TY - JOUR A1 - Nishida Xavier da Silva, Thamara A1 - Schulte, Clemens A1 - Nunes Alves, Ariane A1 - Maric, Hans Michael A1 - Friedmann Angeli, José Pedro T1 - Molecular characterization of AIFM2/FSP1 inhibition by iFSP1-like molecules JF - Cell Death & Disease N2 - Ferroptosis is a form of cell death characterized by phospholipid peroxidation, where numerous studies have suggested that the induction of ferroptosis is a therapeutic strategy to target therapy refractory cancer entities. Ferroptosis suppressor protein 1 (FSP1), an NAD(P)H-ubiquinone reductase, is a key determinant of ferroptosis vulnerability, and its pharmacological inhibition was shown to strongly sensitize cancer cells to ferroptosis. A first generation of FSP1 inhibitors, exemplified by the small molecule iFSP1, has been reported; however, the molecular mechanisms underlying inhibition have not been characterized in detail. In this study, we explore the species-specific inhibition of iFSP1 on the human isoform to gain insights into its mechanism of action. Using a combination of cellular, biochemical, and computational methods, we establish a critical contribution of a species-specific aromatic architecture that is essential for target engagement. The results described here provide valuable insights for the rational development of second-generation FSP1 inhibitors combined with a tracer for screening the druggable pocket. In addition, we pose a cautionary notice for using iFSP1 in animal models, specifically murine models. KW - cell biology KW - chemical libraries Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357943 VL - 14 ER - TY - JOUR A1 - Lorenzin, Francesca A1 - Benary, Uwe A1 - Baluapuri, Apoorva A1 - Walz, Susanne A1 - Jung, Lisa Anna A1 - von Eyss, Björn A1 - Kisker, Caroline A1 - Wolf, Jana A1 - Eilers, Martin A1 - Wolf, Elmar T1 - Different promoter affinities account for specificity in MYC-dependent gene regulation JF - eLife N2 - Enhanced expression of the MYC transcription factor is observed in the majority of tumors. Two seemingly conflicting models have been proposed for its function: one proposes that MYC enhances expression of all genes, while the other model suggests gene-specific regulation. Here, we have explored the hypothesis that specific gene expression profiles arise since promoters differ in affinity for MYC and high-affinity promoters are fully occupied by physiological levels of MYC. We determined cellular MYC levels and used RNA- and ChIP-sequencing to correlate promoter occupancy with gene expression at different concentrations of MYC. Mathematical modeling showed that binding affinities for interactions of MYC with DNA and with core promoter-bound factors, such as WDR5, are sufficient to explain promoter occupancies observed in vivo. Importantly, promoter affinity stratifies different biological processes that are regulated by MYC, explaining why tumor-specific MYC levels induce specific gene expression programs and alter defined biological properties of cells. KW - MYC KW - promoter affinity KW - human KW - mathematical modeling KW - mouse KW - ChIP-sequencing KW - MIZ1 KW - cancer biology KW - cell biology KW - WDR5 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-162913 VL - 5 ER -