MicroRNA-1258, regulated by c-Myb, inhibits growth and epithelial-to-mesenchymal transition phenotype via targeting SP1 in oral squamous cell carcinoma.

The biological function and underlying mechanism of miR-1258 has seldom been investigated in cancer progression, including in oral squamous cell carcinoma (OSCC). In the current study, we revealed that the expression level of miR-1258 was significantly down-regulated in OSCC tissues and cell lines. Restoration of miR-1258 decreased OSCC cell growth and invasion. The luciferase and Western blot assays revealed that SP1 protein was a downstream target of miR-1258. Overexpression of SP1 dismissed miR-1258's effect on cell growth and invasion. We also revealed that c-Myb inhibited miR-1258 by directly binding at its promoter. In addition, miR-1258 inhibited PI3K/AKT and ERK signalling pathway activity. Taken together, these findings demonstrated that miR-1258 may function as a tumour-suppressive micorRNA in OSCC and suggested that miR-1258 may be a potential therapeutic target for OSCC patients.

Association of MTHFR C677T and A1298C polymorphisms with oral cancer susceptibility: evidence from a meta-analysis.

Methylenetetrahydrofolate reductase (MTHFR) is a central enzyme involved in folate metabolism and plays an important role in DNA synthesis and methylation. Several studies have been conducted to illustrate the associations between MTHFR C677T and A1298C polymorphisms with oral cancer susceptibility; however, the results are inconsistent. Therefore, we conducted an updated meta-analysis to obtain a more reliable estimation of the associations. We retrieved eligible studies from PubMed, EMBASE, and CBM databases through September 2016. Ultimately, pooled analyses involved 10 studies with 1443 cases and 1640 controls for the C677T polymorphism, as well as five studies with 973 cases and 1024 controls for the A1298C polymorphism. Risk estimates were presented as odds ratios (ORs) and 95% confidence intervals (95% CIs). Pooled results indicated that neither C677T nor A1298C polymorphism was associated with oral cancer susceptibility. However, a borderline significant association was detected between MTHFR C677T polymorphism and a decreased oral cancer risk (homozygous model: OR=0.71, 95% CI=0.50-1.00) in hospital-based studies. Our results suggested that MTHFR C677T and A1298C polymorphisms might not be associated with oral cancer risk. However, more evidence is needed to further confirm these findings in the future.

[Mechanism of combined use of cyclopamine and hydroxycamptothecin in inducing the apoptosis of human oral squamous cell carcinoma cell line].

OBJECTIVE: To study the mechanism underlying the effect of combined use of cyclonpamine and hydroxycamptothecin in inducing the apoptosis of human oral squamous cell carcinoma cell line (OSCC) HSQ-89. METHODS: CCK8 assay was used to investigate the inhibitory effect of cyclopamine on HSQ-89 cells. Flow cytometry (FCM) was employed to examine the cell apoptosis following combined treatment with cyclonpamine and hydroxycamptothecin. Reverse transcription polymerase chain reaction (RT-PCR) was applied to detect the mRNA expressions of Bcl-2, Bcl-xl, and Bid in HSQ-89 cells after the treatments. RESULTS: Combined treatment with cyclonpamine and hydroxycamptothecin significantly inhibited the cell proliferation compared with hydroxycamptothecin treatment alone, also resulting in a significantly higher apoptosis rate of the cells (P<0.05). The mRNA level of Bcl-2 was significantly decreased after the treatments, especially after the combined treatment. Cyclopamine produced no significant effect on the mRNA levels of Bcl-xl and Bid in the cells. CONCLUSION: The combined use of cyclopamine and hydroxycamptothecin significantly down-regulates the expression on of bcl-2 to induce the apoptosis of human OSCC cell line HSQ-89.

[Clinical value of PET in identifying cervical nodal metastases of tongue cancer: a comparison with CT/MRI and clinical palpation in 38 cases].

