Design, synthesis and biological evaluation of novel arylpiperazine derivatives on human prostate cancer cell lines

Article abstract of DOI:10.1016/j.bmcl.2014.11.049

A series of novel arylpiperazine derivatives was synthesized. The in vitro cytotoxic activities of all synthesized compounds against three human prostate cancer cell lines (PC-3, LNCaP, and DU145) were evaluated by a CCK-8 assay. Compounds 10, 24 and 29 e

Full text of DOI:10.1016/j.bmcl.2014.11.049

Bioorganic & Medicinal Chemistry Letters xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Design, synthesis and biological evaluation of novel arylpiperazine
derivatives on human prostate cancer cell lines
⇑
Hong Chen , Fang Xu , Xue Liang, Bing-Bing Xu, Zong-Lin Yang, Xue-Lan He, Bi-Yun Huang, Mu Yuan
Pharmaceutical Research Center, Guangzhou Medical University, Guangzhou 510182, China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel arylpiperazine derivatives was synthesized. The in vitro cytotoxic activities of all synthe-
sized compounds against three human prostate cancer cell lines (PC-3, LNCaP, and DU145) were evalu-
ated by a CCK-8 assay. Compounds 10, 24 and 29 exhibited strong cytotoxic activities against LNCaP cells
(IC50 <3 lM). In addition, these compounds exhibited weak cytotoxic effects on human epithelial prostate
normal cells RWPE-1. The structure–activity relationship (SAR) of these arylpiperazine derivatives was
Received 15 August 2014
Revised 12 November 2014
Accepted 18 November 2014
Available online xxxx
also discussed based on the obtained experimental data.
Keywords:
Ó 2014 Published by Elsevier Ltd.
Synthesis
Arylpiperazine derivatives
Cytotoxic activity
CCK-8
Structure–activity relationship
Amongst various human diseases, mortality and morbidity of
cancer patients is the second highest in the world today, following
heart disease.1–3 Despite recent advances in the understanding of
the biological processes leading to the development of cancer, it
remains with a strong need to develop more potent and selective
agents. The selective targeting of tumor cells is the goal of modern
cancer chemotherapy aimed at overcoming the nonspecific toxicity
of most anticancer agents against normal cells.4 At present, much
of successful cancer chemotherapy probably lies in utilizing
differences in cell kinetics between tumor and normal tissue,
because most drugs can show some selective toxicity toward
rapidly-dividing cells compared to noncycling cells.5 So, drugs
designed are expected to have high affinity with the novel targets,
and they not only inhibit the proliferation but also differentiation
of tumor cells and speed up their death.6 Due to drawbacks of con-
ventional cancer chemotherapy, such as dose limits, side effects,
drug-resistant and low selectivity to cancer cells, discovery and
development of much more effective, safe and highly selective
antitumor drugs is still a major challenge for the researchers.7
Compounds with arylpiperazine moieties have a wide range of
bioactivities including antiarrhythmic,8 diuretic,9 antiallergic,10
antidepressant,11 anxiolytic,12 antipsychotic,13 antimalarial,14 anti-
plasmodial15 and anti-proliferative16–18 properties. In addition,
these compounds also display receptor-blocking properties.9,19–23
Naftopidil, an arylpiperazine compound, is a specific
a1d-adrener-
gic receptor antagonist,24,25 and it is one of the most widely used
a
1-adrenergic receptor antagonists in Japan for the treatment of
benign prostatic hyperplasia (BPH).26,27 Recent studies have shown
that naftopidil could possibly exert an anticancer effect and inhibit
prostate cancer cell growth by arresting the G1 cell cycle
phase,28,29 as well as induce apoptosis in malignant mesothelioma
cell lines.30 Many studies have shown that arylpiperazine deriva-
tives may act as potential
a1a- and/or a1a- + a1d-selective ligands
for the treatment of BPH. However, there have been few studies
on anti-cancer activities of these compounds against human pros-
tate cancer cells.31–36 In our previous works,37 we reported anti-
prostate cancer activities of a series of arylpiperazine derivatives
bearing 1,3-benzodioxol moiety. In this work, we report the
synthesis of a series of novel arylpiperazinyl derivatives bearing
3,5-dimethoxyphenoxyl moiety (Scheme 1) with the intention of
identifying much more effective anti-prostate cancer drugs. All
synthesized compounds were evaluated for their cytotoxic activi-
ties against three human prostate cancer cell lines PC-3, LNCaP
and DU145 cell line, and human prostate epithelial cell line
RWPE-1. The SAR was further discussed on the basis of the
obtained experimental data. As we expected, some compounds
exhibited strong anti-cancer activities against the tested cancer
cells and superior potency than naftopidil.
