Toxicological evaluation of an apicidin derivative, histone deacetylase inhibitor SD-2007 in mice

SD-2007 is a new derivative of apicidin, an anti-parasitic agent and a histone deacetylase (HDAC) inhibitor. A subacute toxicological evaluation of SD-2007 was investigated for 2 weeks in ICR mice. After oral administration of SD-2007 (0, 0.2, 1, 5 or 25 mg/mouse), the clinical signs, mortalities, body weight changes, blood biochemical parameters, absolute and relative organ weights were examined. One day after the administration of SD-2007, excretion of soft feces in 1 and 5 mg/head groups, and one male in 25 mg/mouse group developed diarrhea, but theses complications were disappeared two days after administration. No mortalities were observed in animals up to 25 mg/mouse (LD₅₀, >25 mg/kg), but absolute and relative weights of testes were significantly lower at the highest dose group (25 mg/mouse) and serum LDH and glucose levels were elevated in male mice. In addition, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) activities were reduced in female mice at all dosages. These data suggest that SD- 2007 may be sex specific and be toxic to the male reproductive organ, and thus our findings require further investigation and in particular chronic toxicological investigations should be investigated.     

苯甲酰胺类组蛋白去乙酰化酶抑制剂的合成及 抗肿瘤细胞增殖活性

目的 针对组蛋白去乙酰化酶（HDAC）的结构特点,设计合成一系列化合物并进行体外抗肿瘤活性评价,为进一步优化设计提供指导。方法 以 2-羟基-4-硝基苯甲醛为原料,经环合、还原、与芳醛衍生物反应、水解后,在N,N-碳酰二咪唑存在下经缩合反应合成目标化合物。结果与结论 共合成了11个新苯甲酰胺类衍生物,化合物的结构经质谱、核磁共振氢谱确证;体外抗肿瘤活性评价结果表明,其中 4 个化合物（4b、4c、4d、4h）对肿瘤细胞具有显著的增殖抑制活性,化合物4h的活性最好,它对 HL60、MCF-7、A549 肿瘤细胞的 IC₅₀值分别为2.81、＞50、4.79 μmol·L^-1。     

组蛋白去乙酰化酶抑制药研究现状

组蛋白去乙酰化酶抑制药具有的锌指结构与组蛋白乙酰化赖氨酸残基侧链结构相似,可通过竞争性抑制组蛋白去乙酰化酶活性而提高组蛋白乙酰化水平,改变特定基因的转录与表达水平,抑制细胞增殖,诱导细胞分化与凋亡,从而发挥多种药理作用尤其是抗癌作用。多种组蛋白去乙酰化酶抑制药已得到了深入的研究,并在临床试验中显示出良好的治疗效果。     

Pharmacokinetics of a novel histone deacetylase inhibitor, apicidin, in rats

This study is the first report of the pharmacokinetics of a novel histone deacetylase inhibitor, apicidin, in rats after i.v. and oral administration. Apicidin was injected intravenously at doses of 0.5, 1.0, 2.0 and 4.0 mg/kg. The terminal elimination half-life (t1/2), systemic clearance (Cl) and steady-state volume of distribution (Vss) remained unaltered as a function of dose, with values in the range 0.8-1.1 h, 59.6-68.0 ml/min/kg and 2.4-2.7 l/kg, respectively. Whereas, the initial serum concentration (C0) and AUC increased linearly as the dose was increased. Taken together, the pharmacokinetics of apicidin were linear over the i.v. dose range studied. The extent of urinary and biliary excretion of apicidin was minimal (0.017%-0.020% and 0.049% +/- 0.016%, respectively). Oral pharmacokinetic studies were conducted in fasting and non-fasting groups of rats at a dose of 10 mg/kg. The Tmax, Cl/F and Vz/F were in the range 0.9-1.1 h, 520.3-621.2 ml/min/kg and 67.6-84.4 l/kg, respectively. No significant difference was observed in the oral absorption profiles between the two groups of rats. Apicidin was poorly absorbed, with the absolute oral bioavailability of 19.3% and 14.2% in fasting and non-fasting rats.     

Synthesis of apicidin-derived quinolone derivatives: parasite-selective histone deacetylase inhibitors and antiproliferative agents

Apicidin's indole was efficiently converted into a series of N-substituted quinolone derivatives by indole N-alkylation followed by a two-step, one-pot, ozonolysis/aldol condensation protocol. The new quinolones exhibited good parasite selectivity and potency both at the level of their molecular target, histone deacetylase, and in their whole cell antiproliferative activity in vitro.     

