FOXD3 And ARK5 Involved In Cisplatin Resistance And Postoperative Pathological Staging Of Gastric Cancer Cells

Objective:Gastric cancer（GC）is one of the most common malignant tumors in the world and the fourth leading cause of cancer-related death.GC is a multifactorial disease.Both environmental and genetic factors can affect its occurrence and development.The incidence rate of GC gradually increased with age,with a median age of 70.However,about 10%of gastric cancer is found at the age of 45 or younger.Upper gastrointestinal endoscopy has been established as the gold standard for the diagnosis of gastric cancer.Endoscopic mucosal resection and endoscopic submucosal dissection were used to treat early GC.The survival and prognosis of the patients were significantly improved.For some advanced tumors,cisplatin-based chemotherapy can also improve the prognosis of patients.Then platinum-based drug resistance appeared,which seriously affected the survival outcome of patients.In recent years,research on the role of forkhead box family D3（FOXD3）and adenylate activated protein kinase 5（ARK5）in tumor progression has attracted more and more attention.However,the drug resistance of FOXD3 and ARK5 in gastric cancer cells and the differential expression of the two proteins in gastric cancer tissues have not been further explored.In this study,we mainly explore the role of forkhead box family D3（FOXD3）and adenosine monophosphate activated protein kinase 5（ARK5）in cisplatin resistance of gastric cancer cells,compare the expression differences of the two proteins in gastric cancer tissues and adjacent tissues,and compare the effects of the two proteins on the clinicopathology of gastric cancer.Methods:In this study,overexpression of FOXD3 in cisplatin resistant cell line SGC7901/DDP and silencing of ARK5 expression by RNAi technology were divided into six groups:gastric cancer cell line SGC7901（group 1）;gastric cancer drug resistant cell line SGC7901/DDP（group 2）;overexpression of FOXD3 protein SGC7901/DDP-FOXD3 group（group 3）;empty vector SGC7901/DDP-FOXD3-NC group（group 4）;knockdown ARK5 protein SGC7901/DDP-si ARK5-group（group 5）and knockdown empty vector SGC7901/DDP-si ARK5-NC group（group 6）.Western blot was used to detect the expression of FOXD3 and ARK5 in the six groups,and the half inhibitory concentration（IC50）of cisplatin was compared.The expression of FOXD3 and ARK5 in gastric cancer and adjacent tissues was detected by immunohistochemistry,and the influence of the difference of the expression of FOXD3 and ARK5 on clinicopathological features was analyzed.Results:The expression of FOXD3 in group 3（45.39±5.17）was significantly higher than that in group 1（27.15±7.53）,group 2（22.04±3.92）,group 4（23.39±2.56）,group 5（21.99±4.74）and group 6（24.27±5.39）（t=3.46,P=0.03;t=6.23,P=0.03;t=6.61,P=0.0027;t=5.78,P=0.004;t=4.90,P=0.05）;The expression of ARK5 in 5group（10.33±0.82）was significantly lower than that in 1 group（25.33±5.11）,2group（27.56±3.45）,3 group（27.82±5.40）,4 group（27.21±5.22）and 6 group（28.44±1.63）（t=5.02,P=0.007;t=8.42,P=0.001;t=5.54,P=0.005;t=5.53,P=0.005;t=17.19,P=0.000）.The IC50 of group 2 was（65.4±4.1）μg.m L-1,which was significantly higher than that of group 1（16.6±1.1）μg.m L-1,the IC50 of group 3was（13.5±0.9）μg.m L^-1,which was significantly lower than that of group 4（68.8±2.2）μg.m L^-1.The IC50 of group 5 was（15.1±2.8）μg.m L^-1,which was significantly lower than that of group 6（71.5±2.4）μg.m L^-1.The expression of FOXD3 was low in gastric cancer.ARK5 was highly expressed.The positive expression rate of FOXD3protein in patients with tumor diameter<5cm,T1+T2 and TNM stage I+II was significantly higher than that in patients with tumor diameter≥5cm,T3+T4 and III+IV（X²=4.68,P=0.03;X²=6.63,P=0.01;X²=37.91,P<0.001）.The positive expression rate of ARK5 protein in patients with T3+T4,lymph node metastasis and III+IV was significantly higher than that in patients with lymph node metastasis negative,T1+T2 and I+II（X²=36.01,P=0.000;X²=6.63,P=0.01）;The difference was statistically significant（X²=7.06,P=0.008;X²=30.85,P<0.001）.Conclusions:FOXD3 can inhibit the cisplatin resistance of gastric cancer cells,and ARK5 can promote the cisplatin resistance of gastric cancer cells.The abnormal expression of FOXD3 and ARK5 may participate in the cisplatin resistance of gastric cancer.