Drug Screening Technologies Research Articles

Heteromers of μ‐δ opioid receptors: new pharmacology and novel therapeutic possibilities

Several studies suggest that heteromerization between μ (MOP) and δ (DOP) opioid receptors modulates the signalling properties of the individual receptors. For example, whereas activation of MOP receptors by an agonist induces G protein-mediated signalling, the same agonist induces β-arrestin-mediated signalling in the context of the MOP-DOP receptor heteromer. Moreover, heteromer-mediated signalling is allosterically modulated by a combination of MOP and DOP receptor ligands. This has implications in analgesia given that morphine-induced antinociception can be potentiated by DOP receptor ligands. Recently reagents selectively targeting the MOP-DOP receptor heteromer such as bivalent ligands, antibodies or membrane permeable peptides have been generated; these reagents are enabling studies to elucidate the contribution of endogenously expressed heteromers to analgesia as well as to the development of side-effects associated with chronic opioid use. Recent advances in drug screening technology have led to the identification of a MOP-DOP receptor heteromer-biased agonist that activates both G protein-mediated and β-arrestin-mediated signalling. Moreover, this heteromer-biased agonist exhibits potent antinociceptive activity but with reduced side-effects, suggesting that ligands targeting the MOP-DOP receptor heteromer form a basis for the development of novel therapeutics for the treatment of pain. In this review, we summarize findings regarding the biological and functional characteristics of the MOP-DOP receptor heteromer and the in vitro and in vivo properties of heteromer-selective ligands. This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.

Contributions from emerging transcriptomics technologies and computational strategies for drug discovery

Drug discovery involves various steps and is a long process being even more demanding for complex diseases such as cancer. Tumors are ensembles of subpopulations with different mutations, require very specific and effective strategies. Conventional drug screening technologies may not be adequate and efficient anymore. Drug repositioning is a useful strategy to identify new uses for previously failed drugs. High throughput and deep sequencing technologies provide valuable support by yielding enormous amounts of "-omics" data and contribute to understanding the molecular mechanisms responsible for drug action. Computational methods coupled with systems biology represent a promising step to interpret pharmacogenomic data and establish strong connections with drug discovery. Genomic variations have been found to be linked with differential drug response among individuals. Large genome wide association studies are necessary to identify reliable connections between genomic variations and drug response since personalized medicine has been accepted as an important phenomenon in the drug discovery and development process post approval.

Highly Sensitive Quantitative Imaging for Monitoring Single Cancer Cell Growth Kinetics and Drug Response

The detection and treatment of cancer has advanced significantly in the past several decades, with important improvements in our understanding of the fundamental molecular and genetic basis of the disease. Despite these advancements, drug-screening methodologies have remained essentially unchanged since the introduction of the in vitro human cell line screen in 1990. Although the existing methods provide information on the overall effects of compounds on cell viability, they are restricted by bulk measurements, large sample sizes, and lack capability to measure proliferation kinetics at the individual cell level. To truly understand the nature of cancer cell proliferation and to develop personalized adjuvant therapies, there is a need for new methodologies that provide quantitative information to monitor the effect of drugs on cell growth as well as morphological and phenotypic changes at the single cell level. Here we show that a quantitative phase imaging modality known as spatial light interference microscopy (SLIM) addresses these needs and provides additional advantages over existing proliferation assays. We demonstrate these capabilities through measurements on the effects of the hormone estradiol and the antiestrogen ICI182,780 (Faslodex) on the growth of MCF-7 breast cancer cells. Along with providing information on changes in the overall growth, SLIM provides additional biologically relevant information. For example, we find that exposure to estradiol results in rapidly growing cells with lower dry mass than the control population. Subsequently blocking the estrogen receptor with ICI results in slower growing cells, with lower dry masses than the control. This ability to measure changes in growth kinetics in response to environmental conditions provides new insight on growth regulation mechanisms. Our results establish the capabilities of SLIM as an advanced drug screening technology that provides information on changes in proliferation kinetics at the cellular level with greater sensitivity than any existing method.

Business analysis and market potential of drug screening technology for preventive and personalized therapy

