Investigation On The Expression And Function Of DAPK In Bladder Cancer Cells

Death associated protein kinase 1(DAPK)is a serine/threonine kinase.Abnormal expression of DAPK is associated with the development of several cancers such as breast cancer,pancreatic cancer,cervical cancer,lung cancer and liver cancer.There is also a close relationship between DAPK and malignant metastasis.In recent years,many studies pointed out that the expression of DAPK in bladder cancer patients was low,and found that the low expression of DAPK was related to lymph node metastasis.However,the mechanism of how DAPK acts as a tumor suppressor in bladder cancer is not clear.Objective:the purpose of this study is to explore the clinical significance of DAPK in bladder cancer.Next we tried to explore DAPK related molecular mechanism in bladder cancer cell lines,so as to determine the clinical value of DAPK in the diagnosis and treatment of bladder carcinoma.Research methods:firstly,we analyzed the relationship between the expression of DAPK and the survival rate of the patients using database analysis.Using Tet-pLKO-shRNA plasmid,we established stable inducible DAPK knockdown bladder cancer cell lines.The stable cell lines were used in cell proliferation,colony formation assay,wound healing experiment and transwell experiments.In addition,based on the existing literature we investigated the downstream protein integrin in stable cell lines,so as to determine signal pathways regulated by DAPK.In the end,we screened some genes related to the expression of DAPK.Using those genes and small molecule drug interaction database,we screened the potential drugs related to those genes associated to the expression of DAPK and tried to provide the reference for the clinical treatment of bladder cancer patients.Results:The expression of DAPK was closely related to the survival rate of bladder cancer patients.At the same time,the functional results showed that DAPK does not affect the ability of proliferation,colony formation and migration,but it inhibits cells invasion.Inhibition of integrin reversed the effect of DAPK knockdown on invasion.We have identified TRAK1,ACOX1,UPK2 that are significantly related to DAPK expression.Through Significant Connection Map database we screened for potential drug related to those genes,and the results showed that vemurafenib has a significant correlation with those genes.The drug experiments confirmed that vemurafenib can enhance the expression of DAPK.Based on the above results,it is concluded that DAPK can improve the survival rate of patients with bladder cancer.Further study of bladder cancer cell function showed that DAPK couldinhibit the invasion of bladder cancer cells.In addition,the inhibition of integrin also showed that DAPK could affect the invasive ability of bladder cancer cells through integrin.These results suggested that DAPK may affect the invasive ability of bladder cancer cells by regulating integrin and its downstream proteins.Finally,through the screening of small molecule drugs related to those genes which are related to the expression of DAPK,we discovered that TRAK1,ACOX1 and UPK2 are significantly related to DAPK expression,and vemurafenib can improve the expression of DAPK through DAPK related genes.These results show that DAPK is an important factor in regulating the invasion in bladder cancer.DAPK may be a new drug target for the treatment of bladder cancer.