Activation of choline kinase by extracellular Ca2+ is Ca2+-sensing receptor, Gα12 and Rho-dependent in breast cancer cells

Chunfa Huang, Lindsey M. Hydo, Shiguo Liu, R. Tyler Miller

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Breast cancer cell metastases to bone result in osteolysis and release of large quantities of Ca2+ into the bone microenviroment. Extracellular Ca2+ (Cao2+) acting through the Ca2+-sensing receptor (CaR), a member of G protein-coupled receptor superfamily, plays an important role in the regulation of multiple signaling pathways. Here, we find that expression of the CaR and Gα12 is significantly up-regulated in breast cancer cells (MDA-MB-231 and MCF-7) compared with nonmalignant breast cells (Hs 578Bst and MCF-10A). Cao2+ induces a significant increase in extracellular [3H]phosphocholine (P-cho) production in breast cancer cells. Using an anti-CaR antibody to block Cao2+ binding to the CaR and small interfering RNA (siRNA) to silence CaR gene expression, our data demonstrate that [3H]P-cho production in response to Cao2+-stimulation is CaR-dependent. By analyzing cellular lipid profiles and using siRNA to silence choline kinase (ChoK) expression, we determine that the production of [3H]P-cho is primarily related to CaR-induced ChoK activation, and not degradation of choline phospholipids. Finally, by pretreatment of the cells with either pertussis toxin or C3 exoenzyme, co-immunoprecipiation of Gαi, Gαq or Gα12 with the CaR, and RhoA translocation, we found that the enhancement of ChoK activation and P-cho production in breast cancer cells occurs via a CaR-Gα12-Rho signaling pathway.

Original languageEnglish (US)
Pages (from-to)1894-1900
Number of pages7
JournalCellular Signalling
Volume21
Issue number12
DOIs
StatePublished - Dec 1 2009

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Keywords

  • Breast cancer cells
  • Ca-sensing receptor
  • Choline kinase
  • Phosphocholine

ASJC Scopus subject areas

  • Cell Biology

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