Mad1 mediates hypoxia-induced doxorubicin resistance in colon cancer cells by inhibiting mitochondrial function

► Mad1 was upregulated HIF-1α-dependently in colon cancer cells during hypoxia. ► Mad1 mediated hypoxia-induced tumor resistance to doxorubicin. ► Mad1 lowered doxorubicin-induced reactive oxygen species generation through mitochondrial inhibition. ► Mad1 could be a potential target for sensitizing colon cancer to redox-cycling anticancer drugs.