Fig. 1
CircRNA-CREIT was downregulated in TNBC. A A volcano plot showing the upregulated and downregulated circRNAs in breast cancer tissues. B Circos plot indicating the differentially expressed circRNAs. The outermost circle shows the chromosomal distribution of the circRNAs. The second circle shows the expression levels of the indicated circRNAs. The third circle indicates the circBase ID of the circRNAs. The fourth circle shows the logFC of the indicated circRNAs between the two groups. The innermost circle shows the logp values. C qRT-PCR assay was performed to detect the expression of circRNA-CREIT in the 6 paired breast cancer tissues and their normal counterparts. D Expression of circRNA-CREIT in 75 breast cancer tissues and normal mammary tissues detected by qRT-PCR assay. E ISH of circRNA-CREIT in breast cancer tissues and paired normal mammary tissues. Scale bars = 200 μm. F Kaplan–Meier survival analysis of circRNA-CREIThigh and circRNA-CREITlow patients. G Expression of circRNA-CREIT in breast cancer cell lines with different hormone receptor statuses. H (upper) Diagram showing the locus of circRNA-CREIT in the genome. (lower) Schematic illustration showing that exons 6–7 of human SPIDR circularize to form circRNA-CREIT. The black arrow represents the back-splicing site of circRNA-CREIT confirmed by Sanger sequencing. I Convergent and divergent primers were used to validate the loop structure of circRNA-CREIT. J The expression of circRNA-CREIT, linear SPIDR and β-actin in TNBC cells with or without RNase R treatment. K qRT-PCR analysis of circRNA-CREIT expression in cDNA reverse transcribed with random hexamer or oligo (dT) primers. L Relative RNA levels of circRNA-CREIT and linear SPIDR after actinomycin D treatment detected by qRT-PCR. M Detection of circRNA-CREIT expression in cytoplasmic and nuclear fractions of RNAs extracted from TNBC cells. N RNA FISH assay for circRNA-CREIT with the nucleus distinguished by DAPI. Scale bars = 10 μm. ns no significance; *p < 0.05; **p < 0.01; ***p < 0.001 compared with the controls