Remodeling of purinergic receptor-mediated Ca 2+ signaling as a consequence of EGF-induced epithelial-mesenchymal transition in breast cancer cells

Felicity M. Davis, Paraic A. Kenny, Eliza T.L. Soo, Bryce J.W. van Denderen, Erik W. Thompson, Peter J. Cabot, Marie Odile Parat, Sarah J. Roberts-Thomson, Gregory R. Monteith

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Background: The microenvironment plays a pivotal role in tumor cell proliferation, survival and migration. Invasive cancer cells face a new set of environmental challenges as they breach the basement membrane and colonize distant organs during the process of metastasis. Phenotypic switching, such as that which occurs during epithelial-mesenchymal transition (EMT), may be associated with a remodeling of cell surface receptors and thus altered responses to signals from the tumor microenvironment. Methodology/Principal Findings: We assessed changes in intracellular Ca 2+ in cells loaded with Fluo-4 AM using a fluorometric imaging plate reader (FLIPR TETRA) and observed significant changes in the potency of ATP (EC 50 0.175 μM (-EGF) versus 1.731 μM (+EGF), P<0.05), and the nature of the ATP-induced Ca 2+ transient, corresponding with a 10-fold increase in the mesenchymal marker vimentin (P<0.05). We observed no change in the sensitivity to PAR2-mediated Ca 2+ signaling, indicating that these alterations are not simply a consequence of changes in global Ca 2+ homeostasis. To determine whether changes in ATP-mediated Ca 2+ signaling are preceded by alterations in the transcriptional profile of purinergic receptors, we analyzed the expression of a panel of P2X ionotropic and P2Y metabotropic purinergic receptors using real-time RT-PCR and found significant and specific alterations in the suite of ATP-activated purinergic receptors during EGF-induced EMT in breast cancer cells. Our studies are the first to show that P2X 5 ionotropic receptors are enriched in the mesenchymal phenotype and that silencing of P2X 5 leads to a significant reduction (25%, P<0.05) in EGF-induced vimentin protein expression. Conclusions: The acquisition of a new suite of cell surface purinergic receptors is a feature of EGF-mediated EMT in MDA-MB-468 breast cancer cells. Such changes may impart advantageous phenotypic traits and represent a novel mechanism for the targeting of cancer metastasis.

Original languageEnglish (US)
Article numbere23464
JournalPloS one
Volume6
Issue number8
DOIs
StatePublished - 2011

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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    Davis, F. M., Kenny, P. A., Soo, E. T. L., van Denderen, B. J. W., Thompson, E. W., Cabot, P. J., Parat, M. O., Roberts-Thomson, S. J., & Monteith, G. R. (2011). Remodeling of purinergic receptor-mediated Ca 2+ signaling as a consequence of EGF-induced epithelial-mesenchymal transition in breast cancer cells. PloS one, 6(8), [e23464]. https://doi.org/10.1371/journal.pone.0023464