High throughput screening assay for UDP-glucuronosyltransferase 1A1 glucuronidation profiling

Development of high throughput screening (HTS) assays for evaluation of a compound's toxicity and potential for drug-drug interactions is a critical step towards production of better drug candidates and cost reduction in the drug development process. HTS assays for drug metabolism mediated by cytochrome P450s are now routinely used in compound library characterization and for computer modeling studies. However, development and application of HTS assays involving UDP-glucuronosyltransferases (UGTs) are lagging behind. Here we describe the development of a fluorescence-based HTS assay for UGT1A1 using recombinant enzyme and fluorescent substrate in the presence of an aqueous solution of PreserveX-QML (QBI Life Sciences, Madison, WI) polymeric micelles, acting as a stabilizer and a blocker of nonspecific interactions. The data include assay characteristics in 384-well plate format obtained with robotic liquid handling equipment and structures of hits (assay modifiers) obtained from the screening of a small molecule library at the University of Wisconsin HTS screening facility. The application of the assay for predicting UGT-related drug-drug interactions and building pharmacophore models, as well as the effects of polymeric micelles on the assay performance and compound promiscuity, is discussed.     

A novel high throughput screening assay for HCV NS3 helicase activity

A novel assay for measurement of Hepatitis C virus (HCV) NS3 helicase activity was developed using Flashplate technology. This assay involves the use of a DNA duplex substrate and recombinant HCV NS3 produced in Escherichia coli. The DNA duplex consisted of a pair of oligonucleotides, one biotinylated, the other radiolabeled at their respective 5' termini. This DNA duplex was immobilized, via the biotin molecule, on the surface of a neutravidin-coated SMP103 Flashplate (NEN Life Science Products). Helicase activity results in the release of the radiolabeled oligonucleotide, which translates in signal reduction with respect to control wells. Biochemical characterization of the HCV NS3 helicase activity was performed using this assay. We demonstrated that the NS3-mediated unwinding is proportional to both the amount of DNA substrate in the well, and to the NS3 concentration in the reaction. Most of the NS3-mediated unwinding was achieved in the initial 60 min of incubation. As expected the reactions were ATP-dependent and found to be affected by the concentration of MgCl(2), MnCl(2), KCl, EDTA, and by pH. We found this assay to be highly reproducible since only slight variation was observed when a total of 68 helicase reactions were performed on one plate. Therefore, this Flashplate helicase assay is fast, convenient and reproducible. These criteria make it suitable for high throughput screening of potential NS3 helicase inhibitors.     

Nanoliter homogenous ultra-high throughput screening microarray for lead discoveries and IC50 profiling

Microfluidic technologies offer the potential for highly productive and low-cost ultra-high throughput screening and high throughput selectivity profiling. Such technologies need to provide the flexibility of plate-based assays as well as be less expensive to operate. Presented here is a unique microarray system (the Reaction Biology [Malvern, PA] DiscoveryDot), which runs over 6,000 homogeneous reactions per 1" x 3" microarray using chemical libraries or compound dilutions printed in 1-nl volumes. A simple and rapid piezo-activation method delivers from 30 to 300 pl of biochemical targets and detector chemistries to each reaction. The fluorescent signals are detected and analyzed with conventional microarray scanners and software. The DiscoveryDot platform is highly customizable, and reduces consumption of targets and reaction chemistries by >40-fold and the consumption of compounds by >10,000-fold, compared to 384-well plate assay. We demonstrate here that the DiscoveryDot platform is compatible with conventional large-volume well-based reactions, with a Z' factor of >0.6 for many enzymes, such as the caspase family enzymes, matrix metalloproteinase, serine proteases, kinases, and histone deacetylases. The platform is well equipped for 50% inhibitory concentration (IC50) profiling studies of enzyme inhibitors, with up to 10 dilution conditions of each test compound printed in duplicate, and each microarray chip can generate over 300 IC50 measurements against a given target.     

