Snail and Slug collaborate on EMT and tumor metastasis through miR-101-mediated EZH2 axis in oral tongue squamous cell carcinoma

While the roles of Snail and Slug as individual EMT-inducing transcription factors are well-documented, the mechanisms by which they coordinate to drive metastasis in oral tongue squamous cell carcinoma (OTSCC) remain poorly understood. This study investigates the interplay between these factors and their potential to regulate microRNAs (miRNAs) to promote malignant progression.

The researchers performed immunohistochemical staining on 89 human OTSCC samples to correlate Snail and Slug expression with clinical outcomes. Using OTSCC cell lines (Cal-27 and Tca8113), they employed short hairpin RNA (shRNA) knockdown and overexpression experiments to assess the impact of these proteins on cell migration, invasion, and EMT markers. A miRNA microarray was used to identify miRNAs regulated by Snail and Slug, followed by functional assays to determine how the identified miRNA (miR-101) interacts with the downstream target EZH2.

The study found that the co-overexpression of Snail and Slug is an independent prognostic factor for poor survival in OTSCC patients. In vitro, these factors synergistically promote an EMT phenotype, characterized by increased cell migration, invasion, and the acquisition of stem cell-like properties (e.g., increased CD133+/CD44+ populations). The researchers identified miR-101 as a tumor-suppressive miRNA that is directly repressed by both Snail and Slug. The subsequent loss of miR-101 leads to the activation of EZH2, a histone methyltransferase that drives the EMT program. This establishes a novel Snail/Slug-miR-101-EZH2 regulatory axis that facilitates tumor progression.

This research provides a mechanistic link between classic EMT transcription factors and epigenetic regulation via miRNAs. By identifying the Snail/Slug-miR-101-EZH2 pathway, the study highlights a potential therapeutic target for preventing metastasis in OTSCC, suggesting that restoring miR-101 or inhibiting EZH2 could mitigate the aggressive behaviors induced by Snail and Slug.