Abstract |
Using short hairpin RNA against p53, transient ectopic expression of wild-type p53 or mutant p53 (R248W or R175H), and a p53- and p21-dependent luciferase reporter assay, we demonstrated that growth arrest and apoptosis of FaDu (human pharyngeal squamous cell carcinoma), Hep3B ( hepatoma), and MG-63 ( osteosarcoma) cells induced by aloe-emodin (AE) are p53-independent. Co-immunoprecipitation and small interfering RNA ( siRNA) studies demonstrated that AE caused S-phase cell cycle arrest by inducing the formation of cyclin A-Cdk2-p21 complexes through extracellular signal-regulated kinase (ERK) activation. Ectopic expression of Bcl-X(L) and siRNA-mediated Bax attenuation significantly inhibited apoptosis induced by AE. Cyclosporin A or the caspase-8 inhibitor Z-IETD-FMK blocked AE-induced loss of mitochondrial membrane potential and prevented increases in reactive oxygen species and Ca(++). Z-IETD-FMK inhibited AE-induced apoptosis, Bax expression, Bid cleavage, translocation of tBid to mitochondria, ERK phosphorylation, caspase-9 activation, and the release of cytochrome c, apoptosis-inducing factor (AIF), and endonuclease G from mitochondria. The stability of the mRNAs encoding caspase-8 and -10-associated RING proteins (CARPs) 1 and 2 was affected by AE, whereas CARP1 or 2 overexpression inhibited caspase-8 activation and apoptosis induced by AE. Collectively, our data indicate AE induces caspase-8-mediated activation of mitochondrial death pathways by decreasing the stability of CARP mRNAs in a p53-independent manner.
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Authors | Meng-Liang Lin, Yao-Cheng Lu, Hong-Lin Su, Hsin-Ting Lin, Chuan-Chun Lee, Shang-En Kang, Tan-Chen Lai, Jing-Gung Chung, Shih-Shun Chen |
Journal | Journal of cellular biochemistry
(J Cell Biochem)
Vol. 112
Issue 4
Pg. 1176-91
(Apr 2011)
ISSN: 1097-4644 [Electronic] United States |
PMID | 21308745
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2011 Wiley-Liss, Inc. |
Chemical References |
- Apoptosis Regulatory Proteins
- CA11 protein, human
- CCAR1 protein, human
- CDKN1A protein, human
- Carrier Proteins
- Cell Cycle Proteins
- Cyclin A
- Cyclin-Dependent Kinase Inhibitor p21
- Nerve Tissue Proteins
- Protein Kinase Inhibitors
- RNA, Messenger
- Tumor Suppressor Protein p53
- Cyclin-Dependent Kinase 2
- Extracellular Signal-Regulated MAP Kinases
- Caspase 8
- Emodin
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Topics |
- Animals
- Apoptosis
(drug effects)
- Apoptosis Regulatory Proteins
- Blotting, Western
- Carrier Proteins
(genetics, metabolism)
- Caspase 8
(genetics, metabolism)
- Cell Cycle
(drug effects)
- Cell Cycle Proteins
- Cell Line
- Cell Line, Tumor
- Cyclin A
(genetics, metabolism)
- Cyclin-Dependent Kinase 2
(genetics, metabolism)
- Cyclin-Dependent Kinase Inhibitor p21
(genetics, metabolism)
- Emodin
(pharmacology)
- Extracellular Signal-Regulated MAP Kinases
(metabolism)
- HEK293 Cells
- Humans
- Neoplasms
(genetics, metabolism, pathology)
- Nerve Tissue Proteins
(genetics, metabolism)
- Phosphorylation
(drug effects)
- Protein Binding
(drug effects)
- Protein Kinase Inhibitors
(pharmacology)
- RNA Interference
- RNA Stability
(drug effects)
- RNA, Messenger
(genetics, metabolism)
- Reverse Transcriptase Polymerase Chain Reaction
- Tumor Suppressor Protein p53
(genetics, metabolism)
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