Structure-based design of 2-aminopyridine oxazolidinones as potent and selective tankyrase inhibitors

Article abstract of DOI:10.1021/ml4003315

Aberrant activation of the Wnt pathway has been implicated in the development and formation of many cancers. TNKS inhibition has been shown to antagonize Wnt signaling via Axin stabilization in APC mutant colon cancer cell lines. We employed structure-based design to identify a series of 2-aminopyridine oxazolidinones as potent and selective TNKS inhibitors. These compounds exhibited good enzyme and cell potency as well as selectivity over other PARP isoforms. Co-crystal structures of these 2-aminopyridine oxazolidinones complexed to TNKS reveal an induced-pocket binding mode that does not involve interactions with the nicotinamide binding pocket. Oral dosing of lead compounds 3 and 4 resulted in significant effects on several Wnt-pathway biomarkers in a three day DLD-1 mouse tumor PD model.

Full text of DOI:10.1021/ml4003315

Letter
pubs.acs.org/acsmedchemlett
Structure-Based Design of 2‑Aminopyridine Oxazolidinones as
Potent and Selective Tankyrase Inhibitors
Hongbing Huang,*,† Angel Guzman-Perez,† Lisa Acquaviva,§ Virginia Berry,‡ Howard Bregman,†
Jennifer Dovey,§ Hakan Gunaydin,∥ Xin Huang,∥ Liyue Huang,‡ Doug Saffran,§ Randy Serafino,§
Steve Schneider,∥ Cindy Wilson,§ and Erin F. DiMauro†
‡
§
∥
†Departments of Medicinal Chemistry; Pharmacokinetics and Drug Metabolism; Oncology Research; and Molecular Structure,
Amgen Inc., 360 Binney Street, Cambridge, Massachusetts 02142, United States
S
* Supporting Information
ABSTRACT: Aberrant activation of the Wnt pathway has
been implicated in the development and formation of many
cancers. TNKS inhibition has been shown to antagonize Wnt
signaling via Axin stabilization in APC mutant colon cancer
cell lines. We employed structure-based design to identify a
series of 2-aminopyridine oxazolidinones as potent and
selective TNKS inhibitors. These compounds exhibited good
enzyme and cell potency as well as selectivity over other PARP
isoforms. Co-crystal structures of these 2-aminopyridine
oxazolidinones complexed to TNKS reveal an induced-pocket
binding mode that does not involve interactions with the
nicotinamide binding pocket. Oral dosing of lead compounds 3 and 4 resulted in significant effects on several Wnt-pathway
biomarkers in a three day DLD-1 mouse tumor PD model.
KEYWORDS: Wnt pathway, tankyrase inhibitor, cancer, PARP, 2-aminopyridine oxazolidinone
he canonical Wnt pathway regulates the stability of the
lines (SW480, DLD-1).13,14 In this research, two main
structural classes of small molecule TNKS inhibitors were
utilized: those that occupy the highly conserved nicotinamide
pocket of the catalytic PARP domain, as represented by
XAV939,15 and those that bind to the induced pocket of the
enzymes, as exemplified by IWR1/2.16,17 The induced pocket is
not present in apo TNKS proteins and only becomes accessible
upon the binding of the inhibitors.18 Residues forming the
induced pocket are less conserved among other PARP family
members. Therefore, this novel binding mode provides a
unique opportunity to achieve broader selectivity over other
PARP family members and NAD-utilizing enzymes.19,20 Herein,
we describe a structure-based approach to identify novel 2-
aminopyridine oxazolidinones as potent and selective TNKS
inhibitors that bind in the induced pocket.
The compounds presented in this study were examined for
their ability to inhibit the activity of TNKS1 using enzyme
assays with recombinant TNKS catalytic domains. Three
cellular assays in two different APC mutant CRC cell lines
were developed to aid evaluation of TNKS inhibitors. First, a
proximal cellular assay measured the accumulation of Axin2
protein in SW480 cells as a result of TNKS inhibition. Second,
a central cellular assay assessed the degradation of total β-
T
transcriptional coactivator β-catenin.1 The level of active
β-catenin is tightly controlled by a complex of proteins known
as the destruction complex, which consists of the scaffolding
protein Axin, kinases GSK3β and CK1α, and the tumor
suppressor protein APC.2 In the absence of Wnt stimulation,
cytosolic β-catenin is constitutively phosphorylated and
targeted for degradation by the ubiquitin/proteosome pathway.
