Discovery of N-amido-phenylsulfonamide derivatives as novel microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibitors

Article abstract of DOI:10.1016/j.bmcl.2021.127992

Our previous research showed that N-carboxy-phenylsulfonyl hydrazide (scaffold A) could reduce LPS-stimulated PGE₂ levels in RAW 264.7 macrophage cells by an inhibition of mPGES-1 enzyme. However, a number of scaffold A derivatives showed the drawbacks such as the formation of regioisomers and poor liver metabolic stability. In order to overcome these synthetic and metabolic problems, therefore, we decided to replace N-carboxy-phenylsulfonyl hydrazide (scaffold A) with N-carboxy-phenylsulfonamide (scaffold B) or N-amido-phenylsulfonamide frameworks (scaffold C) as a bioisosteric replacement. Among them, MPO-0186 (scaffold C) inhibited the production of PGE₂ (IC₅₀: 0.24 μM) in A549 cells via inhibition of mPGES-1 (IC₅₀: 0.49 μM in a cell-free assay) and was found to be approximately 9- and 8-fold more potent than MK-886 as a reference inhibitor, respectively. A molecular docking study theoretically suggests that MPO-0186 could inhibit PGE₂ production by blocking the PGH₂ binding site of mPGES-1 enzyme. Furthermore, MPO-0186 demonstrated good liver metabolic stability and no significant inhibition observed in clinically relevant CYP isoforms except CYP2C19. This result provides a potential starting point for the development of selective and potent mPGES-1 inhibitor with a novel scaffold.

Full text of DOI:10.1016/j.bmcl.2021.127992

Bioorg. Med. Chem. Lett. 41 (2021) 127992
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Discovery of N-amido-phenylsulfonamide derivatives as novel microsomal
prostaglandin E2 synthase-1 (mPGES-1) inhibitors
,
,
Misong Kima 1, Geuntae Kima 1, Minji Kanga, Dohyeong Koa, Yunchan Nama,
Chang Sang Moona, Heung Mo Kanga, Ji-Sun Shinb, Oliver Werzc, Kyung-Tae Leeb
,
,
*
Jae Yeol Leea
,d,*
a Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 02447, Republic of Korea
b Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 02447, Republic of Korea
c Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Philosophenweg 14, 07743 Jena, Germany
d KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Republic of Korea
A R T I C L E I N F O
A B S T R A C T
Keywords:
Our previous research showed that N-carboxy-phenylsulfonyl hydrazide (scaffold A) could reduce LPS-stimulated
PGE2 levels in RAW 264.7 macrophage cells by an inhibition of mPGES-1 enzyme. However, a number of scaffold
A derivatives showed the drawbacks such as the formation of regioisomers and poor liver metabolic stability. In
order to overcome these synthetic and metabolic problems, therefore, we decided to replace N-carboxy-phe-
nylsulfonyl hydrazide (scaffold A) with N-carboxy-phenylsulfonamide (scaffold B) or N-amido-phenyl-
sulfonamide frameworks (scaffold C) as a bioisosteric replacement. Among them, MPO-0186 (scaffold C)
Inflammation
PGE2
Bioisosteric replacement
Molecular docking
mPGES-1 inhibitor
inhibited the production of PGE2 (IC50: 0.24 μM) in A549 cells via inhibition of mPGES-1 (IC50: 0.49 μM in a cell-
free assay) and was found to be approximately 9- and 8-fold more potent than MK-886 as a reference inhibitor,
respectively. A molecular docking study theoretically suggests that MPO-0186 could inhibit PGE2 production by
blocking the PGH2 binding site of mPGES-1 enzyme. Furthermore, MPO-0186 demonstrated good liver meta-
bolic stability and no significant inhibition observed in clinically relevant CYP isoforms except CYP2C19. This
result provides a potential starting point for the development of selective and potent mPGES-1 inhibitor with a
novel scaffold.
