The T box transcription factor TBX2 promotes epithelial-mesenchymal transition and invasion of normal and malignant breast epithelial cells

PLoS One. 2012;7(7):e41355. doi: 10.1371/journal.pone.0041355. Epub 2012 Jul 23.


The T box transcription factor TBX2, a master regulator of organogenesis, is aberrantly amplified in aggressive human epithelial cancers. While it has been shown that overexpression of TBX2 can bypass senescence, a failsafe mechanism against cancer, its potential role in tumor invasion has remained obscure. Here we demonstrate that TBX2 is a strong cell-autonomous inducer of the epithelial-mesenchymal transition (EMT), a latent morphogenetic program that is key to tumor progression from noninvasive to invasive malignant states. Ectopic expression of TBX2 in normal HC11 and MCF10A mammary epithelial cells was sufficient to induce morphological, molecular, and behavioral changes characteristic of EMT. These changes included loss of epithelial adhesion and polarity gene (E-cadherin, ß-catenin, ZO1) expression, and abnormal gain of mesenchymal markers (N-cadherin, Vimentin), as well as increased cell motility and invasion. Conversely, abrogation of endogenous TBX2 overexpression in the malignant human breast carcinoma cell lines MDA-MB-435 and MDA-MB-157 led to a restitution of epithelial characteristics with reciprocal loss of mesenchymal markers. Importantly, TBX2 inhibition abolished tumor cell invasion and the capacity to form lung metastases in a Xenograft mouse model. Meta-analysis of gene expression in over one thousand primary human breast tumors further showed that high TBX2 expression was significantly associated with reduced metastasis-free survival in patients, and with tumor subtypes enriched in EMT gene signatures, consistent with a role of TBX2 in oncogenic EMT. ChIP analysis and cell-based reporter assays further revealed that TBX2 directly represses transcription of E-cadherin, a tumor suppressor gene, whose loss is crucial for malignant tumor progression. Collectively, our results uncover an unanticipated link between TBX2 deregulation in cancer and the acquisition of EMT and invasive features of epithelial tumor cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Breast Neoplasms / pathology*
  • Cadherins / genetics
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Down-Regulation / drug effects
  • Epithelial-Mesenchymal Transition* / drug effects
  • Gene Silencing
  • Humans
  • Mammary Glands, Human / cytology*
  • Mammary Glands, Human / drug effects
  • Mammary Glands, Human / metabolism
  • Mammary Glands, Human / pathology*
  • Mice
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • T-Box Domain Proteins / deficiency
  • T-Box Domain Proteins / genetics
  • T-Box Domain Proteins / metabolism*
  • Transcription, Genetic / drug effects
  • Transforming Growth Factor beta / pharmacology


  • Cadherins
  • T-Box Domain Protein 2
  • T-Box Domain Proteins
  • Transforming Growth Factor beta