HUWE1 loss promotes stemness and drug resistance in CRC with dysregulated β-catenin destruction complex.

Cancer stem cells (CSCs) are a key driver of tumor initiation, progression, and drug resistance in colorectal cancer (CRC). The Wnt/β-catenin signaling pathway, which is hyperactivated in nearly all CRC cases, plays a crucial role in CSC-related processes such as proliferation, epithelial-mesenchymal transition (EMT), and metastasis. In this study, we demonstrate that HUWE1 plays a critical regulator of Wnt/β-catenin signaling, similar to the β-catenin destruction complex. Under conditions of β-catenin destruction complex inactivation, most HUWE1 directly interacts with and ubiquitinates β-catenin. Conversely, when the destruction complex is active, HUWE1 targets upstream proteins for ubiquitination, thereby regulating Wnt/β-catenin signaling. This highlights HUWE1 as a pivotal regulator of Wnt/β-catenin signaling, particularly in CRC cases characterized by frequent APC mutations. Our findings further show that HUWE1 loss in CRC cells stabilizes β-catenin, enhancing CSC traits and promoting EMT. Additionally, HUWE1 depletion leads to excessive mitochondrial biogenesis, which contributes to drug resistance by supplying significant ATP levels to ATP-binding cassette (ABC) transporters. In conclusion, this study uncovers a previously unrecognized role of HUWE1 in regulating Wnt/β-catenin signaling and its impact on CRC. These insights may aid in identifying colorectal CSCs and developing targeted therapeutic strategies.