01-01: Polymerization of Quinine for Applications in Gene Therapy
Craig Van Bruggen, David Punihaole, Andrew J. Schmitz, Samantha Linn, Jeffrey M. Ting, Yogesh K. Dhande, Zhe Tan, Mitra Ganewatta, Renee R. Frontiera, and Theresa M. Reineke
University of Minnesota, Twin Cities, St. Paul, MinnesotaRead Abstract
Although the medical community is quickly embracing gene editing technologies, such as CRISPR/Cas9, for the development of new gene therapies, there are still significant drawbacks to current gene delivery methods which often focus on viral vectors. A promising alternative to viral vectors include polymer-based gene delivery. Cationic polymers can electrostatically bind with negatively-charged DNA to form nano-scaled complexes, called polyplexes, which shuttle DNA into cells via endocytosis in a process known as transfection.
Although many types of polymers have been made to increase internalization of DNA into human cells, efficient expression of the DNA is often limited by polyplex entrapment in degradative endosomes. Quinine, a naturally-sourced antimalarial with potential endosomolytic behavior, was polymerized with a variety of hydrophilic comonomers via free radical copolymerization in order to create a more effective polymer-based transfection reagent.
A small library of statistical copolymers containing quinine was screened for hits that can efficiently bind DNA, form polyplexes, and transfect several human cell lines in vitro. A copolymer of 2-hydroxyethyl acrylate (HEA) and quinine, poly(HEA-co-quinine), showed an exceptional ability to transfect both adherent and suspension human cell types with a GFP plasmid at levels comparable to commercial reagents, such as Lipofectamine or JetPEI, with limited cytotoxicity. Genome editing of HEK-293T cells in vitro with CRISPR/Cas9-encoding plasmids was enhanced when using poly(HEA-co-quinine) as a transfection reagent compared to commercial reagents.
In addition, preliminary work has shown that quinine’s unique fluorescence and Raman activity, makes poly(HEA-co-quinine) well suited as a dual-threat therapy agent and diagnostic probe for understanding the polymer’s DNA-binding behavior, trafficking within the cell, and the mechanisms by which it enhances transfection. Through this work, quinine’s storied utility in medicine and synthetic chemistry is broadened as it becomes a potential new tool in the field of gene delivery.