[Effects of S100A7 on the proliferation and invasiveness of esophageal squamous cell carcinoma EC9706 cells and possible mechanisms].

OBJECTIVE: To explore the expression of S100A7 in esophageal squamous cell carcinoma (ESCC) and examine the effect of S100A7 down-regulated expression mediated via RNA interfering on cell proliferation and invasion. METHODS: The expressions of S100A7 mRNA and protein were analyzed by in situ hybridization and immunohistochemistry.S100A7 siRNA was transfected into ESCC cell line EC9706 and the expressions of S100A7 mRNA and protein were detected by real-time polymerase chain reaction (PCR) and Western blot.Furthermore, the effects of down-regulated of S100A7 on cell proliferation and invasion were examine by Cell Counting Kit-8 (CCK-8) and Boyden chamber respectively.Finally the effect of down-regulated expression of S100A7 on matrix metalloproteinase-2 (MMP-2) protein was analyzed by Western blot. RESULTS: Positive expression ratios of S100A7 mRNA and protein expressions in ESCC tissues (72.0% and 69.3%) were significantly higher than those in normal esophageal tissues (10.7% and 8.0%) (χ² = 58.174 and 59.483, both P = 0.000). The expressions of S100A7 mRNA and protein in S100A7 siRNA group were markedly lower than those in untreated group (mRNA: 0.235 ± 0.056 vs 1, protein: 0.119 ± 0.025 vs 0.518 ± 0.129, both P < 0.05). Additionally, the down-regulated expression of S100A7 resulted in the proliferation inhibition and the decreased invasiveness in EC9706 cells. And it was coupled with a down-regulation of MMP-2 protein. CONCLUSION: S100A7 may play an essential role in the occurrence and development of ESCC and the decreased invasiveness of EC9706 cells mediated by the down-regulated expression of S100A7 may be closely associated with the down-regulation of MMP-2 protein.