QSOX1 is a secreted disulfide catalyst that is over-produced in many adenocarcinomas. We have developed a monoclonal antibody that binds and inhibits QSOX1 with an inhibition constant of about 1 nM. The antibody blocks the first step in the QSOX1 dithiol/disulfide relay mechanism by binding to the redox-active site that engages substrates. We have shown that this antibody slows tumor growth and metastasis in breast cancer mouse models. In collaboration with the lab of Sarel Fleishman, we produced a humanized version of the QSOX1 inhibitory antibody to facilitate potential therapeutic applications.
