Concomitant dysregulation of microRNAs miR‐151‐3p and miR‐126 correlates with improved survival in resected cholangiocarcinoma

AbstractBackgroundMicroRNAs (miRNAs) are small non‐coding genes which become dysregulated in cancer and may predict survival. The role of miRNAs in outcomes in cholangiocarcinoma (CC) has not been reported.MethodsRNA was extracted from 32 resected CCs along with adjacent uninvolved bile duct epithelium. A total of 43 miRNAs were quantified using NanoString™. Clinicopathologic characteristics and outcomes were captured and compared. Overall survival curves were created using the Kaplan–Meier method; factors, including miRNA expression, were compared by log‐rank, chi‐squared or Cox regression analyses.ResultsAbsolute expression of each miRNA was compared with overall survival after excluding perioperative deaths (n= 3). One upregulated (miR‐151‐3p; P= 0.003) and one downregulated (miR‐126; P= 0.023) miRNA in resected CC relative to adjacent normal bile duct epithelium correlated with survival on univariate analysis. Clinical factors and these miRNAs were compared. Dysregulated miR‐151‐3p and miR‐126, respectively, were the only factors that correlated with improved overall survival [41.5 months vs. 12.3 months (P= 0.002) and 21.9 months vs. 15.1 months (P= 0.02), respectively]. In eight patients, both miRNAs were dysregulated. In the remainder, only one or neither showed dysregulation. Concomitant dysregulation correlated with the best overall survival (58.7 months vs. 15.1 months; P < 0.000; n= 8); clinicopathologic factors in these groups were otherwise similar.conclusionsIn resected CC, the concomitant dysregulation of both miR‐151‐3p and miR‐126 was the factor related to the greatest improvement in overall survival. Further analysis of the targets of these miRNAs may yield potential therapeutic targets or prognostic biomarkers

A MicroRNA Signature of Hypoxia

Recent research has identified critical roles for microRNAs in a large number of cellular processes, including tumorigenic transformation. While significant progress has been made towards understanding the mechanisms of gene regulation by microRNAs, much less is known about factors affecting the expression of these noncoding transcripts. Here, we demonstrate for the first time a functional link between hypoxia, a well-documented tumor microenvironment factor, and microRNA expression. Microarray-based expression profiles revealed that a specific spectrum of microRNAs (including miR-23, -24, -26, -27, -103, -107, -181, -210, and -213) is induced in response to low oxygen, at least some via a hypoxia-inducible-factor-dependent mechanism. Select members of this group (miR-26, -107, and -210) decrease proapoptotic signaling in a hypoxic environment, suggesting an impact of these transcripts on tumor formation. Interestingly, the vast majority of hypoxia-induced microRNAs are also overexpressed in a variety of human tumors

MiR-15a and miR-16-1 cluster functions in human leukemia

MicroRNAs (miRNAs) are short noncoding RNAs regulating gene expression that play roles in human diseases, including cancer. Each miRNA is predicted to regulate hundreds of transcripts, but only few have experimental validation. In chronic lymphocytic leukemia (CLL), the most common adult human leukemia, miR-15a and miR-16-1 are lost or down-regulated in the majority of cases. After our previous work indicating a tumor suppressor function of miR-15a/16-1 by targeting the BCL2 oncogene, here, we produced a high-throughput profiling of genes modulated by miR-15a/16-1 in a leukemic cell line model (MEG-01) and in primary CLL samples. By combining experimental and bioinformatics data, we identified a miR-15a/16-1-gene signature in leukemic cells. Among the components of the miR-15a/16-1 signature, we observed a statistically significant enrichment in AU-rich elements (AREs). By examining the Gene Ontology (GO) database, a significant enrichment in cancer genes (such as MCL1, BCL2, ETS1, or JUN) that directly or indirectly affect apoptosis and cell cycle was found