基于多芳环多吡啶配体的单功能铂配合物DNA结合研究

目的验证配体2,4,6-三[二(2-吡啶甲基)-氨甲基苯基]-1,3,5-三嗪(L4)配合物的DNA结合能力。方法合成一个多芳环多吡啶配体2,4,6-三[二(2-吡啶甲基)-氨甲基苯基]-1,3,5-三嗪(L4)。配体(L4)与Pt(DMSO)2Cl2反应得到配合物4,表征配合物,通过紫外、荧光和凝胶电泳的方法研究了配合物4的DNA结合能力。结果紫外和荧光实验表明该配合物均可与DNA嵌入结合,结合常数分别为2.1×104M-1、2.78×107M-1。凝胶电泳实验表明配合物可使DNA超螺旋形式完全解旋,有效扰乱DNA的二级结构。结论配体2,4,6-三[二(2-吡啶甲基)-氨甲基苯基]-1,3,5-三嗪(L4)配合物与DNA具有较强的结合能力,可以缓慢结合形成DNA的加合物,并且能够有效扰乱DNA构象。     

无抗生素质粒DNA扩增系统的探讨

质粒DNA疫苗在很多方面克服了传统疫苗和病毒载体疫苗的缺陷,本文对无抗生素质粒DNA扩增系统发展现状进行作一简要概述.     

改进的碱裂解法大规模提取质粒DNA

对质粒的碱裂解小量提取法进行了改进,改进的方法克服了以往质粒提取方法的RNA等杂质污染、操作烦琐费时、一般条件下不能大规模提取等问题,该方法操作简单、经济、实用且大规模提取,提取的质粒DNA得率稳定、质量好,符合大多数分子生物学常规实验的要求。     

家畜DNA疫苗免疫最新进展及应用前景

近年来的研究表明 ,应用 DNA疫苗免疫有下述优点 :免疫力持久 ;免疫应答谱广 (包括细胞免疫和体液免疫 ) ;制成的多价疫苗可同时诱导对多种病原体的免疫。本文介绍用马和奶牛作为模型 ,研究提高和诱导 DNA疫苗免疫应答的方法 ,发现同时免疫细胞因子编码质粒和抗原编码质粒能调节免疫应答强度和方向。表达抗原的细胞成分 (胞质成分、膜成分及胞外成分 )能决定所诱导的免疫应答的类型。粘膜表面的免疫应答是抗感染的关键 ,因此 ,已探索用不同的方法 (包括粘膜表面 )对动物进行 DNA疫苗接种 ,并阐述了提高 DNA疫苗免疫应答的前景     

多靶点配体与药物设计

综述有关多靶点配体药物设计的基本原理和方法,包括整合共有药效团法、轭合药效团法、可分解轭合药效团法及筛选法;并讨论多靶点配体与合理药物设计的关系以及设计中应注意的问题,为新药的研究与开发提供参考。     

生米卡链霉菌质粒DNA的分离及特性

用碱性裂解法从麦迪霉素产生菌(Str.mycarofaciens)10204中分离到质粒DNA,经琼脂糖凝胶电泳分析和电镜观察得到证实,分子量为11.5kb(7.6×10~6道尔顿),名为pSMVI。该质粒经酶切分析表明具有4个Bam HI位点和1个EcoRI位点,用质粒消除和转化实验,说明该质粒与麦迪霉素产生有一定的关系。     

质粒DNA气溶胶吸入诱导呼吸道粘膜免疫应答的可能性

本文介绍了有关质粒DNA气溶胶吸入免疫的研究概况,以及呼吸道免疫系统的研究 进展,并就质粒DNA气溶胶吸入免疫的可能性进行了分析,提出今后研究方向。     

菌体中大量抽提质粒DNA方法的改进

目的　建立简便、快捷的大量制备质粒的实验方法。方法　以文献报道方法为依据 ,将传统的质粒小量抽提的实验方法与大量抽提的实验方法有机结合 ,以琼脂糖凝胶电泳的方法证明了使用改进后方法的可行性。结果　使用该法可以一次大量地制备质粒DNA ( 690± 2 19) μg ,提取效力为 ( 1 4± 0 4) μg/ml菌液 ,并可直接用于酶切。结论　改进后的实验方法更加简便、快捷、高效 ,为分子生物研究中质粒的大量制备提供了更加实用的实验方法     

