A phenotypic high-throughput screen
using ∼100,000 compounds
prepared using Diversity-Oriented Synthesis yielded stereoisomeric
compounds with nanomolar growth-inhibition activity against the parasite Trypanosoma cruzi, the etiological agent of Chagas disease.
After evaluating stereochemical dependence on solubility, plasma protein
binding and microsomal stability, the SSS analogue (5) was chosen for structure–activity relationship studies.
The p-phenoxy benzyl group appended to the secondary
amine could be replaced with halobenzyl groups without loss in potency.
The exocyclic primary alcohol is not needed for activity but the isonicotinamide
substructure is required for activity. Most importantly, these compounds
are trypanocidal and hence are attractive as drug leads for both acute
and chronic stages of Chagas disease. Analogue (5) was
nominated as the molecular libraries probe ML341 and
is available through the Molecular Libraries Probe Production Centers
Trypanosoma cruzi; diversity-oriented
synthesis; Chagas disease; neglected disease; high-throughput screening; phenotypic assay; infectious disease; Molecular Libraries Probe Production
Ferroptosis is a form of nonapoptotic cell death for which key regulators remain unknown. We sought a common mediator for the lethality of 12 ferroptosisinducing small molecules. We used targeted metabolomic profiling to discover that depletion of glutathione causes inactivation of glutathione peroxidases (GPXs) in response to one class of compounds and a chemoproteomics strategy to discover that GPX4 is directly inhibited by a second class of compounds. GPX4 overexpression and knockdown modulated the lethality of 12 ferroptosis inducers, but not of 11 compounds with other lethal mechanisms. In addition, two representative ferroptosis inducers prevented tumor growth in xenograft mouse tumor models. Sensitivity profiling in 177 cancer cell lines revealed that diffuse large B cell lymphomas and renal cell carcinomas are particularly susceptible to GPX4-regulated ferroptosis. Thus, GPX4 is an essential regulator of ferroptotic cancer cell death.
Autophagy is an evolutionarily conserved catabolic process that directs cytoplasmic proteins, organelles and microbes to lysosomes for degradation. Autophagy acts at the intersection of pathways involved in cellular stress, host defense, and modulation of inflammatory and immune responses; however, the details of how the autophagy network intersects with these processes remain largely undefined. Given the role of autophagy in several human diseases, it is important to determine the extent to which modulators of autophagy also modify inflammatory or immune pathways, and whether it is possible to modulate a subset of these pathways selectively. Here, we identify small-molecule inducers of basal autophagy (including several FDA-approved drugs) and characterize their effects on IL-1β production, autophagic engulfment and killing of intracellular bacteria, and development of Treg, TH17, and TH1 subsets from naïve T cells. Autophagy inducers with distinct, selective activity profiles were identified that reveal the functional architecture of connections between autophagy, and innate and adaptive immunity. In macrophages from mice bearing a conditional deletion of the essential autophagy gene Atg16L1, the small molecules inhibit IL-1β production to varying degrees suggesting that individual compounds may possess both autophagy-dependent and autophagy-independent activity on immune pathways. The small molecule autophagy inducers constitute useful probes to test the contributions of autophagy-related pathways in diseases marked by impaired autophagy or elevated IL-1β, and to test novel therapeutic hypotheses.
Background & Aims
Intestinal epithelial cells aid in mucosal defense by providing a physical barrier against entry of pathogenic bacteria and secreting anti-microbial peptides (AMPs). Autophagy is an important component of immune homeostasis. However, little is known about its role in specific cell types during bacterial infection in vivo. We investigated the role of autophagy in the response of intestinal epithelial and antigen-presenting cells to Salmonella infection in mice.
We generated mice deficient in Atg16l1 in epithelial cells (Atg16l1f/f x Villin-cre) or CD11c+ cells (Atg16l1f/f x CD11c-cre); these mice were used to assess cell type-specific, anti-bacterial autophagy. All responses were compared to Atg16l1f/f mice (controls). Mice were infected with Salmonella enterica serovar Typhimurium; cecum and small intestine tissues were collected for immunofluorescence, histology, and quantitative reverse transcription PCR analyses of cytokines and AMPs. Modulators of autophagy were screened to evaluate their effects on anti-bacterial responses in human epithelial cells.
