miR-1 as a tumor suppressive microRNA targeting TAGLN2 in head and neck squamous cell carcinoma

Based on the microRNA (miRNA) expression signatures of hypopharyngeal and esophageal squamous cell carcinoma, we found that miR-1 was significantly down-regulated in cancer cells. In this study, we investigated the functional significance of miR-1 in head and neck squamous cell carcinoma (HNSCC) cells and identified miR-1-regulated novel cancer pathways. Gain-of-function studies using miR-1 revealed significant decreases in HNSCC cell proliferation, invasion, and migration. In addition, the promotion of cell apoptosis and cell cycle arrest was demonstrated following miR-1e transfection of cancer cells. A search for the targets of miR-1 revealed that transgelin 2 (TAGLN2) was directly regulated by miR-1. Silencing of TAGLN2 significantly inhibited cell proliferation and invasion in HNSCC cells. Down-regulation of miR-1 and up-regulation of TAGLN2 were confirmed in HNSCC clinical specimens. Our data indicate that TAGLN2 may have an oncogenic function and may be regulated by miR-1, a tumor suppressive miRNA in HNSCC. The identification of novel miR-1-regulated cancer pathways could provide new insights into potential molecular mechanisms of HNSCC carcinogenesis.