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Di-Luoffo M, Pirenne S, Saandi T, Loriot A, Gérard C, Dauguet N, Manzano-Núñez F, Alves Souza Carvalhais N, Lamoline F, Cordi S, Konobrocka K, De Greef V, Komuta M, Halder G, Jacquemin P, Lemaigre FP. A Mouse Model of Cholangiocarcinoma Uncovers a Role for Tensin-4 in Tumor Progression. Hepatology 2021; 74:1445-1460. [PMID: 33768568 DOI: 10.1002/hep.31834] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 03/05/2021] [Accepted: 03/14/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIMS Earlier diagnosis and treatment of intrahepatic cholangiocarcinoma (iCCA) are necessary to improve therapy, yet limited information is available about initiation and evolution of iCCA precursor lesions. Therefore, there is a need to identify mechanisms driving formation of precancerous lesions and their progression toward invasive tumors using experimental models that faithfully recapitulate human tumorigenesis. APPROACH AND RESULTS To this end, we generated a mouse model which combines cholangiocyte-specific expression of KrasG12D with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet-induced inflammation to mimic iCCA development in patients with cholangitis. Histological and transcriptomic analyses of the mouse precursor lesions and iCCA were performed and compared with human analyses. The function of genes overexpressed during tumorigenesis was investigated in human cell lines. We found that mice expressing KrasG12D in cholangiocytes and fed a DDC diet developed cholangitis, ductular proliferations, intraductal papillary neoplasms of bile ducts (IPNBs), and, eventually, iCCAs. The histology of mouse and human IPNBs was similar, and mouse iCCAs displayed histological characteristics of human mucin-producing, large-duct-type iCCA. Signaling pathways activated in human iCCA were also activated in mice. The identification of transition zones between IPNB and iCCA on tissue sections, combined with RNA-sequencing analyses of the lesions supported that iCCAs derive from IPNBs. We further provide evidence that tensin-4 (TNS4), which is stimulated by KRASG12D and SRY-related HMG box transcription factor 17, promotes tumor progression. CONCLUSIONS We developed a mouse model that faithfully recapitulates human iCCA tumorigenesis and identified a gene cascade which involves TNS4 and promotes tumor progression.
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Affiliation(s)
- Mickaël Di-Luoffo
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Sophie Pirenne
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium.,Department of Pathology, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Thoueiba Saandi
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Axelle Loriot
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Claude Gérard
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Nicolas Dauguet
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium.,CYTF Platform, Université catholique de Louvain, Brussels, Belgium
| | | | | | - Florence Lamoline
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Sabine Cordi
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | | | - Vitaline De Greef
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Mina Komuta
- Department of Pathology, Keio University School of Medicine, Tokyo, Japan
| | - Georg Halder
- VIB Center for Cancer Biology and KU Leuven Department of Oncology, University of Leuven, Leuven, Belgium
| | - Patrick Jacquemin
- de Duve Institute, Université catholique de Louvain, Brussels, Belgium
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2
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Chamouine A, Saandi T, Muszlak M, Larmaraud J, Lambrecht L, Poisson J, Balicchi J, Pissard S, Elenga N. High fetal hemoglobin level is associated with increased risk of cerebral vasculopathy in children with sickle cell disease in Mayotte. BMC Pediatr 2020; 20:302. [PMID: 32563256 PMCID: PMC7305627 DOI: 10.1186/s12887-020-02187-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/01/2020] [Indexed: 11/10/2022] Open
Abstract
Background Understanding the genetics underlying the heritable subphenotypes of sickle cell anemia, specific to each population, would be prognostically useful and could inform personalized therapeutics.The objective of this study was to describe the genetic modulators of sickle cell disease in a cohort of pediatric patients followed up in Mayotte. Methods This retrospective cohort study analyzed clinical and biological data, collected between January1st2007 and December 31st2017, in children younger than 18 years. Results We included 185 children with 72% SS, 16% Sβ0-thalassemia and 12% Sβ + thalassemia. The average age was 9.5 years; 10% of patients were lost to follow up. The Bantu haplotype was associated with an increase in hospitalizations and transfusions. The alpha-thalassemic mutation was associated with a decrease of hemolysis biological parameters (anemia, reticulocytes), and a decrease of cerebral vasculopathy. The Single Nucleotide Polymorphisms BCL11A rs4671393, BCL11A rs11886868, BCL11A rs1427407 and HMIP rs9399137 were associated with the group of children with HbF > 10%. Patients with HbF > 10% presented a significant risk of early onset of cerebral vasculopathy. Conclusions The most remarkable result of our study was the association of SNPs with clinically relevant phenotypic groups. BCL11A rs4671393, BCL11A rs11886868, BCL11A rs1427407 and HMIP rs9399137 were correlated with HbF > 10%, a group that has a higher risk of cerebral vasculopathy and should be oriented towards the hemolytic sub-phenotype.
