The Efficacy of Synthetic Steroids to Inhibit Hormonal Receptors

1. The Efficacy of Synthetic Steroids to Inhibit Hormonal Receptors Malik D. Lewis Howard University Department of Chemistry 07-26-07

2. Outline • Introduction to Steroids • Purposes of Hormonal Research • Specific Synthetic Steroids • Structure and Activity • Research Focus

3. Steroids • Steroid Nucleus- Tetracyclic structure • Four Groups of Mammalian Hormones • Estrogen • Androgen • Progestin • Corticosteroid Lednicer, D. Strategies for Organic Drug Synthesis and Design. New York: John Wiley & Sons, 1998, (84-145)

4. Steroids • Configuration of Steroids • β- denotes the substituents above the plane • α- denotes the substituents below the plane Lednicer, D. Strategies for Organic Drug Synthesis and Design. New York: John Wiley & Sons, 1998, (84-145)

5. Steroids • Cholesterol is the metabolic starting point for endogenous synthesis of all other steroids. • Stereochemical and Structural complexities prohibit total exogenous syntheses. Lednicer, D. Strategies for Organic Drug Synthesis and Design. New York: John Wiley & Sons, 1998, (84-145)

6. Estrogen and Androgen • Mutations of the DNA sites • Recruitment of components of transcriptional machinery • Activate expression in specific genes • Producing translocation of hormone receptor into nucleus Muddana, S. S.; Price, A. M.; MacBride, M. M.; Peterson, B. R.; J. Med. Chem.2004, 47, 4985.

7. Prostate Cancer • -has the greatest incidence of death among men in the United States. • - growth is incumbent on androgenic hormones which are also used in hormone replacement therapy. Tachibana, K.; Imaoka, I.; Yoshino, H.; Emura, T.; Kodama, H.; Furuta, Y.; Kato, N.; Nakamura, M.; Ohta, M.; Taniguchi, K.; Ishikura, N.; Nagamuta, M.; Onuma, E.; Sato, H.; Bioorg. Med. Chem.2007, 15, 174.

8. Androgenic Hormones and Receptors • Main Androgens • Testosterone • 5α-dihydrotestosterone

9. Cancer treatment • Antiestrogens and antiandrogens are utilized to treat breast cancer and prostate cancer, respectively. • Antagonists act by disrupting the transcription factor proteins that contribute to ligand-regulated gene expression.

10. Androgen Receptor Antagonists • Ligand-binding domain is the site at which the antagonist inhibits the helix 12 folding. • Flutamide and Bicalutimide • Finasteride • Mifepristone Muddana, S. S.; Price, A. M.; MacBride, M. M.; Peterson, B. R.; J. Med. Chem.2004, 47, 4985. Tachibana, K.; Imaoka, I.; Yoshino, H.; Emura, T.; Kodama, H.; Furuta, Y.; Kato, N.; Nakamura, M.; Ohta, M.; Taniguchi, K.; Ishikura, N.; Nagamuta, M.; Onuma, E.; Sato, H.; Bioorg. Med. Chem.2007, 15, 174.

11. Synthetic Steroids • Primary Focus: • 7α- • methylnortestosterone • substituted dihydrotestosterone • 11β- • methyl substituent • alkyl-Δ9-19-nortestosterone Muddana, S. S.; Price, A. M.; MacBride, M. M.; Peterson, B. R.; J. Med. Chem.2004, 47, 4985. Tachibana, K.; Imaoka, I.; Yoshino, H.; Emura, T.; Kodama, H.; Furuta, Y.; Kato, N.; Nakamura, M.; Ohta, M.; Taniguchi, K.; Ishikura, N.; Nagamuta, M.; Onuma, E.; Sato, H.; Bioorg. Med. Chem.2007, 15, 174.

12. Activity • Relative binding affinity with receptor. • Reporter gene assays performed with hAR-transfected HeLa cells. Tachibana, K.; Imaoka, I.; Yoshino, H.; Emura, T.; Kodama, H.; Furuta, Y.; Kato, N.; Nakamura, M.; Ohta, M.; Taniguchi, K.; Ishikura, N.; Nagamuta, M.; Onuma, E.; Sato, H.; Bioorg. Med. Chem.2007, 15, 174.

13. Activity • Agonistic Activity – • FI5 – concentration of compound-treated group in which the transcriptional activity is five times the transcriptional activity of the case without the compound. • Antagonistic Activity – • IC50 – concentration of compound to inhibit the transcriptional activity of 0.1 nM of DHT by 50% Tachibana, K.; Imaoka, I.; Yoshino, H.; Emura, T.; Kodama, H.; Furuta, Y.; Kato, N.; Nakamura, M.; Ohta, M.; Taniguchi, K.; Ishikura, N.; Nagamuta, M.; Onuma, E.; Sato, H.; Bioorg. Med. Chem.2007, 15, 174.

14. Structure and Activity • 7α- substituents hypothesized to have great Antagonistic activity based on study of ERβ LBD. • Optimal Length reported was 16-18 atoms. • Study tested 7α-dihydrotestosterones within a range of 11-19 atoms. • Sulfoxide Derivatives • Nitrogen Derivatives • Cyclic groups • Substituents bearing: Tachibana, K.; Imaoka, I.; Yoshino, H.; Emura, T.; Kodama, H.; Furuta, Y.; Kato, N.; Nakamura, M.; Ohta, M.; Taniguchi, K.; Ishikura, N.; Nagamuta, M.; Onuma, E.; Sato, H.; Bioorg. Med. Chem.2007, 15, 174.

15. Structure and Activity • 11β – utilized competition flourescence polarization assays compare affinities of 19-nortestosterone derivatives. • Greater the side chain length = greater affinity to Androgen receptor. Muddana, S. S.; Price, A. M.; MacBride, M. M.; Peterson, B. R.; J. Med. Chem.2004, 47, 4985.

16. Structure and Activity • Antiandrogens show partial agonist activity. • Receptors maintain the ability to modify their conformations in response to ligands. • Current therapeutic antiandrogens exhibit “low relative binding affinities, low selectivity across the nuclear hormone receptor superfamily, or agonist activity toward androgen receptor mutants that can emerge in advanced prostate cancer”. Cook, C. E.; Kepler, J. A.; Bioorg. Med. Chem. Lett.2005, 15, 1213.

17. Cholesterol Derivatives • Cholesterol derivatives allow for “an abundant plasma-membrane-associated steroid that controls membrane fluidity” to be “covalently bonded to proteins in cellular signaling”. Hussey,S. L.; He, E.; Peterson, B.; Org. Lett., Vol. 4, No. 3, 2002, 416.

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23. Research Focus • Characterization of compound: • FTIR • GC/MS • 1H NMR

24. Acknowledgements • NIH-NCI Howard-Hopkins Partnership Grant • AGEP Program Special Thanks to Dr. Oladapo Bakare, PhD and the students of his lab