ABSTRACT
Cyclic dinucleotides (CDN) and Toll-like receptor (TLR) ligands mobilize antitumor responses by natural killer (NK) cells and T cells, potentially serving as complementary therapies to immune checkpoint therapy. In the clinic thus far, however, CDN therapy targeting stimulator of interferon genes (STING) protein has yielded mixed results, perhaps because it initiates responses potently but does not provide signals to sustain activation and proliferation of activated cytotoxic lymphocytes. To improve efficacy, we combined CDN with a half life-extended interleukin-2 (IL-2) superkine, H9-MSA (mouse serum albumin). CDN/H9-MSA therapy induced dramatic long-term remissions of the most difficult to treat major histocompatibility complex class I (MHC I)deficient and MHC I+ tumor transplant models. H9-MSA combined with CpG oligonucleotide also induced potent responses. Mechanistically, tumor elimination required CD8 T cells and not NK cells in the case of MHC I+ tumors and NK cells but not CD8 T cells in the case of MHC-deficient tumors. Furthermore, combination therapy resulted in more prolonged and more intense NK cell activation, cytotoxicity, and expression of cytotoxic effector molecules in comparison with monotherapy. Remarkably, in a primary autochthonous sarcoma model that is refractory to PD-1 checkpoint therapy, the combination of CDN/H9-MSA with checkpoint therapy yielded long-term remissions in the majority of the animals, mediated by T cells and NK cells. This combination therapy has the potential to activate responses in tumors resistant to current therapies and prevent MHC I loss accompanying acquired resistance of tumors to checkpoint therapy.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Histocompatibility Antigens Class I , Immunotherapy , Interleukin-2 , Membrane Proteins , Neoplasms , Nucleotides, Cyclic , Oligodeoxyribonucleotides , Serum Albumin , Animals , CD8-Positive T-Lymphocytes/immunology , Histocompatibility Antigens Class I/genetics , Humans , Immunotherapy/methods , Interleukin-2/immunology , Killer Cells, Natural/immunology , Membrane Proteins/agonists , Mice , Neoplasms/genetics , Neoplasms/therapy , Nucleotides, Cyclic/therapeutic use , Oligodeoxyribonucleotides/therapeutic use , Serum Albumin/therapeutic useABSTRACT
The adenosinergic pathway represents an attractive new therapeutic approach in cancer immunotherapy. In this pathway, ecto-5-nucleotidase CD73 has the unique function of regulating production of immunosuppressive adenosine (ADO) through the hydrolysis of AMP. CD73 is overexpressed in many cancers, resulting in elevated levels of ADO that correspond to poor patient prognosis. Therefore, reducing the level of ADO via inhibition of CD73 is a potential strategy for treating cancers. Based on the binding mode of adenosine 5'-(α,ß-methylene)diphosphate (AOPCP) with human CD73, we designed a series of novel monophosphonate small-molecule CD73 inhibitors. Among them, OP-5244 (35) proved to be a highly potent and orally bioavailable CD73 inhibitor. In preclinical studies, 35 completely inhibited ADO production in both human cancer cells and CD8+ T cells. Furthermore, 35 lowered the ratio of ADO/AMP significantly and reversed immunosuppression in mouse models, indicating its potential as an in vivo tool compound for further development.
Subject(s)
5'-Nucleotidase/antagonists & inhibitors , Adenosine/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Immunologic Factors/pharmacology , Nucleosides/pharmacology , Organophosphonates/pharmacology , Administration, Oral , Animals , CD8-Positive T-Lymphocytes/drug effects , Cell Line, Tumor , Dogs , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , GPI-Linked Proteins/antagonists & inhibitors , Humans , Immunologic Factors/administration & dosage , Immunologic Factors/chemical synthesis , Immunologic Factors/pharmacokinetics , Macaca fascicularis , Mice, Inbred BALB C , Molecular Structure , Nucleosides/administration & dosage , Nucleosides/chemical synthesis , Nucleosides/pharmacokinetics , Organophosphonates/administration & dosage , Organophosphonates/chemical synthesis , Organophosphonates/pharmacokinetics , Rats , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Several immunotherapy approaches that mobilize CD8+ T cell responses stimulate tumor rejection, and some, such as checkpoint blockade, have been approved for several cancer indications and show impressive increases in patient survival. However, tumors may evade CD8+ T cell recognition via loss of MHC molecules or because they contain few or no neoantigens. Therefore, approaches are needed to combat CD8+ T cell-resistant cancers. STING-activating cyclic dinucleotides (CDNs) are a new class of immune-stimulating agents that elicit impressive CD8+ T cell-mediated tumor rejection in preclinical tumor models and are now being tested in clinical trials. Here, we demonstrate powerful CDN-induced, natural killer (NK) cell-mediated tumor rejection in numerous tumor models, independent of CD8+ T cells. CDNs enhanced NK cell activation, cytotoxicity, and antitumor effects in part by inducing type I interferon (IFN). IFN acted in part directly on NK cells in vivo and in part indirectly via the induction of IL-15 and IL-15 receptors, which were important for CDN-induced NK activation and tumor control. After in vivo administration of CDNs, dendritic cells (DCs) up-regulated IL-15Rα in an IFN-dependent manner. Mice lacking the type I IFN receptor specifically on DCs had reduced NK cell activation and tumor control. Therapeutics that activate NK cells, such as CDNs, checkpoint inhibitors, NK cell engagers, and cytokines, may represent next-generation approaches to cancer immunotherapy.