As depicted in Scheme 1, a series of novel arylpiperazine deriv-
atives were synthesized starting from the commercially available
2-(4-(bromomethyl)phenyl)acetic acid 1. First, compound 1 was
reduced to alcohol 2 in the presence of a borane–methyl sulfide
⇑
Corresponding author. Tel./fax: +86 020 8134 0727.
E-mail address: mryuanmu838@sina.com (M. Yuan).
These authors contributed equally to this work.
http://dx.doi.org/10.1016/j.bmcl.2014.11.049
0960-894X/Ó 2014 Published by Elsevier Ltd.
Please cite this article in press as: Chen, H.; et al. Bioorg. Med. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.bmcl.2014.11.049

2
H. Chen et al. / Bioorg. Med. Chem. Lett. xxx (2014) xxx–xxx
O
OH
OH
O
O
(i)
(ii)
OH
Br
Br
O
3
2
1
O
O
O
O
(iv), (v)
.x HCl
N Ar
OTs
N
(iii)
4
5-29
O
O
N
8, Ar =
9, Ar =
7, Ar =
5, Ar =
6, Ar =
O
O
13, Ar =
14, Ar =
O
F
12, Ar =
10, Ar =
11, Ar =
F
O
O
F
F
18, Ar =
23, Ar =
28, R =
19, Ar =
24, Ar =
17, Ar =
22, Ar =
27, Ar =
15, Ar =
20, Ar =
25, Ar =
16, Ar =
21, Ar =
26, Ar =
Cl
Cl
Cl
Cl
Cl
Cl
Cl
F3C
CN
29, R =
CF3
Br
O
S
O
Scheme 1. Reagents and conditions: (i) BH3ÁS(CH3)2, THF, 0 °C for 1 h, and then room temperature for 10 h; (ii) 3,5-dimethoxyphenol, K2CO3, CH3CN, reflux, 16 h; (iii) TsCl,
Et3N and 4-dimethylaminopyridine, Cl2CH2, 0 °C, 16 h; (iv) arylpiperazines, K2CO3, CH3CN, reflux, 16 h; (v) HCl, AcOEt, rt, 0.5 h.
Table 1
complex (2 M in tetrahydrofuran) at 0 °C for 1 h, and then at room
temperature for 10 h. The intermediate 2 was directly used with-
In vitro cytotoxicity of compounds 5–29
M)a
out further purification. The nucleophilic substitution reaction of
Compd
IC50
(
l
compound 2 with 3,5-dimethoxyphenol in the presence of potas-
PC-3b
LNCaPb
>50
DU145b
RWPE-1b
sium carbonate (K2CO3) gave compound
3 (70% yield from
5
6
7
8
9
31.20 1.40
25.58 0.40
6.79 0.08
25.04 3.30
16.78 1.05
5.83 0.75
>50
>50
>50
35.61 2.36
>50
>50
>50
28.79 0.95
>50
>50
39.88 1.52
>50
35.42 1.56
>50
>50
>50
>50
>50
36.60 1.63
36.45 1.78
>50
compound 1) after 16 h at reflux. Compound 3 was treated with
4-toluene-sulfonyl chloride in the presence of triethylamine and
a catalytic amount of 4-dimethylaminopyridine at 0 °C for 16 h
to generate compound 4 (95% yield). Finally, the reactions of com-
pound 4 with various arylpiperazines in the presence of K2CO3 at
reflux for 16 h gave arylpiperazine derivatives 5–29 (55–75% yield;
Scheme 1). The structures of the compounds (as their HCl salts)
were confirmed using 1H NMR, 13C NMR, MS (ESI) and elemental
analyses (C, H, and N).
The synthesized target compounds 5–29 were evaluated for
their in vitro cytotoxic activities against the three human prostate
cancer cell lines (PC-3, LNCaP, and DU145), and compared with
their effects on human prostate epithelial cell line RWPE-1 by
CCK-8 assay.37–40 The results are summarized in Table 1.
