References of "Polette, Myriam"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailFhit regulates EMT targets through an EGFR/Src/ERK/Slug signaling axis in human bronchial cells.
Joannes, Audrey; Grelet, Simon; Duca, Laurent et al

in Molecular Cancer Research (2014), 12(5), 775-83

In many cancers, including lung carcinomas, Fragile histidine triad (Fhit) is frequently decreased or lost. Fhit status has recently been shown to be associated with elevated in vitro and in vivo ... [more ▼]

In many cancers, including lung carcinomas, Fragile histidine triad (Fhit) is frequently decreased or lost. Fhit status has recently been shown to be associated with elevated in vitro and in vivo invasiveness in lung cancer. Tumor cell invasion is facilitated by epithelial-mesenchymal transition (EMT), a process by which tumor cells lose their epithelial features to acquire a mesenchymal cell-like phenotype. In this study, the mechanism underlying Fhit-regulated EMT was deciphered. Using Slug knockdown, pharmacologic inhibitors PD98059, PP1, and gefitinib as well as an anti-EGFR antibody, it was demonstrated that Fhit silencing in bronchial cells induced overexpression of two primary EMT-associated targets, MMP-9 and vimentin, to regulate cell invasion dependent on an EGFR/Src/ERK/Slug signaling pathway. Moreover, ectopic expression of Fhit in Fhit-deficient lung cancer cells downregulated this pathway. Finally, an inverse correlation was observed between Fhit and phospho-EGFR levels in a cohort of human squamous cell lung carcinoma specimens. These results demonstrate a Fhit-dependent mechanism in the control of EMT-regulated EGFR signaling. IMPLICATIONS: This study adds new insight into the regulatory mechanism of EMT, a process known to increase resistance to conventional and targeted therapies in lung cancer. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailRegulation of membrane-type 1 matrix metalloproteinase expression by zonula occludens-2 in human lung cancer cells.
Luczka, E.; Syne, Laïdya ULg; Nawrocki-Raby, B. et al

in Clinical & Experimental Metastasis (2013)

During tumor invasion, tumor epithelial cells acquire migratory and invasive properties involving important phenotypic alterations. Among these changes, one can observe reorganization or a loss of cell ... [more ▼]

During tumor invasion, tumor epithelial cells acquire migratory and invasive properties involving important phenotypic alterations. Among these changes, one can observe reorganization or a loss of cell-cell adhesion complexes such as tight junctions (TJs). TJs are composed of transmembrane proteins (occludin, claudins) linked to the actin cytoskeleton through cytoplasmic adaptor molecules including those of the zonula occludens family (ZO-1, -2, -3). We here evaluated the potential role of ZO-2 in the acquisition of invasive properties by tumor cells. In vivo, we showed a decrease of ZO-2 expression in bronchopulmonary cancers, with a preferential localization in the cytoplasm. In addition, in vitro, the localization of ZO-2 varied according to invasive properties of tumor cells, with a cytoplasmic localization correlating with invasion. In addition, we demonstrated that ZO-2 inhibition increases invasive and migrative capacities of invasive tumor cells. This was associated with an increase of MT1-MMP. These results suggest that ZO-2, besides its structural role in tight junction assembly, can act also as a repressor of tumor progression through its ability to reduce the expression of tumor-promoting genes in invasive tumor cells. [less ▲]

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailVimentin expression predicts the occurrence of metastases in non small cell lung carcinomas.
Dauphin, Maryline; Barbe, Coralie; Lemaire, Sarah et al

in Lung Cancer (2013), 81(1), 117-22

Epithelial-to-mesenchymal transition (EMT) is believed to contribute to tumour invasion. Vimentin expression by carcinoma cells is a largely recognized marker of EMT. This study aimed at examining ... [more ▼]

Epithelial-to-mesenchymal transition (EMT) is believed to contribute to tumour invasion. Vimentin expression by carcinoma cells is a largely recognized marker of EMT. This study aimed at examining vimentin expression in non small cell lung carcinomas (NSCLC) by immunohistochemistry to evaluate potential correlations between vimentin expression and the differentiation status, the TNM stage and the outcome of the patients. 295 NSCLC including 164 squamous cell carcinomas (SCC), 108 adenocarcinomas (AC) and 23 other NSCLC carcinomas have been examined by immunohistochemistry. Vimentin was indeed detected in 145 cases (49.2%). It was principally present in isolated tumour cells and invasive clusters, particularly in cells at the tumour/stroma interface. Vimentin expression was significantly more expressed in large cell neuroendocrine, adeno-squamous and sarcomatoid carcinomas than in SCC and AC and was significantly associated with the differentiation status of carcinomas. The follow-up of 193 patients further demonstrated that an extensive expression of vimentin (>50% of tumour cells) was associated with the occurrence of metastases. In conclusion, our data demonstrate that vimentin expression is a frequent event in NSCLC and that its expression can be associated with a lack of differentiation and the occurrence of metastases. [less ▲]

