Quinolinoneacetic acid derivatives as novel glutathione S-transferase P1-1 inhibitors: Insights into the interaction modes by molecular modeling

Article abstract of DOI:10.1007/s00044-011-9806-y

Glutathione S-transferase P1-1 (GSTP1-1, EC 2.5.1.18) is generally conceived to be an important player in the acquired resistance of tumor to anticancer agents, thus a series of quinolinoneacetic acid derivatives were synthesized and their inhibitory effe

Full text of DOI:10.1007/s00044-011-9806-y

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2012) 21:2823–2826
DOI 10.1007/s00044-011-9806-y
ORIGINAL RESEARCH
Quinolinoneacetic acid derivatives as novel glutathione
S-transferase P1-1 inhibitors: insights into the interaction modes
by molecular modeling
•
Jian Wang Shao-Jie Wang Dan-Dan Song
•
•
•
Yong-Kui Jing Mao-Sheng Cheng
Received: 5 November 2010 / Accepted: 6 October 2011 / Published online: 22 October 2011
Ó Springer Science+Business Media, LLC 2011
Abstract Glutathione S-transferase P1-1 (GSTP1-1, EC
2.5.1.18) is generally conceived to be an important player in the
acquired resistance of tumor to anticancer agents, thus a series
of quinolinoneacetic acid derivatives were synthesized and
their inhibitory effects on GSTP-1 were tested in this study.
Interestingly, it was found that some compounds showed
remarkable inhibitory effect on GSTP-1 activity. Furthermore,
molecular docking study was conducted to provide the binding
modes of quinolinoneacetic acid derivatives on GSTP1-1
activity. In summary, we present the discovery of a series of
quinolinoneacetic acid compounds as inhibitors of GSTP1-1
and their interaction modes toward GSTP1-1 binding site.
catalyzes the conjugation of glutathione with a variety of
exogenous and endogenous electrophiles (Townsend and
Tew 2003). It is over-expressed in malignant tissues and is
considered to play an important role in the acquired
resistance of tumor to antitumor agents (Di Ilio et al., 1987;
Di Ilio et al., 1988; Eimoto et al., 1988; Harrison et al.,
1989; Howie et al., 1990; Moscow et al., 1989; Rangana-
than and Tew, 1991; Shiratori et al., 1987). Thus, GSTP1-1
inhibitors are extremely beneficial for overcoming the
chemotherapy resistance in tumor cells.
Quinolinoneacetic acid derivatives were actually firstly
discovered to be a new class of aldose reductase inhibitors
for diabetes treatment by our lab (Wang et al., 2007, 2009).
Interestingly, they also showed their ability to inhibit
GSTP1-1 activity in human leukemia HL-60 cell lysates,
and some of them even showed similar inhibitory effect
like ethacrynic acid, which is a well-known GSTP-1
inhibitor. The molecular modeling studies further elucidate
the binding modes of these derivatives on GSTP1-1
activity. Collectively, we found that some quinolinone-
acetic acid derivatives have great potential to be further
developed into the novel chemotherapeutic sensitizers.
Keywords Glutathione S-transferase P1-1 ꢀ
Quinolinoneacetic acid ꢀ Chemotherapy resistance ꢀ
Molecular modeling
Introduction
Glutathione S-transferase P1-1 (GSTP1-1, EC 2.5.1.18),
a member of phase II detoxification enzyme family,
J. Wang ꢀ S.-J. Wang ꢀ M.-S. Cheng (&)
Key Laboratory of Structure-Based Drug Design & Discovery
of Ministry of Education, School of Pharmaceutical Engineering,
Shenyang Pharmaceutical University, Shenyang 110016,
People’s Republic of China
Materials and methods
Synthesis of chemicals
e-mail: mscheng@syphu.edu.cn
In this article, 35 compounds were discussed. Their chem-
ical structures are summarized in Table 1. Starting from
substituted aniline, the final products were synthesized via
addition, hydrolysis, cyclization, alkylation, condensation,
and hydrolysis. The synthetic details were described pre-
viously when we firstly reported their aldose reductase
inhibitory activities (Wang et al., 2009) (Scheme 1).
