canSAR: update to the cancer translational research and drug discovery knowledgebase.

canSAR (http://cansar.icr.ac.uk) is the largest, public, freely available, integrative translational research and drug discovery knowledgebase for oncology. canSAR integrates vast multidisciplinary data from across genomic, protein, pharmacological, drug and chemical data with structural biology, protein networks and more. It also provides unique data, curation and annotation and crucially, AI-informed target assessment for drug discovery. canSAR is widely used internationally by academia and industry. Here we describe significant developments and enhancements to the data, web interface and infrastructure of canSAR in the form of the new implementation of the system: canSARblack. We demonstrate new functionality in aiding translation hypothesis generation and experimental design, and show how canSAR can be adapted and utilised outside oncology.

A Chemical Probe for the ATAD2 Bromodomain.

ATAD2 is a cancer-associated protein whose bromodomain has been described as among the least druggable of that target class. Starting from a potent lead, permeability and selectivity were improved through a dual approach: 1) using CF2 as a sulfone bio-isostere to exploit the unique properties of fluorine, and 2) using 1,3-interactions to control the conformation of a piperidine ring. This resulted in the first reported low-nanomolar, selective and cell permeable chemical probe for ATAD2.

Advances and challenges in understanding histone demethylase biology.

Within the last decade we have witnessed significant progress in the field of chromatin methylation, ranging from the discovery that chromatin methylation is reversible, to the identification of two classes of oxidative chromatin demethylases. Multiple genetic and cellular studies emphasize the role of members of the amine oxidase and 2-oxoglutarate oxygenase enzyme families involved in methyl-lysine in physiology and disease. Advances in understanding of the underlying biochemistry have resulted in development of first series of clinical inhibitors and tool compounds which continue to resolve and help understand the complex relationships between chromatin modification, control of gene expression and metabolic states.

Discovery of I-BRD9, a Selective Cell Active Chemical Probe for Bromodomain Containing Protein 9 Inhibition.

Acetylation of histone lysine residues is one of the most well-studied post-translational modifications of chromatin, selectively recognized by bromodomain "reader" modules. Inhibitors of the bromodomain and extra terminal domain (BET) family of bromodomains have shown profound anticancer and anti-inflammatory properties, generating much interest in targeting other bromodomain-containing proteins for disease treatment. Herein, we report the discovery of I-BRD9, the first selective cellular chemical probe for bromodomain-containing protein 9 (BRD9). I-BRD9 was identified through structure-based design, leading to greater than 700-fold selectivity over the BET family and 200-fold over the highly homologous bromodomain-containing protein 7 (BRD7). I-BRD9 was used to identify genes regulated by BRD9 in Kasumi-1 cells involved in oncology and immune response pathways and to the best of our knowledge, represents the first selective tool compound available to elucidate the cellular phenotype of BRD9 bromodomain inhibition.

Generation of a Selective Small Molecule Inhibitor of the CBP/p300 Bromodomain for Leukemia Therapy.

The histone acetyltransferases CBP/p300 are involved in recurrent leukemia-associated chromosomal translocations and are key regulators of cell growth. Therefore, efforts to generate inhibitors of CBP/p300 are of clinical value. We developed a specific and potent acetyl-lysine competitive protein-protein interaction inhibitor, I-CBP112, that targets the CBP/p300 bromodomains. Exposure of human and mouse leukemic cell lines to I-CBP112 resulted in substantially impaired colony formation and induced cellular differentiation without significant cytotoxicity. I-CBP112 significantly reduced the leukemia-initiating potential of MLL-AF9(+) acute myeloid leukemia cells in a dose-dependent manner in vitro and in vivo. Interestingly, I-CBP112 increased the cytotoxic activity of BET bromodomain inhibitor JQ1 as well as doxorubicin. Collectively, we report the development and preclinical evaluation of a novel, potent inhibitor targeting CBP/p300 bromodomains that impairs aberrant self-renewal of leukemic cells. The synergistic effects of I-CBP112 and current standard therapy (doxorubicin) as well as emerging treatment strategies (BET inhibition) provide new opportunities for combinatorial treatment of leukemia and potentially other cancers.

