Solid phase synthesis and self‐assembly of higher‐order siRNAs and their bioconjugates

Abstract

New methods for the synthesis of higher‐order siRNA motifs and their bioconjugates have recently gained widespread attention in the development of new and improved gene therapeutics. Our efforts aim to produce new chemical tools and protocols for the generation of modified siRNAs that screen for important oncogene targets as well as silence their activity for effective gene therapy in cancer models. More specifically, we have developed an efficient solution‐phase synthesis for the production of a ribouridine branchpoint synthon that can be effectively incorporated by solid phase synthesis within higher‐order RNA structures, including those adopting V‐, and Y‐ and >‐< shape RNA templates. Self‐assembly of complementary RNA to the template strands produced higher‐order siRNA nanostructures that were characterized by a combination of PAGE, DLS, and TEM techniques. In an effort to extend the repertoire of functionally diverse siRNAs, we have also developed solid phase bioconjugation strategies for incorporating bio‐active probes such as fatty acid appendages and fluorescent reporters. Taken together, these methods highlight the ability to generate higher‐order siRNAs and their bioconjugates for exploring the influence of modified siRNA structure on anti‐cancer activity.

Size Matters: Arginine-Derived Peptides Targeting the PSMA Receptor Can Efficiently Complex but Not Transfect siRNA

“…Thus, GRPs have been classified as clinically proven therapeutic targets for specific cancer detection and treatment modalities. Toward this goal, we have developed GRP-silencing siRNA nanostructures 15 , 16 and their bioconjugates17, 18, 19 for potentiating GRP knockdown and cell death in a panel of cancer cell lines. Building upon this work, we now report a peptide formulation capable of efficiently complexing and releasing siRNA, but with limited cell uptake due to aggregation into large, polydisperse anionic nanoparticles.…”