OSU-03012 promotes caspase-independent but PERK-, cathepsin B-, BID-, and AIF-dependent killing of transformed cells

Mol Pharmacol. 2006 Aug;70(2):589-603. doi: 10.1124/mol.106.025007. Epub 2006 Apr 18.

Abstract

We determined one mechanism by which the putative phosphoinositide-dependent kinase (PDK)-1 inhibitor 2-amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]-phenyl}acetamide (OSU-03012) killed primary human glioma and other transformed cells. OSU-03012 caused a dose-dependent induction of cell death that was not altered by p53 mutation, expression of ERBB1 vIII, or loss of phosphatase and tensin homolog deleted on chromosome 10 function. OSU-03012 promoted cell killing to a greater extent in glioma cells than in nontransformed astrocytes. OSU-03012 and ionizing radiation caused an additive, caspase-independent elevation in cell killing in 96-h viability assays and true radiosensitization in colony formation assays. In a cell type-specific manner, combined exposure to OSU-03012 with a mitogen-activated protein kinase kinase 1/2 inhibitor, phosphoinositide 3-kinase/AKT inhibitors, or parallel molecular interventions resulted in a greater than additive induction of cell killing that was independent of AKT activity and caspase function. OSU-03012 lethality as a single agent or when combined with signaling modulators was not modified in cells lacking expression of BIM or of BAX/BAK. OSU-03012 promoted the release of cathepsin B from the lysosomal compartment and release of AIF from mitochondria. Loss of BH3-interacting domain (BID) function, overexpression of BCL(XL), and inhibition of cathepsin B function suppressed cell killing and apoptosis-inducing factor (AIF) release from mitochondria. In protein kinase R-like endoplasmic reticulum kinase-/- cells, the lethality of OSU-03012 was attenuated which correlated with reduced cleavage of BID and with suppression of cathepsin B and AIF release into the cytosol. Our data demonstrate that OSU-03012 promotes glioma cell killing that is dependent on endoplasmic reticulum stress, lysosomal dysfunction, and BID-dependent release of AIF from mitochondria, and whose lethality is enhanced by irradiation or by inhibition of protective signaling pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 3-Phosphoinositide-Dependent Protein Kinases
  • Apoptosis Inducing Factor / physiology*
  • BH3 Interacting Domain Death Agonist Protein / physiology*
  • Caspases / physiology*
  • Cathepsin B / physiology*
  • Cell Line, Tumor
  • Enzyme Inhibitors / pharmacology*
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Glioma / drug therapy
  • Glioma / pathology
  • Humans
  • Phosphatidylinositol 3-Kinases / physiology
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Pyrazoles / pharmacology*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Sulfonamides / pharmacology*
  • eIF-2 Kinase / physiology*

Substances

  • AIFM1 protein, human
  • Apoptosis Inducing Factor
  • BH3 Interacting Domain Death Agonist Protein
  • BID protein, human
  • Enzyme Inhibitors
  • OSU 03012
  • Pyrazoles
  • Reactive Oxygen Species
  • Sulfonamides
  • Phosphatidylinositol 3-Kinases
  • 3-Phosphoinositide-Dependent Protein Kinases
  • PERK kinase
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • eIF-2 Kinase
  • Extracellular Signal-Regulated MAP Kinases
  • Caspases
  • Cathepsin B