title: MiR-497 enhances metastasis of oral squamous cell carcinoma through SMAD7 suppression.
abstract: SMAD7 is a key inhibitor of transforming growth factor β (TGFβ) receptor signaling, which regulates the alteration of cancer cell invasiveness through epithelial-mesenchymal cell conversion. Since microRNAs (miRNAs) play a potential role in the tumorigenesis, cancer cell growth and metastases of oral squamous cell carcinoma (OSCC), determination of the involved miRNAs that may regulate SMAD7-mediated OSCC cell invasion appears to be one important question. Here, we found that the levels of miR-497 were significantly increased and the levels of SMAD7 were significantly decreased in OSCC specimens, compared to the paired adjacent non-tumor tissue. Moreover, miR-497 and SMAD7 inversely correlated in OSCC specimens. The 5-year survival of the patients with higher miR-497 levels in the resected OSCC was worse than those high miR-497 levels. Bioinformatics analyses showed that miR-497 targeted the 3'-UTR of SMAD7 mRNA to inhibit its translation, which was proved by luciferase reporter assay. Furthermore, miR-497 overexpression increased SMAD7-suppressed cell invasion, while miR-497 depletion decreased SMAD7-suppressed cell invasion in OSCC cells, in both a transwell cell invasion assay and a scratch would healing assay. Together, our data suggest that suppression of miR-497 in OSCC cells may promote cancer cell invasion via suppression of SMAD7, and highlight miR-497 as an intriguing therapeutic target to prevent OSCC metastases.
authors: Department of Prosthodontics, Hospital of Stomatology Affiliated to Zhejiang University Hangzhou 310006, China.
authors: Jun
authors: J
authors: Hu
authors: Department of Stomatology, Tongde Hospital of Zhejiang Province Hangzhou 310012, China.
authors: Jun-Feng
authors: JF
authors: Xu
authors: Department of Maxillofacial Surgery, Hospital of Stomatology Affiliated to Zhejiang University Hangzhou 310006, China.
authors: Wei-Li
authors: WL
authors: Ge
keywords: Aral squamous cell carcinoma (OSCC); SMAD7; cancer cell invasion; miR-497