42.27 2.17
6.07 0.08
35.76 5.26
35.21 3.24
2.35 0.33
36.12 4.23
26.29 0.74
>50
30.25 0.16
48.17 1.44
30.64 0.77
30.98 1.54
26.54 3.22
27.14 0.86
32.92 0.18
25.27 0.52
27.05 0.85
25.31 2.21
28.75 0.28
35.42 0.78
25.16 2.35
18.92 1.02
30.91 1.00
18.45 0.35
32.18 2.53
25.56 0.60
40.26 2.56
23.79 0.59
27.63 0.04
9.42 0.54
19.26 0.78
24.13 2.68
28.62 2.12
27.60 2.52
30.52 4.17
27.17 0.84
19.16 0.24
16.92 0.36
26.65 0.39
25.36 0.79
28.20 0.39
24.16 0.89
23.18 0.59
12.67 1.02
27.09 0.18
30.17 3.00
27.96 0.29
29.47 1.32
39.25 1.35
28.48 3.25
46.34 1.14
7.68 1.02
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Naftopidil
>50
20.04 1.05
39.81 7.07
7.25 0.62
35.04 2.23
>50
32.47 2.02
>50
36.57 1.88
>50
2.73 0.75
>50
>50
>50
>50
As shown in Table 1, some compounds exhibited moderate to
strong cytotoxic activities against the tested cancer cell lines, and
even exhibited much better activity than naftopidil. For example,
the compounds 7, 10, 17, 24 and 29 exhibited strong cytotoxic
>50
>50
45.84 2.31
>50
>50
activities against LNCaP cells (IC50 <10 lM). In addition, com-
pounds 7, 10 and 29 exhibited weak cytotoxic effects on normal
RWPE-1 human epithelial prostate cells. Moreover, compounds 7
and 29 showed the potent activity against tested cancer cells (Sup-
plementary data in Fig. S1).
0.97 0.04
22.36 0.61
42.10 0.79
34.58 0.31
a
IC50 values are taken as means standard deviation from three experiments.
PC-3, LNCaP and DU145, human prostate cancer cell line; RWPE-1, the human
b
The SAR analysis revealed the following: (1) Compared to
prostate epithelial cell line.
phenylpiperazine derivative 5, benzylpiperazine derivative
7
(IC50 = 6.79, 6.07 and 5.83 M, respectively) exhibited potent cyto-
l
compounds 7 exhibited weak cytotoxic effects on human epithelial
prostate normal cells RWPE-1. (2) Compound 10 exhibited strong
cytotoxic activities (IC50 = 2.35 lM) against LNCaP cells compared
toxic activities against PC-3, LNCaP and DU145 cells. These results
suggest that the introduction of a benzyl moiety at the 4-position
of piperazine ring was beneficial for anti-cancer activity. Moreover,
Please cite this article in press as: Chen, H.; et al. Bioorg. Med. Chem. Lett. (2014), http://dx.doi.org/10.1016/j.bmcl.2014.11.049

H. Chen et al. / Bioorg. Med. Chem. Lett. xxx (2014) xxx–xxx
3
3. David, V.; Jaime, R. A.; Cristina, T.; Pedro, C. B.; Jaime, V. A. Eur. J. Med. Chem.
2010, 45, 5234.
4. Falciani, C.; Brunetti, J.; Pagliuca, C.; Menichetti, S.; Vitellozzi, L.; Lelli, B.; Pini,
A.; Bracci, L. ChemMedChem 2010, 5, 567.
with compounds 8 and 9. The activity profiles indicated that a
methyl group at the m-position on the phenyl group was beneficial
for anti-cancer activity (3) Compound 14 lost potency (IC50
5. Tannock, I. F. Cancer Treat. Rep. 1978, 62, 1117.
6. Vinaya, K.; Kavitha, C. V.; Chandrappa, S.; Prasanna, D. S.; Raghavan, S. C.;
Rangappa, K. S. Chem. Biol. Drug Des. 2011, 78, 622.
7. Eckhardt, S. Curr. Med. Chem. Anticancer Agents 2002, 2, 419.
8. Szkaradek, N.; Rapacz, A.; Pytka, K.; Filipek, B.; Siwek, A.; Cegła, M.; Marona, H.
Bioorg. Med. Chem. 2013, 21, 514.
9. Cecchetti, V.; Fravolini, A.; Schiaffella, F.; Tabarrini, O.; Bruni, G.; Segret, G. J.
Med. Chem. 1993, 36, 157.
>50
l
M) against LNCaP cells compared with compounds 12 and
M, respectively). These results suggest
15 (IC50 = 26.29 and 20.04
l
that a methoxyl group at the p-position on the phenyl group was
inauspicious for anti-cancer activity. A similar potency profile
was observed in compounds 20, 21, and 22. (4) Compound 17
(IC50 = 7.25 lM) exhibited a more effective cytotoxic activity than
compounds 18 and 19 against LNCaP cells. Activity profiles indi-
cated that a fluoro group at the o-position on the phenyl group
was beneficial for anti-cancer activity. Moreover, compound 17
showed excellent selective activity for LNCaP cells over the other
tested cancer cells. (5) Compounds with a methyl group at the o-
position and a chloro group at the m-position on the phenyl group
displayed better activity for LNCaP cells than did the o-methyl-
substituted or m-chloro-substituted group for LNCaP cells, as
10. Walsh, D. A.; Chen, Y. H.; Green, J. B.; Nolan, J. C.; Yannit, J. M. J. Med. Chem.
1823, 1990, 33.
