未折叠蛋白反应相关因子GRP78、ATF6和XPB1在人食管鳞状细胞癌中的表达及其意义

Expression and significance of unfolded protein response related factors( GRP78,ATF6 and XPB1) in human esophageal squamous cell carcinoma

目的了解食管鳞状细胞癌(ESCC)组织中未折叠蛋白反应(UPR)相关因子GRP78、ATF6、XPB1的表达情况,探讨UPR激活在ESCC发生和发展中的作用。方法选取经手术切除确诊的ESCC癌组织、正常食管黏膜组织各99例,应用免疫组化SP方法检测GRP78和ATF6的蛋白表达情况;应用RT-PCR方法分析XBP1两种不同的亚型(非剪接型XBP1-u和剪接型XBP1-s)的分布情况。结果 GRP78和ATF6在ESCC组织中阳性率分别为67.7%和62.6%,而正常食管组织中阳性率分别为37.4%和35.6%,差异均显著(P<0.05);ESCC中GRP78和ATF6表达与肿瘤分化程度、临床分期、淋巴结转移均有相关性(P<0.05)。RT-PCR结果显示,XBP1-s基因在ESCC和正常食管组织中均有表达,分别为0.446±0.033和0.217±0.018,差异显著(t=60.6153 P<0.05);XBP1-s基因在ESCC组织中表达与肿瘤分化程度、临床分期、淋巴结转移均有相关性(P<0.05);而XBP1-u基因在两组细胞中的表达差异不显著(P>0.05)。结论在ESCC细胞中,由于UPR被激活,ATF6信号转导通路和IRE1依赖的XBP1剪切机制被活化。UPR与ESCC的发展、浸润、转移相关,也许能对ESCC诊疗提供新思路。

Objective To detect the expression of unfolded protein response （UPR） related factors GRP78,ATF6,and XPB1 in esophageal squamous cell carcinoma （ESCC） tissues,and to explore the role of UPR activation in the carcinogenesis and development of ESCC.Methods 99 cases of ESCC and corresponding normal esophageal mucosa were collected.The expression of GRP78 and ATF6 proteins was detected by immunohistochemical SP method,RT-PCR analysis was used to examine two different subtypes of XBP1 （non-splicing type XBP1-u,splicing XBP1-s）.Results The positive rated of GRP78 and ATF6 in ESCC tissues and normal esophageal tissues positive rates were 67.7%,37.4% and 62.6%,35.6%,respectively,the difference was statistically significant （x2 =20.024,P 〈 0.05; x2 =20.485,P 〈0.05）.GRP78 and ATF6 expression in ESCCs were related to tumor differentiation,clinical stage,lymph node metastasis （P 〈 0.05）.RT-PCR results showed that XBP1-s mRNA expression in ESCC tissues was higher than that in normal esophageal tissues（0.446 ± 0.033 vs 0.217 ± 0.018,t =60.6153,P 〈 0.05）.There was a positive correlation between XBP1-s gene expression and tumor differentiation,clinical stage,lymph node metastasis in ESCCs（P 〈 0.05）.However,XBP1-u gene expression in ESCCs and normal esophageal mucosa was 0.191 ± 0.016 and 0.188 ± 0.013 with the difference was not statistically significant （P 〉 0.05）.Conclusion In ESCCs,UPR is activated,ATF6 signal transduction pathways and IRE1-dependent XBP1 splice mechanism is activated.UPR may be associated with the development of ESCC,invasion and metastasis,which may provide new ideas for the diagnosis and treatment of ESCC.