Phosphorylation of the homeotic tumor suppressor Cdx2 mediates its ubiquitin-dependent proteasome degradation

Groß, Isabelle; Lhermitte, Benoît; Domon‐Dell, Claire; Duluc, Isabelle; Martin, Elisabeth; Gaiddon, Christian; Kédinger, Michèle; Freund, Jean–Noël

doi:10.1038/sj.onc.1208945

Cited by 41 publications

(44 citation statements)

References 41 publications

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“…Protein levels for Cdx1 decline earlier than for Cdx2 and Cdx4. All three proteins form doublets on SDS gels, suggestive of post-translational modification (Gross et al, 2005). Fig.…”

Section: Oe1 Oe2 and Oe4 Transgenes Upregulate CDX Expression Withinmentioning

confidence: 99%

Increased Cdx protein dose effects upon axial patterning in transgenic lines of mice

2008

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To investigate the link between Cdx protein concentration and axial patterning in embryos, we made lines of mice OE1, OE2 and OE4 that overexpress each of the Cdx genes Cdx1, Cdx2 and Cdx4, respectively. The lines carry Cdx transgenes under the transcriptional control of their own promoter/enhancer elements. Transgenic embryos show Cdx transcription at 8.5 to 8.7 days within normal spatial domains for Cdx expression (primitive streak/tailbud), yet, overall, they contain elevated levels of Cdx proteins. Increased doses of Cdx proteins result in homeotic shifts in vertebral types along most of the vertebral column, with transformations being most obvious within the cervical region. Most of the shifts are anterior-to-posterior transformations and the anterior limits of these are commonly skull/vertebra 1 (v1) for OE1, v1/v2 for OE2 and v7 for OE4. OE embryos display anterior shifts in the expression of a Hoxa7/lacZ reporter within neural, paraxial and lateral plate mesoderm tissues. Hoxa7/lacZ expression commences at the normal time in OE1 and OE4 embryos. OE2 embryos display a forward shift in the gradient of Cdx2 protein along the axis, suggesting that a Cdx morphogen gradient model could account, at least in part, for the homeotic shifts in vertebral types. OE mice display additional defects: forelimb deficiencies in OE1, multiple tail axes, vertebral mis-alignments and axial truncations in OE2.

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“…Protein levels for Cdx1 decline earlier than for Cdx2 and Cdx4. All three proteins form doublets on SDS gels, suggestive of post-translational modification (Gross et al, 2005). Fig.…”

Section: Oe1 Oe2 and Oe4 Transgenes Upregulate CDX Expression Withinmentioning

confidence: 99%

Increased Cdx protein dose effects upon axial patterning in transgenic lines of mice

2008

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“…The plasmids pFlag-CBF1 encoding CBF1/CSL, 21 pMyc-NICD1 encoding the intracellular domain of Notch1, 22 and the reporter vector 4xwtCBF1Luc 21 have been described. Transfected cells were visualized by indirect immunofluorescence as previously described, 23 using mouse anti-Flag antibody (dilution 1:1000; Sigma) and Cy3-labeled antimouse antibody (dilution 1:3000; Interchim, Montluçon, France). CDX2 was detected using anti-CDX2 antibody (dilution 1:500; Biogenex) and Alexa-488-conjugated anti-mouse antibody (dilution 1:3000; Molecular Probes Invitrogen).…”

Section: Immunohistochemistry and Western Blotsmentioning

confidence: 99%

The Microenvironment Controls CDX2 Homeobox Gene Expression in Colorectal Cancer Cells

