Discovery of a Small-Molecule Inhibitor of Protein-MicroRNA Interaction Using Binding Assay with a Site-Specifically Labeled Lin28.
MicroRNAs (miRNAs) regulate gene expression by targeting protein-coding transcripts that are involved in various cellular processes. Thus, miRNA biogenesis has been recognized as a novel therapeutic target. Especially, the let-7 miRNA family is well-known for its tumor suppressor functions and is downregulated in many cancer cells. Lin28 protein binds to let-7 miRNA precursors to inhibit their maturation. Herein, we developed a FRET-based, high-throughput screening system to identify small-molecule inhibitors of the Lin28-let-7 interaction. We employed unnatural amino acid mutagenesis and bioorthogonal chemistry for the site-specific fluorescent labeling of Lin28, which ensures the robustness and reliability of the FRET-based protein-miRNA binding assay. Using this direct binding assay, we identified an inhibitor of the oncogenic Lin28-let-7 interaction. The inhibitor enhanced the production of let-7 miRNAs in Lin28-expressing cancer cells and reduced the level of let-7 target oncogene products.
Department of Biophysics and Chemical Biology, Seoul National University , Seoul 08826, Korea.
Donghyun
D
Lim
CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University , Seoul 08826, Korea.
Wan Gi
WG
Byun
CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University , Seoul 08826, Korea.
Ja Young
JY
Koo
Department of Biophysics and Chemical Biology, Seoul National University , Seoul 08826, Korea.
Hankum
H
Park
Department of Biophysics and Chemical Biology, Seoul National University , Seoul 08826, Korea.|CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University , Seoul 08826, Korea.
Seung Bum
SB
Park