title: Knockdown of Apolipoprotein E Enhanced Sensitivity of Hep3B Cells to Cardiac Steroids via Regulating Na+/K+-ATPase Signalosome.
abstract: This study compared the sensitivity of human hepatoma Hep3B, SK-HEP-1, SMMC-7721, and BEL-7402 cells to cardiac steroids, including bufalin (BF), a bufalin derivative (BF211), ouabain (OUA), and digitoxin (DIG). Hep3B cells exhibited relatively low sensitivity to cardiac steroids. Expression levels of subunits of Na+/K+-ATPase were high in Hep3B cells. However, colocalization of Na+/K+-ATPase and caveolin was nearly undetectable in Hep3B cells. By using RNA-Seq technology, we found a total of 36 genes to be differentially expressed between Hep3B cells and SK-HEP-1 cells, which are highly sensitive to cardiac steroids. Our bioinformatics analysis determined that these genes were mostly comprised of extracellular space, protein binding, and extracellular region. Among these 36 genes, apolipoprotein E (APOE) played a critical role, as knockdown APOE expression induced colocalization of Na+/K+-ATPase and caveolin and increased sensitivity of Hep3B cells to both proliferation-inhibiting and cytotoxic effects of BF or BF211. Also, the effects of BF on PI3K/AKT/GSK3β and apoptosis signal cascades were enhanced in APOE knockdown cells. The results of our study confirmed the role of Na+/K+-ATPase signalosome in cytotoxicity of cardiac steroids and suggested that APOE regulated the sensitivity of cells to cardiac steroids by affecting formation and function of Na+/K+-ATPase signalosome. In addition, intercellular interaction with high level of Na+/K+-ATPase β1 subunit may be also a factor in the low sensitivity of Hep3B cells to cardiac steroids. Mol Cancer Ther; 15(12); 2955-65. ©2016 AACR.
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Miao
authors: M
authors: Liu
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Li-Xing
authors: LX
authors: Feng
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Peng
authors: P
authors: Sun
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Wang
authors: W
authors: Liu
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Tian
authors: T
authors: Mi
authors: State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Min
authors: M
authors: Lei
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Wanying
authors: W
authors: Wu
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Baohong
authors: B
authors: Jiang
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China.
authors: Min
authors: M
authors: Yang
authors: State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China. lhhu@simm.ac.cn daguo@simm.ac.cn xuanliu@simm.ac.cn.
authors: Lihong
authors: L
authors: Hu
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China. lhhu@simm.ac.cn daguo@simm.ac.cn xuanliu@simm.ac.cn.
authors: De-An
authors: DA
authors: Guo
authors: Shanghai Research Center for Modernization of TCM, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China. lhhu@simm.ac.cn daguo@simm.ac.cn xuanliu@simm.ac.cn.|Department of Cardiology, Shanghai Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, P.R. China.
authors: Xuan
authors: X
authors: Liu
mesh_terms: D001057:Apolipoproteins E / Q000172:deficiency*; D017209:Apoptosis / Q000187:drug effects; D002301:Cardiac Glycosides / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D022461:Caveolins / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015870:Gene Expression; D055786:Gene Knockout Techniques; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs / Q000235:genetics; D021381:Protein Transport; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001057:Apolipoproteins E; D002301:Cardiac Glycosides; D020169:Caspases; D022461:Caveolins; D000071679:Glycogen Synthase Kinase 3 beta; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D000254:Sodium-Potassium-Exchanging ATPase