G-蛋白偶联受体的功能测定和高通量药物筛选

G 蛋白偶联受体家族是药物开发中最大的一类药物靶点 ,高通量药物筛选是开发药物早期阶段的最重要工具之一。根据G 蛋白偶联受体与配体结合及激发的信号通路 ,人们设计了各种可行的功能测试方法 ,用于G 蛋白偶联受体为药靶的高通量药物筛选 ,如 :微体积荧光数字图像测定技术 (Fluorometicmicrovolumeassaytechnology ,FMAT)、荧光偏振 (Fluoresencepolarization ,FP)、竞争性ELISA (Com petitiveenzyme linkedimmunosorbent)、闪烁邻近测定法(Scintillation proximityassay ,SPA)、载黑色素细胞测定法(Melanophoreassay)、报告基因测定法 (Reportergeneassay)和钙离子测定法等测定方法。在这些方法中 ,报告基因测定法和钙离子测定法占了主导地位。非放射性、无需底物和辅助剂的报告基因测定方法和荧光钙离子指示剂的钙离子测定方法可能是将来G 蛋白偶联受体的功能分析和高通量药物筛选的发展方向     

A beta-lactamase-dependent Gal4-estrogen receptor beta transactivation assay for the ultra-high throughput screening of estrogen receptor beta agonists in a 3456-well format

Estrogen action is mediated via two estrogen receptor (ER) subtypes, ERalpha and ERbeta. Selective ER modulators with balanced high affinity for ERalpha and ERbeta have been developed as therapeutics for the treatment of a variety of diseases, including hormone-responsive breast cancer and osteoporosis. Recent data based primarily on the evaluation of ER-knockout mice have revealed that ERalpha and ERbeta may regulate separate and distinct biological processes. The identification of ERbeta specific ligands could further enhance our understanding of ERbeta biology. In addition, compounds targeting ERbeta may prove useful as therapeutic agents with activity profiles distinguishable from that of estradiol. To discover novel selective ligands for ERbeta, we developed and characterized a cell-based Gal4-ERbeta beta-lactamase reporter gene assay (GERTA) in CHO cells for the ligand-induced activation of the human ERbeta. The sensitivity and selectivity of this assay were found to be comparable to those of an ER ligand-binding assay. The assay was optimized for screening in an ultra high throughput 3456-well nanoplate format and was successfully used to screen a large compound collection for ERbeta agonists. Compounds identified in a primary screen were tested in an in vitro ligand-binding assay to characterize further the selectivity and potency for ERbeta.     

极化荧光在高通量药物筛选中的应用

1　前言基于荧光技术的检测分析方法是近年来被应用于药物高通量筛选 (high throughputscreening,HTS)的重要方法之一,荧光检测方法具有灵敏度高、方法简便的优点,目前应用于HTS的荧光技术包括均相时间分辨荧光分析法 (homogeneoustimeresolvedfluorescence,HTRF),荧光共振能量     

以微管蛋白为靶的高通量药物筛选方法的建立与应用

目的：以微管蛋白为靶建立高通量筛选（HTS）模型，以便有效地发现抗肿瘤化合物。方法：细胞培养与免疫荧光技术。结果：以常规的免疫组化（玻片）方法为基础优化实验条件，在96孔板上建立了以微管蛋白为靶点的高通量药物筛选模型；抗肿瘤药物紫杉醇和秋水仙碱作用于人肝癌HepG2细胞后，细胞的免疫荧光强度发生了明显的可检测的变化，间接反映药物对细胞徽管蛋白聚合／解聚作用的影响，与理论预测结果一致。结论：基于人肿瘤细胞的以徽管蛋白为靶点的高通量筛选方法可用于抗肿瘤化合物的筛选。     

Miniaturized, ultra-high throughput screening of tyrosine kinases using homogeneous, competitive fluorescence immunoassays

Assay miniaturization and the implementation of high-density 1,536-microwell screening increase the speed and efficiency of screening and lead discovery. To serve this need, a platform of miniaturizable assay technologies has been assembled for specific biological targets. This platform will enable initiation and completion of uHTS screens in a straightforward and expeditious manner. Although faster primary screening does contribute to a reduction in timelines, the process of assay development can become a bottleneck. Assay technologies that do not require the use of target-specific reagents can reduce the time necessary for assay development. Assays that measure inhibition of tyrosine kinases can be configured in a competitive format where only the enzyme itself is specific to the assay. In this context, several technologies, including time-resolved fluorometry (also known as DELFIA), time-resolved fluorescence resonance energy transfer (also known as LANCE( trade mark )), fluorescence polarization, enzyme fragmentation complementation assay, and confocal laser scanning imaging, were examined. Quality parameters such as assay reproducibility, signal:background ratio, Z factor, and assay sensitivity were compared. Additionally, the relative merits of each of these technologies are assessed in terms of assay miniaturization, ease of development, ultimate screening capability, efficiency, and cost.     

