Enzymatic stability, solution structure, and antiproliferative effect on prostate cancer cells of leuprolide and new gonadotropin-releasing hormone peptide analogs
| Autor: | Panagiotis Katsoris, Paul Cordopatis, Eleni V. Pappa, Zoi Diamantopoulou, Fotini N. Lamari, Georgios A. Spyroulias, George Pairas, Aikaterini A. Zompra, Zinovia Spyranti |
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| Rok vydání: | 2010 |
| Předmět: |
Male
endocrine system Antineoplastic Agents Hormonal Stereochemistry Biophysics Peptide Gonadotropin-releasing hormone Biochemistry Protein Structure Secondary Biomaterials Structure-Activity Relationship Protein structure Cell Line Tumor LNCaP Structure–activity relationship Humans Nuclear Magnetic Resonance Biomolecular Cell Proliferation chemistry.chemical_classification Organic Chemistry Subtilisin General Medicine Nuclear magnetic resonance spectroscopy Enzyme chemistry Leuprolide hormones hormone substitutes and hormone antagonists |
| Zdroj: | Biopolymers. 96(3) |
| ISSN: | 0006-3525 |
| Popis: | Analogs of GnRH, including [DLeu6, desGly1o]-GnRH-NHEt (leuprolide, commercial product), have been widely used in oncology to induce reversible chemical castration. Several studies have provided evidence that, besides their pituitary effects, GnRH analogs may exert direct antiproliferative effects on tumor cells. To study the effect of modifications in positions 4 and 6 of leuprolide on prostate cancer cell proliferation, we synthesized 12 new leuprolide analogs. All GnRH analogs lacked the carboxy-terminal Gly10-amide of GnRH, and an ethylamide residue was added to Pro9. Gly6 was substituted by DLys, Nepsilon-modified DLys, Glu, and DGlu. To improve the enzymatic stability, NMeSer was incorporated in position 4, and the rate of hydrolysis by alpha-chymotrypsin and subtilisin was investigated. Our results demonstrate that this incorporation increases enzymatic stability in all analogs of GnRH, whereas the antiproliferative effect on PC3 and LNCaP prostate cancer cells is similar to that of leuprolide. Conformational studies were performed to elucidate structural changes occurring on substitution of native residues and to study structure-activity relationship for these analogs. The solution models of [DLeu6, desGly10]-GnRH-NHEt (leuprolide), [NMeSer4, DGlu6, desGly10]-GnRH-NHEt, [Glu6, desGly10]-GnRH-NHEt, and [DGIu6, desGly10]-GnRH-NHEt peptides were determined through two-dimensional nuclear magnetic resonance spectroscopy in dimethylsulfoxide. Nuclear magnetic resonance data provide experimental evidence for the U-turn-like structure appeared in all four analogs, which could be characterized as beta-hairpin conformation. The most stable analog [NMeSer4, DGlu6, desGly10]-GnRH-NHEt against proteolytic cleavage forms a second extra backbone turn observed for residues 1-4. |
| Databáze: | OpenAIRE |
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