Relationship between expression of gastrin, somatostatin,Fas/FasL and caspases in large intestinal carcinoma

AIM: To explore the correlation between the mRNAs and protein expression of gastrin (GAS), somatostatin (SS) and apoptosis index (AI), apoptosis regulation gene Fas/ FasL and caspases in large intestinal carcinoma (LIC). METHODS: Expression of GAS and SS mRNAs were detected by nested RT-PCR in 79 cases of LIC. Cell apoptosis was detected by molecular biology in situ apoptosis detecting methods (TUNEL). Immunohistochemical staining for GAS, SS, Fas/FasL, caspase-3 and caspase-8 was performed according to the standard streptavidin-biotin-peroxidase (S-P) method. RESULTS: There was a significant positive correlation between mRNA and protein expression of GAS and SS (GASrs=0.99, P < 0.01; SSrs = 0.98, P < 0.01). There was significant difference in positive expression rates of GAS, SS mRNAs and protein among different histological differentiation, histological types and Dukes’ stage of LIC. The AI in GAS high and moderate expression groups was significantly lower than that in low expression groups (3.75 ± 2.38 vs 7.82 ± 2.38, P < 0.01; 5.51 ± 2.66 vs 7.82 ± 2.38, P < 0.01), and the AI in SS high and moderate expression groups was significantly higher than that in low expression groups (9.03 ± 1.76 vs 5.35 ± 3.00, P < 0.01; 7.44 ± 2.67 vs 5.35 ± 3.00, P < 0.01). There was a significant negative correlation between the integral ratio of GAS to SS and the AI (rs = -0.41, P < 0.01). The positive expression rate of FasL in GAS high and moderate expression groups was higher than thatin low expression group (90.9% and 81.0% vs 53.2%, P < 0.05). The positive expression rates of Fas, caspase-8 and caspase-3 in SS high (90.0%, 90.0% and 100%) and moderate (80.0%, 70.0%, 75.0%) expression groups were higher than that in low expression group (53.1%, 42.9%, 49.0%) (90.0% and 80.0% vs 53.1%, P < 0.05; 90.0% and 70.0% vs 42.9%, P < 0.05; 100.0% and 75.0% vs 49.0%, P < 0.05). There was a significant positive correlation between the integral ratio of GAS to SS and the semiquantitative integral of FasL (rs = 0.32, P < 0.01). CONCLUSION: GAS and SS play important roles in the regulation and control of cell apoptosis in LIC, and the mechanism may be directly related to the aberrant expression of Fas/FasL. The GAS and SS will be valuable targets of the biological behavior of LIC.

Role of ERK-MAPK signaling pathway in pentagastrin-regulated growth of large intestinal carcinoma

AIM: To explore the role and mechanisms of extracellular signal-regulated protein kinase-mitogen-activated protein kinase (ERK-MAPK) signaling in pentagastrin-regulated growth of large intestinal carcinoma.

IMMUNOCYTOCHEMICAL STUDY OF ENTEROCHROMAFFIN CELLS IN CARCINOMAS OF THE LARGE INTESTINE

In a series of 130 cases of adenocarcinomas of the large intestine, enterochromaffin (EC) cells were detected in 54 cases (41.3%) by limmunocytochemistry with anti-chromogranin monoclonal antibody. Among the 54 cases, 30 were found positive for serotonin, 14 for somatostatin, 11 for glucagon, 5 for pancreatic polypeptide, and only one for gastrin. The cases with EC cell (++) or polypeptide positive cells exhibited higher grade of differentiation, earlier stage of tumor extension and higher survival rate than those without EC cells. A significant difference of the EC cell population pattern among different histological grades of the tumors and non-neoplastic mucosa was found. The proportion of hormone, especially polypeptied positive cells was the highest in the mucosa and lowest in the moderately or poorly-differentiated carcinomas. The incidence, methodology and clinicopathological significance of EC cells found in the tumors are discussed.