11. Seo, H. J.; Park, E. J.; Kim, M. J.; Kang, S. Y.; Lee, S. H.; Kim, H. J.; Lee, K. N.; Jung,
M. E.; Lee, M.; Kim, M. S.; Son, E. J.; Park, W. K.; Kim, J.; Lee, J. J. Med. Chem.
2011, 54, 6305.
12. Kikumoto, R.; Tobe, A.; Fukami, H.; Egawa, M. J. Med. Chem. 1983, 26, 246.
13. Jaen, J. C.; Wise, L. D.; Heffner, T. G.; Pugsley, T. A.; Meltzed, L. T. J. Med. Chem.
1988, 31, 1621.
14. Cross, R. M.; Namelikonda, N. K.; Mutka, T. S.; Luong, L.; Kyle, D. E.; Manetsch,
R. J. Med. Chem. 2011, 54, 8321.
15. Clarkson, C.; Musonda, C. C.; Chibale, K.; Campbella, W. E.; Smitha, P. Bioorg.
Med. Chem. 2003, 11, 4417.
16. Berardi, F.; Abate, C.; Ferorelli, S.; De Robertis, A. F.; Leopoldo, M.; Colabufo, N.
A.; Niso, M.; Perrone, R. J. Med. Chem. 2008, 51, 7523.
17. Abate, C.; Niso, M.; Contino, M.; Colabufo, N. A.; Ferorelli, S.; Perrone, R.;
Berardi, F. ChemMedChem 2011, 6, 73.
18. Liu, W. H.; Chang, J. X.; Liu, Y.; Luo, J. W.; Zhang, J. W. Acta Pharm. Sin. 2013, 48,
1259.
exemplified by compound 24 (IC50 = 2.73 lM) with significantly
improved activity, while compounds 8 and 22 exhibited moderate
cytotoxic activity. (6) In addition, compound 29 with a methylsul-
phonyl group at the o-position on the phenyl group displayed
potent cytotoxic activity against LNCaP cells (IC50 = 0.97 lM), and
excellent selective activity for LNCaP cells over the other tested
cancer cells. Moreover, compounds 29 exhibited weak cytotoxic
effects on human epithelial prostate normal cells RWPE-1.
In summary, this study reported the synthesis and biological
evaluation against three human prostate cancer cells and human
prostate epithelial cells of a novel class of arylpiperazine deriva-
tives. Some compounds exhibited strong cytotoxic activities against
tested cancer cell lines. The compounds with a methylsulphonyl
(29) group at the o-position on the phenyl group demonstrated a
relatively strong cytotoxicity against LNCaP cells. These positive
results could serve as a valuable guideline for further research on
arylpiperazine derivatives as novel anti-prostate cancer agents. Fur-
ther research involving other class of arylpiperazine derivatives,
and preparation of analogs with other aryl groups instead of a
3,5-dimethoxyphenoxyl group are in progress.
19. Leopoldo, M.; Lacivita, E.; Passafiume, E.; Contino, M.; Colabufo, N. A.; Berardi,
F.; Perrone, R. J. Med. Chem. 2007, 50, 5043.
20. Chen, X.; Sassano, M. F.; Zheng, L. Y.; Setola, V.; Chen, M.; Bai, X.; Frye, S. V.;
Wetsel, W. C.; Roth, B. L.; Jin, J. J. Med. Chem. 2012, 55, 7141.
21. Romeiro, L. A.; Da Silva Ferreira, M.; Da Silva, L. L.; Castro, H. C.; Miranda, A. L.;
Silva, C. L.; Noël, F.; Nascimento, J. B.; Araújo, C. V.; Tibiriçá, E.; Barreiro, E. J.;
Fraga, C. A. Eur. J. Med. Chem. 2011, 46, 3000.
22. Baran, M.; Kepczynska, E.; Zylewski, M.; Siwek, A.; Bednarski, M.; Cegla, M. T.
Med. Chem. 2014, 10, 144.
