The Role Of CRL4^DCAF1 Ubiquitin Ligase-mediated Ubiquitination Of RNA Helicase DDX41 In Gastric Cancer

Gastric cancer is one of the most common malignant tumors in the world.In recent years,the incidence of gastric cancer in China has increased year by year,but the prognosis is poor while the recurrence rate is high.Tumor development is a multi-gene,multi-step process,include gastric cancer.The study of molecular mechanisms of tumors can not only assist in the diagnosis,predict the prognosis of patients,but also guide clinical treatment and provide new treatment options.DEAD box RNA helicase is one of the RNA helicase family members involved in the processing of m RNA precursors,RNA remodeling,ribosome synthesis,RNA transport and degradation.Many studies have shown that many DEAD box RNA helicases are abnormally expressed in tumor tissues,and their expression levels are closely related to tumor proliferation,metastasis,and prognosis,suggesting that such proteins play an important role in the development of tumors.As one of DEAD box RNA helicase members,DDX41 has been widely studied in hematological malignancies,but little research has been done in gastric cancer.Therefore,to study the mechanism of DDX41 in gastric cancer is of great significance for understanding the occurrence and development of gastric cancer.In the first part of this article,we investigated the expression of DDX41 in gastric cancer tissues and its effect on the proliferation of gastric cancer cells.The second part studies the molecular mechanism of interaction between DDX41 and ubiquitin ligase DCAF1 in gastric cancer.Part?Expression of DDX41 in Gastric Carcinoma and Its Relationship with Cell ProliferationObjective: To study the expression level and clinical significance of DDX41 in gastric cancer,and observe the effect of DDX41 on the proliferation of gastric cancer cells..METHODS: The website was used to analyze the expression of DDX41 in gastric cancer tissues and its clinical significance.Cloning formation assay was used to detect cell proliferation.Real-time quantitative PCR was used to detect the knockdown efficiency of si RNA.Wound scratch test was used to detect the effect of DCAF1 on cell migration.RESULTS: Compared with normal tissues,DDX41 expression was increased in gastric cancer tissues and increased in different stages of gastric cancer tissue samples.However,the expression level of DDX41 in gastric cancer tissues is not related to the prognosis of gastric cancer patients.Knockdown of DDX41 in gastric cancer cells MGC803 inhibited cell proliferation,but overexpression of DDX41 had no effect on cell proliferation.Knockdown of DDX41 in gastric cancer cells gc-006-03 had no effect on cell proliferation.Knockdown of DCAF1 in gastric cancer cells MGC803 inhibits cell migration,proliferation,and metastasis.CONCLUSION: In summary,the present study suggests that DDX41 expression is increased compared to normal tissues in gastric cancer tissues.DDX41 is involved in cell proliferation in gastric cancer cell MGC803,which may be a potential target for targeted therapy.DCAF1 is involved in the migration,proliferation and metastasis of gastric cancer cell MGC803,suggesting that DCAF1 plays an important role in the development of gastric cancer.Part? Molecular mechanism of interaction between DDX41 and ubiquitin ligase DCAF1 in gastric cancer cellsObjective: To study the molecular mechanism of DCAF1-mediated ubiquitination of RNA helicase DDX41.METHODS: The site predicts the presence of potential ubiquitylation binding sites in the RNA-helicase DDX family with DCAF1.The Western-blot assay detects the expression of the target protein in the cell.Co-immunoprecipitation assays detect the interaction between two target proteins.Co-immunoprecipitation assays were used to test the effect of two protein interactions on ubiquitination.RESULTS: DCAF1 and RNA helicase DDX1 bound to each other and affected the ubiquitination of DDX41.DCAF1-mediated ubiquitination of RNA helicase DDX41 had no effect on the half-life of DDX41.DCAF1 binds to DDX41 through the DEAD core conserved motif in DDX41.DCAF1 mediates the K63 polyubiquitination modification of the RNA helicase DDX41 via the HELICc region in DDX41.CONCLUSION: In summary,DCAF1 binds to DDX41 via the DEAD core conserved motif in DDX41 and via the HELIC region in DDX41 mediates the K63 polyubiquitylation modification of RNA helicase DDX41,but this polyubiquitylation modification has no effect on the half-life of DDX41.