SNAT1和EMP1在胃癌组织和细胞株中的表达及临床意义

Expressions and clinical significance of SNAT1 and EMP1 in gastric cancer tissue and cell lines

目的探讨人钠耦合中性氨基酸转运蛋白1(SNAT1)和上皮膜蛋白1(EMP1)在胃癌组织及胃癌细胞株中的表达水平,分析两者在胃癌组织中表达与临床病理特征的关系。方法采用免疫组化SP法检测82例胃癌组织和67例对应癌旁组织样本中SNAT1和EMP1的蛋白表达情况,根据二级计分法分为低表达(<5分)和高表达(≥5分),分析两者不同表达水平与胃癌临床病理特征的关系。同时采用Western blotting检测20例胃癌组织及其癌旁组织、正常胃黏膜上皮细胞株GES-1和胃癌不同分化细胞株(未分化BGC823、低分化AGS、中分化SGC7901和高分化MKN28)中SNAT1和EMP1的蛋白水平。结果胃癌组织的SNAT1高表达率高于癌旁组织(67.1%vs.34.3%,P<0.05),而EMP1高表达率则低于癌旁组织(40.2%vs.62.7%,P<0.05)。胃癌组织中SNAT1与EMP1表达呈负相关(r=-0.272,P=0.014),且两者表达与临床分期和分化程度均有关;另外,SNAT1与年龄、淋巴结转移有关,EMP1与浸润深度有关。胃癌细胞株中的SNAT1蛋白水平均高于癌旁组织和CES-1细胞,而EMP1蛋白水平则相反,差异均有统计学意义(P<0.05)。结论 SNAT1表达在胃癌组织及细胞株中分别较癌旁组织和正常胃黏膜细胞株高,EMP1则相反,胃癌组织中两种蛋白均与临床分期和分化程度有关,提示两者可能在胃癌的发生发展中起重要作用,可用于辅助胃癌的诊断和病情评估。

Objective To explore the expressions of sodium coupled neutral amino acid transporter 1 （SNAT1） and epithelial membrane protein （EMPI） 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 EMP 1 was 40.2% in cancer tissues, lower than 62.7% in paracancerous tissues （P〈0.05）. The expression of SNAT1 was negatively correlated with EMP 1 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.