ABSTRACT
This pilot randomized controlled trial (RCT) examined preliminary effects of an 8-week videoconferencing acceptance and commitment therapy (ACT) program supplemented with psychoeducation materials on distressed family caregivers of persons living with dementia (PLWD) compared to the control group provided with psychoeducation materials only. Nineteen family caregivers of PLWD in the USA were randomly assigned to the ACT group or the control group. Data was collected at pretest, posttest, and 1-month follow-up (F/U). Compared to the control group, the ACT group showed a significantly larger reduction in grief at posttest, with a medium effect size. Small effects of ACT were found in anxiety, psychological quality of life, and engagement in meaningful activities at posttest and grief, engagement in meaningful activities, and psychological flexibility at F/U compared to the control group. These promising findings warrant a full-scale RCT with adequate power to measure the efficacy of videoconferencing ACT for caregivers of PLWD.
Subject(s)
Acceptance and Commitment Therapy , Dementia , Humans , Caregivers/psychology , Feasibility Studies , Pilot Projects , Videoconferencing , Quality of Life , Dementia/therapyABSTRACT
PURPOSE: This study examined effects of coach-guided videoconferencing acceptance and commitment therapy (ACT) accompanied by psychoeducation on distressed individuals with spinal cord injury (SCI) and explored participants' experiences in the intervention. MATERIALS AND METHODS: Ten people with SCI participated in 8 individual videoconferencing sessions delivered by trained coaches. Data using self-reported questionnaires and individual interviews was collected at pretest and posttest and analyzing using Wilcoxon signed-rank tests and interpretative phenomenological analysis (ClinicalTrials.gov ID: NCT04670406). RESULTS: Statistically significant improvements were found in depression, anxiety, stress, grief, engagement in meaningful activities, and self-compassion with medium to large effect sizes. There was no significant change in quality of life, resilience, and ACT processes. Participants gained a new way of thinking by: being aware of thoughts and emotions; exploring perceptions of others; and focusing on the present. Also, the intervention equipped participants to deal with challenges by: improving coping with SCI-related conditions; practicing self-compassion, acceptance, and meditation; and acquiring skills of value-based decision making and committed action. CONCLUSIONS: Findings contribute to the limited evidence as the first study that measured effects of videoconferencing ACT on people with SCI. Future randomized controlled trials are needed to measure efficacy of internet-delivered ACT for people with SCI.IMPLICATIONS FOR REHABILITATIONGuided videoconferencing ACT may reduce depressive symptoms, anxiety, stress, and grief and increase engagement in meaningful activities and self-compassion in people with SCI.Professionals may consider ACT as a supportive or adjunct service for people with SCI who experience psychological distress.
Subject(s)
Acceptance and Commitment Therapy , Spinal Cord Injuries , Humans , Anxiety/therapy , Quality of Life/psychology , Spinal Cord Injuries/psychology , VideoconferencingABSTRACT
OBJECTIVES: This study examined the effects of a guided online acceptance and commitment therapy (ACT) intervention on distressed family caregivers of persons living with dementia and explored the experiences of these caregivers in the ACT intervention. METHODS: Seven family caregivers experiencing psychological distress individually participated in 10 ACT videoconference sessions guided by a trained coach. Quantitative data, such as psychological distress, burden, and ACT processes, were collected at pretest and posttest and analyzed using the Wilcoxon signed-rank test. Individual interviews were conducted at posttest and analyzed using interpretative phenomenological analysis. RESULTS: Statistically significant reductions were found in depressive symptoms, anxiety, stress, and burden (p < .05) with medium effect sizes. ACT sessions helped caregivers gain renewed strength by: being equipped with resources to use under distress throughout the caregiving journey; being more self-compassionate and taking care of one's self; and being more patient with relatives with dementia. CONCLUSIONS: Findings contribute to the limited evidence in guided online ACT for caregivers of persons living with dementia. Further studies with a larger sample size are needed to evaluate the efficacy of guided online ACT. CLINICAL IMPLICATIONS: Guided online ACT may reduce depressive symptoms, anxiety, stress, and burden of family caregivers of persons living with dementia.