Fluorescence polarization assay for identification of lox-1 ligand through high throughput screening

AIM: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) was identified as special receptor for oxidized lowdensity lipoprotein (oxLDL) in endothelial cells. LOX-1 critically mediated oxLDL stimulating the progression of atherosclerosis. Identification and discovery LOX-1 antagonist to therapy atherosclerosis will be an interested exploration. METHODS: Human LOX-1 was expressed as a His-fusion inbacteria and purified by metal ion affinity and gel filtration     

P-gp蛋白功能抑制剂高通量筛选模型的建立与应用

目的建立高通量筛选模型,寻找疗效好、毒副作用小的肿瘤多药耐药逆转剂。方法以罗丹明123荧光染料胞内积累实验为基础,建立基于细胞水平的高通量筛选模型,对480个中药样品进行了高通量筛选,并采用剂量—活性依赖实验和抗性增敏实验验证阳性样品。结果模型Z′因子为0.72,筛选得到2个中药样品。结论建立的P-gp蛋白功能抑制剂高通量筛选模型稳定性好,灵敏度高,筛选得到的2种中药样品具有较好的P-gp蛋白功能抑制活性。     

白细胞弹性蛋白酶抑制剂筛选模型的建立及抑制剂F02ZA-2554A的研究

利用人源的白细胞弹性蛋白酶建立了一种快速、微量、灵敏的高通量体外筛选方法。利用该模型从微生物菌种库菌株的次生代谢产物中筛选得到一阳性真菌F02ZA-2554。该菌株发酵液经有机溶剂提取、硅胶柱层析、及HPLCODS反相柱层析等活性跟踪下的分离纯化，得到活性化合物F02ZA-2554A，该化合物对白细胞弹性蛋白酶有中等强度的抑制活性，其IC20为32．4μmol／L。通过对该化合物的紫外、质谱、核磁等理化分析，确定该化合物为葸醌类化合物中的大黄素甲醚（physcion），该化合物的抗炎活性属首次报道。     

Functional characterisation of human glycine receptors in a fluorescence-based high throughput screening assay

The human glycine receptor subtypes alpha1beta and alpha2 have been expressed stably in HEK293 cells, and the functional characteristics of the receptors have been characterised in the FLIPR Membrane Potential Assay. The pharmacological properties obtained for nine standard ligands at the two receptors in this assay were found to be in good agreement with those from electrophysiology studies of the receptors expressed in Xenopus oocytes or mammalian cell lines. Hence, this high throughput screening assay will be of great use in future pharmacological studies of glycine receptors, particular in the search for novel compound structures acting at them.     

Development of a homogeneous calcium mobilization assay for high throughput screening of mas-related gene receptor agonists

AIM: To develop homogeneous calcium mobilization assay for high-throughput screening (HTS) of mas-related gene (Mrg) receptor agonists. METHODS: CHO-K1 cells stably expressing the full-length MrgD receptor and a calcium-sensitive dye were used to develop an HTS assay based on intracellular calcium influx. This method was applied to large-scale screening of a library containing 8000 synthetic compounds and natural product extracts. cAMP measurements were carried out to verify the bioactivities of the hits found by the calcium mobilization assay. Similar approaches were also employed in the identification of the MrgA1 receptor agonists following HTS of 16,000 samples. RESULTS: EC(50) values of the positive control compounds (beta-alanine for MrgD receptor and dynorphin A for MrgA1 receptor) determined by the calcium mobilization assay were consistent with those reported in the literature, and the Z' factors were 0.65 and 0.50 for MrgD and MrgA1 receptor assay, respectively. About 31 compounds for the MrgD receptor and 48 compounds for the MrgA1 receptor showing > or =20% of the maximal agonist activities found in the controls were initially identified as hits. Secondary screening confirmed that 2 compounds for each receptor possessed specific agonist activities. Intracellular cAMP level measurements indicated that the 2 confirmed hits displayed the functionality of the MrgD receptor agonists. CONCLUSION: A series of validation studies demonstrated that the homogeneous calcium mobilization assay developed was highly efficient, amenable to automation and a robust tool to screen potential MrgD and MrgA1 receptor agonists. Its application may be expanded to other G-protein coupled receptors that mobilize calcium influx upon activation.     