OBJECTIVE: To assess the value of PET in the identification of cervical nodal metastases of tongue cancer in comparison with CT/MRI and clinical palpation. METHODS: Thirty-eight patients with tongue cancer underwent PET and CT/MRI within 2 weeks before surgery. The results of PET, CT/MRI, and clinical palpation were interpreted separately to assess the regional lymph node status, using histopathological analysis as the golden standard. The differences in the sensitivity, specificity and accuracy among the imaging modalities and clinical palpation were analyzed. RESULTS: The sensitivity of PET for nodal metastasis identification was 11.1% higher than that of CT/MRI (83.3% vs 72.2%, P=0.423) and 16.6% higher than that of clinical palpation (83.3% vs 66.7%, P=0.248). The specificity of PET was 5% higher than that of CT/MRI (80% vs 75%, P=0.703) and 15% higher than that of clinical palpation (80% vs 65%, P=0.288). The accuracy of PET, CT/MRI, and clinical palpation in identifying cervical nodal metastases was 81.6%, 73.7% and 65.8%, respectively. CONCLUSION: The sensitivity, specificity and accuracy of PET for detecting cervical nodal metastases are greater than those of CT/MRI and clinical palpation. Although the results failed to show statistically significant differences, we still recommend that PET be used as a supplementary modality for identifying nodal metastases of tongue cancer.

[Epigallocatechin-3-gallate induces G1 phase cell cycle arrest in KB cells].

OBJECTIVE: To explore the effects of epigallocatechin-3-gallate (EGCG) on the proliferation of human oral epithelial cancer cell line KB cells and the molecular mechanisms. METHOD: KB cells were treated with various concentrations of EGCG for 24 or 48 h. MTT assay was used to test the cell viability. The changes of cell cycle in KB cells treated with EGCG for 48 h were analyzed using flow cytometry. The expressions of cyclin A, cyclin D1 and cyclin E were detected by RT-PCR and Western blotting. RESULT: The viability of KB cells treated with various concentrations of EGCG (25, 50, 100, 200, 400, and 800 micromol/L) for 48 h were decreased to (85.4-/+2.4)%, (80.4-/+2.8)%, (51.5-/+4.5)%, (30.2-/+1.9)%, (25.3-/+1.5)%, (20.0-/+1.1)%, respectively, showing significant difference from that of the control group [(100.0-/+2.2)%, P<0.05). EGCG decreased the viabilities of KB cells in a dose-dependent manner. Flow cytometry demonstrated that treatment with EGCG significantly increased the cell percentage in sub-G1 phase, which was (73.5-/+4.4)% after a 48-h EGCG treatment, significantly different from that in the control group [(47.3-/+3.5)%, P<0.05). EGCG-induced G1 phase arrest was correlated to the down-regulation of cyclin A and cyclin E. CONCLUSION: EGCG inhibits the proliferation of KB cells by inducing G1 phase arrest, which involves the downregulation of cyclin E.

[Clinical application of positron-emission tomography for the identification of cervical nodal metastases of head and neck cancer compared with CT or MRI and clinical palpation].

OBJECTIVE: To evaluate the value of positron-emission tomography (PET) for the identification of cervical nodal metastases of head and neck cancer compared with CT/MRI and clinical palpation. METHODS: Forty patients of head and neck cancer underwent PET and CT/MRI examination 2 weeks before surgery. PET, CT/MRI and clinical palpation were interpreted separately to assess regional lymph node status. Histopathologic analysis was used as the gold standard for assessment of the lymph node involvement. Differences in sensitivity, specificity and accuracy among the imaging modalities and clinical palpation were analyzed. RESULTS: The sensitivity of PET for the identification of nodal metastases was 14.3% higher than that of CT/MRI (P = 0.648) and 14.3% higher than that of clinical palpation (P = 0.648), whereas the specificity of PET was 15.4% higher than that of CT/MRI (P = 0.188) and 7.7% higher than that of clinical palpation (P = 0.482). The accuracy of 18F-FDG PET, CT/MRI, and clinical palpation for the identification of cervical nodal metastases was 85.0%, 70.0% and 75.0% respectively. CONCLUSIONS: The sensitivity, specificity and accuracy of PET for the detection of cervical nodal metastases was higher than that of CT/MRI and clinical palpation. Although the results did not show a statistically significant difference, PET can still serve as a supplementary method for the identification of nodal metastases of head and neck cancer.