We have identified the serine protease PRSS3/mesotrypsin as a molecule that is prognostic for prostate cancer systemic progression following prostatectomy, and that is upregulated in metastatic prostate cancer tissue. We have also found that silencing of mesotrypsin expression in prostate cancer cells inhibits invasiveness in culture and metastasis in an orthotopic mouse model, while treatment of prostate cancer cells with recombinant mesotrypsin stimulates invasive behavior. Our preliminary data suggest that mesotrypsin promotes prostate cancer progression through cleavage of one or more specific substrates in the extracellular matrix (ECM), leading to upregulation of COX-2 and stimulation of invasive behavior. We hypothesize that mesotrypsin may represent both a potential therapeutic target for metastatic prostate cancer and a useful prognostic tissue biomarker of systemic progression. Here, we propose experiments (1) to further define the biological mechanisms by which mesotrypsin promotes prostate cancer progression, (2) to develop potent and selective mesotrypsin inhibitors that will facilitate mechanistic studies in culture and animal models and offer candidates for mesotrypsin-targeted therapeutics, and (3) to evaluate mesotrypsin as a prognostic tissue biomarker.
In Aim 1, we will identify proteolytic substrates of mesotrypsin in ECM using a proteomic approach, and test their impact on invasion using 3D culture models. We will also determine the mechanisms by which mesotrypsin regulates COX-2 transcription using promoter-reporter assays and RNA interference approaches.
In Aim 2, we will employ structure-guided protein engineering to optimize a polypeptide inhibitor of mesotrypsin, and evaluate the impact of this inhibitor on invasion in culture assays and on tumor growth and metastasis in an orthotopic mouse model.
In Aim 3, we will assess mesotrypsin protein staining as a potential prognostic tissue biomarker in a high-risk radical prostatectomy cohort, using a newly developed selective mesotrypsin antibody. We will also determine whether mesotrypsin expression is associated with metastasis to specific organ sites, using a diverse panel of metastatic tissues. The successful completion of these aims will critically improve our understanding of novel molecular mechanisms that underlie prostate cancer progression.

Public Health Relevance

Prostate cancer is the second leading cause of cancer death in men, and metastasis, the spread of cancer from the primary tumor to other organs, is the main cause of death. We have identified mesotrypsin as an enzyme involved in the spread of prostate cancer. By learning more about the role of mesotrypsin in prostate cancer progression, by creating drugs that target mesotrypsin function, and by developing ways to measure mesotrypsin in prostate cancer tissue, we hope to develop new therapies for treating prostate cancer and new prognostic tests to guide treatment strategies for prostate cancer survivors.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
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Basic Mechanisms of Cancer Therapeutics Study Section (BMCT)
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Snyderwine, Elizabeth G
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Mayo Clinic Jacksonville
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Cohen, Itay; Naftaly, Si; Ben-Zeev, Efrat et al. (2018) Pre-equilibrium competitive library screening for tuning inhibitor association rate and specificity toward serine proteases. Biochem J 475:1335-1352
Shirian, Jason; Arkadash, Valeria; Cohen, Itay et al. (2018) Converting a broad matrix metalloproteinase family inhibitor into a specific inhibitor of MMP-9 and MMP-14. FEBS Lett 592:1122-1134
Naftaly, Si; Cohen, Itay; Shahar, Anat et al. (2018) Mapping protein selectivity landscapes using multi-target selective screening and next-generation sequencing of combinatorial libraries. Nat Commun 9:3935
Radisky, Evette S; Raeeszadeh-Sarmazdeh, Maryam; Radisky, Derek C (2017) Therapeutic Potential of Matrix Metalloproteinase Inhibition in Breast Cancer. J Cell Biochem 118:3531-3548
Mehner, Christine; Oberg, Ann L; Goergen, Krista M et al. (2017) EGFR as a prognostic biomarker and therapeutic target in ovarian cancer: evaluation of patient cohort and literature review. Genes Cancer 8:589-599
Kayode, Olumide; Huang, Zunnan; Soares, Alexei S et al. (2017) Small molecule inhibitors of mesotrypsin from a structure-based docking screen. PLoS One 12:e0176694
Arkadash, Valeria; Yosef, Gal; Shirian, Jason et al. (2017) Development of High Affinity and High Specificity Inhibitors of Matrix Metalloproteinase 14 through Computational Design and Directed Evolution. J Biol Chem 292:3481-3495
Kayode, Olumide; Wang, Ruiying; Pendlebury, Devon F et al. (2016) An Acrobatic Substrate Metamorphosis Reveals a Requirement for Substrate Conformational Dynamics in Trypsin Proteolysis. J Biol Chem 291:26304-26319
Cohen, Itay; Kayode, Olumide; Hockla, Alexandra et al. (2016) Combinatorial protein engineering of proteolytically resistant mesotrypsin inhibitors as candidates for cancer therapy. Biochem J 473:1329-41
Mehner, Christine; Miller, Erin; Nassar, Aziza et al. (2015) Tumor cell expression of MMP3 as a prognostic factor for poor survival in pancreatic, pulmonary, and mammary carcinoma. Genes Cancer 6:480-9

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