Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
ACS Med Chem Lett ; 12(6): 878-886, 2021 Jun 10.
Article in English | MEDLINE | ID: mdl-34141065

ABSTRACT

MicroRNAs (miRNAs) are a family of small noncoding RNAs that regulate gene expression. Due to their important activity in the fine-tuning of protein translation, abnormal expression of miRNAs has been linked to many human diseases, making the targeting of miRNAs attractive as a novel therapeutic strategy. Accordingly, researchers have been heavily engaged in the discovery of small molecule modulators of miRNAs. With an interest in the identification of new chemical space for targeting miRNAs, we developed a high-throughput screening (HTS) technology, catalytic enzyme-linked click chemistry assay (cat-ELCCA), aimed at the discovery of small molecule ligands for pre-miR-21, a miRNA that is frequently overexpressed in human cancers. From our HTS campaign, we found that natural products, a source of many impactful human medicines, may be a promising source of potential pre-miR-21-selective maturation inhibitors. Herein we describe our first efforts in natural product inhibitor discovery leading to the identification of a depsipeptide class of natural products as RNA-binding inhibitors of Dicer-mediated miRNA processing.

2.
Eur J Med Chem ; 205: 112655, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-32739551

ABSTRACT

Eukaryotic translation initiation factor 4E (eIF4E) has emerged as a promising cancer therapeutic target due to its role in the initiation of cap-dependent translation, a process that is accelerated during tumorigenesis. To regulate the initiation of cap-dependent translation, eIF4E participates in protein-protein interactions (PPI) with binding partners, 4E-BP1 and eIF4G, which act as an inhibitor and stimulator of translation, respectively. As both of these proteins interact with eIF4E by utilizing a short, α-helical stretch of amino acids, our laboratory has been working to develop helical mimetics of these proteins, in particular 4E-BP1, to inhibit eIF4E PPIs. Herein, we describe our continued efforts in this area and report the development and characterization of a cell-penetrant lactam stapled peptide for targeting cellular eIF4E.


Subject(s)
Cell-Penetrating Peptides/chemistry , Cell-Penetrating Peptides/pharmacology , Eukaryotic Initiation Factor-4E/metabolism , Lactams/chemistry , Cell Line, Tumor , Humans , Molecular Targeted Therapy , Protein Binding/drug effects , Protein Biosynthesis
3.
Org Biomol Chem ; 17(26): 6414-6419, 2019 07 14.
Article in English | MEDLINE | ID: mdl-31215581

ABSTRACT

Hydrocarbon stapled (HCS) peptides are a class of cross-linked α-helix mimetics. The technology relies on the use of α,α'-disubstituted alkenyl amino acids, which fully contrain the helical region to typically yield peptides with enhanced structural ordering and biological activity. Recently, monosubstituted alkenyl amino acids were disclosed for peptide stapling; however, the impact that this tether has on HCS peptide structure and activity has not yet been fully explored. By applying this HCS to the disordered peptide eIF4E-binding protein 1 (4E-BP1), we discovered that this type of tethering has a dramatic effect on olefin geometry and activity of the resultant stapled peptides, where the putative trans isomer was found to exhibit enhanced in vitro and cellular inhibitory activity against eIF4E protein-protein interactions. We further demonstrated that the metathesis catalyst used for ring-closing metathesis can influence monosubstituted HCS peptide activity, presumably through alteration of the cis/trans olefin ratio. This study represents one of the first in-depth analyses of olefin isomers of a stapled peptide and highlights an additional feature for medicinal chemistry optimization of this class of peptide-based probes.


Subject(s)
Adaptor Proteins, Signal Transducing/chemistry , Alkenes/chemistry , Cell Cycle Proteins/chemistry , Peptides/chemistry , Humans , Models, Molecular , Peptides/chemical synthesis , Substrate Specificity
4.
Methods Enzymol ; 623: 85-99, 2019.
Article in English | MEDLINE | ID: mdl-31239059

ABSTRACT

Despite the great diversity of structure and function and relevance to human health, RNA remains an underexploited area of drug discovery. A major bottleneck toward this goal has been the identification of probes and drug leads that are specific for select RNAs and methods that will facilitate such discovery efforts. Our laboratory has recently developed an innovative approach for assaying RNA-small molecule interactions, catalytic enzyme-linked click chemistry assay or cat-ELCCA, which is a functional assay that takes advantage of the power of catalytic signal amplification combined with the selectivity and bioorthogonality of click chemistry. Importantly, through application of this platform assay technology to the challenging problem of identifying selective inhibitors of pre-microRNA maturation, we identified natural products as a potential source of such compounds. Herein we describe this methodology in addition to the downstream pipeline toward the discovery of natural product ligands for pre-microRNAs. Through cat-ELCCA, our goal is to discover novel ligands to facilitate our investigation of RNA recognition by small molecules.


