Pluripotency transcription factor Nanog and its association with overall oral squamous cell carcinoma progression, cisplatin-resistance, invasion and stemness acquisition.

BACKGROUND Cisplatin-resistant oral squamous cell carcinoma (OSCC) cells acquire stem-like characteristics and are difficult to treat. Nanog is a transcription factor and needed for maintenance of pluripotency, but its transcription-promoting role in OSCC progression and cisplatin resistance is poorly understood. METHODS Here, 110 fresh human tissue specimens of various stages, including invasive (N1-3 )/chemoradiation-resistant OSCC samples, cisplatin-resistant (CisR-SCC-4/-9) OSCC cells/parental cells, photochemical ECGC, and siRNA (Nanog) were used. RESULTS Nanog overexpression was associated with overall progression, chemoresistance, and invasion of OSCC. Nanog recruitment to c-Myc, Slug, E-cadherin, and Oct-4 gene promoter was observed. Positive correlation of Nanog protein expression with c-Myc, Slug, cyclin D1, MMP-2/-9, and Oct-4 and negative correlation with E-cadherin gene expression were found. Knockdown of Nanog and treatment of epicatechin-3-gallate reversed cisplatin resistance and diminished invasion/migration potential. CONCLUSION Nanog directly participated in the regulation of Slug, E-cadherin, Oct-4, and c-Myc genes, causing cisplatin resistance/recurrence of OSCC.