title: Activation of the calcium-sensing receptor by high calcium induced breast cancer cell proliferation and TRPC1 cation channel over-expression potentially through EGFR pathways.
abstract: The calcium sensing receptor (CaR) is a G-protein-coupled receptor that is activated by extracellular calcium ([Ca(2+)](o)). In MCF-7 human breast cancer cells, we previously reported that treatment with [Ca(2+)](o) for 24h leads to an over-expression of the Transient Receptor Potential Canonical 1 (TRPC1) cation channel and cell proliferation. Both involve the extracellular signal-regulated Kinases 1 & 2 (ERK1/2). MCF-7 also expressed epidermal growth factor receptor (EGFR) which is involved in cell proliferation through ERK1/2. Therefore, we investigated the cross-talk between CaR and EGFR in mediating ERK1/2 phosphorylation, TRPC1 over-expression and cell proliferation. Our data show that both high [Ca(2+)](o) and EGF phosphorylate ERK1/2. Furthermore, inhibition of EGFR kinase and matrix metalloproteinases (MMPs) reduced the overall effects mediated by [Ca(2+)](o) such as activation of ERK1/2, expression of TRPC1 and cell proliferation. They indicate the important role of the CaR-EGFR-ERK axis in transmitting mitogenic signals generated by high [Ca(2+)](o) in MCF-7 cells.
authors.affiliation: Laboratoire de Physiologie Cellulaire et Moléculaire, JE 2530 Canaux Ioniques dans le cancer du sein, Faculté des Sciences, 33 Rue St Leu 80039, Amiens, France.
authors.forename: Yassine
authors.initials: Y
authors.lastname: El Hiani
authors.forename: Vadil
authors.initials: V
authors.lastname: Lehen'kyi
authors.forename: Halima
authors.initials: H
authors.lastname: Ouadid-Ahidouch
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ahidouch