Glypican-3 induces a mesenchymal to epithelial transition in human breast cancer cells.

Lilian Fedra Castillo,Ancely Ferreira Dos Santos,Gisela Novack,Ana María Cabanillas,María Candelaria Llorens,María Giselle Peters,Elisa Bal De Kier Joffé,María Amparo Lago Huvelle,Rocío Tascón,Jorge Shortrede,Leticia Labriola

doi:10.18632/oncotarget.11107

Abstract

Breast cancer is the disease with the highest impact on global health, being metastasis the main cause of death. To metastasize, carcinoma cells must reactivate a latent program called epithelial-mesenchymal transition (EMT), through which epithelial cancer cells acquire mesenchymal-like traits.Glypican-3 (GPC3), a proteoglycan involved in the regulation of proliferation and survival, has been associated with cancer. In this study we observed that the expression of GPC3 is opposite to the invasive/metastatic ability of Hs578T, MDA-MB231, ZR-75-1 and MCF-7 human breast cancer cell lines. GPC3 silencing activated growth, cell death resistance, migration, and invasive/metastatic capacity of MCF-7 cancer cells, while GPC3 overexpression inhibited these properties in MDA-MB231 tumor cell line. Moreover, silencing of GPC3 deepened the MCF-7 breast cancer cells mesenchymal characteristics, decreasing the expression of the epithelial marker E-Cadherin. On the other side, GPC3 overexpression induced the mesenchymal-epithelial transition (MET) of MDA-MB231 breast cancer cells, which re-expressed E-Cadherin and reduced the expression of vimentin and N-Cadherin. While GPC3 inhibited the canonical Wnt/β-Catenin pathway in the breast cancer cells, this inhibition did not have effect on E-Cadherin expression. We demonstrated that the transcriptional repressor of E-Cadherin - ZEB1 - is upregulated in GPC3 silenced MCF-7 cells, while it is downregulated when GPC3 was overexpressed in MDA-MB231 cells. We presented experimental evidences showing that GPC3 induces the E-Cadherin re-expression in MDA-MB231 cells through the downregulation of ZEB1.Our data indicate that GPC3 is an important regulator of EMT in breast cancer, and a potential target for procedures against breast cancer metastasis.

Highlights

Breast cancer is the leading cause of female mortality due to malignant diseases worldwide [1]
We demonstrated that the transcriptional repressor of E-Cadherin - ZEB1 - is upregulated in GPC3 silenced MCF-7 cells, while it is downregulated when GPC3 was overexpressed in MDA-MB231 cells
We previously showed that the ectopic expression of GPC3 in the LM3 murine mammary adenocarcinoma cell line was able to inhibit invasion and metastasis [28]

Summary

Introduction

Breast cancer is the leading cause of female mortality due to malignant diseases worldwide [1]. EMT marks the first step of the “metastasis cascade”, where epithelial cells of the primary tumor acquire mesenchymal-like traits. This way, epithelial cells lose their cell-cell adhesion and apical-basal polarity and change to a fibroblastic phenotype, modulate the organization of their cytoskeleton and gain the ability to migrate individually and invade basement membrane and blood vessels. Upon intravasation these cells stay in the bloodstream as circulating tumor cells, until they exit at some distant organs to initiate their colonization [3, 4]. Epithelial cells that undergo the EMT lose epithelial markers expression - such as E-Cadherin while they acquire mesenchymal ones, like vimentin and N-Cadherin [5]

Methods

Results

Conclusion