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Affiliation(s)
- Abdourahim Chamouine
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France.
| | - Thoueiba Saandi
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France
| | - Mathias Muszlak
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France
| | - Juliette Larmaraud
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France
| | - Laurent Lambrecht
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France
| | - Jean Poisson
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France
| | - Julien Balicchi
- Pediatric Unit, Mamoudzou General Hospital, 1, Rue de l'Hopital, BP 4, 97600, Mamoudzou, Mayotte, France
| | - Serge Pissard
- APHP, GHU H Mondor, departement de genetique, INSERM-IMRB U955eq2/GREx, 51 Avenue du Maréchal de Lattre de Tassigny, 94010, Créteil Cedex, France
| | - Narcisse Elenga
- Pediatric Medicine and Surgery, Cayenne General Hospital, Cayenne, French Guiana, France
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Balbinot C, Vanier M, Armant O, Nair A, Penichon J, Soret C, Martin E, Saandi T, Reimund JM, Deschamps J, Beck F, Domon-Dell C, Gross I, Duluc I, Freund JN. Fine-tuning and autoregulation of the intestinal determinant and tumor suppressor homeobox gene CDX2 by alternative splicing. Cell Death Differ 2017; 24:2173-2186. [PMID: 28862703 DOI: 10.1038/cdd.2017.140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/23/2017] [Accepted: 07/25/2017] [Indexed: 12/20/2022] Open
Abstract
On the basis of phylogenetic analyses, we uncovered a variant of the CDX2 homeobox gene, a major regulator of the development and homeostasis of the gut epithelium, also involved in cancer. This variant, miniCDX2, is generated by alternative splicing coupled to alternative translation initiation, and contains the DNA-binding homeodomain but is devoid of transactivation domain. It is predominantly expressed in crypt cells, whereas the CDX2 protein is present in crypt cells but also in differentiated villous cells. Functional studies revealed a dominant-negative effect exerted by miniCDX2 on the transcriptional activity of CDX2, and conversely similar effects regarding several transcription-independent functions of CDX2. In addition, a regulatory role played by the CDX2 and miniCDX2 homeoproteins on their pre-mRNA splicing is displayed, through interactions with splicing factors. Overexpression of miniCDX2 in the duodenal Brunner glands leads to the expansion of the territory of these glands and ultimately to brunneroma. As a whole, this study characterized a new and original variant of the CDX2 homeobox gene. The production of this variant represents not only a novel level of regulation of this gene, but also a novel way to fine-tune its biological activity through the versatile functions exerted by the truncated variant compared to the full-length homeoprotein. This study highlights the relevance of generating protein diversity through alternative splicing in the gut and its diseases.
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Affiliation(s)
- Camille Balbinot
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Marie Vanier
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Olivier Armant
- Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Postfach 3640, Karlsruhe 76021, Germany
| | - Asmaa Nair
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Julien Penichon
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Christine Soret
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Elisabeth Martin
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Thoueiba Saandi
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Jean-Marie Reimund
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Jacqueline Deschamps
- Hubrecht Institute, Developmental Biology and Stem Cell Research, Uppsalalaan 8, Utrecht 3584 CT, The Netherlands
| | - Felix Beck
- Barts and The London School of Medicine and Dentistry, London E1 2ES, UK
| | - Claire Domon-Dell
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Isabelle Gross
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Isabelle Duluc
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
| | - Jean-Noël Freund
- Université de Strasbourg, Inserm, UMR_S1113, FMTS, Strasbourg 67000, France
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Cordi S, Godard C, Saandi T, Jacquemin P, Monga SP, Colnot S, Lemaigre FP. Role of β-catenin in development of bile ducts. Differentiation 2016; 91:42-9. [PMID: 26856660 DOI: 10.1016/j.diff.2016.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 01/15/2016] [Accepted: 02/01/2016] [Indexed: 01/13/2023]
Abstract
Beta-catenin is known to play stage- and cell-specific functions during liver development. However, its role in development of bile ducts has not yet been addressed. Here we used stage-specific in vivo gain- and loss-of-function approaches, as well as lineage tracing experiments in the mouse, to first demonstrate that β-catenin is dispensable for differentiation of liver precursor cells (hepatoblasts) to cholangiocyte precursors. Second, when β-catenin was depleted in the latter, maturation of cholangiocytes, bile duct morphogenesis and differentiation of periportal hepatocytes from cholangiocyte precursors was normal. In contrast, stabilization of β-catenin in cholangiocyte precursors perturbed duct development and cholangiocyte differentiation. We conclude that β-catenin is dispensable for biliary development but that its activity must be kept within tight limits. Our work is expected to significantly impact on in vitro differentiation of stem cells to cholangiocytes for toxicology studies and disease modeling.
