Discovery of Potent Covalent CRM1 Inhibitors Via a Customized Structure-Based Virtual Screening Pipeline and Bioassays

CRM1 (chromosomal region maintenance 1, also referred
to as exportin
1 or XPO1) plays a crucial role in maintaining the appropriate nuclear
levels of tumor suppressor proteins (TSPs), growth regulatory proteins
(GRPs), and antiapoptotic proteins, thereby contributing significantly
to their anticancer effects. Dysregulation of CRM1-mediated nuclear
transport, observed in a range of cancers such as colon cancer as
well as autoimmune diseases, highlights its significance in various
disease processes. In this paper, we employed a customized structure-based
virtual screening campaign to search for novel covalent CRM1 inhibitors
and purchased 50 potentially active compounds for in vitro bioassays.
Among these candidates, AN-988 displayed a notably higher binding
affinity (KD = 615 nM) toward CRM1, as
determined by the biolayer interferometry (BLI) assay. Furthermore,
AN-988 exhibited a strong suppression of colorectal cancer cell proliferation
and remarkable anti-inflammatory effects. Notably, AN-988 induced
cell apoptosis and cell cycle arrest in a time- and dose-dependent
manner by effectively inhibiting the translocation of FOXO3a from
the nucleus to the cytosol, thereby preserving the activity of FOXO3a.
Collectively, our study identified AN-988 as a promising CRM1 inhibitor,
underscoring its potential as a preclinical colon cancer therapy candidate.