GSE137825
Circular RNAs expression profiles in canine mammary tumours
We explored the expression profile of circRNAs in canine mammary tumours using high-throughput sequencing technology. In our study, we analysed the expression profiles of 3 pairs of canine mammary tumours and their adjacent normal tissues. The total RNA was extracted, and a RNA library was constructed. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses revealed that these genes were mainly concentrated in 14 biological pathways. We selected 11 validated circRNAs and further confirmed the existence of these circRNAs by qRT-PCR. The circRNA-miRNA network diagram was constructed by using Cytoscape software. We found a total of 14851 circRNAs and 106 differentially expressed circRNAs in canine mammary tumours and their adjacent normal tissues (fold change = 2, P = 0.05). There were 64 upregulated circRNAs and 42 downregulated circRNAs. The main GO functions were the regulation of the regulated secretory pathway, the regulation of neurotransmitter secretion and the positive regulation of phagocytosis. Most of these pathways were related to the cGMP-PKG (cyclic guanosine monophosphate) signalling pathway, the cAMP (cyclic adenosine monophosphate) signalling pathway and the OXYTOCIN signalling pathway. CircRNAs have the function of adsorbing miRNA, similar to a sponge, and we further constructed the interaction network of circRNAs and miRNAs. The screened source genes closely related to canine mammary tumours included RYR2, PDE4D, ROCK2, CREB3L2 and UBA3. The screened circRNAs related to canine mammary tumours included chr27:26618544-26687235-, chr26:8194880-8201833+, and chr17:7960861-7967766-.In conclusion, our study uncovered circRNA expression profiles in canine mammary tumours. Moreover, some circRNAs may be used as potential biomarkers for screening dogs with high-risk canine mammary tumours. Overall design: Examination of the circRNAs  of 3 pairs of canine mammary tumours and their adjacent normal tissues.