Regulation of Gene Expression by Sodium Valproate in Epithelial-to-Mesenchymal Transition.
OBJECTIVE
Epithelial-to-mesenchymal transition (EMT) is an important mechanism in cancer metastasis and pulmonary fibrosis. Previous studies demonstrated effect of histone H3 and H4 acetylation in cancer and pulmonary fibrosis, so we hypothesized that histone modification might play a crucial role in gene regulation during EMT. In this study, we investigated the mechanism behind EMT by analyzing comprehensive gene expression and the effect of sodium valproate (VPA), a class I histone deacetylase inhibitory drug, on histone modification.


METHODS
EMT was induced in human alveolar epithelial cells (A549) using 5 ng/mL of transforming growth factor (TGF)-β1. Various concentrations of VPA were then administered, and Western blotting was used to analyze histone acetylation or methylation. Comprehensive gene expression analysis was carried out by RNA sequencing, and chromatin immunoprecipitation was performed with an anti-acetyl histone H3 lysine 27 antibody.


RESULTS
TGF-β1 stimulation led to a decrease in histone acetylation, especially that of histone H3K27, and H3K27ac localization was decreased at particular gene loci. This decrease was recovered by VPA treatment, which also up-regulated the mRNA expression of genes down-regulated by TGF-β1, and correlated with the localization of H3K27ac. However, genes up-regulated by TGF-β1 stimulation were not suppressed by VPA, with the exception of COL1A1.


CONCLUSIONS
Histone acetylation was down-regulated by TGF-β1 stimulation in A549 cells. VPA partially inhibited EMT and the decrease of histone acetylation, which plays an important role in the progression of EMT.
Department of Environmental Medicine, Kochi Medical School, Kochi University, Oko-cho Kohasu, Nankoku, Kochi, 783-8505, Japan.
Shuhei
S
Noguchi
Department of Environmental Medicine, Kochi Medical School, Kochi University, Oko-cho Kohasu, Nankoku, Kochi, 783-8505, Japan.
Masamitsu
M
Eitoku
Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
Shigeharu
S
Moriya
Research Integration Center, Research Organization of Information and Systems, National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo, 190-8518, Japan.
Shinji
S
Kondo
Department of Environmental Medicine, Kochi Medical School, Kochi University, Oko-cho Kohasu, Nankoku, Kochi, 783-8505, Japan.
Hidenori
H
Kiyosawa
Organization for Regional Alliances, Kochi University of Technology, Tosayamada, Kami, Kochi, 782-8502, Japan.|Graduate School of Pharmaceutical Sciences, School of Pharmacy, Kumamoto University, 5-1 Oe, Chuo-ku, Kumamoto, 862-0973, Japan.
Takashi
T
Watanabe
Department of Environmental Medicine, Kochi Medical School, Kochi University, Oko-cho Kohasu, Nankoku, Kochi, 783-8505, Japan. nsuganuma@kochi-u.ac.jp.
Narufumi
N
Suganuma
D000107:Acetylation; D015703:Antigens, CD; D015820:Cadherins / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D024042:Collagen Type I / Q000235:genetics; D000090602:Collagen Type I, alpha 1 Chain; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects*; D042421:Histone Code / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006657:Histones / Q000378:metabolism; D006801:Humans; D051797:Inhibitor of Differentiation Protein 2 / Q000235:genetics; D008175:Lung Neoplasms / Q000235:genetics*; D009088:Mucoproteins; D020411:Oligonucleotide Array Sequence Analysis; D015513:Oncogene Proteins; D010766:Phosphorylation / Q000187:drug effects; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics; D011506:Proteins / Q000235:genetics; D012313:RNA / Q000032:analysis; D051899:Smad2 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D014635:Valproic Acid / Q000494:pharmacology*
C502296:AGR2 protein, human; D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D056572:Histone Deacetylase Inhibitors; D006657:Histones; C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; D009088:Mucoproteins; D015513:Oncogene Proteins; D017395:Plasminogen Activator Inhibitor 1; D011506:Proteins; C051321:SERPINE1 protein, human; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D053773:Transforming Growth Factor beta1; D014635:Valproic Acid; D012313:RNA
Epithelial-to-mesenchymal transition; Histone modification; Non-small cell lung cancer; Pulmonary fibrosis; RNA-Seq; Sodium valproate