, Volume 15, Issue 2, pp 217–224 | Cite as

Comparative tissue distribution of the processing enzymes “prohormone thiol protease”, and prohormone convertases 1 and 2, in human PTHrP-producing cell lines and mammalian neuroendocine tissues

  • Leonard J. Deftos
  • Douglas Burton
  • Randolph H. Hastings
  • Robert Terkeltaub
  • Vivian Y. H. Hook


Peptide hormones are generated by proteolytic processing of their respective protein precursors by several prohormone processing proteases. The peptide hormone PTHrP is widely expressed in normal and malignant tissues, where proPTHrP undergoes proteolytic processing to generate PTHrp peptides with distinct biological actions. In this study, the tissue distribution of the prohormone processing enzymes PTP, PC1, and PC2 were compared by immunohistochemistry in human PTHrP-producing cancer cell lines, and in mammalian neuroedocrine and other tissues from rat and bovine that contain peptide hormones. PTP, PC1, and PC2 were prominently expressed in PTHrP-expressing human cancer cell lines originating from tumors of the breast, lung prostate, as well as lymphoma. These processing enzymes also showed significant expression in normal mammalian neuroendocrine tissues from bovine and rat, including pituitary, hypothalamus, adrenal medulla, pancreas, and oter tissue. Most neuroendocrine tissues contained prominent levels of at least two of the three processing enzymes examined, and all tissues contained at least one of these three enzymes. Differential expression of processing enzyme proteins was also demonstrated by Western blots. The differential expression of PTP, PC1 and PC2 observed in certain cancer and normal neuroendocrine cell types postulates selective roles for these processing enzymes in different tissues for generating biologically active peptide hormones. Theses results support the importnce of these processing enzymes in their hypothesized roles in prohormone processing.

