TGIF1 is a negative regulator of MLL-rearranged acute myeloid leukemia

Item Type:	Article
Title:	TGIF1 is a negative regulator of MLL-rearranged acute myeloid leukemia
Creators Name:	Willer, A. and Jakobsen, J.S. and Ohlsson, E. and Rapin, N. and Waage, J. and Billing, M. and Bullinger, L. and Karlsson, S. and Porse, B.T.
Abstract:	Members of the TALE (three-amino-acid loop extension) family of atypical homeodomain-containing transcription factors are important downstream effectors of oncogenic fusion proteins involving the mixed lineage leukemia (MLL) gene. A well-characterized member of this protein family is MEIS1, which orchestrates a transcriptional program required for the maintenance of MLL-rearranged acute myeloid leukemia (AML). TGIF1/TGIF2 are relatively uncharacterized TALE transcription factors, which, in contrast to the remaining family, have been shown to act as transcriptional repressors. Given the general importance of this family in malignant hematopoiesis, we therefore tested the potential function of TGIF1 in the maintenance of MLL-rearranged AML. Gene expression analysis of MLL-rearranged patient blasts demonstrated reduced TGIF1 levels, and, in accordance, we find that forced expression of TGIF1 in MLL-AF9-transformed cells promoted differentiation and cell cycle exit in vitro, and delayed leukemic onset in vivo. Mechanistically, we show that TGIF1 interferes with a MEIS1-dependent transcriptional program by associating with MEIS1-bound regions in a competitive manner and that the MEIS1:TGIF1 ratio influence the clinical outcome. Collectively, these findings demonstrate that TALE family members can act both positively and negatively on transcriptional programs responsible for leukemic maintenance and provide novel insights into the regulatory gene expression circuitries in MLL-rearranged AML.
Keywords:	Acute Myeloid Leukemia, Bone Marrow Cells, Cell Cycle, Cell Differentiation, Chromatin Immunoprecipitation, Flow Cytometry, Gene Expression Profiling, Genetic Transcription, Histone-Lysine N-Methyltransferase, Homeobox Genes, Homeodomain Proteins, Inbred C57BL Mice, Leukemic Gene Expression Regulation, Myeloid Ecotropic Viral Integration Site 1 Protein, Myeloid-Lymphoid Leukemia Protein, Neoplasm Proteins, Repressor Proteins, Transcription Factors, Transforming Growth Factor beta1, Treatment Outcome, Animals, Mice
Source:	Leukemia
ISSN:	1476-5551
Publisher:	Nature Publishing Group
Volume:	29
Number:	5
Page Range:	1018-1031
Date:	May 2015
Official Publication:	https://doi.org/10.1038/leu.2014.307
PubMed:	View item in PubMed

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