Autophagy was induced in small intestine and cecum following infection with S Typhimurium, and required Atg16l1. S Typhimurium colocalized with microtubule-associated protein 1 light chain 3 beta (Map1lc3b or LC3) in the intestinal epithelium of control mice but not in Atg16l1f/f x Villin-cre mice. Atg16l1f/f x Villin-cre mice also had fewer Paneth cells and abnormal granule morphology, leading to reduced expression of AMP. Consistent with these defective immune responses, Atg16l1f/f x Villin-cre mice had increased inflammation and systemic translocation of bacteria compared with control mice. In contrast, we observed few differences between Atg16l1f/f x CD11c-cre and control mice. Trifluoperazine promoted autophagy and bacterial clearance in HeLa cells; these effects were reduced upon knockdown of ATG16L1.
Atg16l1 regulates autophagy in intestinal epithelial cells and is required for bacterial clearance. It is also required to prevent systemic infection of mice with enteric bacteria.
mouse model; autophagy; intestinal barrier; mucosa
The high rate of clinical response to protein kinase-targeting drugs matched to cancer patients with specific genomic alterations has prompted efforts to use cancer cell-line (CCL) profiling to identify additional biomarkers of small-molecule sensitivities. We have quantitatively measured the sensitivity of 242 genomically characterized CCLs to an Informer Set of 354 small molecules that target many nodes in cell circuitry, uncovering protein dependencies that: 1) associate with specific cancer-genomic alterations and 2) can be targeted by small molecules. We have created the Cancer Therapeutics Response Portal (www.broadinstitute.org/ctrp) to enable users to correlate genetic features to sensitivity in individual lineages and control for confounding factors of CCL profiling. We report a candidate dependency, associating activating mutations in the oncogene β-catenin with sensitivity to the Bcl2-family antagonist, navitoclax. The resource can be used to develop novel therapeutic hypotheses and accelerate discovery of drugs matched to patients by their cancer genotype and lineage.
A catalytic asymmetric Passerini reaction using tridentate indan (pybox) Cu(II) Lewis acid complex 4 with substrates capable of bidentate coordination has been achieved. The reaction occurs via ligand-accelerated catalysis.
Substrates having appendages that pre-encode skeletal information (σ-elements) can be converted into products having distinct skeletons using a common set of reaction conditions. The sequential use of the Ugi 4CC-IMDA reaction, followed by allylation, hydrolysis, and acylation of a chiral amino alcohol appendage (σ-element), leads to substrates for a ROM/RCM or RCM reaction. The stereochemistry of the σ-element and not its constitution controls the outcome of the pathway selected. This work illustrates the potential of linking stereochemical control to the challenging problem of skeletal diversity.
Lenalidomide is a drug with clinical efficacy in multiple myeloma and other B cell neoplasms, but its mechanism of action is unknown. Using quantitative proteomics, we found that lenalidomide causes selective ubiquitination and degradation of two lymphoid transcription factors, IKZF1 and IKZF3, by the CRBN-CRL4 ubiquitin ligase. IKZF1 and IKZF3 are essential transcription factors in multiple myeloma. A single amino acid substitution of IKZF3 conferred resistance to lenalidomide-induced degradation and rescued lenalidomide-induced inhibition of cell growth. Similarly, we found that lenalidomide-induced IL2 production in T cells is due to depletion of IKZF1 and IKZF3. These findings reveal a novel mechanism of action for a therapeutic agent, alteration of the activity of an E3 ubiquitin ligase leading to selective degradation of specific targets.
Pancreatic and duodenal homeobox 1 (PDX1), a member of the homedomain-containing transcription factor family, is a key transcription factor important for both pancreas development and mature beta-cell function. The ectopic overexpression of Pdx1, Neurog3, and MafA in mice reprograms acinar cells to insulin-producing cells. We developed a qPCR-based gene-expression assay to screen >60,000 compounds for expression of each of these genes in the human PANC-1 ductal carcinoma cell line. We identified BRD7552, which up-regulated PDX expression in both primary human islets and ductal cells, and induced epigenetic changes in the PDX1 promoter consistent with transcriptional activation. Prolonged compound treatment induced insulin mRNA and protein, and enhanced insulin expression induced by the three-gene combination. These results provide a proof of principle for identifying small molecules that induce expression of transcription factors to control cellular reprogramming.
