Upregulation of Orail and STIM1 expression as well as store-operated Ca~(2+) entry in ovary carcinoma cells by placental growth factor

摘要

Placental growth factor (P1GF) is produced by tumor cells and stimulates tumor growth and metastasis in part by upregulation of hypoxia inducible factor HIF1alpha. Orchestration of tumor cell proliferation and migration involves oscillations of cytosolic Ca~(2+) activity ([Ca~(2+)]j). The [Ca~(2+)]j oscillations could be accomplished by triggering of intracellular Ca~(2+) release followed by store-operated Ca~(2+)-entry (SOCE). Mechanisms accomplishing SOCE include the pore-forming ion channel unit Orail and its regulator STIM1. The present study explored whether P1GF influences the expression of Orail and STIM1, as well as SOCE and whether this effect impacts on HIFla expression.To this end, ovary carcinoma cells were cultured for 24 h without and with P1GF (lOng/ml). Orail, STIMl and HIFla transcript levels were quantified utilizing RT-PCR and Orail, STIM1 and HIFla protein levels by Western blotting. [Ca~(2+)]j was estimated from Fura-2-fluorescence and SOCE from increase of [Ca~(2+)]_i following Ca~(2+) re-addition after Ca~(2+)-store depletion with extracellular Ca~(2+) removal and sar-coendoplasmatic Ca~(2+)-ATPase (SERCA) inhibitor thapsigargin (1 muM).