Epigenetic control of HNF-4α in colon carcinoma cells affects MUC4 expression and malignancy.

Abstract

BACKGROUND:

We previously found that enhanced expression of hepatocyte nuclear factor 4α (HNF-4α) is associated with hyper-proliferation of colon carcinoma cells. Here, the effect of histone deacetylase (HDAC) inhibitors on proliferation and the expression of HNF-4α and its downstream target genes were assessed in HM7, LS174T, HT29 and Caco-2 colon carcinoma cell lines.

RESULTS:

HNF-4α expression was found to vary in the different colon carcinoma cell lines tested, being highest in HM7. Additionally, a direct correlation with proliferation was observed. In HM7 cells, the weak HDAC inhibitor butyrate significantly inhibited the transcription of HNF-4α, its downstream target gene MUC4, and genes associated with proliferation, including the proliferating cell nuclear antigen gene PCNA. siRNA-mediated silencing of HNF-4α exerted an effect similar to butyrate on HM7 cell proliferation. The stronger HDAC inhibitor trichostatin A (TSA) exerted an effect similar to that of siRNA-mediated HNF-4α silencing and, concomitantly, inhibited the expression of the transcription factor gene SP1. Also, siRNA-mediated silencing of HDAC3 and HDAC4 reduced HNF-4α expression. Chromatin immunoprecipitation (ChIP) assays revealed that TSA induces hyperacetylation of histones H3 and H4 and, concomitantly, inhibits SP1 binding to the HNF-4α promoter. Subsequent electromobility shift assays supported these latter findings.

CONCLUSIONS:

HNF-4α transcriptional expression and activity are tightly controlled by epigenetic mechanisms. HDAC inhibitor targeting of HNF-4α may serve as an effective treatment for advanced colon carcinomas, since downstream cancer-associated target genes such as MUC4 are significantly down-regulated by this treatment.

• Authors: Anna Algamas-Dimantov, Einav Yehuda-Shnaidman, Irena Peri, Betty Schwartz
• Journal: Cellular oncology (Dordrecht) (Cell Oncol (Dordr)) Vol. 36 Issue 2 Pg. 155-67 (Apr 2013) ISSN: 2211-3436 [Electronic] Netherlands
• PMID: 23307400 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Butyrates
• HNF4A protein, human
• Hepatocyte Nuclear Factor 4
• Histone Deacetylase Inhibitors
• Histones
• Hydroxamic Acids
• MUC4 protein, human
• Mucin-4
• Repressor Proteins
• Sp1 Transcription Factor
• trichostatin A
• HDAC4 protein, human
• Histone Deacetylases
• histone deacetylase 3

Topics

• Acetylation (drug effects)
• Blotting, Western
• Butyrates (pharmacology)
• Caco-2 Cells
• Cell Line, Tumor
• Cell Proliferation
• Colonic Neoplasms (genetics, metabolism, pathology)
• Epigenesis, Genetic
• Gene Expression Regulation, Neoplastic
• HT29 Cells
• Hepatocyte Nuclear Factor 4 (genetics, metabolism)
• Histone Deacetylase Inhibitors (pharmacology)
• Histone Deacetylases (genetics, metabolism)
• Histones (metabolism)
• Humans
• Hydroxamic Acids (pharmacology)
• Mucin-4 (genetics, metabolism)
• Promoter Regions, Genetic (genetics)
• Protein Binding (drug effects)
• RNA Interference
• Repressor Proteins (genetics, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Sp1 Transcription Factor (genetics, metabolism)
• Transcription, Genetic (drug effects)