A novel 99Tcm labelled polypeptide analogue for interleukin-11 receptor imaging in a bone metastases model for prostate cancer
10.3760/cma.j.issn.0253-9780.2010.06.013
- VernacularTitle:99Tcm-DTPA-环九肽用于前列腺癌骨转移白细胞介素11受体显像的实验研究
- Author:
Qing-hua, WU
;
Lu, LIU
;
Qing-juan, HUANG
;
Ze-xuan, YANG
;
Jin, SUN
;
Biao, LIU
- Publication Type:Journal Article
- Keywords:
Peptides,cyclic;
Technetium;
Receptors,interleukin-ll;
Prostatic neoplasms;
Neoplasm metastasis;
Skeleton;
Radionuclide imaging;
Mice
- From:Chinese Journal of Nuclear Medicine
2010;30(6):404-409
- CountryChina
- Language:Chinese
-
Abstract:
Objective To assess the feasibility of a novel 99Tcm labelled polypeptide analogue for interleukin-11 receptor ( IL11R) imaging in a bone metastases model for prostate cancer. Methods A novel circular polypeptide analogue of IL11 ( c( CGRRAGGSC ) ) was indirectly labeled with 99Tcm and the product was named as 99Tcm-DTPA-IL11 RR. The labeling efficiency, radiochemical purity and stability of the product were measured with paper chromatography and high performance liquid chromatography (HPLC). The biodistribution of 99Tcm-DTPA-IL11RR was investigated in 28 ICR normal mice. The organ radioactivity was measured as percentage activity of injection dose per gram of tissue ( %ID/g). The models of bone metastases from prostate cancer were established at the tibias of BALB/c nude mice bearing human prostate cancer PC-3 cells. The tumor bearing ( n= 5 ) and standard closed fracture nude mice models underwent both 99Tcm-DTPA-IL11RR and 99Tcm-methylene diphosphonate (MDP) scintigraphy study. The images were acquired at 0.5, 1,2, 4, 6, 8, 24 h after intravenous injection of the tracers. The competitive inhibition imaging was perfomed in three tumor bearing mice. One-way variance analysis was used. Results The labeling efficiency was 90.7%. The radiochemical purity of 99Tcm-DTPA-IL11RR in normal saline solution was (99.57 ±0.09)%, (99.29 ±0.18)%, (98.95 ±0.78)%, (98.67 ±0.11)%, (96.53 ±0.91)%, (95.20±0.70)%, (88.38 ±0.22)% and (36.17±1.29)% at room temperature after0, 1,2, 3, 4, 6, 8 and 24 h, respectively. The tracer radiochemical purity in the blood of ICR mice remained over 90% at 37 C for 6 h. The labeling compounds were excreted mainly through kidney. The peak uptake of bone ( ( 1.910 ±0.109) %ID/g) and liver ( (0.366 ±0.030) %ID/g) was at 4 h after injection. In the tumor bearing mice, the uptake of spine marrow and large joints of extremities was mild. The highest uptake at tumor region was at 4 h and persistent at 6-8 h after injection. The tumor to non-tumor ratios (T/NT) were 1.17 ±0.17, 2.20 ±0.29, 3.20 ±0.15, 3.67 ±0.23, 13.61±0.85, 9.45 ±0.37 and 3.33 ±0.30 at 0.5,1, 2, 4, 6, 8 and 24 h, respectively (F=621.54, P＜0.05). In the standard closed fracture models,high uptake of 99Tcm-MDP was shown at the fracture site, with no increased 99Tcm-DTPA-IL11RR uptake noted. The tumor uptake was significantly depressed after a pre-injection of the unlabeled polypeptide analogue. Conclusions The synthesis of 99Tcm-DTPA-IL11RR is stable and the labeling efficiency is high. It may be a potential molecular probe in metastatic bone imaging for prostate cancer.
