Fig. 8.

Proposed working mechanisms of metformin in cancer cells. Metformin may directly decrease p53 in sensitive cells, which would in turn downregulate expression of its target gene, DEC1, leading to apoptosis. Metformin not only induces cellular apoptosis but also induces ROS generation through repression of mitochondrial respiration and membrane potential to kill cancer cells. Thus, apoptosis, mitochondrial dysfunction, and ROS generation all contribute to the induction of HeLa cell death by metformin