Long noncoding RNA TUG1 is a diagnostic factor in lung adenocarcinoma and suppresses apoptosis via epigenetic silencing of BAX.

Lung cancer is one of the leading causes of cancer-related mortality, and responds badly to existing treatment. Thus, it is of urgent need to identify novel diagnostic markers and therapeutic targets. Increasing evidences have indicated that long non-coding RNAs (lncRNAs) play an important role in initiation and progression of lung cancer. However, the role of lncRNA Taurine upregulated 1 (TUG1) in lung adenocarcinoma (LAD) progression is not well known. In this study, we determined the diagnostic value of TUG1 in LAD patients, and further uncovered the underlying functional mechanism. Our results showed that TUG1 was significantly upregulated in LAD cells and serum samples. Receiver operator characteristic (ROC) analysis suggested a relatively higher area under the curve (AUC) of TUG1 (0.756) contrast to cyfra21-1 (0.619). In addition, high TUG1 level was associated with enhanced tumor size, degree of differentiation, lymph node metastases, distant metastasis and TNM stage. Cell functional assays showed that knockdown of TUG1 suppressed LAD cell viability and promoted cell apoptosis. We then sought to reveal the underlying regulatory mechanism, and the pro-apoptotic protein BAX was then identified as the downstream target of TUG1. Gain and loss functional assays showed that inhibition of BAX reversed the induced apoptosis by TUG1 knockdown. Finally, RNA immunoprecipitation and Chromatin immunoprecipitation revealed that TUG1 suppressed BAX expression through physically interacting with EZH2. In conclusion, lncRNA TUG1 is a promising diagnostic marker for LAD patients and suppression of TUG1 levels could be a future direction to promote the prognosis of LAD patients.

[Suppression of VEGF protein expression by arctigenin in oral squamous cell carcinoma].

PURPOSE: To observe arctigenin's inhibitory effect on oral squamous cell carcinoma, and explore the possible mechanism. METHODS: The expression of VEGF in 32 cases of oral squamous cell cancer and 20 adjacent tissue specimen were detected with immunohistochemistry. Human nude mouse transplantation tumor model of oral squamous cell cancer was prepared with HSC-3 cells line. Transplanted tumor growth and VEGF expression in transplanted tumor tissues were assayed after treatment with arctigenin. One-way ANOVA was used for comparison between groups with SPSS 16.0 software package. RESULTS: Compared with the adjacent tissue, immunohistochemical staining score of VEGF was significantly higher (P<0.01) in oral squamous cell carcinoma tissues. After treatment with arctigenin, the growth of oral squamous cell transplanted tumors in nude mouse was inhibited (P<0.05), and decreased weight in end point of observation was noted (P<0.05). There were significant differences between high dose group and low dose group (P<0.05). Compared with the nude mouse model group, the optical density of VEGF staining was significantly lower in arctigenin group (P<0.05). There were significant differences between high dose group and low dose group (P<0.05). CONCLUSIONS: Arctigenin can dose-dependently inhibit the growth of oral squamous cell carcinomas, and this effect may be related to down regulation of VEGF expression.