Subject(s)
Acceptance and Commitment Therapy , Dementia , Anxiety/psychology , Anxiety/therapy , Caregivers/psychology , Dementia/psychology , HumansABSTRACT
Acceptance and commitment therapy is an emerging evidenced-based practice, but no systematic review regarding the effects of ACT on family caregivers has been conducted. This article examined the effects of ACT on family caregivers by conducting meta-analysis with a random effects model. Twenty-four articles were identified from four electronic databases searched up to 30 March 2020. Meta-analyses found moderate effects of ACT on depressive symptoms and quality of life, small effects on anxiety, and small to moderate effects on stress. Further ACT studies should be conducted to measure effects on different outcomes for various family caregiver populations.
Subject(s)
Acceptance and Commitment Therapy , Caregivers , Anxiety , Anxiety Disorders , Humans , Quality of LifeABSTRACT
Despite the usefulness of high-throughput screening (HTS) in drug discovery, for some systems, low assay throughput or high screening cost can prohibit the screening of large numbers of compounds. In such cases, iterative cycles of screening involving active learning (AL) are employed, creating the need for smaller "informer sets" that can be routinely screened to build predictive models for selecting compounds from the screening collection for follow-up screens. Here, we present a data-driven derivation of an informer compound set with improved predictivity of active compounds in HTS, and we validate its benefit over randomly selected training sets on 46 PubChem assays comprising at least 300,000 compounds and covering a wide range of assay biology. The informer compound set showed improvement in BEDROC(α = 100), PRAUC, and ROCAUC values averaged over all assays of 0.024, 0.014, and 0.016, respectively, compared to randomly selected training sets, all with paired t-test p-values <10(-15). A per-assay assessment showed that the BEDROC(α = 100), which is of particular relevance for early retrieval of actives, improved for 38 out of 46 assays, increasing the success rate of smaller follow-up screens. Overall, we showed that an informer set derived from historical HTS activity data can be employed for routine small-scale exploratory screening in an assay-agnostic fashion. This approach led to a consistent improvement in hit rates in follow-up screens without compromising scaffold retrieval. The informer set is adjustable in size depending on the number of compounds one intends to screen, as performance gains are realized for sets with more than 3,000 compounds, and this set is therefore applicable to a variety of situations. Finally, our results indicate that random sampling may not adequately cover descriptor space, drawing attention to the importance of the composition of the training set for predicting actives.
Subject(s)
Drug Evaluation, Preclinical/methods , High-Throughput Screening Assays/methods , Informatics/methods , Machine LearningABSTRACT
Discovering the unintended 'off-targets' that predict adverse drug reactions is daunting by empirical methods alone. Drugs can act on several protein targets, some of which can be unrelated by conventional molecular metrics, and hundreds of proteins have been implicated in side effects. Here we use a computational strategy to predict the activity of 656 marketed drugs on 73 unintended 'side-effect' targets. Approximately half of the predictions were confirmed, either from proprietary databases unknown to the method or by new experimental assays. Affinities for these new off-targets ranged from 1 nM to 30 µM. To explore relevance, we developed an association metric to prioritize those new off-targets that explained side effects better than any known target of a given drug, creating a drug-target-adverse drug reaction network. Among these new associations was the prediction that the abdominal pain side effect of the synthetic oestrogen chlorotrianisene was mediated through its newly discovered inhibition of the enzyme cyclooxygenase-1. The clinical relevance of this inhibition was borne out in whole human blood platelet aggregation assays. This approach may have wide application to de-risking toxicological liabilities in drug discovery.
