title: Neurotensin receptors in adeno- and squamous cell carcinoma.
abstract: BACKGROUND
  Peptide receptors seem to be good markers for receptor targeting because of their overexpression in human cancer. Understanding the role of receptors and their cognate ligands, they are currently used for both diagnosis and therapy. Candidates playing a key role in tumor biology are the neurotensin receptors (NTR). The expression of NTR in HT-29 cells (human colon adenocarcinoma cell line), FaDu cells (human squamous cell carcinoma cell line) and in corresponding tumor xenografts on nude mice, was investigated.
  
  
  METHODS
  Quantitative RT-PCR of the three receptor subtypes was carried out to study mRNA expression. Receptor protein expression was analyzed by immunohistochemistry with specific antibodies for the three known neurotensin receptors NTR1, NTR2 and NTR3.
  
  
  RESULTS
  Analysis of receptor mRNA revealed a strong expression of NTR3 and a weak expression of NTR1 and NTR2 in cultured cells and xenografts. Examining the protein levels, a strong signal for NTR1 was detected in tumor cells and xenografts and only a weak signal was detected for NTR3.
  
  
  CONCLUSIONS
  Since the receptor protein is targeted in vivo, the enhanced protein expression of NTR1 in xenografts could be a useful tool for molecular targeting with radioligands and for further characterization of the carcinogenic process.
authors.affiliation: Department of Radiopharmaceutical Biology, Institute of Radiopharmacy, Research Center Rossendorf, POB 51 01 19, 01314 Dresden, Germany. c.haase@fz-rossendorf.de
authors.forename: C
authors.initials: C
authors.lastname: Haase
authors.forename: R
authors.initials: R
authors.lastname: Bergmann
authors.forename: J
authors.initials: J
authors.lastname: Oswald
authors.forename: D
authors.initials: D
authors.lastname: Zips
authors.forename: J
authors.initials: J
authors.lastname: Pietzsch
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002087:Butyrates / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism; D005260:Female; D019073:HT29 Cells; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008819:Mice, Nude; D018028:Receptors, Neurotensin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D002087:Butyrates; C490985:NTSR2 protein, human; C490984:Ntsr2 protein, mouse; D018028:Receptors, Neurotensin; C114036:neurotensin type 1 receptor