Tumor-targeted liposomal RNAi therapy suppresses breast cancer and modulates tumor microenvironment.

Liposomes are widely used nanocarriers, but their clinical translation remains limited by poor tumor selectivity and inefficient nucleic acid delivery. To address these challenges, we designed multifunctional liposomes incorporating phenylboronic acid (PBA) for tumor targeting, ginsenoside Rh2 (Rh2) as both a cholesterol-mimetic stabilizer and intrinsic anticancer agent, and small interfering RNA against vascular endothelial growth factor (VEGF). VEGF was selected for its pivotal role in tumor angiogenesis and to counteract the paradoxical pro-angiogenic effect of Rh2. PBA-modified liposomes exhibited enhanced tumor accumulation and cellular uptake compared with non-targeted controls. Rh2 induced direct cytotoxicity, while VEGF silencing further suppressed angiogenesis together producing synergistic antitumor activity. In vivo, Rh2-PBA-siVEGF liposomes (RhPLIPO-siVEGF) and Rh2-PBA-Negative Control siRNA (siNC) liposomes (RhPLIPO-siNC) were evaluated in a 4T1 orthotopic breast tumor model. Both formulations elicited effects characterized by increased infiltration of T cells and M1 macrophages. Notably, RhPLIPO-siVEGF treatment significantly reduced tumor growth and microvascular density compared with RhPLIPO-siNC, confirming synergy between Rh2-mediated cytotoxicity and VEGF knockdown. Overall, this multifunctional liposomal system integrates tumor targeting, intrinsic cytotoxicity, and RNA interference-mediated anti-angiogenesis with minimal adverse effects, offering a potent and versatile nanoplatform for targeted breast cancer therapy.