黄酮类活性成分对吸烟致质粒DNA损伤的保护作用

目的评价吸烟致质粒DNA损伤以及黄酮类活性成分对其损伤的防护作用。方法以自动吸烟机按照FTC协议吸烟产生的主流烟雾在线染毒溶液状态超螺旋构象质粒DNA,通过琼脂糖凝胶电泳分析DNA分子构象变化,检测DNA损伤程度及黄酮类活性成分黄芩素、槲皮素、丹参素钠及淫羊藿苷的防护作用。结果体外在线吸烟可致质粒DNA明显损伤,随吸烟剂量由0增加到8 puff及DNA与烟雾作用时间由0增加到1.3 h,DNA的断链分数F由0.15分别增加到0.24及0.29。即使在大剂量的烟雾攻击下,3种活性成分黄芩素、槲皮素与丹参素钠浓度〈0.001mol L-1时,均能够有效减轻吸烟对质粒DNA的损伤,与单独吸烟组相比,质粒DNA开环构象显著减少,在一定范围内,保护效果随着药物浓度的增加更加明显。结论黄芩素、槲皮素与丹参素钠对吸烟导致的DNA损伤具有较好的保护作用,其保护效果呈浓度依赖性。     

质粒DNA类基因治疗药物的研究现状及发展趋势

基因治疗是将外源基因导入人体以纠正基因缺陷的方法,通过转录和翻译实现对细胞基因表达的调控,从而合成特异性蛋白治疗相关疾病。质粒DNA是经基因工程改造过的环状DNA分子,其结构简单,具有自主复制能力,可以携带治疗基因导入人体细胞,被广泛用于基因治疗的研究中。目前已上市及正处于临床研究的基于质粒DNA的基因药物包括cambiogenplasmid、Tavo等。对遗传病、恶性肿瘤等适应证,质粒DNA的基因治疗比传统的治疗方案有明显优势。CRISPR-Cas9等相关的质粒基因编辑技术成为质粒DNA类基因治疗的一大研发趋势,基因枪、聚合物纳米载体等递送系统以透皮给药、静脉注射等方式为质粒DNA导入体内提供了更多可能。基于质粒DNA类的基因治疗已成为基因治疗领域的一种理想技术手段。     

Synthesis,antitumor activity evaluation,and DNA‐binding study of coumarin‐based agents

A novel series of coumarin‐thiadiazole heterocycle derivatives was synthesized by the nucleophilic substitution reaction. The synthesized compounds were structurally verified by IR, ¹H NMR, ¹³C NMR, mass spectra, and elemental analyses. The antitumor activity of the synthesized compounds was evaluated through DNA binding assays and the 60‐cell line panel according to the US NCI‐DTP protocol or a selection of human tumor cell lines: breast cancer (MCF‐7), liver cancer (HepG‐2), and colorectal cancer (HCT‐116). Most of the compounds had better DNA/ethidium bromide fluorescence quenching rather than methyl green displacement, suggesting superior DNA intercalation over DNA groove binding. Compounds 8 and 14b showed the best quenching effect with K_SV = 4.27 × 10⁵ M^?1. Moreover, the results for compounds 8 , 4c , and 4e revealed a possible dual DNA binding mode with the intercalation to be superior, with K_SV 4.27 × 10⁵, 3.96 × 10⁵, and 3.51 × 10⁵ M^?1, respectively, compared to 42%, 45%, and 43% methyl green displacement, respectively. Out of the 60‐cell line panel, the leukemia HL‐60 cell line was the most susceptible to growth inhibition when treated with 14a , resulting in 61% growth, followed by the lung carcinoma cell line NCI‐H522 showing 67% growth when treated with 9 . Moreover, compound 10c had an IC₅₀ value of 24.9 μg/mL against the HepG‐2 cell line.

     

核受体及其配体的研究进展

核受体（nudear receptors，NRs）是位于细胞核内或与相应配体结合后由胞浆转到细胞核内的一大类受体，属于配体活化的转录因子。对其特异正性或负性的调控是预防和治疗许多疾病的重要手段。该文对几种重要的核受体配体的功能及其构效关系研究进行综述。     

Specific sequestering agents for the actinides. 16. Synthesis and initial biological testing of polydentate oxohydroxypyridinecarboxylate ligands

