ABSTRACT
Cyclic dinucleotide (CDN) agonists of the STimulator of InterferoN Genes (STING) pathway have shown immune activation and tumor clearance in pre-clinical models. However, CDNs administered intratumorally also promote STING activation leading to direct cytotoxicity of many cell types in the tumor microenvironment (TME), systemic inflammation due to rapid tumor extravasation of the CDN, and immune ablation in the TME. These result in a failure to establish immunological memory. ExoSTING, an engineered extracellular vesicle (EV) exogenously loaded with CDN, enhances the potency of CDN and preferentially activates antigen presenting cells in the TME. Following intratumoral injection, exoSTING was retained within the tumor, enhanced local Th1 responses and recruitment of CD8+ T cells, and generated systemic anti-tumor immunity to the tumor. ExoSTING at therapeutically active doses did not induce systemic inflammatory cytokines, resulting in an enhanced therapeutic window. ExoSTING is a novel, differentiated therapeutic candidate that leverages the natural biology of EVs to enhance the activity of CDNs.
Subject(s)
Extracellular Vesicles/physiology , Immunologic Surveillance , Tumor Microenvironment/physiology , Animals , Female , Mice , Mice, Inbred BALB C , Mice, Inbred C57BLABSTRACT
Prodrugs engineered for preferential activation in diseased versus normal tissues offer immense potential to improve the therapeutic indexes (TIs) of preclinical and clinical-stage active pharmaceutical ingredients that either cannot be developed otherwise or whose efficacy or tolerability it is highly desirable to improve. Such approaches, however, often suffer from trial-and-error design, precluding predictive synthesis and optimization. Here, using bromodomain and extra-terminal (BET) protein inhibitors (BETi)-a class of epigenetic regulators with proven anticancer potential but clinical development hindered in large part by narrow TIs-we introduce a macromolecular prodrug platform that overcomes these challenges. Through tuning of traceless linkers appended to a "bottlebrush prodrug" scaffold, we demonstrate correlation of in vitro prodrug activation kinetics with in vivo tumor pharmacokinetics, enabling the predictive design of novel BETi prodrugs with enhanced antitumor efficacies and devoid of dose-limiting toxicities in a syngeneic triple-negative breast cancer murine model. This work may have immediate clinical implications, introducing a platform for predictive prodrug design and potentially overcoming hurdles in drug development.
Subject(s)
Antineoplastic Agents/pharmacology , Drug Design , Prodrugs/pharmacology , Proteins/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , Drug Screening Assays, Antitumor , Humans , Macromolecular Substances/chemical synthesis , Macromolecular Substances/chemistry , Macromolecular Substances/pharmacology , Mammary Neoplasms, Experimental/drug therapy , Mammary Neoplasms, Experimental/metabolism , Mammary Neoplasms, Experimental/pathology , Mice , Molecular Structure , Prodrugs/chemical synthesis , Prodrugs/chemistry , Proteins/metabolismABSTRACT
c-Met is a transmembrane tyrosine kinase that mediates activation of several signaling pathways implicated in aggressive cancer phenotypes. In recent years, research into this area has highlighted c-Met as an attractive cancer drug target, triggering a number of approaches to disrupt aberrant c-Met signaling. Screening efforts identified a unique class of 5H-benzo[4,5]cyclohepta[1,2-b]pyridin-5-one kinase inhibitors, exemplified by 1. Subsequent SAR studies led to the development of 81 (MK-2461), a potent inhibitor of c-Met that was efficacious in preclinical animal models of tumor suppression. In addition, biochemical studies and X-ray analysis have revealed that this unique class of kinase inhibitors binds preferentially to the activated (phosphorylated) form of the kinase. This report details the development of 81 and provides a description of its unique biochemical properties.
Subject(s)
Antineoplastic Agents/chemical synthesis , Benzocycloheptenes/chemical synthesis , Pyridines/chemical synthesis , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Benzocycloheptenes/pharmacokinetics , Benzocycloheptenes/pharmacology , Cell Line, Tumor , Crystallography, X-Ray , Dogs , Drug Screening Assays, Antitumor , Female , Haplorhini , Humans , Mice , Mice, Nude , Models, Molecular , Mutation , Neoplasm Transplantation , Phosphorylation , Protein Binding , Pyrazoles/chemical synthesis , Pyrazoles/pharmacokinetics , Pyrazoles/pharmacology , Pyridines/pharmacokinetics , Pyridines/pharmacology , Rats , Receptor Protein-Tyrosine Kinases/genetics , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Sulfonamides/pharmacokinetics , Sulfonamides/pharmacology , Transplantation, HeterologousABSTRACT
We report the preparation and structure-activity relationships of phosphorus-containing histone deacetylase inhibitors. A strong trend between decreasing phosphorus functional group size and superior mouse pharmacokinetic properties was identified. In addition, optimized candidates showed tumor growth inhibition in xenograft studies.
