Toll-Like Receptor 2 Promotes Invasion by SGC-7901 Human Gastric Carcinoma Cells and Is Associated with Gastric Carcinoma Metastasis

Toll-like receptors (TLRs) play a key role in cancer metastasis. The biological role of TLR2 in invasion and metastasis in gastric carcinoma cells and gastric carcinoma is not clear; therefore, we aimed to investigate the biological role of TLR2 in invasion by SGC-7901 human gastric carcinoma cells and to determine whether TLR2 is associated with gastric carcinoma metastasis. RT-PCR, real-time PCR, flow cytometry, and western blotting showed that TLR2 activation significantly increased TLR2 expression at the mRNA and protein levels and notably promoted the transcription of genes related to angiogenesis and invasion, such as VEGF-C and MMP-9. The invasive capacity of SGC-7901 cells was strikingly advanced by TLR2 stimulation on Transwell invasion assay. IL-6 in the supernatants of cultured SGC-7901 cells was increased under the condition of TLR2 stimulation and reduced after TLR2 blockade by ELISA. Combined with clinicopathological parameters, the expression of TLR2 protein examined by immunohistochemical analysis was higher in gastric carcinoma tissues than in adjacent non-cancerous tissues (p<0.001). There was a significant relationship between TLR2 expression and lymph node metastasis (p<0.01), distant metastasis (p<0.01). There was no significant correlation between gastric carcinoma and age (p>0.05), sex (p>0.05), or degree of differentiation (p>0.05). These findings indicate that TLR2 may participate in the progression and metastasis of human gastric carcinoma and provide a new therapeutic target against metastasis of gastric carcinoma.