Background: Long noncoding RNAs (lncRNAs) are the chief products of human transcriptomes and have a major function in mediating gene expression. Abnormal lncRNA levels have been detected in gastric cancer. However, changes in lncRNA expression in advanced gastric adenocarcinoma (GA) are largely unexplored.
Methods: We studied the expression of lncRNAs and mRNAs in 6 advanced resected GA (ARGA) tissues using a lncRNA microarray chip.
Results: Among 22,870 lncRNAs expressed in ARGA and paired nonneoplastic tissues (non-GA), 1,769 and 1,710 were up- or downregulated, respectively, in all 6 ARGA tissues (≥ 2.0-fold, p < 0.05). The expression of 5 differentially expressed lncRNAs, HNF1A-AS1, RP11-62F24.2, GAS5, MALAT1, and H19 were randomly selected to be measured in 47 patients using real-time quantitative reverse transcription PCR (qRT-PCR), and the data were consistent with those obtained from the microarray chip. Analysis of their nearby coding genes (mRNAs) revealed that the main associated GO (gene ontology) classes were genes that regulate cellular metabolic processes, protein binding and receptor binding, whereas the main associated pathways were MAPK signaling, which regulates cell proliferation and differentiation and the apoptosis pathway, which is cancer-related. Some (n = 37) differentially expressed lncRNAs had direct annotated functions; among these lncRNAs, 27 were associated with cancer, cancer pathways, oncogenes, and tumor suppressor genes and with cell development and differentiation.
Conclusions: Expression differences in lncRNAs exist between advanced GA and noncancerous gastric tissues, so lncRNA expression patterns may explain gastric carcinogenesis and progression as well as serve as candidate biomarkers for the treatment of GA.