Data from Oncogenic Deregulation of EZH2 as an Opportunity for Targeted Therapy in Lung Cancer

Abstract

<div>Abstract<p>As a master regulator of chromatin function, the lysine methyltransferase EZH2 orchestrates transcriptional silencing of developmental gene networks. Overexpression of <i>EZH2</i> is commonly observed in human epithelial cancers, such as non–small cell lung carcinoma (NSCLC), yet definitive demonstration of malignant transformation by deregulated <i>EZH2</i> remains elusive. Here, we demonstrate the causal role of <i>EZH2</i> overexpression in NSCLC with new genetically engineered mouse models of lung adenocarcinoma. Deregulated <i>EZH2</i> silences normal developmental pathways, leading to epigenetic transformation independent of canonical growth factor pathway activation. As such, tumors feature a transcriptional program distinct from <i>KRAS</i>- and <i>EGFR</i>-mutant mouse lung cancers, but shared with human lung adenocarcinomas exhibiting high EZH2 expression. To target EZH2-dependent cancers, we developed a potent open-source EZH2 inhibitor, JQEZ5, that promoted the regression of EZH2-driven tumors <i>in vivo</i>, confirming oncogenic addiction to EZH2 in established tumors and providing the rationale for epigenetic therapy in a subset of lung cancer.</p><p><b>Significance:</b> <i>EZH2</i> overexpression induces murine lung cancers that are similar to human NSCLC with high EZH2 expression and low levels of phosphorylated AKT and ERK, implicating biomarkers for EZH2 inhibitor sensitivity. Our EZH2 inhibitor, JQEZ5, promotes regression of these tumors, revealing a potential role for anti-EZH2 therapy in lung cancer. <i>Cancer Discov; 6(9); 1006–21. ©2016 AACR.</i></p><p><i>See related commentary by Frankel et al., p. 949</i>.</p><p>This article is highlighted in the In This Issue feature, p. 932</p></div>