File:Molecules-26-07294-g002-550.webp

English: Figure 2. Mechanism of action of Sacituzumab govitecan. The humanized monoclonal antibody (hRS7) allows the internalization of the cytotoxic payload (SN38) into the tumor cell after binding with the surface receptor Trop-2. The hRS7 complex bound to Trop-2 is internalized through an endosomal vesicle that carries it to the lysosomes. Free SN-38, released after antibody catabolism and linker hydrolysis within the lysosome, induces DNA damage due to the inhibition of topoisomerase 1. Furthermore, the hydrolyzable linker enables SN-38 to be released into the tumor microenvironment. Given its membrane-permeable nature, free SN-38 can also exert its effect on neighboring cancer cells. Thus, tumor cells that express Trop-2 on the surface undergo the cytotoxic effect of SG by the intracellular uptake of SN38, whereas the adjacent ones experience this effect by its extracellular release (the so-called bystander effect).