Claudin-4 Overexpression in Epithelial Ovarian Cancer Is Associated with Hypomethylation and Is a Potential Target for Modulation of Tight Junction Barrier Function Using a C-Terminal Fragment of Clostridium perfringens Enterotoxin

• Published in: Neoplasia (New York, N.Y.) Vol. 9; no. 4; pp. 304 - 314
• Main Authors: Litkouhi, Babak, Kwong, Joseph, Lot, Chun-Min, Smedley, James G., McClane, Bruce A., Aponte, Margarita, Gao, Zhijian, Sarno, Jennifer L., Hinners, Jennifer, Welch, William R., Berkowitz, Ross S., Mok, Samuel C., Garner, Elizabeth I.O.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2007; Elsevier
• Subjects: Cell Line, Tumor; Claudin-4; Clostridium perfringens - physiology; DNA Methylation - drug effects; Dose-Response Relationship, Drug; Drug Delivery Systems - methods; Enterotoxins - administration & dosage; Enterotoxins - toxicity; Female; gene expression; Humans; Membrane Proteins - biosynthesis; Membrane Proteins - genetics; methylation; Neoplasms, Glandular and Epithelial - drug therapy; Neoplasms, Glandular and Epithelial - genetics; Neoplasms, Glandular and Epithelial - metabolism; Ovarian cancer; Ovarian Neoplasms - drug therapy; Ovarian Neoplasms - genetics; Ovarian Neoplasms - metabolism; Peptide Fragments - administration & dosage; Peptide Fragments - toxicity; therapy; Tight Junctions - drug effects; Tight Junctions - enzymology; Tight Junctions - physiology; Rb; therapy; methylation; IP; claudin-4; ECIS; EOC; HOSE; CPE; C-CPE; gene expression; Ovarian cancer
• ISSN: 1476-5586; 1476-5586
• DOI: 10.1593/neo.07118

BACKGROUND: Claudin-4, a tight junction (TJ) protein and receptor for the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), is overexpressed in epithelial ovarian cancer (EOC). Previous research suggests DNA methylation is a mechanism for claudin-4 overexpression in cancer and that C-CPE acts as an absorption-enhancing agent in claudin-4expressing cells. We sought to correlate claudin-4 overexpression in EOC with clinical outcomes and TJ barrier function, investigate DNA methylation as a mechanism for overexpression, and evaluate the effect of C-CPE on the TJ. METHODS: Claudin-4 expression in EOC was quantified and correlated with clinical outcomes. Claudin-4 methylation status was determined, and claudin-4-negative cell lines were treated with a demethylating agent. Electric cell-substrate impedance sensing was used to calculate junctional (paracellular) resistance (Rb) in EOC cells after claudin-4 silencing and after C-CPE treatment. RESULTS: Claudin4 overexpression in EOC does not correlate with survival or other clinical endpoints and is associated with hypomethylation. Claudin-4 overexpression correlates with Rb and C-CPE treatment of EOC cells significantly decreased Rb in a dose- and claudin-4-dependent noncytotoxic manner. CONCLUSIONS: C-CPE treatment of EOC cells leads to altered TJ function. Further research is needed to determine the potential clinical applications of C-CPE in EOC drug delivery strategies.