A MicroRNA cluster at 14q32 drives aggressive lung adenocarcinoma.

PURPOSE: To determine whether different subtypes of lung adenocarcinoma (AC) have distinct microRNA (miRNA) expression profiles, and to identify miRNAs associated with aggressive subgroups of resected lung AC. EXPERIMENTAL
DESIGN: miRNA expression profile analysis was performed in 91 resected lung AC and 10 matched nonmalignant lung tissues using a PCR-based array. An independent cohort of 60 lung ACs was used for validating by quantitative PCR the top 3 prognostic miRNAs. Gene-expression data from 51 miRNA profiled tumors was used for determining transcript-specific miRNA correlations and gene-enrichment pathway analysis.
RESULTS: Unsupervised hierarchical clustering of 356 miRNAs identified 3 major clusters of lung AC correlated with stage (P = 0.023), tumor differentiation (P < 0.003), and IASLC histologic subtype of lung AC (P < 0.005). Patients classified in cluster 3 had worse survival as compared with the other clusters. Eleven of 22 miRNAs associated with poor survival were encoded in a large miRNA cluster at 14q32. The top 3 prognostic 14q32 miRNAs (miR-411, miR-370, and miR-376a) were validated in an independent cohort of 60 lung AC. A significant association with cell migration and cell adhesion was found by integrating gene-expression data with miR-411, miR-370, and miR-376a expression. miR-411 knockdown significantly reduced cell migration in lung AC cell lines and this miRNA was overexpressed in tumors from patients who relapsed systemically.
CONCLUSIONS: Different morphologic subtypes of lung AC have distinct miRNA expression profiles, and 3 miRNAs encoded at 14q32 (miR-411, miR-370, and miR-376a) were associated with poor survival after lung AC resection. ©2014 American Association for Cancer Research.