New pyrrole derivatives as ferroptosis inducers

Ferroptosis is an iron-dependent cell death which is different from apoptosis, necrosis, autophagy, and other forms of cell death. We synthesized new aroyl diheterocyclic pyrroles (ARDHEPs) as tubulin polymerization inhibitors. Among these compounds, the derivative (4-(furan-2-yl)-1-(pyrimidin-2-yl)-1H-pyrrol-3-yl)(3,4,5-trimethoxyphenyl)methanone (1) exhibited the hallmarks of ferroptosis. The new compound strongly inhibited U-87 MG, OVCAR-3, and MCF-7 cancer cells and induced an increase in cleaved PARP but was not toxic to normal human primary T lymphocytes at 0.1 M concentration. Analysis of the levels of lactoperoxidase, malondialdehyde, lactic acid, total glutathione, and ATP suggested that the in vivo inhibition of cancer cell proliferation by the new compound occurred through the stimulation of oxidative stress injury and Fe2+ accumulation. Quantitative polymerase chain reaction analysis of mRNA expression in U-87 MG and SKOV-3 tumor tissues from new ARDHEP-treated mice showed the presence of Ptgs2/Nfe2l2/Sat1/Akr1c1/Gpx4 genes correlated with ferroptosis in both groups. Immunofluorescence staining revealed significantly lower expressions of proteins Ki67, CD31, and ferroptosis-negative regulation proteins glutathione peroxidase 4 (GPX4) and FTH1. Finally, the new ARDHEP was found to be metabolically stable when incubated with human liver microsomes.