Interaction of a Wnt ligand with cell surface receptors results in
breakdown of the β-catenin destruction complex, leading to the
accumulation of nuclear β-catenin and transcription of Wnt
target genes.3,4
Aberrant activation of the Wnt pathway has been implicated
in the development and formation of many cancers; for
example, APC mutations have been observed in >80% of
sporadic colorectal cancers (CRC).5,6 Blocking the aberrant
Wnt signaling has been shown to be effective in stopping
growth of cultured colon cancer cells.7,8 Considering the
increasing number of Wnt-driven cancers, intervention of the
Wnt signaling pathway with small molecules has the potential
to be an effective cancer treatment.9−11
Tankyrases belong to the poly-ADP-ribose polymerase
(PARP) family.12 The two isoforms, TNKS1 and TNKS2,
share overlapping function and a high degree of homology.
Seminal work by researchers at Novartis and University of
Texas, Southwestern demonstrated that pharmacological
inhibition of TNKS1/2 antagonizes canonical Wnt signaling
via Axin stabilization in certain APC mutant colon cancer cell
Received: August 27, 2013
Accepted: October 21, 2013
© XXXX American Chemical Society
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Figure 1. (A) Structure and activity of compounds 1 and 2. (B) Cocrystal structure of TNKS1 complexed with 1. (C) Cocrystal structure of TNKS1
complexed with 2. (D) Overlay of cocrystal structures of 1 and 2.
catenin (TBC) in SW480 cells. Finally, a transcriptional Wnt-
reporter assay (STF), driven by multimerized TCF binding
sites in DLD-1 cells quantified the effect of TNKS inhibition on
downstream Wnt signaling events.
occupies the induced pocket, with N1 hydrogen bonded to
Asp1198, and the amino group hydrogen bonded to Gly1196
(Figure 1C).
An overlay of the cocrystal structures of 1 and 2 bound to
TNKS1 inspired a hypothesis that replacing the labile
aminoquinazoline amide of 1 with a 2-aminopyridine might
increase stability in plasma while maintaining two critical H-
bond interactions with the protein (Figure 1A). We envisioned
that the aminopyridine moiety would serve as a simplified
mimic of the aminoquinazoline group in 2. Positioning an
aromatic pyrimidinyl group at the 3-positon would engage the
important π-stacking interaction with His1201, as observed
with the quinoline ring of 1. Gratifyingly, compound 3 showed
good TNKS inhibitory activity while demonstrating excellent
selectivity over PARP1/2 (Table 1). In cellular assays, 3
promoted accumulation of Axin (Axin EC50 = 0.709 μM) and
inhibited β-catenin accumulation (TBC IC50 = 0.233 μM) and
Wnt-reporter gene transcription (STF IC50 = 0.096 μM).
Furthermore, compound 3 was stable in human and rat liver
microsomes (HLM/RLM Clint = 33/48 μL/min/mg).
Recently we discovered that oxazolidinone 1 binds to
TNKS1 in the induced pocket in a manner similar to that
described for IWR1/2 (Figure 1A).21 The key ligand−protein
interactions include three hydrogen bonds: the carbonyl group
of the oxazolidinone interacts with Tyr1213; the carbonyl
group of the amide with Asp1198; the CH at the 6-position of
the quinoline is associated with the backbone carbonyl of
Gly1196. In addition, the quinoline group engages in a π-
stacking interaction with His1201 of the D-loop (Figure 1B).
While 1 showed good enzymatic activity, it exhibited moderate
rat plasma stability. Metabolite identification studies revealed
that the amide is prone to hydrolysis in both rat and mouse
plasma.
During the course of our lead-optimization work on 1, high-
throughput screening identified compound 2 as a potent and
novel TNKS inhibitor. A cocrystal structure of 2 complexed
with TNKS1 reveals that 2 occupies both the conserved
nicotinamide pocket and the induced pocket in a dual-binding
mode, similar to that recently described for other TNKS
inhibitors.22 The dihydroquinolinone moiety resides in the
nicotinamide pocket with the carbonyl group hydrogen
bonding to Ser1221 and the nitrogen engaging in a hydrogen
bond interaction with Gly1185. The aminoquinazoline group
Consistent with previously disclosed observations,13 potency
was significantly improved by replacing the central phenyl ring
with a saturated cyclohexyl group. The stereochemistry of the
cyclohexyl ring significantly impacts the potency. For example,
the trans-isomer 4 demonstrated greatly improved enzymatic
and cellular potency over 3, while the cis-isomer 5 was less
potent. The substituent at the 3-position of the pyridine ring
B
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Table 1. SAR of 2-Aminopyridine Oxazolidinones
a
b
Values represent the mean of at least of two experiments. ND = not determined.