Subject(s)
Drug Evaluation, Preclinical/methods , Drug-Related Side Effects and Adverse Reactions , Toxicity Tests/methods , Blood Platelets/drug effects , Chlorotrianisene/adverse effects , Chlorotrianisene/chemistry , Chlorotrianisene/pharmacology , Cyclooxygenase 1/metabolism , Cyclooxygenase Inhibitors/adverse effects , Cyclooxygenase Inhibitors/pharmacology , Databases, Factual , Estrogens, Non-Steroidal/adverse effects , Estrogens, Non-Steroidal/pharmacology , Forecasting , Humans , Models, Biological , Molecular Targeted Therapy/adverse effects , Platelet Aggregation/drug effects , Reproducibility of Results , Substrate SpecificityABSTRACT
Since the advent of high-throughput screening (HTS), there has been an urgent need for methods that facilitate the interrogation of large-scale chemical biology data to build a mode of action (MoA) hypothesis. This can be done either prior to the HTS by subset design of compounds with known MoA or post HTS by data annotation and mining. To enable this process, we developed a tool that compares compounds solely on the basis of their bioactivity: the chemical biological descriptor "high-throughput screening fingerprint" (HTS-FP). In the current embodiment, data are aggregated from 195 biochemical and cell-based assays developed at Novartis and can be used to identify bioactivity relationships among the in-house collection comprising ~1.5 million compounds. We demonstrate the value of the HTS-FP for virtual screening and in particular scaffold hopping. HTS-FP outperforms state of the art methods in several aspects, retrieving bioactive compounds with remarkable chemical dissimilarity to a probe structure. We also apply HTS-FP for the design of screening subsets in HTS. Using retrospective data, we show that a biodiverse selection of plates performs significantly better than a chemically diverse selection of plates, both in terms of number of hits and diversity of chemotypes retrieved. This is also true in the case of hit expansion predictions using HTS-FP similarity. Sets of compounds clustered with HTS-FP are biologically meaningful, in the sense that these clusters enrich for genes and gene ontology (GO) terms, showing that compounds that are bioactively similar also tend to target proteins that operate together in the cell. HTS-FP are valuable not only because of their predictive power but mainly because they relate compounds solely on the basis of bioactivity, harnessing the accumulated knowledge of a high-throughput screening facility toward the understanding of how compounds interact with the proteome.
Subject(s)
Chemistry, Pharmaceutical/methods , High-Throughput Screening Assays/methods , Animals , Biochemistry/methods , Cluster Analysis , Computational Biology/methods , Drug Design , Drug Evaluation, Preclinical/methods , Humans , Ligands , Models, Chemical , Models, Molecular , Molecular Conformation , Quantitative Structure-Activity RelationshipABSTRACT
INTRODUCTION: The goal of early predictive safety assessment (PSA) is to keep compounds with detectable liabilities from progressing further in the pipeline. Such compounds jeopardize the core of pharmaceutical research and development and limit the timely delivery of innovative therapeutics to the patient. Computational methods are increasingly used to help understand observed data, generate new testable hypotheses of relevance to safety pharmacology, and supplement and replace costly and time-consuming experimental procedures. AREAS COVERED: The authors survey methods operating on different scales of both physical extension and complexity. After discussing methods used to predict liabilities associated with structures of individual compounds, the article reviews the use of adverse event data and safety profiling panels. Finally, the authors examine the complexities of toxicology data from animal experiments and how these data can be mined. EXPERT OPINION: A significant obstacle for data-driven safety assessment is the absence of integrated data sets due to a lack of sharing of data and of using standard ontologies for data relevant to safety assessment. Informed decisions to derive focused sets of compounds can help to avoid compound liabilities in screening campaigns, and improved hit assessment of such campaigns can benefit the early termination of undesirable compounds.
Subject(s)
Computational Biology/methods , Drug Evaluation, Preclinical/methods , Drug-Related Side Effects and Adverse Reactions , Pharmaceutical Preparations/metabolism , Animals , Chemical Phenomena , Computer Simulation , Endpoint Determination , HumansABSTRACT
Given the tremendous growth of bioactivity databases, the use of computational tools to predict protein targets of small molecules has been gaining importance in recent years. Applications span a wide range, from the 'designed polypharmacology' of compounds to mode-of-action analysis. In this review, we firstly survey databases that can be used for ligand-based target prediction and which have grown tremendously in size in the past. We furthermore outline methods for target prediction that exist, both based on the knowledge of bioactivities from the ligand side and methods that can be applied in situations when a protein structure is known. Applications of successful in silico target identification attempts are discussed in detail, which were based partly or in whole on computational target predictions in the first instance. This includes the authors' own experience using target prediction tools, in this case considering phenotypic antibacterial screens and the analysis of high-throughput screening data. Finally, we will conclude with the prospective application of databases to not only predict, retrospectively, the protein targets of a small molecule, but also how to design ligands with desired polypharmacology in a prospective manner.
