Human sodium iodide transporter gene-mediated imaging and therapy of mouse glioma, comparison between 188Re and 131I.

Novel treatment options are urgently required for patients with glioma who are not effectively treated through standard therapy. Human sodium iodide symporter (hNIS) is a molecular target of certain tumors types. Compared with 131I, 188Re possesses a higher energy and shorter half-life; therefore, the effects of 188Re and 131I were compared in hNIS-mediated gene imaging and therapy in the present study. Recombinant human brain glioma cell line U87 was transfected with a recombinant lentiviral vector containing hNIS (U87-hNIS). U87-0 cell line transfected with blank lentivirus was prepared as a control. In vitro, the 188Re and 131I uptake of U87-hNIS cells were 21.3-times and 25.9-times that of the control groups, however the excretion rate of the two nuclides was very rapid, and the half-life was only ~4 min. Sodium perchlorate inhibited hNIS-mediated 188Re and 131I uptake to levels observed in the control groups. 188Re and 131I were able to kill U87-hNIS cells selectively, with a survival of only 21.6 and 36.2%, respectively. U87-hNIS nude mice appeared to accumulate 188Re, with a ratio of radioactivity counts between tumor and non-tumor sites of ~13.5 compared with 10.3 of 131I 1 h after radionuclide injection. In contrast with in vitro studies, U87-hNIS cells demonstrated a notable increase in 188Re retention in vivo, even 24 h after 188Re injection. U87-hNIS cells also exhibited increased 131I retention in vivo; however, as the time increased, 131I was rapidly released with the tumor no longer able to be imaged 24 h after 131I injection. Following treatment, U87-hNIS tumors experienced a volume reduction of 24.1%, whereas U87-0 cells demonstrated an increase of 28.8%. 188Re and 131I were revealed to be effective at decreasing tumor volume compared with the control. However, 188Re was significantly more potent compared with 131I (P<0.01). The present study indicated that the U87-hNIS cell line is sufficient to induce specific 188Re and 131I uptake, which may kill cells in vitro and in vivo. 188Re exhibited an increased retention time in vivo compared with 131I, which facilitates the imaging and therapy of U87-hNIS tumors.