Identification of Phenazine‐Based MEMO1 Small‐Molecule Inhibitors: Virtual Screening, Fluorescence Polarization Validation, and Inhibition of Breast Cancer Migration

Phosphorylation‐dependent protein–protein interactions play a significant role in biological signaling pathways; therefore, small molecules that are capable of influencing these interactions can be valuable research tools and have potential as pharmaceutical agents. MEMO1 (mediator of ErbB2‐cell driven motility) is a phosphotyrosine‐binding protein that interacts with a variety of protein partners and has been found to be upregulated in breast cancer patients. Herein, we report the first small‐molecule inhibitors of MEMO1 interactions identified through a virtual screening platform and validated in a competitive fluorescence polarization assay. Initial structure–activity relationships have been investigated for these phenazine‐core inhibitors and the binding sites have been postulated using molecular dynamics simulations. The most potent biochemical inhibitor is capable of disrupting the large protein interface with a KI of 2.7 μm. In addition, the most promising phenazine core compounds slow the migration of breast cancer cell lines in a scratch assay. In breast cancer the phosphorylated‐tyrosine binding protein MEMO1 is upregulated. Herein, we report small‐molecule inhibitors of MEMO1 identified through virtual screening, validated with fluorescence polarization, and modeled in molecular dynamics simulations. These phenazine‐based compounds are capable of inhibiting breast cancer cell migration, will be useful probes of MEMO1 function, and have potential as therapeutic candidates.