Prostaglandin E2 (PGE2) is a widely distributed prostaglandin in the
human body and the principal prostaglandin of acute inflammation and
of chronic diseases such as rheumatoid arthritis and inflammatory bowel
disease.1–2 Therefore, the interference of PGE2 production may alleviate
inflammatory symptoms such as fever, arthritis, and inflammatory
pain.2 The biosynthetic pathway of PGE2 involves three sequential
enzymatic actions from arachidonic acid (AA): AA is released from the
membrane by phospholipase A2 (PLA2) and then converted to PGH2 by
cyclooxygenase 1 and 2 (COX-1 and COX-2), followed by the subsequent
isomerization of PGH2 into PGE2 by the terminal enzymes, prosta-
glandin E synthases (three isoforms: cPGES, mPGES-1 and mPGES-2).3–5
The successful modulation of PGE2 via the inhibition of one of three
sequential enzymatic actions may prevent or retard the inflammatory
symptoms. In order to avoid the gastrointestinal (GI) side effects of
nonsteroidal anti-inflammatory drugs (NSAIDs) inhibiting two isoforms
of COX, selective COX-2 inhibitors (coxibs) such as celecoxib and rofe-
coxib with lower risk of GI injury were developed.6 However, these se-
lective coxibs were revealed to increase the risk for cardiovascular
events due to the prevention of prostaglandin productions [in particular,
prostacyclin (PGI2)] of downstream of PGH2 as well as PGE2.7 Thus,
valdecoxib (Bextra®) and rofecoxib (Vioxx®) were withdrawn from the
market in 2004 and 2005, respectively.8 Meanwhile, microsomal pros-
taglandin E2 synthase-1 (mPGES-1) stimulated by inflammatory stimuli
catalyzes the terminal step in the biosynthesis of COX-2-derived PGE2
from PGH2.9 Thus, the selective inhibition of mPGES-1 is a safe thera-
peutic concept without any GI side effects compared to traditional
NSAIDs and coxibs. Therefore, various mPGES-1 inhibitors have been
reported in the literatures (Fig. 1).10 Unfortunately, drug development
* Corresponding authors at: Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 02447, Republic
of Korea (J.Y. Lee).
E-mail addresses: ktlee@khu.ac.kr (K.-T. Lee), ljy@khu.ac.kr (J.Y. Lee).
1
The contribution of the authors is equal.
https://doi.org/10.1016/j.bmcl.2021.127992
Received 2 January 2021; Received in revised form 11 March 2021; Accepted 19 March 2021
Available online 26 March 2021
0960-894X/© 2021 Elsevier Ltd. All rights reserved.

M. Kim et al.
Bioorganic & Medicinal Chemistry Letters 41 (2021) 127992
has been halted due to lack of potent inhibitors and a specific drug-
induced liver injury (DILI) of LY3023703.11 Only a few mPGES-1 in-
hibitors including GRC 27,864 have entered clinical trials.12–13 There-
fore, there is still an unmet need for the development of more potent and
safer mPGES-1 inhibitors.
chlorocarbonyl phenylsulfonamide 9, which was finally coupled with 4-
substituted aniline 10 in the presence DIPEA and 4-(dimethylamino)
pyridine (DMAP) as a catalyst to afford the desired N-amido-phenyl-
sulfonamide derivatives 13a-b.
