KLF5 inhibition decreases proliferation. A&B) PASMC cell proliferation was evaluated by PCNA and Ki67 immunostaining (nuclear translocation). PAH PASMC are significantly more proliferative than control PASMC and KLF5 inhibition (siRNA) decreases PAH-PASMC proliferation compared to siScr. C) Cyclin B1 (a proliferation biomarker) is increased in PAH-PASMC and KLF5 inhibition decreases significantly cyclin B1 expression. D) KLF5 inhibition in PAH-PASMC has been evaluated by qRT-PCR and Western blot. KLF5 inhibition, in PAH-PASMC using siRNA, decreases significantly KLF5 expression compared to the appropriate control: PAH-PASMC with siRNA Scramble (siScr). qRT-PCR were normalized to 18S gene and Western blot were normalized to SM-Actin (*, P < 0.05; **, P < 0.01; ***, P < 0.001).