title: Monoclonal antibody RM2 as a potential ligand for a new immunotracer for prostate cancer imaging.
abstract: OBJECTIVE
  To investigate the potential of monoclonal antibody (mAb) RM2 as a ligand for a radioimmunotracer for prostate cancer imaging.
  
  
  METHODS
  Labeling was conducted with mAb RM2 and (125)I using the chloramine-T method. The cell study was conducted with PC-3 and LNCaP, which are prostate cancer cell lines, and MCF-7, which is a breast cancer cell line. The cells were treated or untreated with unlabeled mAb RM2 to block the haptoglobin-β chains expressed on the surface of the prostate cancer cells. (125)I-mAb RM2 was added into the cell culture media and cellular uptake of (125)I-mAb RM2 was evaluated at 1, 3 and 6 hours of incubation. For the in vivo biodistribution study, PC-3 cells were implanted in athymic male mice. The animals were injected intravenously with (125)I-mAb RM2. At 24, 48 and 72 hours after tracer injection, the animals were sacrificed and the activity levels of blood and tissue samples were determined.
  
  
  RESULTS
  The uptake of (125)I-mAb RM2 in the PC-3 and LNCaP cells increased according to the incubation time, while the uptake of (125)I-mAb RM2 in MCF-7 cells did not show any increase up to 6 hours. The increase of (125)I-RM2 uptake was not observed when the PC-3 and LNCaP cells were pre-treated with unlabeled RM2. In the biodistribution studies, (125)I-mAb RM2 showed marked uptake into the implanted PC-3 cells. In PC-3 tumor-bearing mice, the tumor muscle ratio of (125)I-RM2 was increased for up to 72 hours in a time-dependent manner.
  
  
  CONCLUSIONS
  (125)I-mAb RM2 showed excellent prostate cancer cell targeting in vitro and in vivo. Therefore, mAb RM2 seems to be a potential candidate for an immunoligand for prostate cancer imaging.
authors: Department of Urology, Faculty of Medical Sciences, University of Fukui 910-1193, Fukui, Japan.
authors: Yoko
authors: Y
authors: Hasegawa
authors: Nobuyuki
authors: N
authors: Oyama
authors: Keiko
authors: K
authors: Nagase
authors: Yasuhisa
authors: Y
authors: Fujibayashi
authors: Takako
authors: T
authors: Furukawa
authors: Yasuko
authors: Y
authors: Murayama
authors: Yoichi
authors: Y
authors: Arai
authors: Seiichi
authors: S
authors: Saito
authors: Michael J
authors: MJ
authors: Welch
authors: Osamu
authors: O
authors: Yokoyama
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000493:pharmacokinetics; D002240:Carbohydrate Sequence; D045744:Cell Line, Tumor; D005732:Gangliosides / Q000737:chemistry / Q000276:immunology; D006801:Humans; D018796:Immunoconjugates / Q000276:immunology / Q000493:pharmacokinetics; D007457:Iodine Radioisotopes; D008024:Ligands; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D011849:Radioactive Tracers
chemical_list: D000911:Antibodies, Monoclonal; D005732:Gangliosides; D018796:Immunoconjugates; D007457:Iodine Radioisotopes; D008024:Ligands; D011849:Radioactive Tracers