Absence of miR-378d Promoted The Malignant Phenotype of ESCC Through The AKT-β-Catenin and Hippo-p53 Signaling Pathway

Abstract Background: Chemoresistance is an important cause of malignant progression of esophageal squamous cell carcinomas (ESCCs). miR-378d is sharply reduced in paclitaxel (PTX)-resistance esophageal cancer cells by gene-expression profile analysis (RNA-Seq), but the mechanism of miR-378d-mediated tumor progression is unclear. Patients and methods: Herein, we detected miR-378d expression in 596 ESCC patients by in situ hybridization. Results showed that low miR-378d expression was associated with poor prognosis of ESCC patients, and that miR-378d absence enhanced carcinogenesis by promoting chemoresistance, colony formation, EMT, invasion, and metastasis. Results: Furthermore, miR-378d can target downregulated AKT1 expression by binding to the AKT1 mRNA 3′UTR, inactivating the AKT-β-catenin signaling pathway, and reducing the epithelial–mesenchymal transition marker Vimentin and the cancer stem cell marker ALDH1A1. miR-378d silencing in ESCC cells also promoted polyploidy formation in vitro and in vivo, and miR-378d inhibition suppressed the Hippo-p53 signaling pathway. Consequnetly, YAP and TAZ protein accumulated in nuclei and p53 expression decreased, which may promote the formation of ploidy tumor cells. Conclusions: Therefore, low miR-378d expression is a poor prognostic factor of ESCC patients and promotes polyploidy and cancer progression by activating AKT-β-catenin and suppressing the Hippo-p53 signaling pathway.