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Graphical abstract Abstract The protein-protein interaction between WDR5 (WD40 repeat protein 5) and MLL1 (mixed-lineage leukemia 1) is important for maintaining optimal H3K4 methyltransferase activity of MLL1. Dysregulation of MLL1 catalytic function is relevant to mixed-lineage leukemia, and targeting WDR5-MLL1 interaction could be a promising therapeutic strategy for leukemia harboring MLL1 fusion proteins. To date, several peptidomimetic and non-peptidomimetic small-molecule inhibitors targeting WDR5-MLL1 interaction have been reported, yet the discovery walk of new drugs inhibiting MLL1 methytransferase activity is still in its infancy. It's urgent to find other small-molecule WDR5-MLL1 inhibitors with novel scaffolds. In this study, through fluorescence polarization (FP)-based high throughput screening, several small-molecule inhibitors with potent inhibitory activities in vitro against WDR5-MLL1 interaction were discovered. Nuclear Magnetic Resonance (NMR) assays were carried out to confirm the direct binding between hit compounds and WDR5. Subsequent similarity-based analog searching of the 4 hits led to several inhibitors with better activity, among them, DC_M5_2 displayed highest inhibitory activity with IC 50 values of 9.63 ± 1.46 µM. Furthermore, a molecular docking study was performed and disclosed the binding modes and interaction mechanisms between two most potent inhibitors and WDR5. [ABSTRACT FROM AUTHOR]

Abstract Although mutated Ras protein is well recognized as an important drug target, direct targeting Ras has proven to be a daunting task. Recent studies demonstrated that Ras protein needs PDEδ to relocate to plasma membrane to execute its signaling transduction function, which provides a new avenue for modulating the Ras protein. To find small molecules antagonizing the interactions between PDEδ and Ras, here we presented a successful application of fragment-based drug discovery of PDEδ inhibitors. Under the guidance of crystal structures, we are able to quickly optimize the initial fragment into highly potent inhibitors, with more than 2000-fold improvement in binding activity, which further adds to the arsenal towards the inhibition of Ras signaling in cancer therapy. Graphical abstract Image 1 Highlights • Fragment-based approach was used to discover a new chemotype targeting PDEδ-Ras interaction. • Scaffold modification was undertaken on the basis of co-crystal structure and resulted in an optimizable hit. • Two rounds of optimization quickly improved the binding activity by more than 1000 fold. • Biological study indicates the PDEδ-Ras inhibitor could affect the downstream Ras signaling. [ABSTRACT FROM AUTHOR]

The Rho family GTPases are crucial drivers of tumor growth and metastasis. However, it is difficult to develop GTPases inhibitors due to a lack of well‐characterized binding pockets for compounds. Here, through molecular dynamics simulation of the RhoA protein, a groove around cysteine 107 (Cys107) that is relatively well‐conserved within the Rho family is discovered. Using a combined strategy, the novel inhibitor DC‐Rhoin is discovered, which disrupts interaction of Rho proteins with guanine nucleotide exchange factors (GEFs) and guanine nucleotide dissociation inhibitors (GDIs). Crystallographic studies reveal that the covalent binding of DC‐Rhoin to the Cys107 residue stabilizes and captures a novel allosteric pocket. Moreover, the derivative compound DC‐Rhoin04 inhibits the migration and invasion of cancer cells, through targeting this allosteric pocket of RhoA. The study reveals a novel allosteric regulatory site within the Rho family, which can be exploited for anti‐metastasis drug development, and also provides a novel strategy for inhibitor discovery toward "undruggable" protein targets. [ABSTRACT FROM AUTHOR]

• The selective BPTF bromodomain inhibitor was identified via virtual screening. • A HTRF platform for biochemical evaluation of BPTF bromodomain was established. • NMR and SPR demonstrated the interactions between DCB29 and BPTF bromodomain. • Molecular docking revealed the binding mode between DCB29 and BPTF bromodomain. Bromodomain PHD finger transcription factor (BPTF), a bromodomain-containing protein, plays a crucial role in the regulation of downstream gene expression through the specific recognition of lysine acetylation on bulk histones. The dysfunction of BPTF is closely involved with the development and progression of many human diseases, especially cancer. Therefore, BPTF bromodomain has become a promising drug target for epigenetic cancer therapy. However, unlike BET family inhibitors, few BPTF bromodomain inhibitors have been reported. In this study, by integrating docking-based virtual screening with biochemical analysis, we identified a novel selective BPTF bromodomain inhibitor DCB29 with the IC 50 value of 13.2 ± 1.6 μM by homogenous time-resolved fluorescence resonance energy transfer (HTRF) assays. The binding between DCB29 and BPTF was confirmed by NMR and SPR. Molecular docking disclosed that DCB29 occupied the pocket of acetylated H4 peptide substrate and provided detailed SAR explanations for its derivatives. Collectively, DCB29 presented great potential as a powerful tool for BPTF-related biological research and further medicinal chemistry optimization. [ABSTRACT FROM AUTHOR]

