[Expression of thioredoxin reductase 1 (TrxR1) in gastric cancer and its effect on the growth of gastric cancer cells].

ABSTRACT

OBJECTIVE: To investigate the relationship between the expression of thioredoxin reductase 1 (TrxR1) in gastric cancer tissues and the survival time of patients with gastric cancer and its effect on the growth of gastric cancer cells. METHODS: The expression level of TrxR1 mRNA in gastric cancer tissues and adjacent tissues of 76 patients was determined by real-time PCR assays, and the relationship between the mRNA expression level of TrxR1 and the clinicopathological characteristics and prognosis of gastric cancer patients was analyzed. Three gastric cancer tissues and adjacent tissues were randomly selected, and the expression of TrxR1 protein was detected by immunohistochemistry and Western blot. The expression levels of TrxR1 in human gastric cancer cells line and gastric mucosa epithelial cells were determined by Western blot and quantitative real-time PCR assays. Then, AGS cells were transfected with siRNA sequences to silence the expression of TrxR1. AGS cells were divided into 3 groups according to different processing negative control group transfected with NC-siRNA, TRXR1 siRNA interference group 1 transfected with TRXR1-siRNA1, TRXR1 siRNA interference 2 group transfected with TRXR1-siRNA2. The expression of TrxR1 mRNA in AGS cells of each group was detected by Real-time PCR. The proliferation of AGS cells was determined by MTT and colony formation assays following TrxR1 silencing. RESULTS: TrxR1 mRNA and protein expression levels in gastric cancer tissues were significantly up-regulated compared with adjacent tissues, and were mainly located in the cytoplasm. High expression of TrxR1 was associated with TNM stage and lymph node metastasis, and the overall survival time of patients with high expression of TrxR1 was shorter than those with low expression level. TrxR1 mRNA and protein in AGS cells of TRXR1-siRNA1 group and AGS cells of TRXR1-siRNA2 group were significantly reduced compared with NC-siRNA group (P＜0.05). And AGS cell clone formation and proliferation ability were decreased. CONCLUSION: The high expression of TrxR1 in gastric cancer tissues indicates poor prognosis of patients, and the silencing of TrxR1 can inhibit the proliferation of gastric cancer cells.