We show that NOTCH3 up-regulates the expression of miR-223 by directly binding to the CSL core element in its promoter, and miR-223 inhibits the translation of ZEB1 by directly binding to the 3' UTR region of ZEB1, which eventually leads to the proliferation, invasion and EMT inhibition of breast cancer cells. The gene discussed is NOTCH3; the disease is breast carcinoma.