Optimization of the first selective steroid-11β-hydroxylase (CYP11B1) inhibitors for the treatment of cortisol dependent diseases

Article abstract of DOI:10.1021/ml100283h

CYP11B1 is the key enzyme in cortisol biosynthesis, and its inhibition with selective compounds is a promising strategy for the treatment of diseases associated with elevated cortisol levels, such as Cushing's syndrome or metabolic disease. Expanding on a

Full text of DOI:10.1021/ml100283h

LETTER
pubs.acs.org/acsmedchemlett
Optimization of the First Selective Steroid-11β-hydroxylase (CYP11B1)
Inhibitors for the Treatment of Cortisol Dependent Diseases
Ulrike E. Hille, Christina Zimmer, J€org Haupenthal, and Rolf W. Hartmann*
Pharmaceutical and Medicinal Chemistry, Saarland University & Helmholtz Institute for Pharmaceutical Research Saarland (HIPS),
Campus C2 3, D-66123 Saarbr€ucken, Germany
S Supporting Information
b
ABSTRACT:
CYP11B1 is the key enzyme in cortisol biosynthesis, and its inhibition with selective compounds is a promising strategy for the
treatment of diseases associated with elevated cortisol levels, such as Cushing’s syndrome or metabolic disease. Expanding on a
previous study from our group resulting in the first potent and rather selective inhibitor described so far (1, IC50 = 152 nM), we
herein describe further optimizations of the imidazolylmethyl pyridine core. Five compounds among the 42 substances synthesized
showed IC50 values below 50 nM. Most interesting was the naphth-1-yl compound 23 (IC50 = 42 nM), showing a 49-fold selectivity
toward the highly homologous CYP11B2 (1: 18-fold) as well as selectivity toward the androgen and estrogen forming enzymes
CYP17 and CYP19, respectively.
KEYWORDS: Cushing’s syndrome, metabolic syndrome, steroid hormone biosynthesis, steroid-11β-hydroxylase (CYP11B1),
CYP11B2, selective inhibitors
ndogenous Cushing’s syndrome is a hormonal disorder
therapeutics for castration refractory prostate cancer, respec-
tively. In the case of adrenal CYP11B enzymes, selectivity is very
difficult to achieve, as the homology between CYP11B1 and
CYP11B2 (aldosterone synthase, Scheme 1) is very high
(93%),13 and for a long time it was considered impossible to
obtain selective inhibitors. Recently, however, we succeeded in
the development of highly active and selective CYP11B2
inhibitors14ꢀ18 with in vivo activity.19,20 Regarding CYP11B1
inhibition, the hypnotic and unselective CYP inhibitor etomidate
was used as starting point for three investigations: Roumen et al.
discovered selective CYP11B2 inhibitors,21 Zolle et al. described
CYP11B1 inhibitors without investigating selectivity,22 and we
discovered the first rather selective CYP11B1 inhibitors.23 The
best compound identified (1, Scheme 2) shows an activity com-
parable to the clinically administered ketoconazole but strongly
exceeds its selectivity (IC50 = 152 nM, a fairly good selectivity
toward CYP11B2 (selectivity factor, sf =18) and no inhibition of
CYP17 and CYP19). For improving activity and selectivity, we
describe here structural modifications of 1 leading to 42 novel
compounds (Scheme 2). Either the phenyl ring was replaced by
small substituents (1a, 3ꢀ6), or substituents were introduced
into the phenyl ring (7ꢀ 22), and a benzene was annulated to
the phenyl moiety (23 and 24). Finally, the phenyl ring was
E
caused by prolonged exposure to excessive levels of circulat-
ing glucocorticoids; therefore, it is also called hypercortisolism.
Most people develop central obesity and often diabetes and
hypertension. In many cases, hypersecretion of ACTH is ob-
served, which is caused by a pituitary adenoma (Cushing’s
disease).1 Adrenocortical tumors are common reasons for ACTH-
independent hypercortisolism. In many cases, surgical removal of
the tumor or radiation therapy cannot be applied and patients
require temporary or permanent medication.2 However, applica-
tion of the glucocorticoid receptor antagonist mifepristone
triggers a massive secretion of cortisol which is probably caused
by the hypothalamic pituitary feedback mechanism.3 A decrease
of glucocorticoid formation should be a better therapeutic
option. The best target for such an approach is steroid-11β-
hydroxylase (CYP11B1), an adrenal CYP enzyme catalyzing the
last step in cortisol production, the hydroxylation of deoxycorti-
sol in the 11β-position (Scheme 1). There are inhibitors of
cortisol biosynthesis such as ketoconazole, etomidate, and me-
tyrapone in clinical use.4 However, all of them show severe side
effects due to the fact that they are unselective.
