Objective To explore the effect of miR-1-3p on the malignant biological behavior of human esophageal squamous cell carcinoma cells and the potential mechanisms. Methods The Gene Expression Omnibus (GEO) database was analyzed to screen differentially expressed miRNAs in esophageal squamous cell carcinoma (ESCC). qRT-PCR was used to detect the expression of miR-1-3p in human ESCC cell lines (KYSE30, KYSE150, KYSE410, KYSE510, and Eca109) and normal esophageal epithelial cell line HET-1A. CCK-8, wound healing, Transwell assays, and flow cytometry were applied to detect the effect of miR-1-3p on the proliferation, migration, invasion, and apoptosis of ESCC cells. Bioinformatics tool was used to predict the target genes of miR-1-3p. A Kaplan–Meier survival curve was drawn to analyze the correlation between STC2 expression and overall survival of patients in the ESCC cohort of the TCGA database. Fluorescence in situ hybridization was performed to verify the subcellular location of miR-1-3p in ESCC cells, and dual-luciferase reporter gene assay was performed to validate the regulation of miR-1-3p on stanniocalcin 2 (STC2). RNA immunoprecipitation assays were used to detect the binding of miR-1-3p and STC2. Western blot assay was performed to determine the effect of miR-1-3p on the expression of STC2 and endoplasmic reticulum stress pathway-related proteins, including p-PERK, p-eIF2α, and ATF4. CCK-8, wound healing, Transwell assays, and flow cytometry were applied to detect the effect of STC2 overexpression and knockdown on the proliferation, migration, invasion, and apoptosis of ESCC cells.
Results The expression of miR-1-3p was lower in ESCC cell lines than in HET-1A cells (all P<0.05). The transfection of miR-1-3p mimic decreased the proliferation, invasion, and migration of ESCC cells (all P<0.05) and promoted the apoptosis of ESCC cells (all P<0.001). Bioinformatics tool showed that STC2 was a target gene of miR-1-3p. The expression of STC2 in ESCC tissues was higher than that in normal esophageal epithelial tissues in the ESCC cohort of TCGA database and was negatively correlated with prognosis (all P<0.05). miR-1-3p was located in the cytoplasm and can directly bind to STC2 mRNA. The transfection of miR-1-3p mimic downregulated the expression of STC2, p-PERK, p-eIF2α, and ATF4 (all P<0.05). The overexpression of STC2 promoted the proliferation, invasion, and migration (all P<0.05) and inhibited the apoptosis of ESCC cells (all P<0.05). Knockdown of STC2 inhibited the proliferation, invasion, and migration (all P<0.05) and promoted the apoptosis of ESCC cells (all P<0.05).
Conclusion miR-1-3p inhibits the malignant biological behavior and promotes the apoptosis of esophageal squamous cell carcinoma cells by regulating STC2 possibly by suppressing the endoplasmic reticulum stress.
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