title: Epi-reevesioside F inhibits Na+/K+-ATPase, causing cytosolic acidification, Bak activation and apoptosis in glioblastoma.
abstract: Epi-reevesioside F, a new cardiac glycoside isolated from the root of Reevesia formosana, displayed potent activity against glioblastoma cells. Epi-reevesioside F was more potent than ouabain with IC50 values of 27.3±1.7 vs. 48.7±1.8 nM (P < 0.001) and 45.0±3.4 vs. 81.3±4.3 nM (P < 0.001) in glioblastoma T98 and U87 cells, respectively. However, both Epi-reevesioside F and ouabain were ineffective in A172 cells, a glioblastoma cell line with low Na+/K+-ATPase α3 subunit expression. Epi-reevesioside F induced cell cycle arrest at S and G2 phases and apoptosis. It also induced an increase of intracellular concentration of Na+ but not Ca2+, cleavage and exposure of N-terminus of Bak, loss of mitochondrial membrane potential, inhibition of Akt activity and induction of caspase cascades. Potassium supplements significantly inhibited Epi-reevesioside F-induced effects. Notably, Epi-reevesioside F caused cytosolic acidification that was highly correlated with the anti-proliferative activity. In summary, the data suggest that Epi-reevesioside F inhibits Na+/K+-ATPase, leading to overload of intracellular Na+ and cytosolic acidification, Bak activation and loss of mitochondrial membrane potential. The PI3-kinase/Akt pathway is inhibited and caspase-dependent apoptosis is ultimately triggered in Epi-reevesioside F-treated glioblastoma cells.
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Jui-Ling
authors.initials: JL
authors.lastname: Hsu
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Fan-Lun
authors.initials: FL
authors.lastname: Liu
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Lih-Ching
authors.initials: LC
authors.lastname: Hsu
authors.affiliation: School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.|Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Hsun-Shuo
authors.initials: HS
authors.lastname: Chang
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Wohn-Jenn
authors.initials: WJ
authors.lastname: Leu
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Yu
authors.affiliation: The Division of Medicinal Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH, USA.
authors.forename: Wei-Ling
authors.initials: WL
authors.lastname: Chang
authors.affiliation: School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.|Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ih-Sheng
authors.initials: IS
authors.lastname: Chen
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Fan-Lu
authors.initials: FL
authors.lastname: Kung
authors.affiliation: School of Pharmacy, National Taiwan University, Taipei, Taiwan.
authors.forename: Jih-Hwa
authors.initials: JH
authors.lastname: Guh
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry; D017209:Apoptosis / Q000187:drug effects*; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D002118:Calcium / Q000737:chemistry; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003600:Cytosol / Q000378:metabolism; D005434:Flow Cytometry; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D020128:Inhibitory Concentration 50; D053078:Membrane Potential, Mitochondrial; D010042:Ouabain / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry; D017434:Protein Structure, Tertiary; D012235:Rhodamines / Q000737:chemistry; D012503:Saponins / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C494772:BAK1 protein, human; D012235:Rhodamines; D012503:Saponins; D050998:bcl-2 Homologous Antagonist-Killer Protein; C585486:reevesioside F; C022027:lissamine rhodamine B; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium; D002118:Calcium
keywords: Epi-reevesioside F; bak activation; cytosolic acidification; intracellular Na+ concentration; mitochondrial dysfunction