title: Claudin-4 SPECT Imaging Allows Detection of Aplastic Lesions in a Mouse Model of Breast Cancer.
abstract: The expression of claudin-4, a protein involved in tight junction complexes, is widely dysregulated in epithelial malignancies. Claudin-4 is overexpressed in several premalignant precursor lesions, including those of cancers of the breast, pancreas, and prostate, and is associated with poor survival. A noncytotoxic C-terminal fragment of Clostridium perfringens enterotoxin (cCPE) is a natural ligand for claudin-4. Here, we demonstrate whole-body quantitative SPECT imaging of preneoplastic breast cancer tissue using (111)In-labeled cCPE.
  
  
  METHODS
  cCPE.GST or GST (GST is glutathione S-transferase) was conjugated to the metal ion chelator benzyl-diethylenetriaminepentaacetic acid to allow (111)In radiolabeling. The affinity of radiolabeled cCPE.GST for claudin-4 was confirmed using claudin-4-expressing MDA-MB-468 and SQ20b cells, compared with claudin-4-negative HT1080 cells. In vivo SPECT imaging was performed using athymic mice bearing MDA-MB-468 or HT1080 xenografts and using genetically modified BALB/neuT mice, which spontaneously develop claudin-4-expressing breast cancer lesions.
  
  
  RESULTS
  The uptake of (111)In-cCPE.GST in claudin-4-positive MDA-MB-468 xenograft tumors in athymic mice was significantly higher than in (111)In-GST or claudin-4-negative HT1080 tumors (6.72 ± 0.18 vs. 3.88 ± 1.00 vs. 2.36 ± 1.25 percentage injected dose per gram [%ID/g]; P < 0.0001). No other significant differences were observed in any of the examined organs. BALB/neuT mice, expressing rat neuT under mmtv promotor control, spontaneously developed tumorous lesions within their mammary fat pads over the course of 130 d. Overt mammary tumors were claudin-4-positive, and (111)In-cCPE.GST uptake was 3.2 ± 0.70 %ID/g, significantly higher than (111)In-GST (1.00 ± 0.60 %ID/g; P < 0.05). Mammary fat pads in mice aged 80 d bore claudin-4-positive aplastic lesions and accumulated (111)In-cCPE.GST (3.17 ± 0.51 %ID/g) but not (111)In-GST (0.99 ± 0.39 %ID/g; P < 0.001).
  
  
  CONCLUSIONS
  Taken together, (111)In-cCPE.GST targets claudin-4 expression in frank tumors and preneoplastic tissue, and cCPE imaging may be used as an early detection tool for breast, prostate, and pancreatic cancer.
authors.affiliation: CR-UK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Mosley
authors.affiliation: CR-UK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Knight
authors.affiliation: Department of Gastroenterology II, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Neesse
authors.affiliation: Department of Gastroenterology, Endocrinology, Infectiology and Metabolism, Philipps University Marburg, Marburg, Germany; and.
authors.forename: Patrick
authors.initials: P
authors.lastname: Michl
authors.affiliation: Department of Medicine and Aging Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Iezzi
authors.affiliation: CR-UK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, United Kingdom.
authors.forename: Veerle
authors.initials: V
authors.lastname: Kersemans
authors.affiliation: CR-UK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, United Kingdom bart.cornelissen@oncology.ox.ac.uk.
authors.forename: Bart
authors.initials: B
authors.lastname: Cornelissen
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D062506:Claudin-4 / Q000378:metabolism*; D004195:Disease Models, Animal; D004768:Enterotoxins / Q000378:metabolism; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000378:metabolism; D051379:Mice; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D062506:Claudin-4; D004768:Enterotoxins; D007205:Indium Radioisotopes; C035598:enterotoxin, Clostridium
keywords: SPECT; breast cancer; cCPE; claudin-4; tumorigenesis