Key Words

Proteases porthormone processing PTP PC1 PC2 PTHrP neuroendocrine 


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  1. 1.
    Hook, V. Y. H., Azaryan, A. V., Hwang, S. R., and Tezapsidis, N. (1994). Proteases and the emering role of protease inhibitors in prohormone processing. FASEB J. 8, 1269–1278.PubMedGoogle Scholar
  2. 2.
    Seidah, N. G., Mbikay, M., Marcinkiewicz, M., and Chretien, M. (1998). The mammalian precursor convertases; paralogs of the subtilisin/kexin family of calcium-dependent serine proteinases. In: Proteolytic and cellular mechanisms in prohormone and proprotein processing, Hook, V. Y. H. (ed.), R. G. Landes Company: Austin, Texas, pp. 49–69.Google Scholar
  3. 3.
    Zhou, A., Webb, G., Zhu, X., and Steiner, D. F. (1999). Proteolytic processing in the secretory pathway. J. Biol. Chem. 274, 20,745–20,748.Google Scholar
  4. 4.
    Rabbani, S. A. (2000). Molecular mechanism of action of parathyroid hormone related peptide in hypercateemica of malingnancy: therapeutic strageties. Int. J. Oncol. 16, 197–206.PubMedGoogle Scholar
  5. 5.
    Strewler, G. J. (2000). The physiology of PTHrP. N. Engl. J. Med. 342, 177–185.PubMedCrossRefGoogle Scholar
  6. 6.
    Terkeltaub, R. A., Martin, L., Johnson, K., Deng, D., Hashimoto, S., Goldring, M., Burton, D., and Deftos, L. J. (1998). Parathyroid hormone related protein (PTHrP) is abundant in osteoarthritic cartilage, and the PTHrP 1–172 isoform is selectively induced by TFGβ in articular chondrocytes and suppresses pyrophosphate elaboration. Arthritis and Rheumatism 41, 2152–2164.PubMedCrossRefGoogle Scholar
  7. 7.
    Steiner, D. F. (1998) The proprotein convertases. Curr. Opin. Chem. Biol. 2, 31–39.PubMedCrossRefGoogle Scholar
  8. 8.
    Schiller, M. R., Mende-Mueller, L., Miller, K. W., and Hook, V. Y. H. (1995). ‘Prohormone thiol protease’ (PTP) processing of recombinant proenkephalin. Biochemistry 34, 7988–7995.PubMedCrossRefGoogle Scholar
  9. 9.
    Hook, V. Y. H., Kang, Y. H., Schiller, M., Tezapsidis, N., Johnston, J. M., and Azaryan, A. (1998). ‘Prohormone thiol protease’ (PTP), a novel cysteine protease for proenkephalin and prohormone processing. In: Proteolytic and cellular mechanisms in prohormone and proprotein processing. Hook, V. Y. H. (ed.). R. G. Landes Company: Austin, Texas, pp. 89–103.Google Scholar
  10. 10.
    Yasothornsrikul, S., Aaron, W., Toneff, T., and Hook, V. Y. H., (1999). Evidence for the proenkephalin processing enzyme ‘prohormone thiol protease’ (PTP) as a multicatalytic cysteine protease complex: activation by glutathione localized to secretory vesicles. Biochemistry 38, 7421–7430.PubMedCrossRefGoogle Scholar
  11. 11.
    Loh, Y. P., Parish, D. C., and Tuteja, R. (1985). Purification and characterization of a paired basic residue-specific proopiomelanocortin converting enzyme from bovine pituitary intermediate lobe secretory vesicles. J. Biol. Chem. 260, 7194–7205.PubMedGoogle Scholar
  12. 12.
    Azaryan, A. V., Wong, M., Friedman, T. C., and Loh, Y. P., (1993). Purification and characterization of a paired basic residue specific yeast aspartic protease encoded by the YAP3 gene, similarity to the mammalian pro-opiomelnocortin-converting enzyme. J. Biol. Chem. 268, 11,968–11,975.Google Scholar
  13. 13.
    Cawley, N. X., Cool, D. R., Normant, E., Shen, F. S., Olsen, V., and Loh, Y. P. (1998). The mechanisms of sorting proopiomelanocortin to secretory granule and its processing by aspartic and PC enzymes. In: Proteolytic and cellular mechanisms in prohormone and proprotein processing. Hook, V. Y. H. (ed.). R. G. Landes Company: Austin, Texas, pp. 29–47.Google Scholar
  14. 14.
    Hook, V. Y. H., Schiller, M. R., and Azaryan, A. V. (1996). The processing proteases ‘prohormone thiol protease’ (PTP), PC1/3 and PC2, and 70 kDa aspartic proteinase show preferences among proenkephalin, pro-neuropeptide Y, and proopiomelanocortin substrates. Arch. Biochem. Biophys. 328, 107–114.PubMedCrossRefGoogle Scholar
  15. 15.
    Azaryan, A. V., and Hook, V. Y. H. (1994). Unique cleavage specificity of ‘prohormone thiol protease’ related to proenkephalin processing. FEBS Lett. 341, 197–202.PubMedCrossRefGoogle Scholar
  16. 16.
    Azaryan, A. V., and Hook, V. Y. H. (1994) Distinct properties of ‘prohormone thiol protease’ (PTP) compared to cathepsins B, L, and H: evidence for PTP as novel cysteine protease. Arch. Biochem. Biophys. 314, 171–177.PubMedCrossRefGoogle Scholar
