SLAS Discovery最新文献

The importance of a drug's kinetic profile and interplay of structure-kinetic activity with PK/PD has long been appreciated in drug discovery. However, technical challenges have often limited detailed kinetic characterization of compounds to the latter stages of projects. This review highlights the advances that have been made in recent years in techniques, instrumentation, and data analysis to increase the throughput of detailed kinetic and mechanistic characterization, enabling its application earlier in the drug discovery process.

We report the development of a 384-well formatted NanoBRET assay to characterize molecular glues of 14-3-3/client interactions in living cells. The seven isoforms of 14-3-3 are dimeric hub proteins with diverse roles including transcription factor regulation and signal transduction. 14-3-3 interacts with hundreds of client proteins to regulate their function and is therefore an ideal therapeutic target when client selectivity can be achieved. We have developed the NanoBRET system for three 14-3-3σ client proteins CRAF, TAZ, and estrogen receptor α (ERα), which represent three specific binding modes. We have measured stabilization of 14-3-3σ/client complexes by molecular glues with EC₅₀ values between 100 nM and 1 μM in cells, which align with the EC₅₀ values calculated by fluorescence anisotropy in vitro. Developing this NanoBRET system for the hub protein 14-3-3σ allows for a streamlined approach, bypassing multiple optimization steps in the assay development process for other 14-3-3σ clients. The NanoBRET system allows for an assessment of PPI stabilization in a more physiologically relevant, cell-based environment using full-length proteins. The method is applicable to diverse protein-protein interactions (PPIs) and offers a robust platform to explore libraries of compounds for both PPI stabilizers and inhibitors.

DNA-encoded small molecule library technology has recently emerged as a new paradigm for identifying ligands against drug targets. To date, it has been used to identify ligands against targets that are soluble or overexpressed on cell surfaces. Here, we report applying cell-based selection methods to profile surfaces of mouse C2C12 myoblasts and myotube cells in an unbiased, target agnostic manner. A panel of on-DNA compounds were identified and confirmed for cell binding selectivity. We optimized the cell selection protocol and employed a novel data analysis method to identify cell selective ligands against a panel of human B and T lymphocytes. We discuss the generality of using this workflow for DNA encoded small molecule library selection and data analysis against different cell types, and the feasibility of applying this method to profile cell surfaces for biomarker and target identification.

The Cellular Thermal Shift Assay (CETSA) enables the study of protein-ligand interactions in a cellular context. It provides valuable information on the binding affinity and specificity of both small and large molecule ligands in a relevant physiological context, hence forming a unique tool in drug discovery. Though high-throughput lab protocols exist for scaling up CETSA, subsequent data analysis and quality control remain laborious and limit experimental throughput. Here, we introduce a scalable and robust data analysis workflow which allows integration of CETSA into routine high throughput screening (HT-CETSA). This new workflow automates data analysis and incorporates quality control (QC), including outlier detection, sample and plate QC, and result triage. We describe the workflow and show its robustness against typical experimental artifacts, show scaling effects, and discuss the impact of data analysis automation by eliminating manual data processing steps.

Zika virus (ZIKV) continues to pose a significant global public health threat, with recurring regional outbreaks and potential for pandemic spread. Despite often being asymptomatic, ZIKV infections can have severe consequences, including neurological disorders and congenital abnormalities. Unfortunately, there are currently no approved vaccines or antiviral drugs for the prevention or treatment of ZIKV. One promising target for drug development is the ZIKV NS2B-NS3 protease due to its crucial role in the virus life cycle. In this study, we established a cell-based ZIKV protease inhibition assay designed for high-throughput screening (HTS). Our assay relies on the ZIKV protease's ability to cleave a cyclised firefly luciferase fused to a natural cleavage sequence between NS2B and NS3 protease within living cells. We evaluated the performance of our assay in HTS setting using the pharmacologic controls (JNJ-40418677 and MK-591) and by screening a Library of Pharmacologically Active Compounds (LOPAC). The results confirmed the feasibility of our assay for compound library screening to identify potential ZIKV protease inhibitors.

Despite the efforts towards malaria eradication, latest estimates show that the number of malaria cases is still rising, and malaria continues to have a devastating impact on people's health and livelihoods particularly in populations located in sub-Saharan Africa ¹. As a Product Development Partnership (PDP), MMV Medicines for Malaria Venture (MMV) plays a crucial role by using public and philanthropic funds to engage the pharmaceutical industry and academic research institutions to discover, develop and deliver the new drugs needed to control and eradicate malaria. MMV Discovery, working with partners, has developed a robust pipeline of molecules and a reliable discovery engine able to support research projects from screening to candidate nomination, providing access to centers of expertise and evaluating the profile and potential of molecules. To efficiently support this malaria discovery effort, MMV and its partners have established a state-of-the-art compound management network, supporting all discovery activities. This network serves both discovery projects and open innovation initiatives, such as MMV Open, tailoring workflows to align with distinct project objectives. In addition to this, MMV has implemented reliable integrated logistic tools and interfaces. These tools enable the efficient management and tracking of individual not solubilized (dry) samples of project compounds, as well as dedicated, solubilized libraries of compounds designated for primary screens targeting malaria and other neglected diseases.

