Development of targeted recombinant polymers that can deliver siRNA to the cytoplasm and plasmid DNA to the cell nucleus

One of the major limitations to effective siRNA delivery is the lack of a siRNA-specific delivery system. Currently, the same delivery systems that are used for plasmid DNA (pDNA) delivery to the cell nucleus are used for siRNA delivery to the cytoplasm. To fill this gap, the objective of this study was to design a biopolymer that can be programmed via its amino acid sequence to deliver siRNA specifically to cytoplasm. For pDNA delivery, a nuclear localization signal (NLS) was added to the biopolymer structure to facilitate active translocation of the genetic material towards nucleus. The biopolymers were complexed with pEGFP and GFP-siRNA and used to transfect SKOV-3 (HER2+) cells. The intracellular trafficking of the nanoparticles was also monitored in real-time and live cells. The results demonstrated that the biopolymer with NLS is a suitable carrier for pDNA delivery but not siRNA delivery. Conversely, the biopolymer without NLS was suitable for siRNA delivery to the cytoplasm but not pDNA to the cell nucleus. The potential use of the designed biopolymer for combination therapy of cancer cells with gene (thymidine kinase) and siRNA (BCL2) was also examined in SKOV-3 cancer cells.

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