In conclusion, our study reveals that nanoceria induces a mitochondria-centric cascade of interrelated cellular events in MCF7 breast cancer cells, initiated by excessive ROS generation and antioxidant system collapse, leading to mitochondrial dysfunction, suppression of mitochondrial biogenesis, p53 pathway activation, G0/G1 cell cycle arrest, and global proteomic reprogramming. Here, TP53 is linked to breast carcinoma.