Microneedle-Assisted, DC-Targeted Codelivery of pTRP-2 and Adjuvant of Paclitaxel for Transcutaneous Immunotherapy

This work aims at developing an immunotherapeutic strategy to deliver a cancer DNA vaccine targeting dendritic cells (DCs), to trigger their maturation and antitumor function, and reduce immune escape using a polymeric nanocomplex of paclitaxel (PTX)-encapsulated sulfobutylether-beta-cyclodextrin (SBE)/mannosylated N,N,N-trimethylchitosan (mTMC)/DNA. To enhance DC-targeting and revoke immunosuppression is the major challenge for eliciting effective antitumor immunity. This codelivery system is characterized by using low-dose PTX as an adjuvant that is included inside SBE, and the PTX/SBE further serves as an anionic crosslinker to self-assemble with the cationic mTMC/DNA polyplexes. This system is used in combination with a microneedle for transcutaneous vaccination. Once penetrating into the epidermis, the mannosylated nanocomplexes would preferentially deliver the pTRP-2 DNA vaccine inside the DCs. Phenotypic maturation is demonstrated by the increased expression of costimulatory molecules of CD80 and CD86, and the elevated secretion of IL-12p70. The mixed leucocyte reactions reveal that the PTX/SBE-mTMC/DNA nanocomplexes enhance the proliferation of CD4+ and CD8+ T cells, and inhibit the generation of immune-suppressive FoxP3+ T cells. The system shows high antitumor efficacy in vivo. The PTX/SBE-mTMC/DNA nanocomplexes for DC-targeted codelivery of DNA vaccine and adjuvant PTX yield synergistic effects on the DC maturation and its presenting functions, thus increasing immune stimulation and reducing immune escape.