Programmable Oligonucleotide Delivery System for next-generation siRNA Prostate cancer thErapy

Important results from the project

To determine the invitro therapeutic efficacy of chemically (guanidinium) modified siRNA we have designed a post-synthetic chemically (guanidinium) modified oligonucleotide through hydrazone linkage. As a proof of concept, we introduced our aldehyde modification on STAT3 and CHMP targeting siRNAs with variable aldehydes on the overhang positions. The aldehyde-modified oligonucleotides were subjected to condensation with hydrazide moiety which is linked with guanidinium units and showed a potential gene knockdown capability in cancer cells.

Expected long term effects

We have developed a universal chemical modification strategy to synthesize chemically modified oligonucleotides through post-synthetic modification. In this work, we have synthesized siRNAs with variable aldehyde functionalities which allows the chemical functionalization of any molecule of interest through hydrazone chemistry. We tested this chemical modification on two different siRNAs which showed a comparable knockdown in targeted genes.

Approach and implementation

Initially, the synthesis of the building block required for introducing aldehyde and guanidine functionality on oligonucleotides was optimized separately in our laboratory. Subsequently, the building block was introduced into oligonucleotides of targeting genes were synthesized and purified over time. Later the ligand was conjugated to aldehyde-functionalized oligos through hydrazone chemistry under physiological conditions. After all the guanidine-conjugated oligonucleotides which target STAT3 and CHMP genes were produced and tested on cancer cell lines.