Sulfasalazine Induces Ferroptosis Of Breast Cancer Cells And Its Mechanism

Objective:To clarify the activation of ferroptosis in different breast cancer cells by sulfasalazine(SAS)and to explore the relationship between estrogen receptor(ER)and transferrin receptor(TFRC).Method: SAS were used to treat MDA-MB-231 and T47 D for 24 h.Observing changes in cell morphology under a microscope;CCK-8detected the the proliferation inhibition rate.Western blot was used to detect the expression of glutathione peroxidase 4(GPX4)and xCT;Flow cytometry to indicate changes in the production of reactive oxygen species(ROS);Observation of mitochondrial morphological changes in T47 D by transmission electron microscopy.Confocal fluorescence microscopy was used to observe the changes of mitochondrial membrane potential(MMP).RT-PCR detection of mRNA expression levels of TFRC and divalent metal transporter 1(DMT1);Bioinformatics analysis of the expression of TFRC in 1208 breast cancer samples and its relationship with ER.Immunohistochemistry detected the TFRC expression in different tissues.Small interfering RNA(siRNA)knocked down the expression of ER in T47 D,and observed mRNA and protein changes of TFRC;RT-PCR wasused to detect the expression of TFRC in 87 clinical specimens.Result: SAS could inhibit the viability of breast cancer cells,which was accompanied by an abnormal increase in ROS and a depletion of GPX4 and system xc-.Liproxstatin-1 reversed the SAS-induced increase in ROS.The cells treated with SAS had shrunken mitochondria and decreased MMP.SAS upregulated TFRC and DMT1.Knockdown of ER increased the expression of TFRC in breast cancer cells.Immunohistochemistry showed that TFRC expression was lower in ER(+)breast cancer than in ER(-)breast cancer tissue.After verifying with RT-PCR in 87 clinical specimens,the expression of TFRC in ER(-)tissue was significantly higher than that of ER(+).Conclusion: SAS can trigger ferroptosis in breast cancer cells,especially cells with low ER expression.Therefore,SAS is a potential agent for breast cancer treatment.