3-Aroyl-1,4-diarylpyrroles Inhibit Chronic Myeloid Leukemia Cell Growth through an Interaction with Tubulin

Article abstract of DOI:10.1021/acsmedchemlett.7b00022

We designed 3-aroyl-1,4-diarylpyrrole (ARDAP) derivatives as potential anticancer agents having different substituents at the 1- or 4-phenyl ring. ARDAP compounds exhibited potent inhibition of tubulin polymerization, binding of colchicine to tubulin, and cancer cell growth. ARDAP derivative 10 inhibited the proliferation of BCR/ABL-expressing KU812 and LAMA84 cells from chronic myeloid leukemia (CML) patients in blast crisis and of hematopoietic cells ectopically expressing the imatinib mesylate (IM)-sensitive KBM5-WT or its IM-resistant KBM5-T315I mutation. Compound 10 minimally affected the proliferation of normal blood cells, indicating that it may be a promising agent to overcome broad tyrosine kinase inhibitor resistance in relapsed/refractory CML patients. Compound 10 significantly decreased CML proliferation by inducing G2/M phase arrest and apoptosis via a mitochondria-dependent pathway. ARDAP 10 augmented the cytotoxic effects of IM in human CML cells. Compound 10 represents a robust lead compound to develop tubulin inhibitors with potential as novel treatments for CML.

Full text of DOI:10.1021/acsmedchemlett.7b00022

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Letter
3-Aroyl-1,4-diarylpyrroles Inhibit Chronic Myeloid
Leukemia Cell Growth through an Interaction with Tubulin
Giuseppe La Regina, Ruoli Bai, Antonio Coluccia, Valeria Famiglini, Sara Passacantilli, Valentina Naccarato,
Giorgio Ortar, Carmela Mazzoccoli, Vitalba Ruggieri, Francesca Agriesti, Claudia Piccoli, Tiziana Tataranni,
Marianna Nalli, Andrea Brancale, Stefania Vultaggio, Ciro Mercurio, Mario Varasi, Concetta Saponaro,
Sara Sergio, Michele Maffia, Addolorata Maria Luce Coluccia, Ernest Hamel, and Romano Silvestri
ACS Med. Chem. Lett., Just Accepted Manuscript • Publication Date (Web): 26 Apr 2017
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II, ASL - University of Salento
Hamel, Ernest; National Cancer Institute at Frederick, Screening
Technologies Branch, Developmental Therapeutics Program
Silvestri, Romano; Sapienza Università di Roma, Chimica e Tecnologie del
Farmaco
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3-Aroyl-1,4-diarylpyrroles Inhibit Chronic Myeloid Leukemia Cell
Growth through an Interaction with Tubulin
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†
‡
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Giuseppe La Regina, Ruoli Bai, Antonio Coluccia, Valeria Famiglini, Sara Passacantilli, Valentina
†
†
≠
≠
≠
Naccarato, Giorgio Ortar, Carmela Mazzoccoli, Vitalba Ruggieri, Francesca Agriesti, Claudia Pic-
Tiziana Tataranni, Marianna Nalli, Andrea Brancale, Stefania Vultaggio, Ciro Mercurio,
Mario Varasi, Concetta Saponaro, Sara Sergio, Michele Maffia, Addolorata Maria Luce Coluccia,
,
≠ æ
≠
†
∞
◆
◆
coli,
○
○
○
○
◆
,
†
‡
Ernest Hamel, and Romano Silvestri,*
†
Institut Pasteur Italy - Cenci Bolognetti Foundation, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università
di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
‡
Screening Technologies Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, Fred-
erick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
21702, USA
≠
Laboratory of Pre-clinical and Translational Research, IRCCS-CROB, Referral Cancer Center of Basilicata, Rionero in Vul-
ture, Italy
æ
Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
∞
Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB,
UK
○
Clinical Proteomics, Polo Oncologico Giovanni Paolo II, ASL - University of Salento, Piazza Muratore 1, 73100 Lecce, Italy
◆
Experimental Therapeutics Unit, IFOM-the FIRC Institute of Molecular Oncology Foundation, Via Adamello 16, I-20139
Milano, Italy
KEYWORDS cancer, tubulin, chronic myeloid leukemia, synthesis, 3-aroyl-1,4-diarylpyrrole
ABSTRACT: We designed 3-aroyl-1,4-diarylpyrrole (ARDAP) derivatives as potential anticancer agents having different substitu-
ents at the 1- or 4-phenyl ring. ARDAP compounds exhibited potent inhibition of tubulin polymerization, binding of colchicine to
tubulin and cancer cell growth. ARDAP derivative 10 inhibited the proliferation of BCR/ABL-expressing KU812 and LAMA84 cells
from chronic myeloid leukemia (CML) patients in blast crisis and of hematopoietic cells ectopically expressing the imatinib mesylate
(IM)-sensitive KBM5-WT or its IM-resistant KBM5-T315I mutation. Compound 10 minimally affected the proliferation of normal
blood cells, indicating that it may be a promising agent to overcome broad tyrosine kinase inhibitor resistance in relapsed/refractory
CML patients. Compound 10 significantly decreased CML proliferation by inducing G2/M phase arrest and apoptosis via a mito-
chondria-dependent pathway. ARDAP 10 augmented the cytotoxic effects of IM in human CML cells. Compound 10 represents a
robust lead compound to develop tubulin inhibitors with potential as novel treatments for CML.
