Transcript The Efficacy of Synthetic Steroids to Inhibit Hormonal

The Efficacy of Synthetic Steroids to
Inhibit Hormonal Receptors
Malik D. Lewis
Howard University
Department of Chemistry
07-26-07
Outline
 Introduction to Steroids
 Purposes of Hormonal Research
 Specific Synthetic Steroids
 Structure and Activity
 Research 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
 β- denotes the substituents above
12
18
2
3
9
4
5 6
A 10 B 87
the plane
R
17
19 11 C 13
1
20
21
D 16
R
14 15
 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 ligandregulated 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
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.
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.
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.
 Substituents
bearing:
 Sulfoxide Derivatives
 Nitrogen Derivatives
 Cyclic groups
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 19nortestosterone 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
HO
1
1. PCC, CH2Cl2
2. oxalic acid, ethanol
O
2
Research Focus
O
2
Ac2O, CH3COCl,
pyridine, reflux,
N2, 3 h
O
O
3
Research Focus
O
O
3
DMF, NBS,N2
0oC, 1 h
O
Br
O
4
Research Focus
Br
O
O
4
Li2CO3, LiBr,
N2, 95oC, 3 h
O
5
Research Focus
R MgBr
O
5
CuCl, THF
O
R
6
Research Focus
 Characterization of
compound:



FTIR
GC/MS
1H NMR
HO
1
1. PCC, CH2Cl2
2. oxalic acid, ethanol
O
2
Acknowledgements
 NIH-NCI Howard-Hopkins Partnership Grant
 AGEP Program
Special Thanks to
Dr. Oladapo Bakare, PhD
and the students of his lab