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result(s) for
"Rankovic, Zoran"
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Structural basis for substrate recognition and chemical inhibition of oncogenic MAGE ubiquitin ligases
2020
Testis-restricted melanoma antigen (MAGE) proteins are frequently hijacked in cancer and play a critical role in tumorigenesis. MAGEs assemble with E3 ubiquitin ligases and function as substrate adaptors that direct the ubiquitination of novel targets, including key tumor suppressors. However, how MAGEs recognize their targets is unknown and has impeded the development of MAGE-directed therapeutics. Here, we report the structural basis for substrate recognition by MAGE ubiquitin ligases. Biochemical analysis of the degron motif recognized by MAGE-A11 and the crystal structure of MAGE-A11 bound to the PCF11 substrate uncovered a conserved substrate binding cleft (SBC) in MAGEs. Mutation of the SBC disrupted substrate recognition by MAGEs and blocked MAGE-A11 oncogenic activity. A chemical screen for inhibitors of MAGE-A11:substrate interaction identified 4-Aminoquinolines as potent inhibitors of MAGE-A11 that show selective cytotoxicity. These findings provide important insights into the large family of MAGE ubiquitin ligases and identify approaches for developing cancer-specific therapeutics.
Testis-restricted melanoma antigen (MAGE) proteins function as substrate adapters for E3 ubiquitin ligases. Biochemical and structural analyses of MAGE-A11 provide insight into the substrate binding mode of MAGE proteins and enable discovery of potent, cytotoxic inhibitors of MAGE-A11:substrate interaction.
Journal Article
Patient-derived models recapitulate heterogeneity of molecular signatures and drug response in pediatric high-grade glioma
by
Mercer, Kimberly S.
,
Dunphy, Paige S.
,
Twarog, Nathaniel
in
1-Phosphatidylinositol 3-kinase
,
13/106
,
38/39
2021
Pediatric high-grade glioma (pHGG) is a major contributor to cancer-related death in children. In vitro and in vivo disease models reflecting the intimate connection between developmental context and pathogenesis of pHGG are essential to advance understanding and identify therapeutic vulnerabilities. Here we report establishment of 21 patient-derived pHGG orthotopic xenograft (PDOX) models and eight matched cell lines from diverse groups of pHGG. These models recapitulate histopathology, DNA methylation signatures, mutations and gene expression patterns of the patient tumors from which they were derived, and include rare subgroups not well-represented by existing models. We deploy 16 new and existing cell lines for high-throughput screening (HTS). In vitro HTS results predict variable in vivo response to PI3K/mTOR and MEK pathway inhibitors. These unique new models and an online interactive data portal for exploration of associated detailed molecular characterization and HTS chemical sensitivity data provide a rich resource for pediatric brain tumor research.
Patient-derived xenografts provide a resource for basic and translational cancer research. Here, the authors generate multiple pediatric high-grade glioma xenografts, use omics technologies to show that they are representative of primary tumours and use them to assess therapeutic response.
Journal Article
Selective CK1α degraders exert antiproliferative activity against a broad range of human cancer cell lines
2024
Molecular-glue degraders are small molecules that induce a specific interaction between an E3 ligase and a target protein, resulting in the target proteolysis. The discovery of molecular glue degraders currently relies mostly on screening approaches. Here, we describe screening of a library of cereblon (CRBN) ligands against a panel of patient-derived cancer cell lines, leading to the discovery of SJ7095, a potent degrader of CK1α, IKZF1 and IKZF3 proteins. Through a structure-informed exploration of structure activity relationship (SAR) around this small molecule we develop SJ3149, a selective and potent degrader of CK1α protein in vitro and in vivo. The structure of SJ3149 co-crystalized in complex with CK1α + CRBN + DDB1 provides a rationale for the improved degradation properties of this compound. In a panel of 115 cancer cell lines SJ3149 displays a broad antiproliferative activity profile, which shows statistically significant correlation with MDM2 inhibitor Nutlin-3a. These findings suggest potential utility of selective CK1α degraders for treatment of hematological cancers and solid tumors.
Here, the authors describe a potent and selective CK1a molecular glue degrader with a broad antiproliferative potency. Crystallographic data provide rationale for the high degradation efficacy displayed by this compound.