Zinc is an essential trace element that is involved in many biological processes and in cellular homeostasis. In pancreatic β-cells, zinc is crucial for the synthesis, processing, and secretion of insulin, which plays a key role in glucose homeostasis and which deficiency is the cause of diabetes. The accumulation of zinc in pancreatic cells is regulated by the solute carrier transporter SLC30A8 (or Zinc Transporter 8, ZnT8), which transports zinc from cytoplasm in intracellular vesicles. Allelic variants of SLC30A8 gene have been linked to diabetes. Given the physiological intracellular localization of SLC30A8 in pancreatic β-cells and the ubiquitous endogenous expression of other Zinc transporters in different cell lines that could be used as cellular model for SLC30A8 recombinant over-expression, it is challenging to develop a functional assay to measure SLC30A8 activity. To achieve this goal, we have firstly generated a HEK293 cell line stably overexpressing SLC30A8, where the over-expression favors the partial localization of SLC30A8 on the plasma membrane. Then, we used the combination of this cell model, commercial FluoZin-3 cell permeant zinc dye and live cell imaging approach to follow zinc flux across SLC30A8 over-expressed on plasma membrane, thus developing a novel functional imaging- based assay specific for SLC30A8. Our novel approach can be further explored and optimized, paving the way for future small molecule medium-throughput screening.

Organ-on-chip (OOC) models can be useful tools for cancer drug discovery. Advances in OOC technology have led to the development of more complex assays, yet analysis of these systems does not always account for these advancements, resulting in technical challenges. A challenging task in the analysis of these two-channel microfluidic models is to define the boundary between the channels so objects moving within and between channels can be quantified. We propose a novel imaging-based application of a thin plate spline method – a generalized cubic spline that can be used to model coordinate transformations – to model a tissue boundary and define compartments for quantification of invaded objects, representing the early steps in cancer metastasis. To evaluate its performance, we applied our analytical approach to an adapted OOC developed by Emulate, Inc., utilizing a two-channel system with endothelial cells in the bottom channel and colorectal cancer (CRC) patient-derived organoids (PDOs) in the top channel. Initial application and visualization of this method revealed boundary variations due to microscope stage tilt and ridge and valley-like contours in the endothelial tissue surface. The method was functionalized into a reproducible analytical process and web tool – the Chip Invasion and Contour Analysis (ChICA) – to model the endothelial surface and quantify invading tumor cells across multiple chips. To illustrate applicability of the analytical method, we applied the tool to CRC organoid-chips seeded with two different endothelial cell types and measured distinct variations in endothelial surfaces and tumor cell invasion dynamics. Since ChICA utilizes only positional data output from imaging software, the method is applicable to and agnostic of the imaging tool and image analysis system used. The novel thin plate spline method developed in ChICA can account for variation introduced in OOC manufacturing or during the experimental workflow, can quickly and accurately measure tumor cell invasion, and can be used to explore biological mechanisms in drug discovery.

Methylation of proteins and nucleic acids plays a fundamental role in epigenetic regulation, and discovery of methyltransferase (MT) inhibitors is an area of intense activity. Because of the diversity of MTs and their products, assay methods that detect S-adenosylhomocysteine (SAH) – the invariant product of S-adenosylmethionine (SAM)-dependent methylation reactions - offer some advantages over methods that detect specific methylation events. However, direct, homogenous detection of SAH requires a reagent capable of discriminating between SAH and SAM, which differ by a single methyl group. Moreover, MTs are slow enzymes and many have submicromolar affinities for SAM; these properties translate to a need for detection of SAH at low nanomolar concentrations in the presence of excess SAM. To meet these needs, we leveraged the exquisite molecular recognition properties of a naturally occurring SAH-sensing RNA aptamer, or riboswitch. By splitting the riboswitch into two fragments, such that SAH binding induces assembly of a trimeric complex, we engineered sensors that transduce binding of SAH into positive fluorescence polarization (FP) and time resolved Förster resonance energy transfer (TR-FRET) signals. The split riboswitch configuration, called the AptaFluor™ SAH Methyltransferase Assay, allows robust detection of SAH (Z’ > 0.7) at concentrations below 10 nM, with overnight signal stability in the presence of typical MT assay components. The AptaFluor assay tolerates diverse MT substrates, including histones, nucleosomes, DNA and RNA, and we demonstrated its utility as a robust, enzymatic assay method for several methyltransferases with SAM K_m values < 1 µM. The assay was validated for HTS by performing a pilot screen of 1,280 compounds against the SARS-CoV-2 RNA capping enzyme, nsp14. By enabling direct, homogenous detection of SAH at low nanomolar concentrations, the AptaFluor assay provides a universal platform for screening and profiling MTs at physiologically relevant SAM concentrations.