MAIT-203 acetate is a cyclopentyalanin-derived peptidomimetic, potently inhibits the interaction of adenomatous polyposis coli ( APC ) and Asef (RhoGEF4), but not APC-Sam68 or APC-striatin interactions. MAIT-203 acetate binds APC-ARM with a K i value of 0.015 μM and a K d value of 0.036 μM. MAIT-203 acetate significantly represses the migration and invasion of colorectal cancer cells.