miRNA–221 and miRNA–483–3p Dysregulation in Esophageal Adenocarcinoma

Abstract

Alterations in microRNA (miRNA) expression have been reported in different cancers. We assessed the expression of 754 oncology–related miRNAs in esophageal adenocarcinoma (EAC) samples and evaluated their correlations with clinical parameters. We found that miR–221 and 483–3p were consistently upregulated in EAC patients vs. controls (Wilcoxon signed–rank test: miR–221 p < 0.0001; miR–483–3p p < 0.0001). Kaplan–Meier analysis showed worse cancer–related survival among all EAC patients expressing high miR–221 or miR–483–3p levels (log–rank p = 0.0025 and p = 0.0235, respectively). Higher miR–221 or miR–483–3p levels also correlated with advanced tumor stages (Mann–Whitney p = 0.0195 and p = 0.0085, respectively), and overexpression of miR–221 was associated with worse survival in low–risk EAC patients. Moreover, a significantly worse outcome was associated with the combined overexpression of miR–221 and miR–483–3p (log–rank p = 0.0410). To identify target genes affected by miRNA overexpression, we transfected the corresponding mimic RNA (miRVANA) for either miR–221 or miR–483–3p in a well–characterized esophageal adenocarcinoma cell line (OE19) and performed RNA–seq analysis. In the miRNA–overexpressing cells, we discovered a convergent dysregulation of genes linked to apoptosis, ATP synthesis, angiogenesis, and cancer progression, including a long non–coding RNA associated with oncogenesis, i.e., MALAT1. In conclusion, dysregulated miRNA expression, especially overexpression of miR–221 and 483–3p, was found in EAC samples. These alterations were connected with a lower cancer–specific patient survival, suggesting that these miRNAs could be useful for patient stratification and prognosis.