Subject(s)
Computer Simulation , Databases, Factual , Drug Design , Drug Evaluation, Preclinical/methods , Animals , HumansABSTRACT
Chemogenomics knowledge-based drug discovery approaches aim to extract the knowledge gained from one target and to apply it for the discovery of ligands and hopefully drugs of a new target which is related to the parent target by homology or conserved molecular recognition. Herein, we demonstrate the potential of knowledge-based virtual screening by applying it to the MDM4-p53 protein-protein interaction where the MDM2-p53 protein-protein interaction constitutes the parent reference system; both systems are potentially relevant to cancer therapy. We show that a combination of virtual screening methods, including homology based similarity searching, QSAR (Quantitative Structure-Activity Relationship) methods, HTD (High Throughput Docking), and UNITY pharmacophore searching provide a successful approach to the discovery of inhibitors. The virtual screening hit list is of the magnitude of 50,000 compounds picked from the corporate compound library of approximately 1.2 million compounds. Emphasis is placed on the facts that such campaigns are only feasible because of the now existing HTCP (High throughput Cherry-Picking) automation systems in combination with robust MTS (Medium Throughput Screening) fluorescence-based assays. Given that the MDM2-p53 system constitutes the reference system, it is not surprising that significantly more and stronger hits are found for this interaction compared to the MDM4-p53 system. Novel, selective and dual hits are discovered for both systems. A hit rate analysis will be provided compared to the full HTS (High-throughput Screening).
Subject(s)
Drug Evaluation, Preclinical/statistics & numerical data , Knowledge Bases , Nuclear Proteins/chemistry , Protein Interaction Mapping/statistics & numerical data , Proto-Oncogene Proteins/chemistry , Tumor Suppressor Protein p53/chemistry , Cell Cycle Proteins , Decision Trees , Drug Discovery/statistics & numerical data , High-Throughput Screening Assays/statistics & numerical data , Humans , Models, Molecular , Molecular Biology/methods , Nuclear Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-mdm2/chemistry , Proto-Oncogene Proteins c-mdm2/metabolism , Quantitative Structure-Activity Relationship , Structural Homology, Protein , Tumor Suppressor Protein p53/metabolism , User-Computer InterfaceABSTRACT
Understanding the safety of newly developed compounds is a key task in each early drug discovery project. In early stages, pharmaceutical companies address this task by using so-called preclinical safety profiling, in which compounds are screened in inexpensive large-scale assays to understand possible liabilities. This process generates a large amount of binding data on various compounds against a panel of targets - usually thousands or tens of thousands of compounds profiled against approximately 100 different targets. This data matrix is highly valuable and elicits further analysis. After briefly introducing the nature of safety profiling data, we describe several computational methods used internally at Novartis to analyze it. We showcase protocols that can be used to understand compound promiscuity on a chemical structure level and protocols to evaluate the promiscuity of targets used in safety profiling. We also describe a method to quickly determine the chemical similarity of compounds active against different targets. Next, it is shown what protocols can be used to evaluate global chemical similarity of targets. The above approaches can be used either to optimize the composition of a panel of targets or to better understand certain toxicities. Finally, we will explain a simple method to elucidate hidden patterns in safety profiling data.
