It has been previously demonstrated that endogenous proteases can be exploited to safely facilitate activation of membrane disruptive polymer conjugates for safe delivery of RNAi to the cytosol. Para-aminobenzyl carbonate (PABC) incorporated in a conjugate as a self-immolative spacer provides fast kinetics of free amino-group liberation following enzyme triggered cleavage of the anilide bond. This approach, originally proposed by Katzenellenbogen, has been utilized in countless pro-drug type motifs. Although implemented clinically, the PABC moiety is considered a source of potential down stream mutagenesis due to the potent electrophilicity of the quinone imine methide generated during 1,6 elimination. Many examples have been described where regeneration of the parent amine resulted from proteolysis of a peptide sequence lacking the PABC modality. Unfortunately the rate of such proteolysis is often not sufficiently expedient to facilitate endosomal escape of the co-delivered RNAi without sufficient degradation in the nuclease rich environment. In this paper we explore novel protease substrates that can rapidly regenerate the conjugate parent polyamine without reliance on the self-immolative based approach. Kinetics of peptide degradation in-vitro and relation to in-vivo knockdown utilizing the aforementioned conjugate platform will be discussed.

Optimization of peptide substrates for conjugate modification of macromolecular mediated RNAi delivery

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.