Dominant-negative IKAROS enhances IL-3-stimulated signaling in wild-type but not BCR-ABL1+ mouse BA/F3 cells

Sofia von Palffy, Elizabeth Bulaeva, Sonja Babovic, Nagarajan Kannan, David J.H.F. Knapp, Lisa Wei, Connie J. Eaves, Philip A. Beer

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Inactivating mutations in IKZF1, the gene that encodes the transcription factor IKAROS, are recurrent in poor-prognosis human B-cell leukemias, in which these mutations co-exist with BCR-ABL1 or other genetic changes that activate similar intracellular signaling pathways. However, little is known about the mechanism(s) by which loss of IKAROS activity may co-operate with BCR-ABL1 to transform lymphoid cells. To investigate this question, we used expression of a dominant-negative isoform of IKAROS (IK6) to suppress endogenous IKAROS activity in the interleukin-3 (IL-3)-dependent mouse pro-B BA/F3 cell line and in an IL-3-independent BCR-ABL1+ derivative. We then used intracellular phospho-flow cytometry to assess the effects of BCR-ABL1 and IK6, alone and in combination, on the signaling state of the cells before and after their stimulation with IL-3. BCR-ABL1 and IK6 each produced a constitutively activated signaling phenotype and also enhanced the signaling responses of BA/F3 cells to IL-3. These effects, however, were neither equivalent nor additive, and IK6 alone was insufficient to confer the IL-3-independent growth characteristic of BCR-ABL1+ BA/F3 cells. In addition to its effects on lymphoid cells, IK6 also induced constitutively activated signaling in a subset of myeloid leukemia cell lines. Together, these studies indicate an ability of IK6 to enhance intracellular signaling in both lymphoid and myeloid cells, but not to synergize with BCR-ABL1 in this model system.

Original languageEnglish (US)
Pages (from-to)514-523.e2
JournalExperimental Hematology
Issue number7
StatePublished - Jul 1 2015

ASJC Scopus subject areas

  • Molecular Biology
  • Hematology
  • Genetics
  • Cell Biology
  • Cancer Research


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