Design and synthesis of novel dasatinib derivatives as inhibitors of leukemia stem cells

Article abstract of DOI:10.1016/j.bmcl.2018.01.011

We used the concept of bioisosteres to design and synthesize a novel series of dasatinib derivatives for the treatment of leukemia. Unfortunately, most of the dasatinib derivatives did not show appreciable inhibition against leukemia cell lines K562 and H

Full text of DOI:10.1016/j.bmcl.2018.01.011

Bioorganic & Medicinal Chemistry Letters xxx (2018) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Design and synthesis of novel dasatinib derivatives as inhibitors
of leukemia stem cells
a,
Hui-ying Li b,c, Ding-Di He a,b,c, Xiu-Juan Zhao a,b, Tong-Yan Sun a,b, Quan Zhang a, Cui-Gai Bai b, , Yue Chen
⇑
⇑
a The State Key Laboratory of Medicinal Chemical Biology, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Pharmacy, and Tianjin
Key Laboratory of Molecular Drug Research, Nankai University, Tianjin 300353, PR China
b High-throughput Molecular Drug Discovery Center, Tianjin international Joint Academy of BioMedicine, Tianjin 300457, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
We used the concept of bioisosteres to design and synthesize a novel series of dasatinib derivatives
for the treatment of leukemia. Unfortunately, most of the dasatinib derivatives did not show appre-
ciable inhibition against leukemia cell lines K562 and HL60. However, acrylamide compound 2c
had comparable inhibitory activity with dasatinib against K562 cells (IC50 = 0.039 nM vs. 0.069 nM).
And amide compound 2a and acrylamide compound 2c also had comparable inhibitory activity with
dasatinib against the leukemia cell line HL60 (IC50 = 0.25 nM and 0.26 nM vs. 0.11 nM). Against the
leukemia progenitor cell line KG1a, triazole compounds 15a and 15d–15f and oxadiazole compounds
24a–24d were more potent than dasatinib. In particular, the hydroxyl compounds 15a and 24a were
Received 22 November 2017
Revised 5 January 2018
Accepted 11 January 2018
Available online xxxx
Keywords:
Dasatinib derivatives
Bioisosteres
Triazole
Oxadiazole
about 64 and 180 fold more potent than dasatinib against KG1a cells (IC50 = 0.14
lM and 0.05 lM vs.
8.98 M). Compounds 15a and 24a also inhibited colony formation in MCF-7 cells and inhibited cell
l
migration in the cell wound scratch assay in B16BL6 cells. Moreover, hydroxyl compounds 15a and
24a had low toxicity in vivo.
Colony formation
Cell migration
Ó 2018 Elsevier Ltd. All rights reserved.
Dasatinib is a second-generation, orally available, potent, and
multi-targeted inhibitor of Bcr-Abl and Src family kinases.1,2
Dasatinib is effective in imatinib-resistant wild type and mutant
BCR-ABL cell lines, except in those carrying the T315I muta-
tion.3–7 Dasatinib also has high selectivity for normal hematopoi-
etic cells and leukemia cells.8 When dasatinib was used in
conjunction with bone marrow transplantation, however, many
mutations emerged, including T315I/A, F317L/I/C/V, V299L
(IC50 > 15 nM), Y253F, E255 K/V and G250E.9–14 Dasatinib also
fails to eliminate the quiescent chronic myeloid leukemia
(CML) stem cell compartment.15
Bioisosterism is a very important strategy for drug design in
medicinal chemistry, and 1,3,4-oxadiazole and 1,2,3-triazole are
considered to be bioisosteres of the amide group. 1,3,4-Oxadiazole
and 1,2,3-triazole rings have special biological properties and these
moieties have been successfully used in multi-targeted drugs,
including the anti-cancer drug, zibotentan.16
pounds was evaluated in the leukemia cell lines K562 and HL60,
and the leukemia progenitor cell line, KG1a. Lead compounds were
further evaluated by the colony forming assay in MCF-7 cells and
the cell wound scratch assay in B16BL6 cells. Preliminary toxicity
was also discussed.
Dasatinib derivatives were prepared using the sequences shown
in Schemes 1–5.
Firstly, acid amide compounds 2a–2d were synthesized
(Scheme 1). Dasatinib was treated with phthalimide to provide
compound 1, which was deprotected to provide amine compound
2a. Amine compound 2a was then converted to compounds 2b–2d.
