VAV1 inhibition: exploring drug design strategies for targeting gef activity

Abstract

[EN]VAV1 is a RHO guanine nucleotide exchange factor (GEF) predominantly expressed in hematopoietic cells, where it activates RHO GTPases —primarily RAC1—and plays essential roles in T cell development, immune response and cell signaling. Recent studies have elucidated VAV1’s involvement in various immune system pathologies and cancers, underscoring its therapeutic potential. Understanding the structure-activity relationship of VAV1 concerning its GEF-dependent and GEF-independent functions provides a foundation for developing specific VAV1 GEF inhibitors. In this thesis, we employed different drug design strategies to identify specific inhibitors of VAV1 GEF activity. We identified two pockets of interest within key regulatory domains of the protein that enabled to perform a virtual ligand screening of millions of compounds. From the hits obtained in this screening, we created a library of compounds designed based on two promising hits, introducing chemical modifications to improve initial VAV1 GEF inhibition. The activity of these compounds, asserted through VAV1—RAC1 nucleotide exchange assays, showed significant improvement following various chemical modifications. Further characterization of lead compounds was performed using biochemical and cellular assays to assess their specificity for VAV1 GEF inhibition. Additional strategies in this project included the design and synthesis of a stapled peptide targeting VAV1, as well as high-throughput screening of two large compound libraries. Overall, this thesis presents a comprehensive exploration of strategies for identifying and validating VAV1 GEF inhibitors, revealing promising candidates for further investigation