Benahmed¹,

Groß²,

Guenot³

et al. 2007

The American Journal of Pathology

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The homeobox gene CDX2 plays a major role in development, especially in the gut, and it also acts as a tumor suppressor in the adult colon. Using orthotopic and heterotopic xenografts of human primary colorectal tumor cells and cell lines in nude mice, we addressed the effect of the microenvironment on CDX2 expression. In cells expressing CDX2 at a high level in culture, this level was maintained in subcutaneous grafts but was reduced when implanted into the cecum wall. Reciprocally, in cells with low CDX2 expression in culture, the level remained low in grafts into the cecum wall but was stimulated subcutaneously. In vitro co-cultures showed that CDX2 expression was activated in cells grown on layers of skin fibroblasts but not on intestinal fibroblasts. The stimulation was transcriptional, as assessed by transfection experiments with reporter plasmids containing the murine Cdx2 promoter. Together, these data demonstrate experimentally that CDX2 expression is adaptable and strongly dependent on the microenvironment surrounding the tumor cells. We exclude a role of the Notch pathway in this regulation. The regulation of CDX2 by the microenvironment might be relevant during the process of metastatic dissemination when the gene is transiently turned down in invasive cells. Colorectal cancer (CRC) is a major problem of public health because of its severity and high incidence. The severity is mainly attributable to the propensity of tumor cells to invade the stroma and eventually to disseminate into metastases. It is generally thought that the progression along the adenoma, carcinoma, metastasis sequence is accompanied by the accumulation of an increasing number of irreversible genomic alterations.1 In addition, reversible changes induced by the microenvironment facing malignant cells are also considered to be of prime importance for tumor cell invasion and metastatic dissemination.2 For instance, the epithelial-mesenchymal transition is a hallmark of invasive cells that escape the primary tumor, whereas the circulating tumor cells can undergo mesenchymal-epithelial transition at the homing site to form metastases.The major reversible changes reported in invasive cells spreading out from primary tumors include the decrease of membranous E-cadherin, the massive nuclear translocation of ␤-catenin, the activation of the cell cycle inhibitor p16, and the intracellular accumulation of the basement membrane molecule laminin-␥2. 2 Recently, a careful analysis of primary CRCs and liver metastases led us to show that invasive CRC cells are also characterized by a reversible decline of the intestine-specific homeoprotein CDX2.3 CDX2 is a transcription factor that plays a central role in embryos to define the organ-specific identity of the presumptive gut endoderm. 4 -7 At the adult stage, it belongs to the network that controls proliferation and differentiation of the continuously renewing gut epithelium.8,9 CDX2 also has a tumor suppressor function in the colon, because Cdx2 ϩ/Ϫ mice are hypersensitive to CRC progression in...

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“…Such a pattern of Cdx2 protein expression in the intestine has also been reported previously (31). In fact, in proliferative undifferentiated cells, Cdx2 is phosphorylated by active Cdk2-associated complexes, targeting Cdx2 for rapid degradation by the ubiquitin/proteasome pathway (11,26,27).…”

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confidence: 99%

Constitutive activation of the MEK/ERK pathway inhibits intestinal epithelial cell differentiation

Lemieux

Boucher

Mongrain

et al. 2011

American Journal of Physiology-Gastrointestinal and Liver Physi

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The Ras/Raf/MEK/ERK cascade regulates intestinal epithelial cell proliferation. Indeed, while barely detectable in differentiated cells of the villi, ERK1/2-activated forms are detected in the nucleus of undifferentiated human intestinal crypt cells. In addition, we and others have reported that ERKs are selectively inactivated during enterocyte differentiation. However, whether inactivation of the ERK pathway is necessary for inhibition of both proliferation and induction of differentiation of intestinal epithelial cells is unknown. Human Caco-2/15 cells, undifferentiated crypt IEC-6 cells, and differentiating Cdx3-expressing IEC-6 cells were infected with retroviruses encoding either a hemagglutinin (HA)-tagged MEK1 wild type (wtMEK) or a constitutively active S218D/S222D MEK1 mutant (caMEK). Protein and gene expression was assessed by Western blotting, semiquantitative RT-PCR, and real-time PCR. Morphology was analyzed by transmission electron microscopy. We found that 1) IEC-6/Cdx3 cells formed multicellular layers after confluence and differentiated after 30 days in culture, as assessed by increased polarization, microvilli formation, expression of differentiation markers, and ERK1/2 inhibition; 2) while activated MEK prevented neither the inhibition of ERK1/2 activities nor the differentiation process in postconfluent Caco-2/15 cells, caMEK expression prevented ERK inhibition in postconfluent IEC-6/Cdx3 cells, thus leading to maintenance of elevated ERK1/2 activities; 3) caMEK-expressing IEC-6/Cdx3 cells exhibited altered multicellular structure organization, poorly defined tight junctions, reduced number of microvilli on the apical surface, and decreased expression of the hepatocyte nuclear factor 1α transcription factor and differentiation markers, namely apolipoprotein A-4, fatty acid-binding protein, calbindin-3, mucin 2, alkaline phosphatase, and sucrase-isomaltase; and 4) increased Cdx3 phosphorylation on serine-60 (S60) in IEC-6/Cdx3 cells expressing caMEK led to decreased Cdx2 transactivation potential. These results indicate that inactivation of the ERK pathway is required to ensure the full Cdx2/3 transcriptional activity necessary for intestinal epithelial cell terminal differentiation.

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Phosphorylation of the homeotic tumor suppressor Cdx2 mediates its ubiquitin-dependent proteasome degradation

Cited by 41 publications

References 41 publications

Increased Cdx protein dose effects upon axial patterning in transgenic lines of mice

Increased Cdx protein dose effects upon axial patterning in transgenic lines of mice

The Microenvironment Controls CDX2 Homeobox Gene Expression in Colorectal Cancer Cells

Constitutive activation of the MEK/ERK pathway inhibits intestinal epithelial cell differentiation

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