Tumor gene therapy by systemic delivery of plasmid DNA with cell‐penetrating peptides

Gene therapy is a prospective strategy for treating cancer. However, finding efficient and tumor‐specific gene delivery vectors remains an issue. Tumor responsive cell‐penetrating peptide (CPP) PepFect144 (PF144) has previously been shown to deliver reporter gene encoding plasmid DNA specifically into tumors upon systemic administration, but its capability to reduce tumor growth has not yet been evaluated. Here, we study the potential of PF144‐based anti‐angiogenic gene delivery to inhibit tumor growth by silencing vascular endothelial growth factor (VEGF) expression in tumors. This approach led to the inhibition of tumor growth in both the HT1080 fibrosarcoma model and orthotopic 4T1 breast tumor model. We additionally saw that the addition of αvβ3 integrin targeting did not further improve the tumor sensitive CPPs. Our results suggest that activatable cell‐penetrating peptide PF144 is a promising nonviral plasmid DNA delivery vector for cancer treatment.