Implication of Epigenetic Alterations of ZEB1 in Colorectal Cancer (CRC) Pathogenesis and Therapy Development

Colorectal cancer (CRC) is a significant cause of cancer mortality in the world, and its etiology is complicated by genetic and epigenetic changes. As one of the most important tumor progression regulators, Zinc Finger E-box Binding Homeobox 1 (ZEB1) is a transcription factor that has a key role in epithelial-mesenchymal transition (EMT), which is essential in the metastasis, drug resistance, and plasticity of cancer cells in CRC. ZEB1 silences the expression of epithelial markers, including E-cadherin, and it induces the development of mesenchymal properties, such as invasion and metastasis, i.e., tumor aggressiveness. ZEB1 drives epigenetic reprogramming in CRC by coordinating histone deacetylation, histone methylation, and DNA methylation of epithelial tumor suppressor gene promoters and by engaging in reciprocal regulatory interactions with non-coding RNAs, including the miR-200 family. Furthermore, multiple oncogenic signaling cascades, including Wnt/β-catenin, TGF-β, NF-κB, MEK-ERK, JAK/STAT3, and HIF-1α, converge on ZEB1 to amplify its transcriptional and epigenetic activity, positioning ZEB1 as a nodal integrator of extracellular cues and epigenetic reprogramming in CRC metastasis. This review integrates three interconnected regulatory layers, i.e., (1) ZEB1's direct epigenetic control of target gene expression via histone modification and DNA methylation, (2) post-transcriptional regulation of ZEB1 itself by ncRNAs (miRNAs, circRNAs, and lncRNAs) that create feedback circuits modulating layer 1, and (3) upstream modulation of ZEB1 transcriptional activity by oncogenic signaling pathways (Wnt/β-catenin, TGF-β, NF-κB, MEK-ERK, JAK/STAT3, and HIF-1α) to provide a comprehensive picture of ZEB1 in CRC metastasis and its therapeutic implications.