Kanser tedavisi için protein mühendisliği yaklaşımları ile geliştirilmiş anti-vegf antikorlarının araştırılması

Monoclonal antibodies (IgGs) are powerful therapeutics for many diseases, including cancer, due to their high specificity and other favorable properties. However, their large size limits their penetration into large masses of biological tissue, such as solid tumors. The single-chain variable fragments (scFvs), on the other hand, have better tissue penetration due to their smaller size. Yet, due to the absence of constant domains, scFvs are not as thermally stable as their parental IgGs or even Fab (fragment antigen-binding) fragments, which poses a challenge for therapeutic applications. Therefore, in this thesis, we aimed to develop a general method for increasing the thermal stability of scFvs. Anti-angiogenic therapy has a critical importance in tumor-mediated angiogenesis, which is a hallmark of solid tumors. Bevacizumab (IgG) was the first therapeutic developed for anti-angiogenic therapy, and it is still used in the clinic for a variety of solid tumor types, mostly in combination with chemotherapy. In this thesis, we developed anti-VEGF scFvs derived from bevacizumab and they demonstrated better anti-angiogenic efficacy compared to bevacizumab on a transgenic zebrafish model. Next, by utilizing rational design approaches including computational methods, and directed evolution techniques including yeast surface display we obtained thermally more stable scFv variants, the highest of which has around 10 ºC higher transition mid-point (T1/2) compared to wild type scFv. This method described in this thesis can be used to improve the thermal stability of any kind of antibody or antibody fragment.