Chronic myeloid leukemia (CML) is a myeloproliferative
disease with an incidence of 1.8 new cases per 100,000 men and
women per year.1 The hallmark of CML is the reciprocal trans-
location t(9;22)(q34;q11) (i.e., the Philadelphia chromosome,
Ph) encoding for the hybrid protein BCR/ABL, a tyrosine ki-
nase with leukemogenic potential.2,3 At present, imatinib me-
sylate (IM, Gleevec), an inhibitor of both the BCR/ABL and c-
ABL tyrosine kinases, represents the treatment of choice for
CML, inducing stable clinical remissions in more than 80% of
newly-diagnosed patients.
However, point mutations in the catalytic domain of the
BCR/ABL oncoprotein4,5 or bcr/abl gene amplification6 can se-
lect IM-resistant clones in CML patients leading to a fatal blast
crisis phase. Among the reported BCR/ABL point mutations,
T315I (resulting in substitution of a threonine for an isoleucine
residue at the ‘gatekeeper’ position 315) is of particular interest
because it also provides resistance to clinically useful second-
generation tyrosine kinase inhibitors (TKIs) such as nilotinib,
dasatinib and bosutinib.7 Therefore, there is a pressing need for
devising novel combination regimens aimed at overcoming
TKI-resistance in CML cells.
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Microtubules are an attractive target for the development of
treatment of nitro derivatives 48-50 furnished ARDAPs 10 and
14 and compound 51, respectively. The latter compound was
converted to ARDAP 11 with sodium nitrite in tetrafluoroboric
acid. Reagents and reaction conditions are summarized in the
Scheme 1 legend.
effective anti-leukemia agents.8,9 Evidence has accumulated
correlating inhibition of tubulin polymerization and leukemic
cell proliferation.10-14 The activity of colchicine site agents in
CML has not been adequately explored. In continuing our stud-
ies on tubulin targeting agents, we designed new 3-aroyl-1,4-
diarylpyrrole (ARDAP) derivatives (Chart 1, Table 1).
In an initial screen, ARDAP 1 proved to be superior to 3 as
an inhibitor of MCF-7 cell growth (Table 1). Besides the ability
to inhibit tubulin polymerization, for which they were originally
designed, we found that ARDAP compounds augment IM-
mediated apoptotic effects in BCR/ABL+ CML cells obtained
from patients in blast crisis.
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ARDAP derivatives inhibited tubulin polymerization at mi-
cro- or submicromolar (4, 6, 7, 9 and 15) concentrations, as
compared with colchicine (IC50 = 3.2
μM) and combretastatin
A-4 (CSA4) (IC50 = 1.0 M). Most ARDAP compounds po-
μ
tently inhibited the growth of MCF-7 cells. ARDAPs 4, 7, 10,
15 and 16 exhibited IC50 values ≤30 nM.
Chart 1. ARDAP (1), ATI (2) and ARAP (3) derivatives.
Docking studies on ARDAP prototype 1 showed that the pro-
posed binding mode was significantly different from those of
its parent compounds ATI 215 and ARAP 3.16 However, the
three compounds all shared the key interactions of the tri-
methoxyphenyl moiety with the βCys241 of tubulin (Figure 1).
