Fig. 1

Identification of circPPAP2B in highly invasive ccRCC cell lines. A Establishment of highly invasive and poorly invasive ccRCC cell lines. The highly invasive and poorly invasive ccRCC cell lines were generated through experimental protocols described in the Methods section. B Assessment of the invasive capabilities of invasive and poorly invasive ccRCC cell lines using transwell assay. Representative images of invasive cells and quantification of invasive cell numbers are shown. C High-throughput RNA sequencing to analyze the expression profiles of circRNAs in highly and poorly invasive ccRCC cell lines. D A Venn diagram illustrates the overlapping upregulated circRNAs between highly and poorly invasive ccRCC cell lines. E qPCR validated the upregulation of circPPAP2B in ccRCC tissues. F A schematic illustration of circPPAP2B originates from exons 3 to 5 of the PPAP2B gene. G Sanger sequencing validated the circPPAP2B junction site in circBase. H RNase R assay evaluates the stability of circPPAP2B in the ccRCC cell line. I Actinomycin D assay evaluates the stability of circPPAP2B in the ccRCC cell line. J RNA FISH was performed to determine the subcellular localization of circPPAP2B in ccRCC cell lines. K RNA FISH was performed to detect circPPAP2B expression in ccRCC tissues and normal tissues. L-M qPCR was performed to detect circPPAP2B expression on a cohort of 78 pairs of ccRCC tissues and adjacent non-tumorous tissues. N Kaplan–Meier survival analysis was conducted to evaluate the prognostic value of circPPAP2B in ccRCC. Data are represented as mean ± SEM. ***P < 0.001 vs. WT group