Treatment with CS2 under basic conditions afforded isothiocyanate
compound 2b, treatment with acryloyl chloride provided the allyl
amide compound 2c and treatment with chloroacetyl chloride gave
the chloroethyl amide compound 2d.
Triazole ring compounds 15a–15f were synthesized as shown in
Schemes 2 and 3. Boc protection of amine compound 3 provided
compound 4, which was converted to iodide compound 5 using
N-iodosuccinimide (NIS). Iodide compound 5 was reacted with
trimethylsilylacetylene to provide compound 6, which was then
deprotected to give alkyne compound 7. Azide compound 9 and
alkyne compound 7 were treated with Cu2O nanoparticles to give
the triazole ring compound 10 using click chemistry. The Boc
Here, a series of dasatinib derivatives, containing oxadiazole
and triazole rings, was synthesized and the activity of the com-
⇑
Corresponding authors.
E-mail addresses: baicuigai@tjab.org (C.-G. Bai), yuechen@nankai.edu.cn (Y. Chen).
These authors contributed equally to this work.
c
https://doi.org/10.1016/j.bmcl.2018.01.011
0960-894X/Ó 2018 Elsevier Ltd. All rights reserved.
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H.-y. Li et al. / Bioorganic & Medicinal Chemistry Letters xxx (2018) xxx–xxx
Scheme 1. Reagents and conditions: (a) PPh3, phthalimide, DIAD, THF, r.t, 88%; (b) N2H2ÁH2O, EtOH, 78 °C, 72%; (c) DCC, CS2, CH2Cl2, r.t, 52%; (d) acryloyl chloride, Et3N,
CH2Cl2, r.t, 49%; (e) chloroacetyl chloride, Et3N, CH2Cl2, r.t, 55%;
protecting group was then removed from compound 10 to provide
compound 11. Condensation of compounds 11 and 12 gave
compound 13, which was treated with different amines to provide
compounds 15a and 15b. Triazole amine compound 15c was
prepared from compound 15b by removal of the Boc group.
Compounds 15d–15f were synthesized using the same procedures
for synthesis of acid amide compounds 2b–2d, respectively.
1,3,4-Oxadiazole compounds 24a–24e were prepared as shown
in Schemes 4 and 5. Amine compound 16 was treated with com-
pound 12 to afford pyrimidine 17, which was condensed with dif-
ferent amine by condensation reaction to provide compounds 19a
and 19b. Compounds 19a and 19b were treated with hydrazine
solution to provide carbohydrazide compounds 20a and 20b,
which were treated with chloride 21 to give compounds 22a and
22b. Compounds 22a and 22b were then converted to compounds
23a and 23b. Deprotection of compounds 23a and 23b gave com-
pounds 24a and 24b. Compound 24b was then converted to com-
pounds 24c–24e, using the procedures described for the synthesis
of compounds 2b–2d.
was more potent than dasatinib (IC50 = 8.98 lΜ) whereas com-
pounds 2a, 2c and 2d (IC50 = 25.39, 12.88, and 13.56 lΜ, respec-
tively) were less potent than dasatinib.
Inhibitory activities of triazoles 15a and 15c–15f were reduced
170–530-fold against K562 cells and 35–150-fold against HL60
cells whereas inhibitory activities were enhanced 4–64-fold
against leukemia progenitor cells KG1a. Amongst the triazoles,
isothiocyanate compound 15d had the lowest inhibitory activity
against K562 and HL60 cells (IC50 = 36.48 and 16.57 nM, respec-
tively) and compounds 15a, 15c, 15e and 15f had comparable inhi-
bitory activities (IC50 = 14.14, 11.73, 15.09 and 17.65 nM,
respectively, against K562 cells and 4.19, 4.08, 5.46 and 9.82 nΜ,
respectively, against HL60 cells). In KG1a cells, amine compound
15c had the poorest inhibitory activity (IC50 = 2.06
pound 15a had best inhibitory activity (IC50 = 0.14
pounds 15d–15f had comparable inhibitory activities (IC50 = 0.32,
0.25 and 0.45 Μ).
lΜ) and com-
lM). Com-
l
The IC50 values of the oxadiazole compounds against both K562
and HL60 cell lines were at least an order of magnitude higher than
that of dasatinib. Against KG1a cells, compound 24e (IC50 = 9.75
Most of the dasatinib derivatives did not noticeably inhibit the
growth of K562 and HL60 cells, but both triazole and oxadiazole
compounds were more potent than dasatinib against leukemia
progenitor cell line KG1a (Table 1).