Subject(s)
CD8-Positive T-Lymphocytes/drug effects , CD8-Positive T-Lymphocytes/immunology , Killer Cells, Natural/immunology , Membrane Proteins/agonists , Neoplasms/drug therapy , Neoplasms/immunology , Animals , CRISPR-Cas Systems/drug effects , CRISPR-Cas Systems/immunology , Interferon Type I/pharmacology , Killer Cells, Natural/drug effects , Membrane Proteins/immunology , Mice , Mice, Congenic , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Neoplasms/pathology , Tumor Cells, CulturedABSTRACT
The xishacorene natural products are structurally unique apolar diterpenoids that feature a bicyclo[3.3.1] framework. These secondary metabolites likely arise from the well-studied, structurally related diterpenoid fuscol. In this manuscript, we describe the conversion of fuscol to xishacorenes A, B, and C, as well as a previously unreported congener, which we have named xishacorene D. In addition, we describe immunomodulatory activity studies of the xishacorenes, a structurally related analogue, and fuscol. These studies were aided by an accurate determination of the physical properties (e.g., molar extinction coefficient) of the highly apolar xishacorenes.
ABSTRACT
A series of pyrazolopyrimidine inhibitors of IRAK4 were developed from a high-throughput screen (HTS). Modification of an HTS hit led to a series of bicyclic heterocycles with improved potency and kinase selectivity but lacking sufficient solubility to progress in vivo. Structure-based drug design, informed by cocrystal structures with the protein and small-molecule crystal structures, yielded a series of dihydrobenzofurans. This semisaturated bicycle provided superior druglike properties while maintaining excellent potency and selectivity. Improved physicochemical properties allowed for progression into in vivo experiments, where lead molecules exhibited low clearance and showed target-based inhibition of IRAK4 signaling in an inflammation-mediated PK/PD mouse model.
Subject(s)
Interleukin-1 Receptor-Associated Kinases/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Aminoquinolines/chemical synthesis , Aminoquinolines/metabolism , Aminoquinolines/pharmacology , Animals , Benzofurans/chemical synthesis , Benzofurans/metabolism , Benzofurans/pharmacology , Catalytic Domain , Female , Humans , Interleukin-1 Receptor-Associated Kinases/metabolism , Mice, Inbred C57BL , Molecular Structure , Protein Binding , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/metabolism , Pyrazoles/chemical synthesis , Pyrazoles/metabolism , Pyrimidines/chemical synthesis , Pyrimidines/metabolism , Rats , Signal Transduction/drug effects , Structure-Activity RelationshipABSTRACT
Intratumoral (IT) STING activation results in tumor regression in preclinical models, yet factors dictating the balance between innate and adaptive anti-tumor immunity are unclear. Here, clinical candidate STING agonist ADU-S100 (S100) is used in an IT dosing regimen optimized for adaptive immunity to uncover requirements for a T cell-driven response compatible with checkpoint inhibitors (CPIs). In contrast to high-dose tumor ablative regimens that result in systemic S100 distribution, low-dose immunogenic regimens induce local activation of tumor-specific CD8+ effector T cells that are responsible for durable anti-tumor immunity and can be enhanced with CPIs. Both hematopoietic cell STING expression and signaling through IFNAR are required for tumor-specific T cell activation, and in the context of optimized T cell responses, TNFα is dispensable for tumor control. In a poorly immunogenic model, S100 combined with CPIs generates a survival benefit and durable protection. These results provide fundamental mechanistic insights into STING-induced anti-tumor immunity.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Immunity , Membrane Proteins/metabolism , Neoplasms/immunology , Animals , CTLA-4 Antigen/metabolism , Cell Line, Tumor , Cytokines/metabolism , Dose-Response Relationship, Immunologic , Drug Resistance, Neoplasm , Hematopoiesis , Mice, Inbred BALB C , Mice, Inbred C57BL , Neoplasms/pathology , Programmed Cell Death 1 Receptor/metabolism , S100 Proteins/administration & dosage , S100 Proteins/immunologyABSTRACT
