Effect of Trichinella spiralis infection on expression and distribution of colonic epithelial E-cadherin in mice and its mechanism / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To study the effect of Trichinella spiralis (T.spiralis) infection on the expression and distribution of colonic epithelial E-cadherin in mice and its mechanism.</p><p><b>METHODS</b>BALB/c mice and STAT6-/- mice were infected with T.spiralis, and mice without infection were used as control. Seven days later, the horseradish peroxidase (HRP) was infused by rectal enema. Serum HRP was detected in the subsequent 0, 60 and 120 minutes. Then the mice were sacrificed and colon was taken out. The distribution of E-cadherin in colon was detected by immunofluorescence staining, and the expression of E-cadherin was detected by Western blot. The expression of interleukin-4 (IL-4) in mesenteric lymph nodes was detected by ELISA.</p><p><b>RESULTS</b>Serum HRP level in infected BALB/c mice was significantly higher than that in control mice (P<0.05), while it was not significantly different between infected STAT6-/- mice and controls (P>0.05). In infected BALB/c mice, E-cadherin located in cytoplasm of colonic epithelial cells, while in controls, it located in cellular membrane. E-cadherin expression down-regulated significantly in infected BALB/c mice as compared to controls. E-cadherin expression and distribution did not change obviously in infected STAT6-/- and control mice. IL-4 level in mesenteric lymph nodes of infected BALB/c mice [(193.0±12.5) μg/L] was significantly higher as compared to control BALB/c and infected STAT6-/- mice [(21.0±2.3) μg/L and (15.0±3.1) μg/L, all P<0.05].</p><p><b>CONCLUSION</b>T.spiralis infection can increase colonic epithelial permeability of mice, which may be associated with induction of Th2 cytokine secretion.</p>

Impact of fragile histidine triad gene transfection on the proliferation and apoptosis of human colorectal cancer cell / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the effect of fragile histidine triad (FHIT) gene transfection on human colorectal cancer cell line SW480 through up-regulation of caspase-8 expression.</p><p><b>METHODS</b>The eukaryotic expression plasmid containing FHIT, pRc/CMV2-FHIT was prepared and purified, and then identified by restrictive enzyme digestion. pRc/CMV2-FHIT was transfected into SW480 cells, and positive cell clones (SW480-FHIT, study group) were selected and amplified. Empty plasmid-transfected SW480 cells(SW480-pRc/CMV2, negative control) and normal SW480 cells (bland control) were used as control. Methyl thiazolyl tetrazolium (MTT) assay was used to test the changes in the proliferation of SW480 cells. Cell-cycle kinetics and apoptosis were analyzed by flow cytometry (FCM). The changes of pro-caspase-8, caspase-8 mRNA and caspase-8 relative activity were analyzed by Western blot, semi-quantitative RT-PCR and colorimetric assay with pan labeled substrate, respectively.</p><p><b>RESULTS</b>At 96 hours after transfection, cell inhibition rates of the study group and the negative control group were 71.7% and 16.9%. G0/G1 ratio was (63.2±3.5)% and (50.6±2.1)%, optical density of caspase-8 mRNA band 107 and 41, and relative activity of caspase-8 0.43 and 0.25, respectively. All the differences above were statistically significant (P<0.05). When FHIT inhibitor was added, the relative activity of caspase-8 decreased to 0.22, comparable to that in the control group.</p><p><b>CONCLUSIONS</b>FHIT gene transfection can significantly inhibit the proliferation and induce G0/G1 arrest in human colon cancer cell line SW480. The mechanism is related to the up-regulation of caspase-8 expression.</p>

Fragile histidine triad protein expression and correlation with apoptosis in rectal carcinoma / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the expression of fragile histidine triad (FHIT) protein and the clinicopathological characteristics of rectal carcinoma. The relationship between FHIT protein expression and Bcl-2, Bax and survivin expression, as well as cell apoptosis in rectal carcinoma were explored.</p><p><b>METHODS</b>Tissue microarray and immunohistochemistry SP were used to detect the expression of FHIT, Bcl-2, Bax and Survivin in 16 cases of normal rectal tissue, 16 cases of rectal adenoma and 80 cases of rectal carcinoma. TUNEL was used to detect apoptosis index (AI) in 80 cases of rectal carcinoma.</p><p><b>RESULTS</b>The positive rates of FHIT expression in normal rectal tissue, rectal adenoma and adenocarcinoma were 93.8%, 75.0% and 46.3% respectively. There were no significant differences between FHIT expression and histological types, gender and age (P>0.05). FHIT expression was significantly correlated with lymph node metastasis, Duke's stage and 5-year survival rate. The expression of FHIT was positively correlated with that of Bcl-2, Bax and survivin in rectal cancer. The mean AI in FHIT-negative tumors was significantly lower than that in FHIT-positive tumors (P<0.01).</p><p><b>CONCLUSIONS</b>The reduction of FHIT protein expression may play an important role in the development of rectal carcinoma, and FHIT protein may be associated with the regulation of cell apoptosis.</p>