DOT1L (the disruptor of telomeric silencing 1-like), through its methyltransferase activity of H3K79, plays essential roles in transcriptional regulation, cell cycle regulation, and DNA damage response. In addition, DOT1L is believed to be involved in the development of MLL-rearranged leukemia driven by the MLL (mixed-lineage leukemia) fusion proteins, which thus to be a crucial target for leukemia therapy. Hence, discovering of novel DOT1L inhibitors has been in a great demand. In this study, we initiated the discovering process from setting up the AlphaLISA based High Throughput Screening (HTS) assay of DOT1L. Combining with radioactive inhibition assay and Surface Plasmon Resonance (SPR) binding assay, we identified compound 3 and its active analogues as novel DOT1L inhibitors with IC 50 values range from 7 μM to 20 μM in vitro . Together with the analysis of structure activity relationships (SAR) and binding modes of these compounds, we provided clues to assist in the future development of more potent DOT1L inhibitors. Moreover, compounds 3 and 9 effectively inhibited the proliferation of MLL-rearranged leukemia cells MV4-11, which could induce cell cycle arrest and apoptosis. In conclusion, we developed a HTS platform based on AlphaLISA method for screening and discovery of DOT1L novel inhibitor, through which we discovered compound 3 and its analogues as potent DOT1L inhibitors with promising MLL-rearranged leukemia therapeutic application. [ABSTRACT FROM AUTHOR]

Summary In the cytoplasm of virtually all clear-cell renal cell carcinoma (ccRCC), speckle-type POZ protein (SPOP) is overexpressed and misallocated, which may induce proliferation and promote kidney tumorigenesis. In normal cells, however, SPOP is located in the nucleus and induces apoptosis. Here we show that a structure-based design and subsequent hit optimization yield small molecules that can inhibit the SPOP-substrate protein interaction and can suppress oncogenic SPOP-signaling pathways. These inhibitors kill human ccRCC cells that are dependent on oncogenic cytoplasmic SPOP. Notably, these inhibitors minimally affect the viability of other cells in which SPOP is not accumulated in the cytoplasm. Our findings validate the SPOP-substrate protein interaction as an attractive target specific to ccRCC that may yield novel drug discovery efforts. [ABSTRACT FROM AUTHOR]

PolycombRepressive Complex 2 (PRC2) modulates the chromatin structureand transcriptional repression by trimethylation lysine 27 of histoneH3 (H3K27me3), a process that necessitates the protein–proteininteraction (PPI) between the catalytic subunit EZH2 and EED. DeregulatedPRC2 is intimately involved in tumorigenesis and progression, makingit an invaluable target for epigenetic cancer therapy. However, untilnow, there have been no reported small molecule compounds targetingthe EZH2-EED interactions. In the present study, we identified astemizole,an FDA-approved drug, as a small molecule inhibitor of the EZH2-EEDinteraction of PRC2. The disruption of the EZH2-EED interaction byastemizole destabilizes the PRC2 complex and inhibits its methyltransferaseactivity in cancer cells. Multiple lines of evidence have demonstratedthat astemizole arrests the proliferation of PRC2-driven lymphomasprimarily by disabling the PRC2 complex. Our findings demonstratethe chemical tractability of the difficult PPI target by a small moleculecompound, highlighting the therapeutic promise for PRC2-driven humancancers via targeted destruction of the EZH2-EED complex. [ABSTRACT FROM AUTHOR]

