Differentially expressed circRNAs in melanocytes and melanoma cells and their effect on cell proliferation and invasion

Circular RNAs (circRNAs) play critical roles in the occurrence of human diseases, including cancer. However, the detailed functions of circRNAs in melanoma have not been fully elucidated. In the present study, a circRNA microarray was performed to analyze the variability of circRNAs in the low-metastatic melanoma WM35 cell line and in the high-meta-static melanoma WM451 cell line in comparison to control human melanocytes. The results revealed that five circRNAs were upregulated and four circRNAs were downregulated in both the WM35 and WM451 cells. qRT-PCR revealed an upregulated expression of circ0000082 and circ0016418 and a downregulation of circ0023988, circ0008157 and circ0030388 in the cells which was consistent with the results of the microarray assay. Functional tests revealed that knockdown of circ0023988, circ0008157 or circ0030388 significantly promoted the proliferation and invasion of the WM35 cells. Following the silencing of circ0000082 or circ0016418 in WM451 cells, the proliferation and invasion of the WM451 cells were inhibited. Bioinformatic analysis predicted that the circ0000082-, circ0023988- and circ0008157-circRNA-miRNA-mRNA network may participate in the occurrence, development, invasion and metastasis of malignant tumors. The present study revealed several differentially expressed circRNAs, indicating that the newly identified circRNAs may provide new therapeutic targets for melanoma.