Expression profiles and initial confirmation of long noncoding RNAs in Chinese patients with pulmonary adenocarcinoma

BACKGROUND The purpose of this study was to investigate differentially expressed long noncoding RNAs (lncRNAs) in pulmonary adenocarcinoma tissue and adjacent noncancerous tissue from Chinese patients using lncRNA expression microarray and preliminary analysis. METHODS RNA extracted from three paired pulmonary adenocarcinoma tissue and adjacent noncancerous tissue specimens was used to synthesize double-stranded complementary DNA after labeling and hybridization. The complementary DNA was labeled and hybridized to the lncRNA expression microarray, and array data were analyzed for hierarchical clustering. Gene coexpression networks were constructed to identify interactions among genes. To validate the microarray findings, we measured the relative expression levels of four random differentially expressed lncRNAs in the same tissue used for microarray using real-time quantitative polymerase chain reaction. The expression level of one lncRNA, AK124939, in the paired pulmonary adenocarcinoma/adjacent noncancerous tissue of another 30 patients was measured using real-time quantitative polymerase chain reaction. The experimental data were further analyzed and compared with clinical features. RESULTS Of 39,000 lncRNAs investigated, 704 were differentially expressed in pulmonary adenocarcinoma tissue; 385 were upregulated and 319 were downregulated compared with those in the adjacent noncancerous tissue (fold change ≥2 and ≤-2, P<0.05). AK124939 expression levels in poorly differentiated adenocarcinoma tissue were lower than those found in well to moderately differentiated adenocarcinoma tissue (P=0.05). CONCLUSION There are significant differences in the lncRNA expression profiles in Chinese patients with pulmonary adenocarcinoma. LncRNAs such as AK124939 may be anticancer factors related to the progression of pulmonary adenocarcinoma.