Regulation of membrane-type 1 matrix metalloproteinase expression by zonula occludens-2 in human lung cancer cells.
; Syne, Laïdya ; 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)
Regulation of CXCL8/IL-8 expression by Zonula Occludens-1 in human breast cancer cells.
Brysse, Anne ; Mestdagt, Mélanie ; 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)