Efforts to develop more effective therapies for acute leukemia may benefit from high-throughput screening systems that reflect the complex physiology of the disease, including leukemia stem cells (LSCs) and supportive interactions with the bone-marrow microenvironment. The therapeutic targeting of LSCs is challenging because LSCs are highly similar to normal hematopoietic stem and progenitor cells (HSPCs) and are protected by stromal cells in vivo. We screened 14,718 compounds in a leukemia-stroma co-culture system for inhibition of cobblestone formation, a cellular behavior associated with stem-cell function. Among those that inhibited malignant cells but spared HSPCs was the cholesterol-lowering drug lovastatin. Lovastatin showed anti-LSC activity in vitro and in an in vivo bone marrow transplantation model. Mechanistic studies demonstrated that the effect was on-target, via inhibition of HMGCoA reductase. These results illustrate the power of merging physiologically-relevant models with high-throughput screening.
Genetic findings have suggested that neuregulin-1 (Nrg1) and its receptor v-erb-a erythroblastic leukemia viral oncogene homologue 4 (ErbB4) may play a role in neuropsychiatric diseases. However, the downstream signaling events and relevant phenotypic consequences of altered Nrg1 signaling in the nervous system remain poorly understood. To identify small molecules for probing Nrg1−ErbB4 signaling, a PC12-cell model was developed and used to perform a live-cell, image-based screen of the effects of small molecules on Nrg1-induced neuritogenesis. By comparison of the resulting phenotypic data to that of a similar screening performed with nerve growth factor (NGF), this multidimensional screen identified compounds that directly inhibit Nrg1−ErbB4 signaling, such as the 4-anilino-quinazoline Iressa (gefitinib), as well as compounds that potentiate Nrg1−ErbB4 signaling, such as the indolocarbazole K-252a. These findings provide new insights into the regulation of Nrg1−ErbB4 signaling events and demonstrate the feasibility of using such a multidimensional, chemical-genetic approach for discovering probes of pathways implicated in neuropsychiatric diseases.
Neuregulin; ErbB4; automated imaging; neuritogenesis; quinazoline; indolocarbazole
A high-throughput screen (HTS) of the MLPCN library using a homogenous fluorescence polarization assay identified a small molecule as a first-in-class direct inhibitor of Keap1-Nrf2 protein-protein interaction. The HTS hit has three chiral centers; a combination of flash and chiral chromatographic separation demonstrated that Keap1-binding activity resides predominantly in one stereoisomer (SRS)-5 designated as ML334 (LH601A), which is at least 100× more potent than the other stereoisomers. The stereochemistry of the four cis isomers was assigned using X-ray crystallography and confirmed using stereospecific synthesis. (SRS)-5 is functionally active in both an ARE gene reporter assay and an Nrf2 nuclear translocation assay. The stereospecific nature of binding between (SRS)-5 and Keap1 as well as the preliminary but tractable structure-activity relationships support its use as a lead for our ongoing optimization.
Keap1; Nrf2; Inhibitors of protein-protein interaction; Nrf2 activation
Type-1 diabetes (T1D) is an autoimmune disease in which insulin-secreting pancreatic beta cells are destroyed by the immune system. An emerging strategy to regenerate beta-cell mass is through transdifferentiation of pancreatic alpha cells to beta cells. We previously reported two small molecules, BRD7389 and GW8510, that induce insulin expression in a mouse alpha cell line and provide a glimpse into potential intermediate cell states in beta-cell reprogramming from alpha cells. These small-molecule studies suggested that inhibition of kinases in particular may induce the expression of several beta-cell markers in alpha cells. To identify potential lineage reprogramming protein targets, we compared the transcriptome, proteome, and phosphoproteome of alpha cells, beta cells, and compound-treated alpha cells. Our phosphoproteomic analysis indicated that two kinases, BRSK1 and CAMKK2, exhibit decreased phosphorylation in beta cells compared to alpha cells, and in compound-treated alpha cells compared to DMSO-treated alpha cells. Knock-down of these kinases in alpha cells resulted in expression of key beta-cell markers. These results provide evidence that perturbation of the kinome may be important for lineage reprogramming of alpha cells to beta cells.
