IKKβ downregulation is critical for triggering JNKs-dependent cell apoptotic response in the human hepatoma cells under arsenite exposure.

Abstract

Arsenite has a long history in treating leukemia, which might be also effective in the therapy of other cancers. Our previous published data have demonstrated that arsenite exposure induces apoptosis in the HepG2 human hepatoma cells via activating JNKs/AP-1 pathway, but the upstream signaling events responsible for JNKs (c-Jun N-terminal kinase) cascade activation have not been fully discovered. Since cross-talk between IKK/NF-κB and JNKs pathways under stress conditions is a hot topic, in this article, we investigate the potential roles of IKKα and IKKβ, the catalytic subunits of IKK complexes, in the arsenite-induced JNKs pathway activation in the HepG2 cells. We found that arsenite exposure induced JNKs and AP-1 activation accompanying with a significant reduction of both IKKα and IKKβ expressions. Overexpression of IKKβ, but not of IKKα, inhibited arsenite-induced MKK7/JNKs/AP-1 pathway activation as well as the apoptotic response. Therefore, we conclude that the downregulation of IKKβ expression is the prerequisite signaling event for mediating JNKs pathway activation and the cellular apoptotic response in the HepG2 cells under arsenite exposure. Targeting IKKβ might be helpful to enhance the tumor therapeutic effect of arsenite.

• Authors: Yi Li, Yi Hao, Ming Gao, Wen Dong, Meiru Hu, Shengtao Yuan, Lun Song
• Journal: Molecular and cellular biochemistry (Mol Cell Biochem) Vol. 358 Issue 1-2 Pg. 61-6 (Dec 2011) ISSN: 1573-4919 [Electronic] Netherlands
• PMID: 21688155 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Arsenites
• Transcription Factor AP-1
• I-kappa B Kinase
• JNK Mitogen-Activated Protein Kinases
• arsenite

Topics

• Apoptosis (drug effects)
• Arsenites (pharmacology)
• Carcinoma, Hepatocellular (enzymology, pathology)
• Down-Regulation (drug effects)
• Enzyme Activation (drug effects)
• Hep G2 Cells
• Humans
• I-kappa B Kinase (metabolism)
• JNK Mitogen-Activated Protein Kinases (metabolism)
• Liver Neoplasms (enzymology, pathology)
• Transcription Factor AP-1 (genetics)
• Transcriptional Activation (drug effects)