Profile and validation of dysregulated long non­coding RNAs and mRNAs in ovarian cancer.

The dysregulation of long non­coding RNAs (lncRNAs) is associated with cancer development. The present study profiled differentially expressed lncRNAs in ovarian cancer (OC) versus normal ovarian tissues (NT) and investigated their potential functions in gene expression. OC tissues from 30 patients and NT specimens from 20 non­tumor patients were collected, and 5 cases of tumor and NT were subjected to lncRNA and mRNA microarray analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) was used to verify microarray data in all 30 cases. There were 2,870 differentially expressed lncRNAs (795 upregulated and 2,075 downregulated) and 2,658 differentially expressed mRNAs (1,014 upregulated and 1,644 downregulated) in OC. A total of 4 upregulated and 4 downregulated lncRNAs were validated using RT­qPCR. The data demonstrated that, with the exception of ENST00000453838 and ENST00000505048, the lncRNAs were consistent with the microarray data. Another differentially expressed lncRNA (BC041954) was assessed using independent tissue samples, and results further supported the microarray data. Moreover, GO analysis showed that the upregulated genes were involved in the 'development of the cell anatomical structure' (GO: 0048856; P=5.46x10­6), 'embryo and system development' and 'multicellular organismal development' in biological processes. By contrast, the downregulated genes were involved in 'gene expression' (GO: 0010476; P=1.81x10­6), 'nitrogen compound metabolic process', 'kidney development' and the 'cellular nitrogen compound metabolic process'. These differentially expressed lncRNAs could be classified into four classes, namely, the enhancer lncRNA nearby coding gene, HOX cluster, long­intergenic non­coding RNAs (lincRNAs) nearby coding gene and Rinn lincRNAs. Coding­non­coding gene co­expression network analysis showed the interregulation of lncRNAs and mRNAs in OC development. In conclusion, dysregulated lncRNA and mRNA expression could promote OC development. Further study may validate a number as OC markers and provide novel insights into ovarian cancer biology.