Subject(s)
Antineoplastic Agents/pharmacokinetics , Enzyme Inhibitors/pharmacokinetics , Histone Deacetylase Inhibitors , Organophosphonates/pharmacokinetics , Repressor Proteins/antagonists & inhibitors , Administration, Oral , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Histone Deacetylase 1 , Histone Deacetylase 2 , Histone Deacetylases/metabolism , Mice , Mice, Nude , Organophosphonates/chemical synthesis , Organophosphonates/chemistry , Repressor Proteins/metabolism , Transplantation, HeterologousABSTRACT
The successful application of both solid and solution phase library synthesis, combined with tight integration into the medicinal chemistry effort, resulted in the efficient optimization of a novel structural series of selective HDAC1/HDAC2 inhibitors by the MRL-Boston Parallel Medicinal Chemistry group. An initial lead from a small parallel library was found to be potent and selective in biochemical assays. Advanced compounds were the culmination of iterative library design and possess excellent biochemical and cellular potency, as well as acceptable PK and efficacy in animal models.
Subject(s)
Histone Deacetylase Inhibitors , Animals , Combinatorial Chemistry Techniques , Dogs , Drug Design , Histone Deacetylase 1 , Histone Deacetylase 2 , Humans , Molecular Structure , Rats , Repressor Proteins/antagonists & inhibitors , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
A potent family of spirocyclic nicotinyl aminobenzamide selective HDAC1/HDAC2 inhibitors (SHI-1:2) is profiled. The incorporation of a biaryl zinc-binding motif into a nicotinyl scaffold resulted in enhanced potency and selectivity versus HDAC3, but also imparted hERG activity. It was discovered that increasing polar surface area about the spirocycle attenuates this liability. Compound 12 induced a 4-fold increase in acetylated histone H2B in an HCT-116 xenograft model study with acute exposure, and inhibited tumor growth in a 21-day efficacy study with qd dosing.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Ether-A-Go-Go Potassium Channels/metabolism , Histone Deacetylase Inhibitors , Niacinamide/chemical synthesis , Niacinamide/pharmacology , Spiro Compounds/chemical synthesis , Spiro Compounds/pharmacology , Animals , Antineoplastic Agents/chemistry , Benzamides/chemical synthesis , Benzamides/chemistry , Benzamides/pharmacology , Combinatorial Chemistry Techniques , ERG1 Potassium Channel , Ether-A-Go-Go Potassium Channels/drug effects , HCT116 Cells , Histone Deacetylases , Histones/analysis , Humans , Mice , Mice, Nude , Molecular Structure , Niacinamide/chemistry , Protein Isoforms , Spiro Compounds/chemistry , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
An HTS screening campaign identified a series of low molecular weight phenols that showed excellent selectivity (>100-fold) for HDAC1/HDAC2 over other Class I and Class II HDACs. Evolution and optimization of this HTS hit series provided HDAC1-selective (SHI-1) compounds with excellent anti-proliferative activity and improved physical properties. Dose-dependent efficacy in a mouse HCT116 xenograft model was demonstrated with a phenylglycine SHI-1 analog.
Subject(s)
Cell Proliferation/drug effects , Colonic Neoplasms/drug therapy , Enzyme Inhibitors/pharmacology , Glycine/analogs & derivatives , Histone Deacetylase Inhibitors , Phenylalanine/chemistry , Acetylation , Amides , Animals , Colonic Neoplasms/enzymology , Colonic Neoplasms/pathology , Dogs , ERG1 Potassium Channel , Enzyme Inhibitors/pharmacokinetics , Ether-A-Go-Go Potassium Channels/metabolism , Glycine/chemistry , Histone Deacetylase 1 , Humans , Macaca mulatta , Mice , Molecular Structure , Structure-Activity Relationship , Tumor Cells, Cultured , Xenograft Model Antitumor AssaysABSTRACT
We report herein the initial exploration of novel selective HDAC1/HDAC2 inhibitors (SHI-1:2). Optimized SHI-1:2 structures exhibit enhanced intrinsic activity against HDAC1 and HDAC2, and are greater than 100-fold selective versus other HDACs, including HDAC3. Based on the SAR of these agents and our current understanding of the HDAC active site, we postulate that the SHI-1:2 extend the existing HDAC inhibitor pharmacophore to include an internal binding domain.
Subject(s)
Benzene Derivatives/chemical synthesis , Benzene Derivatives/pharmacology , Histone Deacetylase Inhibitors , Models, Molecular , Benzene Derivatives/chemistry , Binding Sites/drug effects , Histone Deacetylase 1 , Histone Deacetylase 2 , Histone Deacetylases/chemistry , Histone Deacetylases/metabolism , Humans , Molecular Structure , Protein Isoforms , Repressor Proteins , Structure-Activity RelationshipABSTRACT
Ongoing clinical studies indicate that inhibitors of Class I and Class II histone deacetylase (HDAC) enzymes show great promise for the treatment of cancer. Zolinza (SAHA, Zolinza) was recently approved by the FDA for the treatment of the cutaneous manifestations of cutaneous T-cell lymphoma. As a part of an ongoing effort to identify novel small molecules to target these important enzymes, we have prepared several classes of amino acid-derived HDAC1 inhibitors. The design rationale and in vitro activity against the HDAC1 enzyme and HCT116 cell line are described in this letter.
