Evaluation of SPECT/CT imaging and internal therapeutic effectiveness of ¹³¹I-RGD-BSA-PCL in the lung cancer mouse model

Objective: To investigate the SPECT/CT imaging of non-small-cell lung carcinoma (NSCLC) mice models and the internal irradiation biological effects and therapeutic effectiveness of nanoliposome ¹³¹I-RGD-BSA-PCL. Methods: RGD-BSA-PCL and BSA-PCL were constructed. The target binding and cellular uptake in H460 cell line were observed by fluorescence confocal microscopy in vitro. The nanoliposome with ¹³¹I were labeled using the Chloramine-T method. Apoptosis analyses was performed using flow cytometry. By construcing tumor xenografts, the biological distribution, change of tumor volume and the SPECT/CT imaging were discussed. Results: Confocal microscopy revealed significant uptake of RGD-BSA-PCL or BSA-PCL in NCI-H460 cell after nanolipsome incubated for 1 and 8 h. The early apoptosis rates of Na¹³¹I, ¹³¹I-BSA-PCL and ¹³¹I-RGD-BSA-PCL were (33.3 ± 12.5)%, (68.4 ± 8.0)% and (70.5 ± 12.2)%, respectively. The tumor uptake levels of ¹³¹I-BSA-PCL were higher than that of ¹³¹I-BSA-PCL (t = 9.53, 5.03, P < 0.01). There was a significant difference of tumor volume between the treatment group and the control group, and the tumor volume inhibition was most obvious in the ¹³¹I-RGD-BSA-PCL group on day 23 post-treatment (t = 126.44, P < 0.01). SPECT/CT tomography showed that ¹³¹I-RGD-BSA-PCL and ¹³¹I-BSA-PCL groups had obvious accumulation in the tumor on day 21 post-treatment, and intensity of radiation signal of ¹³¹I-RGD-BSA-PCL group was stronger than that of ¹³¹I-BSA-PCL group. Conclusions: Radionuclide therapy using ¹³¹I-RGD-BSA-PCL, which showed excellent targeted cell killing and suppressed tumor growth, exhibited favorable intracellular retention of ¹³¹I. (authors)