GSK-3 Promotes Conditional Association of CREB and Its Coactivators with MEIS1 to Facilitate HOX-Mediated Transcription and Oncogenesis

Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Cancer cell (Impact Factor: 23.89). 06/2010; 17(6):597-608. DOI: 10.1016/j.ccr.2010.04.024
Source: PubMed

ABSTRACT Acute leukemias induced by MLL chimeric oncoproteins are among the subset of cancers distinguished by a paradoxical dependence on GSK-3 kinase activity for sustained proliferation. We demonstrate here that GSK-3 maintains the MLL leukemia stem cell transcriptional program by promoting the conditional association of CREB and its coactivators TORC and CBP with homedomain protein MEIS1, a critical component of the MLL-subordinate program, which in turn facilitates HOX-mediated transcription and transformation. This mechanism also applies to hematopoietic cells transformed by other HOX genes, including CDX2, which is highly expressed in a majority of acute myeloid leukemias, thus providing a molecular approach based on GSK-3 inhibitory strategies to target HOX-associated transcription in a broad spectrum of leukemias.

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    • "Tosedostat down regulated five of nine enriched genes in the V$E2F_01 promoter motif signature in HL-60 cells (acute promyelocytic leukemia) (Krige et al., 2008) where down regulation of MYC could impact a large number of TN enriched genes. The SB216763 inhibitor of GSK3Beta treatment of RS4;11 human leukemia cell line, down regulated 474 genes at least 1.5 fold that were significantly enriched for genes related to cell cycle and MYC-regulated genes (Wang et al., 2010). Knockout experiments of TLX and BMP2 indicate a down regulation of V$E2F_01, KTGGYRSGAA_UNKNOWN and V$E2F_Q3 enriched genes implicating them as possible therapeutic targets (Lee et al., 2007; Zhang et al., 2008). "
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    ABSTRACT: Triple negative (TN) breast cancers which lack expression of the estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptors convey a poor prognosis due in part to a lack of targeted therapies. To identify viable targets for the treatment of TN disease, we have conducted a gene set enrichment analysis (GSEA) on seven different breast cancer whole genome gene expression cohorts comparing TN vs. ER + HER2 - to identify consistently enriched genes that share a common promoter motif. The seven cohorts were profiled on three different genome expression platforms (Affymetrix, Illumina and RNAseq) consisting in total of 2088 samples with IHC metadata. GSEA identified enriched gene expression patterns in TN samples that share common promoter motifs associated with SOX9, E2F1, HIF1A, HMGA1, MYC BACH2, CEBPB, and GCNF/NR6A1. Unexpectedly, NR6A1 an orphan nuclear receptor normally expressed in germ cells of gonads is highly expressed in TN and ER + HER2 - samples making it an ideal drug target. With the increasing number of large sample size breast cancer cohorts, an exploratory analysis of genes that are consistently enriched in TN sharing common promoter motifs allows for the identification of possible therapeutic targets with extensive validation in patient derived data sets.
    06/2015; 4. DOI:10.1016/j.mgene.2015.04.002
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    • "In contrast, the RA, GSK-3 and/or PKA pathways might act by means of Meis proteins to create an activating complex . In particular, RA induces Meis expression (Oulad-Abdelghani et al., 1997), while both PKA and GSK-3 signaling promotes CBP-mediated transcriptional activation by means of the Meis C-terminus (Huang et al., 2005; Goh et al., 2009; Wang et al., 2010). Hence, the end result of the conversion process would be displacement of co-repressors and recruitment of coactivators . "
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    ABSTRACT: Hox genes encode transcription factors with important roles during embryogenesis and tissue differentiation. Genetic analyses initially demonstrated that interfering with Hox genes has profound effects on the specification of cell identity, suggesting that Hox proteins regulate very specific sets of target genes. However, subsequent biochemical analyses revealed that Hox proteins bind DNA with relatively low affinity and specificity. Furthermore, it became clear that a given Hox protein could activate or repress transcription depending on the context. A resolution to these paradoxes presented itself with the discovery that Hox proteins do not function in isolation, but interact with other factors in complexes. The first such "cofactors" were members of the Extradenticle/Pbx and Homothorax/Meis/Prep families. However, the list of Hox-interacting proteins has continued to grow, suggesting that Hox complexes contain many more components than initially thought. Additionally, the activities of the various components and the exact mechanisms whereby they modulate the activity of the complex remain puzzling. Here we review the various proteins known to participate in Hox complexes and discuss their likely functions. We also consider that Hox complexes of different compositions may have different activities and discuss mechanisms whereby Hox complexes may be switched between active and inactive states. Developmental Dynamics, 2013. © 2013 Wiley Periodicals, Inc.
    Developmental Dynamics 01/2014; 243(1). DOI:10.1002/dvdy.23997 · 2.67 Impact Factor
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    • "The overexpression and overactivation of GSK3b is associated to an increased cell proliferation/survival in different cancers (Luo, 2009) and to an unfavorable prognosis in AML (Kornblau et al., 2009). Given the prooncogenic role of GSK3b in stem cells as demonstrated recently in leukemia (Wang et al., 2008, 2010) and the HSC maintenance upon GSK3b inhibition (Trowbridge et al., 2006; Holmes et al., 2008), GSK3b might represent an attractive therapeutic target in leukemia. "
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    ABSTRACT: Therapeutic resistance of acute myeloid leukemia stem cells, enriched in the CD34(+)38(-)123(+) progenitor population, is supported by extrinsic factors such as the bone marrow niche. Here, we report that when adherent onto fibronectin or osteoblast components, CD34(+)38(-)123(+) progenitors survive through an integrin-dependent activation of glycogen synthase kinase 3β (GSK3β) by serine 9-dephosphorylation. Strikingly, GSK3β-mediated survival was restricted to leukemic progenitors from female patients. GSK3β inhibition restored sensitivity to etoposide, and impaired the clonogenic capacities of adherent leukemic progenitors from female patients. In leukemic progenitors from female but not male patients, the scaffolding protein RACK1, activated downstream of α(5)β(1)-integrin engagement, was specifically upregulated and controlled GSK3β activation through the phosphatase protein phosphatase 2A (PP2A). In a mirrored manner, survival of adherent progenitors (CD34(+)38(-)) from male but not female healthy donors was partially dependent on this pathway. We conclude that the GSK3β-dependent survival pathway might be sex-specific in normal immature population and flip-flopped upon leukemogenesis. Taken together, our results strengthen GSK3β as a promising target for leukemic stem cell therapy and reveal gender differences as a new parameter in anti-leukemia therapy.
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