Decursin in Angelica gigas Nakai (AGN) Enhances Doxorubicin Chemosensitivity in NCI/ADR‐RES Ovarian Cancer Cells via Inhibition of P‐glycoprotein Expression

Angelica gigas Nakai (AGN, Korean Dang‐gui) is traditionally used for the treatment of various diseases including cancer. Here, we investigated multidrug‐resistant phenotype‐reversal activities of AGN and its compounds (decursin, ferulic acid, and nodakenin) in doxorubicin‐resistant NCI/ADR‐RES ovarian cancer cells. Our results showed that a combination of doxorubicin with either AGN or decursin inhibited a proliferation of NCI/ADR‐RES cells. These combinations increased the number of cells at sub‐G1 phase when cells were stained with Annexin V‐fluorescein isothiocyanate. We also found that these combinations activated caspase‐9, caspase‐8, and caspase‐3 and increased cleaved PARP level. Moreover, an inhibition of P‐glycoprotein expression by either AGN or decursin resulted in a reduction of its activity in NCI/ADR‐RES cells. Therefore, our data demonstrate that decursin in AGN inhibits doxorubicin‐resistant ovarian cancer cell proliferation and induces apoptosis in the presence of doxorubicin via blocking P‐glycoprotein expression. Therefore, AGN would be a potentially novel treatment option for multidrug‐resistant tumors by sensitizing to anticancer agents. Copyright © 2016 John Wiley & Sons, Ltd.