Figure 2. Knockdown of circKIF4A attenuates the proliferation of papillary thyroid cancer cells. (A) Knockdown effect of circKIF4A was assessed in TPC-1 and KAT-5 cell line. (B) CCK-8 assays evaluated cell proliferation after knockdown of circKIF4A. (C) Colony formation assays revealed that circKIF4A silencing suppressed cell colony formatting ability. (D) Mouse xenograft models were established. Tumor volume was estimated in every four days. (E) GSH/GSSG ratio was detected.