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Affiliation(s)
- Sabine Cordi
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75/B1-7503, 1200 Brussels, Belgium
| | - Cécile Godard
- Institut Cochin, INSERM U1016; CNRS, UMR8104; Equipe labellisée Ligue Nationale Contre le Cancer; Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Thoueiba Saandi
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75/B1-7503, 1200 Brussels, Belgium
| | - Patrick Jacquemin
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75/B1-7503, 1200 Brussels, Belgium
| | - Satdarshan P Monga
- Department of Pathology, Department of Medicine, University of Pittsburgh School of Medicine, 200 Lothrop St, Rm S-422 BST, Pittsburgh, PA 15261, USA
| | - Sabine Colnot
- Institut Cochin, INSERM U1016; CNRS, UMR8104; Equipe labellisée Ligue Nationale Contre le Cancer; Université Paris Descartes, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Frédéric P Lemaigre
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75/B1-7503, 1200 Brussels, Belgium.
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Derbal-Wolfrom L, Pencreach E, Saandi T, Aprahamian M, Martin E, Greferath R, Tufa E, Choquet P, Lehn JM, Nicolau C, Duluc I, Freund JN. Increasing the oxygen load by treatment with myo-inositol trispyrophosphate reduces growth of colon cancer and modulates the intestine homeobox gene Cdx2. Oncogene 2012; 32:4313-8. [PMID: 23045284 DOI: 10.1038/onc.2012.445] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 08/03/2012] [Accepted: 08/09/2012] [Indexed: 12/11/2022]
Abstract
Preventing tumor neovascularisation is one of the strategies recently developed to limit the dissemination of cancer cells and apparition of metastases. Although these approaches could improve the existing treatments, a number of unexpected negative effects have been reported, mainly linked to the hypoxic condition and the subsequent induction of the pro-oncogenic hypoxia inducible factor(s) resulting from cancer cells' oxygen starvation. Here, we checked in vivo on colon cancer cells an alternative approach. It is based on treatment with myo-inositol trispyrophosphate (ITPP), a molecule that leads to increased oxygenation of tumors. We provide evidence that ITPP increases the survival of mice in a model of carcinomatosis of human colon cancer cells implanted into the peritoneal cavity. ITPP also reduced the growth of subcutaneous colon cancer cells xenografted in nu/nu mice. In the subcutaneous tumors, ITPP stimulated the expression of the homeobox gene Cdx2 that is crucial for intestinal differentiation and that also has an anti-tumoral function. On this basis, human colon cancer cells were cultured in vitro in hypoxic conditions. Hypoxia was shown to decrease the level of Cdx2 protein, mRNA and the activity of the Cdx2 promoter. This decline was unrelated to the activation of HIF1α and HIF2α by hypoxia. However, it resulted from the activation of a phosphatidylinositol 3-kinases-like mitogen-activated protein kinase pathway, as assessed by the fact that LY294002 and U0126 restored high Cdx2 expression in hypoxia. Corroborating these results, U0126 recapitulated the increase of Cdx2 triggered by ITPP in subcutaneous colon tumor xenografts. The present study provides evidence that a chemical compound that increases oxygen pressure can antagonize the hypoxic setting and reduce the growth of human colon tumors implanted in nu/nu mice.
