Study On The Role And Mechanism Of Targeting MUS81 Combined With WEE1 Inhibitors In Gastric Cancer

Objective: To investigate the molecular sensitized the anti-tumor effect of targeting MUS81 in gastric cancer and the mechanism.Methods: The data of gastric cancer in TCGA database were analyzed,and the differential genes of patients with high and low expression of MUS81 were compared,and gastric cancer samples were collected for immunohistochemical staining for verification.Lentivirus was used to knock down the expression of MUS81 in gastric cancer cell lines,and the effect of targeting MUS81 combined with MK1775 on the proliferation of gastric cancer cells was investigated by MTT assay and colony formation assay.Then flow cytometry was used to analyze the effect of targeting MUS81 combined with MK1775 on apoptosis and cell cycle of gastric cancer,and immunofluorescence analysis was used to analyze the effect of DNA damage of gastric cancer cells.In addition,the xenograft model was used to explore the anti-tumor effect of the combination in vivo level.Results: Bioinformatics analysis showed that there was a negative correlation between the expression of MUS81 and WEE1 in gastric cancer,and the expression of WEE1 was high in patients with low expression of MUS81.Immunohistochemical staining of gastric cancer tissue samples from our center also showed a negative correlation between the expression of MUS81 and WEE1.The results of MTT and colony formation assay showed that targeting MUS81 combined with MK1775 could significantly inhibit the proliferation of gastric cancer cells,which was better than that of single treatment.Moreover,the results of cell cycle test,apoptosis test and immunofluorescence showed that the combination could promote gastric cancer cell apoptosis,cell cycle arrest and DNA damage.In vivo,targeting MUS81 combined with MK1775 could significantly inhibit the growth of gastric cancer transplanted tumor,and the effect of combined treatment was significantly better than that of single treatment.Also,the body weight of mice did not decrease significantly,indicated that the toxicity could be controlled.The immunohistochemical results showed that the levels of cleaved-caspase3,cleaved-PARP and γ H2 AX in the targeting MUS81 plus MK1775 group were significantly higher than those in the single treatment group and the control group,while the Ki67 index was significantly lower than that in the single treatment group and the control group.Conclusion: There is a negative correlation between the expression of MUS81 and WEE1 in gastric cancer;targeting MUS81 combined with WEE1 inhibitors can lead to DNA damage and cell cycle arrest,which can inhibit the proliferation of gastric cancer cells and lead to apoptosis.