RNA interfering is a gene therapeutic approach of great potential for cancer. However, tumor-targeted delivery of small interfering RNA (siRNA) solely based on the enhanced permeability and retention effect of nanocarriers is often insufficient. To address this challenge, siRNA encapsulated ultrasound-responsive microbubble (MB) was developed from polymeric siRNA micelles and liposomal MBs using hetero-assembling strategy. 1MHz low-frequency ultrasound exposure of the tumor site after intratumoral injection of XIAP siRNA/MBs led to enhanced permeability for much more siRNA delivery into deep tumor regions. Significant improvement of XIAP gene silencing and cleaved caspase-3 activation was achieved, resulting in good therapeutic effect on human cervical cancer xenograft model in nude mice. Moreover, real-time US monitoring of the tumor was also possible using the siRNA/MBs as a contrast agent during the therapeutic process. These results show that the multi-functional siRNA/MBs are a promising theranostic system for cancer gene therapy.
Keywords: Contrast-enhanced ultrasound (CEUS); Microbubbles; RNA interfering; XIAP; siRNA-loaded microbubble.
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