title: Effects of Clostridium perfringens enterotoxin via claudin-4 on normal human pancreatic duct epithelial cells and cancer cells.
abstract: The tight junction protein claudin-4 is frequently overexpressed in pancreatic cancer, and is also a receptor for Clostridium perfringens enterotoxin (CPE). The cytotoxic effects of CPE are thought to be useful as a novel therapeutic tool for pancreatic cancer. However, the responses to CPE via claudin-4 remain unknown in normal human pancreatic duct epithelial (HPDE) cells. We introduced the human telomerase reverse transcriptase (hTERT) gene into HPDE cells in primary culture as a model of normal HPDE cells in vitro. hTERT-HPDE cells treated with or without 10% FBS and pancreatic cancer cell lines PANC-1, BXPC3, HPAF-II and HPAC were treated with CPE. In Western blotting, the expression of claudin-4 protein in hTERT-HPDE cells treated with 10% FBS was as high as it was in all of the pancreatic cancer cell lines. In hTERT-HPDE cells with or without 10% FBS, cytotoxicity was not observed at any concentration of CPE, whereas in all pancreatic cancer cell lines, CPE had a dose-dependent cytotoxic effect. In hTERT-HPDE cells with 10% FBS, claudin-4 was localized in the apical-most regions, where there are tight junction areas, in which in all pancreatic cancer cell lines claudin-4 was found not only in the apical-most regions but also at basolateral membranes. In hTERT-HPDE cells with 10% FBS after treatment with CPE, downregulation of barrier function and claudin-4 expression at the membranes was observed. In HPAC cells, the sensitivity to CPE was significantly decreased by knockdown of claudin-4 expression using siRNA compared to the control. These findings suggest that, in normal HPDE cells, the lack of toxicity of CPE was probably due to the localization of claudin-4, which is different from that of pancreatic cancer cells. hTERT-HPDE cells in this culture system may be a useful model of normal HPDE cells not only for physiological regulation of claudin-4 expression but also for developing safer and more effective therapeutic methods targeting claudin-4 in pancreatic cancer.
authors.affiliation: Department of Surgery, Sapporo Medical University School of Medicine, Sapporo, 060-8556, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Kojima
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ito
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kyuno
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Kimura
authors.forename: Masafumi
authors.initials: M
authors.lastname: Imamura
authors.forename: Koichi
authors.initials: K
authors.lastname: Hirata
authors.forename: Norimasa
authors.initials: N
authors.lastname: Sawada
mesh_terms: D015153:Blotting, Western; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism / Q000473:pathology*; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D062445:Claudin-1; D062506:Claudin-4; D057167:Claudins / Q000378:metabolism*; D017097:Electric Impedance; D004768:Enterotoxins / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism; D062793:Occludin; D010183:Pancreatic Ducts / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism
chemical_list: C568108:CLDN1 protein, human; C568157:CLDN4 protein, human; C473255:CLDN7 protein, human; D062445:Claudin-1; D062506:Claudin-4; D057167:Claudins; D004768:Enterotoxins; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D034741:RNA, Small Interfering; C035598:enterotoxin, Clostridium; C509186:TERT protein, human; D019098:Telomerase