Functional prostate-specific membrane antigen is enriched in exosomes from prostate cancer cells

Liu,Tiancheng; Mendes,Desiree E.; Berkman,Clifford  E.

doi:10.3892/ijo.2014.2256

Functional prostate-specific membrane antigen is enriched in exosomes from prostate cancer cells

Authors:
- Tiancheng Liu
- Desiree E. Mendes
- Clifford E. Berkman
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Affiliations: Department of Chemistry, Washington State University, Pullman, WA 99164, USA
Published online on: January 10, 2014 https://doi.org/10.3892/ijo.2014.2256
Pages: 918-922

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Abstract

Developing simple and effective approaches to detect tumor markers will be critical for early diagnosis or prognostic evaluation of prostate cancer treatment. Prostate‑specific membrane antigen (PSMA) has been validated as an important tumor marker for prostate cancer progression including angiogenesis and metastasis. As a type II membrane protein, PSMA can be constitutively internalized from the cell surface into endosomes. Early endosomes can fuse with multivesicular bodies (MVB) to form and secrete exosomes (40-100 nm) into the extracellular environment. Herein, we tested whether some of the endosomal PSMA could be transferred to exosomes as an extracellular resource for PSMA. Using PSMA-positive LNCaP cells, the secreted exosomes were collected and isolated from the cultured media. The vesicular structures of exosomes were identified by electron microscopy, and exosomal marker protein CD9 and tumor susceptibility gene (TSG 101) were confirmed by western blot analysis. Our present data demonstrate that PSMA can be enriched in exosomes, exhibiting a higher content of glycosylation and partial proteolysis in comparison to cellular PSMA. An in vitro enzyme assay further confirmed that exosomal PSMA retains functional enzymatic activity. Therefore, our data may suggest a new role for PSMA in prostate cancer progression, and provide opportunities for developing non-invasive approaches for diagnosis or prognosis of prostate cancer.

