trans-Trimethoxyresveratrol (MR-3) is a methoxylated resveratrol derivative that suppresses breast cancer cell invasion. It functions by inhibiting PI3K/Akt and Wnt/beta-catenin pathways and reversing epithelial-mesenchymal transition (EMT). This small molecule is a valuable research tool for studying metastasis and signaling in in vitro cancer models.