We have taken the business analysis to evaluate US market potential of new technology for preventive and personalized therapy (PT) of human diseases – Method for screening drug preparations (Method) [1] and it impact on the public health. Six sexually transmitted diseases (HCV, HBV, HPV, HSV, HIV and genital chlamidiosis), influenza, other acute respiratory diseases (ARD) and cancer [2] were used for the analysis. PT can allow to save up to $17.5 – 19.25 billion for Medicare/Medicaid for US hepatitis C market. The cost of the treatment of one patient with melanoma stage II - III can decrease 3-fold (saved $3,950 per patient per year) while the efficacy have to increase 2 – 3-fold. At cancer forms with no effective and safe adjuvant therapy PT can decrease the rate of metastatic stage which requires high-cost cytostatic therapy. PT with antiretrovirals and cytostatics can allow reduction of high expense of hospital stay for the patients with AIDS and metastatic cancer due to higher efficacy. PT will decrease the rate of non-effective treatment and number of relapses of HPV-infection, genital herpes and urogenital chlamidyosis as well as the number of new cases due to less spreading via sexual contacts. Preventive PT of HPV-infection with unfavorable HPV types will lead to less number of cases with cervical neoplasia. Preventive PT in risk group of 1% cases of influenza (950,000 cases) will give the ability for the insurance companies to save money for the treatment of 2.8 – 3.4 mln episodes of influenza and ARD. At the same time the number of restricted-activity days will decrease for 10 – 12 mln, bed days – for 5 – 7 mln and work-loss days due to flu and other ARD – for 2 – 2.5 mln. The Market potential data of Method are summarized in the table below. Table 1. US estimated market potential of the Method for Screening Drug Preparations Other perspective directions of PT using proposed Method: atherosclerosis, diabetes, endometriosis, chronic fatigue syndrome; CMV-, EBV-, HelicobacterPylori infections, sepsis and tuberculosis.

The promises of stem cells: stem cell therapy for movement disorders

Despite the multitude of intensive research, the exact pathophysiological mechanisms underlying movement disorders including Parkinson's disease, multiple system atrophy and Huntington's disease remain more or less elusive. Treatments to halt these disease progressions are currently unavailable. With the recent induced pluripotent stem cells breakthrough and accomplishment, stem cell research, as the vast majority of scientists agree, holds great promise for relieving and treating debilitating movement disorders. As stem cells are the precursors of all cells in the human body, an understanding of the molecular mechanisms that govern how they develop and work would provide us many fundamental insights into human biology of health and disease. Moreover, stem-cell-derived neurons may be a renewable source of replacement cells for damaged neurons in movement disorders. While stem cells show potential for regenerative medicine, their use as tools for research and drug testing is thought to have more immediate impact. The use of stem-cell-based drug screening technology could be a big boost in drug discovery for these movement disorders. Particular attention should also be given to the involvement of neural stem cells in adult neurogenesis so as to encourage its development as a therapeutic option.

Report on the 10th Anniversary of International Drug Discovery Science and Technology Conference, 8 – 10 November 2012, Nanjing, China

The 10th Anniversary of International Drug Discovery Science and Technology (IDDST) Conference was held in Nanjing, China from 8 to 10 November 2012. The conference ran in parallel with the 2nd Annual Symposium of Drug Delivery Systems. Over 400 delegates from both conferences came together for the Opening Ceremony and Keynote Addresses but otherwise pursued separate paths in the huge facilities of the Nanjing International Expo Centre. The IDDST was arranged into 19 separate Chapters covering drug discovery biology, target validation, chemistry, rational drug design, pharmacology and toxicology, drug screening technology, ‘omics' technologies, analytical, automation and enabling technologies, informatics, stem cells and regenerative medicine, bioprocessing, generics, biosimilars and biologicals and seven disease areas: cancer, CNS, respiratory and inflammation, autoimmune, emerging infectious, bone and orphan diseases. There were also two sessions of a ‘Bench to Bedside to Business' Program and a Chinese Scientist programme. In each period of the IDDST conference, up to seven sessions were running in parallel. This Meeting Highlight samples just a fraction of the content of this large meeting. The talks included have as a link, the use of new approaches to drug discovery. Many other excellent talks could have been highlighted and the author has necessarily had to be selective.

A Review of Traditional Japanese Medicines and their Potential Mechanism of Action

Traditional Japanese herbal, or Kampo medicine was developed and modified from Chinese herbal medicine. After the Japanese government approved Kampo for clinical use, much attention has been paid to establishing scientific evidence for the effectiveness of these medicines. Recent progress has been made in elucidating the mechanisms of action of some types of Kampo medicine, including rikkunshito (RKT), daikenchuto, and yokukansan. In this review, we focused on identifying the target molecules and the active ingredients of RKT. Thus far, many target molecules have been implicated in the mechanism of action of Kampo medicines, such as ion channels, enzymes, and receptors. In particular, G protein-coupled receptors are attractive candidates for explaining herbal medicine activity. This is particularly true of RKT, which is composed of 8 independent, crude drug extracts. Recent reports have shown that RKT elicits its effects through dual action to the G protein-coupled receptors: inhibition of serotonergic 5-HT2C and 5-HT2B receptors and activation of ghrelin receptors via specific ingredients of RKT. In addition, we suggest that the identification of the effective ingredients from Kampo medicines could contribute to the discovery and development of new drugs by means of modern high-throughput drug screening technology.