Figure 2. X-ray cocrystal structures: (A) 3 bound to TNKS1 and (B) 4 bound to TNKS1.
proved to be important for potency. While compound 7
showed only moderate enzymatic activity, introduction of a
small polar group (−CN) in compound 6 led to enhanced
potencies in the enzyme and cellular assays. Although highly
efficient, 6 had reduced potency relative to lead compound 4,
which contains the aromatic pyrimidine substituent incorpo-
rated in the initial design for π-stacking to His1201.
dihedral angle with respect to the pyridine ring; while the trans-
cyclohexyl group of 4 is perpendicular to the pyridine ring, a
conformation that enables the cyclohexyl group to fill the
hydrophobic pockets formed by neighboring residues (Ser1186,
Phe1188, and Ala1202). These hydrophobic interactions are
not present in the 3/TNKS1 structure, which may account for
the increased potency of 4 relative to 3.
To understand the structural basis for the potency observed
with compounds 3 and 4, cocrystal structures of both
compound 3 and 4 complexed with TNKS1 were obtained.
The structures were resolved at 2.3 and 2.0 Å, respectively
(Figure 2). The two compounds bind to TNKS1 in a similar
fashion. The carbonyl group of the oxazolidinone is hydrogen
bonded to Tyr1213. As intended, the aminopyridine interacts
with Asp1198 and Gly1196 through two hydrogen bond
interactions. The pyrimidine ring is close to be being coplanar
with the aminopyridine ring and engages in a π-stacking
interaction with His1201 of the D-loop. The major difference
between the two structures is the position of the central ring of
the inhibitors. The central phenyl ring of 3 has a ∼45 degree
Since the initial lead 2 was a potent kinase inhibitor and the
2-aminopyridine motif is known to interact with the hinge
region of many kinases,23 we screened 3 and 4 against a broad
panel of kinases (Ambit KINOMEscan).24 Both compounds
exhibited weak kinase inhibitory activity in this panel. Only 1
out of the 100 kinases had percent-of-control (POC) < 30 at 1
μM of 4.25 Compounds 3 and 4 were also screened for
genotoxicity potential. Intriguingly, while 3 tested positive in a
microAmes assay with and without S9 activation, 4 was negative
under the same assay conditions. Compound 4 is also highly
selective over 13 GPCRs (EC50, IC50 > 48.5 μM),26 hERG
(IC50 = 10.9 μM), and BSEP (IC50 = 11 μM).
C
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Table 2. Pharmacokinetic Parameters of Compounds 3 and 4
a
a
b
rat iv PK
rat po PK
t1/2
mouse po PK
c
d
e
dose
CL
(L/h/kg)
Vss
(L/kg)
t1/2
(h)
dose
Cmax
(μM)
F
dose
Cmax
(μM)
t1/2
(h) AUC (μM·h)
compd
(mg/kg)
(mg/kg)
(h) AUC (μM·h) (%)
(mg/kg)
3
4
0.5
0.5
0.52
0.75
2.32
2.85
4.3
3.6
2.0
2.0
0.37
0.45
4.6
2.9
2.71
1.98
29
33
30
30
7.88
6.09
3.7
63.3
36.3
3.5
a
b
Pharmacokinetic parameters following administration of compounds 3 or 4 in male Sprague−Dawley rats: 2 animals per study. Pharmacokinetic
c
d
parameters following administration of compound 3 or 4 in male Mouse_CD1: 3 animals per study. Dosed as a solution in DMSO. Dosed in 1%
Tween 80/2% HPMC/97% water/MSA pH 2.2. Dosed in 10.0% Pluronic F68/30.0% HPBCD/60.0% water/MSA pH 2.5.
e
Figure 3. Subcutaneous tumors were established in athymic nude mice using DLD-1 human colon cancer cell line. Animals were dosed for 3 days
and then tumors (for protein analysis) and plasma (for PK) were collected 14 h after the last dose. (A) The effect of compounds 3 and 4 on
accumulation of Axin2 protein in human tumor xenograft model. (B) The effect of compounds 3 and 4 on inhibition of downstream reporter gene
transcription.
