ABSTRACT
Objective@# To find any differentially expressed circRNAs in oral leukoplakia (OLK) and oral lichen planus (OLP), to investigate the possible role of circRNAs in the pathogenesis of these two diseases.@*Methods@# This study obtained hospital ethical approval. High-throughput sequencing was used to detect differentially expressed circRNAs in OLK, OLP, oral squamous cell carcinoma and normal oral mucosal tissues. CircRNAs were verified by qRT-PCR, enzyme tolerance assays and Sanger sequencing. GO functional analysis and KEGG pathway analysis were performed to predict the functions of circRNAs in OLP. TargetScan and miRanda were applied to predict targeted miRNAs and mRNAs of circRNAs, and ceRNA networks were mapped. @*Results@#A total of 49 circRNAs were differentially expressed in OLK and OLP together, including 30 upregulated and 19 downregulated circRNAs. The five circRNAs confirmed with RT-qPCR, including circHLA-C, circRNF13, circTTN, circSEPN2 and circALDH3A2, were all abnormally expressed in OLK and OLP, among which circHLA-C was a key circRNA with trans splice sites, which was validated by expanding the sample size. ROC curve analysis showed that the area under the circHLA-C curve for predicting OLK was 0.955, and the area under the circHLA-C curve for predicting OLP was 0.988. GO functional analysis showed enrichment of many biological processes related to the immune process. The KEGG pathway with the highest enrichment score was "Natural killer cell mediated cytotoxicity". HLA-C was significantly enriched in these processes/pathways. CeRNA network analysis showed that circHLA-C interacted with a variety of miRNAs, such as hsa-miR-26a-5p, hsa-miR-129-5p, and hsa-miR-29a-3p.@*Conclusion@#Many circRNAs were differentially expressed in both OLK and OLP, circHLA-C being the most elevated. CircHLA-C is valuable for the early diagnosis of OLK and OLP and may serve as a potential biomarker for the diagnosis and prognosis of OLK and OLP.
ABSTRACT
Objective@#To investigate the differences and clinical significance of circRNA expression profiles in oral leukoplakia (OLK) tissues and normal oral mucosal (NOM) tissues.@*Methods@# High-throughput sequencing was used to detect differentially expressed circRNAs in 6 pairs of OLK and NOM tissues, and qRT-PCR was used to verify the expression of 10 circRNAs screened in 6 pairs of OLK and NOM tissues. The ring formation of circRNA was verified by RNase R digestion and Sanger sequencing, and the target circHLA-C was further verified by qRT-PCR in 20 pairs of OLK and NOM tissues. CircHLA-C was visualized using the UCSC genome browser (genome.ucsc.edu). The function of differentially expressed circRNAs was analyzed by GO and KEGG enrichment analyses. TargetScan and miRanda predicted the downstream miRNAs and mRNAs of the target circRNAs, and a ceRNA network related to the identified circRNAs was constructed in Cytoscape.@* Results@#Sequencing analysis showed that 366 circRNAs were significantly differentially expressed in OLK tissues, including 65 upregulated and 301 downregulated circRNAs. After qRT-PCR verification, 7 of the 10 screened circRNAs were expressed consistent with the sequencing results. The upregulated circHLA-C was confirmed to be a real circRNA with back-splice junction sites by RNase R digestion and Sanger sequencing. Correlation analysis showed a positive correlation between circHLA-C and the degree of OLK dysplasia. ROC curve analysis suggested that circHLA-C had potential value in diagnosing OLK with high accuracy and specificity.@*Conclusion@#CircRNA was significantly abnormally expressed in OLK tissues, and the upregulation of circHLA-C may be related to the degree of OLK dysplasia, providing guiding value for the diagnosis of OLK in the future.