Observing the binding mode of ARDAP 1, we noticed that the
N-phenyl pyrrole group of 1 was placed in the same position as
the indole ring of 2, while the other ARDAP phenyl ring occu-
pied the same area as colchicine ring B.17 Based on these obser-
vations, we decided to investigate this new scaffold in search of
novel tubulin binding agents. We planned the synthesis of a
group of ARDAP derivatives bearing phenyl or substituted-
phenyl groups at positions 1 and 4 of the pyrrole nucleus (4-16,
Table 1). In this study, we introduced on the phenyl rings sub-
stituents that were associated with the best biological activity in
the ARAP series.16
Table 1. Inhibition of Tubulin Polymerization, Growth of
MCF-7 Human Breast Carcinoma Cells, and Colchicine
Binding by ARDAPs 4-16 and References 3, Colchicine and
CSA4.a
Tubulinb
IC50 ± SD
(μM)
1.1 ± 0.1
0.58 ± 0.02
1.6 ± 0.04
MCF-7c
IC50 ± SD
(nM)
Inh. Colch.
Bindingd
(% ± SD)
66 ± 1
compd
R1
H
R2
H
1
4
35 ± 7
30 ± 7
450 ± 70
57 ± 2
28 ± 3
280 ± 40
78 ± 4
9.0 ± 2
85 ± 7
120 ± 0
350 ± 90
74 ± 6
30 ± 0
15 ± 5
700 ± 200
5 ± 1
H
2-F
3-Me
3-F
72 ± 4
5
H
5.7 ± 5
53 ± 0.7
57 ± 0.7
24 ± 0.07
47 ± 4
6
H
0.63 ± 0.004
7
H
3-NH2 0.39 ± 0.05
8
H
4-Me
4-F
4-NH2
H
2.2 ± 0.1
0.76 ± 0.1
1.2 ± 0.1
2.0 ± 0.1
1.7 ± 0.09
2.9 ± 0.3
1.1 ± 0.08
0.88 ± 0.03
1.3 ± 0.1
1.5 ± 0.2
3.2 ± 0.4
1.0 ± 0.1f,g
9
H
10
11
12
13
14
15
16
3e
H
81 ± 2
2-F
3-Me
3-F
3-NH2
4-Me
4-F
—
29 ± 5
H
82 ± 2
H
42 ± 0.5
82 ± 4
H
H
79 ± 0.1
62 ± 2
H
—
80 ± 2
Colch
CSA4
—
—
—
—
—
13 ± 3
b
98 ± 0.6
Figure 1. Proposed binding modes for 1 (orange stick), 2 (green),
3 (cyan) and colchicine (gray) in the colchicine site.
aExperiments were performed in triplicate. Inhibition of tubulin
c
polymerization. Tubulin was at 10
μ
M in the assembly assay. In-
hibition of growth of MCF-7 human breast carcinoma cells. dInhi-
The new ARDAP derivatives were synthesized starting from
chalcones 25-31, which were converted to the corresponding
pyrrole derivatives 3216 or 33-39 with p-toluenesulfonylmethyl
isocyanide (TosMIC). ARDAP compounds 1, 4-6, 8, 9, 12, 13,
15, and 16 were obtained by reacting 3216 or 33-39 with the ap-
propriate boronic acid 40, 42, 43, 45 or 46. Reduction of 47 with
Pd/C-H2 (1 atm) gave the ARDAP derivative 7. Tin(II) chloride
bition of [3H]colchicine binding: tubulin, [3H]colchicine, inhibitor
e
at 1:5:5
μ
M. Lit.16 fCSA4 yielded an IC50 = 0.65 μM in an assay
contemporaneous with the evaluations of ARDAPs 5 and 7, in
which a different tubulin preparation was used. gCSA4 yielded an
IC50 of 0.79 μM in an assay contemporaneous with the evaluations
of 4, 6 and 9, in which a different tubulin preparation was used.
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Compound 10 was the most potent MCF-7 cell growth inhib-
The most potent ARDAP derivative 10 was investigated for
efficacy with BCR/ABL-expressing cells established in vitro
from CML patients in blast crisis (KU812 and LAMA 84) com-
pared with previously reported colchicine site binders 2-(1H-
imidazol-1-yl)-3-((3,4,5-trimethoxyphenyl)thio)-1H-indole19
(52) and (1-(3-aminophenyl)-1H-pyrrol-3-yl)(3,4,5-trimethox-
yphenyl)methanone16 (53). While derivatives 52 and 53 inhib-
ited CML cell growth (IC50) at concentrations ranging from 28
to 35 nM, ARDAP derivative 10 was the most potent compound
(IC50 = 12 and 14 nM, respectively) (Table 3S and Figure 3S,
Supporting Information). These results demonstrate that high
cytotoxicity can occur with compounds belonging to this new
class of compounds.
