Fig. 1

CircCAPG is highly expressed in TNBC. (A) Differentially expressed circRNAs in TNBC were analyzed based on the GEO database. Five circRNAs were identified to simultaneously exist in both GSE113230 and GSE101123 and thus selected. (B) RT-PCR analysis of five circRNAs in TNBC cell lines. (C) Schematic illustration of circCAPG conformation. The exon 6, exon 7, and exon 8 of CAPG mRNA formed circCAPG through back splicing. RNA sequencing of the back-splicing site of circCAPG was shown below. (D) qPCR of circCAPG in TNBC and adjacent tissues of TNBC. n = 132. (E) qPCR of circCAPG in various TNBC cell lines. (F) PCR products of circCAPG in cDNA and gDNA amplified using convergent or divergent primers in MDA-MB-231 and MDA-MB-468. (G) The half-life of linear CAPG and circCAPG in MDA-MB-231 and MDA-MB-468. (H) The distribution of circCAPG in the nuclear and cytoplasmic fraction. U6 and GAPDH were used as nuclear and cytoplasmic markers, respectively. (I) qPCR of circCAPG in TNBC tissue at different stages. (J) Survival analysis of 132 TNBC patients. The cutoff of ‘low’ and ‘high’ expression levels of circCAPG was decided according to the median of the circCAPG expression in TNBC tissue. (K) ROC curve of the diagnostic value of circCAPG. All data were representative of at least three biological replicates and shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001