TOX regulates growth, DNA repair, and genomic instability in T-cell acute lymphoblastic leukemia

Riadh Lobbardi, Jordan Pinder, Barbara Martinez-Pastor, Marina Theodorou, Jessica S. Blackburn, Brian J. Abraham, Yuka Namiki, Marc Mansour, Nouran S. Abdelfattah, Aleksey Molodtsov, Gabriela Alexe, Debra Toiber, Manon De Waard, Esha Jain, Myriam Boukhali, Mattia Lion, Deepak Bhere, Khalid Shah, Alejandro Gutierrez, Kimberly StegmaierLewis B. Silverman, Ruslan I. Sadreyev, John M. Asara, Marjorie A. Oettinger, Wilhelm Haas, A. Thomas Look, Richard A. Young, Raul Mostoslavsky, Graham Dellaire, David M. Langenau

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of thy-mocytes. Using a transgenic screen in zebrafish, thymocyte selection–associated high mobility group box protein (TOX) was uncovered as a collaborating oncogenic driver that accelerated T-ALL onset by expanding the initiating pool of transformed clones and elevating genomic instability. TOX is highly expressed in a majority of human T-ALL and is required for proliferation and continued xenograft growth in mice. Using a wide array of functional analyses, we uncovered that TOX binds directly to KU70/80 and suppresses recruitment of this complex to DNA breaks to inhibit non-homologous end joining (NHEJ) repair. Impaired NHEJ is well known to cause genomic instability, including development of T-cell malignancies in KU70- and KU80-deficient mice. Collectively, our work has uncovered important roles for TOX in regulating NHEJ by elevating genomic instability during leukemia initiation and sustaining leukemic cell proliferation following transformation. SIGNIFICANCE: TOX is an HMG box–containing protein that has important roles in T-ALL initiation and maintenance. TOX inhibits the recruitment of KU70/KU80 to DNA breaks, thereby inhibiting NHEJ repair. Thus, TOX is likely a dominant oncogenic driver in a large fraction of human T-ALL and enhances genomic instability.

Original languageEnglish
Pages (from-to)1336-1353
Number of pages18
JournalCancer Discovery
Volume7
Issue number11
DOIs
StatePublished - 1 Nov 2017

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