Characterization of spontaneous and TGF-β-induced cell motility of primary human normal and neoplastic mammary cells in vitro using novel real-time technology

PLoS One. 2013;8(2):e56591. doi: 10.1371/journal.pone.0056591. Epub 2013 Feb 14.

Abstract

The clinical complications derived from metastatic disease are responsible for the majority of all breast cancer related deaths. Since cell migration and invasion are a prerequisite for metastasis their assessment in patient cancer cells in vitro may have prognostic value for the tumor's metastatic capacity. We employed real-time cell analysis (RTCA) on the xCELLigence DP system to determine in vitro motility of patient-derived primary human breast cancer epithelial cells (HBCEC). Initially, the RTCA assay was validated using established human breast cancer cell lines with either an invasive (MDA-MB-231, MDA-MB-435s) or a non-invasive phenotype (MCF-7, MDA-MB-468), and primary NSCLC cells (Tu459). Previous standard assays of cell migration/invasion revealed that only MDA-MB-231, -435s, and Tu459 cells exhibited spontaneous and TGF-β1-stimulated migration and invasion through a Matrigel barrier. In the present study, the TGF-β1-stimulated activities could be blocked by SB431542, a potent kinase inhibitor of the TGF-β type I receptor ALK5. Application of the RTCA assay to patient-derived tumor cells showed that 4/4 primary HBCEC and primary NSCLC cells, but not normal human mammary epithelial cells (HMEC), displayed high spontaneous migratory and invasive activity which correlated with higher MMP-2 expression and uPA protein levels in HBCEC compared to HMEC. Upon treatment with TGF-β1, HBCEC exhibited morphologic and gene regulatory alterations indicative of epithelial-to-mesenchymal transition. However, exclusively the invasive but not the migratory activity of HBCEC was further enhanced by TGF-β1. This indicates the requirement for molecular, e.g. integrin interactions with Matrigel components in HBCEC in order to become responsive to pro-invasive TGF-β effects. Together, these results show for the first time that tumorigenic HBCEC but not normal HMEC possess a strong basal migratory as well as a basal and TGF-β1-inducible invasive potential. These findings qualify the RTCA assay as an in vitro migration/invasion testing system for patient-specific primary breast cancer cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast / cytology*
  • Breast Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Movement / drug effects*
  • Cytological Techniques / methods*
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Epithelial-Mesenchymal Transition / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Kinetics
  • Matrix Metalloproteinase 2 / genetics
  • Neoplasm Invasiveness
  • Plasminogen Activator Inhibitor 1 / metabolism
  • Time Factors
  • Transforming Growth Factor beta / pharmacology*
  • Urokinase-Type Plasminogen Activator / metabolism

Substances

  • Plasminogen Activator Inhibitor 1
  • Transforming Growth Factor beta
  • Urokinase-Type Plasminogen Activator
  • Matrix Metalloproteinase 2

Grants and funding

This work was sponsored in part by the Niedersächsische Krebshilfe (awarded to Ralf Hass). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.