HMOX1 and cancer: Subsequently, the same group, using human cancer cell lines expressing different forms of p53, demonstrated that Metformin was able to induce miR-34a and to suppress the SIRT1/PGC-1α/PPARγ-mediated transcription of the NRF2 gene, leading to decreased expression of SOD2 and HMOX1 and augmented sensitivity of wild-type p53 cancer cells to oxidative stress [357] (see Table 2).