Synthesis and biological evaluation of a new series of histone deacetylases inhibitors
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Synthesis and biological evaluation of a new series of histone deacetylases inhibitors Jie Jiao, Qiang Wang, Hua Wei Zhu, Hao Fang, Wen Fang Xu * School of Pharmaceutical Science, Shandong University, Jinan 250012, China Received 7 January 2008 Abstract Histone deacetylases (HDACs) play an important role in tumorigenesis. Inhibition of HDACs is considered as a potent strategy for cancer therapy. Two lead compounds (ja and jb) were found to have activities against HDACs with IC 50 at about 15 mmol/L. Then a new series of hydroximic acid derivatives were designed and synthesized based on them. The HDACs activity assay in vitro found that compounds J04 and J09 are nearly as potent as the positive control drug Zolinza. # 2008 Wen Fang Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: HDACs; Tumorigenesis; Cancer therapy; Hydroximic acid Histone deacetylases (HDACs) belong to a family of zinc dependent hydrolase which regulate and control the acetylated degree of histones [1]. In cancer cells, they are over-expressed resulting in excessive acetylated histones which pack DNA tightly to produce an abnormal structure of chromatin. In this process, expressions of onco- suppressors (p53/p21WAF1/p27KIP1) are repressed, whereas tumor activators (HIF-1/VEGF) are up-regulated. Therefore the inhibition of HDACs activity has been recognized as a potent strategy for cancer therapy [2,3]. Among the HDACs inhibitors, small-molecular hydroximic acids are the most class [4]. A common pharmacophore of these inhibitors shows there are three basic elements in their structures: a zinc bind group (ZBG) to chelate the zinc ion in the catalytic site of the enzyme and a hydrophobic group are linked by a short fatty chain or an aromatic group [4]. One of them, SAHA (trade name Zolinza), has been approved by FDA for cutaneous T-cell lymphoma patients in 2006 [5]. In our lab, two new compounds (ja and jb) were found to show activities against HDACs (Fig. 1) and their IC 50 value is about 15 mmol/L. They were both synthesized from ferulic acid, a natural botanical product isolated from herb Rhizoma Chuanxiong. Subsequently a new series of compounds were designed and synthesized based on ja and jb. The hydrophobic groups of them are linked by five common amino acids (glycin, b-alanine, g-aminobutyric acid, para-aminobenzoic acid and meta-aminobenzoic acid) because they contain a short fatty chain or an aromatic group and their carboxyl group can be converted to be hydroximic acid group (ZBG) (Fig. 1). The synthetic route has been shown in Scheme 1. www.elsevier.com/locate/cclet Available online at www.sciencedirect.com Chinese Chemical Letters 19 (2008) 673–675 * Corresponding author. E-mail address: [email protected] (W.F. Xu). 1001-8417/$ – see front matter # 2008 Wen Fang Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2008.04.010
Transcript of Synthesis and biological evaluation of a new series of histone deacetylases inhibitors
Synthesis and biological evaluation of a new series of histone
deacetylases inhibitors
Jie Jiao, Qiang Wang, Hua Wei Zhu, Hao Fang, Wen Fang Xu *
School of Pharmaceutical Science, Shandong University, Jinan 250012, China
Received 7 January 2008
Abstract
Histone deacetylases (HDACs) play an important role in tumorigenesis. Inhibition of HDACs is considered as a potent strategy
for cancer therapy. Two lead compounds (ja and jb) were found to have activities against HDACs with IC50 at about 15 mmol/L.
Then a new series of hydroximic acid derivatives were designed and synthesized based on them. The HDACs activity assay in vitro
found that compounds J04 and J09 are nearly as potent as the positive control drug Zolinza.
# 2008 Wen Fang Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords: HDACs; Tumorigenesis; Cancer therapy; Hydroximic acid
Histone deacetylases (HDACs) belong to a family of zinc dependent hydrolase which regulate and control the
acetylated degree of histones [1]. In cancer cells, they are over-expressed resulting in excessive acetylated histones
which pack DNA tightly to produce an abnormal structure of chromatin. In this process, expressions of onco-
suppressors (p53/p21WAF1/p27KIP1) are repressed, whereas tumor activators (HIF-1/VEGF) are up-regulated.
Therefore the inhibition of HDACs activity has been recognized as a potent strategy for cancer therapy [2,3]. Among
the HDACs inhibitors, small-molecular hydroximic acids are the most class [4]. A common pharmacophore of these
inhibitors shows there are three basic elements in their structures: a zinc bind group (ZBG) to chelate the zinc ion in the
catalytic site of the enzyme and a hydrophobic group are linked by a short fatty chain or an aromatic group [4]. One of
them, SAHA (trade name Zolinza), has been approved by FDA for cutaneous T-cell lymphoma patients in 2006 [5]. In
our lab, two new compounds (ja and jb) were found to show activities against HDACs (Fig. 1) and their IC50 value is
about 15 mmol/L. They were both synthesized from ferulic acid, a natural botanical product isolated from herb
Rhizoma Chuanxiong. Subsequently a new series of compounds were designed and synthesized based on ja and jb.
The hydrophobic groups of them are linked by five common amino acids (glycin, b-alanine, g-aminobutyric acid,
para-aminobenzoic acid and meta-aminobenzoic acid) because they contain a short fatty chain or an aromatic group
and their carboxyl group can be converted to be hydroximic acid group (ZBG) (Fig. 1). The synthetic route has been
shown in Scheme 1.
www.elsevier.com/locate/cclet
Available online at www.sciencedirect.com
Chinese Chemical Letters 19 (2008) 673–675
* Corresponding author.
