Alterations in microRNA (miRNA) expression have been reported in different cancers. We assessed the expression of 754 oncology-related miRNAs in esophageal adenocarcinoma (EAC) and evaluated their correlations with clinical parameters. We found that miR-221 and 483-3p were consistently upregulated in EAC cases 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 in patients expressing high miR-221 or miR-483-3p levels in all EACs (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). Moreover, we found that overexpression of miR-221 was associated with worse survival in the low-risk EAC group. 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 modified by miRNAs, we evaluatedtheir expression in different EAC cell lines, we transfected the corresponding mimic RNA (miRVANA) for either miR-221 or miR-483-3p and performed RNA-seq analysis. We found converging dysregulated genes involved in cancer progression, apoptosis, ATP synthesis and angiogenesis in miRNA-overexpressing cell lines, including a long non-coding RNA associated with oncogenesis, i.e., MALAT1.
In conclusion, miR-221 and 483-3p overexpression in EAC correlated with low cancer-related survival, indicating that they might be considered new biomarkers for patient stratification.