Core binding factor fusion downregulation of ADAR2 RNA editing contributes to AML leukemogenesis
Mingrui Guo, Hon Man Tim Chan, Qiling Zhou, Ömer An, Ying Li, Yangyang Song, Zi Hui Tan, Hui En Vanessa Ng, Philomina Sona Peramangalam, Zhi Qing Tan, Xinang Cao, Eisaku Iwanaga, Masao Matsuoka, Melissa Ooi, Wei‐Ying Jen, Liang Piu Koh, Esther W. Chan, Lip Kun Tan, Yufen Goh, Wilson Wang, Bryan T. H. Koh, Ming Chun Chan, Melissa J. Fullwood, Wee Joo Chng, Motomi Osato, John Anto Pulikkan, Henry Yang, Leilei Chen, Daniel G. Tenen
Abstract
Adenosine-to-inosine RNA editing, which is catalyzed by adenosine deaminases acting on RNA (ADAR) family of enzymes, ADAR1 and ADAR2, has been shown to contribute to multiple cancers. However, other than the chronic myeloid leukemia blast crisis, relatively little is known about its role in other types of hematological malignancies. Here, we found that ADAR2, but not ADAR1 and ADAR3, was specifically downregulated in the core-binding factor (CBF) acute myeloid leukemia (AML) with t(8;21) or inv(16) translocations. In t(8;21) AML, RUNX1-driven transcription of ADAR2 was repressed by the RUNX1-ETO additional exon 9a fusion protein in a dominant-negative manner. Further functional studies confirmed that ADAR2 could suppress leukemogenesis specifically in t(8;21) and inv16 AML cells dependent on its RNA editing capability. Expression of 2 exemplary ADAR2-regulated RNA editing targets coatomer subunit α and component of oligomeric Golgi complex 3 inhibits the clonogenic growth of human t(8;21) AML cells. Our findings support a hitherto, unappreciated mechanism leading to ADAR2 dysregulation in CBF AML and highlight the functional relevance of loss of ADAR2-mediated RNA editing to CBF AML.