The Motility and Mesenchymal Features of Breast Cancer Cells Correlate with the Levels and Intracellular Localization of Transglutaminase Type 2.

Nicoletta Bianchi,Stefano Volinia,Silvia Grassilli,Valeria Bertagnolo,Carlo M Bergamini,Gianluca Aguiari,Karine Bourgeois,Federica Brugnoli,Jeffrey W Keillor

doi:10.3390/cells10113059

Nicoletta Bianchi, Stefano Volinia + Show 7 more

Open Access

https://doi.org/10.3390/cells10113059

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Journal: Cells	Publication Date: Nov 6, 2021
Citations: 9	License type: CC BY 4.0

Affiliation: University of Ferrara, University of Ottawa

Abstract

We have investigated motility in breast cancer cell lines in association with the expression of Transglutaminase type 2 (TG2) as well as upon the administration of Doxorubicin (Dox), an active cytotoxic agent that is employed in chemotherapy. The exposure of MCF-7 cells to the drug increased TG2 levels, triggering epithelial–mesenchymal transition (EMT), thereby supporting cell motility. The effects of Dox on the movement of MCF-7 cells were counteracted by treatment with NC9, a TG2 inhibitor, which induced morphological changes and also reduced the migration of MDA-MB-231 cells exhibiting high levels of TG2. The physical association of TG2 with the cytoskeletal component vimentin appeared pivotal both in drug-treated MCF-7 and in MDA-MB-231 cells and seemed to be independent of the catalytic activity of TG2. NC9 altered the subcellular distribution of TG2 and, consequently, the co-localization of TG2 with vimentin. Furthermore, NC9 induced a nuclear accumulation of TG2 as a prelude to TG2-dependent gene expression modifications. Since enzyme activity can affect both motility and nuclear functions, targeting of this protein could represent a method to improve therapeutic interventions in breast tumors, particularly those to control progression and to limit drug resistance.

Highlights

Breast cancer (BrCa) represents a treatable tumor, many phenotypes still escape therapeutic control with relapses and aggressive features in correlation with histopathological grading
Breast tumor cells with an ER positive phenotype, such as MCF-7 cells, express TG2 at low levels, these levels are still high enough to trigger epithelial–mesenchymal transition (EMT) via Snail, Twist, and Hippo. This pathway leads to a decrease of the epithelial marker E-cadherin and increases the mesenchymal marker vimentin [10], which belongs to the pattern of genes that is dysregulated by Snail in cells that are resistant to several drugs, such as Paclitaxel, Docetaxel, and Dox [11]
We aimed to investigate the relationships between TG2 and motility in breast tumor cells in greater detail, focusing on vimentin, which represents an important element of the filamentous cytoskeleton and a pivotal marker of EMT [18]

Summary

Introduction

Breast cancer (BrCa) represents a treatable tumor, many phenotypes still escape therapeutic control with relapses and aggressive features in correlation with histopathological grading. NF-κB forms a positive feedback loop with TG2 that is responsible for the overexpression of TG2 [4] In this context, the triple-negative phenotype MDA-MB-231 cells highly express the enzyme because the TGM2 gene promoter is completely demethylated [5]. Breast tumor cells with an ER positive phenotype, such as MCF-7 cells, express TG2 at low levels, these levels are still high enough to trigger EMT via Snail, Twist, and Hippo This pathway leads to a decrease of the epithelial marker E-cadherin and increases the mesenchymal marker vimentin [10], which belongs to the pattern of genes that is dysregulated by Snail in cells that are resistant to several drugs, such as Paclitaxel, Docetaxel, and Dox [11]. As this network is strongly interconnected to TG2 [3], the levels of this enzyme appear to be much higher in cervical cancer HeLa cells after treatment with Dox [12]

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