A challenge in the development of CYP enzyme inhibitors is
the selectivity versus other CYP enzymes. In the past, we and
others have developed selective inhibitors of steroidogenic
CYP enzymes. Aromatase (estrogen synthase, CYP19)5ꢀ8
and 17R-hydroxylase-C17,20-lyase (CYP17) inhibitors9ꢀ12 are
first line drugs for the treatment of breast cancer and upcoming
Received: December 7, 2010
Accepted: May 19, 2011
Published: June 03, 2011
r
2011 American Chemical Society
559
dx.doi.org/10.1021/ml100283h ACS Med. Chem. Lett. 2011, 2, 559–564
|

ACS Medicinal Chemistry Letters
LETTER
Scheme 1. Role of CYP11B1 and CYP11B2 in Cortisol and Aldosterone Biosynthesis
Scheme 2. Synthesized Inhibitors
Scheme 3. Synthesis of Compounds 1, 1a, and 3ꢀ42a
a Conditions: (a) Method A: NBS, DBPO, CCl4, 90 °C, 12 h. (b) Method B: imidazole, K2CO3, acetonitrile, 90 °C, 2 h. (c) Method C: boronic acid,
Pd(PPh3)4, Na2CO3, toluene/MeOH/H2O, reflux, 5 h.
exchanged by several heterocycles (25ꢀ42). All compounds
were tested for inhibition of human CYP11B1 and CYP11B2 and
selected compounds for CYP19 and CYP17 inhibition.
coupling of 6 with phenylboronic acid and furan-2-ylboronic acid
led to bis-substituted compounds 25 and 42, while reaction with
thiophen-2-ylboronic acid only replaced the bromine, not the
chlorine in 6 leading to 35. The unsubstituted pyridines 2 and 3
were obtained via SN reaction from the commercially available
bromomethylpyridines. Compound 4 was obtained from
3-methylpicolinonitrile via WohlꢀZiegler bromination and sub-
sequent SN reaction with imidazole.
The synthesis of compounds 1a and 3ꢀ42 is shown in
Scheme 3. The reaction sequence was basically as already
described.23 The key reaction leading to the final compounds
7ꢀ42 was a Suzuki coupling with the corresponding boronic
acids and compounds 5 (for the synthesis of 36), 6 (for 25, 35,
and 42) and 1a (for all other compounds). Compounds 5 and 6
were obtained from 2-bromo-3-methylpyridine or 3-bromo-2-
chloro-5-methylpyridine as starting materials. Interestingly, Suzuki
For the determination of CYP11B1 and CYP11B2 inhibition,
V79 MZ cells expressing either human CYP11B1 or CYP11B2
were used and [3H]-labeled 11-deoxycorticosterone was used as
560
dx.doi.org/10.1021/ml100283h |ACS Med. Chem. Lett. 2011, 2, 559–564

ACS Medicinal Chemistry Letters
LETTER
Table 1. Inhibition of CYP11B2 and CYP11B1 by Com-
pounds 2ꢀ22
to 1. Introduction of p-OH into 8 increased activity strongly
(11, IC50 = 17 nM). Regarding MeO substitution, only the o-MeO
compound 12 showed good CYP11B1 inhibition (IC50 = 167
nM) and a high selectivity (sf = 26). NH2 substitution resulted in
highly active compounds, no matter in which position the group
is located (15ꢀ17, IC50 = 101ꢀ110 nM). Regarding selectivity,
however, differences could be observed. Compound 16 turned
out to be the most selective compound of this series (sf = 31).
Introduction of a Me group into 16 strongly decreased inhibition
(18, IC50 = 542 nM). Further substituents, such as CN (19, 20),
formyl (21), and diphenylamino (22), did not enhance the
potency of 1.
