MiR-203 is downregulated in laryngeal squamous cell carcinoma and can suppress proliferation and induce apoptosis of tumours

MicroRNAs (miRNAs) have been recognised to regulate cancer development and progression in carcinogenesis as either oncogenes or tumour suppressor genes. However, whether miR-203 plays a crucial role in human laryngeal squamous cell carcinoma (LSCC) remains largely unclear. In the study, we have found that miR-203 expression was significantly lower in LSCC tissues than that in corresponding adjacent non-neoplastic tissues and was negatively correlated with ASAP1 expression level. Lower expression of miR-203 was significantly related to poor differentiation, advanced clinical stages, T3–4 tumour grade, lymph node metastasis and decreased 5-year overall survival. Transfection with miR-203 inhibited proliferation, reduced invasion, induced apoptosis and caused G1 phase cell cycle arrest of Hep-2 cells in vitro, suggesting that miR-203 functioned as a tumour suppressor. We have also tested that over-expression of miR-203 may both suppress the growth of xenograft tumours in mice and downregulate the expressions of ASAP1 in vivo. Furthermore, miR-203 may regulate the expressions of mesenchymal transition (EMT) marker of E-cadherin and cancer stem cells (CSCs) marker of CD44. These findings suggest that miR-203 plays a role as a tumour suppressor in LSCC, likely by regulating ASAP1, probably in relation to EMT and CSCs and may serve as a potential target for therapeutic intervention.