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1.	Bacich DJ, Pinto JT, Tong WP and Heston WD: Cloning, expression, genomic localization, and enzymatic activities of the mouse homolog of prostate-specific membrane antigen/NAALADase/folate hydrolase. Mamm Genome. 12:117–123. 2001. View Article : Google Scholar
2.	Chang SS, Reuter VE, Heston WD and Gaudin PB: Comparison of anti-prostate-specific membrane antigen antibodies and other immunomarkers in metastatic prostate carcinoma. Urology. 57:1179–1183. 2001. View Article : Google Scholar : PubMed/NCBI
3.	Chang SS, O’Keefe DS, Bacich DJ, Reuter VE, Heston WD and Gaudin PB: Prostate-specific membrane antigen is produced in tumor-associated neovasculature. Clin Cancer Res. 5:2674–2681. 1999.PubMed/NCBI
4.	Liu H, Rajasekaran AK, Moy P, et al: Constitutive and antibody-induced internalization of prostate-specific membrane antigen. Cancer Res. 58:4055–4060. 1998.PubMed/NCBI
5.	Rajasekaran AK, Anilkumar G and Christiansen JJ: Is prostate-specific membrane antigen a multifunctional protein? Am J Physiol Cell Physiol. 288:C975–C981. 2005. View Article : Google Scholar : PubMed/NCBI
6.	Liu T, Wu LY, Kazak M and Berkman CE: Cell-surface labeling and internalization by a fluorescent inhibitor of prostate-specific membrane antigen. Prostate. 68:955–964. 2008. View Article : Google Scholar : PubMed/NCBI
7.	Tagawa ST, Beltran H, Vallabhajosula S, et al: Anti-prostate-specific membrane antigen-based radioimmunotherapy for prostate cancer. Cancer. 116:1075–1083. 2010. View Article : Google Scholar : PubMed/NCBI
8.	Wolf P, Freudenberg N, Buhler P, et al: Three conformational antibodies specific for different PSMA epitopes are promising diagnostic and therapeutic tools for prostate cancer. Prostate. 70:562–569. 2010.PubMed/NCBI
9.	Murphy GP, Greene TG, Tino WT, Boynton AL and Holmes EH: Isolation and characterization of monoclonal antibodies specific for the extracellular domain of prostate specific membrane antigen. J Urol. 160:2396–2401. 1998. View Article : Google Scholar : PubMed/NCBI
10.	Morris MJ, Pandit-Taskar N, Divgi CR, et al: Phase I evaluation of J591 as a vascular targeting agent in progressive solid tumors. Clin Cancer Res. 13:2707–2713. 2007. View Article : Google Scholar : PubMed/NCBI
11.	Milowsky MI, Nanus DM, Kostakoglu L, et al: Vascular targeted therapy with anti-prostate-specific membrane antigen monoclonal antibody J591 in advanced solid tumors. J Clin Oncol. 25:540–547. 2007. View Article : Google Scholar : PubMed/NCBI
12.	Tsukamoto T, Wozniak KM and Slusher BS: Progress in the discovery and development of glutamate carboxypeptidase II inhibitors. Drug Discov Today. 12:767–776. 2007. View Article : Google Scholar : PubMed/NCBI
13.	Kularatne SA, Zhou Z, Yang J, Post CB and Low PS: Design, synthesis, and preclinical evaluation of prostate-specific membrane antigen targeted (99m)Tc-radioimaging agents. Mol Pharm. 6:790–800. 2009. View Article : Google Scholar : PubMed/NCBI
14.	Lapi SE, Wahnishe H, Pham D, et al: Assessment of an 18F-labeled phosphoramidate peptidomimetic as a new prostate-specific membrane antigen-targeted imaging agent for prostate cancer. J Nucl Med. 50:2042–2048. 2009. View Article : Google Scholar : PubMed/NCBI
15.	Cho SY, Gage KL, Mease RC, et al: Biodistribution, tumor detection, and radiation dosimetry of 18F-DCFBC, a low-molecular-weight inhibitor of prostate-specific membrane antigen, in patients with metastatic prostate cancer. J Nucl Med. 53:1883–1891. 2012. View Article : Google Scholar : PubMed/NCBI
16.	Azmi AS, Bao B and Sarkar FH: Exosomes in cancer development, metastasis, and drug resistance: a comprehensive review. Cancer Metastasis Rev. May 25–2013.(Epub ahead of print).
17.	Thery C: Exosomes: secreted vesicles and intercellular communications. F1000 Biol Rep. 3:152011. View Article : Google Scholar : PubMed/NCBI
18.	Thompson CA, Purushothaman A, Ramani VC, Vlodavsky I and Sanderson RD: Heparanase regulates secretion, composition, and function of tumor cell-derived exosomes. J Biol Chem. 288:10093–10099. 2013. View Article : Google Scholar : PubMed/NCBI
19.	Kharaziha P, Ceder S, Li Q and Panaretakis T: Tumor cell-derived exosomes: a message in a bottle. Biochim Biophys Acta. 1826:103–111. 2012.PubMed/NCBI
20.	Liu T, Mendes DE and Berkman CE: From AR to c-Met: Androgen deprivation leads to a signaling pathway switch in prostate cancer cells. Int J Oncol. 43:1125–1130. 2013.PubMed/NCBI
21.	Liu T, Wu LY, Fulton MD, Johnson JM and Berkman CE: Prolonged androgen deprivation leads to downregulation of androgen receptor and prostate-specific membrane antigen in prostate cancer cells. Int J Oncol. 41:2087–2092. 2012.PubMed/NCBI
22.	Liu T, Wu LY and Berkman CE: Prostate-specific membrane antigen-targeted photodynamic therapy induces rapid cytoskeletal disruption. Cancer Lett. 296:106–112. 2010. View Article : Google Scholar : PubMed/NCBI
23.	Liu T, Toriyabe Y and Berkman CE: Purification of prostate-specific membrane antigen using conformational epitope-specific antibody-affinity chromatography. Protein Expr Purif. 49:251–255. 2006. View Article : Google Scholar
24.	Wu LY, Anderson MO, Toriyabe Y, et al: The molecular pruning of a phosphoramidate peptidomimetic inhibitor of prostate-specific membrane antigen. Bioorg Med Chem. 15:7434–7443. 2007. View Article : Google Scholar : PubMed/NCBI
25.	Anderson MO, Wu LY, Santiago NM, et al: Substrate specificity of prostate-specific membrane antigen. Bioorg Med Chem. 15:6678–6686. 2007. View Article : Google Scholar : PubMed/NCBI
26.	Maung J, Mallari JP, Girtsman TA, et al: Probing for a hydrophobic a binding register in prostate-specific membrane antigen with phenylalkylphosphonamidates. Bioorg Med Chem. 12:4969–4979. 2004. View Article : Google Scholar : PubMed/NCBI
27.	Lehmann BD, Paine MS, Brooks AM, et al: Senescence-associated exosome release from human prostate cancer cells. Cancer Res. 68:7864–7871. 2008. View Article : Google Scholar : PubMed/NCBI
28.	Hosseini-Beheshti E, Pham S, Adomat H, Li N and Tomlinson Guns ES: Exosomes as biomarker enriched microvesicles: characterization of exosomal proteins derived from a panel of prostate cell lines with distinct AR phenotypes. Mol Cell Proteomics. 11:863–885. 2012. View Article : Google Scholar
29.	Mitchell PJ, Welton J, Staffurth J, et al: Can urinary exosomes act as treatment response markers in prostate cancer? J Transl Med. 7:42009. View Article : Google Scholar : PubMed/NCBI
30.	Rajasekaran SA, Anilkumar G, Oshima E, et al: A novel cytoplasmic tail MXXXL motif mediates the internalization of prostate-specific membrane antigen. Mol Biol Cell. 14:4835–4845. 2003. View Article : Google Scholar : PubMed/NCBI
31.	Vlassov AV, Magdaleno S, Setterquist R and Conrad R: Exosomes: current knowledge of their composition, biological functions, and diagnostic and therapeutic potentials. Biochim Biophys Acta. 1820:940–948. 2012. View Article : Google Scholar : PubMed/NCBI
32.	Tauro BJ, Greening DW, Mathias RA, et al: Comparison of ultracentrifugation, density gradient separation, and immunoaffinity capture methods for isolating human colon cancer cell line LIM1863-derived exosomes. Methods. 56:293–304. 2012. View Article : Google Scholar
33.	Trzpis M, McLaughlin PM, de Leij LM and Harmsen MC: Epithelial cell adhesion molecule: more than a carcinoma marker and adhesion molecule. Am J Pathol. 171:386–395. 2007. View Article : Google Scholar : PubMed/NCBI
34.	Ghosh A and Heston WD: Tumor target prostate specific membrane antigen (PSMA) and its regulation in prostate cancer. J Cell Biochem. 91:528–539. 2004. View Article : Google Scholar
35.	Wu LY, Liu T, Hopkins MR, Davis WC and Berkman CE: Chemoaffinity capture of pre-targeted prostate cancer cells with magnetic beads. Prostate. 72:1532–1541. 2012. View Article : Google Scholar : PubMed/NCBI