Annulation of an additional benzene ring yielding the naph-
thalenes 23 and 24 (Table 2) resulted in a remarkable finding. In
the case of the 1-naphthyl compound 23, a strong enhancement
of activity and selectivity was observed (IC50 = 42 nM, sf = 49). In
contrast, the 2-naphthyl compound 24 showed only moderate
activity and low selectivity (IC50 = 246 nM, sf = 3).
Exchange of the phenyl moiety of 1 by nitrogen containing
heterocycles (26ꢀ30) led only in the case of 4-pyridine (27, IC50 =
139 nM) and 4-isoquinoline (30, IC50 = 95 nM) to fairly active
compounds. Contrarily, thiophene containing compounds were
in most cases highly active, like the 2-thiophene 31 and the
3-thiophene 32 (IC50 = 75 and 126 nM). Introduction of 5-Cl or
5-formyl into the thiophene ring of 31 reduced activity or did not
change it (33, 34). Interestingly, annulation of a benzene ring
onto the thiophene moiety reduced the activity of 31, whereas for
structure
R2
IC50 value (nM)a,b
no.
R1
Br
R3
CYP11B1
CYP11B2
sf c
2
3d
663
816
971
500
61
>1000
>1000
>1000
>1000
911
4
CN
Br
1a
5
15
6
Cl
R4
F
Br
R5
168
576
3.4
R6
7
72
320
213
329
17
1736
>1000
2153
1665
237
24
8
9h
10h
F
F
F
10
5
F
F
11
OH
14
26
12h
13h
14h
15
MeO
NH2
167
782
>1000
101
110
106
542
409
782
246
611
152
15
4391
>1000
>1000
2114
3407
528
compound 32 it was increased (37, IC50 = 269 nM; 38, IC50
=
MeO
MeO
40 nM). Shifting of the 2-thiophene group of 31 into other
positions did not change the activity in the case of 35 (bearing an
additional Cl-substituent) while in 36 the potency was strongly
increased (IC50 = 16 nM). The furans 39 and 40 exhibited similar
potencies to those of the thiophenes. As seen with the 2-thio-
phene 31, annulation of a benzene ring onto the 2-furan ring of
39 decreased activity (41, IC50 = 500 nM).
The introduction of an additional ring, phenyl into compound
1 and 2-furanyl into compound 39, again led to opposed results:
Compound 25 (IC50 = 362 nM) showed a somewhat reduced
activity compared to 1 whereas 42 (IC50 = 29 nM) turned out to
be more potent than 39.
The most interesting 24 compounds were tested for inhibition
of CYP17 and CYP19 (see Supporting Information). Inhibition
of CYP17 was investigated using recombinantly expressed hu-
man CYP17 and progesterone as substrate.11,26 All substances
showed no effect (inhibition values <10% at 2.0 μM). Inhibition
of CYP19 was determined with human placental microsomes
and [1β-3H]androstenedione as substrate.27 Only 33 and 34
exhibited little inhibition (30 and 19% at 0.5 μM, respectively),
while all other substances showed no effect (values <10%).
Summarizing, we succeeded in the optimization of lead com-
pound 1. The activity was enhanced for a number of inhibitors
showing IC50 values below 50 nM, and the selectivity toward the
highly homologous CYP11B2 was increased. Most of the com-
pounds exhibited no inhibition of CYP17 and CYP19. Interest-
ingly, already small compounds such as the bromo substituted 5
exhibited high inhibitory activity, while being highly selective
toward the other CYPs.
MeO
NH2
21
31
5
16h
17
NH2
Me
18
NH2
CN
>1000
>1000
>1000
>1000
n.i.e
19
20
CN
21
CHO
22
di-Ph-N
1f,h
MTPg
ETOg
KTZg
2768
72
18
4.8
0.2
0.5
0.5
0.1
127
67
a Mean value of at least three experiments. The deviations were within
< (25%. b Hamster fibroblasts expressing human CYP11B1 or
CYP11B2; substrate 11-deoxycorticosterone, 100 nM. c sf: selectivity
factor: IC50 (CYP11B2)/IC50 (CYP11B1). d Compound described in
ref 22. e n.i.: no inhibition at an inhibitor concentration of 500 nM.
f Compound described in ref 23. g MTP, metyrapone; ETO, etomidate;
KTZ, ketoconazole. h Compound described in ref 31.
substrate.24,25 Metyrapone, etomidate, ketoconazole, and 1
served as references. Compounds 2 and 3, bearing the unsubsti-
tuted pyridine ring, showed moderate inhibitory activity (Table 1).