Screening of active ingredients contained in natural products based on micro-fluidic chip technology

With the constant development of the drug screening technology, new screening methods and techniques have came to the fore, driving drug screening to grow rapidly and efficiently with a high throughput. Characterized by micro-scale analysis, high throughput, inheritability and good biocompatibility, the micro-fluidic analytical technology provides a new method and technical platform for screening active ingredients from natural products. This essay introduces multiple methods used for screening active ingredients from natural products and focuses on the micro-fluidic chip screening technology combined with cell culture and its characteristics, the composition of the platform of the micro-fluidic chip screening technology and its application in screening active ingredients from natural products.

The Insecticide Synergist Piperonyl Butoxide Inhibits Hedgehog Signaling: Assessing Chemical Risks

The spread of chemicals, including insecticides, into the environment often raises public health concerns, as exemplified by a recent epidemiologic study associating in utero piperonyl butoxide (PBO) exposure with delayed mental development. The insecticide synergist PBO is listed among the top 10 chemicals detected in indoor dust; a systematic assessment of risks from PBO exposure, as for many toxicants unfortunately, may be underdeveloped when important biological targets that can cause toxicity are unknown. Hedgehog/Smoothened signaling is critical in neurological development. This study was designed to use novel high-throughput in vitro drug screening technology to identify modulators of Hedgehog signaling in environmental chemicals to assist the assessment of their potential risks. A directed library of 1408 environmental toxicants was screened for Hedgehog/Smoothened antagonist activity using a high-content assay that evaluated the interaction between Smoothened and βarrestin2 green fluorescent protein. PBO was identified as a Hedgehog/Smoothened antagonist capable of inhibiting Hedgehog signaling. We found that PBO bound Smoothened and blocked Smoothened overexpression-induced Gli-luciferase reporter activity but had no effect on Gli-1 downstream transcriptional factor-induced Gli activity. PBO inhibited Sonic Hedgehog ligand-induced Gli signaling and mouse cerebellar granular precursor cell proliferation. Moreover, PBO disrupted zebrafish development. Our findings demonstrate the value of high-throughput target-based screening strategies that can successfully evaluate large numbers of environmental toxicants and identify key targets and unknown biological activity that is helpful in properly assessing potential risks.

Tunable detection sensitivity of opiates in urine via a label-free porous silicon competitive inhibition immunosensor.

Currently, there is need for laboratory-based high-throughput and reliable point-of-care drug screening methodologies. We demonstrate here a chip-based label-free porous silicon (PSi) photonic sensor for detecting opiates in urine. This technique provides a cost-effective alternative to conventional labeled drug screening immunoassays with potential for translation to multiplexed analysis. Important effects of surface chemistry and competitive binding assay protocol on the sensitivity of opiate detection are revealed. Capability to tune sensitivity and detection range over approximately 3 orders of magnitude (18.0 nM to 10.8 muM) was achieved by varying the applied urine specimen volume (100-5 muL), which results in systematic shifts in the competitive binding response curve. A detection range (0.36-4.02 muM) of morphine in urine (15 muL) was designed to span the current positive cutoff value (1.05 muM morphine) in medical opiate urine screening. Desirable high cross-reactivity to oxycodone, in addition to other common opiates, morphine, morphine-3-glucuronide, 6-acetyl morphine, demonstrates an advantage over current commercial screening assays, while low interference with cocaine metabolite was maintained. This study uniquely displays PSi sensor technology as an inexpensive, rapid, and reliable drug screening technology. Furthermore, the versatile surface chemistry developed can be implemented on a range of solid-supported sensors to conduct competitive inhibition assays.

Abstract ED02-04: Identifying targets for breast and ovarian cancer prevention

Abstract ED02-04: Identifying targets for breast and ovarian cancer prevention

Progress in the Development of Nonpeptidomimetic BACE 1 Inhibitors for Alzheimers Disease

It is believed that the production and accumulation of beta-amyloid (Abeta) peptide is a critical step to the pathogenesis of Alzheimer's disease (AD). BACE 1 (beta-site APP-cleaving enzyme 1 or beta-secretase), the key enzyme required for generating Abeta from the beta-amyloid precursor protein (APP), is regarded as an ideal target for AD therapeutic drug design. Due to low oral bioavailability, metabolic instability and poor ability to penetrate the central nervous system (CNS) of the existing peptidomimetic inhibitors, researchers have paid more attention to the development of nonpeptidomimetic inhibitors in recent years. A number of drug screening approaches and technologies have been used to identify novel nonpeptidomimetic BACE 1 inhibitors. This review mainly focuses on the recent developments in structure-based design and synthesis of the nonpeptidomimetic BACE 1 inhibitors.

