OSU-03012 promotes caspase-independent but PERK-, cathepsin B-, BID-, and AIF-dependent killing of transformed cells.
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.
Yacoub
Adly
A
Department of Biochemistry, Massey Cancer Center Virginia Commonwealth University, Richmond, VA 23298-0058, USA.
Park
Margaret A
MA
Hanna
David
D
Hong
Young
Y
Mitchell
Clint
C
Pandya
Aditi P
AP
Harada
Hisashi
H
Powis
Garth
G
Chen
Ching-Shih
CS
Koumenis
Costas
C
Grant
Steven
S
Dent
Paul
P
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*
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