Oncolytic Adenovirus Complexes Coated with Lipids and Calcium Phosphate for Cancer Gene Therapy.

Oncolytic adenovirus (OncoAd ) is a promising therapeutic agent for treating cancer. However, the therapeutic potential of OncoAd is hindered by hepatic sequestration and the host immune response in vivo. Here, we constructed a PEG/Lipids/calcium phosphate (CaP)-OncoAd (PLC-OncoAd ) delivery system for ZD55-IL-24, an oncolytic adenovirus that carries the IL-24 gene. The negatively charged PLC-ZD55-IL-24 were disperse and resisted serum-induced aggregation. Compared to naked ZD55-IL-24, the systemic administration of PLC-ZD55-IL-24 in BALB/c mice resulted in reduced liver sequestration and systemic toxicity and evaded the innate immune response. In addition, masking the surface of OncoAd protected it from neutralization by pre-existing neutralizing antibody. PLC-OncoAd achieved efficient targeted delivery in Huh-7-bearing nude mice, and intravenous administration of a high dose of PLC-ZD55-IL-24 increased therapeutic efficacy without inducing toxicity. The developed PLC-OncoAd delivery system represents a promising improvement for oncolytic adenovirus-based cancer gene therapy in vivo.