Interaction with cyclin H/cyclin-dependent kinase 7 (CCNH/CDK7) stabilizes C-terminal binding protein 2 (CtBP2) and promotes cancer cell migration.

Abstract

CtBP2 has been demonstrated to possess tumor-promoting capacities by virtue of up-regulating epithelial-mesenchymal transition (EMT) and down-regulating apoptosis in cancer cells. As a result, cellular CtBP2 levels are considered a key factor determining the outcome of oncogenic transformation. How pro-tumorigenic and anti-tumorigenic factors compete for fine-tuning CtBP2 levels is incompletely understood. Here we report that the cyclin H/cyclin-dependent kinase 7 (CCNH/CDK7) complex interacted with CtBP2 in vivo and in vitro. Depletion of either CCNH or CDK7 decreased CtBP2 protein levels by accelerating proteasome-dependent CtBP2 clearance. Further analysis revealed that CCNH/CDK7 competed with the tumor repressor HIPK2 for CtBP2 binding and consequently inhibited phosphorylation and dimerization of CtBP2. Phosphorylation-defective CtBP2 interacted more strongly with CCNH/CDK7 and was more resistant to degradation. Finally, overexpression of CtBP2 increased whereas depletion of CtBP2 dampened the invasive and migratory potential of breast cancer cells. CtBP2 promoted the invasion and migration of breast cancer cells in a CCNH-dependent manner. Taken together, our data have delineated a novel pathway that regulates CtBP2 stability, suggesting that targeting the CCNH/CDK7-CtBP2 axis may yield a viable anti-tumor strategy.

• Authors: Yuchan Wang, Fang Liu, Feng Mao, Qinlei Hang, Xiaodong Huang, Song He, Yingying Wang, Chun Cheng, Huijie Wang, Guangfei Xu, Tianyi Zhang, Aiguo Shen
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 288 Issue 13 Pg. 9028-34 (Mar 29 2013) ISSN: 1083-351X [Electronic] United States
• PMID: 23393140 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Co-Repressor Proteins
• Nerve Tissue Proteins
• Protein Synthesis Inhibitors
• Cycloheximide
• Alcohol Oxidoreductases
• CTBP2 protein, human
• Cyclin-Dependent Kinases
• Proteasome Endopeptidase Complex
• Cyclin-Dependent Kinase-Activating Kinase
• CDK7 protein, human

Topics

• Alcohol Oxidoreductases (metabolism)
• Cell Line, Tumor
• Cell Movement
• Co-Repressor Proteins
• Cyclin-Dependent Kinases (metabolism)
• Cycloheximide (pharmacology)
• Gene Expression Regulation, Neoplastic
• HEK293 Cells
• Humans
• Neoplasm Metastasis
• Neoplasms (metabolism)
• Nerve Tissue Proteins (metabolism)
• Proteasome Endopeptidase Complex (metabolism)
• Protein Binding
• Protein Interaction Mapping
• Protein Structure, Tertiary
• Protein Synthesis Inhibitors (pharmacology)
• Transfection
• Cyclin-Dependent Kinase-Activating Kinase