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Goins, C. M.

Publications and source records attributed to Goins, C. M..

5 recordsLinked to original sources

Fragment-Based Development of NSP14 Exonuclease Inhibitors Confounded by Batch-to-Batch Variability

Point mutations in the exonuclease (ExoN) site of non-structural protein 14 (NSP14) compromise the fitness of betacoronaviruses like SARS-CoV-2, implicating NSP14 ExoN inhibition as an antiviral strategy. However, there are no advanced compounds that inhibit NSP14s ExoN activity. Building upon the reported crystal structures of two fragments bound to NSP14s ExoN site, we identified a series of 3,5-disubsituted pyrazoles that bound to and inhibited NSP14 ExoN. However, upon resynthesis, we discovered that these putative leads were false positives, perhaps due to contaminating divalent cations which potently inhibit NSP14 ExoN. Our results provide a cautionary tale to the field about the sensitivity of NSP14 to divalent cations and illustrate the challenges associated with directly targeting the NSP14 ExoN site via fragment merging.

biochemistry↗

Development and Characterization of Triazole-Based WDR5 Inhibitors for the Treatment of Glioblastoma

Glioblastoma (GBM) cancer stem cells (CSCs) contribute to tumor recurrence, treatment resistance, and dismal clinical outcomes. Genetic and pharmacological evidence suggests that the nuclear scaffolding protein WD-repeat containing protein 5 (WDR5) is a therapeutic vulnerability of the CSC population. However, previously reported WDR5 inhibitors display low permeability and are unable to penetrate the blood-brain barrier (BBB), limiting their utility in GBM. Herein, we report the structure-guided development of a novel series of triazole-based WDR5 WIN-site inhibitors designed to increase passive brain penetration. We identified triazole-based WDR5 inhibitors that are potent, passively permeable, and in some cases more brain penetrant than other scaffolds. We phenotypically assessed our novel WDR5 inhibitors in a panel of patient-derived CSC models and uncovered unique WDR5-regulated metabolic genes in GBM. We also evaluated their antiproliferative activity against CSCs both in vitro and in vivo. Finally, to identify novel combination opportunities, we screened a 2,100-compound chemical probe library and identified that the ATAD2 inhibitor BAY-850 synergizes with WDR5 inhibitors to enhance CSC killing. Our work diversifies the chemical matter targeting WDR5, clarifies the in vitro consequences of WIN-site inhibition in CSCs, and encourages the future development of next-generation WDR5 inhibitors with the potential to achieve in vivo efficacy in the brain.

cancer biology↗

Mechanism and Structure-Guided Optimization of SLC1A1/EAAT3-Selective Inhibitors in Kidney Cancer

Renal Cell Carcinomas (RCCs) depend metabolically on the trimeric sodium-coupled aspartate and glutamate transporter, SLC1A1/EAAT3; however, pharmacologically targeting SLC1A1 is challenging. We determined a cryo-EM structure of human SLC1A1 bound to compound 3e, a recently described SLC1A1-selective bicyclic imidazo[1,211]pyridine-3-amine (BIA) inhibitor. 3e binds a membrane-embedded allosteric pocket accessible only in the apo state, when SLC1A1 is unbound to substrate and sodium, and likely prevents sodium and substrate binding. Moreover, by wedging between the trimerization domain and the substrate-binding transport domain, alongside a cholesterol moiety from the lipid bilayer, 3e blocks SLC1A1s elevator-like movements that are essential for transport. Mutations in this binding pocket abolish 3e interaction and counteract 3es cytotoxicity in RCC cells, confirming on-target activity and explaining SLC1A1 selectivity. A structure-guided medicinal chemistry effort yielded two new SLC1A1-selective BIA derivatives, PBJ1 and PBJ2, with enhanced cytotoxicity resulting from the inhibition of SLC1A1-dependent aspartate, glutamate, and cysteine metabolism.

cancer biology↗

ISGylation of the SARS-CoV-2 N protein by HERC5 impedes N oligomerization and thereby viral RNA synthesis

Interferon (IFN)-stimulated gene 15 (ISG15), a ubiquitin-like protein, is covalently conjugated to host (immune) proteins such as MDA5 and IRF3 in a process called ISGylation, thereby limiting the replication of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, whether SARS-CoV-2 proteins can be directly targeted for ISGylation remains elusive. In this study, we identified the nucleocapsid (N) protein of SARS-CoV-2 as a major substrate of ISGylation catalyzed by the host E3 ligase HERC5; however, N ISGylation is readily removed through de-ISGylation by the papain-like protease (PLpro) activity of NSP3. Mass spectrometry analysis identified that the N protein undergoes ISGylation at four lysine residues (K266, K355, K387 and K388), and mutational analysis of these sites in the context of a SARS-CoV-2 replicon (N-4KR) abolished N ISGylation and alleviated ISGylation-mediated inhibition of viral RNA synthesis. Furthermore, our results indicated that HERC5 targets preferentially phosphorylated N protein for ISGylation to regulate its oligomeric assembly. These findings reveal a novel mechanism by which the host ISGylation machinery directly targets SARS-CoV-2 proteins to restrict viral replication and illuminate how an intricate interplay of host (HERC5) and viral (PLpro) enzymes coordinates viral protein ISGylation and thereby regulates virus replication.

microbiology↗

The WRAD complex represents a therapeutically exploitable target for cancer stem cells in glioblastoma

Glioblastomas (GBMs) are heterogeneous, treatment-resistant tumors that are driven by populations of cancer stem cells (CSCs). Despite their importance for tumor growth, few molecular mechanisms critical for CSC population maintenance have been exploited for therapeutic development. We developed a spatially resolved loss-of-function screen in GBM patient-derived organoids to identify essential epigenetic regulators in the SOX2-enriched, therapy resistant niche and identified WDR5 as indispensable for this population. WDR5 is a component of the WRAD complex, which promotes SET1-family-mediated Lys4 methylation of histone H3, associated with positive regulation of transcription. In GBM CSC models, WDR5 inhibitors blocked WRAD complex assembly and reduced H3K4 trimethylation and expression of genes involved in CSC-relevant oncogenic pathways. H3K4me3 peaks lost with WDR5 inhibitor treatment occurred disproportionally on POU transcription factor motifs, including the POU5F1(OCT4)::SOX2 motif. We incorporated a SOX2/OCT4 motif driven GFP reporter system into our CSC cell models and found that WDR5 inhibitor treatment diminished reporter activity. Further, WDR5 inhibitor treatment altered the stem cell state, disrupting CSC in vitro growth and self-renewal as well as in vivo tumor growth. These findings highlight the role of WDR5 and the WRAD complex in maintaining the CSC state and provide a rationale for therapeutic development of WDR5 inhibitors for GBM and other advanced cancers. SignificanceIn this study, we perform an epigenetic-focused functional genomics screen in glioblastoma organoids and identify WDR5 as an essential epigenetic regulator in the SOX2-enriched, therapy resistant cancer stem cell niche. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=135 HEIGHT=200 SRC="FIGDIR/small/461125v2_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@bc5c5eorg.highwire.dtl.DTLVardef@545a2borg.highwire.dtl.DTLVardef@1ebd3c9org.highwire.dtl.DTLVardef@19d5d30_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