PURPOSE

To investigate the molecular mechanism of LncRNA NEAT1 regulating proliferation, migration and invasion of tongue squamous cell carcinoma cells by regulating miR-339-5p/ITGA3 axis.

METHODS

qRT-PCR and Western blot were used to detect the expression of NEAT1, miR-339-5p, ITGA3 mRNA and ITGA3 protein in 25 cases of human tongue squamous cell carcinoma, its corresponding adjacent tissues, human normal oral mucosal cell line HOK and human tongue squamous cell carcinoma cell lines TSCCA, CAL27, SCC15 and HN13. CAL27 cell lines that inhibited NEAT1 and overexpressed miR-339-5p were constructed, respectively. Cell viability was detected by MTT assay, cell numbers of migration and invasion were detected by Transwell assay, and the expression of Cyclin D1 and MMP-9 proteins were detected by Western blotting. The dual luciferase reporter gene was used to verify the targeting relationship of NEAT1, miR-339-5p and ITGA3, and the regulatory relationship was detected by Western blotting and qRT-PCR. SPSS 17.0 software package was used for statistical analysis of the data.

RESULTS

Compared with normal human oral mucosal cell line HOK, the expression of NEAT1 and ITGA3 was up-regulated, while the expression of miR-339-5p was down-regulated in human tongue squamous cell carcinoma cell lines. Inhibition of NEAT1 or over-expression of miR-339-5p significantly inhibited proliferation, migration and invasion of CAL27 cells, and significantly inhibited expression of Cyclin D1 and MMP-9 proteins. Dual luciferase reporter gene assay confirmed that NEAT1 directly interacted with miR-339-5p and suppressed its expression. miR-339-5p negatively regulated ITGA3 expression. Inhibition of NEAT1 reversed the inhibitory effect of the inhibition of miR-339-5p on proliferation, migration and invasion of CAL27 cells.

CONCLUSIONS

LncRNA NEAT1 promotes proliferation, migration and invasion of tongue squamous cell carcinoma cells by down-regulating miR-339-5p/ITGA3 axis.