“…As a typical heavy metal ion, Cd 2+ are believed to enter cells via ion channels and bind non-specifically to sulfhydryl groups to dysregulate multiple cellular functions to ultimately produce cytotoxicity depending on the Cd concentration, duration of exposure, and cell type (Rani, Kumar, Lal, & Pant, 2014). Cytotoxicity of DOX, on the other hand, relies on topoisomerase inhibition, DNA intercalation, and ROS generation in cancer cells (Al-Abbasi et al, 2016;Swift et al, 2008). Nevertheless, both Cd 2+ and DOX have been found to induce the expression of P-gp in mammalian cells (Tian et al, 2017) and MDR cancer cells (Mariagrazia et al, 1996;Toffoli, Corona, Gigante, & Boiocchi, 1996), respectively.…”