LAUSR

Introduction Murine double minute 2 (MDM2) is an oncogene that is important in tumorigenesis, tumor metastasis and chemotherapy resistance. We aimed to synthesize a molecular imaging probe, 99mTc-HYNIC-siRNA 1489, which could specifically bind to MDM2. The [99mTc]HYNIC-siRNA 1489 molecular probe provided an effective way of assessing MDM2 expression via single-photon emission computed tomography. Method Three siRNAs were designed, and their inhibitory efficiencies were determined using western blots and qRT-PCR. The selected siRNA was labeled with the radionuclide technetium-99m (99mTc) through the chelator HYNIC. The bioactivity and properties of [99mTc]HYNIC-siRNA 1489 were evaluated prior to imaging in mice. Imaging and biodistribution of the probe were used to assess its targeting ability. Results SiRNA 1489, which was labeled with 99mTc, displayed a strong inhibitory effect in Michigan Cancer Foundation-7 cell lines. The radiochemical purity of [99mTc]HYNIC-siRNA 1489 was stable at various temperatures in phosphate-buffered serum and bovine serum. The tumor/muscle ratio in mice injected with [99mTc]HYNIC-siRNA 1489 was higher than that in those injected with the negative control, [99mTc]HYNIC-NC siRNA. The percentage injected dose per gram (%ID/g) of the tumors injected with 99mTc-HYNIC-siRNA 1489 was greater than that of the control group. Conclusion The [99mTc]HYNIC-siRNA 1489 was taken up by the tumor, which had a high level of MDM2. The probe exhibited a sufficient retention time in the tumor. This probe may be an effective strategy for evaluating MDM2 expression and achieving early diagnosis in breast cancer.