D.-D. Song ꢀ Y.-K. Jing
School of Life Sciences & Biopharmaceutical Sciences,
Shenyang Pharmaceutical University, Shenyang 110016,
People’s Republic of China
Y.-K. Jing
Mount Sinai School of Medicine, One Gustave L. Levy Place,
New York, NY 10029, USA
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Med Chem Res (2012) 21:2823–2826
Cell culture and GSTP1-1 activity assay
Table 1 The GSTP1-1 activity inhibition by quinolinoneacetic acids
derivatives
O
HL-60 cells growing as a suspension culture, were main-
tained in RPMI 1640 medium supplemented with 100 U/ml
penicillin, 100 lg/ml streptomycin, 1 mM glutamine and
10% heat-inactivated fetal bovine serum, and cells were
incubated in a humidified atmosphere with 5% CO2 in air
at 37°C. Exponentially growing cells (3 9 106) were
washed twice with PBS, resuspended in 300 ll of 100 mM
potassium phosphate buffer (pH 6.8), sonicated for 10 s at
4°C, and centrifuged at 14000 rpm for 30 min at 4°C. The
supernatant was used for GSTP1-1 activity assay. GSTP1-1
activity was determined according to the reported method
(Habig et al., 1974). In brief, CDNB and GSH were used as
substrates, and the linear increase in absorption at 340 nm,
caused by conjugation of GSH (1 mM) with CDNB
(1 mM) in HL-60 cell lysate with or without presence of
compounds VI-01–VI-35 (20 lM), was measured. An
extinction coefficient of 9.6 mM-1 cm-1 was used to cal-
culate GSTP1-1 activity expressed as micromoles per
minute per milligram of protein. The activity inhibition rate
was calculated as:
R1
R3
N
R2
COOH
Compd.
Substituents
R1 R2
GSTP1-1
activity inhibition
rate (%)
R3
Ethacrynic acid
VI01
VI02
VI03
VI04
VI05
VI06
VI07
VI08
VI09
VI10
VI11
VI12
VI13
VI14
VI15
VI16
VI17
VI18
VI19
VI20
VI21
VI22
88.6
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
CH3 3-CH3
39.06
17.53
15.36
8.10
CH3 3,5-di-CH3
CH3 2-OC2H5
CH3 2,3-di-OCH3
CH3 3,5-di-OCH3
CH3 4-CH3
32.28
46.80
75.57
22.85
31.08
31.46
0.85
CH3 3-OH
CH3 4-F
CH3 3,4-OCH2O
CH3 4-OCH3
CH3 3,4,5-tri-OCH3
CH3 4-N(CH3)2
CH3 2-OCH3
Vc ꢁ Vt
Inhibition rate ¼
ꢂ 100%
13.18
4.72
Vc
where Vc represents GSTP1-1 activity of control group; Vt
represents GSTP1-1 activity of treated group.
CH3 2,5-di-OCH3
CH3 4-OC2H5
CH3 2,3,4-tri-OCH3
CH3 2,4-di-OCH3
5.44
42.44
1.57
Molecular modeling
11.73
19.71
67.59
59.13
23.58
20.68
Cl
Cl
Cl
Cl
2-OC2H5
4-CH3
The crystal structure of human GSTP in complex with
ethacrynic acid (PDB entry code: 2GSS) (Oakley et al.,
1997) was used. The protein was prepared with
4-OC2H5
2,3,4-tri-OCH3
˚
Fred_receptor and the active site box was extended 4.0 A
CH3 2-OCH3-3,4-
OCH2O
around the co-crystallized ligand. The compounds in this
paper were submitted to OMEGA v. 2.1.0 to generate
conformers for use in FRED. The carboxylate groups were
deprotonated to imitate physiological conditions. OMEGA
was run as keeping conformations within 5.0 kcal/mol
VI23
VI24
VI25
VI26
VI27
VI28
VI29
VI30
VI31
VI32
VI33
VI34
VI35
H
CH3 2-Cl
51.87
45.59
27.93
17.53
25.76
14.39
5.68
H
Cl
CH3
H
3-CH3
H
H
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
4-OCH3
4-OC2H5
3-OCH3
2,3,4-tri-OCH3
3,5-OCH3
4-Br
˚
(e_window), having an rmsd cutoff of 0.6 A and keeping
H
1,000 output conformations in accordance with recom-
¨
mendation by Bostrom et al. (2003). The docking protocols
H
H
were setup using the programs default settings. The gen-
erated poses were ranked using the implemented chem-
gauss3 scoring function.
