A biomimetic nanovector-mediated targeted cholesterol-conjugated siRNA delivery for tumor gene therapy.

RNA interference holds tremendous potential as a therapeutic approach of malignant tumors. However, safe and efficient nanovectors are extremely lack for systemic delivery of small interfering RNA (siRNA). The study aimed to develop a biomimetic nanovector, reconstituted high density lipoprotein (rHDL), mediating targeted cholesterol-conjugated siRNA (Chol-siRNA) delivery for Pokemon gene silencing therapy. Chol-siRNA-loaded rHDL nanoparticles (rHDL/Chol-siRNA complexes) were prepared using thin-film dispersion method and their characteristics were investigated in detail. RHDL/Chol-siRNA complexes at the optimal volume ratio (lipid: Chol-siRNA) exhibited high Chol-siRNA-loading efficiency (~99%), desirable nanoparticle size and excellent stability in serum. In addition, by analyzing Chol-siRNA release profile, rHDL/Chol-siRNA complexes displayed sustained-release characteristic and storage stability. Observations from FACS and confocal microscopic analyses revealed that rHDL-mediated carboxyfluorescein tagged Chol-siRNA (FAM-Chol-siRNA) transfection resulted in highly efficient uptake and specific cytoplasmic delivery of FAM-Chol-siRNA into human hepatocellular carcinoma cell line HepG2 via HDL-receptor mediated mechanism. In vitro cytotoxicity, apoptosis and Western-blot analyses revealed significant cellular growth inhibition and decrease of Pokemon and Bcl-2 protein expression in HepG2 cells treated with Chol-siRNA-Pokemon-loaded rHDL nanoparticles (rHDL/Chol-siRNA-Pokemon complexes), respectively. In in vivo studies, the near-infrared (NIR) dye Cy5 labeled Chol-siRNA-loaded rHDL nanoparticles (rHDL/Cy5-Chol-siRNA complexes) obviously accumulated in tumor of nude mice after i.v. administration as compared with Cy5-Chol-siRNA-loaded lipoplexes (Lipos/Cy5-Chol-siRNA complexes). Morover, rHDL/Chol-siRNA-Pokemon complexes demonstrated great tumor growth inhibition and significant decrease of Pokemon and Bcl-2 protein expression in vivo. These results suggested that rHDL should be an ideal non-viral tumor-targeting vector for Chol-siRNA transfer, and rHDL-mediated Chol-siRNA-Pokemon delivery might be a promising new strategy for gene therapy in hepatocellular carcinoma.

Ding Y ，Wang W ，Feng M ，Wang Y ，Zhou J ，Ding X ，Zhou X ，Liu C ，Wang R ，Zhang Q ... -  《-》

Direct cytosolic siRNA delivery by reconstituted high density lipoprotein for target-specific therapy of tumor angiogenesis.

We described here the mechanisms by which small interfering RNA (siRNA) molecules incorporated in reconstituted high density lipoprotein (rHDL) were efficiently transferred into the cytoplasm of cells to perform target-specific therapy of tumor angiogenesis. Using fluorescent-tagged apolipoprotein A-I (apoA-I) and cholesterol-conjugated siRNA (Chol-siRNA), it was confirmed with FACS and confocal microscopic measurements that Chol-siRNA-loaded rHDL nanoparticles (rHDL/Chol-siRNA complexes) were successfully established and apoA-I certainly was attached to the surface of Chol-siRNA-loaded lipoplexes (Lipos/Chol-siRNA complexes). Stably assembled rHDL/Chol-siRNA complexes demonstrated proper nanosize, quasi-spherical shape and improved nuclease protection over naked Chol-siRNA. It was also interesting to note that rHDL provided a highly effective approach to transfer Chol-siRNA across the membrane directly into the cytoplasm via the scavenger receptor BI (SR-BI)-mediated non-endocytotic mechanism, thereby bypassing endo-lysosomal trapping. We also showed clear evidence that the in vitro implementation of rHDL for Chol-siRNA-VEGF (Chol-siRNA targeting vascular endothelial growth factor gene) delivery markedly promoted RNA interference (RNAi)-mediated degradation of VEGF mRNA, resulting in down-regulation of secreted VEGF protein. In vivo fluorescence imaging indicated that near-infrared (NIR) dye Cy5 labeled Chol-siRNA-loaded rHDL nanoparticles (rHDL/Cy5-Chol-siRNA complexes) displayed long circulation time, SR-BI positive tumor-selective targeting, and efficient cytosolic delivery capabilities. Furthermore, intravenous administration of Chol-siRNA-VEGF-loaded rHDL nanoparticles (rHDL/Chol-siRNA-VEGF complexes) significantly enhanced anti-tumor efficacy against breast cancer, decreased VEGF expression level, and inhibited formation of intratumoral microvessels at the tumor tissue. It was concluded that rHDL possessed therapeutic potential and versatility in mediating Chol-siRNA-VEGF direct cytosolic delivery for target-specific anti-angiogenic therapy in breast cancer.

Ding Y ，Wang Y ，Zhou J ，Gu X ，Wang W ，Liu C ，Bao X ，Wang C ，Li Y ，Zhang Q ... -  《-》

Efficient systemic delivery of siRNA by using high-density lipoprotein-mimicking peptide lipid nanoparticles.

Lin Q ，Chen J ，Jin H ，Ng KK ，Yang M ，Cao W ，Ding L ，Zhang Z ，Zheng G ... -  《-》

Low-density lipoprotein-coupled N-succinyl chitosan nanoparticles co-delivering siRNA and doxorubicin for hepatocyte-targeted therapy.

Developing safe and effective carriers of small interference RNA (siRNA) is a significant demand for the systemic delivery of siRNA. In this study, low-density lipoprotein (LDL) was isolated from human plasma and loaded with cholesterol-conjugated siRNA to silence the multidrug resistant gene of tumors. Chol-siRNA/LDL-coupled N-succinyl chitosan nanoparticles loaded with doxorubicin (Dox-siRNA/LDL-SCS-NPs) were then prepared and characterised. The Dox-siRNA/LDL-SCS-NPs had average particle size of 206.4 ± 9.2 nm, entrapment efficiency of 71.06% ± 1.42%, and drug-loading amount of 12.35% ± 0.87%. In vitro antitumor activity revealed that cell growth was significantly inhibited. The accumulation of Dox by fluorescence microscopy and flow cytometry showed that LDL-coupled nanoparticles were more easily taken up than Dox-SCS-NPs. Results of confocal microscopy and reverse transcription-PCR revealed the highly efficient uptake of siRNA and the decrease in mdr1 mRNA expression. LDL-coupled nanoparticles protected siRNA from macrophage phagocytosis by dynamic observation using live cell station. In vivo tumor-targeting suggested that Cy7-labelled Dox-LDL-SCS-NPs were markedly accumulated in an analyzed in situ liver tumor model. Results indicated that LDL-SCS-NPs were effective tumor-targeting vectors and that the preparation form may provide a new strategy for co-delivering siRNA and antitumor drugs.

Zhu QL ，Zhou Y ，Guan M ，Zhou XF ，Yang SD ，Liu Y ，Chen WL ，Zhang CG ，Yuan ZQ ，Liu C ，Zhu AJ ，Zhang XN ... -  《-》

Pokemon siRNA Delivery Mediated by RGD-Modified HBV Core Protein Suppressed the Growth of Hepatocellular Carcinoma.

Kong J ，Liu X ，Jia J ，Wu J ，Wu N ，Chen J ，Fang F ... -  《-》