For compounds 2a–2d, inhibitory activities did not increase. In
K562 cells, the IC50 values of compounds 2a–2d were 0.72, 3.77,
0.039 and 1.67 nM, respectively. The inhibitory activity of acry-
l
l
Μ) had comparable inhibitory activity to dasatinib (IC50 = 8.98
Μ). Compounds 24a–24d (IC50 = 0.05, 0.68, 0.15, and 0.11 Μ,
l
respectively) were more potent than dasatinib. It is noteworthy
that compound 24a was about 180-fold more potent than
dasatinib.
Dasatinib, and compounds 15a and 24a, significantly and dose-
dependently decreased the formation of colonies in MCF-7 cells,
compared with the control group (Fig. 1). The high dose of com-
pound 15a was more potent than dasatinib and the high dose of
compound 24a was comparable with dasatinib. Compounds 15a
and 24a could thus inhibit the growth of cancer stem cells, and
compound 15a was more potent than compound 24a.
lamide compound 2c was comparable to that of dasatinib (IC50
=
0.069 nM). In HL60 cells, the activities of compounds 2a and 2c
were very similar to that of dasatinib (IC50 = 0.25 nM and 0.26 vs.
0.11 nM). Isothiocyanate compound 2b (IC50 = 1.07 nM) had com-
parable inhibitory activity to that of compound 2d (IC50 = 0.86
nM). In KG1a cells, isothiocyanate compound 2b (IC50 = 1.96 lΜ)
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H.-y. Li et al. / Bioorganic & Medicinal Chemistry Letters xxx (2018) xxx–xxx
3
Scheme 2. Reagents and conditions: (a) (Boc)2O, Et3N, DMAP, THF, r.t, 4 h, 64%; (b) NIS, THF, r.t, 2 h, 70%; (c) CuI, PdCl2(PPh3)2, Trimethylsilylacetylene, Et3N, THF, rt, 12 h,
60%; (d) K2CO3, MeOH, r.t, 0.5 h, 98%; (e) NaNO2, HCl, NaN3, H2O, 3 h, 0 °C; (f) Cu2O nanoparticles, CH3CN:H2O, r.t, overnight, 86%; (g) HCl, DCM, 4 h, 96%; (h) NaH, THF, À20 °C,
86%; (i) DIPEA, 1,4-dioxane, 5–18 h, for 15a: 88% and for 15b: 90%.
Scheme 3. Reagents and conditions: (a) TFA, CH2Cl2, r.t, 80%; (b) DCC, CS2, CH2Cl2, r.t, 41%; (c) acryloyl chloride, Et3N, CH2Cl2, r.t, 47%; (d) chloroacetyl chloride, Et3N, CH2Cl2, r.
t, 37%.
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H.-y. Li et al. / Bioorganic & Medicinal Chemistry Letters xxx (2018) xxx–xxx
Scheme 4. Reagents and conditions: (a) Cs2CO3, DMF, 0 °C, 5 min, r.t, 8 h, 82%; (b) DIPEA, 1,4-dioxane, 103 °C, 5.5 h, for 19a: 89% and for 19b: 90%; (c) EtOH, N2H4ÁH2O, 78 °C,
for 20b: 59%; (d) Et3N, r.t, 5 h, for 22a: 73% and for 22b: 80%; (e) TsCl, K2CO3, r.t, for 23a: 76% and for 23b: 60%; (f) for: 9a: TBAF, THF, 3 h, r.t, 96%; for: 9b: TFA, CH2Cl2, 2 h,
83%.
Compared with control group, migration was inhibited in
B16BL6 cells treated with dasatinib and compounds 15a and 24a
(Fig. 2). The inhibitory effects of compounds 15a and 24a were
comparable with the positive control dasatinib, and inhibition of
24a was stronger than that of 15a.
The survival rate of mice, dosed with dasatinib, and compounds
15a and 24a (all 200 mg/kg) once for 2 weeks, was 100% (Fig. 3).
