Exosomal circ_400068 enhances the proliferation and suppresses the apoptosis of kidney cells, and the effects are reversed by sh-circ_400068. (A) Expression of circ_400068 was elevated in HK-2 cells treated with RCC-Exo. (B) Transfection efficiency of sh-circ_400068 in HK-2 cells was assessed using reverse transcription quantitative PCR compared with the sh-NC. (C) Proliferative activity in HK-2 cells were enhanced following the treatment with RCC-Exo, which was abrogated by sh-circ_400068. (D) The RNA levels of Ki-67 were increased in cells treated with RCC-exo and reduced by sh-circ_400068. (E) The protein levels of Ki-67 were enhanced in cells treated with RCC-exo, which was reversed by sh-circ_400068. (F) Flow cytometry results demonstrated that the (G) cell apoptotic rate was significantly reduced in RCC-Exo-treated HK-2 cells, and the effects were rescued by the treatment with sh-circ_400068. (H) Western blotting results indicated that the (I) expression of cleaved caspase-7 was decreased in HK-2 cells treated with RCC-Exo, which was abrogated by sh-circ_400068. *P<0.05 vs. NC. NC, negative control; sh-, short hairpin RNA; RCC-Exo, exosomes isolated from the culture media of RCC cells; circ, circular RNA; RCC, RCC, renal cell carcinoma; OD, optical density.