5-Carboxy-8-hydroxyquinoline is a Broad Spectrum 2-Oxoglutarate Oxygenase Inhibitor which Causes Iron Translocation.

2-Oxoglutarate and iron dependent oxygenases are therapeutic targets for human diseases. Using a representative 2OG oxygenase panel, we compare the inhibitory activities of 5-carboxy-8-hydroxyquinoline (IOX1) and 4-carboxy-8-hydroxyquinoline (4C8HQ) with that of two other commonly used 2OG oxygenase inhibitors, N-oxalylglycine (NOG) and 2,4-pyridinedicarboxylic acid (2,4-PDCA). The results reveal that IOX1 has a broad spectrum of activity, as demonstrated by the inhibition of transcription factor hydroxylases, representatives of all 2OG dependent histone demethylase subfamilies, nucleic acid demethylases and γ-butyrobetaine hydroxylase. Cellular assays show that, unlike NOG and 2,4-PDCA, IOX1 is active against both cytosolic and nuclear 2OG oxygenases without ester derivatisation. Unexpectedly, crystallographic studies on these oxygenases demonstrate that IOX1, but not 4C8HQ, can cause translocation of the active site metal, revealing a rare example of protein ligand-induced metal movement.

Plant growth regulator daminozide is a selective inhibitor of human KDM2/7 histone demethylases.

The JmjC oxygenases catalyze the N-demethylation of N(ε)-methyl lysine residues in histones and are current therapeutic targets. A set of human 2-oxoglutarate analogues were screened using a unified assay platform for JmjC demethylases and related oxygenases. Results led to the finding that daminozide (N-(dimethylamino)succinamic acid, 160 Da), a plant growth regulator, selectively inhibits the KDM2/7 JmjC subfamily. Kinetic and crystallographic studies reveal that daminozide chelates the active site metal via its hydrazide carbonyl and dimethylamino groups.

Imperfect interface of Beclin1 coiled-coil domain regulates homodimer and heterodimer formation with Atg14L and UVRAG.

Beclin 1 is a core component of the Class III Phosphatidylinositol 3-Kinase VPS34 complex. The coiled coil domain of Beclin 1 serves as an interaction platform for assembly of distinct Atg14L- and UVRAG-containing complexes to modulate VPS34 activity. Here we report the crystal structure of the coiled coil domain that forms an antiparallel dimer and is rendered metastable by a series of 'imperfect' a-d' pairings at its coiled coil interface. Atg14L and UVRAG promote the transition of metastable homodimeric Beclin 1 to heterodimeric Beclin1-Atg14L/UVRAG assembly. Beclin 1 mutants with their 'imperfect' a-d' pairings modified to enhance self-interaction, show distinctively altered interactions with Atg14L or UVRAG. These results suggest that specific utilization of the dimer interface and modulation of the homodimer-heterodimer transition by Beclin 1-interacting partners may underlie the molecular mechanism that controls the formation of various Beclin1-VPS34 subcomplexes to exert their effect on an array of VPS34-related activities, including autophagy.

A selective inhibitor and probe of the cellular functions of Jumonji C domain-containing histone demethylases.

Histone methylations are important chromatin marks that regulate gene expression, genomic stability, DNA repair, and genomic imprinting. Histone demethylases are the most recent family of histone-modifying enzymes discovered. Here, we report the characterization of a small-molecule inhibitor of Jumonji C domain-containing histone demethylases. The inhibitor derives from a structure-based design and preferentially inhibits the subfamily of trimethyl lysine demethylases. Its methyl ester prodrug, methylstat, selectively inhibits Jumonji C domain-containing his-tone demethylases in cells and may be a useful small-molecule probe of chromatin and its role in epigenetics.