Expression And Significance Of Unfolded Protein Response Related Factors (GRP78、ATF6and XPB1) In Human Esophageal Squamous Cell Carcinoma

Background and PurposeEsophageal cancinoma（EC) of digestive system cancer is a common threat tohuman life and health.Esophageal squamous cell carcinoma (ESCC) is the mainlesions in esophageal squamous epithelium of the esophagus cancer, esophagealcancer cases in China for more than about95%of esophageal squamous cellcarcinoma.Currently, the incidence and mortality of esophageal cancer are high. Thenumber of new cases per year worldwide is about400,000cases,but each year about30million people die of the disease; China as the world’s one of the areas of highincidence of esophageal cancer, the incidence rate is about13/100000, with anaverage of150,000deaths/year.Studies have shown that patients with earlyesophageal cancer if timely and effective treatment,5-year survival after thetreatment can reach more than90%; due to the development and progression ofesophageal cancer was gradually evolved resistance, early symptoms are not obvious,coupled with early screening and diagnosis deletions, etc., admission first diagnosedin advanced cases, mostly after treatment,5-year survival rate of less than10%. Presently, Esophageal cancinoma treatment approach to including surgical,radiotherapy, chemotherapy and biological therapy, although in recent years withthe development of esophageal cancer diagnosis and treatment techniques, survivaland quality of life of patients has a corresponding increase,but the overall treatmenteffect is not satisfactory.Thus at this stage of esophageal cancer research focused onhow early detection of cancer, how to use the correct way of treatment of esophagealcancer, improve the therapeutic effect and increase the quality of life and delay thepatient’s life.Esophageal squamous cell carcinoma is knowed as a common digestive cancer,and its occurrence and development is a multi-step process of multi-gene mutations,but tumor growth are related with metabolism and growth scores, self-programmedcell death and other factors.The unfolded protein response is knowed as theendoplasmic reticulum stress one important type, presently study indicates thattumor occurrence may be closely related to the development,metastasis andprognosis.Because of their uncontrolled growth and proliferation consume large amountsof nutrients and oxygen, coupled with inadequate blood supply and other reasons,the solid tumor cell growth process prevalened hypoxic microenvironment,nutritional deficiencies, PH and changes in circumstances, in such adverseenvironmental impact, the cells can be induced Ca2+balance disorders, endoplasmicreticulum accumulation of misfolded protein synthesis, causing endoplasmicreticulum stress occurs.As an important branch of ERS,the unfolded protein responseis a highly evoluted conservation cellular response mechanisms, by inhibitingprotein translation, inducing molecular chaperone protein synthesis within the ERS,increasing protein folding capacity, promoting protein transport and unfolded proteindegradation, in order to restore ERS homeostasis.This enhanced tumor cell viabilitygrowth in harmful factors, it may be to raise the degree of malignancy of tumor cellsand increase the migration rate of the important mechanisms, while continuing orexcessive UPR can lead to apoptosis of tumor cell death.Currently,there are threeactivation pathways preacher the unfolded protein response in mammals:thedouble-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase (PERK) signaling pathway；type-1endoplasmic reticulum transmembrane proteinkinase (IRE1) signal transduction pathway；activation of the transcription factor6(ATF6) signal transduction pathway.Complicated by factors related to the role ofparticipation is completed, the main parameters of the main signaling moleculeshave GRP78, IRE1, ATF6, XBP1and PERK and so on. Glucose regulated protein of78as the most important chaperonin UPR and regulation of transcription factors,UPR process, significantly increased levels of transcription, can be considered amarker of activated UPR; Activating transcription factor6during transit is UPRimportant endoplasmic reticulum stress signal transduction proteins, which leaddirectly to the activation of the UPR pathway downstream ATF6transcriptionalactivation element, which can be used in the activation of specific activation of theUPR pathway ATF6; X box-bindingpro tein1is activator UPR target genes in theIRE1UPR signal transduction pathway, inositol requiring1its specific cut, splicednon-type XBP1-u into splicing XBP1-s, thereby increasing the activity of and triggerdownstream effects, thus differentially expressed non-spliced and splicedXBP1-u-type type XBP1-s determines the activation of UPR in IRE1pathway.Presently, UPR in many solid tumors, such as breast, stomach, liver, bile ductcancer, prostate cancer,is activated, but the study is activated in ESCC tissues andits mechanism of action is not perfect.ERS including tumor cells, UPR as potentialdrug targets have generally people’s attention, along with in-depth study of thetheory and ERS perfect, so we expected to happen on the molecular mechanisms oftumor development more fully understand and provide cancer prevention pathwaysand therapeutic targets.The experiments