Indexing TNF-αgene expression using a gene-targeted reporter cell line

BackgroundCurrent cell-based drug screening technologies utilize randomly integrated reporter genes to index transcriptional activity of an endogenous gene of interest. In this context, reporter expression is controlled by known genetic elements that may only partially capture gene regulation and by unknown features of chromatin specific to the integration site. As an alternative technology, we applied highly efficient gene-targeting with recombinant adeno-associated virus to precisely integrate a luciferase reporter gene into exon 1 of the HeLa cell tumor necrosis factor-alpha (TNF-α) gene. Drugs known to induce TNF-α expression were then used to compare the authenticity of gene-targeted and randomly integrated transcriptional reporters.ResultsTNF-α-targeted reporter activity reflected endogenous TNF-α mRNA expression, whereas randomly integrated TNF-α reporter lines gave variable expression in response to transcriptional and epigenetic regulators. 5,6-Dimethylxanthenone-4-acetic acid (DMXAA), currently used in cancer clinical trials to induce TNF-α gene transcription, was only effective at inducing reporter expression from TNF-α gene-targeted cells.ConclusionWe conclude that gene-targeted reporter cell lines provide predictive indexing of gene transcription for drug discovery.

Small Molecule Inhibitors of the p53-MDM2

Recent researches have discovered that MDM2 (murine double minute 2, or HDM2 for the human congener) protein is the main negative regulator of p53, which is an attractive therapeutic target in oncology because its tumor-suppressor activity which can be stimulated to eradicate tumor cells. Inhibiting the p53-MDM2 interaction is a promising approach for activating p53, because this association is well characterized at the structural and biological levels. A number of drug screening approaches and technologies have been used to identity novel inhibitors of the p53-MDM2 interaction. This review will detail the development history of MDM2 protein and the p53-MDM2 interaction, the major classes of novel small-molecular p53-MDM2 binding inhibitors, key medicinal action with the protein-protein interaction and in vitro or in vivo biological activities.

Making Singapore a Research Hub

As a science policy analyst who worked in Singapore for several years, I witnessed the Singaporean government's ambitions to turn the city-state into a world-class hub of biomedical research, ranging from basic research to manufacturing (“An Asian tiger's bold experiment,” D. Normile, News Focus, 6 Apr., p. [38][1]). In addition to the skepticism expressed in the article by Lee Wei Ling, one of Singapore's top biomedical scientists, about the dependence of the nation on the international talent pool for leaders of its biotech effort, Singapore faces other challenges. First, biotech research is uncertain and it can take many years to achieve a breakthrough. Furthermore, advances in understanding pathways operating in human beings are not automatically translatable into commercialized, profitable products. It is not unusual for a pharmaceutical company to spend 10 years and billions of dollars developing a new drug. Although improvements in drug-screening technologies, automation of the screening process, and advances in genomics may change the “hit-or-miss” drug discovery process and shorten the development cycle, pharmaceutical companies will continue to see high rates of failure and enormous development costs. It remains to be seen whether Singaporeans are ready to embrace uncertainties and tolerate failures. Second, the talent challenge may not be easily resolved. Singapore has started using a government fellowship program to send students abroad. But it will take at least 10 years—the normal time for a doctoral degree plus postdoctoral research experience—for them to become independent researchers and longer to become internationally renowned. Also, in contrast to the United States, where the biotech industry has benefited from strong entrepreneurial efforts by academic scientists, their counterparts in Singapore, as civil servants, operate in a highly rigid, hierarchical system where moves between academia and industry are rare. Also, Singaporean youngsters may not be willing to stick to tedious benchwork that may or may not lead to financial rewards. Finally, research in Singapore profited from the ethical debates that mired stem cell and cloning research in the United States. Less restrictive rules may have been an inducement to some foreign biotech companies to set up operations in Singapore. Of course, that does not mean Singapore has no regulatory framework to review research and enforce any recommended ethical code. But Singapore's advantage may not last if the research environment becomes more open in other countries. More importantly, there should be better opportunities for civil society in Singapore to debate the issues related to biotech research. Citizens have the right to know much more about the risks and benefits associated with the biomedical sciences conducted in Singapore than they do now. Public understanding is at least as important as deep pockets and a deep talent pool. [1]: /lookup/doi/10.1126/science.316.5821.38

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New Approaches in Drug Testings: A Review of Hair Analysis

This article reviews the development of hair analysis as a drug-screening technology. It compares the advantages and disadvantages of drug screens that employ urinalysis and hair analysis technologies. It reviews the various controversies that have attended the development and implementation of hair analysis. It discusses the role of ideological, sociological, and political factors in the evolution of the technique. Finally, it reviews professional and governmental responses to the technology and recommends future courses of research to resolve the outstanding disagreements.