Approximately 20% of multiple myeloma (MM) are caused by a chromosomal translocation t (4; 14) that leads to the overexpression of the nuclear receptor binding SET domain-protein 2 (NSD2) histone methyltransferase. NSD2 catalyzes the methylation of lysine 36 on histone H3 (H3K36me2) and is associated with transcriptionally active regions. Using high-throughput screening (HTS) with biological analyses, a series of 5-aminonaphthalene derivatives were designed and synthesized as novel NSD2 inhibitors. Among all the prepared compounds, 9c displayed a good NSD2 inhibitory activity (IC 50 = 2.7 μM) and selectivity against both SET-domain-containing and non-SET-domain-containing methyltransferases. Preliminary research indicates the inhibition mechanism of compound 9c by significantly suppressed the methylation of H3K36me2. Compound 9c specifically inhibits the proliferation of the human B cell precursor leukemia cell line RS4:11 and the human myeloma cell line KMS11 by inducing cell cycle arrest and apoptosis with little cytotoxicity. It has been reported that the anti-cancer effect of compound 9c is partly achieved by completely suppressing the transcriptional activation of NSD2-targeted genes. When administered intraperitoneally at 25 mg/kg, compound 9c suppressed the tumor growth of RS4:11 xenografts in vivo and no body weight loss was detected in the tested SCID mice. [Display omitted] • 5-aminonaphthalene derivatives were designed, synthesized and evaluated, the SAR of these compounds was demonstrated. • Compound 9c exhibited a good NSD2 inhibitory activity and inhibited the proliferation of leukemia cell line. • The anti-cancer effect of 9c is partly achieved by suppressing the transcriptional activation of NSD2-targeted genes. • When administered intraperitoneally at 25 mg/kg, compound 9c suppressed the tumor growth of RS4:11 xenografts in vivo. [ABSTRACT FROM AUTHOR]

Transcriptional enhancer associated domain family members (TEADs) are the most important downstream effectors that play the pivotal role in the development, regeneration and tissue homeostasis. Recent biochemical studies have demonstrated that TEADs could undergo autopalmitoylation that is indispensable for its function making the lipid-binding pocket an attractive target for chemical intervention. Herein, through structure-based virtual screen and rational medicinal chemistry optimization, we identified DC-TEADin02 as the most potent, selective, covalent TEAD autopalmitoylation inhibitor with the IC 50 value of 197 ± 19 nM while it showed minimal effect on TEAD-YAP interaction. Further biochemical counter-screens demonstrate the specific thiol reactivity and selectivity of DC-TEADin02 over the kinase family, lipid-binding proteins and epigenetic targets. Notably, DC-TEADin02 inhibited TEADs transcription activity leading to downregulation of YAP-related downstream gene expression. Taken together, our findings proved the validity of modulating transcriptional output in the Hippo signaling pathway through irreversible chemical interventions of TEADs autopalmitoylation activity, which may serve as a qualified chemical tool for TEADs palmitoylation-related studies in the future. Image 1 • DC-TEADin02 is the most potent TEAD autopalmitoylation inhibitor ever reported. • DC-TEADin02 inhibits TEADs transcription activity and downstream gene expression. • DC-TEADin02 shows minimal reactivity with biologically relevant nucleophiles. • DC-TEADin02 is selective over other lipid-binding proteins. • The study demonstrates how virtual screen cooperating with rational optimization. [ABSTRACT FROM AUTHOR]

FTO, an mRNA N6-methyladenosine (m6A) demethylase, was reported to promote leukemogenesis. Using structure-based rational design, we have developed two promising FTO inhibitors, namely FB23 and FB23-2, which directly bind to FTO and selectively inhibit FTO's m6A demethylase activity. Mimicking FTO depletion, FB23-2 dramatically suppresses proliferation and promotes the differentiation/apoptosis of human acute myeloid leukemia (AML) cell line cells and primary blast AML cells in vitro. Moreover, FB23-2 significantly inhibits the progression of human AML cell lines and primary cells in xeno-transplanted mice. Collectively, our data suggest that FTO is a druggable target and that targeting FTO by small-molecule inhibitors holds potential to treat AML. • Structure-guided design and optimization yield potent FTO inhibitors • mRNA m6A acts as the major effector of the inhibitor/FTO axis in AML cells • FTO inhibitor FB23-2 displays therapeutic effects in PDX AML models • Targeting epitranscriptomic RNA methylation holds potential to treat AML Huang et al. use structure-based rational design to develop FB23-2, an inhibitor of the mRNA m6A demethylase FTO. FB23-2 suppresses proliferation and promotes the differentiation of acute myeloid leukemia (AML) cells and prolongs survival of patient-derived AML mouse models. [ABSTRACT FROM AUTHOR]