When the dose was increased, mice treated with compounds 15a
and 24a also survived, demonstrating the low toxicity of com-
pounds 15a and 24a.
and 180-fold more potent than dasatinib against KG1a cells. We
speculate, therefore, that compounds 15a and 24a may be able to
eradicate stem cells in CML. Compounds 15a and 24a inhibited col-
ony formation in MCF-7 cells and also inhibited cell migration in
the cell wound scratch assay in B16BL6 cells. Compounds 15a
and 24a had low toxicity in vivo and provided a possibility for
the treatment of CML.
Acknowledgments
In summary, we have designed and synthesized novel dasatinib
derivatives and evaluated their in vitro activity against three differ-
ent leukemia cell lines (K562, HL60 and KG1a). Compared with
dasatinib, all of the newly synthesized triazole and oxadiazole
derivatives showed good efficacy in the leukemia progenitor cell
line KG1a. In particular, compounds 15a and 24a were about 64-
This work was supported by the National Natural Science Foun-
dation of China (NSFC) (No. 81573282 to Y.C.), the National Science
Fund for Distinguished Young Scholars (No. 81625021 to Y.C.) and
the Natural Science Foundation of Tianjin (No. 16JCQNJC13800 to
CG.B.).
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H.-y. Li et al. / Bioorganic & Medicinal Chemistry Letters xxx (2018) xxx–xxx
5
Scheme 5. Reagents and conditions: (a) DCC, CS2, CH2Cl2, r.t, 37%; (b) acryloyl chloride, Et3N, CH2Cl2, r.t, 39.7%; (c) chloroacetyl chloride, Et3N, CH2Cl2, r.t, 35%.
Table 1
Inhibitory effects of dasatinib derivatives in K562, HL60 and KG1a cells.
Compound
Dasatinib
X
R
K562 IC50 (nΜ)
0.069 0.004
HL60 IC50 (nΜ)
0.11 0.02
KG1a IC50
8.98 0.03
(lΜ)
2a
0.72 0.35
0.25 0.06
25.39 0.35
2b
2c
3.77 1.72
1.07 0.55
0.26 0.13
1.96 0.18
0.039 0.009
12.88 2.59
2d
1.67 0.22
0.86 0.08
13.56 0.18
15a
15c
15d
14.14 2.64
11.73 3.41
36.48 10.69
4.19 0.78
4.08 0.61
16.57 2.86
0.14 0.03
2.06 0.20
0.32 0.10
15e
15.09 2.99
5.46 0.38
0.25 0.06
15f
17.65 1.62
9.82 2.88
0.45 0.07
24a
24b
(0.23 0.07) * 103
(0.26 0.05) * 103
(0.15 0.08) * 103
(0.11 0.04) * 103
0.05 0.008
0.68 0.06
24c
24d
(1.81 0.63) * 103
(0.15 0.04) * 103
(1.42 0.06) * 103
(0.16 0.03) * 103
0.15 0.08
0.11 0.05
24e
(3.06 0.23) * 103
(2.12 0.29) * 103
9.75 0.11
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H.-y. Li et al. / Bioorganic & Medicinal Chemistry Letters xxx (2018) xxx–xxx
Fig. 1. The effects of 15a and 24a on the formation of clones in MCF-7 cell. Cells were administered with positive medicine Dasatinib (7.5
lM), compounds 15a (Low: 0.96
l
M, Middle: 1.90 M, High: 3.80 M) and 24a (Low: 0.68 M, Middle: 1.35 M, High: 2.70
l
l
l
l
l
M) for 10 days. *P < 0.05, **P < 0.01, compared with the control group.
Fig. 2. The effects of compounds 15a and 24a on the migration of B16BL6 cells. Cells were administered with positive medicine Dasatinib (8.13
M) and 24a (1.43 M) for 2 days.
lM), compounds 15a (0.82
l
l
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7
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Fig. 3. The toxicity of compounds 15a and 24a on mice. Mice were orally
administered with positive medicine Dasatinib (200 mg/kg), compounds 15a
(200 mg/kg, 500 mg/kg and 1000 mg/kg) and 24a (200 mg/kg, 500 mg/kg and
1000 mg/kg) once and observed for 14 days.
A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at https://doi.org/10.1016/j.bmcl.2018.01.011.
Please cite this article in press as: Li H.-y., et al. Bioorg. Med. Chem. Lett. (2018), https://doi.org/10.1016/j.bmcl.2018.01.011