Inhibitory mechanism of iodine-125 particles against the expression of nerve growth factor in breast cancer cells

Abstract

Objective To investigate the action mechanism of iodine-125 inhibiting the growth of tumors cell by suppressing the expression of nerve growth factor (NGF) in breast cancer. Methods The animal models of breast cancer cells (MCF-7 ) were established by subcutaneously injecting the tumor cells into nude mice. The mice were divided into 8 groups randomly (n =6 in each group) (the control groups contained C7, C14, C21, C28 subgroups; the experimental groups contained T7, T14, T21, T28 subgroups). No-load seeds (0 Bq) were implanted into the control groups, and iodine-125 seeds (14. 8 MBq) were implanted into the experimental groups. The size of tumors was measured every two days and their volumes then were calculated. Morphology was examined separately at 7th, 14th, 21st and 28th day after the implantation of iodine-125 seeds. The mRNA and protein expression levels of NGF were detected by using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Results After iodine-125 seeds were transplanted into the tumors of the experimental groups, tumors grew more slowly, and the tumor inhibition rate was 55. 27%. At the 28th day, the mRNA and protein expression levels of NGF in tumors were significantly decreased in experimental groups as compared with control groups (P ＜ 0. 01).Conclusion It is one of important molecular mechanisms to restrain breast cancer with iodine-125 seeds to decrease the expression of NGF in tumor cells. Key words: Iodine-125 Seeds; Breast carcinoma; NGF