title: Overexpression of Clostridium perfringens enterotoxin receptors claudin-3 and claudin-4 in uterine carcinosarcomas.
abstract: OBJECTIVE
  To evaluate the expression levels of claudin-3 and claudin-4, the low- and high-affinity receptors, respectively, for the cytotoxic Clostridium perfringens enterotoxin (CPE) in uterine carcinosarcomas and explore the potential for targeting these receptors in the treatment of this aggressive uterine tumor.
  
  
  METHODS
  We analyzed claudin-3 and claudin-4 receptor expression at mRNA and protein levels in flash frozen and formalin-fixed, paraffin-embedded carcinosarcoma specimens. Recombinant CPE was used as a novel therapy against chemotherapy-resistant carcinosarcoma cell lines in vitro. The therapeutic effect of sublethal doses of CPE was studied in severe combined immunodeficient mouse xenografts harboring large s.c. carcinosarcomas.
  
  
  RESULTS
  All flash-frozen carcinosarcoma biopsies (12 of 12) and short-term carcinosarcoma cell lines evaluated overexpressed claudin-3 and claudin-4 by quantitative reverse transcription-PCR. Membranous immunoreactivity for claudin-4 protein expression was documented in 80% (20 of 25) of primary tumors and 100% (6 of 6) of the metastatic carcinosarcomas, whereas negligible staining was found in normal endometrial cells. Regardless of their resistance to chemotherapeutic agents, all short-term carcinosarcoma cell lines tested died within 1 h of exposure to 3.3 microg/mL of CPE in vitro. Intratumoral injections of well-tolerated doses of CPE in large s.c. carcinosarcoma xenografts led to large areas of tumor cell necrosis and tumor disappearance in all treated animals.
  
  
  CONCLUSIONS
  Claudin-3 and claudin-4 receptors are highly overexpressed in carcinosarcoma. These proteins may offer promising targets for the use of CPE as a novel type-specific therapy against this biologically aggressive variant of endometrial cancer.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199, USA. santinalessandrod@uams.edu
authors.forename: Alessandro D
authors.initials: AD
authors.lastname: Santin
authors.forename: Stefania
authors.initials: S
authors.lastname: Bellone
authors.forename: Eric R
authors.initials: ER
authors.lastname: Siegel
authors.forename: Jesse K
authors.initials: JK
authors.lastname: McKenney
authors.forename: Maria
authors.initials: M
authors.lastname: Thomas
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Roman
authors.forename: Alexander
authors.initials: A
authors.lastname: Burnett
authors.forename: Germana
authors.initials: G
authors.lastname: Tognon
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bandiera
authors.forename: Sergio
authors.initials: S
authors.lastname: Pecorelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002296:Carcinosarcoma / Q000378:metabolism* / Q000382:microbiology*; D062465:Claudin-3; D062506:Claudin-4; D003016:Clostridium perfringens / Q000378:metabolism*; D004768:Enterotoxins / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D016513:Mice, SCID; D008875:Middle Aged; D009368:Neoplasm Transplantation; D014594:Uterine Neoplasms / Q000378:metabolism* / Q000382:microbiology*
chemical_list: C568122:CLDN3 protein, human; C568157:CLDN4 protein, human; D062465:Claudin-3; D062506:Claudin-4; C568123:Cldn3 protein, mouse; C568158:Cldn4 protein, mouse; D004768:Enterotoxins; D008565:Membrane Proteins