title: Clathrin-dependent endocytosis of claudin-2 by DFYSP peptide causes lysosomal damage in lung adenocarcinoma A549 cells.
abstract: Claudins are tight junctional proteins and comprise a family of over 20 members. Abnormal expression of claudins is reported to be involved in tumor progression. Claudin-2 is highly expressed in lung adenocarcinoma tissues and increases cell proliferation, whereas it is not expressed in normal tissues. Claudin-2-targeting molecules such as peptides and small molecules may be novel anti-cancer drugs. The short peptide with the sequence DFYSP, which mimics the second extracellular loop of claudin-2, decreased claudin-2 content in the cytoplasmic fraction of A549 cells. In contrast, it did not affect the content in the nuclear fraction. The decrease in claudin-2 content was inhibited by chloroquine (CQ), a lysosomal inhibitor, but not by MG-132, a proteasome inhibitor. In the presence of DFYSP peptide and CQ, claudin-2 was co-localized with LAMP-1, a lysosomal marker. The DFYSP peptide-induced decrease in claudin-2 content was inhibited by monodancylcadaverine (MDC), an inhibitor of clathrin-dependent endocytosis. DFYSP peptide increased lysosome content and cathepsin B release, and induced cellular injury, which were inhibited by MDC. Cellular injury induced by DFYSP peptide was inhibited by necrostatin-1, an inhibitor of necrotic cell death, but not by Z-VAD-FMK, an inhibitor of apoptotic cell death. Our data indicate that DFYSP peptide increases the accumulation of the peptide and claudin-2 into the lysosome, resulting in lysosomal damage. Claudin-2 may be a new target for lung cancer therapy.
authors.affiliation: The Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Japan. Electronic address: ikari@gifu-pu.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Ikari
authors.affiliation: The Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Taga
authors.affiliation: Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan.
authors.forename: Tomonari
authors.initials: T
authors.lastname: Sato
authors.affiliation: The Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Shimobaba
authors.affiliation: The Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sonoki
authors.affiliation: The Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Endo
authors.affiliation: The Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Sakai
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Yamaguchi
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamazaki
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Sugatani
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002966:Clathrin / Q000378:metabolism*; D062446:Claudin-2 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004705:Endocytosis / Q000187:drug effects; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology*; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D010455:Peptides / Q000008:administration & dosage*
chemical_list: D002966:Clathrin; D062446:Claudin-2; D010455:Peptides
keywords: Adenocarcinoma; Claudin-2; Lung; Lysosomal damage