MTA1 Promotes Tumorigenesis And Development Of Esophageal Squamous Cell Carcinoma Via Activating MEK/ERK/p90RSK Signaling Pathway

Objective Metastasis-associated protein 1(MTA1),a cancer progression-related epigenetic regulator,is upregulated in multiple cancer cells and is closely related to malignant phenotypes including invasion and metastasis of tumor.The role of MTA1 in the development and progression of esophageal squamous cell carcinoma(ESCC)and its underlying mechanisms are not clear.In this study,we investigate the effects of MTA1 on the tumorigenesis and development of ESCC and explore its underlying mechanism.Methods Western blotting assay and immunohistochemistry of ESCC tissue microarray consisting of 90 samples were used to evaluate the expression of MTA1 in ESCC cell lines and tissues;Chemical carcinogen 4-nitroquinoline 1-oxide(4-NQO)was used to establish ESCC tumorigenesis model and investigate the role of MTA1 in ESCC tumorigenesis;Real-time proliferation assay(RTCA)and colony formation assay were used to evaluate the effects of MTA1 to colony formation and proliferation of normal human esophageal epithelial cell and ESCC cells;the invasion and migration of ESCC cells were detected by transwell assay;mice subcutaneous tumor xenograft assay was used to investigate the effect of knockdown MTA1 in ESCC cells to ESCC proliferation in vivo;RNA-sequencing(RNA-seq)analysis combined with western blot assay were used to investigate the potential pathway regulating by MTA1 in ESCC;ESCC cells were treated with MAPK pathway targeting inhibitors to detect the inhibitory effect on colony formation and invasion and migration of ESCC cells.Results We found that the expression of MTA 1 was significantly upregulated in esophageal squamous cell carcinoma cells and tissues compared with normal.We found that the average tumor numbers of MTA1 transgenic group induced by 4-NQO were significantly higher than that in wild type group,and Ki-67 positive cancer cells were also higher in MTA 1-transgenic group.Overexpressed MTA1 could increase colony formation and proliferation of human normal esophageal epithelial cells.In addition,overexpression of MTA I in KYSE410 and KYSE450 cells increased the colony formation by 318.1%±3.8%and 17.2%±2.8%,the cell migration by 43.7%±12.3%and 66.6%±22.4%,and the invasive capacity by 37.5%±25.6%and 164.3±44.7%,respectively,while knocking down MTA1 in ESCC cells significantly decreased colony formation,invasion and migration in vitro and inhibited growth of xenograft tumor in vivo.In mechanism,we found that MTA1 activating MAPK pathway in ESCC cells;phosphorylation of MEK,ERK and their downstream target p90RSK was significantly decreased after MTA1 knockdown in ESCC cells,while increased in MTA1-overexpressing cells.Moreover,colony formation,invasion and migration potential were dramatically suppressed when cells overexpressed MTA1 were treated with MEK or ERK inhibitors.Conclusions MTA1 was upregulated in ESCC cells and ESCC tissues;knockdown or overexpressed MTA1 in cancer cell significantly impared colony formation,invation,migration and the growth of xenograft tumor in vivo.MTA1 promoted ESCC tumorigenesis and development by activating MEK/ERK/p90RSK pathway,the target inhabitors of MAPK signaling pathway dramatically inhibited the malignant phenotype of ESCC cells.Objective To initially screen the genes associated with chemotherapy resistance in esophageal cancer cells and verify their correlations with poor prognosis in patients with esophageal cancer,and predict the possible regulatory mechanism of esophageal cancer resistance.Methods The drug sensitivity data of esophageal cancer cell lines from GDSC database were analyzed to screen cell lines that were relatively sensitive or resistant to both cisplatin and docetaxel.In order to obtain differentially expressed genes,the transcriptome data of two groups of cell lines were analyzed by the edgeR package in a rule that was the log2(fold change)>1 or<-1 and P value<0.05.The analysis of GO biological processes was performed in highly expressed genes of drug-resistant group to identify possible signaling pathways related with drug-resistant,and the target genes related to chemotherapy resistance were identified based on previous studies.The correlation between target genes with clinical pathological features and prognosis of patients was verified in the tissue transcriptome data of esophageal cancer patients.Finally,the interaction proteins of target gene encoded protein were predicted online by the STRING database,and its function mechanism was analyzed.Results We obtained 5 cell lines with resistance to both cisplatin and docetaxel,and 5 sensitive cell lines,respectively.According to transcriptome data of the two group cell lines,1097 differentially expressed genes were obtained,including 532 genes highly expressed in the drug resistant group and 565 low expressed genes.The results of GO enrichment analysis for the highly expressed genes indicated that the receptor protein tyrosine kinase pathway was the most significantly enriched.The expression level of FGR involved in this pathway was significantly correlated with tumor T stage(P=0.021),clinical stage(P=0.007)and the survival(P=0.0021)of patients with esophageal cancer.In addition,protein interaction analysis indicated that FGR interacted directly or indirectly with multiple proteins,mainly in the form of kinases.Conclusion The receptor protein tyrosine kinase pathway is the most significant signaling pathway associated with esophageal cancer cell resistance.The expression level of FGR in this signaling pathway is significantly correlated with the pathological stage and prognosis of patients with esophageal cancer.FGR may regulate the drug resistance of esophageal cancer cells by phosphorylating downstream target proteins.