Chemically Programmed Bispecific Antibody Targeting Legumain Protease and αvβ3 Integrin Mediates Strong Antitumor Effects.

A chemically programmed bispecific antibody (cp-bsAb) that targeted cysteine protease legumain and αvβ3 integrin has been prepared using the aldolase antibody chemical programming (AACP) strategy. In vitro evaluation of the anti-legumain, anti-integrin cp-bsAb and its comparison with cpAbs targeting either integrin or legumain have shown that the former possesses superior functions, including receptor binding and inhibitory effects on cell proliferation as well as capillary tube formation, among all three cpAbs. The anti-legumain, anti-integrin cp-bsAb also inhibited growth of primary tumor more effectively than either anti-legumain or anti-integrin cpAb as observed in the MDA-MB-231 human breast cancer mouse model. The AACP-based cp-bsAb, which contains a generic aldolase antibody, can also serve as a suitable platform for combination therapy, where two equally potent compounds are used to target extracellular receptors.