miR-34a-5p suppresses the invasion and metastasis of liver cancer by targeting the transcription factor YY1 to mediate MYCT1 upregulation.

BACKGROUND: In recent years, microRNAs (miRNAs) are reported to act as molecular biomarkers for cancer diagnosis, treatment, and prognosis (including liver cancer) and to be involved in the development and progression of cancer and other physiological and pathological changes. However, the role of miR-34a-5p in liver cancer is still largely unknown. METHODS: In our study, the expression of miR-34a-5p in liver cancer tissues and HCC cell lines was detected by qRT-PCR. The CCK-8, scratch wound-healing motility and Transwell assays were used to evaluate the effect on cell proliferation, migration and invasion. The expression of YY1, E-cadherin, N-cadherin and vimentin was analysed by western blotting. The dual luciferase assay was performed to confirm whether YY1 is a target of miR-34a-5p. The combination of YY1 and MYCT1 was detected by chromatin immunoprecipitation (ChIP) assay. RESULTS: The results showed that miR-34a-5p was downregulated in liver cancer tissues and HCC cell lines. Overexpression of miR-34a-5p inhibited the proliferation, migration and invasion of liver cancer cells. YY1 was a direct target of miR-34a-5p, and the expression of YY1 could reverse the influence of miR-34a-5p on the proliferation, migration and invasion of liver cancer cells. YY1 inhibited MYCT1 expression by directly binding to its promoter region, and knockdown of MYCT1 reversed the influence of miR-34a-5p on the proliferation, migration and invasion of liver cancer cells. CONCLUSION: Our results suggest that miR-34a-5p could inhibit the invasion and metastasis of hepatoma cells by targeting YY1-mediated MYCT1 transcriptional repression.

[Preliminary study of wireless biofeedback therapy for treatment of bruxism].

OBJECTIVE: To access the effect of wireless biofeedback therapy on bruxism. METHODS: Ten voluntary bruxers (seven female and three male, mean age 26.1 years) were invited to participate in this clinical research. An electric resistance strain gauge was embedded in the position of canine of a maxillary splint for monitoring the abnormal clenching or grinding movement of teeth during sleep. The relevant details of bruxism events, including value of relative force, occurring time and duration were recorded and analyzed by the receiver device and monitoring program respectively. Meanwhile, for the purpose of nerve system and muscle relaxation, a watch-style device around the patient's wrist will vibrate to alert the patient of teeth grinding or clenching if the value of biting force and duration exceed the threshold. Total average episodes of bruxism and duration was observed during eight hours sleep, and was analyzed with one-way analysis of variance in SPSS 19.0 by the end of 6th week and three months following biofeedback therapy. RESULTS: The average episodes of bruxism has declined dramatically from (9.8 ± 2.2) times to (3.0 ± 1.2) times during one night (P < 0.05), and the average duration of bruxism events was reduced from (20.7 ± 12.2) s to (10.0 ± 3.4) s (P < 0.05) after six weeks biofeedback therapy. By the end of three months, the average episodes declined to (2.9 ± 1.2) times (P < 0.05), and the average duration decline to (9.2 ± 2.9) s (P < 0.05) with contrast to preliminary night. CONCLUSIONS: The pressure-based wireless biofeedback device is able to monitoring clenching and grinding of bruxism. The results suggest that biofeedback therapy may be an effective, novel and convenient measure for treatment of bruxism according to several months therapy.