Suppression of c-myc, eIF4E, andCDK4 by RNAi reduces A549 and H23 proliferation. (A) Suppression of cell proliferation by c-myc, eIF4E and CDK siRNA in A549. (B) Suppression of cell proliferation in H23, as in part (A). A549 and H23 cells were transfected with c-myc, eIF4E and CDK siRNA, and assayed by MTT. (C) A549 and H23 cells were transiently transfected with vector control, miR-145 expression vector or miR-145 expression vector plus pCMV-CDK4, followed by MTT assay. Data are mean ± SD of three independent experiments. *P < 0.05 by Student's paired t-test compared to untreated cells (control).