The effect of circ_VANGL1 knockdown on cell viability, apoptosis, and doxorubicin resistance. (a–f) T24 and J82 cells were transfected with si-NC, si-circ#1, or si-circ#2, respectively. (a) The expression level of circ_VANGL1 in transfected T24 and J82 cells. (b) Cell viability was measured by CCK-8 assay. (c) Flow cytometry analysis was performed to assess cell apoptosis rate. (d) Different concentrations of doxorubicin were incubated with the transfected cells, and then cell apoptosis rate was determined by flow cytometry analysis. (e) IC50 values of the growth of T24 and J82 cells treated with doxorubicin. (f) The protein levels of c-caspase-3 and ki-67 in T24 and J82 cells. *P < 0.05, #
P < 0.05.