CELF6 as an Oncogene in Colorectal Cancer: Targeting Stem-Cell-Like Properties Through Modulation of HOXA5 mRNA Stability

Background: Emerging evidence indicates the essential role of cancer stem cells (CSCs) in the development and progression of various cancers, including colorectal cancer (CRC). CELF6, a member of the cytosine-uridine-guanine-binding protein (CUG-BP), Elav-like family (CELF), has been reported to be downregulated in CRC tissues. This study aims to elucidate the role and underlying mechanisms of CELF6 in CRC progression. Methods: The expression levels and prognostic significance of CELF6, along with its association with homeobox A5 (HOXA5), were analyzed using University of Alabama at Birmingham Cancer Data Analysis Portal (UALCAN), PrognoScan, and Tumor Immune Estimation Resource (TIMER) databases. The expression of CELF6 was further assessed through quantitative real-time polymerase chain reaction (qRT-PCR), immunoblotting, and immunohistochemistry. Both in vitro and in vivo experiments were conducted to investigate the effects of CELF6 on CRC cell proliferation, stemness and tumorigenesis, and to elucidate the molecular mechanisms. Results: CELF6 was found to be downregulated in CRC and was associated with poor prognosis. Functional studies revealed that overexpression of CELF6 resulted in decreased CRC cell proliferation and stemness in vitro, reduced tumor growth in vivo, and induced G1 phase cell cycle arrest. Mechanistically, CELF6 regulated the expression of HOXA5 by modulating its mRNA stability. Furthermore, the knockdown of HOXA5 reversed the inhibitory effects of CELF6 on CRC cell proliferation and stemness, demonstrating that silencing HOXA5 counteracted the suppressive effects of CELF6. Conclusions: This study is the first to identify CELF6 as a suppressor of stemness and a modulator of CRC progression. These findings provide new insights into the role of CELF6 in CRC and highlight its potential as a novel therapeutic target.