CircRASSF2 promotes IGF1R and osteosarcoma metastasis via sponging miR-6838-5p

BACKGROUND: Osteosarcoma (OS) often occurs in children and adolescents and is highly malignant. Analyzing the pathogenesis of OS has great significance for prognosis and the discovery of new treatment strategies. METHODS: The effects and mechanism of circular RNA (circRNA) on OS were analyzed, as was the correlation between circRASSF2 and insulin-like growth factor 1 receptor (IGF1R) in data from The Cancer Genome Atlas (TCGA). The expression levels of microRNA (miR)-6838-5p and circRASSF2 in OS cells and osteoblasts were detected. The dual luciferase report was used to verify the targeting relationship. OS cells overexpressing circRASSF2, miR-6838-5p and/or IGF1R were constructed. The expression level of IGF1R and the biological behavior of the cells were detected. Eighty-two pairs of OS tissue and adjacent normal tissue samples were collected, and the levels of circRASSF2, miR-6838-5p, and IGF1R mRNA were detected by reverse transcription-quantitative PCR (RT-qPCR). RESULTS: Compared with osteoblasts, OS cells showed lower expression of miR-6838-5p and higher expression of circRASSF2. The dual luciferase report confirmed that miR-6838-5p targeted IGF1R. Overexpression of IGF1R significantly blocked the anticancer effects of miR-6838-5p. The dual luciferase report verified that circRASSF2 targeted miR-6838-5p, and promoted the expression of IGF1R. Overexpression of circRASSF2 not only promoted the malignant biological behavior of OS cells, but also blocked the anticancer effects of miR-6838-5p. In OS tissue, circRASSF2 and IGF1R were upregulated, and the two were positively correlated. MiR-6838-5p was downregulated, which negatively correlated with both circRASSF2 and IGF1R. High levels of circRASSF2 were associated with higher stage and metastasis of OS. CONCLUSIONS: In conclusion, the promoting effects of IGF1R on OS are targeted by miR-6838-5p. CircRASSF2 restored the expression of IGF1R by sponging miR-6838-5p, thereby promoting the progression of OS.