Design and Synthesis of Shikimoyl-functionalized Cationic Di-block copolypeptide for Cancer Cell Specific Gene Transfection

Abstract

Targeted and efficient gene delivery systems hold tremendous potential for the improvement of cancer therapy by enabling appropriate modification of biological processes. Herein, we report the design and synthesis of a novel cationic di-block copolypeptide, incorporating homoarginine (HAG) and shikimoyl (LSA) functionalities (HDA-b-PHAGm-b-PLSAn), tailored for enhanced gene transfection specifically in cancer cells. The di-block copolypeptide was synthesized via sequential N-carboxyanhydride (NCA) ring-opening polymerization (ROP) techniques and characterized its physicochemical properties, including molecular weight, dispersity, secondary conformation, size, morphology, and surface charge. In contrary to the cationic poly-L-homoarginine, we observed a very less cytotoxic effect of this di-block copolypeptides due to the inclusion of the shikimoyl glyco-polypeptide block, which also added selectivity in internalizing particular cells. This di-block copolypeptide was internalized via mannose-receptor-mediated endocytosis, which was investigated by competitive receptor blocking with mannan. We evaluated the copolypeptide's transfection efficiency in HEK 293T (noncancerous cell), MDA-MB-231 (breast cancer cell), RAW 264.7 (dendritic cell) and compared with commonly employed transfection agents (Lipofectamine). Our findings demonstrate that the homoarginine and shikimoyl-functionalized cationic di-block copolypeptide exhibits potent gene transfection capabilities with minimal cytotoxic effects, particularly in cancer cells, while it is ineffective for normal cells, indicative of its potential as a promising platform for cancer cell-specific gene delivery systems. To evaluate this, we delivered an artificially designed miRNA-plasmid against Hsp90 (amiR-Hsp90) which upon successful transfection depleted the Hsp90 (a chaperone protein responsible for tumor growth) level specifically in cancerous cells and enforced apoptosis. This innovative approach offers a new avenue for the development of targeted therapeutics with improved efficacy and safety profile in cancer treatment.