In light of their excellent enzyme and cellular potencies and
good selectivity, compounds 3 and 4 were evaluated in rodent
pharmacokinetic (PK) studies. Selected PK data is summarized
in Table 2. Upon intravenous (iv) dosing to rats, 3 and 4
demonstrated moderate clearance and volumes of distribution
with elimination half-lives of 4.3 and 3.6 h, respectively. Both
compounds exhibited reasonable plasma exposure and
bioavailability when dosed orally in rats at 2.0 mg/kg. Oral
dosing in mice at 30 mg/kg also resulted in a good plasma
exposure.
Compounds 3 and 4 were evaluated in a pharmacodynamic
(PD) assay in DLD-1 human tumor xenograft mice. Oral b.i.d.
dosing of 3 at 200 mg/kg for three days resulted in significant
Axin accumulation and inhibition of STF reporter activity with
associated terminal plasma concentration of approximately 22.1
μM (Figure 3). In addition, 3 also inhibited Wnt-target gene
(Axin2 and TCF7) expression at the same dose (Supporting
Information). More potent lead 4 promoted Axin accumulation
and STF reporter activity inhibition at a lower dose (50 mg/kg,
oral b.i.d.) with associated terminal plasma concentration of
0.12 μM.
killing activity of 4 in a standard three day DLD-1 cell
proliferation assay (10% FBS, nuclear counting with cellomics
Array scan) was only moderate (IC50 = 3 μM), and recent data
suggests that DLD-1 tumor growth is not sensitive to
pharmacological TNKS inhibition.28
Compound 4 is an optimized representative of this highly
potent and selective structural series with potency, selectivity,
and pharmacokinetic properties suitable to explore the
pharmacological potential of TNKS inhibition in the context
of future mouse tumor xenograft efficacy studies.
Compound 3 was prepared in a convergent fashion as
described in Scheme 1. Suzuki coupling between pyridinyl
boronic acid 8 and 2-bromopyrimidine afforded aryl bromide 9,
which was subsequently converted to boronic acid pinacol ester
10 in good yield. A copper catalyzed coupling of commercially
available 11 with 1,4-diiodobenzene provided aryl iodide 12.
Suzuki coupling of 10 with 12 followed by aminolysis of the 2-
fluoropyridine then furnished compound 3 in high yield.
Compounds 4−7 were prepared using the routes illustrated
in Scheme 2. Reductive amination between commercial amino
alcohol (S)-13 and 1,4-cyclohexanedione monoethylene acetal
provided compound 14. Triphosgene-mediated cyclization and
subsequent deprotection of the ketal using TFA afforded
ketone 15 in 81% yield over 3 steps. Notably the chiral integrity
remained intact during the process. Ketone 15 was converted
to triflate 16 under standard conditions. Suzuki coupling of 16
with 2-aminopyridine-3-boronic acid pinacol ester followed by
Pd/C catalyzed hydrogenation provided a mixture of cis- and
trans-isomers of 7 (∼1:1 ratio). The two isomers were
separated by HPLC. Bromination of 7 under standard
condition afforded intermediate 17. Stille coupling of 17 with
2-(tributylstannyl)pyrimidine provided compound 4. Pd-
In order to ascertain general utility for extended
pharmacodynamic studies, compound 4 was dosed orally for
̈
eight days to naıve athymic nude mice. At 50 mg/kg b.i.d.
continuous dosing, compound 4 was well tolerated. This is
encouraging as this was the efficacious dose in the DLD-1
tumor PD study, and the mean unbound plasma concentration
levels were comparable between the two studies.27
Despite robust in vivo Axin accumulation and inhibition of
STF in a three day DLD-1 mouse tumor xenograft assay,
compounds 3 and 4 were not advanced to multiweek DLD-1
tumor xenograft efficacy studies because the observed cell-
D
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Letter
a
both enzyme and cell assays and exhibited high selectivity over
PARP1/2. Twice daily oral dosing of 4 at 50 mg/kg promoted
accumulation of Axin and inhibition of Wnt-dependent reporter
activity in a three day DLD-1 mouse tumor PD model. This
Scheme 1. Synthesis of Compound 3
̈
dosing schedule was also well tolerated in naıve athymic nude
mice for eight continuous days. Compound 4 is expected to
serve as an excellent tool compound to thoroughly investigate
the effects of selective pharmacological inhibition of TNKS in
various APC mutant CRC lines and disease relevant tumor
models.