Introduction of different substituents into 3 led to the highly active
o-Br compound 5 (IC50 = 61 nM) with a good selectivity toward
CYP11B2 (sf = 15). While introduction of o-CN and p-Br did
not change activity strongly, the p-Cl,m-Br compound 6 (IC50
=
168 nM) showed good activity but poor selectivity.
In the class of the aryl-substituted imidazolylmethyl pyridines,
important SARs have been obtained that permit the differentia-
tion between CYP11B1 and CY11B2 inhibitors. It is striking that
the o-substituted phenyl compounds 7, 12, and 15 show a higher
activity and/or selectivity than the parent compound 1. This can
Introduction of F into the phenyl moiety of 1 led to interesting
results. Compound 7 with o-F substitution showed an increase in
potency and selectivity while the m-F, p-F, and m,p-di-F com-
pounds 8ꢀ10 exhibited reduced inhibition and selectivity compared
561
dx.doi.org/10.1021/ml100283h |ACS Med. Chem. Lett. 2011, 2, 559–564

ACS Medicinal Chemistry Letters
LETTER
Table 2. Inhibition of CYP11B2 and CYP11B1 by Compounds 23ꢀ42
structure
IC50 value (nM)a,b
no.
23
R7
R8
R9
CYP11B1
CYP11B2
sf c
1-naphthalene
2-naphthalene
Ph
42
246
362
502
139
971
>1000
95
2075
782
49
3.2
2.4
8
24
25
Ph
851
26
3-pyridine
3955
487
27
4-pyridine
3.5
28
5-pyrimidine
3-(6-methoxypyridine)
4-isoquinoline
2-thiophene
n.i.d
29
>1000
914
30
10
17
26
2.6
16
6
31
75
1243
3265
929
32
3-thiophene
126
362
62
33
2-(5-chlorothiophene)
2-(5-formylthiophene)
Cl
34
968
35
2-thiophene
73
416
36
2-thiophene
16
251
16
1.0
29
31
37
37
2-benzo[b]thiophene
3-benzo[b]thiophene
2-furan
269
40
281
38
1157
5159
2832
>1000
830
39
167
76
40
3-furan
41
2-benzo[b]furan
2-furan
500
29
42
2-furan
29
1e
Ph
152
15
2768
72
18
MTPf
ETOf
KTZf
4.8
0.2
0.5
0.5
127
0.1
67
a Mean value of at least three experiments. The deviations were within < (25%. b Hamster fibroblasts expressing human CYP11B1 or CYP11B2;
substrate 11-deoxycorticosterone, 100 nM. c sf: selectivity factor: IC50 (CYP11B2)/IC50 (CYP11B1). d n.i.: no inhibition at an inhibitor concentration of
500 nM. e compound described in refs 23 and 31. f MTP, metyrapone; ETO, etomidate; KTZ, ketoconazole
also be observed with compounds 23 and 38, with an ortho-
position involved in benzene annulation, resulting in higher
activity and/or selectivity compared to 1 and 32. As o-substitu-
tion hinders rotation around the arylꢀaryl bond, leading to
nonplanarity and to an increase of “bulkiness” of the compound,
it can be concluded that the active site of CYP11B1 favors a bulky
structure whereas a flat compound geometry is preferred by the
CYP11B2 binding site. Besides these important steric impacts,
the paper shows that substituents at the phenyl group in the
meta- or para-position or exchange of the phenyl by thiophenyl
or furanyl are appropriate to modulate inhibition.
One of the most potent compounds of this series, 23, is
similarly active as the clinically used metyrapone. However, in
contrast to metyrapone, 23 is much more selective: it is the most
selective compound described so far and should be a promising
candidate for further development. Such a potent and selective
CYP11B1 inhibitor as 23 might not only be a good therapeutic
for the treatment of Cushing’s syndrome, it might also be
beneficial for treating metabolic syndrome, as elevated cortisol
levels play a central role in this disease.28 A phase IIa study using
the 2S,4R enantiomer of ketoconazole (DIO-902) with patients
suffering from type 2 diabetes and other evidence of metabolic
syndrome showed encouraging results. The levels of HbA1c and
cholesterol were reduced, as well as weight loss and decreased
blood pressure being observed.29,30
’ ASSOCIATED CONTENT
S
Supporting Information. Synthetic experimental details,
b
analytical and further biological data of compounds, and biolo-
gical assay protocols. This material is available free of charge via
the Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Author
*Phone: þ(49) 681 302 70300. E-mail: rwh@mx.uni-saarland.de.
http://www.PharmMedChem.de.