  17. 17.
    Hook, V. Y. H., Noctor, S., Sei, C., Toneff, T., Yasothorasrikul, S., Byrne, M., Tezapsidis, N., Johnston, J., and Kang, Y. H. (1999). Localization of the proenkephalin processing enzyme “prohormone thiol protease” (PTP) to secretory vesicles of bovine chromaffin cells. Endocrinology 140, 3744–3754.PubMedCrossRefGoogle Scholar
  18. 18.
    Brandt, D. W., Burton, D. W., Gazdar, A. F., Oie, H. E., and Deftos, L. J. (1991). All major lung cancer cell types produce parathyroid hormone-like protein: heterogeneity assessed by high performance liquid chromatography. Endocrinology 129, 2455–2470.CrossRefGoogle Scholar
  19. 19.
    Deftos, L. J. (1998). Granin-A, parathyroid hormone related protein, and calcitonin gene products in neuroendocrine prostate cancer. The Prostate 8, 23–31.CrossRefGoogle Scholar
  20. 20.
    Deftos, L. J., Gazdar, A. F., Ikeda, K., and Broadus, A. E. (1989). The parathyroid hormone-related protein associated with malignancy is secreted by neuroendocrine tumors. Mol. Endocrinol. 3, 503–508.PubMedCrossRefGoogle Scholar
  21. 21.
    Burton, D. W., Brandt, D. W., and Deftos, L. J. (1994). Parathyroid hormone-related protein in the cardiovascular system. Endocrinology 135, 253–261.PubMedCrossRefGoogle Scholar
  22. 22.
    Azaryan, A. V., Krieger, T. J., and Hook, V. H. H. (1995). Characteristics of the candidate prohormone processing proteases, PC2 and PC1/3, from bovine adrenal medulla chromaffin granules. J. Biol. Chem. 270, 8201–8208.PubMedCrossRefGoogle Scholar
  23. 23.
    Sannino, P. and Shousha, S. (1994). Demonstration of oestrogen receptors in paraffin wax sections of breast carcinoma using the monoclonal antibody ID5 and microwave oven processing. J. Clin. Pathol. 47, 90–92.PubMedGoogle Scholar
  24. 24.
    Azaryan, A. V., Schiller, M. R., and Hook, V. Y. H. (1995). Chromaffin granule aspartic proteinase processes recombinant proopiomelanocortin. Biochem. Biophys. Res. Commun. 215, 937–944.PubMedCrossRefGoogle Scholar
  25. 25.
    Blalock, J. E. (1999). Proopiomelanocortin and the immune-neuroendocrine connection. Ann. NY Acad. Sci. 885, 161–172.PubMedCrossRefGoogle Scholar
  26. 26.
    Lazure, C., Authier, D., Jean, F., Boudreault A., Seidah, N. G., Bennet, H. P., and Hendy, G. N. (1998). In vitro cleavage of internally quenched fluorogenic human proparathyroid hormone and proparathyroid-related peptide substrates by furin, generation of a potent inhibitor. J. Biol. Chem. 273, 8572–9580.PubMedCrossRefGoogle Scholar
  27. 27.
    Krieger, S. R., Brownstein, M. J., and Martin, J. B. (1983). Brain Peptides, John Wiley & Sons, New York.Google Scholar
  28. 28.
    Furuta, M., Carroll, R., Martin, S., Swift, H. H., Ravazzola, M., Orci, L., and Steiner, D. F. (1998). Incomplete processing of proinsulin to insulin accompanied by elevation of Des-31,32 proinsulin intermediates in islets of mice lacking active PC2. J. Biol. Chem. 273, 3431–3437.PubMedCrossRefGoogle Scholar
  29. 29.
    Bennett, D. L., Bailyes, E. M., Nielsen, E., Guest, P. C., Rutherford, N. G., Arden, S. D., and Hutton, J. C. (1992). Identification of the type 2 proinsulin processing endopeptidase as PC2, a member of the eukaryote subtilisin family. J. Biol. Chem. 267, 15,229–15,236.Google Scholar
  30. 30.
    Bailyes, E. M., Shennan, K. I., Seal, A. J., Smeekens, S. P., Steiner, D. F., Hutton, J. C., and Docherty, K. (1992). A member of the eukaryotic subtilisin family (PC3) has the enzymic properties of the type 1 proinsulin-converting endopeptidase. Biochem. J. 285, 391–394.PubMedGoogle Scholar
  31. 31.
    Hook, V. Y. H. and Reisine, T. D. (2000). Endorphins. In: Encyclopedia of molecular medicine. Creighton, T. E. (ed.), in press.Google Scholar

Copyright information

© Human Press Inc 2001

Authors and Affiliations

  • Leonard J. Deftos
    • 1
    • 2
  • Douglas Burton
    • 1
    • 2
  • Randolph H. Hastings
    • 3
  • Robert Terkeltaub
    • 1
    • 2
  • Vivian Y. H. Hook
    • 3
    • 4
  1. 1.Dept. of MedicineUniversity of CaliforniaSan Diego, La Jolla
  2. 2.Dept. of NeurosciencesUniversity of CaliforniaSan Diego, La Jolla
  3. 3.Dept. of AnesthesiologyUniversity of CaliforniaSan Diego, La Jolla
  4. 4.Buck Institute for Age ResearchNovato

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