Detailed reference viewed: 10 (3 ULg)
Full Text
Peer Reviewed
See detailA dynamic in vivo model of epithelial-to-mesenchymal transitions in circulating tumor cells and metastases of breast cancer.
Bonnomet, Arnaud; Syne, Laïdya ULg; Brysse, Anne ULg et al

in Oncogene (2012), 31(33), 3741-53

Epithelial-to-mesenchymal transition (EMT) processes endow epithelial cells with enhanced migratory/invasive properties and are therefore likely to contribute to tumor invasion and metastatic spread ... [more ▼]

Epithelial-to-mesenchymal transition (EMT) processes endow epithelial cells with enhanced migratory/invasive properties and are therefore likely to contribute to tumor invasion and metastatic spread. Because of the difficulty in following EMT processes in human tumors, we have developed and characterized an animal model with transplantable human breast tumor cells (MDA-MB-468) uniquely showing spontaneous EMT events to occur. Using vimentin as a marker of EMT, heterogeneity was revealed in the primary MDA-MB-468 xenografts with vimentin-negative and vimentin-positive areas, as also observed on clinical human invasive breast tumor specimens. Reverse transcriptase-PCR after microdissection of these populations from the xenografts revealed EMT traits in the vimentin-positive zones characterized by enhanced 'mesenchymal gene' expression (Snail, Slug and fibroblast-specific protein-1) and diminished expression of epithelial molecules (E-cadherin, ZO-3 and JAM-A). Circulating tumor cells (CTCs) were detected in the blood as soon as 8 days after s.c. injection, and lung metastases developed in all animals injected as examined by in vivo imaging analyses and histology. High levels of vimentin RNA were detected in CTCs by reverse transcriptase-quantitative PCR as well as, to a lesser extent, Snail and Slug RNA. Von Willebrand Factor/vimentin double immunostainings further showed that tumor cells in vascular tumoral emboli all expressed vimentin. Tumoral emboli in the lungs also expressed vimentin whereas macrometastases displayed heterogenous vimentin expression, as seen in the primary xenografts. In conclusion, our data uniquely demonstrate in an in vivo context that EMT occurs in the primary tumors, and associates with an enhanced ability to intravasate and generate CTCs. They further suggest that mesenchymal-to-epithelial phenomena occur in secondary organs, facilitating the metastatic growth [less ▲]

Detailed reference viewed: 47 (7 ULg)
Full Text
Peer Reviewed
See detailRegulation of CXCL8/IL-8 expression by Zonula Occludens-1 in human breast cancer cells.
Brysse, Anne ULg; Mestdagt, Mélanie ULg; Polette, Myriam et al

in Molecular Cancer Research (2012), 10(1), 121-32

Accumulating data now suggest that ZO-1, once delocalized from tight junctions, could be implicated in the regulation of tumor promoting genes. Because of their major implication in different steps of ... [more ▼]

Accumulating data now suggest that ZO-1, once delocalized from tight junctions, could be implicated in the regulation of tumor promoting genes. Because of their major implication in different steps of tumor progression, we investigated here the influence of ZO-1 on chemokines expression in breast cancer cells. Using GeneArray analysis to compare chemokine mRNA expression in breast tumor cells transfected with a siRNA against ZO-1, we identified CXCL-8/IL-8 as a major potential target of ZO-1 signaling, being strongly downregulated following ZO-1 siRNA transfection. Examining further the relationship between ZO-1 and IL-8, we first demonstrated that CXCL8/IL-8 expression correlates with a relocalization of ZO-1 in several breast cancer cell lines. Moreover, CXCL8/IL-8 is downregulated in invasive BT549 cells transfected with 3 different ZO-1 siRNA and overexpressed in non-invasive BT20 and SKBR3 cells transfected with vectors expressing ZO-1. We also provide evidence for an activation of the CXCL8/IL-8 promoter by ZO-1. Finally, we demonstrate that the regulation of CXCL8/IL-8 by ZO-1 is independent of the beta-catenin pathway. Our results thus clearly demonstrate an implication of ZO-1 in CXCL8/IL-8 regulation. Because of the major implications of CXCL8/IL-8 in tumor invasion, such a regulation could play an important role in breast cancer progression. [less ▲]