Correlation between expression of gastrin, somatostatin and cell apoptosis regulation gene bcl-2/bax in large intestine carcinoma

AIM: To explore the correlation between expression of somatostatin (SS), gastrin (GAS) and cell apoptosis regulation gene bcl-2/bax in large intestine carcinoma.METHODS: Sixty-two large intestine cancer tissue samples were randomly and retrospectively selected from patients with large intestine carcinoma. Immunohistochemical staining for bcl-2, bax, GAS, SS was performed according to the standard streptavidin-biotin-peroxidase (S-P) method.According to the semi-quantitative integral evaluation, SS and GAS were divided into three groups as follows. Scores1-3 were defined as the low expression group, 4-8 as the intermediate expression group, 9-16 as the high expression group. Bax and bcl-2 protein expressions in different GAS and SS expression groups of large intestine carcinoma were assessed.RESULTS: The positive expression rate of bax had a prominent difference between SS and GAS high, intermediate and low expression groups (P＜0.05, x2ss = 9.246; P＜0.05,x2GAS = 6.981). The positive expression rate of bax in SS high (80.0%, 8/10) and intermediate (76.5%, 13/17)expression groups was higher than that in low expression group (40.0%, 14/35) (P＜0.05, x2high vs low = 5.242; P＜0.05,x2middle vs low = 6.097). The positive expression rate of bax in GAS high expression group (27.3%, 3/8) was lower than that in low expression group (69.4%, 25/36) (P＜0.05,x2 = 4.594). However, bax expression in GAS intermediate expression group (46.7%, 7/15) was lower than that in low expression group, but not statistically significant. The positive expression rate of bcl-2 had a prominent difference between SS and GAS high, intermediate and low expression groups (P＜0.05, x2ss = 7.178; P＜0.05, x2GAS = 13.831). The positive expression rate of bcl-2 in GAS high (90.9%, 10/11)and intermediate (86.7%, 13/15) expression groups was higher than that in low expression group (44.4%, 16/36)(P＜0.05,x2high vs low = 5.600; P＜0.05, x2 middle vs low = 7.695).However, the positive expression rate of bcl-2 in SS high (40.0%, 4/10) and intermediate (47.1%, 8/9) expression groups was lower than that in low expression group (77.1%, 27/35)(P＜0.05, x2 high vs low = 4.710; P＜0.05, x2 middle vs low = 4.706).There was a significant positive correlation between the integral ratio of GAS to SS and the integral of bcl-2 (P＜0.01,r=0.340). However, there was a negative correlation between the integral ratio of GAS to the SS and bax the integral of (P＜0.05, r = -0.299).CONCLUSION: The regulation and control of gastrin,somatostatin in cell apoptosis of large intestine carcinoma may be directly related to the abnormal expression of bcl-2, bax.

Sulindac induces apoptosis and protects against colon carcinoma in mice

AIM: To study the effect of sulindac on colon cancer induction in mice. METHODS: The chemo-preventive action of 80 ppm sulindac fed during initiation and post-initiation and 100 ppm sulindac fed during progressive stages of induction of colon carcinogenesis in mice was investigated using 1,2-dimethylhydrazine (DMH). Using the terminal deoxynudeobdyl transferase-mediated dUTP nick-end labeling (TUNEL) technique and PCNA immunohistochemical staining, we observed the apoptotic and proliferative cell density changes at different carcinogenic stages and the effect of sulindac on these two phenomena. RESULTS: Dietary sulindac significantly inhibited the incidence of colonic neoplasmas in mice. Compared with the control group, feeding sulindac during initiation and post-initiation stages inhibited the incidence by 46.7-50.4%, and feeding sulindac during progressive stages inhibited the incidence by 41.1%. Animals that were fed sulindac showed less serious pathological changes than those that were fed the control diet (P<0.01, H=33.35). There was no difference in the density of proliferating cells among those groups which were or were not fed sulindac. In the same period, feeding sulindac resulted in a higher density of apoptotic cells than feeding control diet. CONCLUSION: Sulindac has an anti-carcinogenic function in mice. Its effect on preventing colon carcinogenesis is better than its effect on treating established tumors. By inducing apoptosis, sulindac inhibited the development of colon cancer and delayed canceration. Sulindac has no effect on proliferation. The anti-carcinogenic properties of sulindac are most effective in the moderate and severe stages of dysplasia and canceration.