title: Down-regulation of Claudin-2 Expression and Proliferation by Epigenetic Inhibitors in Human Lung Adenocarcinoma A549 Cells.
abstract: Claudin-2 is highly expressed in lung adenocarcinoma tissues and increases proliferation in adenocarcinoma cells. The chemicals that reduce claudin-2 expression may have anti-cancer effects, but such therapeutic medicines have not been developed. We found that azacitidine (AZA), a DNA methylation inhibitor, and trichostatin A (TSA) and sodium butyrate (NaB), histone deacetylase (HDAC) inhibitors, decrease claudin-2 levels. The effect of AZA was mediated by the inhibition of phosphorylated Akt and NF-κB. LY-294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K), and BAY 11-7082, an NF-κB inhibitor, decreased claudin-2 levels. The reporter activity of claudin-2 was decreased by AZA and LY-294002, which was blocked by the mutation in a putative NF-κB-binding site. NF-κB bound to the promoter region of claudin-2, which was inhibited by AZA and LY-294002. AZA is suggested to decrease the claudin-2 mRNA level mediated by the inhibition of a PI3K/Akt/NF-κB pathway. TSA and NaB did not change phosphorylated Akt and NF-κB levels. Furthermore, these inhibitors did not change the reporter activity of claudin-2 but decreased the stability of claudin-2 mRNA mediated by the elevation of miR-497 microRNA. The binding of histone H3 to the promoter region of miR-497 was inhibited by TSA and NaB, whereas that of claudin-2 was not. These results suggest that HDAC inhibitors decrease claudin-2 levels mediated by the elevation of miR-497 expression. Cell proliferation was additively decreased by AZA, TSA, and NaB, which was partially rescued by ectopic expression of claudin-2. We suggest that epigenetic inhibitors suppress the abnormal proliferation of lung adenocarcinoma cells highly expressing claudin-2.
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Hichino
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Taga
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Risa
authors.initials: R
authors.lastname: Akizuki
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Endo
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: From the Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196, Japan ikari@gifu-pu.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Ikari
mesh_terms: D000072283:A549 Cells; D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D001374:Azacitidine / Q000494:pharmacology; D020148:Butyric Acid / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects*; D002867:Chromones / Q000494:pharmacology; D062446:Claudin-2 / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D044127:Epigenesis, Genetic / Q000187:drug effects*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D035683:MicroRNAs / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D013450:Sulfones / Q000494:pharmacology
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D002867:Chromones; D062446:Claudin-2; D006877:Hydroxamic Acids; C559640:MIRN497 microRNA, human; D035683:MicroRNAs; D009025:Morpholines; D009570:Nitriles; D012333:RNA, Messenger; D013450:Sulfones; D020148:Butyric Acid; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C012589:trichostatin A; D001374:Azacitidine
keywords: NF-κB; epigenetics; lung cancer; proliferation; tight junction