Site-Specific Epithelial-Mesenchymal Interactions in Digestive Neuroendocrine Tumors

Dumortier, Jérôme; Ratineau, Christelle; Scoazec, Jean‐Yves; Pourreyron, Céline; Anderson, Wena; Jacquier, Marie-France; Blanc, M.; Bernard, Christine; Bellaton, Claire; Rémy, Lionel; Chayvialle, Jean‐Alain; Roche, Colette

doi:10.1016/s0002-9440(10)64771-2

Cited by 17 publications

(18 citation statements)

References 36 publications

(34 reference statements)

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“…Tumors showed no evidence of endocrine differentiation, whatever the animal setup. Importantly, the characteristic expression of chromogranin A was lacking in experiments using reagents that were previously validated on experimental endocrine tumors in rodents (13).…”

Section: Discussionmentioning

confidence: 99%

“…DNA synthesis was determined through [ 3 H]thymidine incorporation (1 mCi/ml) during a 4-h period as described previously (13).…”

Section: Methodsmentioning

confidence: 99%

“…After electrophoresis, proteins were transferred onto nitrocellulose membranes (polyvinylidene difluoride membranes for menin expression). Western blotting was performed as described previously (13). The polyclonal antibodies used were menin (1:1500), cyclin D1 (1:200), cyclin D3 (1: 1000), Cdk4 (1:200), T␤RII (1:500) (Santa Cruz Biotechnology), and cyclophilin A (Upstate Biotechnology, 1:3000).…”

Section: Methodsmentioning

confidence: 99%

“…Rats were subsequently immunodepressed as described previously (13). Animals were sacrificed 3 weeks after cell inoculation and tumors were removed, fixed in 10% formalin, and then embedded in paraffin for histological analysis or frozen directly in liquid nitrogen for RNA analysis.…”

Section: Methodsmentioning

confidence: 99%

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Reduction of Menin Expression Enhances Cell Proliferation and Is Tumorigenic in Intestinal Epithelial Cells

Ratineau

Bernard

Poncet

et al. 2004

Journal of Biological Chemistry

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Menin, the product of the tumor suppressor gene MEN1, is widely expressed in mammalian endocrine and non-endocrine tissues, including intestine. Its known abundant expression in several types of cells with high proliferative capacity led us to investigate the physiological function of the protein menin in intestinal epithelium, one of the most rapidly growing epithelia. Here we showed that the Men1 gene is mainly expressed in the crypt compartment of the proximal small intestine and that its expression was increased during fasting in vivo, both suggesting a role of menin in the control of cell growth. Indeed, specific reduction of menin expression by transfected antisense cDNA in the rat duodenal crypt-like cell line, IEC-17, increased cell proliferation. Menin is a 610 amino acid protein encoded by the tumor suppressor gene MEN1 (1). Germline mutations are responsible for multiple endocrine neoplasia type 1 (MEN1), 1 an autosomal-dominant cancer syndrome featuring parathyroid cell hyperplasia and tumors of the pituitary and duodeno-pancreatic endocrine tissues. Biallelic inactivation of the Men1 gene in mice results in embryonic lethality at mid-gestation (2, 3). Heterozygote Men1 mutant mice develop the similar range of endocrine tumors as seen in the human MEN1 syndrome (4).Menin is highly conserved in humans and rodents (5, 6). The protein sequence does not include consensus motives from which its putative function could be deduced. Menin has been shown to interact directly with an ever increasing list of molecular partners such as JunD, Smad3, nm23, NF-B (for a review, see Ref. 7). It is predominantly located in the nucleus, with two independent nuclear localization signals (1).Despite the endocrine specificity of the MEN1 syndrome tumors, menin RNA and protein are widely expressed in endocrine and non-endocrine rodent and human tissues (6, 8 -10), suggesting a large panel of physiological functions for the protein. In the intestinal tract of mouse and rat, menin RNA was detected by Northern blotting in small and large intestine (6,8). Interestingly, in adult human tissues, the expression of the MEN1 gene detected by in situ hybridization was predominant in actively proliferating cells such as the proliferative phase of endometrium and parabasal cells of the esophageal mucosa, but faint in the secretory phase of the endometrium (10).The aim of the present study was to investigate the physiological function of menin in the intestinal epithelium, which is among the most rapidly renewing tissues of the mammalian organism. First, we provide direct evidence that the Men1 gene is mainly expressed in the crypt compartment of the small intestine. We then demonstrate that menin inactivation increases cell proliferation and promotes tumorigenesis both in vitro and in vivo in intestinal epithelial cells. EXPERIMENTAL PROCEDURESIn Situ Hybridization-Deparaffinized mouse proximal small intestine sections were treated for 10 min with pepsin (0.4%) in 0.2 N HCl, followed by ethanol treatment and air drying. Hybridization ...

