Coptisine enhances the sensitivity of chemoresistant breast cancer cells by inhibiting the function and expression of ABC transporters

Multidrug resistance (MDR), mainly caused by ATP-binding cassette transporters (ABCTs) efflux, makes it difficult for many anticancer drugs to treat breast cancer (BC). Phytochemicals can reverse cancer's MDR by modifying ABC transporter expression and function, as well as working synergistically with anticancer drugs to target other molecules. The reversal effect of the isoquinoline alkaloid coptisine (COP) was assessed on four breast cell lines; Two sensitive MCF-7 cell lines with positive estrogen, androgen, progesterone, and glucocorticoid receptors, as well as MDB-MB-231 cells with negative estrogen, progesterone, and HER2 receptors, and two doxorubicin-resistant cell lines, MCF-7/ADR and MDB-MB-231/ADR.