The Role of the Furin‐Cleavable Linker and KDEL Sequence in Cytotoxicity of Recombinant ImmunoDNase

Abstract

The lack of specificity of standard chemotherapies to identify and kill cancer cells has challenged researchers to engineer targeted therapies to replace conventional treatments. One strategy that is currently being optimized to treat cancer is the use of recombinant immunotoxins (RITs). RITs are chimeric proteins that are engineered to contain an antibody conjugated to a toxin. The antibody allows for specific targeting of cancer cells while the toxin domain is internalized by the targeted cell and subsequently induces cell death. These therapies suffer from several problems, including non‐specific toxicities, low anti‐tumor activity, and immunogenicity. A bacterial moiety introduced into a patient with an intact immune system can elicit an immune response that consequently eliminates the possibility of retreatment. Deimmunized, humanized, and fully human immunoconjugates have been engineered, but often lack efficacy. We are using specific sequences known to assist cellular intoxication by Pseudomonas exotoxin A (PE) to enhance the activity of human‐derived immunotoxins. We are developing a recombinant immunotoxin based on human DNase I, using a furin‐cleavable linker and KDEL ER retention sequence adapted from the PE intoxication strategy. We expect this construct to have low immunogenicity, high specificity for dividing cells, and enhanced toxicity relative to the unmodified DNase I construct.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.