EZH2 as regulator of stemness signature and driver of esophageal squamous cell carcinomas.

Esophageal squamous cell carcinoma (ESCC) is the sixth leading cause of cancer-related death globally. Current therapies remain inadequate, largely due to the persistence of stem-like residual tumor cells. The role of EZH2 as a cancer stem cell (CSC) regulator in tumor development has not been fully elucidated. We investigated EZH2 expression and its association with CSC markers in ESCC patients using bioinformatics analyses and gene expression assays. Functional analyses were used to assess the role of EZH2 in self-renewal, proliferation, migration, invasion, and chemotherapy resistance. Xenograft models were used to evaluate EZH2 impact on tumor growth, pulmonary metastasis, and angiogenesis in vivo. Additional techniques, including apoptosis assays, qRT-PCR, ICC, and IHC, were used to explore the mechanisms underlying EZH2 effects on stemness properties. EZH2 enhanced stemness and self-renewal in ESCC by upregulating stemness‑associated markers, resulting in increased colony and sphere formation in vitro. It promoted ESCC proliferation by facilitating the G1-to-S transition and upregulating CD markers involved in CSC maintenance. EZH2 also reduced apoptosis and increased cell viability. Additionally, EZH2 increased resistance to 5-fluorouracil and Cisplatin. In vivo studies demonstrated that EZH2 overexpression accelerated tumor growth, metastasis, and angiogenesis. Targeting EZH2 with specific inhibitors significantly suppressed tumor progression and improved survival in ESCC xenograft models. Our molecular docking analysis suggests a PRC2-independent (non-canonical) potential of EZH2 association with stemness regulators (NANOG, OCT4, and SOX2). This findings suggest EZH2 as a potential target for developing novel neoadjuvant therapy strategies in ESCC.