NDUFS3 and osteosarcoma: The nuclear-encoded NDUFS3 gene was knocked-out to induce CI deficiency in mesenchymal (osteosarcoma 143B) and epithelial (colorectal cancer HCT116) cancer cells, hereafter referred to as 143B−/− and HCT−/− (Supplementary Fig. 1), with the aim to generalize our findings in two cancer models of different tissue origin.