Identification of HMGA2 inhibitors by AlphaScreen-based ultra-high-throughput screening assays
Linjia Su, Nadezda Bryan, Sabrina Battista, Juliano T. Freitas, Alyssa Garabedian, Federica D’Alessio, Miriam Romano, Fabiana Falanga, Alfredo Fusco, Lidia Kos, Jeremy W. Chambers, Francisco Fernandez‐Lima, Prem P. Chapagain, Stefan Vasile, Layton H. Smith, Fenfei Leng
Abstract
The mammalian high mobility group protein AT-hook 2 (HMGA2) is a multi-functional DNA-binding protein that plays important roles in tumorigenesis and adipogenesis. Previous results showed that HMGA2 is a potential therapeutic target of anticancer and anti-obesity drugs by inhibiting its DNA-binding activities. Here we report the development of a miniaturized, automated AlphaScreen ultra-high-throughput screening assay to identify inhibitors targeting HMGA2-DNA interactions. After screening the LOPAC1280 compound library, we identified several compounds that strongly inhibit HMGA2-DNA interactions including suramin, a century-old, negatively charged antiparasitic drug. Our results show that the inhibition is likely through suramin binding to the "AT-hook" DNA-binding motifs and therefore preventing HMGA2 from binding to the minor groove of AT-rich DNA sequences. Since HMGA1 proteins also carry multiple "AT-hook" DNA-binding motifs, suramin is expected to inhibit HMGA1-DNA interactions as well. Biochemical and biophysical studies show that charge-charge interactions and hydrogen bonding between the suramin sulfonated groups and Arg/Lys residues play critical roles in the binding of suramin to the "AT-hook" DNA-binding motifs. Furthermore, our results suggest that HMGA2 may be one of suramin's cellular targets.