Inhibitors of human ezh2, and methods of use thereof

Abstract

The invention relates to inhibition of wild-type and certain mutant forms of human histone methyltransferase EZH2, the catalytic subunit of the PRC2 complex which catalyzes the mono- through tri-methylation of lysine 27 on histone H3 (H3-K27). In one embodiment the inhibition is selective for the mutant form of the EZH2, such that trimethylation of H3-K27, which is associated with certain cancers, is inhibited. The methods can be used to treat cancers including follicular lymphoma and diffuse large B-cell lymphoma (DLBCL). Also provided are methods for identifying small molecule selective inhibitors of the mutant forms of EZH2 and also methods for determining responsiveness to an EZH2 inhibitor in a subject.

1 - 28 . (canceled) 
     
     
         29 . A method of inhibiting EZH2, the method comprising contacting a cell expressing a mutant of EZH2 comprising a mutation at amino acid position 677, 687, 674, 685, or 641 with an inhibitor of EZH2 in an amount effective to inhibit the conversion of H3-K27 to trimethylated H3-K27 in the cell. 
     
     
         30 . The method of  claim 29 , wherein the mutant EZH2 comprises a substitution of glycine (G) for the wild type residue alanine (A) at amino acid position 677 (A677G). 
     
     
         31 . The method of  claim 29 , wherein the mutant EZH2 comprises a substitution of valine (V) for the wild type residue alanine (A) at amino acid position 687 (A687V). 
     
     
         32 . The method of  claim 29 , wherein the mutant EZH2 comprises a substitution of methionine (M) for the wild type residue valine (V) at amino acid position 674 (V674M). 
     
     
         33 . The method of  claim 29 , wherein the mutant EZH2 comprises a substitution of histidine (H) or cysteine (C) for the wild type residue arginine (R) at amino acid position 685 (R685H or R685C). 
     
     
         34 . The method of  claim 29 , wherein the mutant EZH2 comprises a substitution of phenylalanine (F), histidine (H), asparagine (N), serine (S), or cysteine (C) for the wild type residue tyrosine (Y) at amino acid position 641. 
     
     
         35 . The method of  claim 29 , wherein the EZH2 inhibitor is a compound of Table 1, or a pharmaceutically acceptable salt thereof. 
     
     
         36 . The method of  claim 29 , wherein the EZH2 inhibitor is 
       
         
           
           
               
               
           
         
       
     
     
         37 . The method of  claim 29 , wherein the cell expressing the mutant of EZH2 is a cancer cell. 
     
     
         38 . The method of  claim 37 , wherein the cancer is lymphoma, leukemia, or melanoma. 
     
     
         39 . The method of  claim 38 , wherein the lymphoma is non-Hodgkin lymphoma, follicular lymphoma, or diffuse large B-cell lymphoma. 
     
     
         40 . The method of  claim 38 , wherein the leukemia is chronic myelogenous leukemia (CML). 
     
     
         41 . The method of  claim 37 , wherein the cancer is the precancerous condition myelodysplastic syndrome (MDS, formerly known as preleukemia). 
     
     
         42 . The method of  claim 38 , wherein the cancer is a melanoma. 
     
     
         43 . The method of  claim 29 , wherein the cell expressing the mutant of EZH2 is a cell obtained from a subject. 
     
     
         44 . The method of  claim 29 , wherein the method further comprises obtaining the cell expressing the mutant of EZH2 from a subject. 
     
     
         45 . The method of  claim 29 , wherein the cell expressing the mutant of EZH2 is a cell of a subject having cancer. 
     
     
         46 . The method of  claim 45 , wherein the subject is a human subject. 
     
     
         47 . The method of  claim 45 , wherein the contacting comprises administering the EZH2 inhibitor to the subject.