The synthesized compounds were evaluated using EIA kit (Enzo Life
Sciences, Inc., Farmingdale, NY, USA) for their inhibitory activity
against PGE2 production in A549 human lung cancer cell lines.19 In
order to check that the suppressive effects of synthesized compounds on
PGE2 production could be attributable to non-specific cytotoxicity, we
examined the cytotoxic effect of synthesized compounds in A549 cells in
the presence of interleukin-1β (1 ng/mL) using MTT assays.20 None of
We had recently identified selective mPGES-1 inhibitors containing
N-carboxy-phenylsulfonyl hydrazide scaffold (scaffold A) for the
development of anti-inflammatory drugs (Fig. 2).14–17 Despite the good
inhibitory activities against PGE2 production and mPGES-1 enzyme (for
example, MPO-0063 in Table 1), major drawbacks of phenylsulfonyl
hydrazide derivatives were the inevitable formation of two regioisomers
depending on the reaction position (that is, two nitrogen atoms in
the compounds affected the viabilities of A549 cells at 1 μM concen-
15
phenylsulfonyl hydrazide scaffold)
and poor pharmacokinetic prop-
tration over 24 h. Therefore, all compounds were screened for their
erties such as liver microsomal stability and plasma stability (data of
MPO-0063 in Table 2). On the other hand, bioisosterism represents one
approach used by the medicinal chemist for the rational modification of
lead compounds into safer and more clinically effective agents via
replacement of functional groups or scaffolds.18 In order to overcome
these problems associated to phenylsulfonyl hydrazide scaffold, we
decided to investigate the effect of replacing N-carboxy-phenylsulfonyl
hydrazide (scaffold A) with N-carboxy-phenylsulfonamide (scaffold B)
and N-amido-phenylsulfonamide frameworks (scaffold C), respectively,
as shown in Fig. 2.
abilities to suppress PGE2 production in IL-1 β (1 ng/mL)-stimulated
A549 cells over 24 h.21 PF-4693627 (@ 1
μM) was used as a reference
inhibitor 22 and suppressed the PGE2 synthesis (IC50 = 0.52
μM under
our assay condition) as expected (Table 1 and Fig. 3). Their exact
IC50 values were obtained through three independent experiments and
summarized into Table 1. All synthesized compounds displayed good
inhibitory activities against PGE2 production (IC50 = 0.15 to 0.61 μM) in
the order of scaffold A ~ scaffold B > scaffold C. Compound 11b (MPO-
0144: scaffold A) was found to be the most potent inhibitor against PGE2
production (IC50 value of 0.15 μM). In the meanwhile, it was previously
In the present study, we examined the effects of synthetic compounds
featuring three unique scaffolds on PGE2 production, mPGES-1 activity,
CYP450 activity, liver microsomal stability, and plasma stability,
respectively (Fig. 2). In addition, a flexible molecular docking was also
carried out using the Molegro Virtual Docker (MVD) software package
for the comparison of binding modes of three unique scaffolds.
The representative synthesis of N-carboxy-phenylsulfonyl hydrazide
11, N-carboxy-phenylsulfonamide 12 and N-amido-phenylsulfonamide
frameworks 13 has been accomplished in three steps of reaction ac-
cording to our previously reported procedure as illustrated in Scheme
1.14–16 Phenylsulfonyl hydrazide 3a-b and phenylsulfonamide 8 were
prepared from the reaction of phenylsulfonyl chloride 1 with phenyl-
hydrazine 2 and benzylamine 7, respectively, in presence of triethyl-
amine (TEA) or diisopropylethylamine (DIPEA: Hünig’s base). Phenyl
chloroformate 6 was prepared in quantitative yield from the reaction of
phenol 4 with 0.5 equiv of triphosgene 5 in presence of Hünig’s base.
The coupling reaction of chloroformate 6 with phenylsulfonyl hydrazide
3 or phenylsulfonamide 8 afforded the desired N-carboxy-phenyl-
sulfonyl hydrazide 11a-b (previously reported kinetic product) 15 and N-
carboxy-phenylsulfonamide 12, respectively, in 73–90% yield. In the
case of N-amido-phenylsulfonamide derivatives 13a-b, phenyl-
sulfonamide 8 was treated with 0.5 equiv of triphosgene 5 to afford N-
reported that 11a (MPO-0063) and 12 (MPO-0112) also inhibited LPS-
induced PGE2 production with IC50 = 0.06 and 0.34 μM, respectively, in
RAW 264.7 macrophages.15,23
To further confirm whether compounds could act on human mPGES-
1, we carefully assessed their inhibitory activities against human cell-
free mPGES-1 using microsomes of IL-1β-stimulated A549 cells. PF-
4693627 and MK-886 were used as reference inhibitors and the potency
of PF-4693627 (IC50 = 3 nM) was almost consistent with the reported
value (Fig. 4A).22 Compound 11a (MPO-0063: scaffold A) carrying a
phenylsulfonyl hydrazide group showed an IC50 value of 0.61
μM.
