Fig 2: circ-BIRC6 silencing suppresses the growth of bladder cancer xenografts via regulating the miR-495-3p/XBP1 signaling axis. (A and B) Photographs of tumors. (C) Tumor weights. (D) Growth curves of T24 tumor volume. mRNA and protein expression of XBP1 in tumor tissues of nude mice were examined using (E) reverse transcription-quantitative PCR and (F) western blotting, respectively. (G) Ki-67 expression was evaluated using immunohistochemical staining. Magnification, ×200. (H) Expression levels of epithelial-mesenchymal transition-related proteins, including E-cadherin, N-cadherin, vimentin and snail, were examined using western blotting. ***P<0.001 vs. sh-NC; ##P<0.01, ###P<0.001 vs. sh-circ-BIRC6#1 + NC inhibitor. NC, negative control; sh, short hairpin RNA; circ-BIRC6, circular RNA baculoviral IAP repeat-containing 6; miR, microRNA; XBP1, X-box binding protein 1; snail, snail family transcriptional repressor 1.

Fig 3: circ-BIRC6 regulates the expression of XBP1 via miR-495-3p. (A) Binding region between XBP1 and miR-495-3p is shown. (B) Relative luciferase activities were detected in T24 cells. ***P<0.001 vs. XBP1 WT+ mimic NC. Protein and mRNA expression levels of XBP1 were examined using (C) western blotting and (D) RT-qPCR, respectively. **P<0.01, ***P<0.001 SV-HUC-1. (E) Western blotting and (F) RT-qPCR were employed to measure the protein and mRNA expression levels, respectively, of XBP1 after co-transfection with sh-circ-BIRC6#1 and miR-495-3p inhibitor. ***P<0.001 vs. sh-NC; ##P<0.01 vs. sh-circ-BIRC6#1 + NC inhibitor. NC, negative control; sh, short hairpin RNA; circ-BIRC6, circular RNA baculoviral IAP repeat-containing 6; miR, microRNA; XBP1, X-box binding protein 1; WT, wild-type; MUT, mutant; Luc, luciferase; R, Renilla; RT-qPCR, reverse transcription-quantitative PCR.