Chemical and biological similarities of plutonium(IV) and iron(III) suggested that octadentate ligands containing hydroxamate or catecholate functional groups, which are found in microbial iron chelating agents (siderophores), would be effective and relatively selective complexing agents for actinide(IV) ions. However, their usefulness for in vivo chelation of actinide(IV) is limited, because catechol and hydroxamate are such weak acids that the potential for octadentate binding of actinide(IV) cannot be achieved at physiological pH. The structurally similar monoprotic and more acidic 1-hydroxy-2(1H)-pyridinone (1,2-HOPO) group was, therefore, incorporated into multidentate ligands. Treatment of 1,2-dihydro-1-hydroxy-2-oxopyridine-6-carboxylic acid (5) with phosgene in THF solution gives the active ester poly[1,2-dihydro-1,2-dioxopyridine-6-carboxylate], which upon treatment with excess anhydrous dimethylamine gave a 60% yield of N,N-dimethyl-1,2-dihydro-1-hydroxy-2-oxopyridine-6-carboxamide (6). A similarly reactive intermediate was prepared from 5 and an equimolar amount of phosgene in N,N-dimethylacetamide. Combined in situ with 1,3-propanediamine, benzylamine, spermine, spermidine, 1,3,5-tris(aminomethyl)benzene, or desferrioxamine B and excess triethylamine, the latter intermediate gave the corresponding amides in isolated yields ranging from 16% to 60%. The free ligands, their Zn(II) complexes, and the ferric complex of 3,4,3-LIHOPO were administered to mice [30 mumol/kg intraperitoneally 1 h after Pu(IV)-238 citrate, kill at 24 h]. Net Pu removal [Pu excretion (treated)-PU excretion (control)], expressed as percent of injected Pu, was as follows: Na salts and Zn(II) complexes, respectively, of 3-LIHOPO (54, 56), 3,4-LIHOPO (58, 60), 3,4,3-LIHOPO (73, 76); Na salts of MEHOPO (46), DFO-HOPO (78); Fe(III) complex of 3,4,3-LIHOPO (79). DFO-HOPO and 3,4,3-LIHOPO and its Zn(II) and Fe(III) complexes promoted significantly more Pu excretion than CaNa3-DTPA (61% of injected Pu). Preliminary findings on the acute toxicity of the poly(HOPO) ligands and HOPO monomers are presented in an appendix. The biological data indicate strongly that the aqueous solubility and relatively high acidity of the octadentate HOPO ligands, 3,4,3-LIHOPO and DFO-HOPO allow them to form complete eight-coordinate complexes with Pu(IV) ion.     

Novel estrogen receptor ligands and their structure–activity relationship evaluated by scintillation proximity assay for high‐throughput screening

The estrogen receptor (ER) is an important drug target with allosteric characteristics that binds orthotopic hormones and other ligands. A recently developed scintillation proximity (SPA)‐based assay for high‐throughput screening (HTS) of compound libraries was used to identify novel estrogen receptor ligands that might have ER subtype selective binding activity. Radioligand binding was determined in a multi‐detector scintillation counter designed for microtitration plates. Equilibrium binding experiments and kinetic competition tests were performed with [³H]‐estradiol and human ERα and ERβ receptors. A library of 6,000 structurally diverse compounds was screened. From this, several novel ligands were identified that showed pronounced subtype‐selective differences in ligand binding for ERα and ERβ. The observed equilibrium dissociation constant (K_d) for the binding of [³H]estradiol to ERα and ERβ receptors were approximately 0.25 and 0.64 nM, respectively. When 17β‐estradiol, raloxifene and daidzein were tested for binding affinity to ERα in a competition assay, the IC₅₀ values were 0.34, 1.31, and 75.6 nM, respectively. When tested for binding affinity to ERβ, the IC₅₀ values were 1.05, 11.4, and 10.6 nM, respectively. The results obtained show that the methodology is valid in comparison to previously published data regarding estradiol and other standard compounds (raloxifene and daidzein) binding characteristics of estrogen receptors. The assay is also well suited to applied research as a tool in HTS of compound libraries in the search of ER ligands. Several novel active compounds were identified and selected as potent ER subtype ligands. Drug Dev Res 64:203–212, 2005. © 2005 Wiley‐Liss, Inc.     

Synthesis of novel gefitinib‐based derivatives and their anticancer activity

Drug latentiation is a process of modifying a drug molecule structurally to improve its binding affinity as well as increasing the drug–receptor interactions and potentiate its therapeutic potential. In the quest for discovering more potent epidermal growth factor receptor (EGFR) inhibitors, gefitinib‐based derivatives were designed by simple structural modification at the secondary amine of gefitinib by N‐alkylation. Three gefitinib derivatives (gefitinib‐NB, ‐NP, and ‐NIP) were synthesized by N‐alkylation and phase transfer catalysis. Structural characterization, physicochemical parameters such as solubility, log P, and p K _a were determined. Molecular docking studies were carried out to investigate the binding interactions at the active site. Further drug‐bovine serum albumin (BSA) protein and drug‐calf thymus (CT) DNA interactions were performed to understand the pharmacokinetics of the synthesized derivatives. All the compounds were screened for preliminary in vitro cytotoxic activity against A549, A431 lung, and MDA‐MB‐231 breast cancer cell lines by MTT assay. The gefitinib‐NP and gefitinib‐NB derivatives exhibited strong cytotoxic activity compared with gefitinib. They also showed higher drug‐BSA and drug‐DNA interactions. Molecular docking studies showed the orientation and binding interactions with the EGFR as well as with BSA and CT DNA. The results establish a strong correlation between the experimental and molecular docking studies. EGFR inhibition studies were also carried out for the derivatives and we identified the NP derivative of gefitinib as a potential lead compound. The gefitinib‐based derivatives reported herein are cytotoxic agents and can be tested for further pharmacokinetic profiles and toxicity studies which might be helpful for designing more potent gefitinib‐based derivatives in the future.     

