SLAS Discovery

Sorafenib is a multikinase inhibitor indicated for first-line treatment of unresectable hepatocellular carcinoma. Despite its widespread use in the clinic, the existing knowledge of sorafenib mode-of-action remains incomplete. To build upon the current understanding, we used the Cellular Thermal Shift Assay (CETSA) coupled to Mass Spectrometry (CETSA-MS) to monitor compound binding to its target proteins in the cellular context on a proteome-wide scale. Among the potential sorafenib targets, we identified aldehyde dehydrogenase 2 (ALDH2), an enzyme that plays a major role in alcohol metabolism...

Cathepsin L (CTSL), a lysosomal cysteine proteinase, is primarily dedicated to the metabolic turnover of intracellular proteins. It is involved in various physiological processes and contributes to pathological conditions such as viral infection, tumor invasion and metastasis, inflammatory status, atherosclerosis, renal disease, diabetes, bone diseases, and other ailments. The coronavirus disease 2019 (COVID-19), with its rapid global spread and significant mortality, has been a worldwide epidemic since the late 2019s...

In June 2022, EU-OS came to the decision to make public a solubility data set of 100+K compounds obtained from several of the EU-OS proprietary screening compound collections. Leveraging on the interest of SLAS for screening scientific development it was decided to launch a joint EUOS-SLAS competition within the chemoinformatic and machine learning (ML) communities. The competition was open to real world computation experts, for the best, most predictive, classification model of compound solubility. The aim of the competition was multiple: from a practical side, the winning model should then serve as a cornerstone for future solubility predictions having used the largest training set so far publicly available...

The purpose of the protocol reported in this work is the solubility profiling of large chemical libraries using nephelometry. This technique allows the qualitative classification of compounds as highly, moderately, or poorly water-soluble. The described methodology is not intended to yield quantitative solubility values of the studied compounds but can be used as a primary solubility assessment of large chemical libraries, to guide hit prioritization after High Throughput Screening (HTS) campaigns.

Pediatric brain tumors (PBTs) represent about 25% of all pediatric cancers and are the most common solid tumors in children and adolescents. Medulloblastoma (MB) is the most frequently occurring malignant PBT, accounting for almost 10% of all pediatric cancer deaths. MB Group 3 (MB G3) accounts for 25-30% of all MB cases and has the worst outcome, particularly when associated with MYC amplification. However, no targeted treatments for this group have been developed so far. Here we describe a unique high throughput screening (HTS) platform specifically designed to identify new therapies for MB G3...

The EUOS/SLAS challenge aimed to facilitate the development of reliable algorithms to predict the aqueous solubility of small molecules using experimental data from 100K compounds. In total, hundred teams took part in the challenge to predict low, medium and highly soluble compounds as measured by the nephelometry assay. This article describes the winning model, which was developed using the publicly available Online CHEmical database and Modeling environment (OCHEM) available on the website https://ochem.eu/article/​​27...

Here we offer perspectives on phenotypic screening based on a wide-ranging discussion entitled "Phenotypic screening, target ID, and multi-omics: enabling more disease relevance in early discovery?" at the Screen Design and Assay Technology Special Interest Group Meeting at the 2023 SLAS Conference. During the session, the authors shared their own experience from within their respective organizations, followed by an open discussion with the audience. It was recognized that while substantial progress has been made towards translating disease-relevant phenotypic early discovery into clinical success, there remain significant operational and scientific challenges to implementing phenotypic screening efforts, and improving translation of screening hits comes with substantial resource demands and organizational commitment...

SARS-CoV-2 nsp13 helicase is an essential enzyme for viral replication and a promising target for antiviral drug development. This study compares the double-stranded RNA (dsRNA) unwinding activity of nsp13 and the Omicron nsp13R392C variant, which is predominant in currently circulating lineages. Using in vitro gel- and fluorescence-based assays, we found that both nsp13 and nsp13R392C have dsRNA unwinding activity with equivalent kinetics. Furthermore, the R392C mutation had no effect on the efficiency of the nsp13-specific helicase inhibitor SSYA10-001...

Three-dimensional (3D) cell culture in vitro promises to improve representation of neuron physiology in vivo. This inspired development of a 3D culture platform for LUHMES (Lund Human Mesencephalic) dopaminergic neurons for high-throughput screening (HTS) of chemicals for neurotoxicity. Three culture platforms, adhesion (2D-monolayer), 3D-suspension, and 3D-shaken, were compared to monitor mRNA expression of seven neuronal marker genes, DCX, DRD2, ENO2, NEUROD4, SYN1, TH, and TUBB3. These seven marker genes reached similar maxima in all three formats, with the two 3D platforms showing similar kinetics, whereas several markers peaked earlier in 2D adhesion compared to both 3D culture platforms...

Covalent hits for drug discovery campaigns are neither fantastic beasts nor mythical creatures, they can be routinely identified through electrophile-first screening campaigns using a suite of different techniques. These include biophysical and biochemical methods, cellular approaches, and DNA-encoded libraries. Employing best practice, however, is critical to success. The purpose of this review is to look at state of the art covalent hit identification, how to identify hits from a covalent library and how to select compounds for medicinal chemistry programmes...