itor within the series with an IC50 of 9 nM. In general, inhibition
of colchicine binding correlated with inhibition of tubulin
polymerization and MCF-7 cell growth. The best tubulin as-
sembly inhibitor 7 (IC50 = 0.39 µM) inhibited the growth of
MCF-7 cells with an IC50 of 28 nM and colchicine binding by
57%. The best MCF-7 cell growth inhibitor 10 (IC50 = 9 nM)
inhibited tubulin polymerization with an IC50 of 1.2 μM and col-
10
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chicine binding by 81% (Table 1). As inhibitors of the ovarian
carcinoma cell lines OVCAR-8 and its cognate P-glycoprotein
(Pgp) overexpressing line NCI/ADR-RES, compound 7 yielded
IC50 values of 190 and 110 nM, and 16 of 180 and 110 nM,
respectively. With the exception of CSA-4, the reference col-
chicine, vinorelbine, vinblastine and paclitaxel were quite weak
inhibitors of the MDR cell line (Table 1S, Supporting Infor-
mation).
A dose-dependent inhibition of proliferation was observed
for KU812 and LAMA84 cells exposed to increasing doses of
10 for 48 h, as assessed by MTT assays. Compound 10 inhibited
CML cell growth by 50% at 12 nM. At such nanomolar concen-
trations, 10 minimally affected normal blood cells. Of note, pe-
ripheral blood mononuclear cells (PBMCs) isolated from
healthy donors remained substantially insensitive to 10 up to 1
Scheme 1. Synthesis of Compounds 1 and 4-16a
O
O
O
μM (Figure 2).
OMe
OMe
OMe
OMe
a
Me
H
R2
R2
+
OMe
OMe
OMe
OMe
OMe
25-31
17
18-24
R2
R3
O
R2
OMe
R1
O
OMe
OMe
N
(40-46)
b
c (R3 = B(OH)2)
d (R3 = I)
N
H
R1
32-39
1, 4-6, 8, 9, 12, 13, 15, 16, 47-50
R2
R2
OMe
OMe
OMe
OMe
O
O
g
e or f
OMe
51
)
(47-50)
(
OMe
N
N
Figure 2. Compound 10 decreased CML cell proliferation at
nanomolar concentrations without affecting normal PBMCs.
Experiments were performed in triplicate.
F
R1
10 14 51
7
11
,
,
,
ARDAPs 1 and 4-16: see Table 1. 18, 25: R2 = 2-F; 19, 26: R2 = 3-Me; 20, 27: R2 = 3-F;
21, 28: R2 = 3-NO2; 22, 29: R2 = 4-Me; 23, 30: R2 = 4-F; 24, 31: R2 = 4-NO2; 32: R2 = H;
33: R2 = 2-F; 34: R2 = 3-Me; 35: R2 = 3-F; 36: R2 = 3-NO2; 37: R2 = 4-Me; 38: R2 = 4-F;
Based on the above data, by virtue of its anti-leukemic poten-
tial, we extended the analysis of biological effects of 10 to pro-
liferation and viability of IM-sensitive KBM5 and IM-resistant
KBM5-T315I cells (Figure 3). By performing MTT assays, we
found that 10 dose-dependently blocked growth of KBM5 and
KBM5-T315I cells with similar average IC50 values of 15 and
18 nM, respectively. The anti-leukemic activity of 10 in
BCR/ABL+ cells expressing the T315I gatekeeper mutation in-
dicated that the drug may be a promising agent to overcome
broad TKI-resistance in relapsed/refractory CML patients.
39: R2 = 4-NO2; 40: R1 = H, R3 = B(OH)2; 41: R1 = 2-NO2, R3 = I; 42: R1 = 3-Me, R3
=
B(OH)2; 43: R1 = 3-F, R3 = B(OH)2; 44: R1 = 3-NO2, R3 = I; 45: R1 = 4-Me, R3 = B(OH)2;
46: R1 = 4-F, R3 = B(OH)2; 47: R1 = H, R2 = 3-NO2; 48: R1 = H, R2 = 4-NO2; 49: R1 = 2-
NO2, R2 = H; 50: R1 = 3-NO2, R2 = H; 51: R1 = 2-NH2, R2 = H.
aReagents and reaction conditions. (a) NaOH, EtOH, 25 °C, 24
h, 59-89%; (b) TosMIC, NaH, DMSO/Et2O, 25 °C, 4 h, Ar, 21-
84%; (c) (1, 4, 5, 8, 9, 12, 13, 15, 16, 47 and 48) boronic acid 40,
42, 43, 45 or 46, Cu(AcO)2, Et3N, DCE, reflux, Ar, 4-72%; (d) (49
and 50) 41 or 44, CuBr, Cs2CO3, quinoline N-oxide, DMSO, 65 °C,
6 h, Ar, 9 and 34%; (e) (7) H2, Pd/C, MeOH, 1 atm, 25 °C, 2 h,
82%; (f) (10, 14 and 51) SnCl2.2H2O, MeCOOEt, reflux, 6 h, 47-
60%; (g) NaNO2, HBF4, 0 °C, 1 h, 13%.