Subject(s)
Drug Discovery/statistics & numerical data , Drug-Related Side Effects and Adverse Reactions , Bayes Theorem , Data Interpretation, Statistical , Drug Evaluation, Preclinical/statistics & numerical data , Genomics/statistics & numerical data , Models, Statistical , Molecular Biology/statistics & numerical data , Principal Component AnalysisABSTRACT
Typically, screening collections of pharmaceutical companies contain more than a million compounds today. However, for certain high-throughput screening (HTS) campaigns, constraints posed by the assay throughput and/or the reagent costs make it impractical to screen the entire deck. Therefore, it is desirable to effectively screen subsets of the collection based on a hypothesis or a diversity selection. How to select compound subsets is a subject of ongoing debate. The authors present an approach based on extended connectivity fingerprints to carry out diversity selection on a per plate basis (instead of a per compound basis). HTS data from 35 Novartis screens spanning 5 target classes were investigated to assess the performance of this approach. The analysis shows that selecting a fingerprint-diverse subset of 250K compounds, representing 20% of the screening deck, would have achieved significantly higher hit rates for 86% of the screens. This measure also outperforms the Murcko scaffold-based plate selection described previously, where only 49% of the screens showed similar improvements. Strikingly, the 2-fold improvement in average hit rates observed for 3 of 5 target classes in the data set indicates a target bias of the plate (and thus compound) selection method. Even though the diverse subset selection lacks any target hypothesis, its application shows significantly better results for some targets-namely, G-protein-coupled receptors, proteases, and protein-protein interactions-but not for kinase and pathway screens. The synthetic origin of the compounds in the diverse subset appears to influence the screening hit rates. Natural products were the most diverse compound class, with significantly higher hit rates compared to the compounds from the traditional synthetic and combinatorial libraries. These results offer empirical guidelines for plate-based diversity selection to enhance hit rates, based on target class and the library type being screened.
Subject(s)
Combinatorial Chemistry Techniques/instrumentation , Drug Evaluation, Preclinical/methods , Pharmaceutical Preparations/analysis , Pharmaceutical Preparations/chemistryABSTRACT
We present a workflow that leverages data from chemogenomics based target predictions with Systems Biology databases to better understand off-target related toxicities. By analyzing a set of compounds that share a common toxic phenotype and by comparing the pathways they affect with pathways modulated by nontoxic compounds we are able to establish links between pathways and particular adverse effects. We further link these predictive results with literature data in order to explain why a certain pathway is predicted. Specifically, relevant pathways are elucidated for the side effects rhabdomyolysis and hypotension. Prospectively, our approach is valuable not only to better understand toxicities of novel compounds early on but also for drug repurposing exercises to find novel uses for known drugs.
Subject(s)
Drug Evaluation, Preclinical , Systems Biology , Bayes Theorem , Drug-Related Side Effects and Adverse Reactions , Humans , Hypotension/chemically induced , Rhabdomyolysis/chemically inducedABSTRACT
Different molecular descriptors capture different aspects of molecular structures, but this effect has not yet been quantified systematically on a large scale. In this work, we calculate the similarity of 37 descriptors by repeatedly selecting query compounds and ranking the rest of the database. Euclidean distances between the rank-ordering of different descriptors are calculated to determine descriptor (as opposed to compound) similarity, followed by PCA for visualization. Four broad descriptor classes are identified, which are circular fingerprints; circular fingerprints considering counts; path-based and keyed fingerprints; and pharmacophoric descriptors. Descriptor behavior is much more defined by those four classes than the particular parametrization. Using counts instead of the presence/absence of fingerprints significantly changes descriptor behavior, which is crucial for performance of topological autocorrelation vectors, but not circular fingerprints. Four-point pharmacophores (piDAPH4) surprisingly lead to much higher retrieval rates than three-point pharmacophores (28.21% vs 19.15%) but still similar rank-ordering of compounds (retrieval of similar actives). Looking into individual rankings, circular fingerprints seem more appropriate than path-based fingerprints if complex ring systems or branching patterns are present; count-based fingerprints could be more suitable in databases with a large number of repeated subunits (amide bonds, sugar rings, terpenes). Information-based selection of diverse fingerprints for consensus scoring (ECFP4/TGD fingerprints) led only to marginal improvement over single fingerprint results. While it seems to be nontrivial to exploit orthogonal descriptor behavior to improve retrieval rates in consensus virtual screening, those descriptors still each retrieve different actives which corroborates the strategy of employing diverse descriptors individually in prospective virtual screening settings.