were conducted using immunohistochemical SP and RT-PCRassay ESCC tissues GRP78, ATF6expression and RT-PCR and XPB1and analyzeits ESCC tissues and normal esophageal differences between tissues and its clinicaland pathological features between patients, investigate the existence of ESCC tissuesand its UPR,development and prognosis and tumorigenesis significance. For thediagnosis and treatment of esophageal cancer provides new ideas.Objects and Methods1.Collect the Second Affiliated Hospital of Zhengzhou University of Thoracic Surgery between November2011to September2013was resected andpathologically confirmed primary ESCC tissues and tissues from cancer surgerymore than5cm distal border of each99normal esophageal mucosa patients beforesurgery in all cases without radiotherapy and chemotherapy treatment. Of which62were males and37females; aged38to73years,≤60years old in27cases,>60years72cases. degree of differentiation: poorly differentiated in32cases,53casesof differentiated, well differentiated14cases; lymph node metastasis: lymph nodemetastasis in30cases,69cases without lymph node metastasis.2.Methods SP immunohistochemical detection of the expression GRP78andATF6proteins in99cases of esophageal squamous cell carcinoma andcorresponding normal tissues; application by RT-PCR analysis of XBP1twodifferent subtypes (non-splicing type XBP1-u, splicing type XBP1-s) expressiondistribution in esophageal squamous cell carcinoma and corresponding normalesophageal tissues; and separately analyzed he expression level andclinicopathological features relationships GRP78, t ATF6, XBP1-u, XBP1-s.Using statistical software SPSS17.0was used for statistical analysis, carried outusing the χ2test comparison of qualitative data between the two groups, GRP78andATF6protein expression in comparison with pairedχ2test ESCC tissues and normalesophageal tissue; in ESCC tissues the expression of independent samplesχ2test;compared using test conducted between two quantitative data, XBP1-u and XBP1-smRNA relative expression in ESCC tissues and normal esophageal tissue volumeusing a paired t test; XBP1-s mRNA expression in ESCC tissues using independentsample t test case. Test levelα=0.05.Results1. GRP78expression67/99(67.7%) in99cases of ESCC tissues high normalesophageal tissue expression37/99(37.4%), the difference was statisticallysignificant (P <0.001).2. GRP78expression in high, medium and low differentiation group incrementswere6/14(42.9%),35/53(66%),26/32(81.3%), three differences statisticallysignificant (P<0.05); expression in group with lymph node metastasis high thosegroup without lymph node metastasis,the26/30(86.7%),41/69(59.4%) were significantly significant (P <0.05). GRP78expression was not related with genderand age (P>0.05).3. In99cases of ESCC tissues,ATF6expression62/99(62.6%) high normalesophageal tissue35/99(35.6%), the difference was statistically significant(P<0.001).4. ATF6expression in high, medium and low differentiation group incrementswere5/14(35.7%),32/53(60.4%),25/32(78.1%), three groups differencesstatistically significant (P<0.05);expression25/30(83.3%) in lymph node metastasisthan those without lymph node metastasis expression37/69(53.6%),there weresignificantly significant(P<0.05). ATF6expression was not related with gender andage (P>0.05).5. XBP1-s mRNA expression0.446±0.033in ESCC tissues high normalesophageal tissues expression0.217±0.018, there was significant difference (P<0.05).6. XBP1-s mRNA in the expression0.437±0.035of well-differentiated grouplow poorly differentiated group expression0.450±0.041, there were significantlysignificant (P<0.05); expression0.448±0.040in lymph node metastasis group washigher than without lymph node metastasis expression0.436±0.032, there weresignificantly significant (P<0.05). XBP1-s mRNA expression was not related withgender, age and other factors(P>0.05).7. XBP1-u mRNA expression in ESCC tissues and normal esophageal tissueswere0.191±0.016,0.188±0.013, there were not significantly significant(P>0.05).8. XBP1-u mRNA expression expression was not related with gender, age,differentiation, lymph node metastasis and other clinicopathological features (P>0.05).Conclusion1. GRP78, ATF6and XBP1-s mRNA is highly expressed in esophagealsquamous cell carcinoma and the expression of XBP1-u mRNA has no difference inthe two tissues, these suggest that activation of the unfolded protein responsesituation exists in esophageal squamous cell carcinoma; The open ATF6signalingpathway in the unfolded protein response involved in the occurrence of esophageal squamous cell carcinoma; The open IRE1signaling pathway in the unfolded proteinresponse involved in the occurrence of esophageal squamous cell carcinoma;Unfolded protein response is associated with the occurrence of esophageal squamouscell carcinoma.2. In esophageal squamous cell carcinoma, the expression of GRP78, ATF6andXBP1-s mRNA have no correlation with patient’s sex and age; However, Theexpression of GRP78, ATF6and XBP1-s mRNA are correlated with the degree ofdifferentiation, lymph node metastasis. These results suggest that the unfoldedprotein response involved in the development of esophageal squamous cellcarcinoma.Activation of the unfolded protein response is positively related to tumormalignancy and invasiveness in esophageal squamous cell carcinoma.