Small-Molecule Inhibitors Disrupt let-7 Oligouridylation and Release the Selective Blockade of let-7 Processing by LIN28.
Longfei Wang, R Grant Rowe, Adriana Jaimes, Chunxiao Yu, Yunsun Nam, Daniel S Pearson, Jin Zhang, Xiangyu Xie, William Marion, Gregory J Heffron, George Q Daley, Piotr Sliz
Author Information
Longfei Wang: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
R Grant Rowe: Stem Cell Program, Boston Children's Hospital, Boston, MA, USA; Department of Pediatric Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Boston, MA, USA.
Adriana Jaimes: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
Chunxiao Yu: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
Yunsun Nam: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
Daniel S Pearson: Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.
Jin Zhang: Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.
Xiangyu Xie: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
William Marion: Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.
Gregory J Heffron: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
George Q Daley: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Stem Cell Program, Boston Children's Hospital, Boston, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, USA; Howard Hughes Medical Institute, Boston, MA, USA; Division of Hematology, Brigham and Women's Hospital, Boston, MA, USA; Manton Center for Orphan Disease Research, Boston, MA, USA.
Piotr Sliz: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA. Electronic address: sliz@hkl.hms.harvard.edu.
LIN28 is an RNA-binding protein that regulates the maturation of the let-7 family of microRNAs by bipartite interactions with let-7 precursors through its two distinct cold shock and zinc-knuckle domains. Through inhibition of let-7 biogenesis, LIN28 functions as a pluripotency factor, as well as a driver of tumorigenesis. Here, we report a fluorescence polarization assay to identify small-molecule inhibitors for both domains of LIN28 involved in let-7 interactions. Of 101,017 compounds screened, six inhibit LIN28:let-7 binding and impair LIN28-mediated let-7 oligouridylation. Upon further characterization, we demonstrate that the LIN28 inhibitor TPEN destabilizes the zinc-knuckle domain of LIN28, while LI71 binds the cold shock domain to suppress LIN28's activity against let-7 in leukemia cells and embryonic stem cells. Our results demonstrate selective pharmacologic inhibition of individual domains of LIN28 and provide a foundation for therapeutic inhibition of the let-7 biogenesis pathway in LIN28-driven diseases.
