Oxidative Stress Promotes Doxorubicin-Induced Pgp and BCRP Expression in Colon Cancer Cells Under Hypoxic Conditions

P‐glycoprotein (Pgp) and breast cancer resistance protein (BCRP) are ATP binding cassette (ABC) transporters that are overexpressed in different drug‐resistant cancer cell lines. In this study, we investigated whether doxorubicin promotes Pgp and/or BCRP expression to induce drug resistance in colon cancer cells under hypoxic conditions. We analyzed HIF‐1α activity via ELISA, Pgp, and BCRP expression by qRT‐PCR and the relationship between doxorubicin uptake and ABC transporter expression via confocal microscopy in HT‐29WT and HT‐29 doxorubicin‐resistant colon cancer cells (HT‐29DxR). These cells were treated with doxorubicin and/or CoCl2 (chemical hypoxia), and reactive oxygen species inductors