title: Enhanced Orai1 and STIM1 expression as well as store operated Ca2+ entry in therapy resistant ovary carcinoma cells.
abstract: Mechanisms underlying therapy resistance of tumor cells include protein kinase Akt. Putative Akt targets include store-operated Ca(2+)-entry (SOCE) accomplished by pore forming ion channel unit Orai1 and its regulator STIM1. We explored whether therapy resistant (A2780cis) differ from therapy sensitive (A2780) ovary carcinoma cells in Akt, Orai1, and STIM1 expression, Ca(2+)-signaling and cell survival following cisplatin (100 µM) treatment. Transcript levels were quantified with RT-PCR, protein abundance with Western blotting, cytosolic Ca(2+)-activity ([Ca(2+)]i) with Fura-2-fluorescence, SOCE from increase of [Ca(2+)]i following Ca(2+)-readdition after Ca(2+)-store depletion, and apoptosis utilizing flow cytometry. Transcript levels of Orai1 and STIM1, protein expression of Orai1, STIM1, and phosphorylated Akt, as well as SOCE were significantly higher in A2780cis than A2780 cells. SOCE was decreased by Akt inhibitor III (SH-6, 10 µM) in A2780cis but not A2780 cells and decreased in both cell lines by Orai1 inhibitor 2-aminoethoxydiphenyl borate (2-ABP, 50 µM). Phosphatidylserine exposure and late apoptosis following cisplatin treatment were significantly lower in A2780cis than A2780 cells, a difference virtually abolished by SH-6 or 2-ABP. In conclusion, Orai1/STIM1 expression and function are increased in therapy resistant ovary carcinoma cells, a property at least in part due to enhanced Akt activity and contributing to therapy resistance in those cells.
authors.affiliation: Department of Physiology, University of Tübingen, D72076 Tübingen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schmidt
authors.forename: Guoxing
authors.initials: G
authors.lastname: Liu
authors.forename: Guilai
authors.initials: G
authors.lastname: Liu
authors.forename: Wenting
authors.initials: W
authors.lastname: Yang
authors.forename: Sabina
authors.initials: S
authors.lastname: Honisch
authors.forename: Stavros
authors.initials: S
authors.lastname: Pantelakos
authors.forename: Christos
authors.initials: C
authors.lastname: Stournaras
authors.forename: Arnd
authors.initials: A
authors.lastname: Hönig
authors.affiliation: Department of Physiology, University of Tübingen, D72076 Tübingen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001549:Benzamides / Q000494:pharmacology; D015153:Blotting, Western; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002945:Cisplatin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D017874:Immediate-Early Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D000071740:ORAI1 Protein; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010716:Phosphatidylinositols / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071737:Stromal Interaction Molecule 1; D000099184:Serum-Glucocorticoid Regulated Kinases
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D001896:Boron Compounds; D002118:Calcium; D015220:Calcium Channels; D002945:Cisplatin; D006834:Hydrazines; D017874:Immediate-Early Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; D010716:Phosphatidylinositols; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D000071737:Stromal Interaction Molecule 1; D000099184:Serum-Glucocorticoid Regulated Kinases; C569030:EMD 638683; C510746:ORAI1 protein, human; C516024:SH-6 compound; C103530:STIM1 protein, human; C109986:2-aminoethoxydiphenyl borate