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Section: Discussionmentioning

confidence: 99%

“…DNA synthesis was determined through [ 3 H]thymidine incorporation (1 mCi/ml) during a 4-h period as described previously (13).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Reduction of Menin Expression Enhances Cell Proliferation and Is Tumorigenic in Intestinal Epithelial Cells

Ratineau

Bernard

Poncet

et al. 2004

Journal of Biological Chemistry

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“…35,36 PDX0 and PDX39P cells were inoculated into two groups of immunosuppressed newborn rats, and tumors and lungs were excised for further analyses after 21 days. Although similar in appearance ( Figure 5A), PDX39P-induced tumors were 30% smaller compared to PDX0-induced tumors ( Figure 5B).…”

Section: Proprotein Convertases Inhibition Increases Metastases Formamentioning

confidence: 99%

Inhibition of Proprotein Convertases Enhances Cell Migration and Metastases Development of Human Colon Carcinoma Cells in a Rat Model

Nejjari

Berthet

Rigot

et al. 2004

The American Journal of Pathology

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Although proprotein convertases are involved in tumor development, nothing is known about their role in metastatic dissemination. To investigate the involvement of convertase inhibition, we used human colon carcinoma cells overexpressing ␣1-antitrypsin Portland (␣1-PDX, PDX39P cells), a potent convertase inhibitor. We previously reported that these cells bear uncleaved integrin ␣ subunits and display an altered attachment to vitronectin that is correlated with defects in the intracellular signaling pathways activated by ␣v␤5 integrin ligation. In this study, we demonstrate that the inhibition of proprotein convertase activity either by overexpression of ␣1-PDX or with the synthetic inhibitor decanoyl-Arg-Val-Lys-Arg-chloromethylketone (dec-RVKR-cmk) led to a significant increase in cell migration supported by the ␣v␤5 integrin. A collagen gel invasion assay showed that PDX39P cells also displayed an invasive ability, contrary to control cells. Moreover, when injected to immunosuppressed newborn rats, PDX39P cells were highly invasive, as they induce 10 times more metastases than mock-transfected cells. In addition, the aggressiveness of PDX39P cells can be greatly reduced by a function-blocking monoclonal antibody (mAb) against the ␣v subunit. It thus seems that inhibition of proprotein convertases enhances the in vivo invasiveness of colon tumor cells likely due to an increase in cell migration mediated by ␣v integrins. The acquisition of cell motility and the capacity to invade basement matrix membranes and adjacent tissues play a central role in the complex multi-step process of metastasis. Cell migration is the result of dynamic interactions between the cell, the extracellular matrix (ECM), and the cytoskeleton. Integrins connect the ECM proteins outside to the actin cytoskeleton within the cell, allowing the traction required for cell migration. 1,2 Integrins also play a crucial role in signal transduction events that control anchorage-independent growth and survival of tumor cells (for reviews, see references [3][4][5] ). Therefore, these adhesion molecules play a pivotal role in tumor cell invasion and metastasis. [5][6][7] Integrins are heterodimeric proteins composed by the non-covalent association of ␣ and ␤ subunits. Some integrin ␣ chains undergo a post-translational cleavage in their extracellular domain by furin and PC5A, two proprotein convertases (PCs) of the subtilisin/kexin family. 8,9 The role of this cleavage in integrin function remains unclear. Arguably, this post-translational processing of the ␣ chain is not required for ligand binding, 10 -12 but is essential for the signaling function of ␣6␤1 and ␣v␤5 integrins. 10,13 Moreover, recent data suggest that the ␣6 subunit cleavage might be linked to the differentiation state of lens cells. 14 PCs are responsible for the biological activation of a variety of precursor proteins, including pro-hormones and their receptors and adhesion molecules. They are ubiquitously expressed and are involved in many physiological and pathological processes. ...

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Age‐dependent variations of human and rat colon myofibroblasts in culture: Influence on their functional interactions with colon cancer cells

Pourreyron

Dumortier

Ratineau

et al. 2003

Intl Journal of Cancer

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Epithelial-mesenchymal interactions play a pivotal role in colon cancer invasion and metastasis. We aimed at elucidating the impact of long-term cultivation on the phenotypic and functional characteristics of primary fibroblasts and their interaction with the human colon adenocarcinoma cell line LoVoC5. We used fibroblasts from human colon tumor tissue, normal human colon mucosa, rat normal colon and 2 rat colon-derived myofibroblast cell lines, MIC316 and MG. The following parameters were studied: cell shape and size, growth curve, intermediate filament expression and extracellular matrix synthesis. Coculture models with or without cell contacts were used to test the effects on LoVoC5 cell proliferation, spreading and adhesion. Irrespective of their origin, fibroblastic cells in primary cultures presented marked phenotypic and functional changes with time. Before passage 5, they presented as large, slow-growing cells expressing vimentin and ␣-smooth muscle actin; synthesizing laminin-1, fibronectin and collagens I and IV; and inducing LoVoC5 proliferation, spreading and adhesion. After passage 15, they presented as small, fast-growing cells inconstantly expressing ␣-smooth muscle actin and synthesizing mainly type I collagen. In coculture with or without cell contacts, they inhibited LoVoC5 proliferation and allowed only limited cell spreading and adhesion. Myofibroblastic cell lines presented as large, fast-growing cells expressing vimentin and ␣-smooth muscle actin and synthesizing mainly type I collagen. They had no significant effects on LoVoC5 proliferation, spreading and adhesion. Our results underline the importance of age-dependent variations in colon mesenchymal cells in culture and for the in vitro study of epithelial-mesenchymal interactions in colon cancer.

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Site-Specific Epithelial-Mesenchymal Interactions in Digestive Neuroendocrine Tumors

Cited by 17 publications

References 36 publications

Reduction of Menin Expression Enhances Cell Proliferation and Is Tumorigenic in Intestinal Epithelial Cells

Reduction of Menin Expression Enhances Cell Proliferation and Is Tumorigenic in Intestinal Epithelial Cells

Inhibition of Proprotein Convertases Enhances Cell Migration and Metastases Development of Human Colon Carcinoma Cells in a Rat Model

Age‐dependent variations of human and rat colon myofibroblasts in culture: Influence on their functional interactions with colon cancer cells

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