Compounds 7, 10 and 16 were evaluated for growth inhibi-
tion of the KYSE150 (esophageal squamous cell), THP-1 (acute
monocytic leukemia), NB4 (acute promyelocytic leukemia),
HT-29 (human colorectal adenocarcinoma), HCT116 (colon
cancer) and HepG2 (liver hepatocellular) cell lines (Table 2S,
Supporting Information). Derivative 10 was found to be the
most potent compound, with IC50 values ranging from 20 nM
(KYSE150 and HCT116) to 46 nM (HepG2).
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Figure 3. Cytotoxicity of 10 on CML cells ectopically ex-
of IM, when annexin V-FITC staining was used to detect early
cell death at 24 h (Figure 5B).
pressing the IM-sensitive wild type KBM5-WT or its IM-
resistant KBM5-T315I mutation. Experiments were performed
in triplicate.
Given that 10 interferes with tubulin function, we then exam-
ined cell morphological features under phase contrast micros-
copy and cell cycle distribution by flow cytometry (Figure 1S,
Supporting Information). Compared to cell cultures incubated
with DMSO as vehicle control (ctrl), KU812 cells treated with
100 nM 10 showed an elongated shape and multiple centro-
somes typical of giant cells with failed cytokinesis and altered
tubulin immunostaining (Figure 1S, Panel A).
A rapid collapse of mitochondrial transmembrane potential
was detected in KU812 cells exposed to 100 nM 10 for 8 h, to
a greater extent as compared with those exposed to IM (100 nM
for 8 h), as a consequence of the opening of permeability tran-
sition pores that accumulate a fluorescent dye from its red-ag-
gregated to its green-monomeric forms (Figure 4A, left panels).
Specifically, a majority (97.8%) of solvent-treated KU812 cells
had a bright red fluorescence, indicative of intact mitochondria,
while 35.3% of 10-treated KU812 cells at 100 nM for 8 h ex-
hibited a marked green fluorescence indicative of damaged mi-
tochondria. Nuclear morphology of 10-treated KU812 cells was
also evaluated using Hoechst-3258 staining (Figure 4B, right
panels); a blue-to-cyan fluorescence was detected in most of the
nuclei of 10-treated vs DMSO-control cells indicating their
apoptotic morphology. Taken together, these data indicated that
10 significantly decreased CML proliferation by inducing
G2/M phase arrest and apoptosis via a mitochondria-dependent
pathway.
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These characteristics, typically resembling those referred to
as mitotic catastrophe, occurred at relatively early (2 to 8 h) ex-
posure intervals correlating with a net mitotic arrest of 10-
treated cells accumulated in the G2/M cell cycle phase (60.3 ±
3.4% of treated vs 35.7 ± 2.8% of control cells), whereas apop-
totic cells in the subG1 phase did not exceed 10%. After a 24 h
treatment, cell mitotic abnormalities disappeared in keeping
with a reduced G2/M fraction reaching 11.4 ± 8.3%, whilst a
massive apoptosis induction (peaking at 75.6 ± 11.4% of 10-
treated cells vs 0.4 ± 0.8% of control cells) indicated a greater
susceptibility to death following the initial mitotic arrest (Figure
1S, Panel B).
Figure 4. Compound 10 promotes CML cell death via mito-
chondrial-dependent pathways – comparsion with IM. Experi-
ments were performed in triplicate.
