Antitumor effect of ¹³¹I-labeled anti-VEGFR2 targeted nanoparticles in anaplastic thyroid carcinoma mouse models

Objective: To investigate the radioactivity distribution of ¹³¹I-bovine serum albumin (BSA)-mesoporous silica nanoparticles (MSNs)-anti-vascular endothelial growth factor receptor 2 (VEGFR2) in anaplastic thyroid carcinoma (ATC) and to explore its antitumor efficacy in ATC-bearing nude mouse models. Methods: ¹³¹I-BSA-MSNs-anti-VEGFR2 and ¹³¹I-BSA-MSNs were constructed. FRO tumor xenografts were established and the SPECT/CT images of tumor-bearing mice were acquired at different time points after intratumoral injection with ¹³¹I-BSA-MSNs-anti-VEGFR2 (targeting group), ¹³¹I-BSA-MSNs (non-targeting group), Na¹³¹I (Na¹³¹I group) and saline (control group), respectively. The changes of body mass and tumor volume in each group were recorded. Two-sample t test and log-rank test were used to analyze the data. Results: After incubation for 3 h, the fluorescence intensity in targeting group was higher than that in non-targeting group (345.26 ± 16.35 vs 280.61 ± 9.65; t= 5.90, P < 0.05). After injection for 1-3 weeks, the radioactivity detected by SPECT/CT in targeting group was obviously stronger than that in non-targeting group (t values: 7.060-12.780, all P < 0.05). At the end of the observation, the tumor volume of Na¹³¹I group, control group, non-targeting group and targeting group increased to (278.3 ± 19.3)%, (296.6 ± 24.2)%, (198.7 ± 13.2)% and (103.7 ± 6.2)% of the original volume, respectively. The body mass of the first 2 groups decreased to (88.6 ± 3.0)% and (86.2 ± 3.1)% of the original body mass respectively, while that of the latter 2 groups increased to (102.1 ± 3.1)% and (116.2 ± 3.4)% of the original body mass respectively. Survival analysis showed that the median survival time in targeting group (38 d) was significantly longer than that in non-targeting group (34 d; χ² = 8.05, P < 0.05). Conclusion ¹³¹I-BSA-MSNs-anti-VEGFR2 can effectively inhibit the tumor growth of ATC and prolong the survival of tumor-bearing nude mice, which gives a good suggestion for the treatment and prognosis evaluation of ATC. (authors)