Funding Sources
U.E.H. is grateful to the European Postgraduate School 532 (DFG)
for a scholarship.
562
dx.doi.org/10.1021/ml100283h |ACS Med. Chem. Lett. 2011, 2, 559–564

ACS Medicinal Chemistry Letters
LETTER
’ ACKNOWLEDGMENT
(14) Lucas, S.; Heim, R.; Negri, M.; Antes, I.; Ries, C.; Schewe, K. E.;
Bisi, A.; Gobbi, S.; Hartmann, R. W. Novel aldosterone synthase
inhibitors with extended carbocyclic skeleton by a combined ligand-
based and structure-based drug design approach. J. Med. Chem. 2008,
51, 6138–6149.
(15) Heim, R.; Lucas, S.; Grombein, C. M.; Ries, C.; Schewe, K. E.;
Negri, M.; M€uller-Vieira, U.; Birk, B.; Hartmann, R. W. Overcoming
undesirable CYP1A2 potency of pyridylnaphthalene type aldosterone
synthase inhibitors: Influence of heteroaryl substitution on potency and
selectivity. J. Med. Chem. 2008, 51, 5064–5074.
(16) Voets, M.; Antes, I.; Scherer, C.; M€uller-Vieira, U.; Biemel, K.;
Barassin, C.; Marchais-Oberwinkler, S.; Hartmann, R. W. Heteroaryl
substituted naphthalenes and structurally modified derivatives: selective
inhibitors of CYP11B2 for the treatment of congestive heart failure and
myocardial fibrosis. J. Med. Chem. 2005, 48, 6632–6642.
(17) Ulmschneider, S.; M€uller-Vieira, U.; Mitrenga, M.; Hartmann,
R. W.; Marchais-Oberwinkler, S.; Klein, C. D. P.; Bureik, M.; Bernhardt,
R.; Antes, I.; Lengauer, T. Synthesis and evaluation of imidazolyl-
methylenetetrahydronaphthalenes and imidazolylmethyleneindanes:
potent inhibitors of aldosterone synthase. J. Med. Chem. 2005, 48,
1796–1805.
The assistance of Jeannine Jung and Jannine Ludwig in
performing the biological tests is appreciated. We thank Profes-
sors Hermans (Maastricht University) and Bernhardt (Saarland
University) for providing V79MZh11B1 and V79MZh11B2 cells.
’ ABBREVIATIONS
CYP, cytochrome P450; CYP11B1, steroid-11β-hydroxylase;
CYP11B2, aldosterone synthase; CYP17, 17R-hydroxylase-17,
20-lyase; CYP19, aromatase; HbA1c, glycosylated hemoglobin;
HSD, hydroxysteroid dehydrogenase; IC50, concentration re-
quired for 50% inhibition; SAR, structure activity relationship; sf,
selectivity factor; SN, nucleophilic substitution
’ REFERENCES
(1) Diez, J. J.; Iglesias, P. Pharmacological therapy of Cushing’s
syndrome: Drugs and indications. Mini-Rev. Med. Chem. 2007, 7,
467–480.
(18) Ulmschneider, S.; M€uller-Vieira, U.; Klein, C. D. P.; Antes, I.;
Lengauer, T.; Hartmann, R. W. Synthesis and evaluation of (pyridyl-
methylene)tetrahydronaphthalenes/-indanes and structurally modified
derivatives: potent and selective inhibitors of aldosterone synthase.
J. Med. Chem. 2005, 48, 1563–1575.
(2) Engelhardt, D.; Weber, M. M. Therapy of Cushing’s syndrome
with steroid biosynthesis inhibitors. J. Steroid Biochem. Mol. Biol. 1994,
49, 261–267.
(3) Chu, J. W.; Matthias, D. F.; Joseph Belanoff, J.; Schatzberg, A.;
Hoffman, A. R.; Feldman, D. Successful long-term treatment of refrac-
tory Cushing’s disease with high-dose mifepristone (RU 486). J. Clin.
