Fig. 1: Down-regulated circUBE2J2 in HCC tissues and prognostic significance.

A The cluster heat map showed the differentially expressed circRNAs in HCC tissues compared with those in adjacent nontumor tissues. Red color indicates high expression level, and green color indicates low expression level. B Volcano plots illustrate that among significantly different expressed circRNAs in HCC tissues relative to normal tissues. The green, red, and black points represent downregulated, upregulated, and no statistically significant difference circular RNAs (circRNAs), respectively. x-axis: log2 ratio of circRNA expression levels between normal and tumor tissues. y-axis: the P value (−log10 transformed) of circRNAs. C Upper panel: illustration of the annotated genomic region of UBE2J2, the putative different RNA splicing forms, and scheme illustrating the production of circUBE2J2. Convergent (blue) and divergent (red) primers were designed to amplify the linear or back-splicing products. Lower panel: total RNA from HepG2 cells with or without RNase-R treatment were subjected to polymerase chain reaction (PCR). D qRT-PCR analysis of circUBE2J2 and mUBE2J2 RNA after treatment with Actinomycin D at the indicated time points in HCC cells. E qRT-PCR detection show the differential expression of circUBE2J2 in 75 paired HCC tissues. F CircUBE2J2 expression among 75 patients was analyzed for survival probability. G The expression of circUBE2J2 was analyzed by in situ hybridization on HCC tissue. The representative photomicrographs of circUBE2J2 level with high, equal, and low in HCC tumors, as compared with normal tissues, were shown. The altered level of circUBE2J2 between HCC and non-tumor tissues in 50 HCC patients were summarized (n = number of cases). Data are presented as mean ± SD. *p < 0.05, **p < 0.01; NS no significance.