Fig. 6

CREBZF suppresses ADAR1 expression via repressing STAT3 dimerization, leading to the biogenesis of circPAPD4. (A) Correlation between CREBZF and ADAR1 expression in 50 BC tissues were measured by Pearson’s Correlation analysis. (B) Relative expression of CREBZF, ADAR1, and circPAPD4 in MCF-7 and SKBR3 cells treated with OE-CREBZF or EV were assessed by RT-qPCR. (C) STAT3 luciferase reporter vectors were co-transfected with EV or OE-CREBZF into BC cells, and transcriptional activity of STAT3 were measured with relative luciferase activity. (D) After transfected with Flag-tagged CREBZF or EV, cells were treated with or without 10 ng/mL IL-6 stimulation. Then, immunoblots were performed to evaluate the expression levels of Flag, p-STAT3, and STAT3. (E) His-tagged STAT3 was co-transfected with Myc-tagged STAT3 and Flag-tagged CREBZF in the stimulation of 10 ng/mL human IL-6 into MCF-7 cells. Anti-His immunoprecipitates were immunoblotted with His, Myc, and Flag antibodies. (F) SKBR3 cells were co-transfected with Myc-STAT3 and Flag-CREBZF, followed by treatment with 10 ng/mL IL-6 stimulation; Then, STAT3 dimerization assay was conducted. (G) Relative RNA expression of ADAR1 and circPAPD4 in BC cells were detected by RT-qPCR after co-transfected with EV, OE-CREBZF, OE-STAT3, OE-CREBZF + EV, or OE-CREBZF + OE-STAT3. (H) The proliferation and apoptosis of MCF-7 and SKBR3 cells as indicated treatments were measured by EdU and TUNEL assays. (I) The expression of cyclin-D1, cyclin-E1, BCL-2, and BAX were evaluated by western blotting in MCF-7 and SKBR3 cells as indicated treatments. Data are presented as means ± SD. **p < 0.01; ***p < 0.001.