title: Tight junction proteins claudin-3 and claudin-4 control tumor growth and metastases.
abstract: The extent of tight junction (TJ) formation is one of many factors that regulate motility, invasion, and metastasis. Claudins are required for the formation and maintenance of TJs. Claudin-3 (CLDN3) and claudin-4 (CLDN4) are highly expressed in the majority of ovarian cancers. We report here that CLDN3 and CLDN4 each serve to constrain the growth of human 2008 cancer xenografts and limit metastatic potential. Knockdown of CLDN3 increased in vivo growth rate by 2.3-fold and knockdown of CLDN4 by 3.7-fold in the absence of significant change in in vitro growth rate. Both types of tumors exhibited increase in birth rate as measured by Ki67 staining and decrease in death rate as reflected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Knockdown of either claudin did not alter expression of other TJ protein but did reduce TJ formation as measured by transepithelial resistance and paracellular flux of dextran, enhance migration and invasion in in vitro assays, and increase lung colonization following intravenous injection. Knockdown of CLDN3 and CLDN4 increased total lung metastatic burden by 1.7-fold and 2.4-fold, respectively. Loss of either CLDN3 or CLDN4 resulted in down-regulation of E-cadherin mRNA and protein, increased inhibitory phosphorylation of glycogen synthase kinase-3β (GSK-3β), and activation of β-catenin pathway signaling as evidenced by increases in nuclear β-catenin, the dephosphorylated form of the protein, and transcriptional activity of β-catenin/T-cell factor (TCF). We conclude that both CLDN3 and CLDN4 mediate interactions with other cells in vivo that restrain growth and metastatic potential by sustaining expression of E-cadherin and limiting β-catenin signaling.
authors.affiliation: Department of Medicine and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Xiying
authors.initials: X
authors.lastname: Shang
authors.forename: Xinjian
authors.initials: X
authors.lastname: Lin
authors.forename: Edwin
authors.initials: E
authors.lastname: Alvarez
authors.forename: Gerald
authors.initials: G
authors.lastname: Manorek
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Howell
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D062465:Claudin-3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D062506:Claudin-4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017097:Electric Impedance; D005185:Fallopian Tube Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000556:secondary*; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D019108:Tight Junctions; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D014945:Wound Healing; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: C568122:CLDN3 protein, human; C568157:CLDN4 protein, human; D015820:Cadherins; D062465:Claudin-3; D062506:Claudin-4; D012333:RNA, Messenger; D051176:beta Catenin; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3