A dissolvable microneedle platform for the delivery of tumor-derived total RNA nanovaccines for enhanced tumor immunotherapy.

Tumor-derived total RNA (TdRNA) vaccines induce broad immune responses by either synthesizing tumor-specific antigens or activating pattern recognition receptors, making them a promising tool in cancer immunotherapy for the activation of cytotoxic T lymphocytes (CTLs). However, TdRNA vaccines face issues such as low stability and inadequate immune activation. To overcome these challenges, we have developed a dissolvable microneedle delivery platform, PTC NVs@MNs, designed for the simultaneous delivery of TdRNA and CpG oligodeoxynucleotides (CpG ODN). This platform stabilizes TdRNA, maintaining its activity for up to 30 days at room temperature and promotes dendritic cell maturation, and then activates T lymphocyte-mediated antitumor immunity through the targeted delivery of TdRNA and CpG. PTC NVs@MNs not only enhance dendritic cell maturation and increase CD8⁺ T cell infiltration into tumors, eliciting robust antitumor immune responses that inhibit tumor growth, but also induce antitumor immune memory to prevent tumor development. This innovative approach offers therapeutic and preventive benefits in tumor management. STATEMENT OF SIGNIFICANCE: Tumor-derived total RNA (TdRNA) holds potential for eliciting a broad immune response; however, its therapeutic efficacy against triple-negative breast cancer (TNBC) is constrained by low stability and inadequate immune activation. To overcome these limitations, we engineered a dissolving microneedle patch for transdermal co-delivery of TdRNA and CpG oligodeoxynucleotides (CpG ODN). This system not only stabilizes TdRNA-maintaining its bioactivity for 30 days at room temperature-but also promotes dendritic cell maturation and activates T lymphocyte-mediated antitumor immunity . This study demonstrated that the well-designed microneedle patch effectively prevents RNA degradation without requiring stringent storage conditions, offering both therapeutic and preventive benefits in tumor management.