Radiation therapy is one of the mainstays of anti-cancer treatment, but the relationship between the radiosensitivity of cancer cells and their genomic characteristics is still not well-defined. Here we report the development of a high-throughput platform for measuring radiation survival in vitro and its validation by comparison to conventional clonogenic radiation survival analysis. We combined results from this high-throughput assay with genomic parameters in cell lines from squamous cell lung carcinoma, which is standardly treated by radiation therapy, to identify parameters that predict radiation sensitivity. We showed that activation of NFE2L2, a frequent event in lung squamous cancers, confers radiation resistance. An expression-based, in silico screen nominated inhibitors of PI3K as NFE2L2 antagonists. We showed that the selective PI3K inhibitor, NVP-BKM120, both decreased NRF2 protein levels and sensitized NFE2L2 or KEAP1 mutant cells to radiation. We then combined results from this high-throughput assay with single-sample gene set enrichment analysis (ssGSEA) of gene expression data. The resulting analysis identified pathways implicated in cell survival, genotoxic stress, detoxification, and innate and adaptive immunity as key correlates of radiation sensitivity. The integrative, high-throughput methods shown here for large-scale profiling of radiation survival and genomic features of solid-tumor derived cell lines should facilitate tumor radiogenomics and the discovery of genotype-selective radiation sensitizers and protective agents.
TP53; cmap; radiomodifier
Piperlongumine (PL) is a naturally occurring small molecule previously shown to induce cell death preferentially in cancer cells relative to non-cancer cells. An initial effort to synthesize analogs highlighted the reactivities of both of piperlongumine's α,β-unsaturated imide functionalities as key features determining PL's cellular effects. In this study, a second-generation of analogs was synthesized and evaluated in cells to gain further insight into how the reactivity, number, and orientation of PL's reactive olefins contribute to its ability to alter the physiology of cells.
Michael acceptors; reactive oxygen species; piperlongumine; toxicity
ChemBank (http://chembank.broad.harvard.edu/) is a public, web-based informatics environment developed through a collaboration between the Chemical Biology Program and Platform at the Broad Institute of Harvard and MIT. This knowledge environment includes freely available data derived from small molecules and small-molecule screens and resources for studying these data. ChemBank is unique among small-molecule databases in its dedication to the storage of raw screening data, its rigorous definition of screening experiments in terms of statistical hypothesis testing, and its metadata-based organization of screening experiments into projects involving collections of related assays. ChemBank stores an increasingly varied set of measurements derived from cells and other biological assay systems treated with small molecules. Analysis tools are available and are continuously being developed that allow the relationships between small molecules, cell measurements, and cell states to be studied. Currently, ChemBank stores information on hundreds of thousands of small molecules and hundreds of biomedically relevant assays that have been performed at the Broad Institute by collaborators from the worldwide research community. The goal of ChemBank is to provide life scientists unfettered access to biomedically relevant data and tools heretofore available primarily in the private sector.
The KRAS oncogene is found in up to 30% of all human
2009, RNAi experiments revealed that lowering mRNA levels of a transcript
encoding the serine/threonine kinase STK33 was selectively toxic to
KRAS-dependent cancer cell lines, suggesting that small-molecule inhibitors
of STK33 might selectively target KRAS-dependent cancers. To test
this hypothesis, we initiated a high-throughput screen using compounds
in the Molecular Libraries Small Molecule Repository (MLSMR). Several
hits were identified, and one of these, a quinoxalinone derivative,
was optimized. Extensive SAR studies were performed and led to the
chemical probe ML281 that showed low nanomolar inhibition of purified
recombinant STK33 and a distinct selectivity profile as compared to
other STK33 inhibitors that were reported in the course of these studies.
Even at the highest concentration tested (10 μM), ML281 had
no effect on the viability of KRAS-dependent cancer cells. These results
are consistent with other recent reports using small-molecule STK33
inhibitors. Small molecules having different chemical structures and
kinase-selectivity profiles are needed to fully understand the role
of STK33 in KRAS-dependent cancers. In this regard, ML281 is a valuable
addition to small-molecule probes of STK33.
STK33 inhibitor; KRAS synthetic lethality; MLPCN probe
Computational methods for image-based profiling are under active development, but their success hinges on assays that can capture a wide range of phenotypes. We have developed a multiplex cytological profiling assay that “paints the cell” with as many fluorescent markers as possible without compromising our ability to extract rich, quantitative profiles in high throughput. The assay detects seven major cellular components. In a pilot screen of bioactive compounds, the assay detected a range of cellular phenotypes and it clustered compounds with similar annotated protein targets or chemical structure based on cytological profiles. The results demonstrate that the assay captures subtle patterns in the combination of morphological labels, thereby detecting the effects of chemical compounds even though their targets are not stained directly. This image-based assay provides an unbiased approach to characterize compound- and disease-associated cell states to support future probe discovery.
