Delivery of siRNA Using CXCR4-targeted Nanoparticles Modulates Tumor Microenvironment and Achieves a Potent Antitumor Response in Liver Cancer.

Antiangiogenic therapy has recently emerged as a highly promising therapeutic strategy for treating hepatocellular carcinoma (HCC). However, the only clinically approved systemic antiangiogenic agent for advanced HCC is sorafenib, which exerts considerable toxicity. Moreover, acquired resistance to antiangiogenic therapy often develops and restricts the therapeutic efficacy of this treatment. Hence, in this study, we develop a CXCR4-targeted lipid-based nanoparticle (NP) formulation to specifically deliver vascular endothelial growth factor (VEGF) siRNA as an antiangiogenic substance into HCC. AMD3100, a CXCR4 antagonist, is added into NPs to serve as both a targeting moiety and a sensitizer to antiangiogenic therapy. We demonstrate that AMD-modified NPs (AMD-NPs) can efficiently deliver VEGF siRNAs into HCC and downregulate VEGF expression in vitro and in vivo. Despite the upregulation of the SDF1α/CXCR4 axis upon the induction of hypoxia after antiangiogenic therapy, CXCR4 inhibition by AMD-NPs in combination with either conventional sorafenib treatment or VEGF siRNA prevents the infiltration of tumor-associated macrophages. These dual treatments also induce synergistic antiangiogenic effects and suppress local and distant tumor growth in HCC. In conclusion, the tumor-targeted multifunctional AMD-NPs that co-deliver VEGF siRNA and AMD3100 provide an effective approach for overcoming tumor evasion of antiangiogenic therapy, leading to delayed tumor progression in HCC.