For example, SIRT-1 inhibitor AMurensin G reduced recombinant forkhead box protein O1 (FoxO1) and multidrug resistance 1 (MDR1) protein levels in doxorubicin-resistant breast cancer cells [123], Psammaplin A can also overcome multidrug resistance of breast cancer cells by inhibiting SIRT-1 and inducing autophagy [124]. This evidence concerns the gene SIRT1 and breast cancer.