Macrocyclic Hedgehog (Hh) pathway inhibitors have been
with improved potency and maximal inhibition relative to the previously
reported macrocycle robotnikinin. Analogues were prepared using a
modular and efficient build-couple-pair (BCP) approach, with a ring-closing
metathesis step to form the macrocyclic ring. Varying the position
of the macrocycle nitrogen and oxygen atoms provided inhibitors with
improved activity in cellular assays; the most potent analogue was 29 (BRD-6851), with an IC50 of 0.4 μM against
C3H10T1/2 cells undergoing Hh-induced activation, as measured by Gli1 transcription and alkaline phosphatase induction. Studies
with Patched knockout (Ptch–/–) cells and competition studies with the Smoothened (Smo) agonists
SAG and purmorphamine demonstrate that in contrast to robotnikinin,
select analogues are Smo antagonists.
macrocycle; diversity-oriented synthesis (DOS); Sonic Hedgehog pathway; Smoothened antagonist; C3H10T1/2
The mechanism by which cells decide to skip mitosis to become polyploid is largely undefined. Here we used a high-content image-based screen to identify small-molecule probes that induce polyploidization of megakaryocytic leukemia cells and serve as perturbagens to help understand this process. We found that dimethylfasudil (diMF, H-1152P) selectively increased polyploidization, mature cell-surface marker expression, and apoptosis of malignant megakaryocytes. A broadly applicable, highly integrated target identification approach employing proteomic and shRNA screening revealed that a major target of diMF is Aurora A kinase (AURKA), which has not been studied extensively in megakaryocytes. Moreover, we discovered that MLN8237 (Alisertib), a selective inhibitor of AURKA, induced polyploidization and expression of mature megakaryocyte markers in AMKL blasts and displayed potent anti-AMKL activity in vivo. This research provides the rationale to support clinical trials of MLN8237 and other inducers of polyploidization in AMKL. Finally, we have identified five networks of kinases that regulate the switch to polyploidy.
Hedgehog signaling pathway is involved in the development of
multicellular organisms and, when deregulated, can contribute to certain
cancers, among other diseases. The molecular characterization of the
pathway, which has been enabled by small-molecule probes targeting
its components, remains incomplete. Here, we report the discovery
of two potent, small-molecule inhibitors of the Sonic Hedgehog (Shh)
pathway, BRD50837 and BRD9526. Both compounds exhibit stereochemistry-based
structure–activity relationships, a feature suggestive of a
specific and selective interaction of the compounds with as-yet-unknown
cellular target(s) and made possible by the strategy used to synthesize
them as members of a stereochemically and skeletally diverse screening
collection. The mechanism-of-action of these compounds in some ways
shares similarities to that of cyclopamine, a commonly used pathway
inhibitor. Yet, in other ways their mechanism-of-action is strikingly
distinct. We hope that these novel compounds will be useful probes
of this complex signaling pathway.
Long-term memory formation is known to be critically dependent upon de novo gene expression in the brain. As a consequence, pharmacological enhancement of the transcriptional processes mediating long-term memory formation provides a potential therapeutic strategy for cognitive disorders involving aberrant neuroplasticity. Here we focus on the identification and characterization of small molecule inhibitors of histone deacetylases (HDACs) as enhancers of CREB (cAMP response element-binding protein)-regulated transcription and modulators of chromatin-mediated neuroplasticity. Using a CREB reporter gene cell line, we screened a library of small molecules structurally related to known HDAC inhibitors leading to the identification of a probe we termed crebinostat that produced robust activation of CREB-mediated transcription. Further characterization of crebinostat revealed its potent inhibition of the deacetylase activity of recombinant class I HDACs 1, 2, 3, and class IIb HDAC6, with weaker inhibition of the class I HDAC8 and no significant inhibition of the class IIa HDACs 4, 5, 7, and 9. In cultured mouse primary neurons, crebinostat potently induced acetylation of both histone H3 and histone H4 as well as enhanced the expression of the CREB target gene Egr1 (early growth response 1). Using a hippocampus-dependent, contextual fear conditioning paradigm, mice systemically administered crebinostat for a ten day time period exhibited enhanced memory. To gain insight into the molecular mechanisms of memory enhancement by HDAC inhibitors, whole genome transcriptome profiling of cultured mouse primary neurons treated with crebinostat, combined with bioinformatic analyses of CREB-target genes, was performed revealing a highly connected protein-protein interaction network reflecting modules of genes important to synaptic structure and plasticity. Consistent with these findings, crebinostat treatment increased the density of synapsin-1 punctae along dendrites in cultured neurons. Finally, crebinostat treatment of cultured mouse primary neurons was found to upregulate Bdnf (brain-derived neurotrophic factor) and Grn (granulin) and downregulate Mapt (tau) gene expression—genes implicated in aging-related cognitive decline and cognitive disorders. Taken together, these results demonstrate that crebinostat provides a novel probe to modulate chromatin-mediated neuroplasticity and further suggests that pharmacological optimization of selective of HDAC inhibitors may provide an effective therapeutic approach for human cognitive disorders.
