title: OSU-03012 promotes caspase-independent but PERK-, cathepsin B-, BID-, and AIF-dependent killing of transformed cells.
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.
authors.affiliation: Department of Biochemistry, Massey Cancer Center Virginia Commonwealth University, Richmond, VA 23298-0058, USA.
authors.forename: Adly
authors.initials: A
authors.lastname: Yacoub
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Park
authors.forename: David
authors.initials: D
authors.lastname: Hanna
authors.forename: Young
authors.initials: Y
authors.lastname: Hong
authors.forename: Clint
authors.initials: C
authors.lastname: Mitchell
authors.forename: Aditi P
authors.initials: AP
authors.lastname: Pandya
authors.forename: Hisashi
authors.initials: H
authors.lastname: Harada
authors.forename: Garth
authors.initials: G
authors.lastname: Powis
authors.forename: Ching-Shih
authors.initials: CS
authors.lastname: Chen
authors.forename: Costas
authors.initials: C
authors.lastname: Koumenis
authors.forename: Steven
authors.initials: S
authors.lastname: Grant
authors.forename: Paul
authors.initials: P
authors.lastname: Dent
mesh_terms: D064413:3-Phosphoinositide-Dependent Protein Kinases; D051033:Apoptosis Inducing Factor / Q000502:physiology*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000502:physiology*; D020169:Caspases / Q000502:physiology*; D002401:Cathepsin B / Q000502:physiology*; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005910:Glioma / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology*; D019892:eIF-2 Kinase / Q000502:physiology*
chemical_list: D064413:3-Phosphoinositide-Dependent Protein Kinases; D051033:Apoptosis Inducing Factor; D051023:BH3 Interacting Domain Death Agonist Protein; D020169:Caspases; D002401:Cathepsin B; D004791:Enzyme Inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D011720:Pyrazoles; D017382:Reactive Oxygen Species; D013449:Sulfonamides; D019892:eIF-2 Kinase; C494829:AIFM1 protein, human; C494814:BID protein, human; C500894:OSU 03012