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Saandi T, Baraille F, Derbal-Wolfrom L, Cattin AL, Benahmed F, Martin E, Cardot P, Duclos B, Ribeiro A, Freund JN, Duluc I. Regulation of the tumor suppressor homeogene Cdx2 by HNF4α in intestinal cancer. Oncogene 2012; 32:3782-8. [PMID: 22986531 DOI: 10.1038/onc.2012.401] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 07/16/2012] [Accepted: 07/17/2012] [Indexed: 12/21/2022]
Abstract
The gut-specific homeotic transcription factor Cdx2 is a crucial regulator of intestinal development and homeostasis, which is downregulated in colorectal cancers (CRC) and exhibits a tumor suppressor function in the colon. We have previously established that several endodermal transcription factors, including HNF4α and GATA6, are involved in Cdx2 regulation in the normal gut. Here we have studied the role of HNF4α in the mechanism of deregulation of Cdx2 in colon cancers. Crossing Apc(Δ14/+) mice prone to spontaneous intestinal tumor development with pCdx2-9LacZ transgenic mice containing the LacZ reporter under the control of the 9.3-kb Cdx2 promoter showed that this promoter segment contains sequences recapitulating the decrease of Cdx2 expression in intestinal cancers. Immunohistochemistry revealed that HNF4α, unlike GATA6, exhibited a similar decrease to Cdx2 in genetic (Apc(min/+) and Apc(Δ14/+)) and chemically induced (Azoxymethane (AOM) treatment) models of intestinal tumors in mice. HNF4α and Cdx2 also exhibited a comparable deregulated pattern in human CRC. Correlated patterns were observed between HNF4α and Cdx2 in several experimental models of human colon cancer cell lines: xenografts in nude mice, wound healing and glucose starvation. Furthermore, Cdx2 decreased by knocking down HNF4α in human colon cancer cells using siRNA and in the colon of mice conditionally knocked out for the Hnf4α gene in the adult intestine (Hnf4α(f/f);VilCre(ERT2) mice). Finally, the conditionally knocked out mice Hnf4α(f/f);VilCre(ERT2) treated with the carcinogen AOM developed colorectal tumors earlier than wild-type mice, as previously reported for mice with a reduced Cdx2 expression. In conclusion, this study provides evidence that the downregulation of HNF4α is an important determinant of the reduced expression of the Cdx2 tumor suppressor gene in intestinal cancers. Consistently, similar to Cdx2, HNF4α exerts a tumor suppressor function in the colon in that its loss of function facilitates tumor progression.
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Affiliation(s)
- T Saandi
- Inserm, Unité 682, Strasbourg, France
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Saandi T, Cattin A, Derbal L, Benahmed F, Martin E, Ribeiro A, Freund J, Duluc I. 144 The HNF4alpha-Cdx2 Axis in the Intestinal Cancer. Eur J Cancer 2012. [DOI: 10.1016/s0959-8049(12)70844-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Stringer EJ, Duluc I, Saandi T, Davidson I, Bialecka M, Sato T, Barker N, Clevers H, Pritchard CA, Winton DJ, Wright NA, Freund JN, Deschamps J, Beck F. Cdx2 determines the fate of postnatal intestinal endoderm. Development 2012; 139:465-74. [PMID: 22190642 PMCID: PMC3252350 DOI: 10.1242/dev.070722] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2011] [Indexed: 12/19/2022]
Abstract
Knock out of intestinal Cdx2 produces different effects depending upon the developmental stage at which this occurs. Early in development it produces histologically ordered stomach mucosa in the midgut. Conditional inactivation of Cdx2 in adult intestinal epithelium, as well as specifically in the Lgr5-positive stem cells, of adult mice allows long-term survival of the animals but fails to produce this phenotype. Instead, the endodermal cells exhibit cell-autonomous expression of gastric genes in an intestinal setting that is not accompanied by mesodermal expression of Barx1, which is necessary for gastric morphogenesis. Cdx2-negative endodermal cells also fail to express Sox2, a marker of gastric morphogenesis. Maturation of the stem cell niche thus appears to be associated with loss of ability to express positional information cues that are required for normal stomach development. Cdx2-negative intestinal crypts produce subsurface cystic vesicles, whereas untargeted crypts hypertrophy to later replace the surface epithelium. These observations are supported by studies involving inactivation of Cdx2 in intestinal crypts cultured in vitro. This abolishes their ability to form long-term growing intestinal organoids that differentiate into intestinal phenotypes. We conclude that expression of Cdx2 is essential for differentiation of gut stem cells into any of the intestinal cell types, but they maintain a degree of cell-autonomous plasticity that allows them to switch on a variety of gastric genes.
