Mechanism Of YWHAG In The Proliferation And Invasion Of Gastric Cancer

Objective: Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein γ（YWHAG）,as a member of the phosphorylated regulatory protein family,was abnormally overexpressed in a variety of malignant tumors and participated in the malignant progression of cancer.However,the specific mechanism of YWHAG remains unknown in gastric cancer.This study aimed to investigate the biological role of YWHAG in gastric cancer and elucidate its possible underlying molecular mechanisms.Methods:（1）The YWHAG expression level and clinical correlation analysis were analyzed based on the transcriptomic database in gastric cancer and paracancerous tissues.Furthermore,gene aggregation enrichment analysis was applied to explore the signaling pathways of YWHAG in gastric cancer.（2）The tissues of gastric cancer and matching paracancerous tissues were collected from patients undergoing radical gastrectomy.The expression and localization of YWHAG in gastric cancer tissues and adjacent tissues were detected by immunohistochemical staining.The correlation between YWHAG expression and clinicopathological characteristics of gastric cancer patients was further analyzed.The m RNA and protein levels of YWHAG in gastric mucosal epithelial cells GES-1 and five gastric cancer cell lines were detected by q RT-PCR and western blotting,respectively.（3）Lentiviral transfection technology was used to construct the stable cell lines with YWHAG knockdown and overexpression,respectively.The effect of YWHAG on cell proliferation was detected by CCK8 assay and Ed U assay.The gastric cancer cell cycle and apoptosis were assessed by flow cytometry.The effect of YWHAG on the ability of cells migration and invasion was detected by wound-healing assay and trans-well assay.（4）The subcutaneous xenograft tumor model in nude mice was applied to evaluate the in vivo effect of YWHAG.Tumor proliferation indexes were detected by immunohistochemistry.（5）The regulatory effect of YWHAG on cell cycle,epithelial–mesenchymal transition（EMT）and PI3K/Akt signaling pathway was further verified by western blotting.Results:（1）Based on bioinformatics analysis,YWHAG was elevated in gastric cancer,and the high expression of YWHAG was positively correlated with the age of patients;（2）It was further confirmed that YWHAG was highly expressed in gastric cancer tissues and cells.The degree of differentiation was closely related to YWHAG expression;（3）YWHAG knockdown significantly inhibited the proliferation of MKN45 cells,induced cell cycle arrest and apoptosis,and also significantly inhibited the invasion and migration ability of MKN45 cells;YWHAG overexpression enhanced the proliferation ability of NCI-N87 cells,accelerated cell cycle progression,inhibited cell apoptosis,and enhanced cell invasion and migration ability;（4）Nude mouse subcutaneous tumorigenic model revealed that the tumor size in the YWHAG knockdown group was significantly reduced,and YWHAG overexpression promoted the growth of the tumor.Immunohistochemical results showed that Ki67 expression was decreased in YWHAG knockdown group,which inhibited tumor proliferation in vivo.（5）Pathway enrichment analysis showed that YWHAG was mainly involved in the regulation of cell cycle progression and EMT.YWHAG promoted the malignant progression of gastric cancer via the regulation of PI3K/Akt signaling pathway.Conclusion: The expression of YWHAG was up-regulated in gastric cancer tissues and cells,which was significantly related to the degree of tumor differentiation;YWHAG can promote the proliferation,migration and invasion of gastric cancer cells,and can also accelerate cell cycle progression and inhibit cell apoptosis;YWHAG was mainly involved in the malignant process of gastric cancer by activating PI3K/Akt signaling pathway.Therefore,YWHAG may serve as a potential target for gastric cancer.