Endocrine Abstracts

Introduction and objectives: Circular RNAs (circRNAs) represent a class of endogenous noncoding RNAs that have recently been recognized as important regulators of gene expression and pathological networks. However, investigations on adrenocortical carcinoma (ACC) initiation and progression mechanisms only focus on key encoding genes, but neglect shedding an insight into circRNAs.

Materials and methods: We investigated the expression profile of circRNAs in three primary ACC and three Adrenocortical adenoma (ACA) tumor samples using a high-throughput circRNA microarray. Bioinformatic analyses were applied to study these differentially expressed circRNAs. Furthermore, qRT-PCR was performed to confirm these results. The expression levels and functions of circ0066659 were evaluated in ACC clinical specimens and cell lines.

Results: Here we identified 1447 differentially expressed circRNAs in primary ACCs as compared with ACAs, of which 849 were significantly upregulated and 598 were downregulated. Differential circRNAs expression between the two groups were validated by qRT-PCR assay. High expression of cricRNA0066659, one of the upregulated circRNAs in ACC, is closely correlated with a low cumulative survival rate and metastatic progression in ACC patients. Furthermore, our experimental analyses identified that cricRNA0066659 specifically binds to miR-506-3p and has a negative correlation with miR-506-3p, indicating that miR-506-3p as a direct target of cricRNA0066659.

Conclusion: Overall, the differential expression of multiple circRNAs and their clinical significance in ACC tissues as revealed by our study suggests that cricRNA0066659 is a novel metastatic factor and prognostic marker in ACC, we propose that cricRNA0066659 could be used as a potential target in ACC therapy.