Anticancer activities of histone deacetylase inhibitors

Histone deacetylases (HDACs) are enzymes involved in the remodelling of chromatin, and have a key role in the epigenetic regulation of gene expression. In addition, the activity of non-histone proteins can be regulated through HDAC-mediated hypo-acetylation. In recent years, inhibition of HDACs has emerged as a potential strategy to reverse aberrant epigenetic changes associated with cancer, and several classes of HDAC inhibitors have been found to have potent and specific anticancer activities in preclinical studies. However, such studies have also indicated that the effects of HDAC inhibitors could be considerably broader and more complicated than originally understood. Here we summarize recent advances in the understanding of the molecular events that underlie the anticancer effects of HDAC inhibitors, and discuss how such information could be used in optimizing the development and application of these agents in the clinic, either as monotherapies or in combination with other anticancer drugs.     

Patent status of histone deacetylase inhibitors

Histone deacetylase (HDAC) has emerged as an important therapeutic target for the treatment of cancer and other diseases. Several HDAC inhibitors that target class I and II HDACs are currently in clinical trials. The initial results from these studies indicate that HDAC inhibitors show great promise for the treatment of cancer. To date, more than 30 research organisations are named as applicants on published patent applications claiming structures of HDAC inhibitors. This review summarises the patent literature published from mid-2002 to early 2004 containing claims directed towards HDAC inhibitor structures, together with discussion of the related primary literature.     

Small molecule inhibitors of histone deacetylase

This patent deals with novel histone deacetylase (HDAC) inhibitors and methods of their use for treating cell proliferative diseases or conditions, such as cancer, restenosis and psoriasis. Claimed herein are pharmaceutical compositions comprising small molecule HDAC inhibitors as the active ingredient, optionally combined with the use of an antisense oligonucleotide that inhibits HDAC expression. The claimed compounds were synthesised according to given reaction schemes and tested for their inhibition of HDAC enzymatic activity using nuclear extracts from cancer cells (pooled HDACs) and recombinant human HDAC1. An exemplified compound is stated to have caused a significant reduction in tumour weight and volume relative to saline-treated controls in BALB/c nude mice subcutaneously bearing A549 human lung carcinoma cells.     

组蛋白去乙酰化酶抑制剂的研究进展

组蛋白去乙酰化酶（HDACs）是一类对染色体的结构修饰和基因表达调控发挥着重要作用的蛋白酶,与肿瘤的发生发展关系密切。组蛋白去乙酰化酶抑制剂（HDACIs）在抗肿瘤药物的开发中具有重要意义。本文对HDACs分子结构、HDACs与肿瘤的关系、HDACIs化学结构及其目前主要的设计思路、构效关系进行综述。     

新型苯磺酰胺类组蛋白去乙酰化酶抑制剂的合成及其抗肿瘤活性研究

目的设计合成新型苯甲酰胺类组蛋白去乙酰化酶抑制剂,并探讨此类HDAC抑制剂的构效关系。方法以HDAC抑制剂恩替司他(entinostat,MS-275)为先导化合物,对其离子结合区与表面识别区进行改造,根据HDACs活性中心的结构特点,设计并合成了系列苯磺酰胺化合物。首先,对甲苯磺酰氯与邻硝基苯胺缩合得到含磺酰胺基的化合物,然后,经溴代、叠氮化、水解得到氨基化合物,最后与取代酰氯缩合并还原得到目标化合物。采用SRB法,对PC3、HL-60、A549三种肿瘤细胞株进行体外抗肿瘤活性筛选。结果与结论合成了11个未见文献报道的新化合物,化合物的结构经质谱、核磁共振氢谱、碳谱确证;体外抗肿瘤活性评价结果表明,化合物8j和8k对HL-60、PC3肿瘤细胞株具有增殖抑制活性,化合物8j对HL-60细胞抑制作用的IC50值为31.329μmol·L-1、化合物8k对PC3肿瘤细胞抑制作用的IC50值为3.612μmol·L-1。     

