 Abstract, a caffic acid phenethyl ester, CAPE, an active ingredient of propolis extract, has been shown to have a variety of beneficial effects, including reversing chemo-resistance in breast cancer. This study investigates the effects of CAPE on doxorubicin, DOX, resistant breast cancer cells and explores the underlying mechanisms. Results show that CAPE can reverse DOX resistance in breast cancer cells and suppresses lipid metabolism, which is partially mediated by inhibition of ACT-MTO-ARC-SREB-1 pathway. These findings suggest that CAPE could be used as an adjuvant therapy to improve the efficacy of DOX in treating breast cancer. This article was authored by Luchang Liang, Lei Jiao, Bo Yu, and others.