TY - JOUR
T1 - Loss of the histone methyltransferase EZH2 induces resistance to multiple drugs in acute myeloid leukemia
AU - Göllner, Stefanie
AU - Oellerich, Thomas
AU - Agrawal-Singh, Shuchi
AU - Schenk, Tino
AU - Klein, Hans-Ulrich
AU - Rohde, Christian
AU - Pabst, Caroline
AU - Sauer, Tim
AU - Lerdrup, Mads
AU - Tavor, Sigal
AU - Stölzel, Friedrich
AU - Herold, Sylvia
AU - Ehninger, Gerhard
AU - Köhler, Gabriele
AU - Pan, Kuan-Ting
AU - Urlaub, Henning
AU - Serve, Hubert
AU - Dugas, Martin
AU - Spiekermann, Karsten
AU - Vick, Binje
AU - Jeremias, Irmela
AU - Berdel, Wolfgang E
AU - Hansen, Klaus
AU - Zelent, Arthur
AU - Wickenhauser, Claudia
AU - Müller, Lutz P
AU - Thiede, Christian
AU - Müller-Tidow, Carsten
PY - 2017/1/1
Y1 - 2017/1/1
N2 - In acute myeloid leukemia (AML), therapy resistance frequently occurs, leading to high mortality among patients. However, the mechanisms that render leukemic cells drug resistant remain largely undefined. Here, we identified loss of the histone methyltransferase EZH2 and subsequent reduction of histone H3K27 trimethylation as a novel pathway of acquired resistance to tyrosine kinase inhibitors (TKIs) and cytotoxic drugs in AML. Low EZH2 protein levels correlated with poor prognosis in AML patients. Suppression of EZH2 protein expression induced chemoresistance of AML cell lines and primary cells in vitro and in vivo. Low EZH2 levels resulted in derepression of HOX genes, and knockdown of HOXB7 and HOXA9 in the resistant cells was sufficient to improve sensitivity to TKIs and cytotoxic drugs. The endogenous loss of EZH2 expression in resistant cells and primary blasts from a subset of relapsed AML patients resulted from enhanced CDK1-dependent phosphorylation of EZH2 at Thr487. This interaction was stabilized by heat shock protein 90 (HSP90) and followed by proteasomal degradation of EZH2 in drug-resistant cells. Accordingly, inhibitors of HSP90, CDK1 and the proteasome prevented EZH2 degradation, decreased HOX gene expression and restored drug sensitivity. Finally, patients with reduced EZH2 levels at progression to standard therapy responded to the combination of bortezomib and cytarabine, concomitant with the re-establishment of EZH2 expression and blast clearance. These data suggest restoration of EZH2 protein as a viable approach to overcome treatment resistance in this AML patient population.
AB - In acute myeloid leukemia (AML), therapy resistance frequently occurs, leading to high mortality among patients. However, the mechanisms that render leukemic cells drug resistant remain largely undefined. Here, we identified loss of the histone methyltransferase EZH2 and subsequent reduction of histone H3K27 trimethylation as a novel pathway of acquired resistance to tyrosine kinase inhibitors (TKIs) and cytotoxic drugs in AML. Low EZH2 protein levels correlated with poor prognosis in AML patients. Suppression of EZH2 protein expression induced chemoresistance of AML cell lines and primary cells in vitro and in vivo. Low EZH2 levels resulted in derepression of HOX genes, and knockdown of HOXB7 and HOXA9 in the resistant cells was sufficient to improve sensitivity to TKIs and cytotoxic drugs. The endogenous loss of EZH2 expression in resistant cells and primary blasts from a subset of relapsed AML patients resulted from enhanced CDK1-dependent phosphorylation of EZH2 at Thr487. This interaction was stabilized by heat shock protein 90 (HSP90) and followed by proteasomal degradation of EZH2 in drug-resistant cells. Accordingly, inhibitors of HSP90, CDK1 and the proteasome prevented EZH2 degradation, decreased HOX gene expression and restored drug sensitivity. Finally, patients with reduced EZH2 levels at progression to standard therapy responded to the combination of bortezomib and cytarabine, concomitant with the re-establishment of EZH2 expression and blast clearance. These data suggest restoration of EZH2 protein as a viable approach to overcome treatment resistance in this AML patient population.
U2 - 10.1038/nm.4247
DO - 10.1038/nm.4247
M3 - Journal article
C2 - 27941792
SN - 1078-8956
VL - 23
SP - 69
EP - 78
JO - Nature Medicine
JF - Nature Medicine
IS - 1
ER -