Subject(s)
Molecular Structure , Principal Component Analysis , Databases, Factual , Drug Evaluation, Preclinical , Informatics , User-Computer InterfaceABSTRACT
We compared two algorithms for ligand-target prediction, namely, the Laplacian-modified Bayesian classifier and the Winnow algorithm. A dataset derived from the WOMBAT database, spanning 20 pharmaceutically relevant activity classes with 13 000 compounds, was used for performance assessment in 24 different experiments, each of which was assessed using a 15-fold Monte Carlo cross-validation. Compounds were described by different circular fingerprints, ECFP_4 and MOLPRINT 2D. A detailed analysis of the resulting approximately 2.4 million predictions led to very similar measures for overall accuracy for both classifiers, whereas we observed significant differences for individual activity classes. Moreover, we analyzed our data with respect to the numbers of compounds which are exclusively retrieved by either of the algorithmsbut never by the otheror by neither of them. This provided detailed information that can never be obtained by considering the overall performance statistics alone.
Subject(s)
Algorithms , Drug Discovery/statistics & numerical data , Bayes Theorem , CDC2 Protein Kinase/metabolism , Cyclic Nucleotide Phosphodiesterases, Type 5/metabolism , Cyclin B/metabolism , Databases, Factual , Drug Design , Drug Discovery/classification , Drug Discovery/methods , Drug Evaluation, Preclinical , Ligands , Monte Carlo Method , User-Computer InterfaceABSTRACT
In this work we explore the possibilities of using fragment-based screening data to prioritize compounds from a full HTS library, a method we call virtual fragment linking (VFL). The ability of VFL to identify compounds of nanomolar potency based on micromolar fragment binding data was tested on 75 target classes from the WOMBAT database and succeeded in 57 cases. Further, the method was demonstrated for seven drug targets from in-house screening programs that performed both FBS of 8800 fragments and screens of the full library. VFL captured between 28% and 67% of the hits (IC 50 < 10microM) in the top 5% of the ranked library for four of the targets (enrichment between 5-fold and 13-fold). Our findings lead us to conclude that proper coverage of chemical space by the fragment library is crucial for the VFL methodology to be successful in prioritizing HTS libraries from fragment-based screening data.
Subject(s)
Drug Evaluation, Preclinical , Database Management Systems , Molecular WeightABSTRACT
Preclinical Safety Pharmacology (PSP) attempts to anticipate adverse drug reactions (ADRs) during early phases of drug discovery by testing compounds in simple, in vitro binding assays (that is, preclinical profiling). The selection of PSP targets is based largely on circumstantial evidence of their contribution to known clinical ADRs, inferred from findings in clinical trials, animal experiments, and molecular studies going back more than forty years. In this work we explore PSP chemical space and its relevance for the prediction of adverse drug reactions. Firstly, in silico (computational) Bayesian models for 70 PSP-related targets were built, which are able to detect 93% of the ligands binding at IC(50) < or = 10 microM at an overall correct classification rate of about 94%. Secondly, employing the World Drug Index (WDI), a model for adverse drug reactions was built directly based on normalized side-effect annotations in the WDI, which does not require any underlying functional knowledge. This is, to our knowledge, the first attempt to predict adverse drug reactions across hundreds of categories from chemical structure alone. On average 90% of the adverse drug reactions observed with known, clinically used compounds were detected, an overall correct classification rate of 92%. Drugs withdrawn from the market (Rapacuronium, Suprofen) were tested in the model and their predicted ADRs align well with known ADRs. The analysis was repeated for acetylsalicylic acid and Benperidol which are still on the market. Importantly, features of the models are interpretable and back-projectable to chemical structure, raising the possibility of rationally engineering out adverse effects. By combining PSP and ADR models new hypotheses linking targets and adverse effects can be proposed and examples for the opioid mu and the muscarinic M2 receptors, as well as for cyclooxygenase-1 are presented. It is hoped that the generation of predictive models for adverse drug reactions is able to help support early SAR to accelerate drug discovery and decrease late stage attrition in drug discovery projects. In addition, models such as the ones presented here can be used for compound profiling in all development stages.
