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. 2020 Mar 5;11:193. doi: 10.3389/fgene.2020.00193

FIGURE 4.

FIGURE 4

circGNB1 promotes TNBC cell growth and proliferation via circGNB1-miR-141-5p-IGF1R axis. (A) TargetScan algorithm was used to predict binding sites of miR-141-5p within the 3′-UTR of IGF1R mRNA (http://www.targetscan.org). (B) Kaplan-Meier analysis of the association between miR-141-5p and overall survival in patients with breast cancer from public online database (http://kmplot.com/analysis). Two probes were used in this analysis (225330_at and 243358_at). (C) The relative expression level of IGF1R in breast cancer cell lines. Gray bar and black bar represent for TNBC and non-TNBC cell lines, respectively. (D,E) Luciferase reporter assay of MDA-MB-231 and BT549 cells co-transfected with miR-141-5p mimics and the 3′-UTR of IGF1R wild type or mutant luciferase reporter. (F,G) Enrichment of circGNB1, IGF1R and miR-141-5p on Ago2 assessed by RIP assay. (H,I) The enrichment of circGNB1 was decreased, while IGF1R expression was increased after knockdown of circGNB1 assessed by RIP assay. (J) Expression of IGF1R was decreased after transfection with si-circGNB1 detected by qPCR. (K) Expression of IGF1R was assessed by western bolt analysis after transfected with miR-141-5p mimics or inhibitors. (L) The impact of knockdown of circGNB1 on IGF1R protein expression in MDA-MB-231 and BT549 cells. *P < 0.05; **P < 0.01.