E-mail address: [email protected] (W.F. Xu).
1001-8417/$ – see front matter # 2008 Wen Fang Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
doi:10.1016/j.cclet.2008.04.010
Esterification of ferulic acid with paratoluenesulfonic acid (PTS) got compound 1. Hydrogenation of compound 1
with 10%Pd–C at 1 atm got compound 2. Then it reacted with PhCH2Br and n-BuBr to prepare the ethers compound
3a and 3b by Williamson etherification method. Saponification of compounds 3a/4b got compound 4a/4b which were
treated with SOCl2 to prepare acyl chlorides and then reacted with five methylesters of five amino acids (glycin, b-
alanine, g-aminobutyric acid, para-aminobenzoic acid and meta-aminobenzoic acid) to prepare compounds 5-9a and
5-9b. Saponification of them got compounds 10-14a/10-14b which were treated with ClCOOBu-i and Et3N to prepare
J. Jiao et al. / Chinese Chemical Letters 19 (2008) 673–675674
Fig. 1. Design strategy.
Scheme 1. The synthetic route and structures of target compounds. (a) CH3OH, PTS; (b) H2, 10% Pd-C; (c) KOH, RBr, DMF; (d) NaOH, H2O,
EtOH; (e) SOCl2, THF, HCl�H2N-X-COOMe, Et3N; (f) ClCOOBu-i, Et3N, NH2OH�HCl, Et3N, THF.
anhydrides and then reacted with hydroxylamine in methanol to get target compounds J01–J10 [6] (Table 1).
Structures of all these compounds were confirmed by ESI MS and 1H NMR [7].
An HDAC colorimetric activity assay/drug discovery kit (AK-501, purchased from Biomol Research Laboratories)
was used in the HDACs activity assay. Firstly, HDACs source, substrate and Color de Lys Developer were diluted with
assay buffer. Then on the 96-wells plate we added HDACs extracts (5 mL/well), 10 mL various concentrations of
samples and 25 mL substrate. They were incubated at 37 8C for 30 min and then Color de Lys Developer (50 mL/well)
were added. After 15 min we measured the ultraviolet absorption of the wells on a microtiter-plate reader at 405 nm.
The %inhibition was calculated from the ultraviolet absorption readings of inhibited wells relative to those of control
wells. IC50 values are determined using a regression analysis of the concentration/inhibition data. The results of
activities are list in Table 1.
Compound J04 and J09 are nearly as potent as the control drug. The result will guide further research for discovery
of more potent HDACs inhibitors.
Acknowledgment
This work was supported by the National ‘‘863’’ Foundation (No. 2007AA02Z314).
References
[1] S. Minucci, P.G. Pelicci, Nature 6 (2006) 38.
[2] T.Y. Tim, Y.J. Bang, K.D. Robertson, Cell Cycle 1 (1) (2006) 14.
[3] G.F. Bi, G.S. Jiang, Cell. Mol. Immunol. 3 (4) (2006) 285.
[4] T.A. Miller, D.J. Witter, et al. J. Med. Chem. 46 (24) (2003) 5097.
[5] B.S. Mann, J.R. Johnson, et al. The Oncologist 12 (2007) 1247.
[6] Typical procedure for the synthesis of compounds J01-10: to a stirred solution of compound 13a (10 mmol) and Et3N (11 mmol) in THF, was
added isobutyl chloroformate (11 mmol) at �10 8C. The mixture was stirred for 5 min at the same temperature. A solution of hydroxylamine
(20 mmol) in dry methanol was added dropwise to the reaction mixture. The stirring was continued for 2 h at 0 8C (checked by TLC), and the
solvent was evaporated in vacuo. The residue was dissolved in CH2Cl2 and washed in 2 mol/L HCl and 10% NaHCO3 solution and brine, dried
over Na2SO4 concentration in vacuo gave the crude oil which was recrystallized by acetone to be the final product.
[7] Selected spectroscopic data: compound J04: white solid, yield 61%; mp: 193–195 8C; ESI MS: m/z [M + 1]+ 421.4; 1H NMR (DMSO-d6,
300 MHz, d ppm): 11.01 (s, 1H), 10.13 (s, 1H), 8.94 (s, 1H), 7.71–7.62 (q, 4H), 7.43–7.29 (m, 5H), 6.92 (d, 1H, J = 8.1), 6.88 (s, 1H), 6.73 (d, 1H,
J = 8.1), 5.02 (s, 2H), 3.73 (s, 3H), 2.85 (t, 2H, J = 7.5), 2.62 (t, 2H, J = 7.5).
J. Jiao et al. / Chinese Chemical Letters 19 (2008) 673–675 675
Table 1
The structures and HDACs inhibitory activities of compounds J01-10
Compd. R X HDACs IC50 (mmol/L)
J01 PhCH2 CH2 125.0
J02 PhCH2 (CH2)2 28.74
J03 PhCH2 (CH2)3 33.06
J04 PhCH2 1.78
J05 PhCH2 520.8
J06 n-Bu CH2 348.0
J07 n-Bu (CH2)2 11.76
J08 n-Bu (CH2)3 >1000
J09 n-Bu 4.04
J10 n-Bu >1000
Zolinza 1.28
