Arachidonic acid and calcium signals in human breast tumor-derived endothelial cells: a proteomic study

Abstract

Intracellular calcium signals activated by growth factors in endothelial cells during angiogenesis regulate cytosolic and nuclear events involved in survival, proliferation and motility. Among the intracellular messengers released upon proangiogenic stimulation, arachidonic acid (AA) and its metabolites play a key role, and their effects are strictly related to calcium homeostasis. In human breast tumor-derived endothelial cells (B-TECs) AA stimulates proliferation and tubulogenesis in a calcium-dependent way. Here, to characterize the proteins whose expression is regulated by AA-induced calcium entry, we used a proteomic approach (two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization mass spectrometry, 2-DE and MALDI-MS) and we compared the proteomes of B-TECs stimulated with AA in presence or in absence of calcium entry (with addition to the culture medium of the calcium chelator EGTA, which completely prevents calcium fluxes throughout the plasma membrane). We found that six proteins increased their levels of expression, all higher when AA-induced calcium entry was abolished. These proteins have been identified by mass spectrometry and database search, and their potential roles in AA-stimulated pathway and in angiogenesis are discussed.

Keywords::

• Angiogenesis
• arachidonic acid
• calcium
• endothelial cells
• 2-DE
• proteomics

Acknowledgements

We thank Dr Benedetta Bussolati (Department of Internal Medicine, University of Torino) for kindly providing us with B-TECs and Dr Alessandra Fiorio Pla (Department of Animal and Human Biology, University of Torino) for critical reading of the manuscript.

Declaration of interest: The work was supported by Italian Ministry of University and Research (MIUR), Ricerca Scientifica Applicata Sanità Piemonte.