Tumor neoantigens arising from somatic mutations in the cancer genome are less likely to be subject to central immune tolerance and are therefore attractive targets for vaccine immunotherapy. We utilized whole-exome sequencing, RNA sequencing (RNASeq), and an in silico immunogenicity prediction algorithm, NetMHC, to generate a neoantigen-targeted vaccine, PancVAX, which was administered together with the STING adjuvant ADU-V16 to mice bearing pancreatic adenocarcinoma (Panc02) cells. PancVAX activated a neoepitope-specific T cell repertoire within the tumor and caused transient tumor regression. When given in combination with two checkpoint modulators, namely anti-PD-1 and agonist OX40 antibodies, PancVAX resulted in enhanced and more durable tumor regression and a survival benefit. The addition of OX40 to vaccine reduced the coexpression of T cell exhaustion markers, Lag3 and PD-1, and resulted in rejection of tumors upon contralateral rechallenge, suggesting the induction of T cell memory. Together, these data provide the framework for testing personalized neoantigen-based combinatorial vaccine strategies in patients with pancreatic and other nonimmunogenic cancers.
Subject(s)
Adenocarcinoma/therapy , Antineoplastic Agents, Immunological/pharmacology , Cancer Vaccines/administration & dosage , Immunotherapy/methods , Pancreatic Neoplasms/therapy , Adenocarcinoma/genetics , Adenocarcinoma/immunology , Adjuvants, Immunologic/administration & dosage , Animals , Antigens, Neoplasm/genetics , Antigens, Neoplasm/immunology , Antineoplastic Agents, Immunological/therapeutic use , Cancer Vaccines/genetics , Cancer Vaccines/immunology , Cell Line, Tumor/transplantation , Combined Modality Therapy/methods , Disease Models, Animal , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , Humans , Immunogenicity, Vaccine , Membrane Proteins/immunology , Mice , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/immunology , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/immunology , Receptors, OX40/agonists , Receptors, OX40/immunology , Treatment Outcome , Tumor Escape/drug effects , Tumor Escape/immunology , Vaccines, Subunit/administration & dosage , Vaccines, Subunit/genetics , Vaccines, Subunit/immunologyABSTRACT
USP7 is a deubiquitinase implicated in destabilizing the tumor suppressor p53, and for this reason it has gained increasing attention as a potential oncology target for small molecule inhibitors. Herein we describe the biophysical, biochemical, and computational approaches that led to the identification of 4-(2-aminopyridin-3-yl)phenol compounds described by Kategaya ( Nature 2017 , 550 , 534 - 538 ) as specific inhibitors of USP7. Fragment based lead discovery (FBLD) by NMR combined with virtual screening and re-mining of biochemical high-throughput screening (HTS) hits led to the discovery of a series of ligands that bind in the "palm" region of the catalytic domain of USP7 and inhibit its catalytic activity. These ligands were then optimized by structure-based design to yield cell-active molecules with reasonable physical properties. This discovery process not only involved multiple techniques working in concert but also illustrated a unique way in which hits from orthogonal screening approaches complemented each other for lead identification.
