Inhibiting geranylgeranylation blocks growth and promotes apoptosis in pulmonary vascular smooth muscle cells

William W. Stark, Michelle A. Blaskovich, Bruce A. Johnson, Yimin Qian, Anil Vasudevan, Bruce Pitt, Andrew D. Hamilton, Saïd M. Sebti, Paul Davies

Research output: Contribution to journalArticle

Abstract

The activity of small GTP-binding proteins is regulated by a critical step in posttranslational processing, namely, the addition of isoprenoid lipids farnesyl and geranylgeranyl, mediated by the enzymes farnesyltransferase (FTase) and geranylgeranyltransferase I (GGTase I), respectively. We have developed compounds that inhibit these enzymes specifically and in this study sought to determine their effects on smooth muscle cells (SMC) from the pulmonary microvasculature. We found that the GGTase I inhibitor GGTI-298 suppressed protein geranylgeranylation and blocked serum-dependent growth as measured by thymidine uptake and cell counts. In the absence of serum, however, GGTI-298 induced apoptosis in these cells as measured by both DNA staining and flow cytometry. The FTase inhibitor FTI-277 selectively inhibited protein farnesylation but had a minor effect on growth and no effect on apoptosis. To further investigate the role of geranylgeranylated proteins in apoptosis, we added the cholesterol synthesis inhibitor lovastatin, which inhibits the biosynthesis of farnesyl and geranylgeranyl pyrophosphates. This also induced apoptosis, but when geranylgeraniol was added to replenish cellular pools of geranylgeranyl pyrophosphate, apoptosis was reduced to baseline. In contrast, farnesol achieved only partial rescue of the cells. These results imply that geranylgeranylated proteins are required for growth and protect SMC against apoptosis. GGTase I inhibitors may be useful in preventing hyperplastic remodeling and may have the potential to induce the apoptotic regression of established vascular lesions.

Original languageEnglish (US)
Pages (from-to)L55-L63
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume275
Issue number1 19-1
DOIs
StatePublished - Jul 1998

Keywords

  • Lovastatin
  • Prenyltransferase inhibitors
  • Pulmonary vasculature

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

Fingerprint Dive into the research topics of 'Inhibiting geranylgeranylation blocks growth and promotes apoptosis in pulmonary vascular smooth muscle cells'. Together they form a unique fingerprint.

  • Cite this