Detailed reference viewed: 91 (14 ULg)
Full Text
Peer Reviewed
See detailQuantitative cell dispersion analysis: new test to measure tumor cell aggressiveness
Nawrocki-Raby, Béatrice; Polette, Myriam; Gilles, Christine ULg et al

in International Journal of Cancer = Journal International du Cancer (2001), 93(5), 644-52

Tumor progression requires the dispersion of epithelial cells from neoplastic clusters and cell invasion of adjacent stromal connective tissue. Aiming at demonstrating the precise relationships between ... [more ▼]

Tumor progression requires the dispersion of epithelial cells from neoplastic clusters and cell invasion of adjacent stromal connective tissue. Aiming at demonstrating the precise relationships between cell dispersion and cell invasion, related respectively to expression of E-cadherin/catenin complex and matrix metalloproteinases (MMPs), we developed an original in vitro model of cell dispersion analysis. Our study reports the validation of this model that allowed us to analyze and quantify the cell cohesion level by means of time-lapse videomicroscopy and computer analysis based on the observation of spatial and temporal cell distribution. Our model was able to distinguish 2 groups among different human bronchial and mammary epithelial cells previously characterized for the expression of E-cadherin/catenin complex and MMPs and their invasive capacity in the Boyden chamber assay. The first group (16HBE14o-, MCF-7, T47D) that expressed membranous E-cadherin and -catenin, and was negative for MMP-2 expression and non-invasive, displayed a highly cohesive pattern corresponding to a cluster spatial distribution. The second group (Beas2B, BZR, BZR-T33, MDA-MB-231, MDA-MB-435, BT549 and HS578T) that was invasive and showed lack of expression of E-cadherin and a cytoplasmic redistribution of -catenin, displayed a dispersed pattern corresponding to a random spatial distribution. Downregulation of E-cadherin by a blocking antibody induced a more random distribution. Conversely, expression of E-cadherin by cDNA transfection induced a cluster distribution. Moreover, tumor cell lines that co-expressed MT1-MMP and MMP-2 (Beas2B, BZR, BZR-T33, MDA-MB-435, BT549 and HS578T) showed a more dispersed pattern than tumor cell lines that did not express MMP-2 (MDA-MB-231). In conclusion, we demonstrated that the spatial group behavior of cell lines, i.e., their cohesion/dispersion ability, reflects their invasive properties. Thus, this model of cell dispersion analysis may represent a new test to measure tumor cell aggressiveness. [less ▲]

Detailed reference viewed: 25 (10 ULg)
Peer Reviewed
See detailExpression of gelatinases A and B and their tissue inhibitors by cells of early and term human placenta and gestational endometrium
Polette, Myriam; Nawrocki, B.; PINTIAUX, Axelle ULg et al

in Laboratory Investigation : Journal of Technical Methods & Pathology (1994), 71(6), 838-846

BACKGROUND: Human placentation is mediated by fetal trophoblastic cells that invade the maternal uterine endometrium. Trophoblast invasion requires a precisely regulated secretion of specific proteolytic ... [more ▼]

BACKGROUND: Human placentation is mediated by fetal trophoblastic cells that invade the maternal uterine endometrium. Trophoblast invasion requires a precisely regulated secretion of specific proteolytic enzymes able to degrade the endometrial basement membrane and extracellular matrix. EXPERIMENTAL DESIGN: Several studies have documented the key roles of matrix metalloproteinases and their tissue inhibitors in the invasion of various matrices by cultured trophoblasts. In vitro studies suggest that placentation could result from a balance between the secretion of these enzymes by trophoblast cells and their inhibition by the natural tissue inhibitors (TIMPs) produced by maternal decidual cells. The precise localization and levels of expression of these proteins that account for and control invasion during human placentation in vivo however, have not been described. We have evaluated, in vivo, by immunohistochemistry, Northern blot analysis and in situ hybridization, the expression of two metalloproteinases (gelatinases A and B) and their two tissue inhibitors (TIMPs 1 and 2) in placental villi and placental beds of first and third trimesters of normal pregnancy. RESULTS: Human first trimester intermediate trophoblast produced both gelatinases A and B; these two gelatinases were respectively less and no more detected at term in these cells. We found that both TIMP1 and 2 were also expressed in maternal decidual cells with a dramatic increase of TIMP1 at the term of pregnancy. In floating villi, gelatinase A and TIMP1 were localized in the stromal compartment, whereas gelatinase B and TIMP2 were codistributed in trophoblast cells. CONCLUSIONS: The gelatinases A and B and their tissue inhibitors are thus expressed by specific cells in early and late placental beds and villi. This pattern of expression varies during pregnancy. Therefore, our morphologic study supports biologic findings suggesting that these proteins may participate in placentation. [less ▲]

Detailed reference viewed: 12 (2 ULg)