Current status of pH-sensitive liposomes in drug delivery

Epithelial-mesenchymal transition (EMT) is the culprit of tumor invasion and metastasis. As a critical transcription factor that induces EMT, snail is of great importance in tumor progression, and knocking down its expression by small interfering RNA (siRNA) may inhibit tumor metastasis. Herein, we developed a core-shelled bioinspired low-density lipoprotein (bio-LDL) in which snail siRNA-loaded calcium phosphate nanoparticles were wrapped as the core and doxorubicin was embedded in the outer phospholipids modified with a synthetic peptide of apoB100 targeting LDL receptor-abundant tumor cells. Bio-LDL exhibited pH-responsive release, lysosomal escape ability, enhanced cytotoxicity and apoptotic induction. Bio-LDL could significantly inhibit the expression of snail and regulate EMT-related proteins to reduce tumor migration and invasion in vitro. Bio-LDL also displayed favorable tumor targeting and synergistic inhibition of tumor growth and metastasis in vivo. Therefore, the multifunctional bio-LDL will be a promising co-delivery vector and holds potential value for clinical translation.