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Boissan M.,University Pierre and Marie Curie | Boissan M.,French Institute of Health and Medical Research | De Wever O.,Laboratory of Experimental Cancer Research | Lizarraga F.,University Pierre and Marie Curie | And 20 more authors.
Cancer Research | Year: 2010

Loss of NM23-H1 expression correlates with the degree of metastasis and with unfavorable clinical prognosis in several types of human carcinoma. However, the mechanistic basis for the metastasis suppressor function of NM23-H1 is obscure. We silenced NM23-H1 expression in human hepatoma and colon carcinoma cells and methodologically investigated effects on cell-cell adhesion, migration, invasion, and signaling linked to cancer progression. NM23-H1 silencing disrupted cell-cell adhesion mediated by E-cadherin, resulting in β-catenin nuclear translocation and T-cell factor/lymphoid-enhancing factor-1 transactivation. Further, NM23-H1 silencing promoted cellular scattering, motility, and extracellular matrix invasion by promoting invadopodia formation and upregulating several matrix metalloproteinases (MMP), including membrane type 1 MMP. In contrast, silencing the related NM23-H2 gene was ineffective at promoting invasion. NM23-H1 silencing activated proinvasive signaling pathways involving Rac1, mitogen-activated protein kinases, phosphatidylinositol 3-kinase (PI3K)/Akt, and src kinase. Conversely, NM23-H1 was dispensable for cancer cell proliferation in vitro and liver regeneration in NM23-M1 null mice, instead inducing cellular resistance to chemotherapeutic drugs in vitro. Analysis of NM23-H1 expression in clinical specimens revealed high expression in premalignant lesions (liver cirrhosis and colon adenoma) and the central body of primary liver or colon tumors, but downregulation at the invasive front of tumors. Our findings reveal that NM23-H1 is critical for control of cell-cell adhesion and cell migration at early stages of the invasive program in epithelial cancers, orchestrating a barrier against conversion of in situ carcinoma into invasive malignancy. ©2010 AACR. Source


Alava P.,Ghent University | Du Laing G.,Ghent University | Tack F.,Ghent University | De Ryck T.,Laboratory of Experimental Cancer Research | Van De Wiele T.,Laboratory of Experimental Cancer Research
Chemosphere | Year: 2015

Arsenic (As) is an important contaminant present in food and water. Several studies have indicated that the occurrence of As based skin lesions is significantly different when root and gourd rich diets are consumed compared to meat rich diets. Additionally, urinary As speciation from orally exposed individuals appears to depend on the composition of the diet. These observations imply that diet composition can affect both the bioavailable As fraction as the As speciation in the body. In this study, we used the in vitro gastrointestinal method (IVG) to evaluate how an Asian type diet (fiber rich) and a Western type diet (fat and protein rich), differ in their capability to release inorganic As (iAsV) and dimethyl arsinate (DMAV) from a rice matrix following gastrointestinal digestion. Moreover, we used a validated dynamic gut simulator to investigate whether diet background affects As metabolism by gut microbiota in a colon environment. An Asian diet background resulted in a larger As bioaccessibility (81.2%) than a Western diet background (63.4%). On the other hand, incubation of As contaminated rice with human colon microbiota in the presence of a Western type diet resulted in a larger amount of hazardous As species - monomethyl arsonite and monomethylmonothio arsonate - to be formed after 48h. The permeability of these As species (60.5% and 50.5% resp.) across a Caco-2 cell line was significantly higher compared to iAsV and DMAV (46.5% and 28% resp.). We conclude that dietary background is a crucial parameter to incorporate when predicting bioavailability with bioaccessibility measurements and when assessing health risks from As following oral exposure. © 2014 Elsevier Ltd. Source


De Boeck A.,Laboratory of Experimental Cancer Research | Hendrix A.,Laboratory of Experimental Cancer Research | Maynard D.,National Human Genome Research Institute | Van Bockstal M.,Ghent University | And 5 more authors.
Proteomics | Year: 2013

The identification of cancer-associated fibroblast (CAF)-derived proteins that mediate interactions between the tumor stroma and cancer cells is a crucial step toward the discovery of new molecular targets for therapy or molecular signatures that improve tumor classification and predict clinical outcome. CAF are α-smooth muscle actin positive, representing a myofibroblast phenotype that may differentiate from multiple precursor cells, including bone marrow-derived mesenchymal stem cells (MSC). Transforming growth factor-β1 (TGF-β1) is a crucial inducer of α-smooth muscle actin positive CAFs. In this study, we aimed to identify CAF-derived regulators of colon cancer progression by performing a high-throughput differential secretome profiling between CAF compared to noncancer-activated bone marrow-derived MSC. In addition, we explored the effect of TGF-β1 on the secretion of proteins by bone marrow-derived MSC in comparison with the protein secretion profile of CAF. TGF-β1 induced de novo secretion of 84 proteins in MSC, of which 16 proteins, including stromal-derived factor-1α and Rantes, were also present in CAF secretome. Immunohistochemistry further validated the expression of selected candidates such as tenascin C, fibronectin ED-A domain and stromal-derived factor-1 in clinical colon cancer specimens. In conclusion, this differential secretome approach enabled us to identify a series of candidate biomarkers for colon cancer that are associated with a CAF-specific phenotype. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Medves S.,Laboratory of Experimental Cancer Research | Auchter M.,Aix - Marseille University | Chambeau L.,Laboratory of Experimental Cancer Research | Gazzo S.,French National Center for Scientific Research | And 15 more authors.
British Journal of Haematology | Year: 2016

Cancer cells protect their telomere ends from erosion through reactivation of telomerase or by using the Alternative Lengthening of Telomere (ALT) mechanism that depends on homologous recombination. Chronic lymphocytic leukaemia (CLL) B cells are characterized by almost no telomerase activity, shelterin deregulation and telomere fusions. To characterize telomeric maintenance mechanisms in B-CLL patients, we measured their telomere length, telomerase expression and the main hallmarks of the ALT activity i.e. C-circle concentration, an extra-chromosomal telomere repeat (ECTR), and the level of telomeric sister chromatid exchange (T-SCE) rate. Patients showed relative homogenous telomere length although almost no TERT transcript and nearly no C-circle were evidenced. Nevertheless, compared with normal B cells, B-CLL cells showed an increase in T-SCE rate that was correlated with a strong down-regulation of the topoisomerase III alpha (TOP3A) expression, involved in the dissolution of Holliday Junctions (HJ), together with an increased expression of SLX1A, SLX4, MUS81 and GEN1, involved in the resolution of HJ. Altogether, our results suggest that the telomere maintenance mechanism of B-CLL cells do not preferentially use telomerase or ALT. Rather, the rupture of the dissolvasome/resolvasome balance may increase telomere shuffling that could homogenize telomere length, slowing telomere erosion in this disease. © 2016 John Wiley & Sons Ltd Source

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