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>

Influence of liver regeneration after partial hepatectomy on the development of liver metastasis of colon cancer in rats / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the stimulated effect of liver regeneration on colon cancer cells in remnant liver in rats.</p><p><b>METHODS</b>Rat models with liver metastases or retro-peritoneal metastases of colon cancer were established: animals underwent 37% or 70% liver resection and were compared with a sham laparotomy (15, 25, 15 cases, respectively). Metastases were performed two weeks before resection. Rats were killed 3 weeks after the resection. Total body weight, liver and tumor weights were recorded. The human colon adenocarcinoma cell line Lovo was cultured in the presence of portal serum withdrawn 24 hours and 14 days after partial hepatectomy (PH). DNA synthesis was assessed by flow cytometry analysis for 5-Bromodeoxyuridine (5-BrdU) incorporation.</p><p><b>RESULTS</b>The tumor growth was accelerated in the remnant liver in 70% PH group, but the tumors in 37% PH group and retro-peritoneal site were not influenced by PH. Compared with the control group, after cultured 72 hours with portal serum withdrawn 24 h after PH, a higher 5-BrdU incorporation was found in the Lovo cell lines (P < 0.05), and it reached the peak after 120 hours of culture (P < 0.05). No difference was found between the groups when cultured with the portal serum withdrawn 14 d after PH (P > 0.05).</p><p><b>CONCLUSIONS</b>PH may accelerate the growth of residual microscopic tumor in the liver which contributes to local recurrence. It has no systemic effect and effects on the cancer cell lines in extrahepatic sites. The excision extension is related to the stimulating effects on the cancer cell line, and subtotal hepatectomy is presumably a major determinant.</p>