The Effect Of Rnai In Mediated SOX2 And OCT4 Gene Silence On Human Gastric Cancer Cells

Background: Surgery, chemotherapy, radiotherapy and other traditional methods is difficult to curb the recurrence and metastasis of advanced gastric cancer. Cancer stem cells may one of the main factors of stomach cancer relapse and metastasis. At present there is no targeted treatment of cancer stem cells The transcription factor oct4 and sox2 in cancer stem cells still play an important role.They can maintain the cancer stem cell properties and functions. Interference with these genes is worth exploring for the inhibition of tumor stem cells.Objective:To investigate the effect of interference with transcription factor SOX2 and OCT4 on the cell apoptosis of grastric cancer cells.The angle of the cancer stem cell therapy for the new method. To open up new ways of treating cancer lay the theoretical and experimental basis.Materials and Methods:1.RT-PCR were used to detect the expression of SOX2 and OCT4.2. Chemotherapy treatment and enrichment of stem cells in gastric cancer cells.3. we tested before and after chemotherapy treatment of gastric cancer stem cells markers CD44 + in the proportion for Flow cytometry.4. To design and chemically synthesize siRNA targeted on SOX2 and OCT4. Transfected before and after chemotherapy treatment of gastric cancer stem cell. RT-PCR were used to detect the RNA interference effect.5. Flow cytometry tested before and after chemotherapy RNA interference and the OCT4 transcription factor SOX2 in gastric cancer cell cycle.6. MTT tested the effect of interference with transcription factor SOX2 and OCT4 on the cell apoptosis of before and after chemotherapy treatment gastric cancer cells.Results:1. Gastric cancer cell BGC-823 present in the expression of transcription factors SOX2 and OCT4.2. Most of gastric cancer cells died after chemotherapy treatment, living cells was 7±0.202%, cancer stem cells markers CD44 + of living cells was significantly higher proportion(before treatment0.74±0.052%;after treament 10.14±0.192%;P<0.01). Transcription factor SOX2 and OCT4 expression were significantly higher(before treatment SOX2 8±0.3%,OCT4 25±2.1%;after treament SOX2 20±0.41%,OCT4 83±4.7%;P<0.01)。After chemotherapy 5-FU treatment G0/G1 phase cells was significantly increased(before treatment G0/G1:68.19%±2.92%;after treament G0/G1:89.76%±4.93%;P<0.01),S phase cells decreased significantly(before treatment S:23.94%±1.98%;after treament S:0%;P<0.01). That 5-FU chemotherapy treatment of gastric cancer stem cells can be enriched.3. siRNA-sox2 and siRNA-oct4 transfected into gastric cancer cells, SOX2 expression increased from 8±0.3% before knockdown decreased to 1±0.2%, P <0.01. OCT4 expression increased from 25±2.1% before knockdown decreased to 2±0.4%.4..After siRNA knockdown gastric cell transcription factor SOX2 and OCT4. siRNA-SOX2 group, siRNA-OCT4,Together group comparison M/G2 percentage of cells were significantly decreased.No significant difference between the interference group. (M/G2:Control group7.87%±0.17%;siRNA-SOX2group M/G2:0.00%±0%;siRNA-OCT4group1.01%±0.02%,Together group 0.00%±0%). The interference group S phase fraction was significantly higher than the normal group (P <0.05), interference was no significant difference between groups. (S:Control group23.94%±1.98%;siRNA-SOX2group34.29%±5.89% ; siRNA-OCT4group34.97%±3.98% ; Together group 35.79%±3.74%)5. siRNA interference with gastric cancer cell line BGC-823 after the transcription factor SOX2 and OCT4, siRNA-SOX2 group, siRNA-OCT4 group, were respectively transfected with the control group (transfected with liposomes only, non-specific siRNA) compared to Slow down the proliferation of the peak latency P <0.01, the RNA interference was no significant difference between groups, after the chemotherapy drugs interfere with 5-FU, interference in each group compared with the control group significantly increased the sensitivity of P <O.O1, There was no difference in the interference. siRNA interference with 5-FU treatment of gastric cancer cells after siRNA-SOX2 group, siRNA-OCT4 group, co-transfection group compared with the control group were significantly inhibited proliferation, P <0.01,Conclusion:1, Human poorly differentiated gastric cancer cell line BGC-823 expressed stem cell associated transcription factor SOX2 and OCT4.2 Chemotherapy treatment of gastric cancer after gastric cancer cells significantly increased the proportion of stem cells, cancer stem cells can achieve the purpose of enrichment.3 Before chemotherapy treatment, RNA interference gene can slow the proliferation of cancer cells, the peak delay, and to the sensitivity of 5-FU increased significantly. After chemotherapy treatment, RNA interference can inhibit gastric cancer stem cell enriched cell proliferation, than continuous antitumor effect of chemotherapy drugs given to more significant. RNA interference and prompt chemotherapy combination therapy can enhance the efficacy of anti-tumor therapy.The purpose of transcription factor SOX2 and OCT4 in the maintenance of cancer stem cells play an important role in the process, is the future of cancer stem cell therapy is one potential target, through RNA interference interference stem cell related genes could be new strategy for the future treatment of cancer.