We examined the ability of 10 to augment the cytotoxic ef-
fects of IM in human CML cells. To study this, LAMA84 cells
were incubated for 48 h with increasing doses of IM (range 1-
1000 nM) in the absence or presence of 100 nM 10 and then
analyzed by the MTT assay (Figure 5A). The combined regi-
men of IM and 10 was more effective than IM alone in reducing
CML cell growth, lowering the IC50 value for IM from 100 nM
to less than 10 nM. It had been reported previously that the av-
erage IC50 value for IM in LAMA84 cells overexpressing BCR-
ABL is 100 nM,4 and this was also observed here. Similar re-
sults were also obtained using KU812 cells (data not shown). In
addition, the IM-resistant KBM5-T315I cells showed the same
susceptibility to 10-induced cell death as well as IM-sensitive
KBM5-WT cells, reaching respectively 58.2 ± 4.5% and 62.6 ±
5.4% of annexin V+ cells at 48 h of drug exposure as compared
to 2.2 ± 1.8% for control cells. Most importantly, exposure to
100 nM 10 significantly augmented the pro-apoptogenic effects
Figure 5. Compound 10 potentiates IM-mediated cell death
of CML cells, including those expressing the T315I mutation.
Experiments were performed in triplicate.
It is worth noting that IM, when used as a single agent at 100
nM, was ineffective in altering CML KU812 cell shape or via-
bility, causing only a weak anti-proliferative effect at 24 h (56.3
± 3.4% in IM-treated vs 42.7 ± 6.2% in DMSO-treated cells ar-
rested in the G1 phase of the cell cycle). As shown in Figure 1S,
Panel C, the levels of the growth inhibitory protein p21Cip/WAF1
were rapidly up-regulated after 6 h of 10 treatment and de-
creased after 24 h when the cleavage of the pro-apoptotic pro-
tein PARP indicated prominent activation. In keeping with this
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observation, treatment with 10 also increased caspase-3 activa-
tion in a time-dependent fashion, as assessed by flow cytometry
(Figure 1S, Panel D).
Funding Sources
This research was supported by grants PRIN 2015 n.
2015FCHJ8E (R.S.), AIRC-IG n. IG.14236 (A.M.L.C.), Ricerche
Universitarie 2015 Sapienza Università di Roma n. C26A15J3BB
(G.L.R.) and n. C26A15RT82 (A.C.) and Finanziamenti Ateneo
2016 Sapienza Università di Roma (G.L.R.).
To determine whether 10 interferes with BCR/ABL phospho-
activation and its signal transduction machinery, LAMA84 cells
were cultured for 24 h in the presence of IM or 10, both at 100
nM. Cells were then lysed and analyzed by Western immunob-
lotting (Figure 2S, Supporting Information). Treatment with 10
did not alter auto-activation, while total levels of E-cadherin
were substantially reduced compared to cells incubated with
DMSO or IM. Compound 10 also reduced the active pools of
unphosphorylated β-catenin and phospho-cofilin without af-
fecting their total protein levels. Since β-catenin and cofilin act
as cytoskeletal adaptor proteins and are critical determinants of
CML cell growth, it seems conceivable that these two mole-
cules may elicit the anti-leukemic potential of 10, beyond its
expected effects on tubulin function.
Notes
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The authors declare no competing financial interest.
Disclaimer
The content of this paper is solely the responsibility of the authors
and does not necessarily reflect the official views of the National
Institutes of Health.
ABBREVIATIONS
ARDAP, 3-aroyl-1,4-diarylpyrrole; CML, chronic myeloid leu-
kemia; BCR, breakpoint cluster region; ABL, abelson gene;
BCR/ABL fusion gene; ATI, arylthioindole; ARAP, 3-aroyl-1-ar-
ylpyrrole; CSA4, combretastatin A-4; TosMIC, p-toluenesulfonyl-
methyl isocyanide; DCE, 1,2-dichloroethane; PBMC, peripheral
blood mononuclear cell; IM, imatinib mesylate.
In conclusion, we synthesized ARDAP derivatives as poten-
tial anticancer agents. The new ARDAPs inhibited tubulin
polymerization with IC50 values in the micro- or submicromolar
concentration range. Most compounds inhibited the prolifera-
tion of human MCF-7 cells with IC50 values ≤30 nM. The most
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ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the ACS
Publications website.
Additional biological information, experimental procedures for
the synthesis and characterization of 4-16, molecular modeling
and biological assays (pdf file).
AUTHOR INFORMATION
Corresponding Author
*Phone: +39 06 4991 3800. Fax: +39 06 4991 3133. E-mail:
romano.silvestri@uniroma1.it.
Author Contributions
G.L.R, V.F., S.P. and M.N.: chemical synthesis; A.C. and A.B.:
molecular modeling studies; R.B. and E.H.: tubulin studies and
MCF-7, OVCAR-8 and NCI/ADR-RES cell growth inhibition;
C.S. and A.M.L.C: biological screenings.
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