Subject(s)
Biological Products/pharmacology , Click Chemistry/methods , Drug Discovery/methods , MicroRNAs/metabolism , Small Molecule Libraries/pharmacology , Biological Products/chemistry , High-Throughput Screening Assays/methods , Humans , Ligands , MicroRNAs/chemistry , Models, Molecular , Small Molecule Libraries/chemistry
5.
ACS Med Chem Lett ; 10(5): 816-821, 2019 May 09.
Article in English | MEDLINE | ID: mdl-31098005

ABSTRACT

In a high-throughput screening campaign, we recently discovered the rRNA-binding tetracyclines, methacycline and meclocycline, as inhibitors of Dicer-mediated processing of microRNAs. Herein, we describe our biophysical and biochemical characterization of these compounds. Interestingly, although direct, albeit weak, binding to the pre-microRNA hairpins was observed, the inhibitory activity of these compounds was not due to RNA binding. Through additional biochemical and chemical studies, we revealed that metal chelation likely plays a principle role in their mechanism of inhibition. By exploring the activity of other known RNA-binding scaffolds, we identified additional disconnections between direct RNA interaction and inhibition of Dicer processing. Thus, the results presented within provide a valuable case study in the complexities of targeting RNA with small molecules, particularly with weak binding and potentially promiscuous scaffolds.

6.
J Med Chem ; 62(10): 4967-4978, 2019 05 23.
Article in English | MEDLINE | ID: mdl-31033289

ABSTRACT

Protein disorder plays a crucial role in signal transduction and is key for many cellular processes including transcription, translation, and cell cycle. Within the intrinsically disordered protein interactome, the α-helix is commonly used for binding, which is induced via a disorder-to-order transition. Because the targeting of protein-protein interactions (PPIs) remains an important challenge in medicinal chemistry, efforts have been made to mimic this secondary structure for rational inhibitor design through the use of stapled peptides. Cap-dependent mRNA translation is regulated by two disordered proteins, 4E-BP1 and eIF4G, that inhibit or stimulate the activity of the m7G cap-binding translation initiation factor, eIF4E, respectively. Both use an α-helical motif for eIF4E binding, warranting the investigation of stapled peptide mimics for manipulating eIF4E PPIs. Herein, we describe our efforts toward this goal, resulting in the synthesis of a cell-active stapled peptide for further development in manipulating aberrant cap-dependent translation in human diseases.


Subject(s)
Adaptor Proteins, Signal Transducing/chemistry , Cell Cycle Proteins/chemistry , Drug Design , Eukaryotic Initiation Factor-4E/chemistry , Eukaryotic Initiation Factor-4G/chemistry , Peptide Fragments/chemical synthesis , Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/genetics , Amino Acid Sequence , Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Eukaryotic Initiation Factor-4E/antagonists & inhibitors , Eukaryotic Initiation Factor-4E/genetics , Eukaryotic Initiation Factor-4G/antagonists & inhibitors , Eukaryotic Initiation Factor-4G/genetics , Humans , Inhibitory Concentration 50 , Kinetics , Peptide Fragments/chemistry , Peptide Fragments/pharmacology , Plasmids , Protein Binding
7.
ACS Med Chem Lett ; 9(6): 517-521, 2018 Jun 14.
Article in English | MEDLINE | ID: mdl-29937975

ABSTRACT

Dysregulation of microRNA (miRNA) expression has been linked to many human diseases; however, because of the challenges associated with RNA-targeted drug discovery, additional approaches are needed for probing miRNA biology. The emerging regulatory role of miRNA-binding proteins in miRNA maturation presents such an alternative strategy. Exploiting our laboratory's click chemistry-based high-throughput screening (HTS) technology, catalytic enzyme-linked click chemistry assay or cat-ELCCA, we have designed a modular method by which to discover new chemical tools for manipulating pre-miRNA-miRNA-binding protein interactions. Using the pre-let-7d-Lin28 interaction as proof-of-concept, the results presented demonstrate how HTS using cat-ELCCA can enable the discovery of small molecules targeting RNA-protein interactions.

SELECTION OF CITATIONS
SEARCH DETAIL
...