title: A new model of rectal cancer with regional lymph node metastasis allowing in vivo evaluation by imaging biomarkers.
abstract: OBJECTIVE
  The work is aimed to develop a murine model of rectal cancer, which could be used to monitor lymph node metastasis development by magnetic resonance imaging (MRI) and optical imaging (OI) techniques.
  
  
  METHODS
  Ht-29 cancer cells were directly injected into the submucosal layer of the rectum of athymic nude mice using trans-anal rectal cancer cell injection (TARCI). Thirty-six mice were inoculated with 10×10(5) cells and five mice were treated with sterile phosphate buffer solution. One to 4 weeks after cell injection, tumor growth was evaluated in vivo using T2-weighted MRI at 4.7T. A further group of animal (n=6) treated with ht-29_luc cells, with the same protocol, was monitored by optical imaging. In both groups, the presence of the primary tumor and of lymph nodes metastasis was confirmed by histology.
  
  
  RESULTS
  In all animals, primary tumors were detectable by MRI, 1 week from TARCI. After 4 weeks primary tumors showed a mean longitudinal diameter of about 2cm. All animals developed regional lymph node metastases. Others organs (e.g. lung or liver) were not affected. In fat-suppressed, T2-weighted MRI, lymph nodes appeared as small areas characterized by hyper-intense signal compared to muscle. OI permitted evaluation of the primary tumor growth in perineal region.
  
  
  CONCLUSIONS
  TARCI of ht-29 cells into the rectum of nude mice is a feasible way to obtain a easily reproducible model of regional lymph node metastases could be monitored by magnetic resonance and optical imaging techniques.
authors: First division of general surgery, University of Verona, Verona, Italy.
authors: A M
authors: AM
authors: Minicozzi
authors: G
authors: G
authors: Conti
authors: G
authors: G
authors: Merigo
authors: P
authors: P
authors: Marzola
authors: F
authors: F
authors: Boschi
authors: L
authors: L
authors: Calderan
authors: R
authors: R
authors: Pacca
authors: A
authors: A
authors: Sbarbati
authors: C
authors: C
authors: Cordiano
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D055088:Early Detection of Cancer / Q000379:methods*; D019073:HT29 Cells; D006801:Humans; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D049408:Luminescent Agents; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009368:Neoplasm Transplantation / Q000379:methods; D010865:Pilot Projects; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012007:Rectum / Q000378:metabolism / Q000473:pathology; D015203:Reproducibility of Results; D047368:Tumor Burden
chemical_list: D049408:Luminescent Agents; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; D008156:Luciferases