OBJECTIVETo explore the NEK-6 expression in gastric cancer tissue and its relationship with clinicopathological features.

METHODSFluorescent quantification PCR and Western blotting were used to examine the NEK-6 expression in 36 samples of fresh gastric cancer tissues and para-cancer gastric mucosal tissues, human gastric cancer cell lines(BGC-823, MKN-28, SGC-7901, MGC-803, HGC-27, AGS), and human normal gastric epithelial cell line (GES-1). Gastric cancer cell lines with the highest expression level were selected to perform the invasion and migration tests, and the effect of down-regulated NEK-6 expression by siRNA transfection on above invasion and migration tests were observed. Meanwhile NEK-6 expression in 94 paraffin samples of gastric cancer tissues was examined by immunohistochemistry and its positivity was compared among different clinicopathologic features.

RESULTSFluorescent quantification PCR revealed gastric cancer tissues had significantly higher NEK-6 expression than para-cancer tissues(0.002 80±0.001 36 vs. 0.001 91±0.001 48, P<0.05), NEK-6 expression was up-regulated in 31 gastric cancer tissues (86.1%), and human gastric cancer cell lines had significantly higher NEK-6 expression than GES-1 cells, among whom BGC-823 and AGS cell lines were the highest. Invasion and migration tests showed that as compared to negative siRNA control group, ability of invasion and migration in BGC-823 and AGS cells after siRNA transfection was obviously decreased. In 94 paraffin samples, positive expression rate of NEK-6 was 60.6%(57/94), and NEK-6 expression was significantly associated with gastric cancer distant metastasis, lymph nodes metastasis and TNM staging(all P<0.05).

CONCLUSIONSNEK-6 expression is up-regulated in gastric cancer tissues, which is significantly associated with distant metastasis, lymph nodes metastasis and TNM staging. Down-regulation of NEK-6 expression can inhibit the ability of invasion and migration in gastric cancer cells.