The present study evaluated the expression and potential role of CD63 in the migration and invasion of tongue squamous cell carcinoma (TSCC) cells. Immunohistochemistry (IHC) was used to investigate the association between the expression level of CD63 protein and the histological differentiation of samples from 40 patients with TSCC and four normal tongue tissue specimens. RNA interference (RNAi) and gene transfection technology were used to alter the expression of CD63 in TCA8113 cells. The stable silencing and overexpression of CD63 in the TCA8113 cell line was used to assess the impact of the CD63 expression level on the migratory and invasive abilities of TCA8113 cells in a wound healing assay and a Transwell invasion assay. The effect of CD63 on the expression of matrix metalloproteinase (MMP)-2 and -9 were evaluated by western blot analysis. The results of IHC revealed a positive association between the CD63 expression level and the histopathological differentiation of TSCC and a negative association between the CD63 expression level and lymph node metastasis in TSCC. Western blotting revealed that the expressions of MMP-2 and MMP-9 were clearly upregulated in CD63-silenced TCA8113 cells but reduced in CD63-overexpressing TCA8113 cells, compared with the control. The wound-healing speed and the number of cells invading Matrigel-coated filters were negatively associated with the CD63 expression level. In summary, the results of the present study revealed that CD63 may be an inhibitor of TSCC malignancy and lymph node metastasis and may have applications in the prediction of prognosis and gene therapy for patients of TSCC.
Keywords: RNA interference; cluster of differentiation 63; invasion; migration; tongue cancer.