Subject(s)
Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Small Molecule Libraries/pharmacology , Ubiquitin-Specific Peptidase 7/antagonists & inhibitors , Aminopyridines/chemistry , Binding Sites , Catalytic Domain , Cell Line , Computer Simulation , Crystallography, X-Ray , Drug Discovery/methods , Drug Evaluation, Preclinical/methods , Humans , Magnetic Resonance Spectroscopy/methods , Oxadiazoles/chemistry , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Ubiquitin-Specific Peptidase 7/chemistry , Ubiquitin-Specific Peptidase 7/metabolismABSTRACT
The ubiquitin system regulates essential cellular processes in eukaryotes. Ubiquitin is ligated to substrate proteins as monomers or chains and the topology of ubiquitin modifications regulates substrate interactions with specific proteins. Thus ubiquitination directs a variety of substrate fates including proteasomal degradation. Deubiquitinase enzymes cleave ubiquitin from substrates and are implicated in disease; for example, ubiquitin-specific protease-7 (USP7) regulates stability of the p53 tumour suppressor and other proteins critical for tumour cell survival. However, developing selective deubiquitinase inhibitors has been challenging and no co-crystal structures have been solved with small-molecule inhibitors. Here, using nuclear magnetic resonance-based screening and structure-based design, we describe the development of selective USP7 inhibitors GNE-6640 and GNE-6776. These compounds induce tumour cell death and enhance cytotoxicity with chemotherapeutic agents and targeted compounds, including PIM kinase inhibitors. Structural studies reveal that GNE-6640 and GNE-6776 non-covalently target USP7 12 Å distant from the catalytic cysteine. The compounds attenuate ubiquitin binding and thus inhibit USP7 deubiquitinase activity. GNE-6640 and GNE-6776 interact with acidic residues that mediate hydrogen-bond interactions with the ubiquitin Lys48 side chain, suggesting that USP7 preferentially interacts with and cleaves ubiquitin moieties that have free Lys48 side chains. We investigated this idea by engineering di-ubiquitin chains containing differential proximal and distal isotopic labels and measuring USP7 binding by nuclear magnetic resonance. This preferential binding protracted the depolymerization kinetics of Lys48-linked ubiquitin chains relative to Lys63-linked chains. In summary, engineering compounds that inhibit USP7 activity by attenuating ubiquitin binding suggests opportunities for developing other deubiquitinase inhibitors and may be a strategy more broadly applicable to inhibiting proteins that require ubiquitin binding for full functional activity.
Subject(s)
Aminopyridines/chemistry , Aminopyridines/pharmacology , Indazoles/chemistry , Indazoles/pharmacology , Phenols/chemistry , Phenols/pharmacology , Pyridines/chemistry , Pyridines/pharmacology , Ubiquitin-Specific Peptidase 7/antagonists & inhibitors , Ubiquitin/metabolism , Animals , Binding, Competitive , Cell Line, Tumor , Drug Synergism , Female , Humans , Mice , Mice, SCID , Models, Molecular , Neoplasms/drug therapy , Neoplasms/enzymology , Neoplasms/pathology , Protein Binding , Proto-Oncogene Proteins c-mdm2/metabolism , Proto-Oncogene Proteins c-pim-1/antagonists & inhibitors , Substrate Specificity , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ubiquitin/chemistry , Ubiquitin-Specific Peptidase 7/chemistry , Ubiquitin-Specific Peptidase 7/deficiency , Ubiquitin-Specific Peptidase 7/metabolismABSTRACT
p21-activated kinase 1 (PAK1) has an important role in transducing signals in several oncogenic pathways. The concept of inhibiting this kinase has garnered significant interest over the past decade, particularly for targeting cancers associated with PAK1 amplification. Animal studies with the selective group I PAK (pan-PAK1, 2, 3) inhibitor G-5555 from the pyrido[2,3-d]pyrimidin-7-one class uncovered acute toxicity with a narrow therapeutic window. To attempt mitigating the toxicity, we introduced significant structural changes, culminating in the discovery of the potent pyridone side chain analogue G-9791. Mouse tolerability studies with this compound, other members of this series, and compounds from two structurally distinct classes revealed persistent toxicity and a correlation of minimum toxic concentrations and PAK1/2 mediated cellular potencies. Broad screening of selected PAK inhibitors revealed PAK1, 2, and 3 as the only overlapping targets. Our data suggest acute cardiovascular toxicity resulting from the inhibition of PAK2, which may be enhanced by PAK1 inhibition, and cautions against continued pursuit of pan-group I PAK inhibitors in drug discovery.
