Abstract
Oridonin has been shown to exhibit therapeutic effects against hepatocellular carcinoma (HCC) in vitro and in vivo. This study aimed to identify the anti-HCC mechanisms of oridonin in HepG2 cells using proteomic and functional analyses. MTT assay showed that oridonin treatment for 24 hours dose-dependently inhibited cell growth with an IC(50) value of 40.4 μM. Treatment with 40 μM oridonin for 24 hours induced apoptosis determined by nuclear morphologic changes of DAPI-stained cells and flow cytometric analysis of annexin V-FITC/PI-stained cells, which was accompanied by Grp78 upregulation and α-CP1 downregulation identified by proteomic analysis. Immunoblot analysis for the endoplasmic reticulum (ER) stress- related proteins demonstrated that the expression levels of phosphorylated PERK (p-PERK) and CHOP were increased, whereas PERK, ATF-6, and IRE-1 expression levels were decreased. Knockdown of α-CP1 expression with siRNA significantly increased cell death and apoptosis in control and oridonin-treated HepG2 cells. Together, these data provide proteomic and functional evidence for the potential involvement of ER stress and α-CP1 in the antiproliferative and apoptotic activities of oridonin in HepG2 cells, which shed new light on the action mechanisms of oridonin in HCC management.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Activating Transcription Factor 6 / metabolism
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Antineoplastic Agents, Phytogenic / pharmacology*
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Apoptosis / drug effects
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Apoptosis / genetics
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Carcinoma, Hepatocellular / drug therapy
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Cell Proliferation / drug effects
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Cell Survival / drug effects
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Cell Survival / genetics
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DNA-Binding Proteins
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Diterpenes, Kaurane / pharmacology*
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Endoplasmic Reticulum Chaperone BiP
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Endoplasmic Reticulum Stress / drug effects*
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Endoribonucleases / metabolism
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Gene Expression / drug effects
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Gene Expression / genetics
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Heat-Shock Proteins / metabolism
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Hep G2 Cells
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Heterogeneous-Nuclear Ribonucleoproteins / genetics
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Heterogeneous-Nuclear Ribonucleoproteins / metabolism*
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Humans
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Liver Neoplasms / drug therapy
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Membrane Proteins / metabolism
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Phosphorylation / drug effects
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Protein Serine-Threonine Kinases / metabolism
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Proteomics*
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RNA, Small Interfering / genetics
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RNA-Binding Proteins
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Transcription Factor CHOP / metabolism
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eIF-2 Kinase / metabolism
Substances
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ATF6 protein, human
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Activating Transcription Factor 6
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Antineoplastic Agents, Phytogenic
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DDIT3 protein, human
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DNA-Binding Proteins
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Diterpenes, Kaurane
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Endoplasmic Reticulum Chaperone BiP
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HSPA5 protein, human
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Heat-Shock Proteins
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Heterogeneous-Nuclear Ribonucleoproteins
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Membrane Proteins
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PCBP1 protein, human
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RNA, Small Interfering
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RNA-Binding Proteins
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oridonin
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Transcription Factor CHOP
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ERN2 protein, human
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PERK kinase
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Protein Serine-Threonine Kinases
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eIF-2 Kinase
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Endoribonucleases