Reciprocal regulation of miR-1254 and c-Myc in oral squamous cell carcinoma suppresses EMT-mediated metastasis and tumor-initiating properties through MAPK signaling.

AIM: This study aimed to determine the effect of miR-1254 on oral squamous cell carcinoma (OSCC) metastasis and the specific mechanism involved. METHODS: The metastatic properties of OSCC cells were analyzed by transwell assays. The tumor-initiating properties of OSCC cells were analyzed by tumor sphere formation assays. The mRNA and protein expressions of targeted genes were determined by quantitative polymerase chain reaction assays and western blot analyses, respectively. Xenograft experiments were employed to evaluate the anti-metastatic effects of miR-1254 and miR-1254-mediated cancer stem cell (CSC) properties in vivo. The gene targets of miR-1254 were investigated by luciferase reporter assays. Chromatin immunoprecipitation assays were performed to observe the transcriptional regulation of miR-1254 biogenesis by transcription factor. RESULTS: miR-1254 attenuated OSCC metastasis and tumor-initiating properties in vitro and in vivo. Consistent with the experimental observations, miR-1254 was decreased in late-stage OSCCs and strongly correlated with risk of OSCC metastasis. Moreover, miR-1254 was mechanistically shown to down-regulate MAP3K3, accompanied by inactivation of the MAPK signaling pathway and inhibition of epithelial-mesenchymal transition (EMT) in OSCC cells. miR-1254 was transcriptionally repressed by c-Myc to form a positive feed back loop through MAPK signaling. CONCLUSION: Our findings suggest that miR-1254 is a potential target for the treatment of OSCCs, and miR-1254 can be clinically utilized as a biomarker for the clinical prognosis or diagnosis of OSCCs.

Beta-nerve growth factor promotes neurogenesis and angiogenesis during the repair of bone defects.

We previously showed that the repair of bone defects is regulated by neural and vascular signals. In the present study, we examined the effect of topically applied ß-nerve growth factor (ß-NGF) on neurogenesis and angiogenesis in critical-sized bone defects filled with collagen bone substitute. We created two symmetrical defects, 2.5 mm in diameter, on either side of the parietal bone of the skull, and filled them with bone substitute. Subcutaneously implanted osmotic pumps were used to infuse 10 µg ß-NGF in PBS (ß-NGF + PBS) into the right-hand side defect, and PBS into the left (control) defect, over the 7 days following surgery. Immunohistochemical staining and hematoxylin-eosin staining were carried out at 3, 7, 14, 21 and 28 days postoperatively. On day 7, expression of ß III-tubulin was lower on the ß-NGF + PBS side than on the control side, and that of neurofilament 160 was greater. On day 14, ß III-tubulin and protein gene product 9.5 were greater on the ß-NGF + PBS side than on the control side. Vascular endothelial growth factor expression was greater on the experimental side than the control side at 7 days, and vascular endothelial growth factor receptor 2 expression was elevated on days 14 and 21, but lower than control levels on day 28. However, no difference in the number of blood vessels was observed between sides. Our results indicate that topical application of ß-NGF promoted neurogenesis, and may modulate angiogenesis by promoting nerve regeneration in collagen bone substitute-filled defects.