High Throughput Screening (HTS) with 3D cell models is possible thanks to the recent progress and development in 3D cell culture technologies. Results from multiple studies have demonstrated different drug responses between 2D and 3D cell culture. It is now widely accepted that 3D cell models more accurately represent the physiologic conditions of tumors over 2D cell models. However, there is still a need for more accurate tests that are scalable and better imitate the complex conditions in living tissues. Here, we describe ultrahigh throughput 3D methods of drug response profiling in patient derived primary tumors including melanoma as well as renal cell carcinoma that were tested against the NCI oncologic set of FDA approved drugs...

The use of recombinant antibodies developed through phage display technology offers a promising approach for combating viral infectious diseases. By specifically targeting antigens on viral surfaces, these antibodies have the potential to reduce the severity of infections or even prevent them altogether. With the emergence of new and more virulent strains of viruses, it is crucial to develop innovative methods to counteract them. Phage display technology has proven successful in generating recombinant antibodies capable of targeting specific viral antigens, thereby providing a powerful tool to fight viral infections...

Micro/nano topological modification is critical for improving the in vivo behaviors of bone implants, regulating multiple cellular functions. Titania (TiO2 ) nanotubes show the capacity of promoting osteoblast-related cell differentiation and induce effective osseointegration, serving as a model material for studying the effects of micro/nano-topological modifications on cells. However, the intracellular signaling pathways by which TiO2 nanotubes regulate the osteogenic differentiation of stem cells are not fully defined...

The pivotal role of myofibroblast contractility in the pathophysiology of fibrosis is widely recognized, yet HTS approaches are not available to quantify this critically important function in drug discovery. We developed, validated, and scaled-up a HTS platform that quantifies contractile function of primary human lung myofibroblasts upon treatment with pro-fibrotic TGF-β1. With the fully automated assay we screened a library of 40,000 novel small molecules in under 80 h of total assay run-time. We identified 42 hit compounds that inhibited the TGF-β1-induced contractile phenotype of myofibroblasts, and enriched for 19 that specifically target myofibroblasts but not phenotypically related smooth muscle cells...

Aberrant protein aggregation is a pathological cellular hallmark of many neurodegenerative diseases, such as Alzheimer's disease (AD) and frontotemporal dementia (FTD), where the tau protein is aggregating, forming neurofibrillary tangles (NFTs), and propagating from neuron to neuron. These processes have been linked to disease progression and a decline in cognitive function. Various therapeutic approaches aim at the prevention or reduction of tau aggregates in neurons. Human induced pluripotent stem cells (hiPSCs) are a very valuable tool in neuroscience discovery, as they offer access to potentially unlimited amounts of cell types that are affected in disease, including cortical neurons, for in vitro studies...

Molecular glues are small molecules, typically smaller than PROTACs, and usually with improved physicochemical properties that aim to stabilise the interaction between two proteins. Most often this approach is used to improve or induce an interaction between the target and an E3 ligase, but other interactions which stabilise interactions to increase activity or to inhibit binding to a natural effector have also been demonstrated. This review will describe the effects of induced proximity, discuss current methods used to identify molecular glues and introduce approaches that could be adapted for molecular glue screening...

Three-dimensional (3D) cell culture technology has been steadily studied since the 1990's due to its superior biocompatibility compared to the conventional two-dimensional (2D) cell culture technology, and has recently developed into an organoid culture technology that further improved biocompatibility. Since the 3D culture of human cell lines in artificial scaffolds was demonstrated in the early 90's, 3D cell culture technology has been actively developed owing to various needs in the areas of disease research, precision medicine, new drug development, and some of these technologies have been commercialized...

In solid tumors like head and neck cancer (HNC), chronic and acute hypoxia have serious adverse clinical consequences including poorer overall patient prognosis, enhanced metastasis, increased genomic instability, and resistance to radiation-, chemo-, or immuno-therapies. However, cells in the two-dimensional monolayer cultures typically used for cancer drug discovery experience 20%-21% O2 levels (normoxic) which are 4-fold higher than O2 levels in normal tissues and ≥10-fold higher than in the hypoxic regions of solid tumors...

Establishment of drug testing of patient-derived cancer cells (PDCs) in physiologically relevant 3-dimensional (3D) culture is central for drug discovery and cancer research, as well as for functional precision medicine. Here, we describe the detailed protocol allowing the 3D drug testing of PDCs - or any type of cells of interest - in Matrigel in 384-well plate format using automation. We also provide an alternative protocol, which does not require supporting matrices. The cancer tissue is obtained directly from clinics (after surgery or biopsy) and processed into single cell suspension...

The cellular thermal shift assay (CETSA®) is a target engagement method widely used for preclinical characterization of small molecule compounds. CETSA® has been used for semi-quantitative readouts in whole blood with PBMC isolation, and quantitative, plate-based readouts using cell lines. However, there has been no quantitative evaluation of CETSA® in unprocessed human whole blood, which is preferred for clinical applications. Here we report two separate assay formats - Alpha CETSA® and MSD CETSA® - that require less than 100 μL of whole blood per sample without PBMC isolation...