Endocrinol. Metab. 2001, 86, 3568–3573.
(19) Ries, C.; Lucas, S.; Heim, R.; Birk, B.; Hartmann, R. W.
Selective aldosterone synthase inhibitors reduce aldosterone formation
in vitro and in vivo. J. Steroid Biochem. Mol. Biol. 2009, 116, 121–126.
(20) Lucas, S.; Heim, R.; Ries, C.; Schewe, K. E.; Birk, B.; Hartmann,
R. W. In vivo active aldosterone synthase inhibitors with improved selec-
tivity: Lead optimization providing a series of pyridine substituted 3,4-
dihydro-1H-quinolin-2-one derivates. J. Med. Chem. 2008, 51, 8077–8087.
(21) Roumen, L.; Peeters, J. W.; Emmen, J. M. A.; Beugels, I. P. E.;
Custers, E. M. G.; de Gooyer, M.; Plate, R.; Pieterse, K.; Hilbers, P. A. J.;
Smits, J. F. M.; Vekemans, J. A. J.; Leysen, D.; Ottenheijm, H. C. J.;
Janssen, H. M.; Hermans, J. J. R. Synthesis, biological evaluation, and
molecular modeling of 1-benzyl-1H-imidazoles as selective inhibitors of
aldosterone synthase (CYP11B2). J. Med. Chem. 2010, 53, 1712–1725.
(22) Zolle, I. M.; Berger, M. L.; Hammerschmidt, F.; Hahner, S.;
Schirbel, A.; Peric-Simov, B. New selective inhibitors of steroid
11β-hydroxylation in the adrenal cortex. Synthesis and structure-
activity relationship of potent etomidate analogues. J. Med. Chem.
2008, 51, 2244–2253.
(4) Nieman, K. L. Medical therapy of Cushing’s disease. Pituitary
2002, 5, 77–82.
(5) Le Borgne, M.; Marchand, P.; Duflos, M.; Delevoye-Seiller, B.;
Piessard-Robert, S.; Le Baut, G.; Hartmann, R. W.; Palzer, M. Synthesis
and in vitro evaluation of 3-(1-azolylmethyl)-1H-indoles and 3-(1-
azoly1-1-phenylmethyl)-1H-indoles as inhibitors of P450 arom. Arch.
Pharm. 1997, 330, 141–145.
(6) Leonetti, F.; Favia, A.; Rao, A.; Aliano, R.; Paluszcak, A.;
Hartmann, R. W.; Carotti, A. Design, synthesis and 3D QSAR of novel
potent and selective aromatase inhibitors. J. Med. Chem. 2004,
47, 6792–6803.
(7) Gobbi, S.; Cavalli, A.; Rampa, A.; Belluti, F.; Piazzi, L.; Paluszcak,
A.; Hartmann, R. W.; Recanatini, M.; Bisi, A. Lead optimization
providing a series of flavone derivatives as potent nonsteroidal inhibitors
of the cytochrome P450 aromatase enzyme. J. Med. Chem. 2006,
49, 4777–4780.
(23) Hille, U. E.; Zimmer, C.; Vock, C. A.; Hartmann, R. W. First
selective CYP11B1 inhibitors for the treatment of cortisol dependent
diseases. Med. Chem. Lett. 2011, 2, 2–6.
(8) Dutta, U.; Pant, K. Aromatase inhibitors: past, present and future
in breast cancer therapy. Med. Oncol. 2008, 25, 113–124.
(9) Zhuang, Y.; Wachall, B. G.; Hartmann, R. W. Novel imidazolyl
and triazolyl substituted biphenyl compounds: Synthesis and evaluation
as nonsteroidal inhibitors of human 17R-hydroxylase-C17,20-lyase-
(P450 17). Bioorg. Med. Chem. 2000, 8, 1245–1252.
(10) Leroux, F.; Hutschenreuter, T.; Charriꢀere, C.; Scopelliti, R.;
Hartmann, R. W. N-(4-Biphenylmethyl)imidazoles as potential ther-
apeutics for the treatment of prostate cancer: metabolic robustness due
to fluorine substitution?. Helv. Chim. Act. 2003, 86, 2671–2686.