Cognitive enhancer; histone deacetylases; epigenetic; chromatin; acetylation; CREB
Cytokine-induced beta-cell apoptosis is important to the etiology of type-1 diabetes. Although previous reports have shown that general inhibitors of histone deacetylase (HDAC) activity, such as suberoylanilide hydroxamic acid and trichostatin A, can partially prevent beta-cell death, they do not fully restore beta-cell function. To understand HDAC isoform selectivity in beta cells, we measured the cellular effects of eleven structurally diverse HDAC inhibitors on cytokine-induced apoptosis in the rat INS-1E cell line. All eleven compounds restored ATP levels and reduced nitrite secretion. However, caspase-3 activity was reduced only by MS-275 and CI-994, both of which target HDAC1, 2, and 3. Importantly, both MS-275 and genetic knock-down of Hdac3 alone were sufficient to restore glucose-stimulated insulin secretion in the presence of cytokines. These results suggest that HDAC3-selective inhibitors may be effective in preventing cytokine-induced beta-cell apoptosis.
of reactive oxygen species (ROS) levels has been observed
in many cancer cells relative to nontransformed cells, and recent
reports have suggested that small-molecule enhancers of ROS may selectively
kill cancer cells in various in vitro and in vivo models. We used a high-throughput screening approach
to identify several hundred small-molecule enhancers of ROS in a human
osteosarcoma cell line. A minority of these compounds diminished the
viability of cancer cell lines, indicating that ROS elevation by small
molecules is insufficient to induce death of cancer cell lines. Three
chemical probes (BRD5459, BRD56491, BRD9092) are highlighted that
most strongly elevate markers of oxidative stress without causing
cell death and may be of use in a variety of cellular settings. For
example, combining nontoxic ROS-enhancing probes with nontoxic doses
of l-buthionine sulfoximine, an inhibitor of glutathione
synthesis previously studied in cancer patients, led to potent cell
death in more than 20 cases, suggesting that even nontoxic ROS-enhancing
treatments may warrant exploration in combination strategies. Additionally,
a few ROS-enhancing compounds that contain sites of electrophilicity,
including piperlongumine, show selective toxicity for transformed
cells over nontransformed cells in an engineered cell-line model of
tumorigenesis. These studies suggest that cancer cell lines are more
resilient to chemically induced increases in ROS levels than previously
thought and highlight electrophilicity as a property that may be more
closely associated with cancer-selective cell death than ROS elevation.
A high-throughput screen of the NIH-MLSMR compound collection,
along with a series of secondary assays to identify potential targets
of hit compounds, previously identified a 1,3-diaminobenzene scaffold
that targets protease-activated receptor 1 (PAR1). We now report additional
structure–activity relationship (SAR) studies that delineate
the requirements for activity at PAR1 and identify plasma-stable analogues
with nanomolar inhibition of PAR1-mediated platelet activation. Compound 4 was declared as a probe (ML161) with the NIH Molecular Libraries
Program. This compound inhibited platelet aggregation induced by a
PAR1 peptide agonist or by thrombin but not by several other platelet
agonists. Initial studies suggest that ML161 is an allosteric inhibitor
of PAR1. These findings may be important for the discovery of antithrombotics
with an improved safety profile.
platelet activation; PAR1 inhibitor; allosteric
inhibitor; 1,3-diaminobenzene; ML161; MLPCN