Anti-tumor effects of 125I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice

Objective: To study the anti-tumor effects of 125I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice and clarify their anti-tumor mechanisms. Methods 120 nude mice transplantated with human breast cancer cells MCF-7 were randomly divided into 3 groups (n=40): 125I radioactive particles implanted group, non-radioactive particles implanted group and non-particles implanted group. The articles were implanted into mice according to Pairs system principle. The expressions of Fas mRNA and protein and the activaties of caspase-3 and caspase-8 enzyme were detected by RT-PCR and Western blotting. The changes of cell cycle were detected by flow cytometry. Results: Compared with non-radioactive particles implanted group and non-particles implanted group, the size of cancer tissues in 125I radioactive particles implanted group was reduced significantly (P<0.05). The expressions of Fas mRNA, Fas protein, caspase-3 and caspase-8 were increased remarkably (P<0.05). The expressions of caspase-3 and caspase-8 were more than 0.6. The flow cytometry results showed that the number of cells in G0/G1 phase was significantly increased (P<0.05) while the number of cells in S phase was decreased remarkably (P<0.05). Conclusion: The implantation of 125I radioactive particles into transplantated tumor model of human breast cancer cells can kill tumor cells, inhibit the growth cycle of tumor cells and induce the apoptosis of tumor cells in nude mice. (authors)