Abstract:

Objective To explore the expressions of sodium coupled neutral amino acid transporter 1 （SNAT1） and epithelial membrane protein （EMP1） in gastric cancer tissue and cell lines， and analyze their relationship with clinicopathological features of gastric cancer. Methods The immunohistochemistry SP method was used to detect the expressions of SNAT1 and EMP1 in tissue sections from 82 gastric cancer and 67 paracancerous tissues from our hospital. The expression level was divided into low-level expression（＜5 points） and high-level expression（≥5 points） according to the two grade score. Then the relationships between expressions of SNAT1 and EMP1 and clinicopathological variables were analyzed. Meanwhile， the Western blotting method was employed to detect the protein level of SNAT1 and EMP1 in 20 paired cancer and paracancerous tissues as well as normal gastric mucosa cell （GES-1） and different cancer cell lines of various differentiation（BGC823， SGC7901， AGS and MKN28）. Results The high-level expression rate of SNAT1 in cancer tissues were 67.1％， higher than 34.3％ in paracancerous tissues （P＜0.05）， while the high-level expression rate of EMP1 was 40.2％ in cancer tissues， lower than 62.7％ in paracancerous tissues （P＜0.05）. The expression of SNAT1 was negatively correlated with EMP1 in cancer tissues （r=-0.272， P=0.014）. Both expressions were related with clinical stage and differentiation degree. In addition， the SNAT1 expression was related with age and lymph node metastasis， and the EMP1 expression was related with invasive depth （P＜0.05）. Compared with the paracancerous tissues and normal gastric mucosa cell，there existed higher protein level of SNAT1 but lower protein level of EMP1 in gastric cancer tissue and cell lines （P＜0.05）. Conclusion Both SNAT1 and EMP1 were related with clinical stage and differentiation degree， suggesting playing a important role in the development of gastric cancer. Both proteins can facilitate the diagnosis and evaluation of gastric cancer.