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>

Experimental study of NK4 gene targeted therapy mediated by human telomerase reverse transcriptase promoter for colon cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate anti-tumor effect of the recombined adenovirus encoding NK4 gene regulated by human telomerase reverse transcriptase (HTERT) promoter (Ad HTERTp-NK4) on human colon cancer.</p><p><b>METHODS</b>Colon cell line HCT116 was infected with Ad HTERTp-NK4. NK4 expression was determined by RT-PCR and Western blot. The cell-growth inhibition rate and the invasive capacity of cells were evaluated by MTT method and reconstituted basement membrane invasion assay. The model of subcutaneous tumor was generated by injection of HCT116 cells into the dorsum of nude mice. Ad HTERTp-NK4 was injected around the tumor tissues, and tumor growth was observed.</p><p><b>RESULTS</b>NK4 gene was highly expressed in infected HCT116 cells. The cell growth inhibition rate and the invasive inhibition rate in Ad HTERTp-NK4 cells were 47.14% and 40.63% respectively, which were significantly higher than those in the control cells (2.75% and 2.31%, P<0.05). Tumor growth was significantly inhibited in mice injected with Ad HTERTp-NK4, and the tumor growth inhibition rate was 47.3%, which was significantly higher than that in the controls (4.6%, P<0.05).</p><p><b>CONCLUSION</b>Ad HTERTp-NK4 can inhibit tumor growth and decrease the invasive capacity of tumor cells, which makes it an ideal candidate for new gene therapy for colon carcinoma.</p>