Bioorganic & Medicinal Chemistry Letters
A novel lead of P-selectin inhibitor: Discovery, synthesis, bioassays
and action mechanism
a
a
a
a
a,
Jianhui Wu a, Ming Zhao a,b, , Yuji Wang , Yaonan Wang , Haimei Zhu , Shurui Zhao , Shiqi Peng
⇑
⇑
a Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory
of Biomedical Materials, College of Pharmaceutical Sciences, Capital Medical University, Beijing 100069, PR China
b Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
a r t i c l e i n f o
a b s t r a c t
Article history:
By docking 126 derivatives of b-carboline-3-carboxylic acid, tetrahydro-b-carboline-3-carboxylic acid
and indoloquinolizine into the active pocket of P-selectin (2-(3-(hydroxymethyl)-9H-pyrido[3,4-b]in-
dol-1-yl)ethyl)-L-phenylalanine (HMCEF) was assigned a novel inhibitor. ELISA and flow cytometry
experiments showed that HMCEF effectively down-regulated P-selectin expression and supported the
rationality of the computer assistant screening, while UV spectrum experiments demonstrated that
HMCEF directly bound to P-selectin. In vivo HMCEF dose dependently inhibited the rats and mice to form
thrombus and had a minimal effective dose of 20 nmol/kg, dose dependently inhibited inflammatory
Received 29 June 2016
Revised 14 August 2016
Accepted 19 August 2016
Available online xxxx
Keywords:
b-Carboline
P-selectin
Inhibitor
Anti-thrombosis
Anti-inflammation
response of mice and had a minimal effective dose of 20 nmol/kg. The decrease of serum TNF
a and IL-
8 of the treated mice was proposed to be the action mechanism of HMCEF inhibiting thrombosis and
inflammation. All data imply that HMCEF is a novel lead of P-selectin inhibitor.
Ó 2016 Published by Elsevier Ltd.
Vascular thrombosis is involved in the onset of diabetes melli-
tus, metabolic syndrome, atherosclerosis and hypertension,1 while
inflammation promotes the onset of cardiovascular disease and
tipping the haemostatic balance towards vascular thrombosis,
thereby inflammation and blood coagulation are linked.2 P-selectin
mediates the rolling of blood cells on the surface of the endothe-
lium, and triggers the adhesion of leukocytes to the platelets,
endothelial cells and other leukocytes at injury sites and inflamma-
tion tissues.3 The P-selectin level in the serum of the patients with
coronary heart disease is abnormally high, thus the decrease of
serum level of P-selectin provides a potential target for treating
vascular thrombosis and related diseases,4 and the discovery of
P-selectin inhibitors is of clinical importance.
b-Carbolines, such as b-carboline-3-carboxylic acids and
tetrahydro-b-carboline-3-carboxylic acids, are anti-thrombotic
active in vitro and in vivo.5–10 A derivative of b-carboline-3-car-
boxylic acid is recently presented as an anti-inflammatory agent,
and the anti-thrombotic activity of another derivative is correlated
with the down-regulation of P-selectin.11 These findings imply that
b-carboline should be a scaffold for designing novel lead of P-selec-
tin inhibitors that possess both anti-thrombotic and anti-inflam-
matory activities. As a going on interest in P-selectin inhibitors,
this Letter docked b-carboline-3-carboxylic acids, tetrahydro-b-
carboline-3-carboxylic acids and indoloquinolizines,9,10,12–17
totally 126 derivatives of our compound bank, into the active
pocket of P-selectin. In the integration of computational informa-
tion the binding energies were compared, the contributions of
the pharmacophores of 126 derivatives to binding energies were
estimated, the pharmacophores having significant contributions
to binding energies were selected, and (2-(3-(hydroxymethyl)-
9H-pyrido[3,4-b]indol-1-yl)ethyl)-L-phenylalanine (HMCEF) was
theoretically constructed. HMCEF was then also docked into the
active pocket of P-selectin, the binding energy, À7.76 kcal/mol, of
HMCEF was approved to be lower than those of all 126 derivatives.
In this context, the design, synthesis and evaluation of HMCEF as a
novel lead of P-selectin inhibitor having anti-thrombotic and anti-
inflammatory double actions are presented here.
In molecular docking the structure of P-selectin was treated as
rigid and prepared by AutoDock 4.0. The grid box dimensions were
set to 22.5 Å Â 30 Å Â 30 Å using a grid spacing of 0.375 Å for two
average structures. Energy-minimized 3D conformations of 126
derivatives were treated as flexible, prepared with AutoDock 4.0
and docked into the active sites of the average structure of P-selec-
tin (PDB: 1G1R). This allows automated docking of flexible ligands
to a rigid receptor with certain flexible residues. Lamarckian
genetic algorithm was used to find the appropriate binding posi-
tions, orientations, and conformations of 126 derivatives in the
binding site of the average structure. The global optimization
⇑
Corresponding authors.
(S. Peng).
0960-894X/Ó 2016 Published by Elsevier Ltd.