RESUMO
BACKGROUND: Recent studies have shown that matrix metalloproteinases (MMPs) from tumors influence the host immune system to reduce antitumor activity. The aim of this study was to examine the influence of MMP-2 and MMP-9 on the natural killer (NK) cell. MATERIALS AND METHODS: NK cells were pretreated with either MMP-2 or MMP-9 in the experimental group but not in the control group. NK cell cytotoxicity against oral squamous cell carcinoma cells (OSCC) were examined using the [Cr51] release assay and the expression levels of surface receptors on NK cells were measured by flow cytometry. RESULTS: NK cell cytotoxicity was significantly reduced in the experimental group compared to the control group. Significant increases in KIR expression and decreases in NKG2D expression on the NK cells were observed in the experimental group. CONCLUSION: This study suggests an additional role of MMP-2 and MMP-9 in an immune escape mechanism of OSCC.
