The Laboratory of Chromatin
Biology and Cancer Epigenetics

A Molecular Switch Between Mammalian MLL Complexes Dictates Response to Menin-MLL Inhibition

Yadira M Soto-Feliciano, Francisco J Sanchez-Rivera, Florian Perner, Douglas W Barrows, Edward R Kastenhuber, Yu-Jui Ho, Thomas Carroll, Yijun Xiong, Disha Anand, Alexey A Soshnev, Leah Gates, Mary Clare Beytagh, David Cheon, Shengqing Gu, X Shirley Liu, Andrei V Krivtsov, Maximiliano Meneses, Elisa de Stanchine, Richard M Stone, Scott A Armstrong, Scott W Lowe, C David Allis

Cancer Discovery, Jan 09, 2023

Menin interacts with oncogenic MLL1-fusion proteins, and small molecules that disrupt these associations are in clinical trials for leukemia treatment. By integrating chromatin-focused and genome-wide CRISPR screens with genetic, pharmacologic, and biochemical approaches, we discovered a conserved molecular switch between the MLL1-Menin and MLL3/4-UTX chromatin-modifying complexes that dictates response to Menin-MLL inhibitors. MLL1-Menin safeguards leukemia survival by impeding the binding of the MLL3/4-UTX complex at a subset of target gene promoters. Disrupting the Menin-MLL1 interaction triggers UTX-dependent transcriptional activation of a tumor-suppressive program that dictates therapeutic responses in murine and human leukemia. Therapeutic reactivation of this program using CDK4/6 inhibitors mitigates treatment resistance in leukemia cells that are insensitive to Menin inhibitors. These findings shed light on novel functions of evolutionarily conserved epigenetic mediators like MLL1-Menin and MLL3/4-UTX and are relevant to understand and target molecular pathways determining therapeutic responses in ongoing clinical trials.

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