Fig 2: (a) Bioinformatics analysis of matching sequence of miR‐193a within 3′‐UTR of CircCHIPK3. MuT CircCPK3 3′‐UTR is the mutation of the match sequence of 3′‐UTR of CircCPK3with miR‐193a. (b) The predicted binding sites between HMGB1 and miR‐193a. MuT HMGB1 3′‐UTR is the mutation of the match sequence of 3′‐UTR of HMGB1 with miR‐193a. (c) Luciferase reporter assay revealed that miR‐193a binds to the 3′‐UTR of WT CircCHIPK3, not MuT CircCHIPK3 () miR‐NC, () miR‐193a mimic. (d) Luciferase activity was measured in MDA‐MB‐231 cells cotransfected with mimic NC or miR‐193a mimic and HMGB1‐wt or HMGB11‐mut reporter at 48 hours after transfection () miR‐NC, () miR‐193a mimic. HMGB1 was directly targeted by miR‐193a. Relative luciferase activity was quantified and the data were presented as mean ± SD (* P<0.05, ** P<0.01). (e) Representative images of western blot analysis of CircHIPK3 and miR‐193a on HMGB1 expressions. (f) Quantitative analysis of HMGB1 expressions influenced by CircHIPK3 and miR‐193a mimics (* P<0.05).

Fig 3: (a) Comparison of CirCHIPK3 expressions; (b) miR‐193a expressions; and (c) HMGB1 expressions between BC tissue and adjacent normal tissue in BC patients. (d) Correlation of miR‐193a expressions with CirCHIPK3 expressions in BC tissue. (e) Correlation of HMGB1 expressions with CirCHIPK3 expressions in BC tissue. (f) Kaplan‐Meier overall survival curves based on CirCHIPK3 expression levels. (g) HMGB1 expressions detected by IHC between normal tissue and BC tissue. (h) Quantitative analysis of HMGB1 expressions between normal tissue and BC tissue.

Fig 4: si‐CircCHIPK3 attenuated the HMGB1/PI3K/AKT signaling axis in MDA‐MB‐231 cells. (a–f) Representative immunoblots (a); quantitative evaluation of HMGB1 (b); PI3K phosphorylation (c); total p‐PI3K (d); AKT phosphorylation (e); and total AKT (f) expression in MDA‐MB‐231 cells subsequent to transient transfection with si‐CircCHIPK3 or CircNC. Results are represented as mean ± SD. *P < 0.05,** P < 0.01 (compared to vector group).