Antibody and protein engineering for cancer immunotherapy: advancing targeted and immune modulation therapies

Abstract

Cancer remains one of the most challenging and deadly diseases worldwide due to the complexity of tumor biology and the ability of cancer cells to evade treatment. Despite advancements, cancer remains the second leading cause of death globally. Two major challenges are tumor heterogeneity and the immunosuppressive tumor microenvironment (TME). Tumor heterogeneity, driven by genetic and phenotypic changes, allows cancer cells to lose antigen expression, leading to resistance against single-target therapies. Targeting multiple tumor-specific antigens with antibody cocktails or modulating immune checkpoints that restore immune function in the TME could help overcome these challenges. In this work, we applied directed evolution in yeast and phage display systems to engineer antibodies from human antibody fragment libraries that are specific to neoepitopes in the mouse B16F10 melanoma and CT26 colon carcinoma models. Many of these antibodies showed binding to tumor cells, elicited effector functions, and inhibited tumor growth in mice. Additionally, we explored the engineering of an immune checkpoint blockade antibody for canine oncology that showed promising results in a canine safety trial. Furthermore, we engineered two anti-PD-L2 checkpoint blockade antibodies with distinct receptor-blocking properties to explore how PD-L2 interacts with its binding partners, PD-1 and RGMB, in the context of tumor immunology. The results of these studies highlight the feasibility of engineering patient-customized antibody therapies as a possible solution to overcoming tumor heterogeneity as well as offer immune checkpoint blockade strategies and insight for both human and veterinary oncology. Future work should focus on optimizing these therapies and evaluating their clinical potential in both human and canine cancer treatments