Open Access Highly Accessed Research article

Correlation between Slug transcription factor and miR-221 in MDA-MB-231 breast cancer cells

Elisabetta Lambertini1, Andrea Lolli1, Federica Vezzali1, Letizia Penolazzi1, Roberto Gambari2 and Roberta Piva1*

Author affiliations

1 Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, 44121, Italy

2 Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, 44121, Italy

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Citation and License

BMC Cancer 2012, 12:445  doi:10.1186/1471-2407-12-445

Published: 2 October 2012

Abstract

Background

Breast cancer and its metastatic progression is mainly directed by epithelial to mesenchymal transition (EMT), a phenomenon supported by specific transcription factors and miRNAs.

Methods

In order to investigate a possible correlation between Slug transcription factor and miR-221, we performed Slug gene silencing in MDA-MB-231 breast cancer cells and evaluated the expression of genes involved in supporting the breast cancer phenotype, using qRT-PCR and Western blot analysis. Chromatin immunoprecipitation and wound healing assays were employed to determine a functional link between these two molecules.

Results

We showed that Slug silencing significantly decreased the level of miR-221 and vimentin, reactivated Estrogen Receptor α and increased E-cadherin and TRPS1 expression. We demonstrated that miR-221 is a Slug target gene, and identified a specific region of miR-221 promoter that is transcriptionally active and binds the transcription factor Slug “in vivo”. In addition, we showed that in Slug-silenced cells, wich retained residual miR-221 (about 38%), cell migration was strongly inhibited. Cell migration was inhibited, but to a less degree, following complete knockdown of miR-221 expression by transfection with antagomiR-221.

Conclusions

We report for the first time evidence of a correlation between Slug transcription factor and miR-221 in breast cancer cells. These studies suggest that miR-221 expression is, in part, dependent on Slug in breast cancer cells, and that Slug plays a more important role than miR-221 in cell migration and invasion.

Keywords:
Slug; miR-221; Epithelial mesenchymal transition; Breast cancer