However, compound 11b (MPO-0144: scaffold A) with 3-chloro sub-
stituent within N-phenyl ring completely failed to inhibit mPGES-1 up to
30
μM. Compound 12 (MPO-0112: scaffold B), N-carboxy-phenyl-
sulfonamide and a methylene analog of 11a, exhibited some reduced
activity with an IC50 value of 7.37 M compared to that of 11a. Com-
pound 13a (MPO-0180: scaffold C), N-amido analog of 12 (MPO-0112:
M). On the
μ
scaffold B), displayed strong loss of potency (IC50 = >30
μ
other hand, N-carboxy-phenylsulfonamide (or N-phenylcarbamate)
scaffold B of 12 (MPO-0112) exhibited poor liver microsomal stability
of all tested species and intermediate inhibition of hERG channel
(Table 2). So, we decided not to proceed the further investigation of
substituent effects on 12 (MPO-0112) activity. As shown in Fig. 1, the
Fig. 1. Previously reported mPGES-1 inhibitors.
2

M. Kim et al.
Bioorganic & Medicinal Chemistry Letters 41 (2021) 127992
Fig. 2. Structural modification of mPGE1-1 inhibitors based on their biological activities and in vitro pharmacokinetic parameters.
Table 1
Biological data and MolDock Scores of N-carboxy-phenylsulfonyl hydrazide, N-carboxy-phenylsulfonamide, and N-amido-phenylsulfonamide derivatives.
Entry (Lab. ID)
Scaffold
Cell viability (
μ
M) a
PGE2 IC50
(
μ
M) b, c
mPGES-1 IC50
(μ
M) b, d
MolDock Score e
11a (MPO-0063)
11b (MPO-0144)
12 (MPO-0112)
13a (MPO-0180)
13b (MPO-0186)
PF-4693637 h
scaffold A
scaffold A
scaffold B
scaffold C
scaffold C
> 1
> 1
> 1
>1
0.19 ± 0.05
0.15 ± 0.02
0.16 ± 0.01
0.61 ± 0.04
0.24 ± 0.05
0.61f
ꢀ 142.6
ꢀ 135.4
ꢀ 147.2
ꢀ 136.9
ꢀ 158.7
ꢀ 133.8
ꢀ 143.4
>30
7.37 g
>30
>1
0.49
>1
0.52 ± 0.04 i
0.003 j
MK-886 h
>1 g
2.10 k
3.90 g
aCytotoxicity of each compound using MTT assay; b Data are presented as the means ± SDs of three independent experiments; c The inhibition value of IL-1β (1 ng/mL)-
stimulated PGE2 production in A549 cells; d The mPGES-1 activity was evaluated under cell-free conditions by measuring PGE2 production; e MolDock score during
docking in the active site of mPGES-1 (PDB code: 4AL0) by using MVD 2012.5.5.0.; f Our previously reported data 14
;
g Our previously reported data 23
;
h Reference
inhibitors 22; i 16% inhibition at 1
μ
M under our assay condition (Figure 3); j This data is in agreement with the literature (IC50 = 3.0 nM)22
;
k The data of literature24
.
