Abstract:

Objective   To investigate the biodistribution and significance of 131I- rFliC in breast cancer-bearing mice. Methods   ① The expression of TLR5 was assayed by the immunofluorescence method，RT-PCR and Western blot. ② rFliC was labeled by 131I and the radiochemical purity,  stability,  cell uptake and efflux of 131I- rFliC were identified. ③  MCF-7 bearing mice were prepared and injected with 131I- rFliC. The biodistribution of 131I- rFliC and tumor targeting were analyzed. Results   ① MCF-7 could express TLR5 at the mRNA and protein levels. The expression of TLR5 was down-regulated by rFliC with a dose-dependent manner. ② The labeling efficiency of 131I-rFliC was 95.19% and the radiochemical purity was 96.46%. 131I-rFliC was more stable in serum and could be absorbed by MCF-7 stably. ③ 24h after injection with 131I-rFliC,  T/M ratio was 7.09, and tumor tissue appeared clearly with the autoradiography. Conclusion   Tumor-targeting of 131I -rFliC is obvious,  and it may become a new molecular probe for the diagnosis and therapy of breast cancer.

Key words: Flagellin; Toll-like Receptor 5; Radioactiveiodine; Biodistribution; Breast neoplasm