4-哌嗪喹唑啉苯甲酰胺类化合物的设计、合成及抗肿瘤活性研究

目的寻找新型苯甲酰胺类组蛋白去乙酰化酶(HDACs)抑制剂,探讨其初步构效关系。方法以恩替司他(MS-275)为先导结构,对其酶表面识别区、链接区及锌离子结合区进行改造,设计并合成了系列4-哌嗪喹唑啉苯甲酰胺类化合物。以取代4-羟基喹唑啉为原料,经氯代、氨解、水解制备苯甲酸类衍生物,然后与邻苯二胺或4-氟邻苯二胺经缩合反应制备目标化合物7a~7h;经体外组蛋白去乙酰化酶1抑制活性试验及对人结肠癌细胞HCT-116的抗增殖活性试验,进行目标化合物的活性评价。结果与结论共合成8个未见文献报道的新化合物,结构经质谱及核磁共振氢谱确认。体外初步活性试验表明,目标化合物均具有HDAC1酶抑制活性及抗肿瘤细胞增殖活性。与MS-275相比,目标化合物对HDAC1酶抑制活性减弱,但化合物体外对人结肠癌细胞HCT-116的抗增殖活性却优于或相当于MS-275,其中化合物7g对HCT-116抑制作用的IC50值为0.245μmol·L-1,具有进一步研究价值。     

Current patent status of histone deacetylase inhibitors

Histone deacetylases (HDACs) alter the acetylation status of the amino terminal region of histone proteins, which are complexed with DNA in the nucleosome. This acetylation status determines DNA accessibility and, in turn, influences gene expression. The inappropriate recruitment of HDACs may be one mechanism by which oncogenes can alter gene expression in favour of excessive proliferation and this makes inhibition of HDACs a potential target for the development of small molecule anticancer agents. There are several HDAC inhibitors currently in cancer clinical trials and approximately twenty research organisations with ongoing programmes in this field. This review examines the HDAC patent literature from 1997 to mid-2002 with some discussion of primary literature and older citations when appropriate. The review is divided into the structural classes of known HDAC inhibitors that include the non-peptidic hydroxamic acids, cyclic peptides, benzamides, butyric acid analogues and electrophilic ketones.     

Structure-based optimization of phenylbutyrate-derived histone deacetylase inhibitors

Previously, we developed a strategy to develop a novel class of histone deacetylase (HDAC) inhibitors by tethering short-chain fatty acids with Zn(2+)-chelating motifs, which led to N-hydroxy-4-(4-phenylbutyryl-amino)benzamide (HTPB), a hydroxamate-tethered phenylbutyrate derivative with sub-micromolar potency in inhibiting HDAC activity and cancer cell proliferation. In this study, we carried out structure-based optimization of HTPB by using the framework generated by the structure of histone deacetylase-like protein (HDLP)-trichostatin A (TSA) complexes. Docking of HTPB into the HDLP binding domain suggested that the hydrophobic microenvironment encompassed by Phe-198 and Phe-200 could be exploited for structural optimization. This premise was corroborated by the greater potency of (S)-(+)-N-hydroxy-4-(3-methyl-2-phenylbutyrylamino)-benzamide [(S)-11] (IC(50) in HDAC inhibition, 16 nM), of which the isopropyl moiety was favorable in interacting with this hydrophobic motif. (S)-11 at concentrations as low as 0.1 microM was effective in causing histone hyperacetylation and p21(WAF/CIP1) overexpression and suppressing proliferation in cancer cells.     

Rational design of non-hydroxamate histone deacetylase inhibitors

While most inhibitors of histone deacetylases (HDACs) are hydroxamic acid derivatives, several non-hydroxamates have recently been developed as inhibitors and attracted quite a deal of attention. In this review, we present the rational design, inhibitory effect and antiproliferative activity of non-hydroxamate HDAC inhibitors.     

含吡嗪环的苯甲酰胺类HDAC抑制剂的合成及其抗肿瘤活性

目的设计合成具有抗肿瘤活性的新型苯甲酰胺类组蛋白去乙酰化酶抑制剂。方法 4-氨甲基苯甲酸酯化后与2,6-二氯吡嗪反应得到中间体,再经过Suzuki反应后与相应的取代苯硼酸偶联,在CDI的作用下与相应的苯胺反应得到目标化合物。结果与结论合成了12个未见文献报道的新化合物,其结构经MS、1H-NMR谱确证。化合物4a、4b、4d、4i和4k对人急性白血病细胞(HL60)和人乳腺癌细胞(M CF-7)的抑制活性与阳性对照物MS-275相比,活性相当或有较为显著的提高,可进行进一步研究。