Journal Article
Unbiased mapping of cereblon neosubstrate landscape by high-throughput proteomics
2025
Molecular glue degraders (MGDs) are small molecules that co-opt the ubiquitin-proteasome system to induce degradation of target proteins, including those considered undruggable. Their discovery remains challenging due to the lack of rational design strategies and limited throughput of unbiased proteome-wide screening approaches. To address this gap, we develop a high-throughput proteomics platform based on label-free, data-independent acquisition mass spectrometry (DIA-MS), enabling integrated proteomics and ubiquitinomics profiling. Screening a diverse set of 100 cereblon (CRBN)-recruiting ligands on this platform leads to identification of a broad array of novel degraders and neosubstrates. Subsequent hit validation and structure-degradation relationship analyses guided by global proteomics reveal highly selective and potent phenyl glutarimide-based degraders targeting previously uncharacterized neosubstrates such as KDM4B, G3BP2 and VCL; none of which contain the classical CRBN β-hairpin degron. These findings underscore the power of unbiased high-throughput proteomics in MGD drug discovery and reveal a substantially expanded CRBN neosubstrate landscape beyond that defined by classical immunomodulatory imid drugs (IMiDs).
Molecular glue degraders (MGD) offer a way to target undruggable proteins, but their discovery is challenging. Here, the authors develop a high-throughput proteomics platform for MGD drug discovery, revealing a much larger cereblon neosubstrate space than initially thought.
Journal Article
Capmatinib is an effective treatment for MET-fusion driven pediatric high-grade glioma and synergizes with radiotherapy
by
Budd, Kaitlin M.
,
Roach, Jordan T.
,
Twarog, Nathaniel
in
Anilides - pharmacology
,
Animals
,
Benzamides - pharmacology
2024
Background
Pediatric-type diffuse high-grade glioma (pHGG) is the most frequent malignant brain tumor in children and can be subclassified into multiple entities. Fusion genes activating the MET receptor tyrosine kinase often occur in infant-type hemispheric glioma (IHG) but also in other pHGG and are associated with devastating morbidity and mortality.
Methods
To identify new treatment options, we established and characterized two novel orthotopic mouse models harboring distinct MET fusions. These included an immunocompetent, murine allograft model and patient-derived orthotopic xenografts (PDOX) from a MET-fusion IHG patient who failed conventional therapy and targeted therapy with cabozantinib. With these models, we analyzed the efficacy and pharmacokinetic properties of three MET inhibitors, capmatinib, crizotinib and cabozantinib, alone or combined with radiotherapy.
Results
Capmatinib showed superior brain pharmacokinetic properties and greater
in vitro
and
in vivo
efficacy than cabozantinib or crizotinib in both models. The PDOX models recapitulated the poor efficacy of cabozantinib experienced by the patient. In contrast, capmatinib extended survival and induced long-term progression-free survival when combined with radiotherapy in two complementary mouse models. Capmatinib treatment increased radiation-induced DNA double-strand breaks and delayed their repair.
Conclusions
We comprehensively investigated the combination of MET inhibition and radiotherapy as a novel treatment option for MET-driven pHGG. Our seminal preclinical data package includes pharmacokinetic characterization, recapitulation of clinical outcomes, coinciding results from multiple complementing
in vivo
studies, and insights into molecular mechanism underlying increased efficacy. Taken together, we demonstrate the groundbreaking efficacy of capmatinib and radiation as a highly promising concept for future clinical trials.
Journal Article
Ca2+-mediated mitochondrial inner membrane permeabilization induces cell death independently of Bax and Bak
by
Min, Jaeki
,
Llambi, Fabien
,
Rankovic, Zoran
in
Apoptosis
,
Bcl-2 protein
,
Calcium (intracellular)
2022
The ability of mitochondria to buffer a rapid rise in cytosolic Ca2+ is a hallmark of proper cell homeostasis. Here, we employed m-3M3FBS, a putative phospholipase C (PLC) agonist, to explore the relationships between intracellular Ca2+ imbalance, mitochondrial physiology, and cell death. m-3M3FBS induced a potent dose-dependent Ca2+ release from the endoplasmic reticulum (ER), followed by a rise in intra-mitochondrial Ca2+. When the latter exceeded the organelle buffering capacity, an abrupt mitochondrial inner membrane permeabilization (MIMP) occurred, releasing matrix contents into the cytosol. MIMP was followed by cell death that was independent of Bcl-2 family members and inhibitable by the intracellular Ca2+ chelator BAPTA-AM. Cyclosporin A (CsA), capable of blocking the mitochondrial permeability transition (MPT), completely prevented cell death induced by m-3M3FBS. However, CsA acted upstream of mitochondria by preventing Ca2+ release from ER stores. Therefore, loss of Ca2+ intracellular balance and mitochondrial Ca2+ overload followed by MIMP induced a cell death process that is distinct from Bcl-2 family-regulated mitochondrial outer membrane permeabilization (MOMP). Further, the inhibition of cell death by CsA or its analogues can be independent of effects on the MPT.
