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Chinese Journal of Clinical Pharmacology and Therapeutics ›› 2020, Vol. 25 ›› Issue (12): 1321-1329.doi: 10.12092/j.issn.1009-2501.2020.12.001

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Study on the specific binding of 68Ga-PSMA-I&T to prostate cancer cells

XIE Yan 1,2, LI Cheng 1, ZHANG Lulu 2, ZHAO Zhenyu 2, HUANG Shanshan 1, WANG Yongsheng 1, TANG Yuanxiang 1, WANG Feng 2   

  1. 1 Department of Nuclear Medicine, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China; 2 Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, Jiangsu, China
  • Received:2020-10-09 Revised:2020-11-20 Online:2020-12-26 Published:2021-01-04

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Abstract: AIM: To synthesize 68Ga-PSMA-I&T for targeted diagnosis of prostate specific membrane antigen (PSMA) and explore its specific binding to LNCaP cells of prostate cancer.  METHODS: 68Ga-PSMA-I&T was synthesized and its labeling rate, radiochemical purity and stability were measured. LNCaP cells were competitively bound with 2-PMPA and 68Ga-PSMA-I&T, and the radioactive uptake values of cells at different time points were calculated. LNCaP cells were then competitively combined with 68Ga-PSM-I&T and PSM-I&T at different concentrations, and the values of cell radioactive uptake values were calculated. The biological distribution experiment of 68Ga-PSM-I&T in ICR mice was conducted, and the radioactive uptake values per gram of tissue were calculated. Dynamic imaging with 68Ga-PSM-I&T micro-PET/CT was performed on ICR mice and LNCaP tumor-bearing mice, and the time radioactive uptake value curve was plotted. Immunochemical staining was performed to observe the expression of PSMA in the tumor tissues of mice. RESULTS: The radioactive labeling rate of 68Ga-PSMA-I&T was (95.4±2.5)%, with the purity more than 99% and the stability in vitro and in vivo was good. The radioactive uptake values of cells at 30 min and 90 min in the binding group and the blocking group were (3.3±0.5)%, (10.2±0.4)%, (0.99±0.03)%, and (1.54±0.05)%, respectively (P<0.001). The semi-inhibitory concentration (IC50) of PSMA-I&T was 38.64 nmol/L. The dynamic imaging of 68Ga-PSMA-I&T micro-PET/CT of tumor-bearing mice showed significant radioactive uptake in tumor tissues at 15 min, with the radioactive uptake of tumor tissues gradually increased with time. Immunochemical staining results showed that the expression of PSMA protein was abundant in the isolated tumor tissues of LNCaP tumor-bearing mice. CONCLUSION: The synthesis of 68Ga-PSMA-I&T was simple and easy, and its radioactive labeling rate and radiochemical purity were high and its stability was good. 68Ga-PSMA-I&T can specifically bind to LNCaP cells, and its distribution in vivo is good. It shows that it is an ideal tracer for targeted diagnosis of prostate cancer.

Key words: 68Ga-PSMA-I&T, prostate cancer, specific binding, diagnosis

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