Inhibition of the Tumor Suppressor Gene SPINK5 via EHMT2 Induces the Oral Squamous Cell Carcinoma Development.

Serine protease inhibitor Kazal-type 5 (SPINK5) has been revealed as a significant prognostic biomarker in oral squamous cell carcinoma (OSCC). However, there is little information regarding the detailed epigenetics mechanism underlying its dysregulation in OSCC. Using the Gene Expression Omnibus database, we identified SPINK5 as a significantly downregulated gene in OSCC tissues. Moreover, SPINK5 inhibited the malignant aggressiveness of HSC3 and squamous cell carcinomas (SCC)9 cells, whereas depletion of SPINK5 using shRNAs led to the opposite trend. The euchromatic histone lysine methyltransferase 2 (EHMT2) was found to bind to the SPINK5 promoter, and EHMT2 repressed the SPINK5 expression. SPINK5 reversed the stimulating effects of EHMT2 on the aggressiveness of HSC3 and SCC9 cells by impairing the Wnt/ß-catenin pathway. Wnt/ß-catenin inhibitor IWR-1 treatment reverted the malignant phenotype of OSCC cells in the presence of short hairpin RNA (sh)-SPINK5. Silencing of EHMT2 inhibited tumor growth and blocked the Wnt/ß-catenin signaling in OSCC, which was reversed by SPINK5 knockdown. Our study shows that SPINK5, mediated by the loss of EHMT2, can inhibit the development of OSCC by inhibiting Wnt/ß-catenin signaling and may serve as a treatment target for OSCC.

Exploration of proper heating protocol for injectable horizontal platelet-rich fibrin gel.

PURPOSE: Platelet-rich fibrin (PRF) has been proposed as promising biomaterials with the advantages of host accumulation of platelets and leukocytes with entrapment of growth factors and fibrin scaffold. However, limitations including fast resorption rate (~ 2 weeks) restricts its clinical application. Recent studies have demonstrated heating treatment can prolong PRF degradation. Current published articles used the method of 75 °C for 10 min to obtain longer degradation, while few studies investigated the most suitable temperature for heating horizontal PRF. Our present study was to discover and confirm the optimum temperature for heat treatment before obtaining H-PRF gels by investigating their structure, mechanical properties, and bioactivity of the H-PRF gels after heating treatment. METHODS: In the present study, 2-mL upper layer of horizontal PRF was collected and heated at 45 °C, 60 °C, 75 °C, and 90 °C to heat 2-mL upper layer of horizontal PRF for 10 min before mixing with the 2-mL lower layer horizontal PRF. The weight, solidification time and the degradation properties were subsequently recorded. Scanning electron microscopy (SEM) and rheologic tests were carried out to investigate the microstructure and rheologic properties of each H-PRF gel. The biological activity of each H-PRF gel was also evaluated using live/dead staining. RESULTS: H-PRF gel prepared at 75 °C for 10 min had the fast solidification period (over a tenfold increase than control) as well as the best resistance to degradation. The number of living cells in H-PRF gel is greater than 90%. SEM showed that H-PRF gel becomes denser as the heating temperature increases, and rheologic tests also revealed that the heat treatment improved the mechanical properties of H-PRF gels when compared to non-heated control group. Future clinical studies are needed to further support the clinical application of H-PRF gels in tissue regeneration procedures. CONCLUSIONS: Our results demonstrated that the H-PRF gel obtained at 75 °C for 10 min could produce a uniform, moldable gel with a short time for solidification time, great rheologic behavior and, high percent of live cells in PRF gel. A promising use of the commonly utilized PRF gel was achieved facilitating tissue regeneration and preventing degradation.

Long non-coding RNA SAMMSON as a novel potential diagnostic and prognostic biomarker for oral squamous cell carcinoma.

BACKGROUND/PURPOSE: Oral squamous cell carcinoma (OSCC) is one of the most lethal malignancies which accounts for approximately 90% of all malignant oral tumours. SAMMSON is a lncRNA located on chromosome 3p13-3p14 and is known to act as an oncogene in several malignancies. However, its expression and clinical significance in oral squamous cell carcinoma (OSCC) remain mostly unclear. In this study, we investigated the expression and clinical relevance of lncRNA SAMMSON in human OSCC. MATERIALS AND METHODS: Human OSCC cell lines (Tca8113, SCC9, SCC25, CAL27, HN12, HSU3, FADU) and a human normal oral keratinocyte cell line (HNOK) were used to detect the difference of SAMMSON expression. A total of 90 OSCC patients confirmed by pathological and clinical diagnoses at the Hospital of Stomatology, Department of Periodontology, Shandong University were enrolled. The mRNA expression level was analyzed by reverse transcription PCR (QRT-PCR). Statistical analyses including Student's t-test, chi-square method, Kaplan-Meier method, Univariate and, Multivariate Cox regression analysis were performed to analyse all data. RESULTS: This study showed that the expression of SAMMSON was significantly increased in OSCC tissues and cell lines. High SAMMSON expression was significantly associated with TMN stage, tumour differentiation, lymph node metastasis distant metastasis and neighboring tissue infiltration. Patients with high expression of SAMMSON had poor overall survival and disease-free survival compared to those with low levels. Cox regression analysis showed that SAMMSON could act as an independent prognostic factor in OSCC. CONCLUSION: Serum SAMMSON expression was associated with tumour SAMMSON expression. ROC curve analysis indicated the high diagnostic sensitivity and specificity of serum SAMMSON expression in OSCC patients as compared to other traditional serum biomarker SCCA, TSGF, and CEA. These results indicated that SAMMSON might play an essential role in OSCC progression and could serve as a novel prognostic and diagnostic biomarker in OSCC.