Influence of sildenafil and tadalafil on the enzyme- and transporter-inducing effects of bosentan and ambrisentan in LS180 cells

Biochem Pharmacol. 2013 Jan 15;85(2):265-73. doi: 10.1016/j.bcp.2012.11.020. Epub 2012 Dec 5.

Abstract

The combinations of the endothelin-1 receptor antagonists bosentan or ambrisentan with the phosphodiesterase 5 inhibitors sildenafil or tadalafil are current standard therapies of advanced pulmonary arterial hypertension. However, these drugs have a number of drug interactions. Changes of bosentan pharmacokinetics by sildenafil are attributed to reduced hepatic uptake as a consequence of inhibition of organic anion transporting polypeptides. We therefore tested in vitro the hypothesis that sildenafil and tadalafil reduce the enzyme- and transporter-inducing effects of bosentan or ambrisentan by preventing cellular access. Although intracellular concentrations of bosentan and ambrisentan (measured by high pressure liquid chromatography coupled with tandem mass-spectrometry) after four days of incubation of LS180 cells were lower when sildenafil or tadalafil were present, quantification of mRNA expression in these cells by real-time reverse transcription polymerase chain reaction revealed that bosentan and ambrisentan-mediated induction was stable or even increased in combination with sildenafil or tadalafil. For the drug transporter P-glycoprotein this was confirmed at the protein and functional level with highly significant correlations between P-gp mRNA, protein, and function. Moreover, using a reporter gene assay in LS180 cells, our study demonstrates for the first time that tadalafil is a potent, ambrisentan a weak, and sildenafil no activator of pregnane X receptor. In conclusion, our study demonstrates that although sildenafil and tadalafil indeed reduce intracellular concentrations of bosentan and ambrisentan in LS180 cells, they do not mitigate the inducing effects of these endothelin-1 receptor antagonists.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / genetics
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism
  • Antihypertensive Agents / analysis
  • Antihypertensive Agents / metabolism
  • Antihypertensive Agents / pharmacology
  • Biological Transport
  • Bosentan
  • Carbolines / adverse effects
  • Carbolines / pharmacology*
  • Cell Line, Tumor
  • Cytochrome P-450 CYP3A / genetics
  • Cytochrome P-450 CYP3A / metabolism
  • Drug Interactions
  • Endothelin A Receptor Antagonists*
  • Gene Expression Regulation / drug effects
  • Genes, Reporter / drug effects
  • Humans
  • Intestinal Absorption / drug effects
  • Intestinal Mucosa / metabolism
  • Intestines / drug effects*
  • Intestines / enzymology
  • Peroxisome-Targeting Signal 1 Receptor
  • Phenylpropionates / analysis
  • Phenylpropionates / metabolism
  • Phenylpropionates / pharmacology*
  • Phosphodiesterase 5 Inhibitors / pharmacology*
  • Piperazines / adverse effects
  • Piperazines / pharmacology*
  • Pregnane X Receptor
  • Promoter Regions, Genetic / drug effects
  • Purines / adverse effects
  • Purines / pharmacology
  • Pyridazines / analysis
  • Pyridazines / metabolism
  • Pyridazines / pharmacology*
  • RNA, Messenger / metabolism
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Receptors, Steroid / genetics
  • Receptors, Steroid / metabolism
  • Recombinant Proteins / metabolism
  • Sildenafil Citrate
  • Sulfonamides / analysis
  • Sulfonamides / metabolism
  • Sulfonamides / pharmacology*
  • Sulfones / adverse effects
  • Sulfones / pharmacology*
  • Tadalafil

Substances

  • ABCB1 protein, human
  • ATP Binding Cassette Transporter, Subfamily B
  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Antihypertensive Agents
  • Carbolines
  • Endothelin A Receptor Antagonists
  • Peroxisome-Targeting Signal 1 Receptor
  • Phenylpropionates
  • Phosphodiesterase 5 Inhibitors
  • Piperazines
  • Pregnane X Receptor
  • Purines
  • Pyridazines
  • RNA, Messenger
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Steroid
  • Recombinant Proteins
  • Sulfonamides
  • Sulfones
  • Tadalafil
  • Sildenafil Citrate
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human
  • ambrisentan
  • Bosentan