Progress on internalization study of antibody-drug conjugates

Antibody-drug conjugates (ADC) are complex molecules with cytotoxic small molecular drugs covalently bound to monoclonal antibodies via a linker and combining the antigen-targeting specificity of monoclonal antibodies with the cytotoxic potency of chemotherapeutic drugs. ADC molecules bind to the target antigens expressed on the tumor cell surfaces guided by the monoclonal antibody component. The binding ADC molecules can be internalized and subsequently the toxin moieties can be released within the tumor cells via chemical and/or enzymatic reactions to kill the target cells. Internalization of an ADC is critical to its efficacy and now is an important part of its development stage. But due to the lack of overall understanding of ADC internalization, there are so many challenges in the development of research method about internalization and its mechanism. This review will discuss mechanism, influence factors and common methods and developments of ADC internalization.