MicroRNAs (miRNAs) are reported to function as a major component in the cellular signaling circuit, which regulates epithelial-mesenchymal transition (EMT). Dysregulation of the microRNA-200 (miR-200) family and EMT-associated genes enables tumor metastasis and resistance to therapy. The present study profiled miR-200 family members miR-200a, miR-200b, miR-200c, miR-141 and miR-429, and also several EMT-regulatory genes including zinc finger E-box-binding homeobox (ZEB)1, ZEB2, epithelial cadherin and vimentin in 40 oral primary tumors in order to understand their role(s) in oral squamous cell carcinoma (OSCC). The reverse transcription-quantitative polymerase chain reaction was used to analyze each sample. Results demonstrated a significant downregulation of miR-200 family members in tumors with a history of tobacco chewing/smoking (P<0.0006, P=0.0467, P=0.0014, P=0.0087 and P=0.0230, respectively) and undifferentiated pathology (miR-200a, P=0.0067; miR-200c, P=0.0248). EMT markers ZEB2 (P=0.0451) and vimentin (P=0.0071) were significantly upregulated in the oral tumors. Furthermore, ZEB2 antisense RNA1 was overexpressed in 50% of OSCC samples (P=0.0075). EMT-regulatory genes did not exhibit any association with clinical outcome. The present study also analyzed the expression of EMT-regulatory genes in 523 head and neck squamous cell carcinoma (HNSCC) samples from The Cancer Genome Atlas (TCGA) database, and the association with treatment outcome. Analysis of TCGA datasets also demonstrated no significant association in the expression of EMT markers with disease recurrence and treatment outcome. The results of the present study revealed dysregulation of miR-200 family miRNAs and EMT-regulatory genes in OSCC without any significant effect on treatment outcome.
Keywords: epithelial-mesenchymal transition; microRNA-200 family; non-coding RNA; oral cancer; zinc finger E-box-binding homeobox 2 antisense RNA1.