ASSOCIATED CONTENT
■
S
* Supporting Information
Experimental details, biological assays, kinase selectivity, and X-
ray crytstallographic information. This material is available free
of charge via the Internet at http://pubs.acs.org.
Accession Codes
The PDB accession codes for the X-ray cocrystal structures of
TNKS1 + 2, TNKS1 + 3, and TNKS1 + 4 are 4N3R, 4N4T,
and 4N4V, respectively.
a
Reagents: (a) 2-bromopyrimidine, PdCl2(dppf), aq. Na2CO3,
dioxane, 100 °C, 76%; (b) PdCl2(dppf), KOAc, bis(pinacolato)-
diboron, 79%; (c) 1,4-diiodobenzene, CuI, K3PO4, MeNH-
(CH2)2NHMe, dioxane, μW, 140 °C, 61%; (d) PdCl2(dppf), aq.
Na2CO3, dioxane, 100 °C, 62%; (e) NH3, DMSO, 83%.
AUTHOR INFORMATION
■
Corresponding Author
*(H.H.) Tel: 617-444-5197. E-mail: hongbing.huang@amgen.
com.
Notes
catalyzed cyanation of 17 using Zn(CN)2 furnished compound
6.
The authors declare no competing financial interest.
We have described the design, synthesis, and biological
evaluation of a novel series of aminopyridine oxazolidinones as
potent and selective TNKS inhibitors that bind in the induced
pocket. Compound 4 demonstrated excellent TNKS potency in
ABBREVIATIONS
■
APC, adenomatous polyposis coli; CK1α, casein kinase 1α;
GSK3β, glycogen synthase kinase 3β; STF, super TOP-flash
a
Scheme 2. Synthesis of Compounds 4-7
a
Reagents: (a) 1,4-cyclohexanedione monoethylene acetal, NaBH(OAc)3, DCM, rt; (b) triphosgene; (c) TFA, 81% (3 steps); (d) PhNTf2,
LiHMDS, THF, 71%; (e) 2-aminopyridine-5-boronic acid pinacol ester, PdCl2(dppf), aq. Na2CO3, dioxane, 100 °C, 93%; (f) H2, Pd/C, 39%; (g)
NBS, DCM, 100%; (h) 2-(tributylstannyl)pyrimidine, Pd(Ph3P)4, LiCl, CuI, DMF, 47%; (i) Pd(Ph3P)4, Zn(CN)2, DMF, 60%.
E
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between tankyrase-2 and a potent Wnt-signaling inhibitor. J. Med.
Chem. 2010, 53, 5352−5355.
REFERENCES
■
(1) Gordon, M. D.; Nusse, R. Wnt signaling: multiple pathways,
multiple receptors, and multiple transcription factors. J. Biol. Chem.
2006, 281, 22429−22433.
(2) Kimelman, D.; Xu, W. beta-Catenin destruction complex: insights
and questions from a structural perspective. Oncogene 2006, 25, 7482−
7491.
(3) Yochum, G. S.; Sherrick, C. M.; Macpartlin, M.; Goodman, R. H.
A beta-catenin/TCF-coordinated chromatin loop at MYC integrates 5′
and 3′ Wnt responsive enhancers. Proc. Natl. Acad. Sci. U.S.A. 2010,
107, 145−150.
(4) Mirando, A. J.; Maruyama, T.; Fu, J.; Yu, H. M.; Hsu, W. beta-
Catenin/cyclin D1 mediated development of suture mesenchyme in
calvarial morphogenesis. BMC Dev. Biol. 2010, 10, 116.
(5) Korinek, V.; Barker, N.; Morin, P. J.; van Wichen, D.; de Weger,
R.; Kinzler, K. W.; Vogelstein, B.; Clevers, H. Constitutive
transcriptional activation by a beta-catenin-Tcf complex in APC−/−
colon carcinoma. Science 1997, 275, 1784−1787.
(6) Powell, S. M.; Zilz, N.; Beazer-Barclay, Y.; Bryan, T. M.;
Hamilton, S. R.; Thibodeau, S. N.; Vogelstein, B.; Kinzler, K. W. APC
mutations occur early during colorectal tumorigenesis. Nature 1992,
359, 235−237.
