DIF-3 reduces the expression levels of cyclin D1 and c-Myc by facilitating their degradation via activation of GSK-3β. DIF-3 inhibits Wnt/β-catenin signaling pathway-related proteins in DLD-1 cells. DIF-3 exerts a strong antiproliferative effect on the human cervical cancer cell line HeLa by inducing cyclin D1 degradation and inhibiting cyclin D1 mRNA expression.