title: Structural insights into inhibition of the bivalent menin-MLL interaction by small molecules in leukemia.
abstract: Menin functions as a critical oncogenic cofactor of mixed lineage leukemia (MLL) fusion proteins in the development of acute leukemias, and inhibition of the menin interaction with MLL fusion proteins represents a very promising strategy to reverse their oncogenic activity. MLL interacts with menin in a bivalent mode involving 2 N-terminal fragments of MLL. In the present study, we reveal the first high-resolution crystal structure of human menin in complex with a small-molecule inhibitor of the menin-MLL interaction, MI-2. The structure shows that the compound binds to the MLL pocket in menin and mimics the key interactions of MLL with menin. Based on the menin-MI-2 structure, we developed MI-2-2, a compound that binds to menin with low nanomolar affinity (K(d) = 22nM) and very effectively disrupts the bivalent protein-protein interaction between menin and MLL. MI-2-2 demonstrated specific and very pronounced activity in MLL leukemia cells, including inhibition of cell proliferation, down-regulation of Hoxa9 expression, and differentiation. Our results provide the rational and essential structural basis to design next generation of inhibitors for effective targeting of the menin-MLL interaction in leukemia and demonstrate a proof of concept that inhibition of complex multivalent protein-protein interactions can be achieved by a small-molecule inhibitor.
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Aibin
authors.initials: A
authors.lastname: Shi
authors.forename: Marcelo J
authors.initials: MJ
authors.lastname: Murai
authors.forename: Shihan
authors.initials: S
authors.lastname: He
authors.forename: George
authors.initials: G
authors.lastname: Lund
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartley
authors.forename: Trupta
authors.initials: T
authors.lastname: Purohit
authors.forename: Gireesh
authors.initials: G
authors.lastname: Reddy
authors.forename: Maksymilian
authors.initials: M
authors.lastname: Chruszcz
authors.forename: Jolanta
authors.initials: J
authors.lastname: Grembecka
authors.forename: Tomasz
authors.initials: T
authors.lastname: Cierpicki
mesh_terms: D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D057809:HEK293 Cells; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D007938:Leukemia / Q000188:drug therapy* / Q000473:pathology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D051788:Myeloid-Lymphoid Leukemia Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C497422:KMT2A protein, human; C105373:MEN1 protein, human; D011518:Proto-Oncogene Proteins; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase