MZF-1/Elk-1 Complex Binds to Protein Kinase Cα Promoter and Is Involved in Hepatocellular Carcinoma

PLoS One. 2015 May 26;10(5):e0127420. doi: 10.1371/journal.pone.0127420. eCollection 2015.

Abstract

In this study, the molecular mechanism of protein kinase C alpha (PKCα) gene regulation in hepatocellular carcinoma (HCC) involving Ets-like protein-1 (Elk-1) and myeloid zinc finger-1 (MZF-1) was investigated. The luciferase reporter assay results revealed that the presence of both MZF-1 and Elk-1 significantly contributed to the upregulation of PKCα gene transcription activity, and the transcriptional activity decreased when the transfection included a DNA-binding-deficient (∆DBD) gene vector of either MZF-1 or Elk-1 DNA-binding deficiency (MZF-1∆DBD or Elk-1∆DBD), thereby indicating that the enhanced expression of PKCα was caused by the binding of MZF-1 and/or Elk-1 with the PKCα promoter. We investigated MZF-1 and Elk-1 to determine whether they bind to each other. The results of immunoprecipitation (IP), Co-IP, chromatin IP (ChIP), and Re-ChIP analyses indicated that Elk-1 can directly bind to the N-terminal region of MZF-1 and MZF-1 can directly bind to the C-terminal region of Elk-1 to form a complex before attaching to the PKCα promoter. Furthermore, when MZF-1∆DBD or Elk-1∆DBD was added to the cells, PKCα expression decreased, and cell proliferation, migration, invasion, and tumorigenicity also decreased. These findings suggest that PKCα expression in HCC could be stimulated by the formation of MZF-1/Elk-1 complex, which directly binds to the PKCα promoter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / metabolism*
  • Carcinoma, Hepatocellular / pathology
  • Gene Expression Regulation, Enzymologic*
  • Gene Expression Regulation, Neoplastic*
  • Hep G2 Cells
  • Humans
  • Kruppel-Like Transcription Factors / genetics
  • Kruppel-Like Transcription Factors / metabolism*
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism*
  • Liver Neoplasms / pathology
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism
  • Protein Kinase C-alpha / biosynthesis*
  • Protein Kinase C-alpha / genetics
  • Protein Structure, Tertiary
  • Response Elements*
  • Transcription, Genetic
  • Up-Regulation
  • ets-Domain Protein Elk-1 / genetics
  • ets-Domain Protein Elk-1 / metabolism*

Substances

  • ELK1 protein, human
  • Kruppel-Like Transcription Factors
  • MZF1 protein, human
  • Multiprotein Complexes
  • ets-Domain Protein Elk-1
  • PRKCA protein, human
  • Protein Kinase C-alpha

Grants and funding

This work was supported by grants from the Ministry of Science and Technology, Republic of China (NSC 99-2632-B-039-001-MY3, NSC 102-2320-B-039-049 and NSC102-2911-I-002-303) and by the Taiwan Department of Health Clinical Trial and Research Center of Excellence (DOH102-TD-B-111-004), Taiwan, Republic of China.