The Influence Of DOK2 On The Biological Behavior Of Gastric Cancer Cells And Its Relationship With The Prognosis Of Gastric Cancer

Background:Gastric cancer is a gastrointestinal cancer, especially in South-East Asian countries,including China.In recent years, more than 80% of gastric cancer diagnosis occurred in the late stages of the disease, the primary means for cancer treatment such as surgery, radiotherapy and chemotherapy in patients with advanced part already powerless, or recurrence, metastasis, is difficult to achieve cure. Although medical researchers have been working to improve the gastric cancer prevention, diagnosis and treatment, the overall survival of patients is poor,5-year survival rate is about 30% after surgery. Therefore, how to inhibit tumor growth and improve the prognosis is one of the key to tumor therapy.The development of gastric cancer is caused by a variety of factors, multi-step and multi-stage, which is characterized by the activation and inactivation of tumor suppressor genes oncogenes. Epigenetic changes, especially the change of tumor related gene, plays a very important role in the occurrence and development of tumor. DOK2 is a tumor suppressor gene,located on human chromosome 8P21.3. Currently, DOK2 were studied as a tumor suppressor gene in ovarian cancer, lung cancer, colorectal cancer. And DOK2 gene can be used as a molecular marker of poor prognosis after surgery. However, the role of DOK2 gene on the development of gastric cancer is not clear, which will be studied in this article.Objective:To detect the DOK2 expression of human gastric cancer tissues, and analyze its over-expression in gastric cancer cell BGC823 proliferation, colony formation and independent suspension. To explore its clinical significance.Methods:1 DOK2 expression was detected by RT-PCR method in seven gastric cancer cell lines(AGS、BGC-823、SGC7901、MKN28、NCI-N87、MKN45、SNU1)and normal gastric tissues.2 Establish a kill curve of G418 for BGC823 cells, confirm the optimum kill concentration.3 The recombinant plasmids pc DNA3.1-DOK2 and pc DNA3.1 empty vector construction.And they were transfected into gastric cancer cells BGC-823 using Lipofectamine 2000. The expression of DOK2 gene was detected by RT-PCR and Western Blot in BGC823 cells.4 We evaluated the influence of over-expression of DOK2 on gastric cancer cells biological behavior by CCK8, soft agar, colony formation assay.5 The expression of DOK2 protein was detected by immunohistochemistry in 116 cases of gastric carcinoma, and its relationship with clinicopathological characteristics and prognosis of gastric cancer was analyzed.Results:1 DOK2 expression in gastric cancer cells was remarkablely reduced in contrast to normal gastric tissue.2 The optimum concentration to obtion stable transfected BGC823 cells was 500 μg/ml.3 We established a stable over expression of DOK2 in BGC823 cell lines as well as empty vector control cell lines.4 Over-expression of DOK2 in gastric cancer cells with endogenous silencing led to strong inhibition of cell growth,proliferation,colony formation of gastric cancer cells BGC823.5 Immunohistochemistry showed the low expression of DOK2 protein in gastric cancer accounted for 62.93%, and DOK2 protein expression had a significant inverse correlation with depth of tumor invasion, lymph node metastasis and tumor differentiation degree; DOK2 protein expression, depth of tumor invasion, lymph node metastasis, distant metastasis and tumor differentiation degree were important factors affecting the prognosis of patients survival.Conclusion:1 DOK2 is low expression or absent in human gastric cancer and gastric cancer cell lines.2 DOK2 significantly inhibit the biological behavior of gastric cancer cells BGC823, such as proliferation, colony formation and independent suspension ability.3 DOK2 expression is correlate with the prognosis of patients with gastric cancer.