- 作者：Yoko Hasegawa ; Nobuyuki Oyama ; Keiko Nagase ; Yasuhisa Fujibayashi ; Takako Furukawa ; Yasuko Murayama ; Yoichi Arai ; Seiichi Saito ; Michael J. Welch ; Osamu Yokoyama
- 关键词：RM2 ; Monoclonal antibody ; IgM ; Radioimmunoligand ; Prostate cancer
- 刊名：Nuclear Medicine and Biology
- 出版年：2012
- 出版时间：October, 2012
- 年：2012
- 卷：39
- 期：7
- 页码：944-947
- 全文大小：237 K
Objectives
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 125I 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-¦Â chains expressed on the surface of the prostate cancer cells. 125I-mAb RM2 was added into the cell culture media and cellular uptake of 125I-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 125I-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 125I-mAb RM2 in the PC-3 and LNCaP cells increased according to the incubation time, while the uptake of 125I-mAb RM2 in MCF-7 cells did not show any increase up to 6 hours. The increase of 125I-RM2 uptake was not observed when the PC-3 and LNCaP cells were pre-treated with unlabeled RM2. In the biodistribution studies, 125I-mAb RM2 showed marked uptake into the implanted PC-3 cells. In PC-3 tumor-bearing mice, the tumor muscle ratio of 125I-RM2 was increased for up to 72 hours in a time-dependent manner.
Conclusions
125I-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.