An integrated approach to dissecting oncogene addiction implicates a Myb-coordinated self-renewal program as essential for leukemia maintenance

  1. Scott W. Lowe1,3,7,9
  1. 1Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
  2. 2Research Institute of Molecular Pathology (IMP), A-1030 Vienna, Austria;
  3. 3Watson School of Biological Sciences, Cold Spring Harbor, New York 11724, USA;
  4. 4Genetics Program, Stony Brook University, Stony Brook, New York 11794, USA;
  5. 5Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California at Los Angeles, California 90095, USA;
  6. 6Department of Laboratory Medicine, University of California at San Francisco, California 94143, USA;
  7. 7Howard Hughes Medical Institute, Cold Spring Harbor, New York 11724, USA
    1. 8 These authors contributed equally to this work.

    Abstract

    Although human cancers have complex genotypes and are genomically unstable, they often remain dependent on the continued presence of single-driver mutations—a phenomenon dubbed “oncogene addiction.” Such dependencies have been demonstrated in mouse models, where conditional expression systems have revealed that oncogenes able to initiate cancer are often required for tumor maintenance and progression, thus validating the pathways they control as therapeutic targets. Here, we implement an integrative approach that combines genetically defined mouse models, transcriptional profiling, and a novel inducible RNAi platform to characterize cellular programs that underlie addiction to MLL-AF9—a fusion oncoprotein involved in aggressive forms of acute myeloid leukemia (AML). We show that MLL-AF9 contributes to leukemia maintenance by enforcing a Myb-coordinated program of aberrant self-renewal involving genes linked to leukemia stem cell potential and poor prognosis in human AML. Accordingly, partial and transient Myb suppression precisely phenocopies MLL-AF9 withdrawal and eradicates aggressive AML in vivo without preventing normal myelopoiesis, indicating that strategies to inhibit Myb-dependent aberrant self-renewal programs hold promise as effective and cancer-specific therapeutics. Together, our results identify Myb as a critical mediator of oncogene addiction in AML, delineate relevant Myb target genes that are amenable to pharmacologic inhibition, and establish a general approach for dissecting oncogene addiction in vivo.

    Keywords

    Footnotes

    • Received June 21, 2011.
    • Accepted July 8, 2011.
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