title: 17β-Estradiol Inhibites Tumor Necrosis Factor-α Induced Apoptosis of Human Nucleus Pulposus Cells via the PI3K/Akt Pathway.
abstract: BACKGROUND Tumor necrosis factor-α (TNF-α) has been widely known to induce degeneration of nucleus pulposus cells (NPCs). 17β-estradiol (17β-E2) has been broadly proven for its function of suppressing cell apoptosis. The aim of this study is to explore whether 17β-E2 protects apoptosis of human NPCs induced by TNF-α via the PI3K/AKT pathway. MATERIAL AND METHODS NPCs were divided into four groups: control, TNF-α (100 ng/mL), TNF-α (100 ng/mL) with pretreated 17β-E2 (10 um/L), TNF-α (100 ng/mL) with pretreated 17β-E2 (10 um/L) and MK2206 (10 um/L, inhibitor of the PI3K/AKT pathway). Flow cytometry was used to measure the apoptotic incidence. Inverted phase-contrast microscopy was used to accomplish the morphological observation for apoptosis of treated cells. Additionally, Cell Counting Kit 8 (CCK-8) assay was used to detected cell proliferation. Western blot and quantitative real-time PCR (qRT-PCR) were applied to explore the expression of pro-caspase-3, caspase-3/p17, cleaved PARP, PARP, Akt, and phospho-Akt (p-Akt). RESULTS First, inverted phase-contrast microscopy, CCK-8, and flow cytometry showed that TNF-α induced marked apoptosis, which was abolished by 17β-E2. Furthermore, Western blot and qRT-PCR showed that 17β-E2 protects TNF-α which can induced apoptosis by upregulating p-Akt, whereas Akt was essentially constant. Our data revealed that p-Akt expression peaked at 24 hours in a time-dependent manner (0-48 hours) after treating with TNF-α; and the p-Akt expression generally increased in a time-dependent manner (0-48 hours) after treating with TNF-α and 17β-E2. CONCLUSIONS 17β-E2 is shown to protect NPCs against TNF-α induced apoptosis by upregulating p-Akt in the PI3K/AKT pathway. 17β-E2 generally increases expression of p-Akt.
authors.affiliation: Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China (mainland).
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China (mainland).
authors.forename: Si-Dong
authors.initials: SD
authors.lastname: Yang
authors.affiliation: Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China (mainland).
authors.forename: Sen
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China (mainland).
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China (mainland).
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, China (mainland).
authors.forename: Wen Yuan
authors.initials: WY
authors.lastname: Ding
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D006801:Humans; D000070614:Nucleus Pulposus / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D020011:Protective Agents / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D020011:Protective Agents; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D004958:Estradiol; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt
keywords: Accessory nerve; Estriol; Tumor Necrosis Factors