Journal Article
Continuous collective analysis of chemical reactions
by
Torres-Hernandez, Arnaldo X.
,
Ochoada, Jason
,
Twarog, Nathaniel
in
639/638/11/296
,
639/638/549/2132/605
,
639/638/77/888
2024
The automated synthesis of small organic molecules from modular building blocks has the potential to transform our capacity to create medicines and materials
1
,
2
–
3
. Disruptive acceleration of this molecule-building strategy broadly unlocks its functional potential and requires the integration of many new assembly chemistries. Although recent advances in high-throughput chemistry
4
,
5
–
6
can speed up the development of appropriate synthetic methods, for example, in selecting appropriate chemical reaction conditions from the vast range of potential options, equivalent high-throughput analytical methods are needed. Here we report a streamlined approach for the rapid, quantitative analysis of chemical reactions by mass spectrometry. The intrinsic fragmentation features of chemical building blocks generalize the analyses of chemical reactions, allowing sub-second readouts of reaction outcomes. Central to this advance was identifying that starting material fragmentation patterns function as universal barcodes for downstream product analysis by mass spectrometry. Combining these features with acoustic droplet ejection mass spectrometry
7
,
8
we could eliminate slow chromatographic steps and continuously evaluate chemical reactions in multiplexed formats. This enabled the assignment of reaction conditions to molecules derived from ultrahigh-throughput chemical synthesis experiments. More generally, these results indicate that fragmentation features inherent to chemical synthesis can empower rapid data-rich experimentation.
Mass spectrometry fragmentation patterns define analytical barcodes for the rapid, quantitative analysis of high-throughput chemical synthesis experiments.
Journal Article
Lead generation approaches in drug discovery
by
Morphy, Richard
,
Rankovic, Zoran
in
Drug development
,
Drug Discovery -- methods
,
Drugs -- Design
2010
An integrated overview of modern approaches to lead discovery Lead generation is increasingly seen as a distinct and success-determining phase of the drug discovery process. Over recent years, there have been major advances in the understanding of what constitutes a good lead compound and how to improve the chances of finding such a compound. Written by leading scientists and established opinion leaders from industry and academia, this book provides an authoritative overview of the field, as well as the theory, practice, and scope, of the principal Lead Generation Approaches in Drug Discovery, including: The evolution of the lead discovery process, key concepts, current challenges, and future directions Strategies and technologies driving the high-throughput screening (HTS) approach to lead discovery, including the shifting paradigms in the design of compound collections and best practice in the hit confirmation process Knowledge-based in silico or \"virtual\" screening Theory and practice of the fragment-based approach to lead discovery The opportunities and challenges presented by multi-target drug discovery (MTDD) De novo design of lead compounds and new approaches to estimating the synthetic accessibility of de novo-designed molecules The impact of natural products on drug discovery, and potential of natural product-like compounds for exploring regions of biologically relevant chemical space Using early screening of hits and leads for metabolic, pharmacokinetic, and toxicological liabilities to reduce attrition during the later phases of drug discovery The utility of parallel synthesis and purification in lead discovery With each topic supported by numerous case studies, this is indispensable reading for researchers in industry and academia who wish to keep up to date with the latest strategies and approaches in drug discovery.
Designing CNS Drugs for Optimal Brain Exposure
2015
The great majority of CNS drugs are small molecules that are designed to cross the blood–brain barrier (BBB) via the transcellular passive diffusion route. Achieving optimal brain exposure is a unique and major challenge for medicinal chemists working on the CNS targets. Design strategies toward such molecules and their physicochemical properties are the main foci of this chapter. The existence of the BBB renders classic pharmacokinetic (PK) parameters, such as oral bioavailability and plasma concentration, insufficient for assessing CNS drug candidates due to uncertainty regarding whether such parameters will reflect the time course or exposure levels in the brain. Several key physicochemical properties have been identified that influence the rate of brain permeability and the extent of brain penetration including H‐bonding potential, molecular weights (MWs), lipophilicity, polar surface area (PSA), ionization state, and rotatable bond count.
Book Chapter