TP53 and cancer: The HCT116 p53+/+ cells68,69 possess a cancer stem cell fraction capable of forming colonospheres from single cells, and have been utilized in several studies as a CSC model.70–72 The HCT116 p53+/+ cells were treated with Δ-[Fe2L13]Cl4 and Δ-[Fe2L3a3]Cl4 at their respective IC30 concentrations for 72 h, and subsequently cultured as single cell suspensions in serum-free media.