Subject(s)
Cardiovascular Diseases/drug therapy , Protein Kinase Inhibitors/pharmacology , Pyridines/pharmacology , Pyrimidines/pharmacology , p21-Activated Kinases/antagonists & inhibitors , Acute Disease , Animals , Dose-Response Relationship, Drug , Female , Mice , Mice, Inbred BALB C , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Pyridines/chemical synthesis , Pyridines/chemistry , Pyridones , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Structure-Activity Relationship , p21-Activated Kinases/metabolismABSTRACT
Inhibition of phosphoinositide 3-kinase (PI3K) signaling is an appealing approach to treat brain tumors, especially glioblastoma multiforme (GBM). We previously disclosed our successful approach to prospectively design potent and blood-brain barrier (BBB) penetrating PI3K inhibitors. The previously disclosed molecules were ultimately deemed not suitable for clinical development due to projected poor metabolic stability in humans. We, therefore, extended our studies to identify a BBB penetrating inhibitor of PI3K that was also projected to be metabolically stable in human. These efforts required identification of a distinct scaffold for PI3K inhibitors relative to our previous efforts and ultimately resulted in the identification of GDC-0084 (16). The discovery and preclinical characterization of this molecule are described within.
ABSTRACT
Inhibitors of the class I phosphoinositide 3-kinase (PI3K) isoform PI3Kα have received substantial attention for their potential use in cancer therapy. Despite the particular attraction of targeting PI3Kα, achieving selectivity for the inhibition of this isoform has proved challenging. Herein we report the discovery of inhibitors of PI3Kα that have selectivity over the other class I isoforms and all other kinases tested. In GDC-0032 (3, taselisib), we previously minimized inhibition of PI3Kß relative to the other class I insoforms. Subsequently, we extended our efforts to identify PI3Kα-specific inhibitors using PI3Kα crystal structures to inform the design of benzoxazepin inhibitors with selectivity for PI3Kα through interactions with a nonconserved residue. Several molecules selective for PI3Kα relative to the other class I isoforms, as well as other kinases, were identified. Optimization of properties related to drug metabolism then culminated in the identification of the clinical candidate GDC-0326 (4).
Subject(s)
Antineoplastic Agents/pharmacology , Benzoxepins/pharmacology , Drug Design , Imidazoles/pharmacology , Oxazepines/pharmacology , Phosphoinositide-3 Kinase Inhibitors , Protein Kinase Inhibitors/pharmacology , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Benzoxepins/chemistry , Benzoxepins/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Class I Phosphatidylinositol 3-Kinases , Dogs , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Humans , Imidazoles/chemistry , Imidazoles/metabolism , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Macaca fascicularis , Mice , Microsomes, Liver/chemistry , Microsomes, Liver/metabolism , Models, Molecular , Molecular Structure , Oxazepines/chemistry , Oxazepines/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Rats , Rats, Sprague-Dawley , Structure-Activity RelationshipABSTRACT
Signaling pathways intersecting with the p21-activated kinases (PAKs) play important roles in tumorigenesis and cancer progression. By recognizing that the limitations of FRAX1036 (1) were chiefly associated with the highly basic amine it contained, we devised a mitigation strategy to address several issues such as hERG activity. The 5-amino-1,3-dioxanyl moiety was identified as an effective means of reducing pK a and logP simultaneously. When positioned properly within the scaffold, this group conferred several benefits including potency, pharmacokinetics, and selectivity. Mouse xenograft PK/PD studies were carried out using an advanced compound, G-5555 (12), derived from this approach. These studies concluded that dose-dependent pathway modulation was achievable and paves the way for further in vivo investigations of PAK1 function in cancer and other diseases.
ABSTRACT
Diverse biological roles for mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) have necessitated the identification of potent inhibitors in order to study its function in various disease contexts. In particular, compounds that can be used to carry out such studies in vivo would be critical for elucidating the potential for therapeutic intervention. A structure-based design effort coupled with property-guided optimization directed at minimizing the ability of the inhibitors to cross into the CNS led to an advanced compound 13 (GNE-495) that showed excellent potency and good PK and was used to demonstrate in vivo efficacy in a retinal angiogenesis model recapitulating effects that were observed in the inducible Map4k4 knockout mice.
