Sildenafil acts as potentiator and corrector of CFTR but might be not suitable for the treatment of CF lung disease

Cell Physiol Biochem. 2012;29(5-6):775-90. doi: 10.1159/000265129. Epub 2012 May 11.


The phosphodiesterase-5 inhibitor sildenafil is an established and approved drug to treat symptoms of a variety of human diseases. In the context of cystic fibrosis (CF), a genetic disease caused by a defective CFTR gene (e.g. ΔF508-CFTR), it was assumed that sildenafil could be a promising substance to correct impaired protein expression. This study focuses on the molecular mechanisms of sildenafil on CFTR recovery. We used ΔF508-CFTR/wt-CFTR expressing Xenopus laevis oocytes and human bronchial epithelial cell lines (CFBE41o(-)/16HBE14o(-)) to investigate the pathways of sildenafil action. Cells were treated with sildenafil and cAMP-mediated current (I(m)), conductance (G(m)), and capacitance (C(m)) were determined. Sildenafil increased I(m), G(m), and C(m) of wt-CFTR and functionally restored ΔF508-CFTR in oocytes. These effects were also seen in CFBE41o(-) and 16HBE14o(-) cells. Transepithelial measurements revealed that sildenafil mediated increase (wt-CFTR) and restoration (ΔF508-CFTR) of channel activity. cGMP pathway blocker inhibited the activity increase but not CFTR/ΔF508-CFTR exocytosis. From these data we conclude that sildenafil mediates potentiation of CFTR activity by a cGMP-dependent and initiates cGMP-independent functional insertion of CFTR/ΔF508-CFTR molecules into the apical membranes. Thus, sildenafil is a corrector and potentiator of CFTR/ΔF508-CFTR. Yet, the necessary high doses of the drug for CFTR recovery demonstrate that sildenafil might not be suited as a therapeutic drug for CF lung disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bronchi / cytology
  • Bronchi / drug effects
  • Bronchi / metabolism
  • Cell Line
  • Cystic Fibrosis / drug therapy*
  • Cystic Fibrosis / metabolism
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Phosphodiesterase Inhibitors / pharmacology*
  • Phosphodiesterase Inhibitors / therapeutic use
  • Piperazines / pharmacology*
  • Piperazines / therapeutic use
  • Purines / pharmacology
  • Purines / therapeutic use
  • Sildenafil Citrate
  • Sulfones / pharmacology*
  • Sulfones / therapeutic use
  • Xenopus laevis


  • Phosphodiesterase Inhibitors
  • Piperazines
  • Purines
  • Sulfones
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Sildenafil Citrate