Claudin-2 is selectively enriched in and promotes the formation of breast cancer liver metastases through engagement of integrin complexes

Oncogene. 2011 Mar 17;30(11):1318-28. doi: 10.1038/onc.2010.518. Epub 2010 Nov 15.


The liver represents the third most frequent site of metastasis in patients with breast cancer. We performed in vivo selection using 4T1 breast cancer cells to identify genes associated with the liver metastatic phenotype. Coincident with the loss of numerous tight-junctional proteins, we observe claudin-2 overexpression, specifically in liver-aggressive breast cancer cells. We further demonstrate that claudin-2 is both necessary and sufficient for the ability of 4T1 breast cancer cells to colonize and grow in the liver. The liver-aggressive breast cancer cells display a claudin-2-mediated increase in their ability to adhere to extracellular matrix (ECM) components, such as fibronectin and type IV collagen. Claudin-2 facilitates these cell/matrix interactions by increasing the cell surface expression of α(2)β(1)- and α(5)β(1)-integrin complexes in breast cancer cells. Indeed, claudin-2-mediated adhesion to fibronectin and type IV collagen can be blocked with neutralizing antibodies that target α(5)β(1) and α(2)β(1) complexes, respectively. Immunohistochemical analyses reveal that claudin-2, although weakly expressed in primary human breast cancers, is readily detected in all liver metastasis samples examined to date. Together, these results uncover novel roles for claudin-2 in promoting breast cancer adhesion to the ECM and define its importance during breast cancer metastasis to the liver.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms / genetics*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Cell Adhesion
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Cell Membrane / pathology
  • Claudins
  • Extracellular Matrix / metabolism
  • Extracellular Matrix / pathology
  • Female
  • Fibronectins / metabolism
  • Humans
  • Immunohistochemistry
  • Integrin alpha2beta1 / metabolism
  • Integrin alpha5beta1 / metabolism
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / secondary*
  • Membrane Proteins / physiology*


  • CLDN2 protein, human
  • Claudins
  • Fibronectins
  • Integrin alpha2beta1
  • Integrin alpha5beta1
  • Membrane Proteins