23. Ananthan, S.; Saini, S. K.; Zhou, G.; Hobrath, J. V.; Padmalayam, I.; Zhai, L.;
Bostwick, J. R.; Antonio, T.; Reith, M. E.; McDowell, S.; Cho, E.; McAleer, L.;
Taylor, M.; Luedtke, R. R. J. Med. Chem. 2014, 57, 7042.
24. Dellabella, M.; Milanese, G.; Muzzonigro, G. J. Urol. 2003, 170, 2202.
25. Morita, T.; Wada, I.; Saeki, H.; Tsuchida, S.; Weiss, R. M. J. Urol. 1987, 137, 132.
26. Nishino, Y.; Masue, T.; Miwa, K.; Takahashi, Y.; Ishihara, S.; Deguchi, T. BJU Int.
2006, 97, 747.
27. Kojima, Y.; Sasaki, S.; Kubota, Y.; Hayase, M.; Hayashi, Y.; Shinoura, H.;
Tsujimoto, G.; Kohri, K. J. Urol. 2008, 179, 1040.
28. Hori, Y.; Ishii, K.; Kanda, H.; Iwamoto, Y.; Nishikawa, K.; Soga, N.; Kise, H.;
Arima, K.; Sugimura, Y. Cancer Prev. Res. (Phila.) 2011, 4, 87.
29. Kanda, H.; Ishii, K.; Ogura, Y.; Imamura, T.; Kanai, M.; Arima, K.; Sugimura, Y.
Int. J. Cancer 2008, 122, 444.
Acknowledgments
30. Masachika, E.; Kanno, T.; Nakano, T.; Gotoh, A.; Nishizaki, T. Anticancer Res.
2013, 33, 887.
31. Li, S.; Chiu, G.; Pulito, V. L.; Liu, J.; Connolly, P. J.; Middleton, S. A. Bioorg. Med.
Chem. Lett. 2007, 17, 1646.
32. Chiu, G.; Li, S.; Connolly, P. J.; Pulito, V.; Liu, J.; Middleton, S. A. Bioorg. Med.
Chem. Lett. 2007, 17, 3292.
33. Kuo, G. H.; Prouty, C.; Murray, W. V.; Pulito, V.; Jolliffe, L.; Cheung, P.; Varga, S.;
Evangelisto, M.; Shaw, C. Bioorg. Med. Chem. 2000, 8, 2263.
34. Khatuya, H.; Hutchings, R. H.; Kuo, G. H.; Pulito, V. L.; Jolliffe, L. K.; Li, X.;
Murray, W. V. Bioorg. Med. Chem. Lett. 2002, 12, 2443.
The project was supported by the Technological Innovation Pro-
ject of Colleges and Universities in Guangdong Province (No.
cx2d1127), the China Postdoctoral Science Foundation (Nos.
2013M542165 and 2013M531837), the National Science Founda-
tion of Guangdong Province (No. S2013040014088) and the
Guangzhou Postdoctoral Scientific Research Foundation (Nos.
Q130 and Q074).
35. Konkel, M. J.; Wetzel, J. M.; Cahir, M.; Craig, D. A.; Noble, S. A.; Gluchowski, C. J.
Med. Chem. 2005, 48, 3076.
36. Romeo, G.; Materia, L.; Modica, M. N.; Pittalà, V.; Salerno, L.; Siracusa, M. A.;
Manetti, F.; Botta, M.; Minneman, K. P. Eur. J. Med. Chem. 2011, 46, 2676.
37. Chen, H.; Liang, X.; Xu, F.; Xu, B. B.; He, X. L.; Huang, B. Y.; Yuan, M. Molecules
2014, 19, 12048.
38. Kaspers, G. J.; Veerman, A. J.; Pieters, R.; Van Zantwijk, C. H.; Smets, L. A.; Van
Wering, E. R.; Van Der Does-Van Den Berg, A. Blood 1997, 90, 2723.
39. Kaspers, G. J.; Pieters, R.; Van Zantwijk, C. H.; Van Wering, E. R.; Van Der Does-
Van Den Berg, A.; Veerman, A. J. Blood 1998, 92, 259.
40. Ding, J.; Huang, S. L.; Wu, S. Q.; Zhao, Y. J.; Liang, L. H.; Yan, M. X.; Ge, C.; Yao, J.;
Chen, T. Y.; Wan, D. F.; Wang, H. Y.; Gu, J. R.; Yao, M.; Li, J. J.; Tu, H. Nat. Cell Biol.
2010, 12, 390.
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2014.11.
049.
References and notes
1. Heron, M. Natl. Vital Stat. Rep. 2009, 58, 1.
2. Heron, M. Natl. Vital Stat. Rep. 2007, 56, 1.
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