Unsymmetrical Oxovanadium Complexes Derived from Salicylaldehyde and Phenanthroline: Synthesis,DNA Interactions,and Antitumor Activities

Two unsymmetrical oxovanadium complexes incorporating salicylaldehyde derivate and phenanthroline [VO(DESAA)(phen)] ( 1 ), (DESAA = 4‐(diethylamino)salicylaldehyde anthranilic acid, phen = phenanthroline) and [VO(CLSAA)(phen)] ( 2 ), (CLSAA = 5‐chlorosalicylaldehyde anthranilic acid)] have been synthesized and characterized. The interactions of the complexes with CT‐DNA were studied using different techniques. Complexes 1 and 2 interact with CT‐DNA by intercalative modes and can efficiently cleave pBR322 DNA after light irradiation. The two complexes showed high cytotoxic activities against myeloma cell (Ag8.653) and gliomas cell (U251) lines. Interestingly, complex 1 exhibited greater antitumor efficiency, larger binding affinity with CT‐DNA, and better cleaving ability than those of complex 2 . In addition, their antitumor mechanism has been analyzed by using cell cycle analysis, apoptosis, and Annexin V‐FITC/PI assay. The results showed that complex 1 can cause G2/M‐phase arrest of the cell cycle, exhibit a significantly induced apoptosis in Ag8.653 cells, and display typical morphological apoptotic characteristics. These complexes induced proliferative suppression of Ag8.653 cells via the induction of apoptosis.     

A novel series of chlorinated plastoquinone analogs: Design,synthesis, and evaluation of anticancer activity

Herein, we report the synthesis and cytotoxic effects of novel chlorinated plastoquinone analogs ( ABQ1–17 ) against different leukemic cells. Compounds ABQ3 , ABQ11 , and ABQ12 demonstrated a pronounced antiproliferative effect against chronic myelogenous leukemia (CML) K562 cell line with IC₅₀ values of 0.82 ± 0.07, 0.28 ± 0.03, and 0.98 ± 0.22 μM, respectively. Among them, ABQ11 showed approximately three times higher selectivity than imatinib on CML. ABQ11 ‐treated CML cells induced significant apoptosis at low concentration. Inhibitory effect of ABQ11 against eight different tyrosine kinases, including ABL1, was investigated. ABQ11 inhibited ABL1 with IC₅₀ value of 13.12 ± 1.71 μM, indicating that the moderate inhibition of ABL1 kinase is just an in‐part mechanism of its outstanding cellular activity. Molecular docking of ABQ11 into ABL1 kinase ATP‐binding pocket revealed the formation of some key interactions. Furthermore, DNA cleavage assay showed that ABQ11 strongly disintegrated DNA at 1 μM concentration in the presence of iron (II) complex system, assuming that the major mechanism for the anticancer effects of ABQ11 is DNA cleavage. In silico ADMET prediction revealed that ABQ11 is a drug‐like small molecule with a favorable safety profile. Taken together, ABQ11 is a potential antiproliferative hit compound that exhibits unique cytotoxic activity distinct from imatinib.     

Synthesis,Characterization, and in Vitro Evaluation of a New TSPO-Selective Bifunctional Chelate Ligand

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Synthesis of new 4-heteroaryl-2-phenylquinolines and their pharmacological activity as NK-2/NK-3 receptor ligands

Substituted 4-heteroaryl-2-phenylquinolines were synthesized and tested on NK-2 and NK-3 receptors in order to get a better insight in the structure-activity relationship. On the whole, these molecules, which can be regarded as bioisosters of the NK-3 antagonist SB 218795, displayed a lower activity than the template. Ring electronic distribution and H-bond donor and acceptor positions played some role in selectivity, 2-imidazolyl substituted 2a showing affinity mainly towards NK-3 while 3-pyrazolyl substituted 4 displayed a preferential interaction with NK-2 receptor. Structural characterization of the synthesized compounds was achieved by NMR and mass techniques. Bidimensional 1H-NOESY experiments were a helpful tool for the assignment of the isomeric structures of compounds 9 and llb-c.