Proteomic and functional analyses reveal the potential involvement of endoplasmic reticulum stress and α-CP1 in the anticancer activities of oridonin in HepG2 cells.

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.

• Authors: Hui Wang, Yan Ye, Jian-Hong Chu, Guo-Yuan Zhu, Wang-Fun Fong, Zhi-Ling Yu
• Journal: Integrative cancer therapies (Integr Cancer Ther) Vol. 10 Issue 2 Pg. 160-7 (Jun 2011) ISSN: 1552-695X [Electronic] United States
• PMID: 20926737 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• ATF6 protein, human
• Activating Transcription Factor 6
• Antineoplastic Agents, Phytogenic
• DDIT3 protein, human
• DNA-Binding Proteins
• Diterpenes, Kaurane
• Endoplasmic Reticulum Chaperone BiP
• HSPA5 protein, human
• Heat-Shock Proteins
• Heterogeneous-Nuclear Ribonucleoproteins
• Membrane Proteins
• PCBP1 protein, human
• RNA, Small Interfering
• RNA-Binding Proteins
• oridonin
• Transcription Factor CHOP
• ERN2 protein, human
• PERK kinase
• Protein Serine-Threonine Kinases
• eIF-2 Kinase
• Endoribonucleases

Topics

• Activating Transcription Factor 6 (metabolism)
• Antineoplastic Agents, Phytogenic (pharmacology)
• Apoptosis (drug effects, genetics)
• Carcinoma, Hepatocellular (drug therapy)
• Cell Proliferation (drug effects)
• Cell Survival (drug effects, genetics)
• DNA-Binding Proteins
• Diterpenes, Kaurane (pharmacology)
• Endoplasmic Reticulum Chaperone BiP
• Endoplasmic Reticulum Stress (drug effects)
• Endoribonucleases (metabolism)
• Gene Expression (drug effects, genetics)
• Heat-Shock Proteins (metabolism)
• Hep G2 Cells
• Heterogeneous-Nuclear Ribonucleoproteins (genetics, metabolism)
• Humans
• Liver Neoplasms (drug therapy)
• Membrane Proteins (metabolism)
• Phosphorylation (drug effects)
• Protein Serine-Threonine Kinases (metabolism)
• Proteomics
• RNA, Small Interfering (genetics)
• RNA-Binding Proteins
• Transcription Factor CHOP (metabolism)
• eIF-2 Kinase (metabolism)