Calcium Mobilization in Ovarian Cancer Cells in Response to Lysophospholipids

Intracellular free Ca²⁺ concentration ([Ca²⁺ ]_i ) plays a critical role in regulating many diverse cellular functions including cell proliferation and programmed cell death (apoptosis) (1 ). An elevation in [Ca²⁺ ]_i activates enzymes (phospholipase A₂ , phospho- lipase D and some isoforms of protein kinase C) associated with the liberation of bioactive lipids such as arachidonic acid (AA) and lysophosphatidic acid (LPA) (1 ,2 ). AA and its metabolites have been implicated in multiple steps of carcinogenesis (3 ,4 ). LPA as well as several other bioactive lipids stimulate release of Ca²⁺ from intracellular stores and regulate proliferation of ovarian cancer cells I5-7 ).