ZEB2 facilitates peritoneal metastasis by regulating the invasiveness and tumorigenesis of cancer stem-like cells in high-grade serous ovarian cancers

Peritoneal metastasis is a common issue in the progression of high-grade serous ovarian cancers (HGSOCs), yet the underlying mechanism remains unconfirmed. We demonstrated that ZEB2, the transcription factor of epithelial-mesenchymal transition (EMT), was upregulated in ascites cells from HGSOC patients and in CD133(+) cancer stem-like cells (CSLCs) from epithelial ovarian cancer (EOC) cell lines. SiRNA-mediated knockdown of ZEB2 in EOC cells decreased the percentage of CSLCs and reduced the colony forming potential, cell invasion capacity and expression of pluripotent genes Oct4 and Nanog. Inhibition of ZEB2 also induced cellular apoptosis and impacted the tumorigenicity of ovarian CSLCs. The mesenchymal markers N-cadherin and vimentin were downregulated, while the epithelial marker E-cadherin was upregulated after ZEB2 knockdown. MiR-200a, a molecule that downregulates ZEB2, had the opposite effect of ZEB2 expression in EOC-CSLCs. A retrospective study of 98 HGSOC patients on the relationship of ascites volume, pelvic and abdominal metastasis, International Federation of Gynecology and Obstetrics (FIGO) stage and the malignant involvement of abdominal organs and lymph nodes was performed. Patients with high expression of ZEB2 in tumour tissues had a higher metastasis rate and a poorer prognosis than those with low expression. The parameters of ZEB2 expression and ascites volume were strongly linked with the prognostic outcome of HGSOC patients and had higher hazard ratios. These findings illustrated that ZEB2 facilitates the invasive metastasis of EOC-CSLCs and can predict peritoneal metastasis and a poor prognosis in HGSOC patients.