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Affiliation(s)
- Emma J. Stringer
- Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
| | - Isabelle Duluc
- INSERM, U682, Université de Strasbourg, Strasbourg, France
| | | | - Irwin Davidson
- CNRS, UMR7104, Strasbourg, France; Université de Strasbourg, Strasbourg, France
| | - Monika Bialecka
- Hubrecht Institute, Developmental Biology and Stem Cell Research, and Utrecht University Medical Center, Utrecht, The Netherlands
| | - Toshiro Sato
- Hubrecht Institute, Developmental Biology and Stem Cell Research, and Utrecht University Medical Center, Utrecht, The Netherlands
| | - Nick Barker
- Institute of Medical Biology, 8A Biomedical Grove, 06-06 Immunos, Singapore 138648
| | - Hans Clevers
- Hubrecht Institute, Developmental Biology and Stem Cell Research, and Utrecht University Medical Center, Utrecht, The Netherlands
| | - Catrin A. Pritchard
- Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
| | - Doug J. Winton
- Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Cambridge CB2 0RE, UK
| | - Nicholas A. Wright
- St Bartholomew’s and The Royal London School of Medicine and Dentistry, Turner Street, Whitechapel, London E1 2DD, UK
| | | | - Jacqueline Deschamps
- Hubrecht Institute, Developmental Biology and Stem Cell Research, and Utrecht University Medical Center, Utrecht, The Netherlands
| | - Felix Beck
- Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
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Renouf B, Soret C, Saandi T, Delalande F, Martin E, Vanier M, Duluc I, Gross I, Freund JN, Domon-Dell C. Cdx2 homeoprotein inhibits non-homologous end joining in colon cancer but not in leukemia cells. Nucleic Acids Res 2011; 40:3456-69. [PMID: 22189105 PMCID: PMC3333856 DOI: 10.1093/nar/gkr1242] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cdx2, a gene of the paraHox cluster, encodes a homeodomain transcription factor that plays numerous roles in embryonic development and in homeostasis of the adult intestine. Whereas Cdx2 exerts a tumor suppressor function in the gut, its abnormal ectopic expression in acute leukemia is associated to a pro-oncogenic function. To try to understand this duality, we have hypothesized that Cdx2 may interact with different protein partners in the two tissues and set up experiments to identify them by tandem affinity purification. We show here that Cdx2 interacts with the Ku heterodimer specifically in intestinal cells, but not in leukemia cells, via its homeodomain. Ku proteins do not affect Cdx2 transcriptional activity. However, Cdx2 inhibits in vivo and in vitro the DNA repair activity mediated by Ku proteins in intestinal cells. Whereas Cdx2 does not affect the recruitment of Ku proteins and DNA-PKcs into the DNA repair complex, it inhibits DNA-PKcs activity. Thus, we report here a new function of Cdx2, acting as an inhibitor of the DNA repair machinery, that may contribute to its tumor suppressor function specifically in the gut.
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Bouakaze C, Eschbach J, Fouquerel E, Gasser I, Kieffer E, Krieger S, Milosevic S, Saandi T, Florentz C, Maréchal-Drouard L, Labouesse M. "OpenLAB": A 2-hour PCR-based practical for high school students. Biochem Mol Biol Educ 2010; 38:296-302. [PMID: 21567848 DOI: 10.1002/bmb.20408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Strasbourg University PhD school in Life and Health Sciences launched an initiative called "OpenLAB." This project was developed in an effort to help high school teenagers understand theoretical and abstract concepts in genetics. A second objective of this program is to help students in defining their future orientation and to attract them to biology. The general idea is a 2-hour PCR-based practical that is developed around a fictitious criminal investigation. The practical is taught by PhD graduate students who bring all the required reagents and modern equipment into the classroom. Running the PCR provides free time dedicated to discussions with students about their future plans after the high school diploma. A specific website and a powerpoint presentation were developed to provide appropriate scientific information. Starting on a modest scale in Strasbourg in December 2008, "OpenLAB" was rapidly and well received all around, visiting 53 classes spread over a 200 km area in Alsace until May 2009. It permitted interactions with almost one thousand students in their last year of high school, with the prospect to visit 20% more classes this school year. Our experience, along with feedback from students and their teachers, suggests that it is possible to reach out to many students and have a strong impact with a rather limited budget.
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Affiliation(s)
- Caroline Bouakaze
- Ecole Doctorale des Sciences de la Vie et de la Santé (ED414), Université de Strasbourg, 12 rue de l'Université, F-67000 Strasbourg; Faculté de Médecine, 11 rue Humann, F-67000 STRASBOURG
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