Experimental study of vascular endothelial growth factor receptor 2 and integrin α vβ 3 dual-targeted microbubble to assess tumor angiogenesis of renal cell carcinoma in vivo / 中华超声影像学杂志

ABSTRACT

Objective:To evaluate the ability of vascular endothelial growth factor receptor 2(VEGFR2)/integrin α vβ 3 dual-targeted microubble (MBD) to target angiogenesis of renal cell carcinoma (RCC) in vivo. Methods:Non-targeted microbubble (MBN) USphere LA was employed as a template to prepare single- and dual-targeted microbubbles which could bind VEGFR2 and/or integrin α vβ 3 (MBV and MBI) by the biotin-avidin bridging method. A total of 40 RCC nude mice models were established by subcutaneously injecting 786-O cells.Twenty of the models were all injected with MBN, MBV, MBI and MBD in a random order, and the other 20 models were registered for antibody blocking assays. The results of ultrasound images were used for quantitative analyses, and the following quantitative parameters were obtained: intensity increment (a 1), peak halving speed (a 2), curve rising slope (a 3), perfusion time (t 0), time to peak (TTP), peak intensity (PI), mean transit time (MTT) and area under the curve (AUC) for the first three minutes, peak intensity at 10 s before (P 1) and after (P 2) ultrasound destruction, and the differences of tissue enhancement (dTE) between P 1 and P 2 (dTE=P 1-P 2). All the quantitative parameters of four contrast agents and the antibody blocking assays were compared.Besides, the immunohistochemical assays were performed to evaluate the expression of CD31, VEGFR2 and integrin α vβ 3 in tumor tissues. Results:The differences of parameters of a 1, a 3, t 0, TTP, PI and P 2 among four different microbubbles had no statistical significances (all P>0.05), and all parameters between the two single-targeted contrast agents were not statistically different (all P>0.05). The parameters of AUC, MTT, P 1 and dTE all showed a trend that dual-targeted bubbles > single-targeted bubbles > non-targeted bubbles (all P<0.05). On the contrary, the trend of dual-targeted bubbles < single-targeted bubbles < non-targeted bubbles (all P<0.05) was observed for a 2. In the antibody blocking experiment, a 2 was faster after the antibody injection ( P<0.001), while AUC, MTT, P 1 and dTE were all lower than those before the antibody injection ( P<0.001), and the other parameters were not statistically different before and after the antibody injection (all P>0.05). Immunohistochemical analyses confirmed the high expression of CD31, VEGFR2 and integrin β 3 in tumor tissues. Conclusions:The VEGFR2 and integrin α vβ 3 dual-targeted microbubble has a good potential to target the angiogenesis of human RCC in vivo.