Dual-action inhibitors of HIF prolyl hydroxylases that induce binding of a second iron ion

Abstract

Inhibition of the hypoxia-inducible factor (HIF) prolyl hydroxylases (PHD or EGLN enzymes) is of interest for the treatment of anemia and ischemia-related diseases. Most PHD inhibitors work by binding to the single ferrous ion and competing with 2-oxoglutarate (2OG) co-substrate for binding at the PHD active site. Non-specific iron chelators also inhibit the PHDs, both in vitro and in cells. We report the identification of dual action PHD inhibitors, which bind to the active site iron and also induce the binding of a second iron ion at the active site. Following analysis of small-molecule iron complexes and application of non-denaturing protein mass spectrometry to assess PHD2·iron·inhibitor stoichiometry, selected diacylhydrazines were identified as PHD2 inhibitors that induce the binding of a second iron ion. Some compounds were shown to inhibit the HIF hydroxylases in human hepatoma and renal carcinoma cell lines.

Molecular and cellular mechanisms of HIF prolyl hydroxylase inhibitors in clinical trials

“…We performed titrations with Fe( ii ) to investigate whether PHD inhibition involves iron chelation in solution, as for some compounds upregulating HIF-α, e.g. dipyridine (DP) 9 , 75 and likely, desferrioxamine (DFO). 75 , 76 Both HeLa and Hep3b cells were pre-treated with DMSO, DFO, IOX4, FG-4592, GSK1278863, or Molidustat (6 hours), followed by administration of ferrous ammonium citrate (FAC, for 20 hours).…”

“…dipyridine (DP) 9 , 75 and likely, desferrioxamine (DFO). 75 , 76 Both HeLa and Hep3b cells were pre-treated with DMSO, DFO, IOX4, FG-4592, GSK1278863, or Molidustat (6 hours), followed by administration of ferrous ammonium citrate (FAC, for 20 hours). With DFO, HIF-1α upregulation is completely abolished by addition of ferrous iron, whereas with the other inhibitors, including DMOG, HIF-1α remained stable on iron addition (Fig.…”

A novel iron (II) preferring dopamine agonist chelator D-607 significantly suppresses α-syn- and MPTP-induced toxicities in vivo

“…To further probe into possible mechanisms involved in neuroprotection elicited by D-607 , we carried out a well characterized cell based assay evaluating effects of drug on HIF-1α levels as a surrogate for inhibition of iron-dependent prolyl hydroxylase activity (Callapina et al, 2005; Yeoh et al, 2013). It has been demonstrated that elevation of HIF-1α level as a result of inhibition of PHD prevents neuronal death and provides neuroprotection (Lee et al, 2009; Siddiq et al, 2005).…”

Multiple-layered nonwoven nanosheets consisting of multiwalled carbon nanotubes

“…Nonwovens are highly engineered solutions made up of a variety of materials including fibers, powders, particles, adhesives, films and other materials that provide a multitude of functionalities, for instances, hygienic applications , interlinings , geotextiles , carpet backings , automotive parts , filters , and wipes , etc.…”