(glutathione) as a cofactor by the same software, which can automati-
cally detect cavities from protein surfaces. The putative active site of the
enzyme was defined to include residues within a 15 Å radius to this
cavity. The docking wizard of MVD 2012.5.5.0 was used to dock all
compounds together with PF-4693637 and MK-886 as mPGES-1 in-
hibitors for comparison. During the docking process, the top pose was
deposited for each ligand based on the MolDock score, which was
inserted in Table 1. The appropriate correlation between IC50 values and
MolDock Scores of synthesized compounds was found except PF-
4693637. Interestingly, PF-4693637 with the best potency (IC50 = 3
nM) displayed the lowest MolDock Score (-133.8), which would mean
that this compound might bind to an enzyme at a site other than the
active site including GSH and thus play a role as an allosteric inhibitor,
even though that any X-ray crystal structure of PF-4693637 and
mPGES-1 complex has not been reported until now. In order to confirm
this hypothesis, the further docking study was carried out using the
recently reported X-ray crystal structures and afforded the very similar
results, regardless of whether or not GSH is present in active site of
mPGES-1 (Table S1 in Supplementary data). 11b (MPO-0144) and 13a
(MPO-0180) displayed lower MolDock Score (-135.4 and ꢀ 136.9,
respectively), which was consistent with their weak potencies against
mPGES-1. When the oxygen of 12 (MPO-0112: scaffold B) was replaced
with NH in 13a (MPO-0180: scaffold C), the hydrogen bond energy was
increased but the total interaction energy was decreased regardless of
whether or not GSH is present in active site of mPGES-1 (Table S2,
Fig. S1, Fig. S2, and Supplementary data). Thus, 12 (MPO-0112: scaf-
fold B) showed higher MolDock score (-147.2) and better inhibitory
activity on mPGES-1 than 13a (MPO-0180: scaffold C). On the other
hand, the most active 13b (MPO-018b) showed the highest MolDock
score (-158.7), which supports that this compound could inhibit PGE2
production by blocking the active site of enzyme. In order to explain the
difference in the activity against mPGES-1 between 13a (MPO-0180;
Table 2
Preliminary ADME data of three scaffold compounds.
11a (MPO-0063)
12 (MPO-0112)
13b (MPO-0186)
1.0
a
PGI2 (IC50
)
0.25
9.60
μ
M
M
2.0
5.2
μ
M
M
μM
hERG (IC50
)
μ
μ
>10 μM
CYP450 activity (% of control activity at 10 μM)
CYP1A2
CYP2C9
CYP2C19
CYP2D6
CYP3A4
75.7
88.4
77.9
57.1
73.6
99.4
69.4
97.0
56.9
99.9
8.7
>100
>100
98.8
92.5
Liver microsomal stability (%remaining during 30 min at 1
μ
M)
human
dog
66.6
48.5
16.3
42.2
44.9
37.7
44.1
53.4
>100
86.4
74.5
79.0
rat
mouse
Plasma Stability (%remaining during 30 min at 10
μ
M)
human
<1
<1
>100
45.0
1.3
rat
2.1
a
Inhibitory effect on IL-1 β (1 ng/mL)-stimulated PGI2 production in A549
human lung cancer cell lines.
recently reported three mPGES-1 inhibitors have a linear or U-shaped
conformation compared to the compact conformation of MK-886 and
MF-63. Therefore, the introduction of additional three methylene units
in benzyloxyphenyl moiety of 13a, resulting in compound 13b (MPO-
0186: scaffold C), improved the activity (IC50 = 0.49 μM) as shown in
Fig. 4B. This compound 13b (MPO-0186) represents the most potent
mPGES-1 inhibitor within this study, which is 8-fold more active than
MK-886 as a competitive inhibitor (Table S1 of Supplementary data).