H
23.82
28.17
20.68
4.23
H
H
4-Cl
H
H
H
3,4-OCH2O
4-F
34.70
16.08
Results and discussion
H
The structures of quinolinoneacetic acid derivatives and
their inhibitory activities on GSTP1-1 are shown in
Table 1. These compounds inhibited GSTP1-1 activity at
the concentration of 20 lM, with the inhibition rate of
75.57% for the most effective compound VI07. To our
knowledge, this is the first observation that quinolinone-
acetic acids exhibit GSTP1-1 inhibitory activity. Therefore,
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Med Chem Res (2012) 21:2823–2826
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Scheme 1 Synthesis of target compounds. Starting from substituted aniline, the final products were synthesized via addition, hydrolysis,
cyclization, alkylation, condensation, and hydrolysis
Fig. 1 Binding interactions of the most active compound VI-07 and
GSTP1-1. a Chemical structure of VI-07. b Binding of VI-07.
c Binding of VI-07 in the active site of GSTP1-1. The important
amino acid residues are labeled with name and number. Hydrogen
bonds are indicated in green (Color figure online)
the present finding reveals some significant novel mole-
cules along with structural insights using molecular dock-
ing studies.
docking study that the a, b-unsaturated carbonyl group is
crucial for covalent binding with glutathione. Moreover,
chemical variation could be made in aromatic rings to
optimize the structural properties toward higher activity.
The over-expression of GSTP1-1 in tumor cells has been
shown to be related with the tumor resistance to chemo-
therapeutic drugs, thus GSTP-1 inhibitor will be advanta-
geous for chemotherapeutic sensitizer development.
Therefore, there is urgent need to discover some potent
GSTP1-1 inhibitors for developing the chemotherapeutic
sensitizers in the antitumor treatment. As shown in the
study, quinolinoneacetic acid derivatives are potent
GSTP1-1 inhibitors. Moreover, the elucidation of the
As illustrated, Fig. 1 is a docking model of inhibitors in
complex with GSTP1-1, in which inhibitor V-07 forms
hydrogen bonds with Tyr7, Trp38, Tyr108, and Gly205.
The hydroxyl, carbonyl, and carboxyl groups are essential
for its interactions with the receptor.
In regards to the structural difference as well as activity,
it is speculated that these compounds might bind into the
H-site and conjugate with glutathione through Michael
addition to behave like suicide inhibitors for GSTP1-1.
And conclusion could be drawn from the molecular
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Harrison DJ, Kharbanda R, Bishop D, McLelland LI, Hayes JD
(1989) Glutathione S-transferase isoenzymes in human renal
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optimization in the novel GSTP1-1 inhibitor development.
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Conclusion
In summary, we discovered that some quinolinoneacetic
acid derivatives are novel GSTP1-1 inhibitors by pharma-
cological test as well as the molecular docking analysis,
which provides the information necessary to find new
GSTP1-1 inhibitors to restore chemotherapeutic sensitivity
in resistant tumor cells.
Acknowledgments The authors would like to thank OpenEye Sci-
entific Software Inc. for allowing us to utilize their software for this
study.
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