ABSTRACT
Cell migration is a stepwise process that coordinates multiple molecular machineries. Using in vitro angiogenesis screens with short interfering RNA and chemical inhibitors, we define here a MAP4K4-moesin-talin-ß1-integrin molecular pathway that promotes efficient plasma membrane retraction during endothelial cell migration. Loss of MAP4K4 decreased membrane dynamics, slowed endothelial cell migration, and impaired angiogenesis in vitro and in vivo. In migrating endothelial cells, MAP4K4 phosphorylates moesin in retracting membranes at sites of focal adhesion disassembly. Epistasis analyses indicated that moesin functions downstream of MAP4K4 to inactivate integrin by competing with talin for binding to ß1-integrin intracellular domain. Consequently, loss of moesin (encoded by the MSN gene) or MAP4K4 reduced adhesion disassembly rate in endothelial cells. Additionally, α5ß1-integrin blockade reversed the membrane retraction defects associated with loss of Map4k4 in vitro and in vivo. Our study uncovers a novel aspect of endothelial cell migration. Finally, loss of MAP4K4 function suppressed pathological angiogenesis in disease models, identifying MAP4K4 as a potential therapeutic target.
Subject(s)
Cell Movement , Endothelial Cells/cytology , Endothelial Cells/metabolism , Integrins/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Protein Serine-Threonine Kinases/metabolism , Amino Acid Motifs , Animals , Cell Membrane/drug effects , Cell Membrane/metabolism , Cell Shape/drug effects , Endothelial Cells/drug effects , Epistasis, Genetic , Focal Adhesions/metabolism , Humans , Integrin alpha1/drug effects , Integrin alpha1/metabolism , Integrin beta1/chemistry , Integrin beta1/drug effects , Integrin beta1/metabolism , Integrins/drug effects , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/deficiency , Intracellular Signaling Peptides and Proteins/genetics , Male , Mice , Microfilament Proteins/deficiency , Microfilament Proteins/genetics , Microfilament Proteins/metabolism , Neovascularization, Pathologic , Phosphorylation , Protein Binding , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/deficiency , Protein Serine-Threonine Kinases/genetics , Protein Structure, Tertiary , Talin/chemistry , Talin/metabolismABSTRACT
The diverse roles of deubiquitinating enzymes, or DUBs, in determining the fate of specific proteins continue to unfold. Concurrent with the revelation of DUBs as potential therapeutic targets are publications of small molecule inhibitors of these enzymes. In this review, we summarize these molecules and their associated data and suggest additional experiments to further validate and characterize these compounds. We believe the field of drug discovery against DUBs is still in its infancy, but advances in assay development, biophysical techniques, and screening libraries hold promise for identifying suitable agents that could advance into the clinic.
Subject(s)
Enzyme Inhibitors/pharmacology , Ubiquitin-Specific Proteases/antagonists & inhibitors , Crystallography, X-Ray , Drug Discovery , Enzyme Inhibitors/chemistry , Humans , Models, Molecular , Molecular Structure , Structure-Activity Relationship , Ubiquitin-Specific Proteases/metabolismABSTRACT
A-1155463, a highly potent and selective BCL-XL inhibitor, was discovered through nuclear magnetic resonance (NMR) fragment screening and structure-based design. This compound is substantially more potent against BCL-XL-dependent cell lines relative to our recently reported inhibitor, WEHI-539, while possessing none of its inherent pharmaceutical liabilities. A-1155463 caused a mechanism-based and reversible thrombocytopenia in mice and inhibited H146 small cell lung cancer xenograft tumor growth in vivo following multiple doses. A-1155463 thus represents an excellent tool molecule for studying BCL-XL biology as well as a productive lead structure for further optimization.
ABSTRACT
MAP4K4 has been shown to regulate key cellular processes that are tied to disease pathogenesis. In an effort to generate small molecule MAP4K4 inhibitors, a fragment-based screen was carried out and a pyrrolotriazine fragment with excellent ligand efficiency was identified. Further modification of this fragment guided by X-ray crystal structures and molecular modeling led to the discovery of a series of promising compounds with good structural diversity and physicochemical properties. These compounds exhibited single digit nanomolar potency and compounds 35 and 44 achieved good in vivo exposure.
Subject(s)
Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Triazines/pharmacology , Animals , Crystallography, X-Ray , Dose-Response Relationship, Drug , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Ligands , Mice , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/metabolism , Structure-Activity Relationship , Triazines/chemical synthesis , Triazines/chemistry , NF-kappaB-Inducing KinaseABSTRACT
Because of the promise of BCL-2 antagonists in combating chronic lymphocytic leukemia (CLL) and non-Hodgkin's lymphoma (NHL), interest in additional selective antagonists of antiapoptotic proteins has grown. Beginning with a series of selective, potent BCL-XL antagonists containing an undesirable hydrazone functionality, in silico design and X-ray crystallography were utilized to develop alternative scaffolds that retained the selectivity and potency of the starting compounds.