The XPO1 Inhibitor Eltanexor Modulates the Wnt/β-Catenin Signaling Pathway to Reduce Colorectal Cancer Tumorigenesis.

Colorectal cancer is the second leading cause of cancer-related death in the United States and high-risk individuals face a notably higher likelihood of developing colorectal cancer based on their genetic background. Hence, there is a compelling need for innovative chemopreventive treatments aimed at minimizing colorectal cancer tumorigenesis. Exportin 1 (XPO1; also referred to as CRM1) plays a pivotal role in transporting proteins from the nucleus to the cytoplasm. Various cancers overexpress XPO1, including colorectal cancer, and selective inhibitors of nuclear export compounds, such as eltanexor (KPT-8602), have been developed to target XPO1. Eltanexor demonstrates fewer adverse effects than its precursors and is currently under evaluation in phase I/II clinical trials. This research evaluates eltanexor as a chemopreventive agent for colorectal cancer. Our findings indicate that eltanexor treatment inhibits expression of the common chemoprevention target in colorectal cancer, COX-2. This occurs by eltanexor-dependent reduction of Wnt/β-catenin signaling. Furthermore, XPO1 inhibition leads to forkhead transcription factor O subfamily member 3a nuclear retention, which can modulate β-catenin/TCF transcriptional activity. The in vivo oral treatment of eltanexor to Apcmin/+ mice (a mouse model for familial adenomatosis polyposis) was well tolerated and reduced tumor burden by approximately threefold, along with decreased tumor size. Drug sensitivity assays using organoids from Apcmin/+ mice tumors showed increased sensitivity to eltanexor compared with wild-type organoids. Collectively, these findings highlight XPO1 as a potent target for colorectal cancer chemoprevention.

Significance: In this study, we show the XPO1 inhibitor eltanexor acts as an effective colorectal cancer chemopreventive agent both in vivo and in vitro. This occurs by reducing COX-2 expression by modulating the Wnt/β-catenin signaling pathway. Collectively, these findings highlight XPO1 as a potent target for colorectal cancer chemoprevention.