Molecular docking studies were performed to investigate and get a
better understanding of the observed SAR among these three scaffolds
by using the recently reported X-ray crystallized structure of mPGES-1
(PDB code: 4AL0). The docking studies were performed using Molegro
Virtual Docker (MVD) 2012.5.5.0 for Windows. First of all, we identified
one cavity with a volume 51 Å3 located in close proximity to GSH
IC50 = >30 μM) and 13b (MPO-0186; IC50 = 0.49 μM) according to the
length of methylene unit, the highest-ranking docking pose of each
compound was analyzed to further investigate the interaction of the
docked conformation within the active site. Before the analysis, Asp49,
3

M. Kim et al.
Bioorganic & Medicinal Chemistry Letters 41 (2021) 127992
Scheme 1. Reagents and conditions: (a) TEA, dry THF, 0 ℃ to rt, 3 h; (b) DIPEA, dry THF, 0 ℃, 2–4 h; (c) TEA, dry THF, rt, 2–4 h; (d) DIPEA, dry THF, rt, 2 h; (e)
DIPEA, DMAP (cat.), dry THF, rt, 12 h.
one nitrogen atom of the urea moiety also established a hydrogen bond
interaction with glutathione (3.35 Å) as shown in Fig. 5a-b. The sum of
hydrogen bond energy was found to be ꢀ 6.7 value. The other major
interaction was hydrophobic interactions between the ligand and
neighboring amino acids as shown in Fig. 5b. With respect to 13b (MPO-
0186), there were also major interactions between this ligand and
amino acids of the active site (Fig. 5c-d). One oxygen atom of the sulfone
moiety constituted two short and strong hydrogen bond interactions
with glutathione (2.96 Å) and Ser127 (2.74 Å). One nitrogen atom of the
urea moiety exhibited an additional hydrogen bond interaction with
glutathione (2.92 Å) as shown in Fig. 5c-d. The sum of hydrogen bond
energy was found to be ꢀ 7.5 value. The other major interaction was
hydrophobic interactions between the ligand and neighboring amino
acids as shown in Fig. 5d. The total interaction energy between 13b
(MPO-0186) and mPGES-1 was greater (-194.46 kcal/mol) than that
(-168.64 kcal/mol) of 13a (MPO-0180). Therefore, it was rationalized
that 13b (MPO-0186) exhibited more potency than 13a (MPO-0180) by
establishing stronger hydrogen bonds and hydrophobic interactions
with mPGES-1 enzyme. On the other hand, 11a (MPO-0063: scaffold A)
don’t have a flexible four-methylene unit to afford a compact confor-
mation and exhibited lower MolDock Scrore than that of 13b (MPO-
0186). However, the inhibitory activity of 11a (MPO-0063) against m-
PGES-1 was found to be equipotent as that of that of 13b (MPO-0186).
Based on the detailed analysis of docking results (Supplementary data),
11a (MPO-0063) exhibited additional hydrogen bond interactions with
GSH (cofactor) by using the other nitrogen atom of hydrazide moiety
and thus could have stronger interaction with GSH than 13b (MPO-
0186), capable of strongly inhibiting m-PGES-1 enzyme.
Fig. 3. Effect of synthesized compounds on IL-1 β (1 ng/mL)-stimulated
PGE2 production in A549 human lung cancer cell lines. Cells were treated with
only IL-1 β (1 ng/ml) or along with the compounds (10, 100, or 1000 nM) for
24 h. Levels of PGE2 in culture media were quantified using EIA kit. PF-
4693627 (1
μ
M) was used as a reference inhibitor. #p < 0.05 versus the control
group; ***p < 0.001 versus the IL-1 β -stimulated group; significant differences
between groups were determined using ANOVA and Dunnett’s post-hoc test.
Asp126 and Ser127 were found to be key residues which are reported in
the literature.25 Fig. 5a-d represent the docking poses of 13a (MPO-
0180) and 13b (MPO-0186), respectively. In the case of 13a (MPO-
0180), one oxygen atom of the sulfone moiety constituted two hydrogen
bond interactions with glutathione (3.19 Å) and Arg126 (2.97 Å), and
The major side effects of COX-2 inhibitors on the cardiovascular
system could be associated with reduced PGI2 synthesis.26 Thus, three
4

M. Kim et al.
Bioorganic & Medicinal Chemistry Letters 41 (2021) 127992
Fig. 4. Effect of PF-4693627 as a reference inhibitor (A) and compound 13b (MPO-0186) (B) on mPGES-1 activity. Microsomal preparation of IL-1β-stimulated
A549 cells were preincubated with indicated concentrations of compounds or vehicle (DMSO) for 15 min on ice. After reactions for 1 min with substrate, PGE2
production was measured by EIA kits. Remaining activity (% of control) are showed mean ± SDs (n = 3). ***p < 0.001 vs. the control group; significant differences
between groups were determined using ANOVA and Dunnett’s post-hoc test.
