Fig. 7
Biogenesis of circPDHK1 is activated by HIF-2A. A HIF-2A expression data in KIRC samples and normal adjacent tissues from TGCA. B, C RT-qPCR to detected relative HIF-2A expression in 106 paired ccRCC tissues and normal adjacent tissues. D Comparison of HIF-2A expression between patients with WHO/ISUP stage III–IV (n = 38) and those with WHO/ISUP stage I–II (n = 68), detected by RT-qPCR. E Comparison of HIF-2A expression between patients with tumor T stage T1a-T1b (n = 71) and those with tumor T stage T2a-T4 (n = 35), detected by RT-qPCR. F Association analyses of HIF-2A expression and distant tumor metastasis. G, H Relationships between HIF-2A expression and VHL mutation (n = 106) and Ki-67 expression (n = 93). I RT-qPCR validation of correlation between circPDHK1 and HIF-2A expression in ccRCC paired tissues (n = 106). J, K Regulatory relationships between circPDHK1 and HIF-2A using RT‒qPCR detection and dual-luciferase assays in Caki-1 and 786-O cells. L Schematic of the HIF-2A binding motif and the HREs in the PDHK1 promoter obtained from the Contra V3 database (http://bioit2.irc.ugent.be/contra/v3) as indicated. We also designed three primers for the different binding sites in PDHK1 promoter. M, N ChIP assay to assess HIF-2A binding site interactions in the PDHK1 promoter region. *P < 0.05; **P < 0.01; ***P < 0.001; ns, no significance