Calcium Mobilization and Inhibition of Akt Reduced the Binding of PEO-1 Cells to Fibronectin

Abstract

Objectives: To investigate the effects of intracellular calcium (Ca2+) mobilization, beta-catenin and Akt signal pathways after the binding of metastatic ovarian cells to fibronectin. Materials and Methods: The expression levels of alpha 4 beta 1 and alpha v beta 6 integrin were determined using alpha 4,beta 1, alpha v, and beta 6 antibodies using flow cytometry on PEO-1 cells. The effect of [Ca2+]i on cell adhesion capacity was investigated using RTCA after stimulating PEO-1 cells using thapsigargin and tunicamycin. The binding rate of PEO-1 cells to fibronectin was also investigated in the presence of either different concentrations of cardamonin, which inhibits the accumulation of beta-catenin, or different concentrations of FPA 124, which is a specific inhibitor for the PKB/Akt signal pathway, using RTCA. Results: RTCA analysis results showed that increasing [Ca2+]i through leakage of the calcium pool was strongly effective on PEO-1 cell binding to fibronectin. Extracellular calcium influx also reduced the binding of PEO-1 cells. Cell binding to fibronectin was also inhibited with a ratio of 64% in the presence of 100 mu M cardamonin compared with untreated control cells. Finally, it was found that PKB/Akt inhibition with 15 mu M FPA 124 decreased the binding of PEO-1 cells to fibronectin with a ratio of 88% compared with untreated control cells. Conclusion: PEO-1 cell binding to fibronectin via integrins could be related to intracellular Ca2+ mobilization and Akt signaling.