Long non-coding RNA maternally expressed gene 3 inhibits osteogenic differentiation of human dental pulp stem cells via microRNA-543/smad ubiquitin regulatory factor 1/runt-related transcription factor 2 axis.

OBJECTIVE: The aim of the present study was to investigate the biological roles and underlying mechanism of the long non-coding RNA maternally expressed gene 3 (MEG3) on osteogenic differentiation of human dental pulp stem cells (hDPSCs). METHODS: The expression levels of MEG3, microRNA-543 (miR-543), osterix, osteopontin, osteocalcin and runt-related transcription factor 2 (RUNX2) were measured by quantitative real-time PCR (qRT-PCR). Alkaline phosphatase (ALP) activity assay and alizarin red S staining (ARS) were used to measure the impacts exerted by MEG3, miR-543 on osteogenic differentiation. Cell proliferation was measured by MTT assay. In addition, the targeted relationships between miR-543, MEG3, and Smad ubiquitin regulatory factor 1 (SMURF1) were assessed through dual luciferase reporter assay. RESULTS: During osteogenic induction, the expression of MEG3 was gradually reduced, whereas the expression of miR-543, osterix, osteopontin, osteocalcin and RUNX2 were gradually increased. Functional analysis implied that MEG3 overexpression or miR-543 inhibition reduced the cell proliferation, ALP activity, ARS levels, and decreased the expression of osteoblast-related proteins. Moreover, MEG3 promoted SMURF1 expression by directly targeting miR-543 as a competing endogenous RNA. Furthermore, overexpression of miR-543 or silencing SMURF1 could reverse the inhibitory effects of MEG3 on the osteogenic differentiation of hDPSCs. CONCLUSIONS: In conclusion, our study revealed that overexpression of MEG3 inhibited hDPSCs osteogenic differentiation via miR-543/SMURF1/RUNX2 regulatory network, which may contribute to the functional regulation and clinical applications of hDPSCs.

High ACTN1 Is Associated with Poor Prognosis, and ACTN1 Silencing Suppresses Cell Proliferation and Metastasis in Oral Squamous Cell Carcinoma.

PURPOSE: Oral squamous cell carcinoma (OSCC) is a common malignancy of the oral cavity. As the survival rate of OSCC patients is low, it is crucial to explore new markers and therapeutic targets for early diagnosis of the disease. A high level of actinin alpha 1 (ACTN1) in patients could serve as an independent prognostic factor of acute myeloid leukemia. However, the role of ACTN1 in OSCC remains unclear. In the present study, we aimed to investigate the role of ACTN1 in OSCC. METHODS: ACTN1 protein levels in tissues were determined by immunohistochemical (IHC) staining. The correlation of ACTN1 expression with clinicopathological features and prognosis was analyzed. Univariate and multivariate analyses were performed. The effect of ACTN1 knockdown on cell proliferation, migration, invasion, apoptosis, epithelial-mesenchymal transition (EMT), and the cell cycle was evaluated using Western blotting, Cell Counting Kit­8 (CCK8) assays, flow cytometry analysis, transwell assays, wound-healing assays, and nude mouse models of subcutaneous xenograft and pulmonary metastasis. RESULTS: Based on the total score of ACTN1 IHC staining analysis, ACTN1 expression was found to be low in 10 normal mucosal tissues, 48 normal mucosal tissues adjacent to OSCC, and 19 OSCC tissues, but high in 29 OSCC tissues. ACTN1 protein levels were significantly associated with the clinical stage and node metastasis, and a high ACTN1 protein level indicated poor prognosis. Moreover, ACTN1 expression was an independent predictor of poor prognosis of OSCC. Using in vitro assays, we found that ACTN1 knockdown could induce cell cycle arrest, promote apoptosis, and inhibit EMT and cell proliferation, migration, and invasion in the OSCC cell lines, SCC-15 and HSC-3. Moreover, ACTN1 knockdown inhibited subcutaneous tumor growth and pulmonary metastasis in vivo. CONCLUSION: ACTN1 levels were significantly associated with the clinical stage and node metastasis, and a high ACTN1 protein level indicated poor prognosis. Moreover, ACTN1 knockdown could suppress cell proliferation and metastasis of OSCC. Our results suggested that ACTN1 may serve as a diagnostic and prognostic marker of OSCC.