During a biological inflammatory response, patrolling leukocytes (white blood cells) release chemokines a type of peptide cytokine - to summon other leukocytes. Inhibition of this process could provide a
mechanism for new anti-inflammatory drugs.
Chemistry Tipping the
Biological Seesaw
Sophie C. Royall & David J. Fox*
Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, U.K.
Email: s.c.royall@warwick.ac.uk, d.j.fox@warwick.ac.uk
Department of
 NR58-3.14.3 is a BSCI. It is
a
cyclic
peptide
with
the
critical motif being
WIQ.
 Sometimes
inflammation
is
inappropriate
and
can
exacerbate certain diseases for
example cancer, arthritis and
asthma.
Traditionally inhibition has been sought by blocking chemokine receptors with antagonists, but we have
found useful molecules by inhibiting functional cell migration – with great success.
 Due
to
their
role
in
initiating
inflammation
chemokines are therefore a good
target
for
anti-inflammatory
drugs – for example BSCIs.
C
S
L
C
S
 FX97L is a 40 pM BSCI.1 The
Q motif is mimicked by a
caprolactam which retains the
amide and has been found
to
be
a
successful
pharmacological component.
chemokine
inhibition
Q
 However,
it
has
been
discovered that BSCIs do not
bind to chemokine receptors but
to
the
sstr2
receptor
for
somatostatin.
F N
A
HH O
N
D
F
C
S
WSomatostatin
S C
14
K
S
T
T
F
Q
K
NH
O
K
 Somatostatin
is
a
peptide
involved in growth hormone (GH)
regulation.2
FX97L 40 pM BSCI
G
 An example
ligand based
motif.
of
on
O O
S
N
H
N
H HN
 It is a cyclic peptide with
the critical motif being KWF.3
K
I
NR58-3.14.3 W
P
We would not have discovered Broad-Spectrum Chemokine Inhibitors (BSCIs) using a receptor antagonist
approach as our functional screening approach has discovered a new biological target for anti-inflammatory
drug design – the sstr2 receptor.
O
O
an sstr2
the KWF.
O
NH
H
O
H2N
sstr2 ligand based on WKF critical motif
GH regulation
 The sstr2 receptor therefore displays functional selectivity – when somatostatin is bound GH
is affected but when BSCIs are bound chemokines are affected.4
 Functional selectivity is the ability for a receptor to have different functions depending
on the molecule to which it is bound.
somatostatin
BSCIs
sstr2 receptor
sstr2 receptor
sstr2 receptor
sstr2 receptor
sstr2 receptor
GH regulated?
GH regulated
O
H
N
O
O
O
S
O O
'anti-inflammatory'
binding site
Growth Hormone regulation binding site
N
S
O O
NH2
HN
Growth Hormone regulation binding site
'anti-inflammatory'
binding site
O
O
N
H
N
OO
S
O O
HN
N
H
'anti-inflammatory'
binding site
BSCIs to investigate the important part of the molecules for tipping sstr2 from GH to BSCI function.
O
1
HN
2
HN
3
HN
O
NH
O
NH
5
O
NH
6
HN
NH
7
HN
8
HN
O
O
O
NH
F
Somatostatin
14
F
O
S
O
N
O
S
O
O
S
O
N
O
S
O
N
O
S
O
N
OO
O
S
O
H
N
N
O O
OH
+
O O
S
Cl
H
N
O
O O
S
N
1) Et3N
OH
W
N
O
S
O
3) HCl/dioxane
+
ClH3N
H
O
O O
H
N
HN
OH
N
O
S
O
1) HATU, Et3N
NH
2) H2/Pd/C
4) 4-ClSO2C6H4COOH, Et3N
F analogue, 9
HO
HN
O
O
O
NH
H
N
H
N
NHBoc
O
OH
H
N
1) HATU, Et3N, R-NH2
2) MeSO2OH
H
N
NH2
O
O
NHH
NH2
O
NH
FQ analogue, 10
H
N
NH2
O
NH
NH2
9 or 10
O
CbzHN
KW analogue, 11
CbzHN
KW analogue, 12
W analogue, 13
1) HATU, Et3N, amines 11,
12, 13 or 14
(commerically available)
W analogue, 14
2) Pd,C, H2
OO
OO
HN
NH
NH
HN
K
'anti-inflammatory'
binding site
Growth Hormone regulation binding site
 The smaller BSCIs such as FX97L or a
benzoyl analogue are non-competitive in
their
binding
with
regards
to
somatostatin.
 A series of
benzoyl amino lactams were
synthesised
with
different
length
alkyl
chains to determine the point at which they
start becoming competitive with somatostatin.
'anti-inflammatory'
binding site
sstr2
sstr2
N
O
1) Boc2O, Na2CO3
N
H
H
N
OBn
2) BnBr, KOH
OH
O O
O
S
O
BSCI analogue (WFQ)
O
N
H
N
HN
Hybrid? (KWFQ)
O
O
O
S
O
HN
HN
Somatostatin analogue (KWF)
sstr2
T
Growth Hormone regulation binding site
N
Growth Hormone regulation binding site
S
S S
F
O
NH
'anti-inflammatory'
binding site
T
NH
HN
'anti-inflammatory'
binding site
C
N
O
4
HN
O
O
O
NH
NH
O
NH
O
NH
O
K
NH
NH
NH
NH
HN
A G
O
O
NH
Binding: Competitive or non-competitive
H2N
O
H2N
H2N
HN
OO
sstr2
C
H2N
S
O O
Growth Hormone regulation binding site
sstr2
The aim of my project is to synthesise a catalogue of molecules analogous to both somatostatin and
OO
N
H
Growth Hormone regulation binding site
sstr2
N
NH
N
H
NH3
sstr2
O
OO
N
H
NH3
H
N
R
N
H
N
H
NH3
O
H
N
R
N
chemokines regulated?
chemokines regulated
O
N
H
GH and chemokines regulated?
 The larger BSCIs such as BN83250 are
competitive in their binding with regards
to somatostatin however.
n
n
H
N
O
H
N
O
NH
O
NH
O
 To determine the competitive nature of the ligands they will be subjected to an sstr2 binding assay
measuring the percentage displacement of somatostatin and a GH regulation assay.
 To determine their abilities as BSCIs they will be subjected to an in vitro leukocyte migration
assay and an in vivo anti-inflammatory activity assay.
compounds 1 - 8
1. D. J. Fox, J. Reckless, H. Lingard, S. Warren and D. J. Grainger, J. Med. Chem., 2009, 52, 3591-35
2. B. A. Hay, B. M. Cole, F. DiCapua, G. W. Kirk, M. C. Murray, R. A. Nardone, D. J. Pelletier, A. P. Ricketts,
A. S. Robertson and T. W. Siegel, Bioorg. Med. Chem. Lett., 2001, 11, 2731-2734.
3. D. J. Fox, J. Reckless, S. M. Wilbert, I. Greig, S. Warren and D. J. Grainger, J. Med. Chem., 2005, 48, 867874.
4. A. Schonbrunn, Mol. Cell. Endocrinol., 2008, 286, 35-39.