SIRT1 and breast cancer: Furthermore, another research group investigated the effect of SIRT1 inhibition by SIRT1 siRNA on EMT-related proteins (vimentin, snail-1, and E-cadherin) in MDA-MB-231, MDA-MB-436, and MDA-MB-468 breast cancer cell lines and found that the siRNA inhibition of SIRT1 downregulated the expression of vimentin (a protein required for cell migration, motility, and adhesion) and snail-1 (a repressor of E-cadherin) but upregulated the expression of E-cadherin (a cell-cell adhesion molecule), indicating that SIRT1 induces the invasion of breast cancer cells by modulating the EMT pathway [56].