| ObjectiveGastric cancer(GC)is a common malignant tumor in the digestive system.Various factors have been found to affect the development of gastric cancer,but the molecular mechanism is still not fully elucidated.Therefore,finding the key molecules affecting the progression of gastric cancer is clinically important for the targeted therapy of gastric cancer.RNA binding proteins(RBPs)can bind to single-or double-stranded RNA to form ribonucleoprotein complexes,that are involved in the regulating of many cancer-related biological processes.Bicaudal C homolog 1(BICC1)is an RNA binding protein that can regulate gene expression by regulating protein translation.However,its role and molecular mechanism in gastric cancer are not clear.Paired-related homeobox 1(PRRX1)is usually used as a transcription factor to regulate the expression of target genes.In gastric cancer,PRRX1 promotes epithelial-mesenchymal transition(EMT)and affects the invasion and migration of gastric cancer cells.However,the upstream signaling pathways activated by PRRX1 in gastric cancer are not fully understood.Therefore,this study aims to research the effect and molecular mechanism of RNA binding protein BICC1 on the malignant biological behavior of gastric cancer,and the function and mechanism of BICC1 in promoting malignant progression of gastric cancer through binding to PRRX1.Finally,explore the role of BICC1/PRRX1/MAPK pathway in the development of gastric cancer.Methods1.The expression of BICC1 in clinical patients was detected by Western blot and immunohistochemical staining,and analyzed its correlation with clinicopathological parameters.The survival curves were also plotted according to the immunohistochemical results to analyze the relationship between BICC1 expression and patient prognosis.2.The cell lines overexpressing and knocking down BICC1 were constructed.The effects of BICC1 expression on proliferation and migration ability of gastric cancer cells were detected by CCK-8 assay,EdU assay,scratch assay and Transwell assay.The effects of BICC1 on the expression of proliferation and EMT related molecules in gastric cancer cells were detected by Western blot.3.The model of subcutaneous tumor formation and caudal vein metastasis in nude mice were constructed to examine the effect of BICC1 on tumor growth and metastasis in vivo.4.BICC1 was confirmed to be associated with PRRX1 expression in gastric cancer tissues and gastric cancer cells by immunohistochemical staining,RNA immunoprecipitation,and Western blot techniques.5.PRRX1 stable knockdown cell lines were constructed,and the effects of cell proliferation,migration,and EMT in control,PRRX1 knockdown,and PRRX1 knockdown combined with BICC1 overexpression or knockdown groups were examined using Western blot,CCK-8 assay,EdU assay,scratch assay,Transwell assay,and in vivo animal models.6.The effect of BICC1 expression on MAPK-related molecules were examined by Western blot.The effect on the expression of proliferation and EMT related molecules after the application of p38 MAPK inhibitor were also examined by Western blot.Results1.BICC1 expression was upregulated in gastric cancer tissues and was significantly associated with poor prognosis in gastric cancer patients.The expression of BICC1 was also significantly associated with tumor size,depth of infiltration,lymph node metastasis and clinical stage of gastric cancer.2.In vitro experiments demonstrated that BICC1 expression could affect the proliferation and migration ability of gastric cancer cells.3.The results of subcutaneous tumor formation and caudal vein transfer in nude mice showed that BICC1 promoted the proliferation and metastasis of gastric cancer cells in vivo.4.In gastric cancer tissues,the expression of BICC1 was positively correlated with PRRX1,5.RNA immunoprecipitation assays and Western blot experiments confirmed that BICC1 binds to PRRX1 RNA and promotes PRRX1 expression.6.The results of experiments in vitro and in vivo showed that knockdown of PRRX1 inhibited the proliferation,migration and EMT related characteristics of gastric cancer cells.Downregulation of PRRX1 expression inhibited the promotion effects of overexpression BICC1 on proliferation,migration and EMT,and promoted the inhibitory effects of knocking down BICC1 on cell proliferation,migration and EMT.7.Western blot results showed that activation of the BICC1/PRRX1 pathway promoted the expression of MAPK-related molecules.Overexpression of BICC1 induced elevated expression of proliferation and EMT related proteins was suppressed when p38 MAPK inhibitor was used.Conclusions1.BICC1 is highly expressed in gastric cancer tissues and gastric cancer cells,and is closely related to the malignant process and clinical prognosis of gastric cancer.2.BICC1 binds to PRRX1 and promotes the development of gastric cancer through upregulation of PRRX1 expression.3.BICC1/PRRX1 promotes the expression of proliferation and EMT related molecules in gastric cancer cell through MAPK pathway. |
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