Fig. 5. 3D and 2D docking mode of MPO-0180 (a-b) and MPO-0186 (c-d) into the active site of mPGES-1 enzyme. All hydrogen atoms were omitted for the graphic
simplicity. Each pose was represented by stick form and colored by element and glutathione as a cofactor was represented by ball-and-stick red colored form.
Hydrogen bonds were depicted as blue dashed lines and hydrophobic interactions were depicted as red dashed lines.
scaffold compounds were further screened for the inhibitory effect on
the PGI2 production in A549 cancer cells. As shown in Table 2, com-
pound 11a (MPO-0063) strongly reduced the level of PGI2 with IC50
hERG IC50 indicats that from an early drug discovery perspective,
compounds with low potency can be progressed on the basis of a low risk
of causing a QTc increase: high (IC50 < 1 μM), intermediate (1 μM <
value of 0.25
μ
M. However, 12 (MPO-0112) and 13b (MPO-0186)
IC50 < 10
μ
M), and low (IC50 > 10
μ
M).28 Compounds 11a (MPO-0063)
could weekly reduce the level of PGI2 with IC50 values of 2.0 and 1.0
μM,
and 13b (MPO-0186) showed low potency against hERG potassium
respectively. Therefore, 12 (MPO-0112) and 13b (MPO-0186) exerted
ca. 8- and 4-fold selective inhibitory activities against PGE2 over PGI2
production in A549 cancer cells, respectively, when treated with IL-1β.
We also explored the brief drug-like properties of three scaffold
compounds through in vitro ADME study using the reported standard
protocol.27 Preliminary results of in vitro ADME study were listed in
Table 2. Firstly, positive and negative predictive values of absolute
channels with IC50 values of 9.6 and > 10
μM, respectively, compared to
12 (MPO-0112) with IC50 value of 5.2
μM. Next, five CYP450 isozymes
were selected to gain a preliminary understanding of the interaction
between each compound and the CYP450 isozymes using the standard
procedure.29–30 In this CYP450 assay at 10
μM concentration of each
compound, all compounds showed lower inhibition of four CYP450
isozymes (IC50 ≥ 10 μM) except CYP2C19. 13b (MPO-0186) exhibited
5

M. Kim et al.
Bioorganic & Medicinal Chemistry Letters 41 (2021) 127992
high inhibition of only CYP2C19 (8.7% remaining activity of enzyme),
which is a liver enzyme that acts on at least 10% of drugs in current
clinical use.31 We also explored the in vitro metabolic stability in mouse,
rat, dog, and human liver microsomes using a single point metabolic
assay.29,32 Briefly, each compound was incubated at a concentration of
Korea (NRF) grant funded by the Korea government (MSIT) (No.
2019R1F1A1059332 and No. 2020R1A5A2019413).
Appendix A. Supplementary data
1.0
μ
M with 1.0 mg/mL protein at 37 ◦C for 30 min. 11a (MPO-0063)
Supplementary data to this article can be found online at https://doi.
org/10.1016/j.bmcl.2021.127992.
and 12 (MPO-0112) exhibited low to intermediate liver metabolic sta-
bility depending on the animal (16.3 to 66.6% remaining). However,
13b (MPO-0186) showed good metabolic stability with more than 75%
remaining in liver microsomes of all species as shown in Table 2. The in
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Declaration of Competing Interest
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The authors declare that they have no known competing financial
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the work reported in this paper.
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This work was supported by the National Research Foundation of
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