Fig. 2

RRM2 silencing inhibited cell proliferation and induced S phase arrest. a Colony forming assay indicated the decreased numbers of colonies after transfecting siRRM2 in A549 and PC9 cells. b Statistical graphs of colony formation assay. c CCK8 assay showed that RRM2 silencing significantly inhibited A549 and PC9 cell proliferation. d Representative images of Ki-67 immunofluorescent staining of RRM2-deficient cells. Scale bar: 100 μm. e Quantification of Ki-67 positive cells. f, g A549 and PC9 cells were analyzed by flow cytometry for cell cycle 48 h after transfection. h Immunoblotting of the cell cycle related proteins, GAPDH was used as an internal control. All tests were repeated 3 times. *p < 0.05, **p < 0.01, ***p < 0.001