Browsing by Author "Mudrovcic, Korana"

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Data for "Early-stage autophagy inhibitors targeting the ATG101-ATG13 subunit of the ULK1 complex"
(2025) Mudrovcic, Korana; Gopalswamy, Mohanraj; Gohlke, Holger
Autophagy is commonly up- or down-regulated in cancer cells due to the unique metabolic needs of these cells, and small molecules modulating the autophagy pathway are already in clinical trials. However, specific autophagy-targeting compounds remain rare. A new potential mechanism for effective early-stage autophagy inhibition was described by us and others recently, involving the inhibition of the interaction between ATG101 and ATG13 subunits of the autophagy-initiating ULK1 complex. Here, we describe the discovery of two small molecules inhibiting the ATG101-ATG13 interaction, one by binding to ATG101 with micromolar affinity (EC50 = 151 µM) and the other by binding to both ATG101 and ATG13 with micromolar affinity (EC50 = 135 µM and EC50 = 107 µM, respectively). In two independent assays, both compounds inhibit autophagy. Scrutinizing the binding mechanism by molecular dynamics simulations and STD-NMR spectroscopy indicates that the compounds bind to ATG101 in an orthosteric fashion, at the interface of the protein-protein interaction, while the binding to ATG13 is allosteric. Both compounds have a favorable predicted ADME-Tox profile. The compounds can serve as tool compounds to inhibit autophagy or as candidates for further optimization toward lead structures.
Data for "Identification of autophagy inhibitors selectively targeting the ATG13-ATG101 protein-protein interaction"
(2025) Mudrovcic, Korana; Gopalswamy, Mohanraj; Gohlke, Holger
The dysregulation of autophagy promotes the development of several diseases like such as neurodegeneration, infection, or cancer. To keep up with their metabolic demand under low nutrient and/or oxygen conditions typically present in the tumor microenvironment, cancer cells can upregulate autophagy autonomously or in surrounding cells. Therefore, the inhibition of autophagy is desired in these settings. However, to date, drugs targeting autophagy selectively remain rare. The autophagy-inducing ULK1 complex comprises ULK1/2, FIP200, and a heterodimer consisting of ATG13 and ATG101. We previously showed that the ATG13-ATG101 protein-protein interaction is crucial for the assembly of the ULK1 complex and initiation of autophagic activity. Thus, targeting the ATG13-ATG101 protein-protein interaction with small molecules promises to yield new tools for the study of autophagy as well as to deliver new therapeutic starting points. By screening a diversity set of 15k compounds in a biochemical setup, followed by extensive cell-based validation studies, we identified the compounds AFS30 and AFS32. Both compounds inhibited the ATG13-ATG101 PPI in the low micromolar range and led to reduced autophagic activity in different cell lines, with IC50 values of 3-4 µM in the LC3 HiBiT reporter assay. Spectral shift assays, molecular dynamics simulations, and STD-NMR suggested that the compounds bind allosterically to ATG13. AFS30 and AFS32 also promoted apoptosis in different cancer cell lines exposed to nutrient stress. We propose that AFS30 and AFS32 are promising lead compounds for the development of PPI inhibitors that selectively inhibiting the ATG13-ATG101 interaction and thus autophagy.