(11) Hutschenreuter, T. U.; Ehmer, P. B.; Hartmann, R. W. Synth-
esis of hydroxy derivatives of highly potent non-steroidal CYP 17
inhibitors as potential metabolites and evaluation of their activity by a
non cellular assay using recombinant human enzyme. J. Enzyme Inhib.
Med. Chem. 2004, 19, 17–32.
(12) Attard, G.; Reid, A. H.; A’Hern, R.; Parker, C.; Oommen, N. B.;
Folkerd, E.; Messiou, C.; Molife, L. R.; Maier, G.; Thompson, E.; Olmos,
D.; Sinha, R.; Lee, G.; Dowsett, M.; Kaye, S. B.; Dearnaley, D.; Kheoh,
T.; Molina, A.; de Bono, J. S. Selective inhibition of CYP17 with
abiraterone acetate is highly active in the treatment of castration-
resistant prostate cancer. J. Clin. Oncol. 2009, 27, 3742–3748.
(13) Mornet, E.; Dupont, J.; Vitek, A.; White, P. C. Characterization
of two genes encoding human steroid 11β-hydroxylase [P-450(11)β].
J. Biol. Chem. 1989, 264, 20961–20967.
(24) Ehmer, P. B.; Bureik, M.; Bernhardt, R.; M€uller, U.; Hartmann,
R. W. Development of a test system for inhibitors of human aldosterone
synthase (CYP11B2): Screening in fission yeast and evaluation of
selectivity in V79 cells. J. Steroid Biochem. Mol. Biol. 2002, 81, 173–179.
(25) Denner, K.; Doehmer, J.; Bernhardt, R. Cloning of CYP11B1
and CYP11B2 from normal human adrenal and their functional expres-
sion in COS-7 and V79 chinese hamster cells. Endocrine Res. 1995,
21, 443–448.
(26) Ehmer, P. B.; Jose, J.; Hartmann, R. W. Development of a
simple and rapid assay for the evaluation of inhibitors of human 17R-
hydroxylase-C(17,20)-lyase (P450c17) by coexpression of P450c17
with NADPH-cytochrome-P450-reductase in Escherichia coli. J. Steroid
Biochem. Mol. Biol. 2000, 75, 57–63.
(27) Hartmann, R. W.; Batzl, C. Aromatase inhibitors. Synthesis and
evaluation of mammary tumor inhibiting activity of 3-alkylated 3-(4-
aminophenyl)piperidine-2,6-diones. J. Med. Chem. 1986, 29, 1362–1369.
(28) Welles, B. Glucocorticoids in type 2 diabetes mellitus and the
metabolic syndrome. Drug Dev. Res. 2006, 67, 570–573.
(29) Schwartz, S. L.; Rendell, M.; Ahmann, A. J.; Thomas, A.;
Arauz-Pachecho, C. J.; Welles, B. R. Safety profile and metabolic effects
of 14 days of treatment with DIO-902: results of a phase IIa multicenter,
563
dx.doi.org/10.1021/ml100283h |ACS Med. Chem. Lett. 2011, 2, 559–564

ACS Medicinal Chemistry Letters
LETTER
randomized, double-blind, placebo-controlled, parallel-group trial in
patients with type 2 diabetes mellitus. Clin. Ther. 2008, 6, 1081–1088.
(30) Arakaki, R.; Welles, B. Ketoconazole enantiomer for the treatment
of diabetes mellitus. Expert Opin. Investig. Drugs 2010, 19, 185–194.
(31) Jagusch, C.; Negri, M.; Hille, U. E.; Hu, Q.; Bartels, M.;
Jahn-Hoffmann, K.; Pinto-Bazurco Mendieta, M. A.; Rodenwaldt, B.;
M€uller-Vieira, U.; Schmidt, D.; Lauterbach, T.; Recanatini, M.; Cavalli,
A.; Hartmann, R. W. Synthesis, biological evaluation and molecular
modelling studies of methyleneimidazole substituted biaryls as inhibi-
tors of human 17alpha-hydroxylase-17,20-lyase (CYP17). Part I: Het-
erocyclic modifications of the core structure. Bioorg. Med. Chem. 2008,
16, 1992–2010.
564
dx.doi.org/10.1021/ml100283h |ACS Med. Chem. Lett. 2011, 2, 559–564