Subject(s)
Amino Acids/chemistry , Amino Acids/pharmacology , Histone Deacetylase Inhibitors , Amino Acids/chemical synthesis , Drug Screening Assays, Antitumor , HCT116 Cells , Histone Deacetylase 1 , Humans , Piperazines/chemical synthesis , Piperazines/chemistry , Piperazines/pharmacology , Structure-Activity Relationship , Thiophenes/chemical synthesis , Thiophenes/chemistry , Thiophenes/pharmacologyABSTRACT
This communication highlights the development of a nicotinamide series of histone deacetylase inhibitors within the benzamide structural class. Extensive exploration around the nicotinamide core led to the discovery of a class I selective HDAC inhibitor that possesses excellent intrinsic and cell-based potency, acceptable ancillary pharmacology, favorable pharmacokinetics, sustained pharmacodynamics in vitro, and achieves in vivo efficacy in an HCT116 xenograft model.
Subject(s)
6-Aminonicotinamide/analogs & derivatives , 6-Aminonicotinamide/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Histone Deacetylase Inhibitors , 6-Aminonicotinamide/chemical synthesis , Animals , Area Under Curve , Benzamides/chemistry , Biological Availability , Cell Line, Tumor , Cell Membrane Permeability/drug effects , Dogs , Drug Design , Drug Screening Assays, Antitumor , Enzyme Inhibitors/pharmacokinetics , Half-Life , Humans , Isoenzymes/antagonists & inhibitors , Models, Molecular , Neoplasm Transplantation , Protein Binding , Rats , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Nijmegen breakage syndrome (NBS) is a rare autosomal recessive disorder. Originally thought to be a variant of ataxia telangiectasia (AT), the cellular phenotype of NBS has been described as almost indistinguishable from that of AT. Since the gene involved in NBS has been cloned and its functions studied, we sought to further characterize its cellular phenotype by examining the response of density-inhibited, confluent cultures of human diploid fibroblasts to irradiation in the G(0)/G(1) phase of the cell cycle. Both NBS and AT cells were markedly sensitive to the cytotoxic effects of radiation. NBS cells, however, were proficient in recovery from potentially lethal damage and exhibited a pronounced radiation-induced G(1)-phase arrest. Irradiated AT cells showed no potentially lethal damage and no G(1)-phase arrest. Both cell types were hypersensitive to the induction of chromosomal aberrations, whereas the distribution of aberrations in irradiated NBS cells was similar to that of normal controls, AT cells showed a high frequency of chromatid-type aberrations. TP53 and CDKN1A (also known as p21(Waf1)) expression was attenuated in irradiated NBS cells, but maximal induction occurred 2 h postirradiation, as was observed in normal controls. The similarities and differences in cellular phenotype between irradiated NBS and AT cells are discussed in terms of the functional properties of the signaling pathways downstream of AT involving the NBS1 and TP53 proteins.
Subject(s)
Ataxia Telangiectasia/pathology , Chromosome Breakage , Chromosome Fragility , Chromosomes, Human/radiation effects , Neoplastic Syndromes, Hereditary/pathology , Abnormalities, Multiple/genetics , Abnormalities, Multiple/pathology , Ataxia Telangiectasia Mutated Proteins , Cell Cycle Proteins/genetics , Cell Cycle Proteins/physiology , Cells, Cultured/radiation effects , Chromatids/radiation effects , DNA Damage , DNA Repair , DNA-Binding Proteins , Fibroblasts/chemistry , Fibroblasts/radiation effects , G1 Phase/radiation effects , Humans , Immunologic Deficiency Syndromes/genetics , Immunologic Deficiency Syndromes/pathology , Nuclear Proteins/deficiency , Nuclear Proteins/genetics , Nuclear Proteins/physiology , Protein Serine-Threonine Kinases/deficiency , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/physiology , Resting Phase, Cell Cycle/radiation effects , Signal Transduction , Syndrome , Tumor Suppressor Protein p53/physiology , Tumor Suppressor ProteinsABSTRACT
The response to ionizing radiation was examined in diploid skin fibroblasts derived from 5 patients with hereditary type retinoblastoma as well as their parents. Unexpected sensitivity to cell killing, as measured by clonogenic survival, as well as enhanced radiation-induced G(1) arrest were observed in at least 1 parental fibroblast strain in all 5 families. In all cases, parental strains were equally or more radiosensitive than the probands. The mutation of the retinoblastoma gene (RB) determined in 4 of 5 probands was either absent from the parental cells, as expected from the negative family histories, or identical, in 1 father who was a known carrier. In the fifth family, the family history was negative for retinoblastoma. We hypothesize that the increased parental cell sensitivity to radiation suggests the presence of an as yet unrecognized genetic event occurring in 1 or both parents of children with retinoblastoma. Whether it increases mutability of the RB locus or other loci or interacts with RB is conjectural.
