RACK1 Regulates Biological Activity Of Esophageal Squamous Cell Carcinoma Through ERK1/2 Signaling Pathway

BackgroundEsophageal cancer is one of the most frequently-occurring malignancies in China,and its incidence rate ranks sixth among the cancer constituents in China,and it ranks fourth among the patients in terms of death.In China,the incidence and mortality of esophageal cancer are relatively high,which seriously affects the physical and mental health of our people and places a certain burden on society.At present,among the pathological types of esophageal cancer in China,there are more squamous cell carcinomas,90%,while adenocarcinomas are less,accounting for less than 10%,and small cell carcinomas,undifferentiated cancers and other pathological types are relatively small.Receptor for activated C kinase 1(RACK1),a scaffold protein of many kinases and receptors,plays a key role in shuttle protein anchoring in intercellular space and participates in transcription/translation at specific locations events and stabilize protein activity.RACK1 acts as a mediator in multiple signal pathways,which interconnect different signal pathways to control the necessary cellular processes,namely cell growth,proliferation,migration,adhesion,differentiation,signal transduction and immunity reaction.Extracellular signal-regulated kinase(ERK)is part of a mitogen-activated protein kinase(MAPK),a conserved family of proteins that controls mitosis,survival,apoptosis,differentiation,and metabolism.The ERK1/2 signaling pathway increases the proliferation of differentiated cells,germline stem cells,and cancer stem cells,and becomes a key regulator of proliferation,migration,and apoptosis.ObjectiveThis study mainly explored whether RACK1 can regulate the proliferation,apoptosis,migration,and invasion of esophageal cancer cells through the ERK1/2 signaling pathway,and designed a series of experiments to initially explore the role of RACK1 and ERK1/2 signaling pathways in esophageal cancer cells.Provide some new ideas for its early diagnosis and prevention.Methods1.The mRNA and protein expression levels of RACK1 in esophageal cancer tissues and adjacent tissues were detected by qRT-PCR and western blot.The protein expression levels of RACK1 in paraffin tissues of esophageal cancer were detected by immunohistochemistry,and the clinical significance and correlation of RACK1 expression was analyzed by SAS 9.0 software.2.Use western blot and qRT-PCR detection technology to screen out the three vectors that interfere with RACK1 to the greatest extent to inhibit RACK1 expression,and prepare for subsequent experiments.The experiment was designed in three groups,including control group,negative control group and siRNA RACK1 group.Analyze the proliferation,apoptosis,migration and invasion of various esophageal cancer cells,and use western blot to analyze the levels of proliferation,apoptosis,migration and invasion related proteins.3.Use qRT-PCR and western blot to confirm the activation status of ERK1/2 signaling pathway;use siRNA to knock down the expression level of RACK1 protein,and analyze its effect on ERK1/2 signaling pathway related proteins.Results1.RACK1 protein was and mRNA highly expressed in esophageal cancer tissues.Increased expression of RACK1 protein was closely related to pathological grade,lymph node metastasis,and clinical stage of esophageal cancer(P<0.05);it had no correlation with patient gender,age,and tumor size(P>0.05).2.Knockdown of RACKl expression could inhibit the proliferation of esophageal cancer Ecas109 cells,reduce the expression of proliferation-related proteins ki67 and PCNA protein.promote the apoptosis of esophageal cancer Eca109 cells,increase the expression levels of apoptosis-related proteins cleaved caspase-3 and Bcl-2 was,and reduce the expression levels of Bax protein.3.Knocking down the expression level of RACK1 could inhibit the migration and invasion of esophageal cancer Eca109 cells,and reduce the expression of invasion-related proteins MMP-9 and MMP-3 in esophageal cancer cells.4.RACKl stimulated the proliferation of esophageal cancer Eca109 cells by regulating the ERK1/2 signaling pathway.Compared with the control group,siRNA RACK1 could reduce RACK1,MEK,ERK2,and P90RSK mRNA levels(P<0.05),and down-regulate RACK1,p-Mek,p-ERK2,and p-P90RSK protein levels(P<0.05).Compared with the siRNA Cullin7 2 group,siRNA RACK1 combined with ERK1/2 signaling pathway inhibitor PD98059 significantly increased the cell inhibition rate(P<0.05),and reduced the levels of RACK1,p-Mek,p-ERK2,and p-P90RSK protein significantly.(P<0.05).Conclusion1.High expression of RACK1 is closely related to the occurrence and development of esophageal cancer.2.Decreasing the expression of RACK1 can inhibit the proliferation,migration and invasion of esophageal cancer Eca109 cells,but promote its apoptosis.3.RACK1 regulates the biological function of esophageal squamous carcinoma cells Eca109 by activating ERK 1/2 signaling pathway,and participates in the occurrence and progression of esophageal squamous cell carcinoma to a certain extent.