Doxorubicin-resistant BT-549 (BT-549<sup>r</sup>DOX<sup>20</sup>) and 5-Fluorouracil-resistant MDA-MB-468 (MDA-MB-468<sup>r</sup>5-FU<sup>2000</sup>) cells were chosen for further analysis with the autophagy inhibitor Bafilomycin A1 and lentiviral depletion of ATG5, indicating that enhanced cytoprotective autophagy partially contributes to increased drug resistance and cell survival.