Subject(s)
Computer Simulation , Drug Delivery Systems , Drug-Related Side Effects and Adverse Reactions , Models, Chemical , Models, Molecular , Pharmaceutical Preparations/chemistry , Antipsychotic Agents/adverse effects , Antipsychotic Agents/chemistry , Antipsychotic Agents/pharmacology , Antipsychotic Agents/therapeutic use , Arrhythmias, Cardiac/chemically induced , Benperidol/adverse effects , Benperidol/chemistry , Benperidol/pharmacology , Benperidol/therapeutic use , Databases, Factual , Drug Design , Drug Evaluation, Preclinical , Ligands , Predictive Value of TestsABSTRACT
This work describes a novel semi-sequential technique for in silico enhancement of high-throughput screening (HTS) experiments now employed at Novartis. It is used in situations in which the size of the screen is limited by the readout (e.g., high-content screens) or the amount of reagents or tools (proteins or cells) available. By performing computational chemical diversity selection on a per plate basis (instead of a per compound basis), 25% of the 1,000,000-compound screening was optimized for general initial HTS. Statistical models are then generated from target-specific primary results (percentage inhibition data) to drive the cherry picking and testing from the entire collection. Using retrospective analysis of 11 HTS campaigns, the authors show that this method would have captured on average two thirds of the active compounds (IC(50) < 10 microM) and three fourths of the active Murcko scaffolds while decreasing screening expenditure by nearly 75%. This result is true for a wide variety of targets, including G-protein-coupled receptors, chemokine receptors, kinases, metalloproteinases, pathway screens, and protein-protein interactions. Unlike time-consuming "classic" sequential approaches that require multiple iterations of cherry picking, testing, and building statistical models, here individual compounds are cherry picked just once, based directly on primary screening data. Strikingly, the authors demonstrate that models built from primary data are as robust as models built from IC(50) data. This is true for all HTS campaigns analyzed, which represent a wide variety of target classes and assay types.
Subject(s)
Combinatorial Chemistry Techniques/economics , Combinatorial Chemistry Techniques/methods , Drug Evaluation, Preclinical/economics , Drug Evaluation, Preclinical/methods , Pharmaceutical Preparations/analysis , Bayes Theorem , Software , Time FactorsABSTRACT
Lead discovery in the pharmaceutical environment is largely an industrial-scale process in which it is typical to screen 1-5 million compounds in a matter of weeks using High Throughput Screening (HTS). This process is a very costly endeavor. Typically a HTS campaign of 1 million compounds will cost anywhere from $500000 to $1000000. There is consequently a great deal of pressure to maximize the return on investment by finding fast and more effective ways to screen. A panacea that has emerged over the past few years to help address this issue is in silico screening. In silico screening is now incorporated in all areas of lead discovery; from target identification and library design, to hit analysis and compound profiling. However, as lead discovery has evolved over the past few years, so has the role of in silico screening.
Subject(s)
Computational Biology , Drug Design , Drug Evaluation, Preclinical/methods , Bayes Theorem , GenomicsABSTRACT
Angiogenin (ANG) is a potent inducer of angiogenesis and an RNase A homologue whose ribonucleolytic activity is essential for its biological action. Recently, we reported the identification of small non-nucleotide inhibitors of the enzymatic activity of ANG by high-throughput screening (HTS) [Kao, R. Y. T., et al. (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 10066-10071]. Two of the inhibitors that were obtained, National Cancer Institute compound NSC-65828 [8-amino-5-(4'-hydroxybiphenyl-4-ylazo)naphthalene-2-sulfonate] and ChemBridge compound C-181431 [4,4'-dicarboxy-3,3'-bis(naphthylamido)diphenylmethanone], were judged to be suitable for further development, and one of these (NSC-65828) was shown to possess antitumor activity in mice. Here we have used computational docking as a guide for the identification of available NSC-65828 and C-181431 analogues that bind more tightly to ANG, and for the characterization of inhibitor binding modes. Numerous analogues were found to have greater avidity than the HTS compounds or any small nucleotide inhibitors; four were considered to be of interest as potential leads (K(i) = 5-25 microM). Two of these analogues bind more tightly to ANG than to RNase A, and are the first small molecules shown to exhibit this selectivity. The predicted binding orientations of the HTS compounds and the new lead inhibitors were evaluated by determining the effects of ANG active site mutations on inhibitory potency. The results with ANG variants R5A, H8A, N68A, and des(121-123) are highly consistent with the docking models. Affinity changes observed with Q12A and Q117G reveal aspects of active site function that are not apparent from the free ANG crystal structure or from the modeled complexes. These findings should prove to be useful in the design of more effective and specific ANG antagonists.