Development of the high throughput screening assay for identification of agonists of an orphan nuclear receptor

Retina-specific nuclear receptor (RNR), also known as PNR and NR2E3, is an orphan nuclear receptor expressed exclusively in photoreceptor cells of the retina. Here we describe homogeneous cell-based resonance energy transfer assay for identification of RNR agonists using beta-lactamase as the reporter gene. Bacterial beta-lactamase reporter construct containing GAL4 response elements was randomly integrated into the genome with subsequent selection of responsive cell pools by fluorescence-activated cell sorting. Chimeric RNR (RNR hinge and ligand-binding domains fused to GAL4 DNA-binding domain) was stably transfected into mammalian Flp-In Chinese hamster ovary cells using Flp-mediated recombination into a single pre-integrated Flp recombination target site. Since no RNR ligand could be used as a control for monitoring the development of the RNR assay, we developed a parallel cell line with the functionally related well-characterized thyroid hormone nuclear receptor. This parallel thyroid hormone nuclear receptor system was used as a "guide" in optimizing the RNR assay for ultra-high-throughput screening in 3,456-well nanoplate format. The assay was successfully used to screen a large compound collection for RNR agonists. In this study we demonstrated the feasibility of developing and optimization of the high-throughput screening-compatible assay for the orphan nuclear receptor in the absence of its cognitive ligand.     

化合物药物活性的高通量筛选

介绍高通量药物筛选系统的组成及其相关技术。结合国家药物筛选中心的工作,详细介绍了化合物药物活性的高通量筛选的４ 个组成部分及其在药物发现过程中的作用。高通量药物筛选系统是一个涉及多个学科的、以分子生物学、新型检测技术技术为基础的新型药物发现系统。高通量药物筛选系统的顺利开展可以加速我国的新药研究     

糖原磷酸化酶抑制剂高通量筛选模型的建立*

目的:建立糖原磷酸化酶(GPa)抑制剂的体外高通量筛选模型。方法:用梯度离心方法提取大鼠肝脏GPa,以葡萄糖-1-磷酸作为底物,通过测定反应中磷酸根的释放量,间接反映肝脏GPa的活性。通过对反应体系的优化,调整反应条件,建立96孔微孔板的高通量筛选模型,用咖啡因对此模型进行验证,并评价高通量技术参数[Z′-因子(Z-′factor),信号本底比(signal to background,S/B),信噪比(signal to noise,S/N)]。用此模型对5 000个样品(包括合成化合物、天然提取物)组成的随机库进行体外筛选,考察这些样品对GPa的抑制作用。结果:确定反应体系条件是:反应温度25℃,反应时间30 m in,底物浓度0.5 mmol.L-1,大鼠肝脏GPa的用量为250 ng。用此条件测定咖啡因对GPa的抑制曲线,计算其半数抑制浓度(IC50)为(285.3±39.6)μmol.L-1,与文献报道(IC50=240μmol.L-1)基本一致;本模型技术参数Z′-因子=0.79,S/B=0.45,S/N=11.32,表明此模型可以用于高通量筛选。应用此模型筛选得到有活性的化合物9个,其IC50在3.56~45.75μmol.L-1。结论:建立的体外GPa抑制剂高通量筛选模型具有快速、微量、准确的特点,可以作为研究降糖药的工具。     

谷胱甘肽转移酶抑制剂的高通量筛选

谷胱甘肽转移酶(glutathione Stransferase,GST)是一组具有多种生理功能的同工酶家族,广泛分布于动植物体内,作为机体的II相解毒酶,参与机体的解毒作用[1].研究表明,GST的酶活性水平与肿瘤的耐药性密切相关[2～4].因此,GST可能是治疗耐药肿瘤的潜在药物作用靶点. 目前已知的GST抑制剂大多因毒性较大,限制了临床应用.研究发现,一些动植物体内含有对GST有抑制剂作用的成分[5～8].为了广泛寻找GST特异性抑制剂,本研究旨在建立一种快速、高效、稳定、经济的高通量筛选方法,以GST为靶点,通过高通量筛选技术,对自然界广泛存在着的抑制GST活性的物质进行筛选,以期为开发安全有效的、提高耐药肿瘤临床化疗敏感性的药物提供新的技术方法.     

A high throughput screening system for predicting chemically-induced reproductive organ deformities

There is a great need for alternative testing methods for reproductive toxicants that are practical, fast, cost-effective and easy to interpret. Previously we followed a pragmatic approach using readily available tests, which was successful in predicting reproductive toxicity of chemicals [13]. This initial battery still contained apical tests and is fairly complex and low in its throughput. The current study aimed to simplify this screening battery using a mechanistic approach and a panel of high throughput CALUX reporter gene assays. A mechanistic approach was taken to validate this high throughput test battery. To this end it was challenged with two preselected sets of chemicals addressing two major apical effect classes relevant in reproductive toxicity. We found selectivity in this battery in that 82% of the compounds inducing reproductive organ deformities were predicted correctly, while for compounds inducing neural tube defects this was the case in 47% only. This is consistent with the mechanisms of toxicity covered in the battery. The most informative assays in the battery were ERalpha CALUX to measure estrogenicity and the AR-anti CALUX assay to measure androgen receptor antagonism.