Py2T C40 and Py2T I60 cells, long-term treated murine derived breast cancer cell lines with H2O2

Background: Epithelial-mesenchymal transition (EMT) has been implicated in metastasis, drug resistance, survival under stress and also conferring stem cell-like traits to cancer cells. We have aimed at exploring the crosstalk between ROS and an EMT induced by TGFb in breast cancer cells. Methods: We observed that cells exposed to TGFb displayed a decrease of ROS levels. To identify the antioxidant pathways activated during EMT, we investigated the effect of long-term oxidative stress, for example by H2O2 (40 µM and 60 µM), on Py2T epithelial cells derived from the MMTV-PyMT mouse model. Results: We show that long-term treated Py2T epithelical cells with H2O2 display both higher migratory capability and tumorigenicity. Furthermore, we identified an activation of the Nrf2 transcription factor, master regulator of the antioxidant response, in H2O2-resistant cells, as well as in TGFb-induced mesenchymal cells. Conclusion: In this study we report the criticial role of the Nrf2-mediated glutathione metabolism in the protection of metastatic breast cancer cells from ferroptosis. Therapeutic targeting of antioxidant pathways may thus be beneficial for patients with metastatic disease. Overall design: RNA-Seq of H2O2 Py2T cells (Py2T C40 and Py2T I60) performed in biological duplicates