Specific binding between IL-11 analogue c (CGRRAGGSC) and PC-3 cells in vitro

Abstract

Objective To assess the specific binding between interleukin-11 (IL-11) analogue c (CGRRAGGSC) and PC-3 cells in vitro and biostribution in bone metastases of prostate cancer in mice in vivo. Methods The expression changes of IL-11R in PC-3 tumors and normal prostate cells were examined by Western blotting. The binding site of the molecular target and internalization with PC-3 cells was observed under a fluorescence microscope. Twenty-eight tumor-bearing nude mice were divided into 7groups, and radioactive molecular probe 99Tcm-DT-PA- c (CGRRAG-GSC) was radiolabeled with 99Tcm.Biodistribution in nude mice bearing PC-3 tumors was observed and analyzed after intravenous injection of 99Tcm-DTPA-c (CGRRAGGSC) (0.74 MBq/0.2 mi). Results The expression of IL-11R in PC-3tumors group was 2. 2 times as the normal group. The counter stain molecular probe was combined with the PC-3 cell membrane and cytoplasm through fluorescence tracing. Uptake of the imaging probe in the tumor was increased. Radioactivity was abnormally concentrated in the tumor lesions and skeleton. Most apparent after 4 h ( 15. 12 ± 1.19, 7.03 ± 1.83), radiation was not obviously observed in other viscera ( F = 71.58,9. 58 ,P ＜ 0. 05). Conclusion c (CGRRAGGSC) peptide has the specific binding ability in targeting to PC-3 cells in vitro. Radioactive molecular probe 99Tcm-DTPA-c (CGRRAGGSC) has potential as a specific molecular target imaging agent for bone metastasis, such as prostate cancer. Key words: Polypeptide; Tumor/prostate cancer