(7) Tetsu, O.; McCormick, F. Beta-catenin regulates expression of
cyclin D1 in colon carcinoma cells. Nature 1999, 398, 422−426.
(8) van de Wetering, M.; Sancho, E.; Verweij, C.; de Lau, W.; Oving,
I.; Hurlstone, A.; van der Horn, K.; Batlle, E.; Coudreuse, D.; Haramis,
A. P.; Tjon-Pon-Fong, M.; Moerer, P.; van den Born, M.; Soete, G.;
Pals, S.; Eilers, M.; Medema, R.; Clevers, H. The beta-catenin/TCF-4
complex imposes a crypt progenitor phenotype on colorectal cancer
cells. Cell 2002, 111, 241−250.
(9) Huang, H.; Acquaviva, L.; Berry, V.; Bregman, H.; Chakka, N.;
O’Connor, A.; Dimauro, E. F.; Dovey, J.; Epstein, O.; Grubinska, B.;
Goldstein, J.; Gunaydin, H.; Hua, Z.; Huang, X.; Huang, L.; Human, J.;
Long, A.; Newcomb, J.; Patel, V. F.; Saffran, D.; Serafino, R.;
Schneider, S.; Strathdee, C.; Tang, J.; Turci, S.; White, R.; Yu, V.;
Zhao, H.; Wilson, C.; Martin, M. W. Structure-based design of potent
and selective CK1γ inhibitors. ACS Med. Chem. Lett. 2012, 3, 1059−
1064.
(10) Hua, Z.; Huang, X.; Bregman, H.; Chakka, N.; Dimauro, E. F.;
Doherty, E. M.; Goldstein, J.; Gunaydin, H.; Huang, H.; Mercede, S.;
Newcomb, J.; Patel, V. F.; Turci, S. M.; Yan, J.; Wilson, C.; Martin, M.
W. 2-Phenylamino-6-cyano-1H-benzimidazole-based isoform selective
casein kinase 1 gamma (CK1gamma) inhibitors. Bioorg. Med. Chem.
Lett. 2012, 22, 5392−5395.
(16) Narwal, M.; Venkannagari, H.; Lehtio, L. Structural basis of
selective inhibition of human tankyrases. J. Med. Chem. 2012, 55,
1360−1367.
(17) Haikarainen, T.; Venkannagari, H.; Narwal, M.; Obaji, E.; Lee,
H. W.; Nkizinkiko, Y.; Lehtio, L. Structural basis and selectivity of
tankyrase inhibition by a Wnt signaling inhibitor WIKI4. PLoS One
2013, 8, e65404.
(18) Gunaydin, H.; Gu, Y.; Huang, X. Novel binding mode of a
potent and selective tankyrase inhibitor. PLoS One 2012, 7, e33740.
(19) Lund, F. E. Signaling properties of CD38 in the mouse immune
system: enzyme-dependent and -independent roles in immunity. Mol.
Med. 2006, 12, 328−333.
(20) Gharehbaghi, K.; Sreenath, A.; Hao, Z.; Paull, K. D.; Szekeres,
T.; Cooney, D. A.; Krohn, K.; Jayaram, H. N. Comparison of
biochemical parameters of benzamide riboside, a new inhibitor of IMP
dehydrogenase, with tiazofurin and selenazofurin. Biochem. Pharmacol.
1994, 48, 1413−1419.
(21) Bregman, H.; Chakka, N.; Guzman-Perez, A.; Gunaydin, H.; Gu,
Y.; Huang, X.; Berry, V.; Liu, J.; Teffera, Y.; Huang, L.; Egge, B.;
Mullady, E. L.; Schneider, S.; Andrews, P. S.; Mishra, A.; Newcomb, J.;
Serafino, R.; Strathdee, C. A.; Turci, S. M.; Wilson, C.; Dimauro, E. F.
Discovery of novel, induced-pocket binding oxazolidinones as potent,
selective, and orally bioavailable tankyrase inhibitors. J. Med. Chem.
2013, 56, 4320−4342.
(22) Bregman, H.; Gunaydin, H.; Gu, Y.; Schneider, S.; Wilson, C.;
DiMauro, E. F.; Huang, X. Discovery of a class of novel tankyrase
inhibitors that bind to both the nicotinamide pocket and the induced
pocket. J. Med. Chem. 2013, 56, 1341−1345.
