prepared with 10 μg of total RNA per lane. Lanes are: 1, primary prostate epithelial cells; 2, prostate; 3, LAPC-4 AD; 4, LAPC-4 AI; 5, LAPC-9 AD; 6, LAPC-9 AI; 7, LNCaP; 8, PC-3; 9, DU145; 10, PANC-1; 11, BxPC-3; 12, HPAC; 13, Capan-1; 14, CACO-2; 15, LOVO; 16, T84; 17, COLO-205; 18, KCL-22 (acute lymphocytic leukemia, ALL); 19, HT1197; 20, SCABER; 21, UM-UC-3; 22, TCCSUP; 23, J82; 24, 5637; 25, RD-ES (Ewing sarcoma, EWS); 26, CAMA-1; 27, DU4475; 28, MCF-7; 29, MDA-MB-435s; 30, NTERA-2; 31, NCCIT; 32, TERA-1; 33, TERA-2; 34, A431; 35, HeLa; 36, OV-1063; 37, PA-1; 38, SW 626; and 39, CAOV-3. The blots were probed by using an SSH-derived gene fragment. All RNA samples were normalized by ethidium bromide staining and subsequent analysis with a β-actin probe.
Figure 3
Figure 3
Analysis of STEAP protein expression in cell lines and tissues. Western blots of cell lysates were prepared from xenografts, and cell lines were probed with anti-STEAP antibodies. The samples were normalized with anti-Grb-2 probing of the Western blots (data not shown).
Figure 4
Figure 4
Immunohistochemical analysis of patient samples with anti-STEAP antibodies. Samples include: LNCaP cells probed in the presence of amino-terminal STEAP peptide 1 (a), LNCaP plus nonspecific peptide 2 (b), normal prostate tissue (c), grade 3 prostate carcinoma (d), grade 4 prostate carcinoma (e), LAPC-9 AD xenograft (f), normal bladder (g), and normal colon (h). (×400.)
Figure 5
Figure 5
Cell-surface biotinylation of STEAP in transfected cells and in cancer cell lines. (A) Cell-surface biotinylation of 293T cells transfected with vector alone or with vector containing cDNA encoding 6-His-tagged STEAP. Cell lysates were immunoprecipitated with specific antibodies, transferred to a membrane, and probed with horseradish peroxidase-conjugated streptavidin. Lanes 1–4 and 6 correspond to immunoprecipitates from lysates prepared from STEAP-expressing 293T cells. Lanes 5 and 7 are immunoprecipitates from vector-transfected cells. The immunoprecipitations were performed using the following antibodies: 1, sheep nonimmune; 2, anti-Large T antigen; 3, anti-CD71 (transferrin receptor); 4, anti-His; 5, anti-His; 6, anti-STEAP; and 7, anti-STEAP. (B) Prostate cancer (LNCaP, DU145, PC-3), bladder cancer (UM-UC-3, TCCSUP), and colon cancer (LOVO, COLO) cell lines were either biotinylated (+) or not (−) before lysis. Western blots of streptavidin-purified proteins were probed with anti-STEAP antibodies. Molecular mass markers are indicated in kDa.
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References

    1. Oesterling J E. J Am Med Assoc. 1992;267:2236–2238. - PubMed
    1. van Iersel M P, Witjes W P, de la Rosette J J, Oosterhof G O. Br J Urol. 1995;76:47–53. - PubMed
    1. Jung K, Meyer A, Lein M, Rudolph B, Schnorr D, Loening S A. J Urol. 1998;159:1595–1598. - PubMed
    1. Afrin L B, Stuart R K. J S C Med Assoc. 1994;90:231–236. - PubMed
    1. Horoszewicz J S, Leong S S, Kawinski E, Karr J P, Rosenthal H, Chu T M, Mirand E A, Murphy G P. Cancer Res. 1983;43:1809–1818. - PubMed

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