The Research Of Correlation Between STAT1 And Survivin And Their Clinical Pathological Significance In Gastric Cancer

AIM: Gastric carcinoma was one of the commonest malignancies in China. There is evidence supporting that apoptosis is bloched in gastric cancer . Survivin is a new number of IAP families and is a powerful apoptosis repression factor. It is found during embryonic and fetal development but is completely down-regulated and undetectable in normal adult tissues and becomes prominently expressed in many human malignancies. Survivin has negtive correlation of apoptosis in gastric cancer. "There are a few literatures about its function, the mechanims of its function and its clinical significances in gastric cancer. Signal transducer and activator of transcription 1 (STAT1) is a promoter of apoptosis. There is no literature about its function, the mechanims of its function and its clinical significances in gastric cancer. We had discovered they would regulate apoptosis at the same points, and there would be correlation of them. There is no literature about this problem.Lymph node metastasis was the most important marker of prognosis of gastric cancer. If number of lymph node examnation is no enough, the result of this examation will be not accurate. AJCC/UICC recommend every case of gastric cancers must examine more than 15 lymph nodes. Nowadays, there were a few examinations could reach this standard, and few could collect whole lymph nodes. The researches based in this examination are not accurate.Firstly, we planned collected specimens of curative dissection that had complete lymph node examination data and other pathological examination data. Using tissue microarray and the immunohistochemical method to observe STAT1, Survivin and some other correlative apoptosisi regulater in human gastric cancer at the first time, then reaserch the possible correlation between STAT1, Survivin, correlative apoptosisi regulater and pathological features, and the correlation between molecule markers, approach the clinical significance of STAT1 and Survivin, the way they regulate apoptosis and the correlation between them.Secondly, we used gastric cancer SGC7901 cell, Using IFN-γ,STAT1 antisense oligonucleotide and Survivin antisense oligonucleotide to treat SGC7901, and viewing the change of STAT1, Survivin and the correlative apoptosis regulation gene by immunogical cell chemical and image analysis methods, and using Hoechest33258 to view the change of apoptosis, reaserching their functions, the mechanims of their functions and the correlation between them. The research of the regulation apoptosis way of STAT1 in gastric cancer will offer the proof of apoptosis regulation mechanism in gastic cancer and will offer the new idea and targeting in therapy of gastric cancer.METHODS: Specimens of curative dissection between 1988 and 2003 were collected. SGC7901 cell has been adopted. All 140 patients' all lymph nodes were found by clearing fat method, the interrupted serial 4-micron sections, routine hematoxylin and eosin staining and immunohistochemical methods (CK₁₈+EMA) were used to detect the lymph node metastases. The complete pathological examination data had been collected at the same time. Follow-up was asked by telephone and clinical examination. They all had had gastroscope examination at least once. Gastric cancer tissue microarray were formed and tested the expression of STAT1, Survivin, caspase3, caspase7, p53 and PTEN in gastric cancer by immunohisto'chemical method. Using IFN-γ,STAT1 antisense oligonucleotide and Survivin antisense oligonucleotide to treat SGC7901, and viewing STAT1, Survivin and the correlation apoptosis regulation gene by immunogical cell chemical and image analysis methods. Using Hoechest33258 to view the change of apoptosis. All data was processed using X² test, Fisher exact test, Spearman rank correlation analysis, Life-table method, Cox multivariate analysis and t test (SPSS 12.0 software).RESULTS:1. The utilization rate of 140-specimen gastric cancer tissue microarray was 83.3%. The correlation of molecule markers:Survivin had negative correlation of STAT1( x²=4.11, P=0. 043) and caspase3( x²=5.76, P=0.02). Survivin also had positive correlation of PTEN(x²=4.17, P=0.04).STAT1 had positive correlation of caspase3( x²=13.33, P<0.001) and caspase7 (x²=5.84, P=0.016).Caspase3 had positive correlation of caspase7( x²=23.98, P<0.001).PTEN had positive correlation of p53 (P=0.048) analyzed by Fisher exact test.2. All 140 patients had complete examination data (99 males, 41 females; median age, 58 years; ranging from 26 to 72 years). Median size of tumor is 5.4 cm (range from 0.8 to 15 cm). Depth of invasion is T₁ 16, T₂ 22, T₃ 45, and T. 57. Specimens of well differentiation gastric adenocarcinoma are 52 and poor differentiation gastric adenocarcinoma is 88.8892 lymph nodes were found (63. 