AB47. Mechanism of the inhabition of transcription factor ZNF139 affecting on the apoptosis of the orthotopic implantation tumor of human gastric cancer in nude mice

Objective: The siRNA-ZNF139 was applied to silence the ZNF139 gene expression of orthotopic implantation tumor of human gastric cancer cell line SGC-7901 in nude mice. The purpose is to investigate the effect of siRNA-ZNF139 on the cell apoptosis of orthotopic implantation tumor of human gastric cancer in nude mice and the its mechanism.

Methods: The recombinant plasmid was extracted from the Endotoxin-free Kit. After the extraction, the concentration and purity of the extracted recombinant plasmid was examined by Ultraviolet spectrophotometer. The concentration and purity of the extracted plasmid examined by Ultraviolet spectrophotometer has reached the requirements of the follow-up experiment. The orthotopic implantation model of human gastric cancer in nude mouse was established, and tumor growth and weight were measured. The activity of gastric cancer cells in three groups was determined by MTT. The apoptosis rate of gastric cancer cells in nude mice in three groups was detected by the cell-flow. The expression of ZNF139, Bax and Bcl-2 mRNA of gastric cancer cell in nude mice was determined and compared by RT-PCR.

Results: Tumor growth was obviously suppressed and the tumor weight of nude mice was significantly smaller in the experimental group than in the blank control group and the negative control group. The results of MTT showed that the absorbance of gastric cancer cells in the blank control group (0.5014±0.0487) and in the negative control group (0.4926±0.0715) were significantly higher than that in the experimental group (0.2768±0.0048) (P<0.05). The results of the cell-flow showed that in the blank control group, the apoptosis of gastric cancer cells in nude mice (16.8300±3.6408)% and in the negative control group the apoptosis of gastric cancer cells in nude mice (16.0675±2.2041)% were significantly lower than that in the experimental group (32.5750±1.5025)% (P<0.05). The decrease of ZNF139 and Bcl-2 mRNA expressions were observed by RT-PCR in the experimental group. Bax mRNA expression was increased in the experimental group.

Conclusions: The targeted inhibition of ZNF139 gene by siRNA-ZNF139 could decrease the size and growth rate of orthotopic implantation tumor in nude mice. And the recombinant plasmid of siRNA-ZNF139 can effectively reduce the activity of the gastric cancer cell in nude mice and promote the apoptosis of the gastric cancer cells. The mechanism of cell apoptosis is that silencing the expression of ZNF139 can increase the expression of Bax and decrease the expression of Bcl-2, thereby inhibit the growth of the orthotopic implantation tumor of human gastric cancer in nude mice.

Keywords: Gastric cancer (GC); orthotopic transplantation model in nude mice; zinc finger protein 139; Bax; B-cell lymphoma-2 (Bcl-2); siRNA; recombinant plasmid; gene therapy