(23) Cui, J. J.; Tran-Dube, M.; Shen, H.; Nambu, M.; Kung, P. P.;
Pairish, M.; Jia, L.; Meng, J.; Funk, L.; Botrous, I.; McTigue, M.;
Grodsky, N.; Ryan, K.; Padrique, E.; Alton, G.; Timofeevski, S.;
Yamazaki, S.; Li, Q.; Zou, H.; Christensen, J.; Mroczkowski, B.;
Bender, S.; Kania, R. S.; Edwards, M. P. Structure based drug design of
crizotinib (PF-02341066), a potent and selective dual inhibitor of
mesenchymal-epithelial transition factor (c-MET) kinase and ana-
plastic lymphoma kinase (ALK). J. Med. Chem. 2011, 54, 6342−6363.
(24) Human Kinome. http://kinase.com/human/kinome/ (accessed
June 2013).
(25) DDR1 had a POC of 18% in the presence of 1 μM compound 4.
(26) The panel of GPCRs includes receptors 5HT1A, ADRA1A,
ADORA2, CB1, CCR2, CXCR2, D2, H1, M1, MOR, NK1, SST4, and
ADRB1.
(27) At 100 mg/kg b.i.d. dosing, significant animal health concerns
(cold, lethargic, hunched, dehydrated, and diarrhea) were noted at day
8, prior to sacrifice.
(11) Waaler, J.; Machon, O.; Tumova, L.; Dinh, H.; Korinek, V.;
Wilson, S. R.; Paulsen, J. E.; Pedersen, N. M.; Eide, T. J.; Machonova,
O.; Gradl, D.; Voronkov, A.; von Kries, J. P.; Krauss, S. A novel
tankyrase inhibitor decreases canonical Wnt signaling in colon
carcinoma cells and reduces tumor growth in conditional APC mutant
mice. Cancer Res. 2012, 72, 2822−2832.
(28) Lau, T.; Chan, E.; Callow, M.; Waaler, J.; Boggs, J.; Blake, R. A.;
Magnuson, S.; Sambrone, A.; Schutten, M.; Firestein, R.; Machon, O.;
Korinek, V.; Choo, E.; Diaz, D.; Merchant, M.; Polakis, P.; Holsworth,
D. D.; Krauss, S.; Costa, M. A novel tankyrase small-molecule inhibitor
suppresses APC mutation-driven colorectal tumor growth. Cancer Res.
2013, 73, 3132−3144.
(12) Lehtio, L.; Chi, N. W.; Krauss, S. Tankyrases as drug targets.
FEBS J. 2013, 280, 3576−3593.
(13) Huang, S. M.; Mishina, Y. M.; Liu, S.; Cheung, A.; Stegmeier, F.;
Michaud, G. A.; Charlat, O.; Wiellette, E.; Zhang, Y.; Wiessner, S.;
Hild, M.; Shi, X.; Wilson, C. J.; Mickanin, C.; Myer, V.; Fazal, A.;
Tomlinson, R.; Serluca, F.; Shao, W.; Cheng, H.; Shultz, M.; Rau, C.;
Schirle, M.; Schlegl, J.; Ghidelli, S.; Fawell, S.; Lu, C.; Curtis, D.;
Kirschner, M. W.; Lengauer, C.; Finan, P. M.; Tallarico, J. A.;
Bouwmeester, T.; Porter, J. A.; Bauer, A.; Cong, F. Tankyrase
inhibition stabilizes axin and antagonizes Wnt signalling. Nature 2009,
461, 614−620.
(14) Chen, B.; Dodge, M. E.; Tang, W.; Lu, J.; Ma, Z.; Fan, C. W.;
Wei, S.; Hao, W.; Kilgore, J.; Williams, N. S.; Roth, M. G.; Amatruda, J.
F.; Chen, C.; Lum, L. Small molecule-mediated disruption of Wnt-
dependent signaling in tissue regeneration and cancer. Nat. Chem. Biol.
2009, 5, 100−107.
(15) Karlberg, T.; Markova, N.; Johansson, I.; Hammarstrom, M.;
Schutz, P.; Weigelt, J.; Schuler, H. Structural basis for the interaction
F
dx.doi.org/10.1021/ml4003315 | ACS Med. Chem. Lett. XXXX, XXX, XXX−XXX