Collagen Binding Polymer-Cytokine Conjugates for Applications in Local Extracellular Matrix Engineering

Abstract

The therapy suppressive tumour microenvironment (TME) continues to hinder anti-cancer therapies. Local delivery of therapeutic proteins, including potentially toxic factors, is increasingly needed to enhance immunotherapeutic bioactivities and minimize systemic toxicity. To this end, we are developing vehicles that immobilize to extracellular matrix (ECM) components upregulated in TME for localization of polymer-grafted bioactive cytokines with tunable degradation rates to control cytokine clearance. The grafted cytokine would be bioactive, and the length of the therapy would be governed by the degradation kinetics of the hydrolytic linker between the cytokine and polymer. The cytokines were expressed and purified, and their biological activity was confirmed. Click chemistry was used to graft the therapeutic proteins and collagen-binding peptides to the copolymer. Production of the therapeutic carriers was confirmed by SEC and fluorescent measurements. Biolayer interferometry and tracking immobilization inside collagen gel confirmed the binding affinity between carriers and collagen type 1. In vitro studies confirmed the bioactivity of the carriers in the presence of T-cells and macrophages. In summary, ECM binding vehicles for local sustained protein release will aid in the local delivery of therapeutic proteins to alter TME and promote immunotherapies. Screens will be conducted in multicellular spheroid models to identify bioactive formulations.