Fhit regulates EMT targets through an EGFR/Src/ERK/Slug signaling axis in human bronchial cells.
; ; 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: 2 (0 ULg)
Vimentin expression predicts the occurrence of metastases in non small cell lung carcinomas.
; ; 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)
A dynamic in vivo model of epithelial-to-mesenchymal transitions in circulating tumor cells and metastases of breast cancer.
; Syne, Laïdya ; Brysse, Anne 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)
Quantitative cell dispersion analysis: new test to measure tumor cell aggressiveness
; ; Gilles, Christine 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)