the efficacy of synthetic steroids to inhibit hormonal receptors

The Efficacy of Synthetic Steroids to Inhibit Hormonal

Receptors

Malik D. LewisHoward University

Department of Chemistry07-26-07

Outline

Introduction to SteroidsPurposes of Hormonal ResearchSpecific Synthetic SteroidsStructure and ActivityResearch Focus

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)

Steroids

Configuration of Steroids

A B

C D1

23

4 5 678

910

11

12

13

14 15

16

1718

19

2021

β- denotes the substituents above the plane

R

R

α- denotes the substituents below the plane

Lednicer, D. Strategies for Organic Drug Synthesis and Design. New York: John Wiley & Sons, 1998, (84-145)

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)

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.

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.

Androgenic Hormones and Receptors Main Androgens

Testosterone

5α-dihydrotestosterone

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.

Androgen Receptor Antagonists Ligand-binding domain is the site at which the

antagonist inhibits the helix 12 folding.

Flutamide and Bicalutimide Finasteride

Mifepristone

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.

Muddana, S. S.; Price, A. M.; MacBride, M. M.; Peterson, B. R.; J. Med. Chem. 2004, 47, 4985.

Synthetic Steroids

Primary Focus:

7α- methylnortestosterone substituted dihydrotestosterone

11β- methyl substituent alkyl-Δ9-19-nortestosterone

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.

Muddana, S. S.; Price, A. M.; MacBride, M. M.; Peterson, B. R.; J. Med. Chem. 2004, 47, 4985.

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.

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.

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.

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.

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.

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.

Research Focus

HO1. PCC, CH2Cl2

2. oxalic acid, ethanol

O

1

2

Research Focus

O

Ac2O, CH3COCl,pyridine, reflux,N2, 3 h

O

O

2

3

Research Focus

O

O DMF, NBS, N2

0oC, 1 h

O

O

Br

3

4

Research Focus

O

O

O

Li2CO3, LiBr,

N2, 95oC, 3 h

Br4

5

Research Focus

O R MgBr

CuCl, THF

O R

5

6

Research Focus

Characterization of compound: FTIR GC/MS 1H NMR

HO1. PCC, CH2Cl2

2. oxalic acid, ethanol

O

1

2

Acknowledgements

NIH-NCI Howard-Hopkins Partnership Grant AGEP Program

Special Thanks to

Dr. Oladapo Bakare, PhD

and the students of his lab