Figure 3. Downregulation of hsa_circ_0007580 significantly inhibited NSCLC cell proliferation. NSCLC cells were transfected with hsa_circ_0007580 shRNA1 or shRNA2 for 24 h. (A) The expression of hsa_circ_0007580 in A549 cells was detected using qRT-PCR. (B) The expression of hsa_circ_0007580 in NCI-H520 cells was detected using qRT-PCR. The optical density value of (C) A549 or (D) NCI-H520 cells was assessed following the CCK-8 assay. The proliferation of (E) A549 or (F) NCI-H520 cells was tested by Ki-67 staining. Red fluorescence indicates Ki-67. Blue fluorescence indicates DAPI; 200× magnification. **P<0.01 vs. control.