5/case, range, from 17 to 157 nodes, median number, 61 nodes, 95%CI: 59-68) and metastases were found in 102 cases and 1824 lymph nodes (UICC N stage, N₀ 38, N₁ 34, N₂ 30, and N₃ 38) by clearing fat method. The correlation between molecule markers and pathological features:UICC N stage: Survivin had negative correlation of UICC N stage(P=0.04). Other molecule markers had no correlation of UICC N stage.Depth of invasion: STAT1 (r=-0. 21,P=0.03) had positive correlation of depth of invasion. PTEN (P=0.02) had negtive correlation of depth of invasion. Histological classification: Survivin expression was higher in well differentiationthan in poor differentiation (x²=4.83, P=0.03). STAT1 expression was lower in well differentiationthan in poor differentiation (x²=10.2, P=0.0014). p53 expression was lower in well differentiation than in poor differentiation (x²=7.21, P=0.007). PTEN expression was higher in well differentiationthan in poor differentiation(x²=5.47, P=0.02). Other molecule markers had no correlation of histological classification.Heterogenous: Caspase3 expression was higher in having heterogenous gastric cancer than no heterogenous gastric cancer ( x.²=7.36, P=0.007). Other molecule markers had no correlation of heterogenous.Age: p53 expression was lower in < 60 years old group than in ≥60 years old group (x²=7.20, P=0.007). PTEN expression was lower in < 60 years old group than in ≥60 years old group (x²=4.37, P=0.04). Other molecule markers had no correlation of age.Sex: All molecule markers had no correlation of sex.3. 110 patients were follow-up by telephone asks and clinical examination. They all had had gastroscope examination at least once, before 2005. 7. Depth of invasion (x²=7.26, P=0.007) and UICC N stage(x²=4.01, P=0.045) predicted a significantly increased risk of death with gastric cancer. Other pathological features and molecule markers had no correlation of prognosis.4. When using IFN-γ to stimulate SGC7901 cell, STAT1, caspase7 and p21WAF increased significantly (P<0.05) , and Survivin was inhibited significantly (P<0.05) . Using IFN-γ to stimulate SGC7901 cell, at the same time, using STAT1 ASON of different concentration to inhibit STAT1, STAT1, caspase7 and p21WAF were inhibited in different degree (P<0.05) , and Survivin increased in different degree (P<0.05) .5. When using Survivin ASON of different concentration to inhibite Survivin, Survivin was inhibited in different degree (P<0.05) , STAT1 increased in different degree (P<0.05) , and caspase7 and p21WAF did not change (P>0.05) .6. In different treatment group, the apoptosis state of SGC7901 cell did not change (P>0.05) .CONCLUSION:1. In gastric cancer tissue, STAT1 expression had the positive correlation of caspase3 and caspase7 expression. Survivin expression had the negtive correlation of caspase3 expression. STAT1 expression had the negtive correlation of Survivin expression. These evidences show STAT1 and Survivin all could regulate apoptosis by caspase3 and there was correlation between STAT1 and Survivin in gastric cancer.2. The expression of STAT1 and Survivin were important in development of gastric cancer. STAT1 expression can be a molecular marker to predict advanced gastric cancer in gastric cancer. Survivin can be a molecular marker of lymph node metastasis in gastric cancer.3. Survivin expression had negtive correlation of UICC N stage, and was higher in well differentiation gastric cancer. STAT1 expression had negtive correlation of depth of invasion, and was higher in poor differentiation gastric cancer. These evidences show gastric cancer had the more malignant would have more apoptosis.4. UICC N stage and the depth of cancer is the most important prognostic factor in gastric caner.5. In gastric cancer cell SGC7901, STAT1 could up-regulate caspase7 and p21waf in gastric cancer cell SGC7901. These evidences show STAT1 could regulate apoptosis by caspase7 and p21waf. Survivin had no correlation of regulation of caspase7 and p21waf. These evidences show Survivin could not regulate caspase7 and p21waf. This result was accord with Survivin regulating apoptosis by binding with caspase7 and p21waf.6. STAT1 and Survivin could down-regulate each other in gastric cancer cell SGC7901. These evidences show the point that STAT1 regulating apoptosis involve Survivin.7. There have several inhibition ways of apoptosis in gastric cancer cell SGC7901.